Printer (computing)From Wikipedia, the free encyclopedia

A modern printer with scanning/copying capability

In computing, a printer is a peripheral which produces a text and/or graphics of

documents stored in electronic form, usually on physical print media such as paper or

transparencies. Many printers are primarily used as local peripherals, and are attached

by a printer cable or, in most newer printers, a USB cable to a computer which serves as

a document source. Some printers, commonly known as network printers, have built-in

network interfaces, typically wireless and/orEthernet based, and can serve as a hard

copy device for any user on the network. Individual printers are often designed to

support both local and network connected users at the same time. In addition, a few

modern printers can directly interface to electronic media such as memory cards, or to

image capture devices such as digital cameras, scanners; some printers are combined

with a scanners and/or fax machines in a single unit, and can function as photocopiers.

Printers that include non-printing features are sometimes called multifunction

printers (MFP), multi-function devices (MFD), or all-in-one (AIO) printers. Most MFPs

include printing, scanning, and copying among their features.

Consumer and some commercial printers are designed for low-volume, short-turnaround

print jobs; requiring virtually no setup time to achieve a hard copy of a given document.

However, printers are generally slow devices (30 pages per minute is considered fast;

and many inexpensive consumer printers are far slower than that), and the cost per

page is actually relatively high. However, this is offset by the on-demand convenience

and project management costs being more controllable compared to an out-sourced

solution. The printing press remains the machine of choice for high-volume, professional

publishing. However, as printers have improved in quality and performance, many jobs

which used to be done by professional print shops are now done by users on local

printers; see desktop publishing. The world's first computer printer was a 19th century

mechanically driven apparatus invented by Charles Babbage for his Difference Engine.[1]

A virtual printer is a piece of computer software whose user interface and API resemble

that of a printer driver, but which is not connected with a physical computer printer.

Printing technology

Printers are routinely classified by the technology they employ; numerous such technologies have been developed

over the years. The choice of engine has a substantial effect on what jobs a printer is suitable for, as different

technologies are capable of different levels of image or text quality, print speed, low cost, noise; in addition, some

technologies are inappropriate for certain types of physical media, such as carbon paper or transparencies.

A second aspect of printer technology that is often forgotten is resistance to alteration: liquid ink, such as from an

inkjet head or fabric ribbon, becomes absorbed by the paper fibers, so documents printed with liquid ink are more

difficult to alter than documents printed with toner or solid inks, which do not penetrate below the paper surface.

Cheques should either be printed with liquid ink or on special cheque paper with toner anchorage.[2] For similar

reasons carbon film ribbons for IBM Selectric typewriters bore labels warning against using them to type negotiable

instruments such as cheques. The machine-readable lower portion of a cheque, however, must be printed

using MICR toner or ink. Banks and other clearing houses employ automation equipment that relies on

the magnetic flux from these specially printed characters to function properly.

[edit]Modern print technology

The following printing technologies are routinely found in modern printers:

[edit]Toner-based printersMain article: Laser printer

A laser printer rapidly produces high quality text and graphics. As with digital photocopiers and multifunction

printers (MFPs), laser printers employ a xerographic printing process but differ from analog photocopiers in that the

image is produced by the direct scanning of a laserbeam across the printer's photoreceptor.

Another toner-based printer is the LED printer which uses an array of LEDs instead of a laser to cause

toner adhesion to the print drum.

[edit]Liquid inkjet printers

Inkjet printers operate by propelling variably-sized droplets of liquid or molten material (ink) onto almost any sized

page. They are the most common type of computer printer used by consumers.

[edit]Solid ink printersMain article: Solid ink

Solid ink printers, also known as phase-change printers, are a type of thermal transfer printer. They use solid sticks

of CMYK-coloured ink, similar in consistency to candle wax, which are melted and fed into a piezo crystal operated

print-head. The printhead sprays the ink on a rotating, oil coated drum. The paper then passes over the print drum,

at which time the image is transferred, or transfixed, to the page. Solid ink printers are most commonly used as

colour office printers, and are excellent at printing on transparencies and other non-porous media. Solid ink

printers can produce excellent results. Acquisition and operating costs are similar to laser printers. Drawbacks of

the technology include high energy consumption and long warm-up times from a cold state. Also, some users

complain that the resulting prints are difficult to write on, as the wax tends to repel inks from pens, and are difficult

to feed through automatic document feeders, but these traits have been significantly reduced in later models. In

addition, this type of printer is only available from one manufacturer, Xerox, manufactured as part of their Xerox

Phaser office printer line, it is also available by various Xerox concessionaires [1].[3] Previously, solid ink printers

were manufactured by Tektronix, but Tek sold the printing business to Xerox in 2001.

[edit]Dye-sublimation printersMain article: Dye-sublimation printer

A dye-sublimation printer (or dye-sub printer) is a printer which employs a printing process that uses heat to

transfer dye to a medium such as a plastic card, paper or canvas. The process is usually to lay one colour at a

time using a ribbon that has colour panels. Dye-sub printers are intended primarily for high-quality colour

applications, including colour photography; and are less well-suited for text. While once the province of high-end

print shops, dye-sublimation printers are now increasingly used as dedicated consumer photo printers.

[edit]Inkless printers[edit]Thermal printersMain article: Thermal printer

Thermal printers work by selectively heating regions of special heat-sensitive paper. Monochrome thermal

printers are used in cash registers, ATMs, gasoline dispensers and some older inexpensive fax machines. Colours

can be achieved with special papers and different temperatures and heating rates for different colours; these

coloured sheets are not required in black-and-white output. One example is the ZINK technology.

[edit]UV printers

Xerox is working on an inkless printer which will use a special reusable paper coated with a few micrometres of UV

light sensitive chemicals. The printer will use a special UV light bar which will be able to write and erase the paper.

As of early 2007 this technology is still in development and the text on the printed pages can only last between 16–

24 hours before fading.[4]

[edit]Obsolete and special-purpose printing technologies

An Epson MX-80

The following technologies are either obsolete, or limited to special applications though most were, at one time, in

widespread use.

Impact printers rely on a forcible impact to transfer ink to the media, similar to the action of atypewriter. All but

the dot matrix printer rely on the use of formed characters, letterforms that represent each of the characters that

the printer was capable of printing. In addition, most of these printers were limited to monochrome printing in a

single typeface at one time, although bolding andunderlining of text could be done by "overstriking", that is, printing

two or more impressions in the same character position. Impact printers varieties include, typewriter-derived

printers, teletypewriter-derived printers, daisy wheel printers, dot matrix printers and line printers. Dot matrix

printers remain in common use in businesses where multi-part forms are printed, such as car rental services. An

overview of impact printing[5] contains a detailed description of many of the technologies used.

Pen-based plotters were an alternate printing technology once common in engineering and architectural firms.

Pen-based plotters rely on contact with the paper, but not impact, per se, and special purpose pens that are

mechanically run over the paper to create text and images.

[edit]Typewriter-derived printersMain articles: Friden Flexowriter and IBM Selectric typewriter

Several different computer printers were simply computer-controllable versions of existing electric typewriters.

The Friden Flexowriter and IBM Selectric typewriter were the most-common examples. The Flexowriter printed

with a conventional typebar mechanism while the Selectric used IBM's well-known "golf ball" printing mechanism.

In either case, the letter form then struck a ribbon which was pressed against the paper, printing one character at a

time. The maximum speed of the Selectric printer (the faster of the two) was 15.5 characters per second.

[edit]Teletypewriter-derived printersMain article: Teleprinter

The common teleprinter could easily be interfaced to the computer and became very popular except for those

computers manufactured byIBM. Some models used a "typebox" that was positioned, in the X- and Y-axes, by a

mechanism and the selected letter form was struck by a hammer. Others used a type cylinder in a similar way as

the Selectric typewriters used their type ball. In either case, the letter form then struck a ribbon to print the

letterform. Most teleprinters operated at ten characters per second although a few achieved 15 CPS.

[edit]Daisy wheel printersMain article: Daisy wheel printer

Daisy-wheel printers operate in much the same fashion as a typewriter. A hammer strikes a wheel with petals, the

"daisy wheel", each petal containing a letter form at its tip. The letter form strikes a ribbon of ink, depositing the ink

on the page and thus printing a character. By rotating the daisy wheel, different characters are selected for

printing. These printers were also referred to as letter-quality printers because, during their heyday, they could

produce text which was as clear and crisp as a typewriter, though they were nowhere near the quality ofprinting

presses. The fastest letter-quality printers printed at 30 characters per second.

[edit]Dot-matrix printersMain article: Dot matrix printer

In the general sense many printers rely on a matrix of pixels, or dots, that together form the larger image. However,

the term dot matrix printeris specifically used for impact printers that use a matrix of small pins to create precise

dots. The advantage of dot-matrix over other impact printers is that they can produce graphical images in addition

to text; however the text is generally of poorer quality than impact printers that use letterforms (type).

A Tandy 1000 HX with a Tandy DMP-133 dot-matrix printer.

Dot-matrix printers can be broadly divided into two major classes:

Ballistic wire printers (discussed in the dot matrix printers article)

Stored energy printers

Dot matrix printers can either be character-based or line-based (that is, a single horizontal series of pixels across

the page), referring to the configuration of the print head.

At one time, dot matrix printers were one of the more common types of printers used for general use, such as for

home and small office use. Such printers would have either 9 or 24 pins on the print head. 24-pin print heads were

able to print at a higher quality. Once the price of inkjet printers dropped to the point where they were competitive

with dot matrix printers, dot matrix printers began to fall out of favor for general use.

Some dot matrix printers, such as the NEC P6300, can be upgraded to print in colour. This is achieved through the

use of a four-colour ribbon mounted on a mechanism (provided in an upgrade kit that replaces the standard black

ribbon mechanism after installation) that raises and lowers the ribbons as needed. Colour graphics are generally

printed in four passes at standard resolution, thus slowing down printing considerably. As a result, colour graphics

can take up to four times longer to print than standard monochrome graphics, or up to 8-16 times as long at high

resolution mode.

Dot matrix printers are still commonly used in low-cost, low-quality applications like cash registers, or in

demanding, very high volume applications like invoice printing. The fact that they use an impact printing method

allows them to be used to print multi-part documents usingcarbonless copy paper, like sales invoices and credit

card receipts, whereas other printing methods are unusable with paper of this type. Dot-matrix printers are now (as

of 2005) rapidly being superseded even as receipt printers.

[edit]Line printersMain article: Line printer

Line printers, as the name implies, print an entire line of text at a time. Three principal designs existed. In drum

printers, a drum carries the entire character set of the printer repeated in each column that is to be printed. In chain

printers, also known as train printers, the character set is arranged multiple times around a chain that travels

horizontally past the print line. In either case, to print a line, precisely timed hammers strike against the back of the

paper at the exact moment that the correct character to be printed is passing in front of the paper. The paper

presses forward against a ribbon which then presses against the character form and the impression of the

character form is printed onto the paper.

Comb printers, also called line matrix printers, represent the third major design. These printers were a hybrid of dot

matrix printing and line printing. In these printers, a comb of hammers printed a portion of a row of pixels at one

time, such as every eighth pixel. By shifting the comb back and forth slightly, the entire pixel row could be printed,

continuing the example, in just eight cycles. The paper then advanced and the next pixel row was printed. Because

far less motion was involved than in a conventional dot matrix printer, these printers were very fast compared to

dot matrix printers and were competitive in speed with formed-character line printers while also being able to print

dot matrix graphics.

Line printers, better known as line matrix printers are widely used in the automotive, logistic and banking world for

high speed and barcodeprinting. They are known as robust and durable printers that have the lowest price per

page, label or other item. Printronix and TallyGenicomare among the leading manufacturers today.

Line printers were the fastest of all impact printers and were used for bulk printing in large computer centres. They

were virtually never used with personal computers and have now been replaced by high-speed laser printers. The

legacy of line printers lives on in many computeroperating systems, which use the abbreviations "lp", "lpr", or "LPT"

to refer to printers.

[edit]Pen-based plottersMain article: Plotter

A plotter is a vector graphics printing device which operates by moving a pen over the surface of paper. Plotters

have been used in applications such as computer-aided design, though they are rarely used now and are being

replaced with wide-format conventional printers, which nowadays have sufficient resolution to render high-quality

vector graphics using a rasterized print engine. It is commonplace to refer to such wide-format printers as

"plotters", even though such usage is technically incorrect. There are two types of plotters, flat bed and drum.

Printing mode

The data received by a printer may be:

A string of characters

A bitmapped image

A vector image

Some printers can process all three types of data, others not.

Character printers, such as daisy wheel printers, can handle only plain text data or rather simple point

plots.

Pen plotters typically process vector images. Inkjet based plotters can adequately reproduce all three.

Modern printing technology , such as laser printers and inkjet printers, can adequately reproduce all three.

This is especially true of printers equipped with support for PostScript and/or PCL; which includes the vast

majority of printers produced today.

Today it is common to print everything (even plain text) by sending ready bitmapped images to the printer,

because it allows better control over formatting.  Many printer drivers do not use the text mode at all, even if the

printer is capable of it.

[edit]Monochrome, colour and photo printers

A monochrome printer can only produce an image consisting of one colour, usually black. A monochrome printer

may also be able to produce various tones of that color, such as a grey-scale. A colour printer can produce images

of multiple colours. A photo printer is a colour printer that can produce images that mimic the colour range (gamut)

and resolution of prints made from photographic film. Many can be used on a standalone basis without a computer,

using a memory card or USB connector.

[edit]The printer manufacturing business

Often the razor and blades business model is applied. That is, a company may sell a printer at cost, and make

profits on the ink cartridge, paper, or some other replacement part. This has caused legal disputes regarding the

right of companies other than the printer manufacturer to sell compatible ink cartridges. To protect their business

model, several manufacturers invest heavily in developing new cartridge technology and patenting it.

Other manufacturers, in reaction to the challenges from using this business model, choose to make more money

on printers and less on the ink, promoting the latter through their advertising campaigns. Finally, this generates two

clearly different proposals: "cheap printer — expensive ink" or "expensive printer — cheap ink". Ultimately, the

consumer decision depends on their reference interest rate or their time preference. From

an Economics viewpoint, there is a clear trade-off between cost per copy and cost of the printer.[7]

[edit]Printing speed

The speed of early printers was measured in units of characters per second. More modern printers are measured

in pages per minute. These measures are used primarily as a marketing tool, and are not as well standardised

as toner yields. Usually pages per minute refers to sparse monochrome office documents, rather than dense

pictures which usually print much more slowly, especially colour images. PPM are most of the time referring to A4

paper in Europe and letter paper in the United States, resulting in a 5-10% difference.

Other printers

A number of other sorts of printers are important for historical reasons, or for special purpose uses:

Digital minilab  (photographic paper)

Electrolytic printers

Spark printer

Barcode printer  multiple technologies, including: thermal printing, inkjet printing, and laser

printing barcodes

Billboard / sign paint spray printers

Laser etching (product packaging) industrial printers

Microsphere (special paper)

MinilabFrom Wikipedia, the free encyclopedia

A Noritsu QSS-3301 digital minilab

A minilab is a small photographic developing and printing system, as opposed to large centralized photo

developing labs. Many retail stores use minilabs (or digital minilabs) to provide on-site photo finishing services.

With the increase in popularity of digital photography, the demand for film development has decreased. This

means that the larger labs capable of processing 30 or 40 thousand films a day are going out of business, and

more retailers are installing minilabs.

In Kodak and Agfa minilabs films are processed using C41b chemistry and the paper is processed using RA-4.

Using these chemical processes films can be ready for collection in as little as 20 minutes, depending on the

machine capabilities and the operator.

A typical minilab consists of two machines, a film processor and a paper printer/processor. In some installations, these two components are integrated into a single machine. In addition, some digital minilabs are also equipped with photo ordering kiosks.

Contents

 [hide]

1   Film processor

2   Photo printer

3   Industry changes

4   Digital minilab

5   See also

6   References

7   External links

[edit]Film processor

35 mm films are pulled, this means the end of the film is extracted from cassette. This can done manually or by

using a small machine that essentially uses tape to pull the film leader out of the cassette. In cases when the end

of the film cannot be removed or if the film is damaged, the film can be removed using a dark bag or a dark box. A

twin check number (a pair of sticker with a unique number) is put onto the film and the matching number onto the

film processing envelope, so that after processing this film can be easily identified to the customers envelope.

Films are spliced on the leader cards one or two at a time, to do this the end of the film is cut square, special

chemical restistant tape is used to attach the film to the leader card. The leader card(s) is/are then inserted into the

film processor and are fed through the machine using sprockets in the card. The film goes through a developer,

bleach, fix and stabiliser then through a dryer. After the film is processed it is cut from the leader card and re-united

with the processing envelope containing the customer details, from here the film goes forward for printing.

[edit]Photo printer

Most printer/processes are computer controlled. The front of the film is fed into the printing gate. Sensors see the

film and forward the film to the first frame. DX codes on the edge of the film are read by the printer and the film

channel is selected accordingly to give the optimum result. Each frame is printed one at a time, the photographic

paper is advanced each time and when there is sufficient frames printed the paper automatically advances into the

paper processor. The paper passes through a developer, bleach/fix, a wash, and dryer. The prints are then cut up

and are collected in a bundle. From here a smaller machine is used to cut the negatives into fours and sleeved to

protect them.

The final job is to put the negatives with the prints into a wallet and into the processing envelope. The order is then

priced and placed into a rack or draw waiting for the customer to collect.

[edit]Industry changes

By the end of 2005, two manufacturers, Agfa and Konica went out of business. Minilab Factory GmbH took over

the renowned minilab branch of Agfa in 2006. Gretag Imaging, not to be confused with former Gretag Macbeth,

went bankrupt in December, 2002. Subsequently, the minilab related assets were sold to the newly formed San

Marco Imaging. The wholesale lab related assets were sold to KIS Photo Me Group. In 2006, Noritsu and Fuji

announced a strategic alliance. [1] Noritsu now manufactures all of Fuji's minilab equipment [2]

[edit]Digital minilab

A digital minilab is a computer printer that uses traditional chemical photographic processes to make prints

from digital images. Photographs are input to the digital minilab using a built-in film scanner that captures images

from negative and positive photographic films (including mounted slides), flatbed scanners, a kiosk that

accepts CD-ROMs or memory cards from a digital camera, or a website that acceptsuploads. The operator can

make many corrections such as brightness or color saturation, contrast, scene lighting color correction, sharpness

and cropping. A laser, LCD/LED, or Micro Light Valve Array (MLVA) then exposes photographic paper with the

image, which is then processed by the minilab just as if it had been exposed from a negative.

The price of a digital minilab can reach up to $250,000 USD. The most popular brands

include KIS, Noritsu, Doli and Fuji..

Digital minilabs are generally too expensive for typical home use, but many retailers purchase or lease them to

offer photo printing services to their customers. The resulting photographs have the same quality and durability as

traditional photographs since the same chemical processes (e.g. RA-4) are used. This is often better than can be

achieved by typical home inkjet printers, and for smaller prints generally less expensive.

A new type of minilab is the dry lab, which does not require the use of developer or fixer chemicals, and does not

require moistening and then drying of the print. These machines are cheaper, smaller, and use inkjet printing

instead of a chemical developing process. This allows them to be installed in smaller retail stores, print shops, and

resort/tourist locations that could not justify an expensive, high throughput, wet minilab. Standard questions of

inkjet quality and longevity apply.

VT52From Wikipedia, the free encyclopedia

File:DEC,VT52.jpg

DEC VT52 atop its optional stand

DEC VT52 terminal

The VT52 was a CRT-based computer terminal produced by Digital Equipment Corporation introduced in

September, 1975 [1]. It provided a screen of 24 rows and 80 columns of text and supported all 95 ASCIIcharacters

as well as 32 graphics characters. It supported asynchronous communication at baud rates up to 9600 bits per

second and did not require any fill characters. The terminal also introduced a separate function keypad that

allowed "Gold Key" editing (as exemplified by WPS-8, KED, and EDT).

The VT52 offered an optional hard-copy device called an electrolytic copier. This device was able to print, scan-

line by scan-line, an exact replica of the screen onto a roll of paper that was saturated with salty water. (It did this

by electroplating metal from an electrode into the paper.) While it did an admirable job of capturing the contents of

the screen, the output of the copier had an unfortunate resemblance to wet toilet tissue [2] [3] . Digital patented the

innovation of having a single character generator provide the text font for both screen and copier.

[edit]Stages of development

The VT50 was the first terminal Digital produced in this cabinet. It provided only 12 lines of text (leading some

users to object to the "double-spacing") and, like the predecessor VT05, did not support lowercase letters.

Computer users of that era used coding in the rare case that they needed lowercase text. Opinion differed as to

whether the VT50 was to be a dry run for the engineers or a lucrative product. The introduction of the VT52, and its

support of lowercase text on the screen and scrolling both upward and downward, enabled WYSIWYG ("What you

see is what you get") text editing.

The large size of the cabinet was deliberate, to avoid a cooling fan. The two circuit boards with processor and

memory at the base of the terminal, and a single board with power-supply and monitor electronics at the rear, were

cooled by unforced air. The large, flat top of the terminal frequently accommodated large volumes of DEC

documentation.

These terminals used a primitive, custom central processing unit built from small-scale-integration integrated

circuits. It was so basic that addition and subtraction could only be done by repeatedly incrementing or

decrementing two registers, and only while a raster scan was not in progress. Moreover, the time taken by such a

program loop had to be nearly constant, or text lower on the screen would be displayed in the wrong place during

that refresh. Display of text was not done under microprogram control; the microprogram activated separate

hardware to take exclusive access to screen memory and waited until a line of pixels was complete.

The VT52 became a platform on which Digital built several related devices. The VT55 incorporated an add-on

graphics system that was capable of displaying two mathematical functions or histograms.

The VT61 and VT62 were block-mode terminals optimized for typesetting applications. They used the same

cabinet but had a more complete custom processor. Application-specific behavior was coded in

separate PROM memory, using a separate instruction code that the processor interpreted. This unpublished

language was to be used to easily develop additional models specific to single Digital marketing organizations.

These terminals synthesized a "tock" sound on a speaker for feedback when a key was pressed, whereas the

VT5x activated a relay. Though the keyboards were identical, VT6x users admired the superior "feel."

The VT78 added to the VT52 a single-chip PDP-8 processor, on which was programmed WPS-8, Digital's word

processing system. This model was not a terminal to use to communicate with a computer, but a complete, stand-

alone system. Whereas the VT50 was developed in the era before it was common to apply computers to text, the

VT78 was a product designed for that application.

Spark printerFrom Wikipedia, the free encyclopedia

The Sinclair ZX Printer, a small spark printer for the ZX81 and ZX Spectrum computers

A spark printer is an obsolete form of computer printer which uses a special papercoated with a layer

of aluminium over a black backing, which is printed on by using a pulsing current onto the paper via two styli that

move across on a moving belt at high speed. They were introduced in the late 1960s. Such devices were

sometimes incorrectly referred to as thermal printers (which is in fact a different technology.)

Spark printing was a simple and inexpensive technology. The print quality was relatively poor, but at a time when conventional printers cost hundreds of pounds, spark printers' sub-£100 price was a major selling point. The other major downside is that they can only print onto special metallised paper; such paper is no longer readily available.

Contents

 [hide]

1   Models

2   Variants

3   References

4   External links

[edit]Models

The Sinclair ZX Printer, introduced in November 1981 for the low-end ZX81 (and later ZX Spectrum) home

computers used the spark printing method, and retailed for £49.95.

In the early 1980s, Casio released a "Mini Electro Printer", the FP-10 for some of their scientific calculators.[1]

The Hewlett Packard 9120A, which attached to the top of the HP-9100A/B calculator, also used the sparking

technique.

[edit]Variants

A different spark printer implementation propelled dry toner from a tiny hole in the end of a glass rod, using a high-

voltage spark between the platen and print head. The glass toner rod held a solid mass of toner, pushed toward

the ejection tip by a spring. This had the advantage of printing onto plain paper, but the disadvantage of the toner

not being cured to the paper, and thus easily smudged. Unlike the Sinclair printer, this printer had only one stylus

(the toner rod), since the entire platen behind the paper served as the other spark electrode. The printer could only

print one line of pixels at a time.

Barcode printerFrom Wikipedia, the free encyclopedia

A barcode printer

A barcode printer (or bar code printer) is a computer peripheral for printing barcode labels or tags that can be

attached to physical objects. Barcode printers are commonly used to label cartons before shipment, or to label

retail items with UPCs or EANs.

The most common barcode printers employ one of two different printing technologies. Direct thermal printers use a

printhead to generate heat that causes a chemical reaction in specially designed paper that turns the paper

black. Thermal transfer printers also use heat, but instead of reacting the paper, the heat melts a waxy or resin

substance on a ribbon that runs over the label or tag material. The heat transfers ink from the ribbon to the paper.

Direct thermal printers are generally less expensive, but they produce labels that can become illegible if exposed

to heat, direct sunlight, or chemical vapors.

Barcode printers are designed for different markets. Industrial barcode printers are used in large warehouses and

manufacturing facilities. They have large paper capacities, operate faster and have a longer service life. For retail

and office environments, desktop barcode printers are most common.

Label printerFrom Wikipedia, the free encyclopedia

This article does not cite any references or sources.Please help improve this article by adding citations to reliable sources. Unsourced material may be challenged andremoved. (December 2009)

A label printer is a computer printer that prints on self-adhesive label material and/or card-stock (tags). Label

printers with built-in keyboards and displays, for stand-alone use (without a computer), are often called label

makers. Label printers are different from ordinary printers because they need to have special feed mechanisms to

handle rolled stock, or tear sheet (fanfold) stock. Common connectivity for label printers include RS-

232 serial, Universal Serial Bus (USB), parallel, Ethernet and various kinds of wireless.

Label printers have a wide variety of applications, including supply chain management, retail price

marking, packaging labels, blood and laboratory specimen marking, and fixed assets management.

[edit]Mechanisms

Brother P-Touch 540 label printer

Label printers use a wide range of label materials, including paper and synthetic polymer ("plastic") materials.

Several types of print mechanisms are also used, including laser and impact, but thermal printer mechanisms are

probably the most common. Two types of thermal printer are seen:

Direct Thermal - Uses heat sensitive paper (similar to thermal fax paper). Direct thermal labels tend to

fade over time (typically 6 to 12 months); if exposed to heat, direct sunlight or chemical vapors, the life is

shortened. Therefore, direct thermal labels are primarily used for short duration applications, such as shipping

labels.

Thermal Transfer - Uses heat to transfer ink from ribbon onto the label for a permanent print. Some

thermal transfer printers are also capable of direct thermal printing.

There are three grades of ribbon for use with a thermal transfer printers:

Wax is the most popular with some smudge resistance, and is suitable for matte and semi-gloss paper

labels.

Wax / Resin is smudge resistant, suitable for semi-gloss paper and some synthetic labels.

Resin is scratch and chemical resistant, suitable for coated synthetic labels.

When printing on continuous label stock, there is a tendency for the print location to shift slightly from label to label.

To ensure registration of the print area with the target media, many label printers use a sensor that detects a gap,

notch, line or perforation between labels. This allows the printer to adjust the intake of label stock so that the print

aligns correctly with the media.

[edit]Types of label printers

Desktop label printers are usually designed for light- to medium-duty use with a roll of stock up to 4"

wide. They are quiet and inexpensive.

Commercial label printers can typically hold a larger roll of stock (up to 8" wide) and are geared for

medium-volume printing.

Industrial label printers are designed for heavy-duty, continuous operation in warehouses, distribution

centers and factories.

Industrial portable label printers are designed for heavy-duty operation on location. Examples of

applications are labeling for electrical installations, construction sites, production floors where there are no

computers.

RFID  readers are specialized label printers that print and encode at the same time on RFID

transponders (tags) enclosed in paper or printable synthetic materials. RFID tags need to have printed

information for backwards compatibility with barcode systems, so humans can identify the tag.

Label printer applicators are designed to automate the labeling process. These systems are common

in manufacturing and warehousing facilities that require cases and pallets to be labeled for shipping.

Label software is computer software which runs on a general-purpose personal computer, and is

designed to create and/or format labels for printing. The software can use native OS printer drivers, or embed

drivers in the software, bypassing the OS print subsystem. It may work with dedicated label printers as

described in this article, or use sheet- or continuous-fed labels in a general-purpose computer printer.

An electronic label maker, depicting buttons, LCD screen, and sample thermal label.

Personal label printers or label makers are handheld or small desktop devices. They are intended for home office, small office, or small business use. The cost of the printers is generally very low, making them popular with low volume users; but they print on special tapes, oftenthermal, which are usually expensive. In the past, mechanical systems which worked by embossing a colored plastic tape, called embossing tape, were common. A hammer in the shape of the letter caused a

letter-shaped extrusion on the opposite side of the tape. The raised plastic would discolor, providing visual contrast. Today, this type has been almost completely displaced by electronic thermal transfer devices with built-in keyboard and display, and an integrated cartridge containing the label material (and print ribbon, if used).

Thermal printerFrom Wikipedia, the free encyclopedia

  (Redirected from Thermal printing)

For the type of printer which uses sparks and aluminised paper (and is sometimes referred to as a

"thermal printer"), see spark printer.

Part of the series on theHistory of printing

Woodblock printing 200

Movable type 1040

Printing press 1454

Lithography 1796

Laser printing 1969

Thermal printing circa 1972

A thermal printer (or direct thermal printer) produces a printed image by selectively heating

coatedthermochromic paper, or thermal paper as it is commonly known, when the paper passes over the

thermalprint head. The coating turns black in the areas where it is heated, producing an image. Two-color

direct thermal printers can print both black and an additional color (often red) by applying heat at two

differenttemperatures.

Thermal transfer printing is a related method that uses a heat-sensitive ribbon instead of heat-sensitive

paper[1].

Contents

 [hide]

1   Essential mechanisms

2   Applications

3   Health concerns

4   References

5   See also

[edit]Essential mechanisms

A thermal printer comprises these key components:

Thermal head — generates heat; prints on paper

Platen — a rubber roller that feeds paper

Spring — applies pressure to the thermal head, causing it to contact the thermo-sensitive paper

Controller boards — for controlling the mechanism

In order to print, thermo-sensitive paper is inserted between the thermal head and the platen. The printer

sends an electrical current to theheating elements of the thermal head, which generate heat. The heat

activates the thermo-sensitive coloring layer of the thermo-sensitive paper, which changes color where

heated. Such a printing mechanism is known as a thermal system or direct system. The heating elements

are usually arranged as a matrix of small closely-spaced dots—thermal printers are actually dot-matrix

printers, though they are not so called.

The paper is impregnated with a solid-state mixture of a dye and a suitable matrix; a combination of

a fluoran leuco dye and anoctadecylphosphonic acid is an example. When the matrix is heated above its

melting point, the dye reacts with the acid, shifts to its colored form, and the changed form is then conserved

in metastable state when the matrix solidifies back quickly enough. See thermochromism.

Controller boards are embedded with firmware to manage the thermal printer mechanisms.

The Firmware can manage multiple bar code types, graphics and logos. They enable the user to choose

between different resident fonts (also including Asian fonts) and character sizes.

Controller boards can drive various sensors such as paper low, paper out, door open, top of form etc., and

they are available with a variety of interfaces, such as RS-232, parallel, USB and wireless. For point of

sale application some boards can also control the cash drawer.

[edit]Applications

Thermal printers print more quietly and usually faster than impact dot matrix printers. They are also smaller,

lighter and consume less power, making them ideal for portable and retail applications. Cost of thermal

paper, their only consumable, was somewhat less than US$0.10 per sheet as of 2010[2]. By comparison, one

study of the per page cost of color inkjet printers [3] found cost of third-party ink cartridge and paper to be

about $0.05 per page (some low-capacity cartridges are more expensive to use). Roll-based printers can be

rapidly refilled. Commercial applications of thermal printers include filling station pumps,

information kiosks, point of sale systems, voucher printers in slot machines,print on demand labels for

shipping and products, and for recording live rhythm strips on hospital cardiac monitors.

Through the 1990s many fax machines used thermal printing technology. Toward the beginning of the 21st

century, however, thermal wax transfer, laser, and inkjet printing technology largely supplanted thermal

printing technology in fax machines, allowing printing on plain paper.

The Game Boy Printer, made in 1998, was a small thermal printer used to print out certain elements from

some Game Boy games.

Early formulations of the thermo-sensitive coating used in thermal paper were sensitive to incidental

heat, abrasion, friction (which can cause heat, thus darkening the paper), light (which can fade printed

images), and water. Later thermal coating formulations are far more stable; theoretically, thermally-printed

text should remain legible at least 50 years[citation needed].

Hospitals commonly record fetal ultrasound scan images on thermal paper. This can cause problems if the

parents wish to preserve the image by laminating it, as the heat of most laminators will darken the entire

page—this can be tested for beforehand on an unimportant thermal print. An option is to make and laminate

a permanent ink duplicate of the image.

[edit]Health concerns

Reports began surfacing of studies in the 2000s finding the oestrogen-related chemical Bisphenol A ("BPA")

mixed in with thermal (and some other) papers. While the health concerns are very uncertain, various health

and science oriented political pressure organizations such as theEnvironmental Working Group have

pressed for these versions to be pulled from market. [4] [5]

Inkjet printerFrom Wikipedia, the free encyclopedia

  (Redirected from Inkjet printing)This article may contain original research. Please improve it by verifying the claims made and adding references. Statements consisting only of original research may be removed. More details may be available on the talk page. (August 2009)

This article needs additional citations for verification.Please help improve this article by adding reliable references. Unsourced material may be challenged and removed.(September 2007)

Laptop-sized Canon BJ-10v Lite introduced in 1993. It has the same appearance as the first Canon inkjet printer, the BJ-10v

introduced in 1990. The inner cover with setting instructions is also displayed.

An Epson inkjet printerPart of the series on the

History of printing

Woodblock printing 200

Movable type 1040

Printing press 1454

Lithography 1796

Laser printing 1969

Thermal printing circa 1972

An inkjet printer is a type of computer printer that creates a digital image by propelling variable-sized droplets of

ink onto paper. Inkjet printers are the most commonly used type of printer[1] and range from small inexpensive

consumer models to very large professional machines.[2]

The concept of inkjet printing originated in the 19th century, and the technology was first developed in the early

1950s. Starting in the late 1970s inkjet printers that could reproduce digital images generated by computers were

developed, mainly by Epson, Hewlett-Packard and Canon. In the worldwide consumer market, four manufacturers

account for the majority of inkjet printer sales: Canon, HP, Epson, and Lexmark, a 1991 spin-off from IBM.[citation

needed]

The emerging ink jet material deposition market also uses inkjet technologies, typically piezoelectriccrystals, to deposit materials directly on substrates.

Contents

 [hide]

1   Technologies

o 1.1   Continuous inkjet

o 1.2   Thermal/thermal DOD inkjet

o 1.3   Piezoelectric/piezoelectric DOD inkjet

2   Inkjet Inks

3   Inkjet head design

o 3.1   Fixed head

o 3.2   Disposable head

4   Cleaning mechanisms

o 4.1   Print quality

5   Inkjet advantages

6   Inkjet disadvantages

o 6.1   Third-party ink and cartridges

o 6.2   Overall expense

o 6.3   Continuous ink system

7   Underlying business model

8   Professional inkjet printers

9   Inkjet printing of functional materials

10   Inkjet trade names

11   See also

12   References

13   External links

[edit]Technologies

There are two main technologies in use in contemporary inkjet printers: continuous (CIJ) and Drop-on-Demand

(DOD). Drop-on-demand is further divided into thermal DOD and piezoelectric DOD

[edit]Continuous inkjet

The continuous inkjet method is used commercially for marking and coding of products and packages. The idea

was first patented in 1867, by Lord Kelvin and the first commercial devices (medical strip chart recorders) were

introduced in 1951 by Siemens.[3]

In continuous inkjet technology, a high-pressure pump directs liquid ink from a reservoir through a gunbody and a

microscopic nozzle, creating a continuous stream of ink droplets via the Plateau-Rayleigh instability. A

piezoelectric crystal creates an acoustic wave as it vibrates within the gunbody and causes the stream of liquid to

break into droplets at regular intervals – 64,000 to 165,000 droplets per second may be achieved. The ink droplets

are subjected to an electrostatic field created by a charging electrode as they form; the field varies according to the

degree of drop deflection desired. This results in a controlled, variable electrostatic charge on each droplet.

Charged droplets are separated by one or more uncharged “guard droplets” to minimize electrostatic repulsion

between neighbouring droplets.

The charged droplets pass through an electrostatic field and are directed (deflected) by electrostatic deflection

plates to print on the receptor material (substrate), or allowed to continue on undeflected to a collection gutter for

re-use. The more highly charged droplets are deflected to a greater degree. Only a small fraction of the droplets is

used to print, the majority being recycled.

Continuous ink jet is one of the oldest ink jet technologies in use and is fairly mature. The major advantages are

the very high velocity (~50 m/s) of the ink droplets, which allows for a relatively long distance between print head

and substrate, and the very high drop ejection frequency, allowing for very high speed printing. Another advantage

is freedom from nozzle clogging as the jet is always in use, therefore allowing volatile solvents such

as ketones and alcohols to be employed, giving the ink the ability to "bite" into the substrate and dry quickly.

The ink system requires active solvent regulation to counter solvent evaporation during the time of flight (time

between nozzle ejection and gutter recycling) and from the venting process whereby air that is drawn into the

gutter along with the unused drops is vented from the reservoir. Viscosity is monitored and a solvent (or solvent

blend) is added to counteract solvent loss.

[edit]Thermal/thermal DOD inkjet

Most consumer inkjet printers, from companies including Canon, Hewlett-Packard, and Lexmark (but not Epson),

use print cartridges with a series of tiny chambers each containing a heater, all of which are constructed

by photolithography. To eject a droplet from each chamber, a pulse of current is passed through the heating

element causing a rapid vaporisation of the ink in the chamber to form a bubble, which causes a large pressure

increase, propelling a droplet of ink onto the paper (hence Canon's tradename of Bubble Jet). The ink's surface

tension, as well as the condensation and thus contraction of the vapor bubble, pulls a further charge of ink into the

chamber through a narrow channel attached to an ink reservoir.

The inks used are usually water-based (aqueous) and use either pigments or dyes as the colourant. The inks used

must have a volatile component to form the vapour bubble, otherwise droplet ejection cannot occur. As no special

materials are required, the print head is generally cheaper to produce than in other inkjet technologies. The

thermal inkjet principle was discovered by Canon engineer Ichiro Endo in August 1977.

Thermal inkjet printers are not the same as thermal printers, which produce images by heating thermal paper, as

seen on older fax machines, cash registers, ATM receipt printers, and lottery ticket printers.

[edit]Piezoelectric/piezoelectric DOD inkjet

Most commercial and industrial inkjet printers and some consumer printers (those produced by Epson) use

a piezoelectric material in an ink-filled chamber behind each nozzle instead of a heating element. When a voltage

is applied, the piezoelectric material changes shape, which generates a pressure pulse in the fluid forcing a droplet

of ink from the nozzle. Piezoelectric (also called Piezo) inkjet allows a wider variety of inks than thermal inkjet as

there is no requirement for a volatile component, and no issue with kogation, but the print heads are more

expensive to manufacture due to the use of piezoelectric material (usually PZT, lead zirconium titanate). Piezo

inkjet technology is often used on production lines to mark products - for instance the use-before date is often

applied to products with this technique; in this application the head is stationary and the product moves past.

Requirements of this application are a long service life, a relatively large gap between the print head and the

substrate, and low operating cost. There is a drop-on-demand process, with software that directs the heads to

apply between zero to eight droplets of ink per dot and only where needed. As of June 2009, the fastest cut-sheet

inkjet printer on the market is the RISO ComColor 9050, which prints 146 USLetter and 150 A4 full-color pages per

minute in both one-sided and two-sided printing modes.[4][5]Recent developments of the inkjet extend the operation

from printing into manufacturing processes. The newest of these technologies is to deposit layers of plastic

material as digital embossing over the top of printed works.[6]

[edit]Inkjet Inks

The basic problem with inkjet inks are the conflicting requirements for a coloring agent that will stay on the surface

and rapid dispersement of the carrier fluid.

Desktop inkjet printers, as used in offices or at home, tend to use aqueous inks based on a mixture of water,

glycol and dyes or pigments. These inks are inexpensive to manufacture, but are difficult to control on the surface

of media, often requiring specially coated media. HP inks contain sulfonated polyazo black dye (commonly used

for dying leather), nitrates and other compounds. Aqueous inks are mainly used in printers with thermal inkjet

heads, as these heads require water to perform.

While aqueous inks often provide the broadest color gamut and most vivid color, most are not waterproof without

specialized coating orlamination after printing. Most Dye-based inks, while usually the least expensive, are subject

to rapid fading when exposed to light. Pigment-based aqueous inks are typically more costly but provide much

better long-term durability and ultraviolet resistance. Inks marketed as “Archival Quality” are usually pigment-

based.

Some professional wide format printers use aqueous inks, but the majority in professional use today employ a

much wider range of inks, most of which require piezo inkjet heads and extensive maintenance:

Solvent inks: the main ingredient of these inks are volatile organic compounds (VOCs), organic

chemical compounds that have highvapor pressures. Color is achieved with pigments rather than dyes for

excellent fade-resistance. The chief advantage of solvent inks is that they are comparatively inexpensive and

enable printing on flexible, uncoated vinyl substrates, which are used to produce vehicle graphics, billboards,

banners and adhesive decals. Disadvantages include the vapour produced by the solvent and the need to

dispose of used solvent. Unlike most aqueous inks, prints made using solvent-based inks are generally

waterproof and ultraviolet-resistant (for outdoor use) without special over-coatings. The high print speed of

many solvent printers demands special drying equipment, usually a combination of heaters and blowers. The

substrate is usually heated immediately before and after the print heads apply ink. Solvent inks are divided

into two sub-categories:

Hard solvent ink offers the greatest durability without specialized over-coatings but requires

specialized ventilation of the printing area to avoid exposure to hazardous fumes.

Mild or "Eco" solvent inks, while still not as safe as aqueous inks, are intended for use in

enclosed spaces without specialized ventilation of the printing area. Mild solvent inks have rapidly gained

popularity in recent years as their color quality and durability have increased while ink cost has dropped

significantly.[7]

UV-curable inks: these inks consist mainly of acrylic monomers with an initiator package. After printing,

the ink is cured by exposure to strong UV-light. The advantage of UV-curable inks is that they "dry" as soon

as they are cured, they can be applied to a wide range of uncoated substrates, and they produce a very

robust image. Disadvantages are that they are expensive, require expensive curing modules in the printer,

and the cured ink has a significant volume and so gives a slight relief on the surface. Though improvements

are being made in the technology, UV-curable inks, because of their volume, are somewhat susceptible to

cracking if applied to a flexible substrate. As such, they are often used in large "flatbed" printers, which print

directly to rigid substrates such as plastic, wood or aluminum where flexibility is not a concern.

UV Curable Ink Properties and Functions:

• Photoinitiators: Absorb the UV energy from the light source on the print head. Chemical reaction occurs that

converts the liquid ink into a solid film.

• Monomers: Used as solvents because of their ability to reduce viscosity (thickness) and combine with other ink

components. 100% percent solids and do not release VOCs (volatile organic compounds). Monomers also add

improved film hardness and resistance properties.

• Oligomers: Determine the final properties of the cured ink film, including its elasticity, outdoor performance

characteristics and chemical resistance.

• Colorants: Can be dye-based or pigment-based. Usually, pigment-based because of the greater light fastness

and durability of pigments compared with dyes. Pigments used in outdoor advertising and display applications

have similar requirements to those used in automotive paints. Consequently, there is some crossover of use. While

a pigment is selected on the basis of the required application, size control and reduction along with dispersion

technique are major components of ink formulation.

UV Ink Printing Process:

1. Ink is exposed to UV radiation where a chemical reaction takes place where the photo-initiators cause

the ink components to cross-link into a solid.

2. Typically a shuttered mercury-vapor lamp is on either side of the print head, and produces a great

amount of heat to complete the curing process (this lamp is used for free radical UV ink, which is what

the majority of flatbed inkjet systems use).

3. UV inks do not evaporate, but rather cure or set as a result from this chemical reaction.

4. No material is evaporated or removed, which means about 100% of the delivered volume is used to

provide coloration.

5. This reaction happens very quickly, which leads to instant drying that results in a completely cured

graphic in a matter of seconds. This also allows for a very fast print process.

6. As a result of this instant chemical reaction no solvents penetrate the substrate once it comes off the

printer, which allows for high quality prints.

[8] [9]

Dye sublimation inks: these inks contain special sublimation dyes and are used to print directly or

indirectly on to fabrics which consist of a high percentage of polyester fibres. A heating step causes the dyes

to sublimate into the fibers and create an image with strong color and good durability.

[edit]Inkjet head design

Inkjet heads:

Disposable head (left) and

Fixed head (right) with ink cartridge (middle)

There are two main design philosophies in inkjet head design: fixed-head and disposable head. Each has its own

strengths and weaknesses. Most inkjets are used for photo printing.

[edit]Fixed head

The fixed-head philosophy provides an inbuilt print head (often referred to as a Gaither Head) that is designed to

last for the life of the printer. The idea is that because the head need not be replaced every time the ink runs out,

consumable costs can be made lower and the head itself can be more precise than a cheap disposable one,

typically requiring no calibration. On the other hand, if a fixed head is damaged, obtaining a replacement head can

become expensive if removing and replacing the head is even possible. If the printer's head cannot be removed,

the printer itself will then need to be replaced.

Fixed head designs are available in consumer products but are more likely to be found on industrial high-end

printers and large format plotters. In the consumer space, fixed-head printers are manufactured primarily by Epson

and Canon. Hewlett-Packard also offers a few fixed-head models, such as the HP Photosmart 3310. Industrial

fixed-head print heads are manufactured by these companies: Kodak Versamark, Trident, Xaar, Spectra (Dimatix),

Hitachi / Ricoh, HP Scitex, Brother, Konica Minolta, Seiko Epson, and ToshibaTec (a licensee of Xaar)[citation needed].

[edit]Disposable head

The disposable head philosophy uses a print head which is supplied as a part of a replaceable ink cartridge.

Every time a cartridge is exhausted, the entire cartridge and print head are replaced with a new one. This adds to

the cost of consumables and makes it more difficult to manufacture a high-precision head at a reasonable cost, but

also means that a damaged print head is only a minor problem: the user can simply buy a new cartridge. Hewlett-

Packard has traditionally favoured the disposable print head, as did Canon in its early models. This type of

construction can also be seen as an effort by printer manufacturers to stem third party ink cartridge assembly

replacements, as these would-be suppliers don't have the ability to manufacture specialized print heads.

An intermediate method does exist: a disposable ink tank connected to a disposable head, which is replaced

infrequently (perhaps every tenth ink tank or so). Most high-volume Hewlett-Packard inkjet printers use this setup,

with the disposable print heads used on lower volume models.

Canon now uses (in most models) replaceable print heads which are designed to last the life of the printer, but can

be replaced by the user if they should become clogged. For models with "Think Tank" technology, the ink tanks are

separate for each ink color.

[edit]Cleaning mechanisms

The primary cause of inkjet printing problems is due to ink drying on the printhead's nozzles, causing the pigments

and dyes to dry out and form a solid block of hardened mass that plugs the microscopic ink passageways. Most

printers attempt to prevent this drying from occurring by covering the printhead nozzles with a rubber cap when the

printer is not in use. Abrupt power losses, or unplugging the printer before it has capped the printhead, can cause

the printhead to be left in an uncapped state. Further even when capped this seal is not perfect, and over a period

of several weeks the moisture can still seep out, causing the ink to dry and harden. Once ink begins to collect and

harden drop volume can be affected, drop trajectory can change, or the nozzle can fail to jet ink completely.

To combat this drying, nearly all inkjet printers include a mechanism to reapply moisture to the printhead. Typically

there is no separate supply of pure ink-free solvent available to do this job, and so instead the ink itself is used to

remoisten the printhead. The printer attempts to fire all nozzles at once, and as the ink sprays out, some of it wicks

across the printhead to the dry channels and partially softens the hardened ink. After spraying, a rubber wiper

blade is swept across the printhead to spread the moisture evenly across the printhead, and the jets are again all

fired to dislodge any ink clumps blocking the channels.

Some use a supplemental air-suction pump, utilizing the rubber capping station to suck ink through a severely

clogged cartridge. The suction pump mechanism is frequently driven by the page feed stepper motor – it is

connected to the end of the shaft. The pump only engages when the shaft turns backwards, hence the rollers

reversing while head cleaning. Due to the built-in head design, the suction pump is also needed to prime the ink

channels inside a new printer, and to reprime the channels between ink tank changes.

Professional solvent- and UV-curable ink wide-format inkjet printers generally include a "manual clean" mode that

allows the operator to manually clean the print heads and capping mechanism and to replace the wiper blades and

other parts used in the automated cleaning processes. The volume of ink used in these printers often leads to

"overspray" and therefore buildup of dried ink in many places that automated processes are not capable of

cleaning.

The ink consumed in the cleaning process needs to be collected to prevent ink from leaking in the printer. The

collection area is called thespittoon, and in Hewlett Packard printers this is an open plastic tray underneath the

cleaning/wiping station. In Epson printers, there is typically a large absorption pad in a pan underneath the paper

feed platen. For printers several years old, it is common for the dried ink in the spittoon to form a pile that can stack

up and touch the printheads, jamming the printer. Some larger professional printers using solvent inks may employ

a replaceable plastic receptacle to contain waste ink and solvent which must be emptied or replaced when full.

The type of ink used in the printer can also affect how quickly the printhead nozzles become clogged. While the

OEM ink is engineered to match the printer mechanism, generic inks cannot exactly match the composition of the

OEM since the ink composition is a trade secret. Generic ink brands may alternately be too volatile to keep the

printhead moist during storage, or may be too thick and jellied leading to frequent printhead channel clogging.

Labyrinth air vent tubes on the top of an Epson Stylus Photo 5-color ink tank. The long air channels are molded into the top of the

tank and the blue label seals the channels into long tubes. The yellow label is removed prior to installation, and opens the tube

ends to the atmosphere so that ink can be sprayed onto the paper. Removing the blue label would destroy the tubes and cause

the moisture to quickly evaporate.

There is a second type of ink drying that most printers are unable to prevent. For ink to spray from the cartridge, air

must enter to displace the removed ink. The air enters via an extremely long, thin labyrinth tube, up to 10 cm long,

wrapping back and forth across the ink tank. The channel is long and narrow to reduce moisture evaporation

through the vent tube, but some evaporation still occurs and eventually the ink cartridge dries up from the inside

out. To combat this problem, which is especially acute with professional fast-drying solvent inks, many wide-format

printer cartridge designs contain the ink in an airtight, collapsible bag that requires no vent. The bag merely shrinks

until the cartridge is empty.

The frequent cleaning conducted by printers can consume quite a bit of ink and has a great impact on cost per

page determinations.

Clogged nozzles can be detected by printing a pattern on the page. Methods are known for re-routing printing

information from a clogged nozzle to a working nozzle.[citation needed]

[edit]Print quality

A method to quantify the spatial resolution of printed inkjet images is described in Tunable Laser Applications.

[10] This method consists in printing transmission gratings with the inkjet printer to be assessed and measuring the

modulation of laser light in an N-Slit interferometer. For gratings with spatial frequencies in the 0.25-5.0 lines/mm

range, modulations in the 0.71-0.87 range are reported for various printers.[10] The closer the measured modulation

is to unity (~ 1.0) the higher the spatial resolution of the print.

[edit]Inkjet advantages

This section does not cite any references or sources.Please help improve this article by adding citations to reliable sources. Unsourced material may be challenged andremoved. (May 2010)

Compared to earlier consumer-oriented color printers, inkjets have a number of advantages. They are quieter in

operation than impact dot matrix or daisywheel printers. They can print finer, smoother details through higher

printhead resolution, and many consumer inkjets with photographic-quality printing are widely available.

In comparison to more expensive technologies like thermal wax, dye sublimations, and laser printers, inkjets have

the advantage of practically no warm up time and lower cost per page (except when compared to laser printers).

For some inkjet printers, monochrome ink sets are available either from the printer manufacturer or third-party

suppliers. These allow the inkjet printer to compete with the silver-based photographic papers traditionally used in

black-and-white photography, and provide the same range of tones – neutral, "warm" or "cold". When switching

between full-color and monochrome ink sets, it is necessary to flush out the old ink from the print head with

a cleaning cartridge.

[edit]Inkjet disadvantages

Inkjet printers may have a number of disadvantages:

1. The ink is often very expensive. (For a typical OEM cartridge priced at $15, containing 5 mL of ink, the

ink effectively costs $3000 per liter—or $8000 per gallon.) According to the BBC (2003), "The cost of ink

has been the subject of an Office of Fair Tradinginvestigation. Which?   magazine  has accused

manufacturers of a lack of transparency about the price of ink and called for an industry standard for

measuring ink cartridge performance".[11]

2. Many "intelligent" ink cartridges contain a microchip that communicates the estimated ink level to the

printer; this may cause the printer to display an error message, or incorrectly inform the user that the ink

cartridge is empty. In some cases, these messages can be ignored, but some inkjet printers will refuse

to print with a cartridge that declares itself empty, to prevent consumers from refilling cartridges.

Thus, Epson embeds a chip which prevents printing when the chip claims the cartridge is empty,

although a researcher who over-rode the system found that in one case he could print up to 38% more

good quality pages, even though the chip stated that the cartridge was empty.[11]

3. The lifetime of inkjet prints produced by inkjets using aqueous inks is limited; they will eventually fade and

the color balance may change. On the other hand, prints produced from solvent-based inkjets may last

several years before fading, even in direct sunlight, and so-called "archival inks" have been produced for

use in aqueous-based machines which offer extended life.

4. Because the ink used in most consumer inkjets is water-soluble, care must be taken with inkjet-printed

documents to avoid even the smallest drop of water, which can cause severe "blurring" or "running."

Similarly, water-based highlighter markers can blur inkjet-printed documents.

5. The very narrow inkjet nozzles are prone to clogging. The ink consumed cleaning them - either during

cleaning invoked by the user, or in many cases, performed automatically by the printer on a routine

schedule - can account for a significant proportion of the ink used in the machine.

These disadvantages have been addressed in a variety of ways:

1. Third-party ink suppliers sell ink cartridges at significant discounts (at least 10%−30% of OEM cartridge

prices, sometimes up to 80%), and also bulk ink and cartridge self-refill kits at even lower prices.

2. Many vendors' "intelligent" ink cartridges have been reverse-engineered. It is now possible to buy

inexpensive devices to reliably reset such cartridges to report themselves as full, so that they may be

refilled many times.

3. Print lifetime is highly dependent on the quality and formulation of the ink as well as the paper chosen.

The earliest inkjet printers, intended for home and small office applications, used dye-based inks. Even

the best dye-based inks are not as durable as pigment-based inks, which are now available for many

inkjet printers.

4. Some inkjet printers now utilize pigment based ink, which is water insoluble.

5. Inkjet nozzles may be cleaned and unclogged by soaking in shallow water for 1 minute.

[edit]Third-party ink and cartridges

The high cost of OEM ink cartridges and the intentional obstacles to refilling them have been addressed by the

growth of third-party ink suppliers. Many printer manufacturers discourage customers from using third-party inks,

stating that they can damage the print heads due to not being the same formulation as the manufacturers' inks,

cause leaks, and produce inferior-quality output (e.g. of incorrect color gamut).Consumer Reports has noted that

third-party cartridges may contain less ink than OEM cartridges, and thus yield no cost savings, [12] whileWilhelm

Imaging Research [13]  claims that with third-party inks the lifetime of prints may be considerably reduced. However,

an April 2007 review[14] showed that, in a double-blind test, reviewers generally preferred the output produced using

third-party ink over OEM ink. In general, OEM inks have undergone significant system reliability testing with the

cartridge and print-head materials, whereas R&D efforts on 3rd party inks’ material compatibility is likely to be

significantly less. Some inkjet manufacturers have tried to prevent cartridges being refilled using various schemes

including fitting smart chips to the cartridges that can detect when the cartridge has run out of ink and prevent the

operation of a refilled cartridge.

The Magnuson–Moss Warranty Act is a US federal law that states that warrantors can not require that only brand

name parts be used with any product, as some printer manufacturers imply. However, the warranty can still be

voided if the warrantor can show that the failure was caused by the use of third-party components.

[edit]Overall expense

Inkjet printers cost less than laser printers, but their costlier ink cartridges means that the ink cost per page is

higher. As a result, inkjet printers tend to be more economical in low-volume printing applications, while laser

printers tend to be more economical for medium- to high-volume applications.

Inkjet printers are usually preferred in the home or for applications that require photo-realistic reproduction. Laser

printers are usually preferred in an office environment with higher printing volume.

[edit]Continuous ink system

Main article: Continuous ink system

[edit]Underlying business model

Microchips from Epson ink cartridges. These are tinyprinted circuit boards; a deposit of black epoxy covers the chip itself.

A common business model for inkjet printers involves selling the actual printer at or below production cost, [15]while

dramatically marking up the price of the (proprietary) ink cartridges (a model called "Freebie marketing"). All

current inkjet printers attempt to enforce this product tying using microchips in the cartridges to hinder the use of

third-party or refilled ink cartridges. The microchips monitor usage and report the ink remaining to the printer.

Some manufacturers also impose "expiration dates". When the chip reports that the cartridge is empty (or out of

date) the printer stops printing. Even if the cartridge is refilled, the microchip will indicate to the printer that the

cartridge is depleted. For many models (especially from Canon), the 'empty' status can be overridden by entering a

'service code' (or simply by pressing the 'start' button again). For some printers, special circuit "flashers" are

available that reset the quantity of remaining ink to the maximum. Some manufacturers, most

notably Epson and Hewlett Packard, have been accused of indicating that a cartridge is depleted while a

substantial amount of ink remains.[16][17] A 2007 study found that most printers waste a significant quantity of ink

when they declare a cartridge to be empty. Single-ink cartridges were found to have on average 20% of their ink

remaining, though actual figures range from 9% to 64% of the cartridge's total ink capacity, depending on the

brand and model of printer.[18][19] This problem is further compounded with the use of multi-ink cartridges, which are

declared empty as soon as one color runs low. Of great annoyance to many users are those printers that will not

print documents requiring only black ink when one or more of the color ink cartridges is depleted.

In recent years, many consumers have begun to challenge the business practices of printer manufacturers, such

as charging up to $8000 per gallon for printer ink.[20] Alternatives for consumers are cheaper copies of cartridges,

produced by third parties, and refilling cartridges, using refill kits. Due to the large differences in price caused by

OEM markups, there are many companies specializing in alternative ink cartridges. Most printer manufacturers

discourage refilling disposable cartridges or using aftermarket copy cartridges because of the loss in revenue.

Using incorrect inks may also cause poor image quality due to differences in viscosity, which can affect the amount

of ink ejected in a drop, and color consistency, and can even cause damage to the printhead. Nonetheless, the use

of alternative cartridges and inks has been gaining in popularity, threatening the business model of printer

manufacturers. Printer companies such as HP, Lexmark, and Epson have used patents and the DMCA to launch

lawsuits against 3rd-party vendors.[21][22] An anti-trust class-action lawsuit was even launched against HP and office

supply chain, Staples, alleging that HP paid Staples $100 million to keep inexpensive 3rd-party ink cartridges off

the shelves.[23][24]

This article's factual accuracy may be compromised because of out-of-date information. Please help improve the article by updating it. There may be additional information on the talk page. (February 2010)

In Lexmark Int'l v. Static Control Components, Case No. 03-5400 (6th Cir. Oct. 26, 2004) (Sutton, J.) the United

States Court of Appeals for the Sixth Circuit ruled that circumvention of this technique[clarification needed] does not violate

the Digital Millennium Copyright Act. TheEuropean Commission[citation needed] also ruled this practice anticompetitive: it

will disappear in newer models sold in the European Union.[25] While the DMCA case dealt with copyright

protection, companies also rely on patent protection to prevent copying and refilling of cartridges. For example, if a

company devises all of the ways in which their microchips can be manipulated and cartridges can be refilled and

patents these methods, they can prevent anyone else from refilling their cartridges. Patents protecting the structure

of their cartridges prevent the sale of cheaper copies of the cartridges. For some printer models (notably those

from Canon) the manufacturers own microchip can be removed and fitted to a compatible cartridge thereby

avoiding the need to replicate the microchip (and risk prosecution). Other manufacturers embed their microchips

deep within the cartridge in an effort to prevent this approach.

In 2007 Eastman Kodak entered the inkjet market with its own line of All-In-One printers based on a marketing

model that differed from the prevailing practice of selling the printer at a loss while making large profits on

replacement ink cartridges. Kodak claimed that consumers could save up to 50 percent on printing by using its

lower cost cartridges filled with the company’s proprietary pigmented colorants while avoiding the potential

problems associated with off-brand inks.[2]

[edit]Professional inkjet printers

Besides the well known small inkjet printers for home and office, there is a market for professional inkjet printers,

some being for "page-width" format printing, but most being for wide format printing. Page-width format means that

the print width ranges from about 8.5" to 37" (about 20 cm to 100 cm). "Wide format" means that these are printers

ranging in print width from 24" up to 15' (about 75 cm to 5 m). The application of the page-width printers is for

printing high-volume business communications that have a lesser need for flashy layout and color. Particularly with

the addition of variable data technologies, the page-width printers are important in billing, tagging, and

individualized catalogs and newspapers. The application of most of the wide format printers is for printing

advertising graphics; a minor application is printing of designs by architects or engineers.

Another specialty application for inkjets is producing prepress color proofs for printing jobs created digitally. Such

printers are designed to give accurate color rendition of how the final image will look (a "proof") when the job is

finally produced on a large volume press such as a four-colour offset lithography press. A well-known example of

an inkjet designed for proof work is an Iris printer, and outputs from them are commonly "iris proofs" or just "irises".

In terms of units, the major supplier is Hewlett-Packard, which supply over 90 percent of the market for printers for

printing technical drawings. The major products in their Designjet series are the Designjet 500/800, the Designjet T

Printer series (including the T1100 & T610), the Designjet 1050 and the Designjet 4000/4500. They also have

the HP Designjet 5500, a six-color printer that is used especially for printing graphics as well as the new Designjet

Z6100 which sits at the top of the HP Designjet range and features an eight colour pigment ink system .

A few other suppliers of low volume wide format printers are Epson, Kodak and Canon. Epson has a group of 3

Japanese companies around it that predominantly use Epson piezo printheads and inks: Mimaki, Roland,

and Mutoh.

Scitex Digital Printing developed high-speed, variable-data, inkjet printers for production printing, but sold its

profitable assets associated with the technology to Kodak in 2005 who now market the printers as Kodak

Versamark(tm) VJ1000, VT3000, and VX5000 printing systems. These roll-fed printers can print at up to 1000 feet

per minute.

More professional high-volume inkjet printers are made by a range of companies. These printers can range in price

from $35000 to as high as $2 million. Carriage widths on these units can range from 54" to 192" (about 1.4 to 5 m)

and ink technologies tend toward solvent, eco-solvent and UV-curing as opposed to water-based (aqueous) ink

sets. Major applications where these printers are used are for outdoor settings for billboards, truck sides and truck

curtains, building graphics and banners, while indoor displays include point-of-sales displays, backlit displays,

exhibition graphics and museum graphics.

The major suppliers for professional wide- and grand-format printers include: Agfa Graphics, LexJet, Grapo, Inca,

Durst, Océ, NUR (now part of Hewlett-Packard), Lüscher, VUTEk, Zünd, Scitex Vision (now part of Hewlett-

Packard), Mutoh, Mimaki, Roland DG], Seiko I Infotech, Leggett and Platt, Agfa, Raster Printers, DGI and

MacDermid ColorSpan (now part of Hewlett-Packard)

[edit]Inkjet printing of functional materials

Three-dimensional printing  constructs a prototype by printing cross-sections on top of one another.

U.S.  Patent 6,319,530 describes a "Method of photocopying an image onto an edible web for decorating

iced baked goods". In other words, this invention enables one to inkjet print a food-grade color photograph on

a birthday cake's surface. Many bakeries now carry these types of decorations, which are printable using

edible inks and dedicated inkjet printers[citation needed]. Edible ink printing can be done using normal home use

inkjet printers like Canon Bubble Jet printers with edible ink cartridges installed, and using rice paper or

frosting sheets.

Inkjet printers and similar technologies are used in the production of many microscopic items.

See Microelectromechanical systems.

Inkjet printers are used to form conductive traces for circuits, and color filters in LCD and plasma

displays.

Inkjet printers, especially produced by Dimatix (now part of Fujifilm), Xennia Technology and Pixdro, are

in fairly common use in many labs around the world for developing alternative deposition methods that

conserve material use. These printers have been used in the printing of polymer, macromolecular, quantum

dot, metallic nanoparticles, carbon nanotubes etc. The applications of such printing methods include organic

thin-film transistors, organic light emitting diodes, organic solar cells, sensors, etc.[26]

Inkjet technology is used in the emerging field of bioprinting.

LASER PRINTERA laser printer is a common type of computer printer that rapidly produces high quality text and graphics on plain paper. As with digital photocopiers and multifunction printers (MFPs), laser printers employ a xerographic printing process but differ from analog photocopiers in that the image is produced by the direct scanning of a laser beam across the printer's photoreceptor.

A laser beam projects an image of the page to be printed onto an electrically charged rotating drum coated

with selenium or, more common in modern printers, organic photoconductors. Photoconductivity removes charge

from the areas exposed to light. Dry ink (toner) particles are then electrostatically picked up by the drum's charged

areas. The drum then prints the image onto paper by direct contact and heat, which fuses the ink to the paper.

Unlike impact printers, laser printer speed can vary widely, and depends on many factors, including the graphic

intensity of the job being processed. The fastest models can print over 200 monochrome pages per minute (12,000

pages per hour). The fastest colour laser printers can print over 100 pages per minute (6000 pages per hour). Very

high-speed laser printers are used for mass mailings of personalized documents, such as credit card or utility bills,

and are competing with lithography in some commercial applications. .[1]

The cost of this technology depends on a combination of factors, including the cost of paper, toner, and infrequent

drum replacement, as well as the replacement of other consumables such as the fuser assembly and transfer

assembly. Often printers with soft plastic drums can have a very high cost of ownership that does not become

apparent until the drum requires replacement.

A duplexing printer (one that prints on both sides of the paper) can halve paper costs and reduce filing volumes.

Formerly only available on high-end printers, duplexers are now common on mid-range office printers, though not

all printers can accommodate a duplexing unit. Duplexing can also give a slower page-printing speed, because of

the longer paper path.

In comparison with the laser printer, most inkjet printers and dot-matrix printers simply take an incoming stream of

data and directly imprint it in a slow lurching process that may include pauses as the printer waits for more data. A

laser printer is unable to work this way because such a large amount of data needs to output to the printing device

in a rapid, continuous process. The printer cannot stop the mechanism precisely enough to wait until more data

arrives, without creating a visible gap or misalignment of the dots on the printed page.

[edit]History

Gary Starkweather in 2009.

The laser printer was invented at Xerox in 1969 by researcher Gary Starkweather, who had an improved printer

working by 1971[2] and incorporated into a fully functional networked printer system by about a year later.[3] The

prototype was built by modifying an existing xerographic copier. Starkweather disabled the imaging system and

created a spinning drum with 8 mirrored sides, with a laser focused on the drum. Light from the laser would bounce

off the spinning drum, sweeping across the page as it traveled through the copier. The hardware was completed in

just a week or two, but the computer interface and software took almost 3 months to complete.[citation needed]

The first commercial implementation of a laser printer was the IBM model 3800 in 1975, used for high-volume

printing of documents such as invoices and mailing labels. It is often cited as "taking up a whole room," implying

that it was a primitive version of the later familiar device used with a personal computer. While large, it was

designed for an entirely different purpose. Many 3800s are still in use.[citation needed]

The first laser printer designed for use in an office setting was released with the Xerox Star 8010 in 1981. Although

it was innovative, the Star was an expensive ($17,000) system that was purchased by only a relatively small

number of businesses and institutions. After personal computers became more widespread, the first laser printer

intended for a mass market was the HP LaserJet 8ppm, released in 1984, using aCanon engine controlled by HP

software. The HP LaserJet printer was quickly followed by laser printers from Brother Industries, IBM, and others.

First-generation machines had large photosensitive drums, of circumference greater than the paper length. Once

faster-recovery coatings were developed, the drums could touch the paper multiple times in a pass, and could

therefore be smaller in diameter.

Laser printers brought fast, high quality text printing with multiple fonts on a page to the business and consumer

markets. No other commonly available printer could offer this combination of features.

As with most electronic devices, the cost of laser printers has fallen markedly over the years. In 1984, the HP

LaserJet sold for $3500,[4] had trouble with even small, low resolution graphics, and weighed 71 pounds (32 kg).

Low end monochrome laser printers often sell for less than $75 as of 2008. These printers tend to lack onboard

processing and rely on the host computer to generate a raster image (see Winprinter), but still will outperform the

LaserJet Classic in nearly all situations.

[edit]How it works

Main article: Xerography

There are typically seven steps involved in the laser printing process:

[edit]Raster image processing

Each horizontal strip of dots across the page is known as a raster line or scan line. Creating the image to be

printed is done by a Raster Image Processor (RIP), typically built into the laser printer. The source material may be

encoded in any number of special page description languages such as Adobe PostScript (PS), HP Printer

Command Language (PCL), or Microsoft XML Page Specification (XPS), as well as unformatted text-only data.

The RIP uses the page description language to generate a bitmap of the final page in the raster memory.

For fully graphical output using a page description language, a minimum of 1 megabyte of memory is needed to

store an entire monochrome letter/A4 sized page of dots at 300 dpi. At 300 dpi, there are 90,000 dots per square

inch (300 dots per linear inch). A typical 8.5 x 11 sheet of paper has 0.25-inch (6.4 mm) margins, reducing the

printable area to 8.0 x 10.5 inches (270 mm), or 84 square inches. 84 sq/in x 90,000 dots per sq/in = 7,560,000

dots. Meanwhile 1 megabyte = 1,048,576 bytes, or 8,388,608 bits, which is just large enough to hold the entire

page at 300 dpi, leaving about 100 kilobytes to spare for use by the raster image processor.

In a color printer, each of the four CYMK toner layers is stored as a separate bitmap, and all four layers are

typically preprocessed before printing begins, so a minimum of 4 megabytes is needed for a full-color letter-size

page at 300 dpi.

Memory requirements increase with the square of the dpi, so 600 dpi requires a minimum of 4 megabytes for

monochrome, and 16 megabytes for colour at 600 dpi. Printers capable of tabloid and larger size may include

memory expansion slots.

[edit]Charging

Applying a negative charge to the photosensitive drum

In older printers, a corona wire positioned parallel to the drum, or in more recent printers, a primary charge roller,

projects an electrostatic charge onto the photoreceptor (otherwise named the photoconductor unit), a revolving

photosensitive drum or belt, which is capable of holding an electrostatic charge on its surface while it is in the dark.

An AC bias is applied to the primary charge roller to remove any residual charges left by previous images. The

roller will also apply a DC bias on the drum surface to ensure a uniform negative potential.

Numerous patents[specify] describe the photosensitive drum coating as a siliconsandwich with a photocharging layer,

a charge leakage barrier layer, as well as a surface layer. One version[specify] uses amorphous silicon containing

hydrogen as the light receiving layer, Boron nitride as a charge leakage barrier layer, as well as a surface layer

of doped silicon, notably silicon with oxygen or nitrogen which at sufficient concentration resembles

machining silicon nitride

[edit]Exposing

Laser neutralizing the negative charge on the photoreceptive drum to form the static electric image.

The laser is aimed at a rotating polygonal mirror, which directs the laser beam through a system of lenses and

mirrors onto the photoreceptor. The cylinder continues to rotate during the sweep and the angle of sweep

compensates for this motion. The stream of rasterized data held in memory turns the laser on and off to form the

dots on the cylinder. Lasers are used because they generate a narrow beam over great distances. The laser beam

neutralizes (or reverses) the charge on the black parts of the image, leaving a static electric negative image on the

photoreceptor surface to lift the toner particles.

Some non-laser printers expose by an array of light emitting diodes spanning the width of the page, rather than by

a laser.

[edit]Developing

The surface with the latent image is exposed to toner, fine particles of dry plastic powder mixed with carbon black

or colouring agents. The charged toner particles are given a negative charge, and are electrostatically attracted to

the photoreceptor's latent image, the areas touched by the laser. Because like charges repel, the negatively

charged toner will not touch the drum where the negative charge remains.

[edit]Transferring

The photoreceptor is pressed or rolled over paper, transferring the image. Higher-end machines use a positively

charged transfer roller on the back side of the paper to pull the toner from the photoreceptor to the paper.

[edit]Fusing

Melting toner onto paper using heat and pressure.

The paper passes through rollers in the fuser assembly where heat (up to 200 Celsius) and pressure bond the

plastic powder to the paper.

One roller is usually a hollow tube (heat roller) and the other is a rubber backing roller (pressure roller). A radiant

heat lamp is suspended in the center of the hollow tube, and its infrared energy uniformly heats the roller from the

inside. For proper bonding of the toner, the fuser roller must be uniformly hot.

Some printers use a very thin flexible metal fuser roller, so there is less mass to be heated and the fuser can more

quickly reach operating temperature. If paper moves through the fuser more slowly, there is more roller contact

time for the toner to melt, and the fuser can operate at a lower temperature. Smaller, inexpensive laser printers

typically print slowly, due to this energy-saving design, compared to large high speed printers where paper moves

more rapidly through a high-temperature fuser with a very short contact time

[edit]Cleaning

Magnification of color laser printer output, showing individual toner particles comprising 4 dots of an image with a bluish

background

When the print is complete, an electrically neutral soft plastic blade cleans any excess toner from the

photoreceptor and deposits it into a waste reservoir, and a discharge lamp removes the remaining charge from the

photoreceptor.

Toner may occasionally be left on the photoreceptor when unexpected events such as a paper jam occur. The

toner is on the photoconductor ready to apply, but the operation failed before it could be applied. The toner must

be wiped off and the process restarted.

[edit]Multiple steps occurring at once

Once the raster image generation is complete all steps of the printing process can occur one after the other in

rapid succession. This permits the use of a very small and compact unit, where the photoreceptor is charged,

rotates a few degrees and is scanned, rotates a few more degrees and is developed, and so forth. The entire

process can be completed before the drum completes one revolution.

Different printers implement these steps in distinct ways. Some "laser" printers actually use a linear array of light-

emitting diodes to "write" the light on the drum (see LED printer). The toner is based on either wax or plastic, so

that when the paper passes through the fuser assembly, the particles of toner melt. The paper may or may not be

oppositely charged. The fuser can be an infrared oven, a heated pressure roller, or (on some very fast, expensive

printers) a xenon flash lamp. The Warm Up process that a laser printer goes through when power is initially applied

to the printer consists mainly of heating the fuser element.

[edit]Color laser printers

Fuji Xerox color laser printer C1110B

Color laser printers use colored toner (dry ink), typically cyan, magenta, yellow, and black(CMYK).

While monochrome printers only use one laser scanner assembly, color printers often have two or more scanner

assemblies.

Color printing adds complexity to the printing process because very slight misalignments known as registration

errors can occur between printing each color, causing unintended color fringing, blurring, or light/dark streaking

along the edges of colored regions. To permit a high registration accuracy, some color laser printers use a large

rotating belt called a "transfer belt". The transfer belt passes in front of all the toner cartridges and each of the

toner layers are precisely applied to the belt. The combined layers are then applied to the paper in a uniform single

step.

Color printers usually have a higher cost per page production cost than monochrome printers.

[edit]DPI Resolution

1200 DPI printers are commonly available during 2008.

2400 DPI electrophotographic printing plate makers, essentially laser printers that print on plastic sheets,

are also available.

[edit]Laser printer maintenance

Most consumer and small business laser printers use a toner cartridge that combines the photoreceptor

(sometimes called "photo conductor unit" or "imaging drum") with the toner supply bin, the waste toner hopper, and

various wiper blades. When the toner supply is consumed, replacing the toner cartridge automatically replaces the

imaging drum, waste toner hopper, and wiper blades.

Some laser printers maintain a page count of the number of pages printed since last maintenance. On these

models, a reminder message will appear informing the user it is nearing time to replace standard maintenance

parts. On other models, no page count is kept or no reminder is displayed, so the user must keep track of pages

printed manually or watch for warning signs like paper feed problems and print defects.

Manufacturers usually provide life expectancy charts for common printer parts and consumables. Manufacturers

rate life expectancy for their printer parts in terms of "expected page-production life" rather than in units of time.

Consumables and maintenance parts for Business-class printers will generally be rated for a higher page-

production expectancy than parts for personal printers. In particular, toner cartridges and fusers usually have a

higher page production expectancy in business-class printers than personal-class printers. Colour laser printers

can require more maintenance and parts replacement than monochrome laser printers since they contain more

imaging components.

For rollers and assemblies involved in the paper pickup path and paper feed path, typical maintenance is to

vacuum toner and dust from the mechanisms, and replace, clean, or restore the rubber paper-handling rollers.

Most pickup, feed, and separation rollers have a rubber coating which eventually suffers wear and becomes

covered with slippery paper dust. In cases where replacement rollers are discontinued or unavailable, rubber

rollers can be cleaned safely with a damp lint-free rag. Commercial chemical solutions are also available which

may help temporarily restore the traction of the rubber.

The fusing assembly (also called a "fuser") is generally considered a replaceable consumable part on laser

printers. The fusing assembly is responsible for melting and bonding the toner to the paper. There are many

possible defects for fusing assemblies: defects include worn plastic drive gears, electronic failure of heating

components, torn fixing film sleeves, worn pressure rollers, toner buildup on heating rollers and pressure rollers,

worn or scratched pressure rollers, and damaged paper sensors.

Some manufacturers offer preventative maintenance kits specific to each printer model; such kits generally include

a fuser and may also include pickup rollers, feed rollers, transfer rollers, charge rollers, and separation pads.

[edit]Plane ban

After the October 2010 cargo planes bomb plot, in which cargo containing laser printers with toner cartridges filled

with explosives were discovered on separate cargo planes, the U.S. prohibited passengers from carrying certain

printer cartridges on flights.[5] The U.S.Transportation Security Administration said it would ban toner and ink

cartridges weighing over 16 ounces (453 grams) from all passenger flights.[6][7] U.S. Homeland Security

Secretary Janet Napolitano said the ban would apply to both carry-on bags and checked bags on domestic and

international flights in-bound to the U.S.[7] PC Magazine opined that the ban would not affect average travelers,

whose toner cartridges are generally lighter, but would affect the importing of laser printer supplies, as many laser

toner cartridges weigh well in excess of a pound.[7]

[edit]Steganographic anti-counterfeiting ("secret") marks

Illustration of small yellow dots on white paper, generated by a colour laser printer

Main article: Printer steganography

Many modern colour laser printers mark printouts by a nearly invisible dot raster, for the purpose of identification.

The dots are yellow and about 0.1 mm in size, with a raster of about 1 mm. This is purportedly the result of a deal

between the U.S. government and printer manufacturers to help track counterfeiters.[8]

The dots encode data such as printing date, time, and printer serial number in binary-coded decimal on every

sheet of paper printed, which allows pieces of paper to be traced by the manufacturer to identify the place of

purchase, and sometimes the buyer.

Digital rights advocacy groups such as the Electronic Frontier Foundation are concerned about this erosion of the

privacy and anonymity of those who print.[9]

[edit]Safety hazards, health risks, and precautions

[edit]Shock hazards

Although modern printers include many safety interlocks and protection circuits, it is possible for a high voltage or a

residual voltage to be present on the various rollers, wires, and metal contacts inside a laser printer. Care should

be taken to avoid unnecessary contact with these parts to reduce the potential for painful electrical shock.

[edit]Toner clean-up

Toner particles are designed to have electrostatic properties and can develop static-electric charges when they rub

against other particles, objects, or the interiors of transport systems and vacuum hoses. Because of this and its

small particle size, toner should not be vacuumed with a conventional home vacuum cleaner. Static discharge from

charged toner particles can ignite dust in the vacuum cleaner bag or create a small explosion if sufficient toner is

airborne. This may damage the vacuum cleaner or start a fire. In addition, toner particles are so fine that they are

poorly filtered by conventional household vacuum cleaner filter bags and blow through the motor or back into the

room.

Toner particles melt (or fuse) when warmed. Small toner spills can be wiped up with a cold, damp cloth.

If toner spills into the laser printer, a special type of vacuum cleaner with an electrically conductive hose and a high

efficiency (HEPA) filter may be needed for effective cleaning. These are called ESD-safe (Electrostatic Discharge-

safe) or toner vacuums. Similar HEPA-filter equipped vacuums should be used for clean-up of larger toner spills.

Toner is easily cleaned from most water-washable clothing. As toner is a wax or plastic powder with a low melting

temperature, it must be kept cold during the cleaning process. Washing a toner stained garment in cold water is

often successful. Even warm water is likely to result in permanent staining. The washing machine should be filled

with cold water before adding the garment. Washing through two cycles improves the chances of success. The first

may use hand wash dish detergent, with the second cycle using regular laundry detergent. Residual toner floating

in the rinse water of the first cycle will remain in the garment and may cause a permanent graying. A clothes dryer

or iron should not be used until it is certain that all the toner has been removed.

[edit]Ozone hazards

As a natural part of the printing process, the high voltages inside the printer can produce a corona discharge that

generates a small amount of ionized oxygen and nitrogen, forming ozone and nitrogen oxides. In larger

commercial printers and copiers, a carbon filter in the air exhaust stream breaks down these oxides to prevent

pollution of the office environment.

However, some ozone escapes the filtering process in commercial printers, and ozone filters are not used in many

smaller consumer printers. When a laser printer or copier is operated for a long period of time in a small, poorly

ventilated space, these gases can build up to levels at which the odor of ozone or irritation may be noticed. A

potential for creating a health hazard is theoretically possible in extreme cases. [10]

[edit]Respiratory health risks

According to a recent study conducted in Queensland, Australia, some printers emit sub-micrometre particles

which some suspect may be associated with respiratory diseases.[11] Of 63 printers evaluated in the Queensland

University of Technology study, 17 of the strongest emitters were made by Hewlett-Packard and one by Toshiba.

The machine population studied, however, was only those machines already in place in the building and was thus

biased toward specific manufacturers. The authors noted that particle emissions varied substantially even among

the same model of machine. According to Professor Morawska of Queensland University, one printer emitted as

many particles as a burning cigarette.[12]

"The health effects from inhaling ultrafine particles depend on particle composition, but the results can

range from respiratory irritation to more severe illness such as cardiovascular problems or cancer."

(Queensland University of Technology).[13]

A 2006 study in Japan found that laser printers increase concentrations of styrene, xylenes, and ozone, and

that ink-jet printers emittedpentanol.[14]

Muhle et al. (1991) reported that the responses to chronically inhaled copying toner, a plastic dust

pigmented with carbon black, titanium dioxide and silica were also similar qualitatively to titanium dioxide

and diesel exhaust.[15]

Daisy wheel printerFrom Wikipedia, the free encyclopedia

This article is missing citations or needs footnotes. Please help add inline citations to guard against copyright violations and factual inaccuracies. (December 2007)

Metal Daisy Wheel for Xerox & Diablo printers

Plastic Daisy Wheel for Qume printers

Samples of daisy-wheel printer output. Actual print is much crisper than these images.

Daisy wheel printers use an impact printing technology invented in 1969 by David S. Lee atDiablo Data Systems.

It uses interchangeable pre-formed type elements, each with typically 96glyphs, to generate high-quality output

comparable to premium typewriters such as the IBM "Golfball" Selectric, but three times faster. Daisy-wheel

printing was used in electronic typewriters,word processors and computer systems from 1972.

By 1980 daisy-wheel printers had become the dominant technology for high-quality print. Dot-matrix

impact or thermal printers were used where higher speed was required and poor print quality was acceptable. Both

technologies were rapidly superseded for most purposes when dot-based printers—in particular laser printers—that could print any characters or graphics rather than being restricted to a limited character set became able to produce output of comparable quality. Daisy-wheel technology is now found only in some electronic typewriters.

Contents

 [hide]

1   Description

o 1.1   Thimble printers

2   History

3   Graphics

4   See also

5   Notes

[edit]Description

The heart of the system is an interchangeable metal or plastic "daisy wheel" holding an entire character set as

raised characters moulded on each "petal". In use a servo motor rotates the daisy wheel to position the required

character between the hammer and the ribbon. The solenoid-operated hammer then fires, driving the character

type on to the ribbon and paper to print the character on the paper. The daisy wheel and hammer are mounted on

a sliding carriage similar to that used by dot matrix printers.

Different typefaces and sizes can be used by replacing the daisy wheel. It is possible to use multiple fonts within a

document: font changing is facilitated by printer driver software which can position the carriage to the center of the

platen and prompt the user to change the wheel before continuing printing. However, printing a document with

frequent font changes and thus required frequent wheel changes was still an arduous task.

Many daisy wheel machines offer a bold type facility, accomplished by double- or triple-striking the specified

character(s); servo-based printers advance the carriage fractionally for a wider (and therefore blacker) character,

while cheaper machines perform a carriage return without a line feed to return to the beginning of the line, space

through all non-bold text, and restrike each bolded character. The inherent imprecision in attempting to restrike on

exactly the same spot after a carriage return provides the same effect as the more expensive servo-based printers,

with the unique side effect that as the printer ages and wears, bold text becomes bolder.

Like all other impact printers, daisy wheel printers are noisy.

[edit]Thimble printers

Thimble printers were closely related to daisy wheel printers, but instead of a flat wheel the petals were bent to

form a cup-shaped "thimble" print element. Introduced by NEC in 1977 as their "Spinwriter" series, the replaceable

thimbles each held 128 characters.[1][2]

[edit]History

In 1972 a team at Diablo Systems led by engineer David S. Lee developed the first commercially successful daisy-

wheel printer, a device that was faster and more flexible than IBM's golf-ball devices, being capable of 30 cps

(characters per second), whereas IBM's Selectric operated at 13.4 cps.[3]

Xerox acquired Diablo that same year, following which Lee departed to set up Qume Corporation in 1973. Xerox's

Office Product Division had already been buying Diablo printers for its Redactron text editors. After 7 years trying

to make Diablo profitable, the OPD focused on developing and selling the Diablo 630 which was mostly bought by

companies such as Digital Equipment Corporation.[citation needed] The Diablo 630 could produce letter quality output as

good as that produced by an IBM Selectric or Selectric-based printer, but at a lower cost. A further advantage was

that it supported the entire ASCII printing character set. Its servo-controlled carriage also permitted the use

ofproportional spaced fonts, where characters occupy a different amount of horizontal space according to their

width.

The Diablo 630 was so successful that virtually all later daisy wheel printers, as well as many dot matrix printers

and even the original Apple Laserwriter either copied its command set or could emulate one. Daisy wheel printers

from Diablo and Lee's 1973 company Qume were the dominant high-end output technology for computer and

office automation applications by 1980, though high speed non-impact techniques were already entering the

market (e.g. IBM 6640 inkjet, Xerox 2700 and IBM 6670 laser). From 1981 onwards the IBM PC's introduction of

"Code page 437" with 254 printable glyphs (including 40 shapes specifically for drawing forms), and development

of Xerox Star-influenced environments such as the Macintosh, GEM and Windows made bit-mapped approaches

more desirable, driving cost reductions for laser printing and higher resolution for impact dot matrix printing.

Xerox later adapted Diablo's daisy wheel technology into a typewriter that sold for less than $50. An automated

factory was built near Dallasthat took less than 30 minutes to assemble a Xerox typewriter. The Xerox typewriter

was well received but never achieved the projected sales numbers due to the advent of the PC and word

processing software. The typewriter was later modified to be compatible with PCs but the engineering which made

it a low cost device reduced its flexibility.[4] By the mid-1980s daisy wheel technology was rapidly becoming

obsolete due to the growing spread of affordable laser and inkjet machines, and daisy wheel machines soon

disappeared except for the small remaining typewriter market.

[edit]Graphics

Although the daisy wheel principle is basically inappropriate for printing bitmap graphics, there were attempts to

enable them to do so. Most daisy wheel printers supported a relatively coarse and extremely slow graphics mode

by printing the image entirely out of full stops (also called periods). This required a mechanism capable of pixel by

pixel movement, both horizontally and vertically, and low-end printers were incapable of it. [5] Given the slow speed

and the coarse resolution this was not a feasible technique for printing large images, but could usefully print a

small logo onto a letterhead and then the following letter, all in a single unattended print run without changing the

print element.

Consideration was also given to optimising graphic printing by changing the glyphs on the daisy wheel to a set that

would be able to print all the required bitmap combinations more quickly, without requiring an impact for every

single dot. This would have the advantage that vertical dot combinations could be printed in a single impact,

without requiring fine rotation control of the platen roller. However it would require a specialised daisy wheel so

printing of a letter and letterhead would require a two-step process with a manual wheel change in-between.[6] As

the development of this technique post-dated the widespread availability of 24-pin dot matrix printers and coincided

with the arrival of affordable laser printers in offices, it was never a popular approach.

LED printerFrom Wikipedia, the free encyclopedia

Kodak LED printer

Oki LED printhead

An LED printer is a type of laser computer printer. LED technology uses a light-emitting diodearray as a light

source in the printhead. The LED bar pulse-flashes across the entire page width and creates the image on the print

drum or belt as it moves past.

LEDs are more efficient and reliable than conventional laser printers, since they have fewer moving parts.

Depending on design, LED printers can have faster rates of print than some laser-based designs, and are

generally cheaper to manufacture. Laser systems rely on elaborate combinations of rotating mirrors and lenses

that must remain in alignment throughout their use. The laser scans from one end of a line to another, then starts

on the next line. Unlike laser printers, an LED printhead has no moving parts.

LED printing was invented by Casio.[1]

[edit]Resolution

How non-uniform LED printer resolutions work.

LED printers have a technical limitation that prevents ready competition with the highest quality laser printers: only

so many LEDs can be packed into a linear physical space. A printer having 300 dots-per-inch resolution must have

300 LEDs per inch, and a printer with 600 dpi resolution must have 600 LEDs per inch.

Many laser printers now commonly print at 1200 dpi, but making LEDs that small is difficult. It is not uncommon to

see LED printers that use a skewed image resolution such as 600x1200 dpi[2]. The horizontal resolution is limited to

600 dpi[citation needed] by the physical size of the LEDs, but the vertical resolution is simply a matter of how fast the

LEDs flash as the paper passes by. Image quality depends on the spot shape of each LED. A round pixel/spot will

mean that pixels overlap in the vertical direction, while a squashed-oval pixel/spot allows the spots to not overlap

and permit a slightly better image quality.

Dot matrix printerFrom Wikipedia, the free encyclopedia

Epson VP-500 Printer (Cover removed)

Typical output from a dot matrix printer operating in draftmode. This entire image represents an area of printer output approximately 4.5 cm × 1.5cm (1.75 × 0.6 inches) in size.

Part of the series on theHistory of printing

Woodblock printing 200

Movable type 1040

Printing press 1454

Lithography 1796

Laser printing 1969

Thermal printing circa 1972

A dot matrix printer or impact matrix printer is a type of computer printer with a print head that runs back and

forth, or in an up and down motion, on the page and prints by impact, striking an ink-soaked cloth ribbon against

the paper, much like the print mechanism on a typewriter. However, unlike a typewriter or daisy wheel printer,

letters are drawn out of a dot matrix, and thus, varied fonts and arbitrary graphics can be produced. Because the

printing involves mechanical pressure, these printers can createcarbon copies and carbonless copies.

Each dot is produced by a tiny metal rod, also called a "wire" or "pin", which is driven forward by the power of a

tiny electromagnet or solenoid, either directly or through small levers (pawls). Facing the ribbon and the paper is a

small guide plate (often made of an artificial jewel such as sapphire or ruby [1] ) pierced with holes to serve as guides

for the pins. The moving portion of the printer is called the print head, and when running the printer as a generic

text device generally prints one line of text at a time. Most dot matrix printers have a single vertical line of dot-

making equipment on their print heads; others have a few interleaved rows in order to improve dot density.

These machines can be highly durable. When they do wear out, it is generally due to ink invading the guide plate

of the print head, causing grit to adhere to it; this grit slowly causes the channels in the guide plate to wear from

circles into ovals or slots, providing less and less accurate guidance to the printing wires. Eventually, even

with tungsten blocks and titanium pawls, the printing becomes too unclear to read.

Although nearly all inkjet, thermal, and laser printers print closely-spaced dots rather than continuous lines or characters, it is not customary to call them dot matrix printers.

Contents

 [hide]

1   Early Dot Matrix Printers

2   Dot matrix usage

o 2.1   Personal Computers

o 2.2   Pseudo-Color

o 2.3   Near Letter Quality (NLQ)

o 2.4   24-pin printers

o 2.5   Use of dot matrix printers today

3   Advantages and disadvantages

o 3.1   Advantages

o 3.2   Disadvantages

4   Future of dot-matrix printers

5   See also

6   References

7   External links

[edit]Early Dot Matrix Printers

Upper image: Inmac ink ribbon cartridge with black ink for Dot matrix printer

Lower image: Inked and folded lengthy ribbon squeeze in the cartridge, zoom in of inside part, pull ribbon in mechanism and

ribbon.

The LA30 was a 30 character/second dot matrix printer introduced in 1970 by Digital Equipment

Corporation of Maynard, Massachusetts. It printed 80 columns of uppercase-only 5x7 dot matrix characters across

a unique-sized paper. The printhead was driven by astepper motor and the paper was advanced by a somewhat-

unreliable and definitely noisysolenoid ratchet drive. The LA30 was available with both a parallel interface and a

serial interface; however, the serial LA30 required the use of fill characters during the carriage-return operation.

The LA30 was followed in 1974 by the LA36, which achieved far greater commercial success, becoming for a time

the standard dot matrix computer terminal. The LA36 used the same print head as the LA30 but could print on

forms of any width up to 132 columns of mixed-case output on standard green bar fanfold paper. The carriage was

moved by a much-more-capable servo drive using a dc motor and an optical encoder/tachometer. The paper was

moved by a stepper motor. The LA36 was only available with a serial interface but unlike the earlier LA30, no fill

characters were required. This was possible because, while the printer never communicated at faster than 30

characters per second, the mechanism was actually capable of printing at 60 characters per second. During the

carriage return period, characters were buffered for subsequent printing at full speed during a catch-up period. The

two-tone buzz produced by 60 character-per-second catch-up printing followed by 30 character-per-second

ordinary printing was a distinctive feature of the LA36.

Digital then broadened the basic LA36 line onto a wide variety of dot matrix printers including:

LA180 -- 180 c/s line printer

LS120 -- 120 c/s terminal

LA120 -- 180 c/s advanced terminal

LA34 -- Cost-reduced terminal

LA38 -- An LA34 with more features

LA12 -- A portable terminal

In 1970, Centronics (then of Hudson, New Hampshire) introduced a dot matrix printer, the Centronics 101. The

search for a reliable printer mechanism led it to develop a relationship with Brother Industries, Ltd. of Japan, and

the sale of Centronics-badged Brother printer mechanisms equipped with a Centronics print head and Centronics

electronics. Unlike Digital, Centronics concentrated on the low-end line printer marketplace with their distinctive

units. In the process, they designed the parallel electrical interface that was to become standard on most dot

matrix printers (indeed, most printers in general) until it started to be replaced by the Universal Serial Bus (USB) in

the late 1990s.

[edit]Dot matrix usage

[edit]Personal Computers

An Epson MX-80

In the 1970s and 1980s, dot matrix impact printers were generally considered the best combination of expense and

versatility, and until the 1990s they were by far the most common form of printer used with personal computers.

The Epson MX-80 was the groundbreaking model that sparked the initial popularity of impact printers in the

personal computer market. The MX-80 combined affordability with solid text output (for its time). Early impact

printers (including the MX) were notoriously loud during operation, a result of the hammer-like mechanism in the

print head. Furthermore, the MX-80's low dot density (60dpi horizontal, 72dpi vertical) produced printouts of a

distinctive "computerized" quality. When compared to the crisp typewriter quality of a daisy-wheel printer, the dot-

matrix printer's legibility appeared especially bad. In office applications, output quality was a serious issue, as the

dot-matrix text's readability would rapidly degrade with each photocopygeneration.

Initially, third-party software (such as the Bradford printer enhancement program) offered a quick fix to the quality

issue. The software utilized a variety of software techniques to increase print quality; general strategies were

doublestrike (print each line twice), and double-density mode (slow the print head to allow denser and more

precise dot placement). Such add-on software was inconvenient to use, because it required the user to remember

to run the enhancement program before each printer session (to activate the enhancement mode). Furthermore,

not all enhancement software was compatible with all programs.

Early personal computer software focused on the processing of text, but as graphics displays became ubiquitous

throughout the personal computer world, users wanted to print both text and images. Ironically, whereas the daisy-

wheel printer and pen-plotter struggled to reproduce bitmap images, the first dot-matrix impact printers (including

the MX-80) lacked the ability to print computer-generated images. Yet the dot-matrix print head was well-suited to

this task, and the capability quickly became a standard feature on all PC-oriented dot-matrix printers.

Progressive hardware improvements to impact printers boosted the carriage speed, added more (typeface) font

options, increased the dot density (from 60dpi up to 240dpi), and added pseudo-color printing. Faster carriage

speeds meant faster (and sometimes louder) printing. Additional typefaces allowed the user to vary the text

appearance of printouts. Proportional-spaced fonts allowed the printer to imitate the non-uniform character widths

of a typesetter. Increased dot density allowed for more detailed, darker printouts. The impact pins of the printhead

were constrained to a minimum size (for structural durability), and dot densities above 100dpi merely caused

adjacent dots to overlap. While the pin diameter placed a lower limit on the smallest reproducible graphic detail,

manufacturers were able to use higher dot density to great effect in improving text quality.

Several dot-matrix impact printers (such as the Epson FX series) offered 'user-downloadable fonts'. This gave the

user the flexibility to print with different typefaces. PC software uploaded a user-defined fontset into the printer's

memory, replacing the built-in typeface with the user's selection. Any subsequent text printout would use the

downloaded font, until the printer was powered off or soft-reset. Several third-party programs were developed to

allow easier management of this capability. With a supported word-processor program (such as WordPerfect5.1),

the user could embed up to 2 NLQ custom typefaces in addition to the printer's built-in (ROM) typefaces. (The later

rise of WYSIWYGsoftware philosophy rendered downloaded fonts obsolete.)

Single-strike and Multi-strike ribbons were an attempt to address issues in the ribbon's ink quality. Standard printer

ribbons used the same principles as typewriter ribbons. The printer would be at its darkest with a newly installed

ribbon cartridge, but would gradually grow fainter with each successive printout. The variation in darkness over the

ribbon cartridge's lifetime prompted the introduction of alternative ribbon formulations. Single-strike ribbons used a

carbon-like substance in typewriter ribbons transfer. As the ribbon was only usable for a single loop (rated in terms

of 'character count'), the blackness was of consistent, outstanding darkness. Multi-strike ribbons gave an increase

in ribbon life, at the expense of quality.

[edit]Pseudo-Color

Several manufacturers implemented color dot-matrix impact printing through a multi-color ribbon. Color was

achieved through a multi-pass composite printing process. During each pass, the print head struck a different

section of the ribbon (one primary color.) For a 4-color ribbon, each printed line of output required a total of 4

passes. In some color printers, such as the Apple ImageWriter II, the printer moved the ribbon relative to the fixed

print head assembly. In other models, the print head was tilted against a stationary ribbon.

Due to their poor color quality and increased operating expense, color impact models never replaced their

monochrome counterparts.[citation needed] As the color ribbon was used in the printer, the black ink section would

gradually contaminate the other 3 colors, changing the consistency of printouts over the life of the ribbon. Hence,

the color dot-matrix was suitable for abstract illustrations and piecharts, but not for photo-realistic reproduction.

Dot-matrix thermal-transfer printers offered more consistent color quality, but consumed printer film, still more

expensive. Color printing in the home would only become ubiquitous much later, with the ink-jet printer.The speed

is usually 30-550 cps

[edit]Near Letter Quality (NLQ)

Text quality was a recurring issue with dot-matrix printers. Near Letter Quality mode endowed dot-matrix printers

with a simulated typewriter-like quality. By using multiple passes of the carriage, and higher dot density, the printer

could increase the effective resolution. For example, the Epson FX-86 could achieve a theoretical addressable dot-

grid of 240 by 216 dots/inch using a print head with a vertical dot density of only 72 dots/inch, by making multiple

passes of the print head for each line. For 240 by 144 dots/inch, the print head would make one pass, printing 240

by 72 dots/inch, then the printer would advance the paper by half of the vertical dot pitch (1/144 inch), then the

print head would make a second pass. For 240 by 216 dots/inch, the print head would make three passes with

smaller paper movement (1/3 vertical dot pitch, or 1/216 inch) between the passes. To cut hardware costs, some

manufacturers merely used a double strike (doubly printing each line) to increase the printed text's boldness,

resulting in bolder but still jagged text. In all cases, NLQ mode incurred a severe speed penalty. Not surprisingly,

all printers retained one or more 'draft' modes for high-speed printing.

NLQ became a standard feature on all dot-matrix printers. While NLQ was well received in the IBM PC market, the

Apple Macintosh market did not use NLQ mode at all, as it did not rely on the printer's own fonts. Mac word-

processing applications used fonts stored in the computer. For non-PostScript (raster) printers, the final raster

image was produced by the computer and sent to the printer, which meant dot-matrix printers on the Mac platform

exclusively used raster ("graphics") printing mode. For near-letter-quality output, the Mac would simply double the

resolution used by the printer, to 144 dpi, and use a screen font twice the point size desired. Since the Mac's

screen resolution (72 dpi) was exactly half of the ImageWriter's maximum, this worked perfectly, creating text at

exactly the desired size.

[edit]24-pin printers

By the mid 1980s, manufacturers had increased the pincount of the impact printhead from 9 pins to 18, or 24. (At

27 pins, the AppleImageWriter LQ held the record for consumer market). The increased pin-count permitted

superior print-quality which was necessary for success in Asian markets to print legible CJK characters. In the PC

market, nearly all 9-pin printers printed at a defacto-standard vertical pitch of 9/72 inch (per printhead pass, ie

8 lpi). Epson's 24-pin LQ-series rose to become the new de-facto standard, at 24/180 inch (per pass - 7.5 lpi). Not

only could a 24-pin printer lay down a denser dot-pattern in a single-pass, it could simultaneously cover a larger

area.

Compared to the older 9-pin models, a new 24-pin impact printer not only produced better-looking NLQ text, it

printed the page quicker (largely due to the 24-pin's ability to print NLQ with a single pass). 24-pin printers

repeated this feat in bitmap graphics mode, producing higher-quality graphics in reduced time. While the text-

quality of a 24-pin was still visibly inferior to a true letter-quality printer—the daisy wheel or laser-printer, the typical

24-pin impact printer outpaced most daisy-wheel models.

As manufacturing costs declined, 24-pin printers gradually replaced 9-pin printers. 24-pin printers reached a dot-

density of 360x360 dpi, a marketing figure aimed at potential buyers of competing ink-jet and laser-printers. 24-pin

NLQ fonts generally used a dot-density of 360x180, the highest allowable with single-pass printing. Multipass NLQ

was abandoned, as most manufacturers felt the marginal quality improvement did not justify the tradeoff in speed.

Most 24-pin printers offered 2 or more NLQ typefaces, but the rise of WYSIWYG software and GUIenvironments

such as Microsoft Windows ended the usefulness of NLQ.

[edit]Use of dot matrix printers today

The desktop impact printer was gradually replaced by the inkjet printer. When Hewlett-Packard's patents expired

on steam-propelled photolithographically-produced ink-jet heads, the inkjet mechanism became available to the

printer industry. The inkjet was superior in nearly all respects: comparatively quiet operation, faster print speed,

and output quality almost as good as a laser printer. By the mid-1990s, inkjet technology had surpassed dot-matrix

in the mainstream market.

As of 2005, dot matrix impact technology remains in use in devices such as cash registers, ATM, and many other

point-of-sales terminals.Thermal printing is gradually supplanting them in these applications. Full-size dot-matrix

impact printers are still used to print multi-part stationery, for example at bank tellers, and other applications where

use of tractor feed paper is desirable such as data logging and aviation. Some are even fitted with USB interfaces

as standard to aid connection to modern legacy-free computers. Dot matrix printers are also more tolerant of the

hot and dirty operating conditions found in many industrial settings. The simplicity and durability of the design

allows users who are not "computer literate" to easily perform routine tasks such as changing ribbons and

correcting paper jams. Some companies, such as Printek, DASCOM, WeP Peripherals, Epson, Okidata, Olivetti,

Lexmark, and TallyGenicom still produce serial and line printers. Today, a new dot matrix printer actually costs

more than most inkjet printers and some entry level laser printers. However, not much should be read into this

price difference as the printing costs for inkjet and laser printers are a great deal higher than for dot matrix printers,

and the inkjet/laser printer manufacturers effectively use their monopoly over arbitrarily priced printer cartridges to

subsidise the initial cost of the printer itself. Dot matrix ribbons are a commodity and are not monopolised by the

printer manufacturers themselves.

[edit]Advantages and disadvantages

This section does not cite any references or sources.Please help improve this article by adding citations to reliable sources. Unsourced material may be challenged andremoved. (May 2010)

[edit]Advantages

Dot matrix printers, like any impact printer, can print on multi-part stationery or make carbon-copies. Impact

printers have one of the lowest printing costs per page. As the ink is running out, the printout gradually fades rather

than suddenly stopping partway through a job. They are able to use continuous paper rather than requiring

individual sheets, making them useful for data logging. They are good, reliable workhorses ideal for use in

situations where printed content is more important than quality. The ink ribbon also does not easily dry out,

including both the ribbon stored in the casing as well as the portion that is stretched in front of the print head; this

unique property allows the dot-matrix printer to be used in environments where printer duty can be rare, for

instance, as with a Fire Alarm Control Panel's output.

[edit]Disadvantages

Impact printers create noise when the pins or typeface strike the ribbon to the paper. Sound dampening enclosures

may have to be used in quiet environments. They can only print lower-resolution graphics, with limited color

performance, limited quality, and lower speeds compared to non-impact printers. While they support fanfold paper

with tractor holes well, single-sheet paper may have to be wound in and aligned by hand, which is relatively time-

consuming, or a sheet feeder may be utilized which can have a lower paper feed reliability. When printing labels

on release paper, they are prone to paper jams when a print wire snags the leading edge of the label while printing

at its very edge. For text-only labels (e.g., mailing labels), a daisy wheel printer or band printer may offer better

print quality and a lesser chance of damaging the paper.

IBM Selectric typewriterFrom Wikipedia, the free encyclopedia

  (Redirected from Golf ball printer)

"Selectric" redirects here. For the record label, see Selectric Records.

IBM Selectric

The IBM Selectric typewriter (occasionally known as the IBM Golfball typewriter) was a highly successful model

line of electric typewriters. It was introduced in 1961.[1]

Instead of a "basket" of pivoting typebars the Selectric had a pivoting type element (frequently called a "typeball")

that could be changed so as to display different fonts in the same document, resurrecting a capacity that had been

pioneered by theBlickensderfer typewriter sixty years before. The Selectric also replaced the traditional typewriter's

moving carriage with a paper roller ("platen") that stayed in position while the typeball and ribbon mechanism

moved from side to side.

Selectrics and their descendants eventually captured 75 percent of the United States market for electric typewriters

used in business.[2]

Contents

 [hide]

1   Features and uses

2   Design

3   Selectric II

4   Ribbons

5   Selectric-based machines with data storage

6   Selectric Composers

7   Selectric III

8   Elements and fonts

o 8.1   Small (12-pitch) fonts

o 8.2   Large (10-pitch) fonts

9   The Selectric as computer terminal

10   The Selectric in popular culture

11   References

12   Patents

13   External links

[edit]Features and uses

IBM typeballs (one OCR) with clip, €2 coin for scale

The ability to change fonts, combined with the neat regular appearance of the typed page, was revolutionary, and

marked the beginning of desktop publishing. Later models with dual pitch (10/12) and built-in correcting tape

carried the trend even further. Any typist could produce a polished manuscript. By 1966, a full typesetting version

with justification and proportional spacing was released.

The possibility to intersperse text in Latin letters with Greek letters and mathematical symbols made the machine

especially useful for scientists writing manuscripts that included mathematical formulas. The typical look of

Selectric typed documents is hence still familiar to any scientist who reads conference

proceedings, monographs, theses and the like from these times. (Proper mathematical typesetting was very

laborious before the advent of TeX and done only for much-sold textbooks and very prestigious journals.)

The machine had a feature called "Stroke Storage" that prevented two keys from being depressed simultaneously.

When a key was depressed, an interposer, beneath the keylever, was pushed down into a slotted tube full of small

metal balls (called the "compensator tube") and spring latched. These balls were adjusted to have enough

horizontal space for only one interposer to enter at a time. (Mechanisms much like this were used in keyboards for

teleprinters before World War II.) If a typist pressed two keys simultaneously both interposers were blocked from

entering the tube. Pressing two keys several milliseconds apart allows the first interposer to enter the tube, tripping

a clutch which rotated a fluted shaft driving the interposer horizontally and out of the tube, making way for the

second interposer to enter the tube some milliseconds later. While a full print cycle was 65 milliseconds this

filtering and storage feature allowed the typist to depress keys in a more random fashion and still print the

characters in the sequence entered. The powered horizontal motion of the interposer selected the appropriate

rotate and tilt of the printhead for character selection.

The spacebar, dash/underscore, index, backspace and line feed repeated when continually held down. This

feature was referred to as "Typamatic."

The Selectric mechanism was notable for using internal mechanical binary coding and two mechanical binary-

digital-to-analog converters, the "whiffletree" linkages described below, to select the character to be typed.

[edit]Design

IBM Selectric I

The Selectric typewriter was introduced on 23 July 1961. Its industrial design is credited to influential American

designer Eliot Noyes. Noyes had worked on a number of design projects for IBM; prior to his work on the Selectric,

he had been commissioned in 1956 by Thomas J. Watson, Jr to create IBM's first house style — these influential

efforts, in which Noyes collaborated with Paul Rand, Marcel Breuer, and Charles Eames, have been referred to as

the first "house style" program in American business.[2]

Both Selectric and the later Selectric II were available in standard, medium, and wide-carriage models and in

various colors, including red and blue as well as traditional neutral colors.

Mechanically, the Selectric borrowed some design elements from a toy typewriter produced earlier by Marx Toys.

IBM bought the rights to the design.[3] The typeball and carriage mechanism was similar to the design of the

Teletype Model 26 and later, which used a rotating cylinder that moved along a fixed platen.[4]

The mechanism that positions the typing element ("ball") is partly binary, and includes two mechanical digital-to-

analog converters, which are basically "whiffletree" linkages of the type used for adding and subtracting in linkage-

type mechanical analog computers. Every character has its own binary codes, one for tilt and one for rotate.

When the typist presses a key, it unlatches a metal bar for that key. The bar is parallel to the side of the

mechanism. This bar has several short projections ("fingers"). Only some of the fingers are present on any given

code bar, those present corresponding to the binary code for the desired character.

When the key's bar moves, its projections push against a second set of bars that extend all the way across the

keyboard mechanism; each bar corresponds to one bit. All bars for the keys contact some of these crosswise bars.

Those bars that move, of course, define the binary code.

The bars that have been moved cause cams on the driveshaft (which is rotating) to move the ends of the links in

the whiffletree linkage, which sums (adds together) the amounts ("weights") of movement corresponding to the

selected bits. The sum of the weighted inputs is the required movement of the typing element. There are two sets

of similar mechanisms, one for tilt, one for rotate. The reason for this is the type element has four rows of 22

characters. By tilting and rotating the element to the location of a character, the element can be thrust against the

ribbon and platen, leaving an imprint of the chosen character.

The motor at the back of the machine drove a belt connected to a two-part shaft located roughly halfway through

the machine. The Cycle Shaft on the left side provided the energy that was used to tilt and rotate the type element.

The Operational Shaft on the right side provided functions such as spacing, back spacing and case shifting.

Additionally, the Op Shaft was used as a governor; limiting the left-to-right speed with which the carrier moved. A

series of spring clutches were used to power the cams which provided the motion needed to perform functions

such as backspacing. The Cycle Shaft was rotated when a spring clutch was released, driving a set of cams

whose rotational motion was then converted into left-and-right motion by the whiffle tree. The system was highly

dependent upon lubrication and adjustment and much of IBM's revenue stream came from the sale of Service

Contracts on the machines. Repair was fairly expensive, so maintenance contracts were an easy sell.

The locations of the characters on the element were not random. Punctuation marks and the underscore were

deliberately placed so the maximum amount of energy was used to position the element, thus reducing the impact

made by them and lessening the chance that the underscore would cut through the paper. Later on, a deliberate

mechanism was added that reduced the force of the impact made by punctuation.

Tilt and rotate movements are transferred to the ball carrier, which moves across the page, by two taut metal

tapes, one for tilt and one for rotate. The tilt and rotate tapes are both anchored to the right side of the carrier (the

mechanism that supports the type element). They both wrap around separate pulleys at the right side of the frame.

They then extend across the machine behind the carrier, and then wrap around two separate pulleys at the left

side of the frame. The tilt tape is then anchored to a small, quarter-circle pulley which, through a gear, tips the tilt

ring to one of four possible locations (The tilt ring is the device to which the type element is connected). The rotate

tape is wrapped around a spring-loaded pulley located in the middle of the carrier. The rotate pulley under the tilt

ring is connected through a universal joint (called a "dog bone"; it looked like a small bone) to the center of the tilt

ring. The type element is spring-latched onto that central post. The type element rotates counter-clockwise when

the rotate tape is tightened. The spiral "clock" spring underneath the rotate pulley rotates the element in the

clockwise direction. As the carrier moves across the page (such as when it returns), the tapes travel over their

pulleys, but the spring-loaded pulleys on the ball carrier do not pivot or rotate.

To position the ball, both of the pulleys on the left side of the frame are moved by the whiffletree linkage. When the

rotate pulley is moved to the right or left, the rotate tape spins the type element to the appropriate location. When

the tilt pulley is moved, it tips the tilt ring to the appropriate location. When it moves, the tape rotates the spring-

loaded pulley on the ball carrier independent of the carrier's location on the page.

Case was shifted between caps and lower case by rotating element by exactly half a turn. This was accomplished

by moving the right-hand rotate pulley using a cam mounted on the end of the operation shaft.

There was a proportional-spacing Selectric called a Composer that would backspace proportionally for perhaps 40

characters. The spacing code for the last characters typed was stored by small sliding plates in a carrier wheel.

[edit]Selectric II

IBM Selectric II (dual Latin/Hebrew typeball and keyboard)

Selectric II dual Latin/Hebrew Hadartypeball

After the Selectric II was introduced in 1971 [2], the original design was designated the Selectric I. These

machines used the same 88-character typing elements. However they differed from each other in many respects:

The Selectric II was squarer at the corners, whereas the Selectric I was rounder.

The Selectric II had a Dual Pitch option to allow it to be switched (with a lever at the top left of the

"carriage") between 10 and 12 characters per inch, whereas the Selectric I had one fixed "pitch."

The Selectric II had a lever (at the top left of the "carriage") that allowed characters to be shifted up to a

half space to the left (for centering text, or for inserting a word one character longer or shorter in place of a

deleted mistake), whereas the Selectric I did not. This option was available only on dual pitch models.

The Correcting Selectric II was announced in 1973 and had a correction feature. This worked in

conjunction with a correction ribbon: Either the transparent and slightly adhesive "Lift-Off" tape (for use with

Correctable Film ribbons), or the white "Cover-Up" tape (for cloth or Tech-3 ribbons).

The white or transparent correction tape was at the left of the typeball and its orange take-up spool at the

right of the typeball; it was changed independently from the typing ribbon. The correction key (an extra

key at the bottom right of the keyboard) backspaced the carriage by one space and also put the machine

in a mode wherein the next character typed would use the correction tape instead of the normal ribbon,

and furthermore would not advance the carriage. The typist would press (and release) the correction key

and then re-type the erroneous character, either lifting it off of the page or (if using a fabric ribbon)

covering it with white-out powder, then type the correct character. Any number of mistakes could be

corrected this way, but the process was entirely manual, as the machine had no memory of the typed

characters.

[edit]Ribbons

In addition to the "typeball" technology, Selectrics were also associated with a series of innovations in ribbon

design. The original Selectric had to be ordered to use either cloth reusable ribbon or one-time carbon film

ribbon; the same machine could not use both. The same was true of the original, non-correcting Selectric II.

IBM had used a similar carbon film ribbon on their earlier "Executive" series of typewriters. As with these

older machines, the carbon film ribbon presented a security issue in some environments: It was possible to

read the text that had been typed from the ribbon, seen as light characters against the darker ribbon

background.

The "Correctable" nature of the Correcting Selectric II's carbon film ribbons had an additional issue in that

the carbon pigment could easily be removed from a typed document, thus facilitating unauthorized changes.

The Correcting Selectric II used a new ribbon cartridge mechanism. The ribbons were wider than had been

used previously, giving more typed characters per inch of ribbon. Successive characters were staggered

vertically on the ribbon, which incremented less than a full character position each time. Any Correcting

Selectric II could use any of three types of ribbon, which all came in similar-looking cartridges: Reusable

cloth ribbon with associated Cover-Up tape; Correctable (carbon) Film ribbon with associated Lift-Off tape;

and the Tech-3 permanent ribbon, introduced later, which used the same Cover-Up tape as the earlier cloth

ribbon. The Tech-3 ribbon essentially replaced the cloth ribbon, as they offered similar typing quality

equivalent to the film ribbon but at a cost comparable to the reusable cloth.

Tech-3 ribbons provided much higher security and longer life than the Correctable Film ribbon. Like the cloth

ribbon, Tech-3 ribbons incremented only a fraction of the character width after being struck. Unlike the cloth

ribbon, the Tech-3 ribbon provided high quality impressions for several characters from each spot on the

one-time-use ribbon. Because characters overstrike each other on a Tech-3 ribbon several times it could not

be easily read to discover what had been typed.

In addition, where the Correctable Film ribbon was unsuitable for documents such as checks due to the

ease of lifting the ink from the document, the Tech-3 ribbon's impressions were permanent as soon as they

were struck. Some colored ribbons (e.g. brown) were also available.

There were four classes of carbon film ribbons available for the Selectric II series. The thumb wheel on the

ribbon and the correction tape spools were color coded so they could be easily identified and matched with

the appropriate correction tapes. There were two lift-off correctable ribbons/correction tapes, one color

coded yellow and the other orange. Yellow meant the ribbon was a higher quality and would produce a

better quality type image. Orange was a general purpose ribbon for everyday typing. The yellow and orange

coded lift-off tapes would work with either ribbon type because they were both sticky (similar to adhesive

tape) and would pull the ink off the paper. Later there was a less "sticky" version of these lift-off tapes that

wouldn't damage more delicate paper surfaces, but some people believed it didn't remove the ink as well. As

a side note, if you ran out of lift-off tape, you could use a piece of adhesive tape (such as Scotch tape) to

correct a mistake.

The Tech-3 (Tech III) ribbons described above were color coded blue and the high quality carbon film ribbon

was color coded pink. The pink coded ribbons could be used for the more sensitive documents because the

ink was not easily removable from the paper and it gave a clearer/crisper image than the Tech-3 ribbons.

The correction tapes for these covered up the typewritten characters with white ink. This complicated

corrections on paper colors other than white.

[edit]Selectric-based machines with data storage

IBM Magnetic Card

In 1964 IBM introduced the "Magnetic Tape Selectric Typewriter" and in 1969, a "Magnetic Card Selectric

Typewriter." These were sometimes referred to as the "MT/ST" and "MC/ST", respectively. The MC/ST was

also available in a "communicating" version that could emulate anIBM 2741 terminal or run its native

Correspondence Code. These featured electronically-interfaced typing mechanisms and keyboards and a

magnetic storage device (either tape in a cartridge, or a magnetic-coated card the same size as an 80-

column punched card) for recording, editing, and replaying typed material at ca. 12-15 characters per

second.

These machines were among the first to provide word processing capability in any form. They used the

same elements as ordinary office Selectrics.

IBM also sold a tape reader that could be connected to 360 series mainframes, and would read the MT/ST

tapes. Thus a document typed on an MT/ST Selectric could also be entered into a mainframe data file.

[edit]Selectric Composers

Sample of IBM Magnetic Card Composer output (Press Roman 10pt font family)

In 1966, IBM released the Selectric Composer. This highly modified[5] Selectric produced camera-ready

justified copy using proportional fonts in a variety of font styles from 8pt to 14pt. Material prepared on a

properly adjusted machine by a skilful operator and output onto baryta (barium-sulphate-coated) paper

"would take an expert to tell ...was not the product of a Linotype or Monotype machine".[6]

Like the Varityper with which it competed, the original machine required that material be typed twice if the

type was to be justified. The first time was to measure the length of the line and count the spaces, recording

special measurements on the right margin. The second time it was typed, the operator used the

measurements to set justification for each line. The process was tedious and lengthy but provided a way to

get camera-ready, proportionally spaced, justified copy from a desktop machine. The elements for the

Selectric Composer would physically fit on a Selectric, and vice versa, but they could not actually be used on

each other's machines: the characters were arranged differently around the element and were also

positioned differently within each character area. Selectric Composer elements can be identified by a

colored index arrow (the color is used to set a median character width on the machine) and an abbreviated

series of letters and numbers identifying the font, size, and variation, for example "UN-11-B" for Univers 11

point bold (Adrian Frutiger had adapted his Univers font specifically for the Selectric Composer[7]).

In 1967, a "Magnetic Tape Selectric Composer" appeared, and in 1978, a "Magnetic Card Selectric

Composer." The "Electronic Composer" (with c. 5000 characters internal memory and similar to the later

Magnetic Card model but without external storage) was marketed from 1975. All these models used the

same elements and measurement mechanism as the previous Selectric Composer. However, due to the

magnetic/internal storage, they avoided the need to type justified text twice or to set the mechanism for the

justification needs of each line. Furthermore, tapes or cards originally recorded on the much less expensive

and easier to operate Selectric typewriter versions, the MT/ST or MC/ST, could be read by the "Composer"

equivalents.

[edit]Selectric III

In the 1980s IBM introduced a Selectric III and several other Selectric models, some of them word

processors or typesetters instead of typewriters, but by then the rest of the industry had caught up with the

trend, and IBM's new models did not dominate the market the way the first Selectric had. This was to be

expected, as by the late 1970s the Selectric typewriter's dominance was under assault from both 35-45

character per second proportional-spacing electronic typewriters with inbuilt memory (e.g. the 800

from Xerox based on Diablo's 'daisywheels' and from OEMs of Qume who had a similar 'printwheel'

technology) and CRT-based systems from AES, Lexitron, Vydek, Wang and Xerox (see the Word

Processor article for further details of these brands). In addition, IBM had already (c. 1977) brought to

market the CRT-based Office System/6 (from Office Products Division)[8] and 5520 [9] (from IBM GSD) both

of which used the new 6640 inkjet printer capable of 96 characters per second with two paper trays and

sophisticated envelope handling, and was about to introduce Qume-based printers for the existing System/6

range and the new Displaywriter [10]  launched in June 1980 and described by IBM as "not your father's

Selectric."

Nevertheless, IBM had a large installed base of Selectric typewriters and to retain customer loyalty it made

sense to introduce updated models.

The Selectric III featured a 96 character element vs. the previous 88 character element. IBM's series of

"Electronic Typewriters" used this same 96 character element. The 96 character elements can be identified

by yellow printing on the top plastic surface and the legend "96," which always appears along with the font

name and pitch. The 96 and 88 character elements are mechanically incompatible with each other (they

won't fit on each others' machines) and 96 character elements were not available in as many fonts as the

older 88 character types.

Most Selectric IIIs and Electronic Typewriters only had keys for 92 printable characters; the 96 character

keyboard was an optional feature. Fitting the additional keys onto the keyboard required shrinking of the

Return key and this was annoying to many typists, so it was not the default configuration. The keytops on

the Selectric III and Electronic Typewriters were larger and more square than those on earlier Selectrics.

[edit]Elements and fonts

The Selectric I, Selectric II, and all of the "Magnetic Card" and "Magnetic Tape" variations except for the

Composers, used the same typing elements. These were available in many fonts, including symbols for

science and mathematics, OCR faces for scanning by computers,cursive script, "Old English" (fraktur), and

more than a dozen ordinary alphabets. The Israeli typographer Henry Friedlaender designed the Hebrew

fonts Hadar, Shalom & Aviv for the Selectric. The Selectric III and "Electronic Typewriters" used a new 96-

character element.

IBM also produced computer terminals based on the Selectric mechanism, some of which (all models of the

IBM 1050 series, and IBM 2741models using "PTTC/BCD" code) used a different encoding. Though the

elements were physically interchangeable, the characters were differently arranged, so that standard

Selectric elements could not be used in them, and their elements could not be used in standard Selectrics.

On the other hand, IBM 2741s using "correspondence coding" used standard office Selectric elements.

There were two visibly different styles of mechanical design for the elements. The original models had a

metal spring clip with two wire wings that were squeezed together to release the element from the

typewriter. Later models had a fragile flip-up black plastic lever that could break off. This was later

redesigned to have a substantial plastic lever that did not break.

Some of the interchangeable font elements available for the Selectric models included:

[edit]Small (12-pitch) fonts

Elite 72

Auto Elite

Large Elite (12)

Prestige Elite  72

Prestige Elite 96*

Adjutant

Artisan

Contempo

Courier  (12)

Courier Italic

Courier Italic 96*

Forms

Letter Gothic

Letter Gothic 96*

Light Italic

OCR

Olde World

Oriental

Presidential Elite

Report 96 (12)*

Scribe

Scribe 96*

Script

Symbol

[edit]Large (10-pitch) fonts

Pica 72

Prestige Pica 72

Pica 96*

Advocate

Boldface

Bookface Academic 72

Business Script

Courier (10)

Courier 96 (10)

Bold Courier (10)

Delegate

Delegate 96*

Manifold

Orator

Sunshine Orator

Orator 96*

Orator Presenter

Presidential Pica

Report 96 (10)*

Title

Starred fonts were 96-character elements made for the Selectric III.

Many of the fonts listed here came in several sub-varieties. For example, in the early years of the Selectric,

typists were used to using the lower-case L for the numeral 1. The Selectric had a dedicated key for 1/!, but

this was also marked [/], and many of the early elements had square brackets in these positions,

necessitating that the typist continue the old convention. Later elements tended to have the dedicated

numeral 1 and exclamation point characters instead. Some moved the square brackets to the positions

formerly occupied by the 1/4 and 1/2 fractions, while others lost them completely. Some put a degree

symbol in place of the exclamation point. IBM would furthermore customize any element for a fee, so literally

endless variations were possible. Such customized elements were identified by a gray plastic flip-up clip

instead of a black one.

Many specialized elements were not listed in IBM's regular brochure, but were available from IBM provided

the right part number was known. For example, the element for the APL programming language was

available. This element was really intended for use with the IBM 2741printing terminal.

[edit]The Selectric as computer terminal

Due to their speed (14.8 characters per second), immunity to clashing typebars, trouble-free paper path,

high quality printed output, and reliability, Selectric-based mechanisms were also widely used as terminals

for computers, replacing both Teletypes and older typebar-based output devices. One popular example was

the IBM 2741 terminal, which figured prominently in the early years of the APL programming language.

Despite appearances, these machines were not simply Selectric typewriters with an RS-232 connector

added. As with other electric typewriters, and electric adding machines of the era, Selectrics are best

thought of as electromechanical devices: The only electric components are the power cord, power switch,

and electric motor. The electric motor runs continuously. The keys are not electrical pushbuttons, as they

are on a computer keyboard. Pressing a key does not produce an electrical signal, but rather engages a

series of clutches which couple the motor power to the mechanism to turn and tilt the element. A Selectric

would work equally well if hand-cranked at sufficient speed.

Adapting this mechanism to the needs of computer input/output was nontrivial. Microswitches were added to

the keyboard, solenoids were added to allow the computer to trigger the typing mechanism, and interface

electronics were needed. Several mechanical components, in particular the motor and the main clutch, had

to be upgraded from the typewriter versions to reliably support continuous operation. Additional

microswitches had to be added to sense the state of various parts of the mechanism, such as case (upper

vs. lower).

Even after adding all those solenoids and switches, getting a Selectric to talk to a computer was a large

project. The Selectric mechanism, as documented in its service manual, had many peculiar requirements. If

commanded to shift to upper case when it was already in upper-case, the mechanism locked up and never

signaled "done." The same applied to shifting the ribbon direction or initiating a carriage-return. These

commands could only be issued at particular times, with the Selectric in a particular state, and then not

again until the terminal signaled the operation was complete.

In addition the Selectric spoke neither ASCII nor EBCDIC, but a unique code based on the tilt/rotate

commands to the golf ball. That and the bit-parallel interface and peculiar timing requirements meant the

Selectric could not be directly hooked up to a modem. Indeed it needed a relatively large amount of logic to

reconcile the two devices.

Particularly vexing was the Selectric's lack of a full ASCII character set. The late Bob Bemer wrote[3] that

while working for IBM he lobbied unsuccessfully to expand the typing element to 64 characters from 44. The

Selectric actually provided 44 characters per case, but the point remains that with 88 printable characters it

could not quite produce the full printable ASCII character set.

Nevertheless, between 1968 and about 1980, a Selectric-based printer was a relatively inexpensive and

fairly popular way to get high-quality output from a computer.

Similar machines such as the IBM 1050 series were used as the console printers for many computers, such

as the IBM 1130 and the IBMSystem/360 series. The IBM 1050 was also offered in a remote terminal

configuration, similar in use to the 2741. These were designed and manufactured for this purpose, including

the necessary electrical interfaces, and incorporated more ruggedized components than the office Selectric

or even the 2741.

The 96-character element introduced with the Selectric III and Electronic Typewriter series could (with some

customizations) handle the full ASCII character set, but by that time the computer industry had moved on to

the much faster and simpler daisy wheel mechanisms such as the Diablo 630. The typewriter industry

followed this trend shortly afterward, even IBM replacing their Selectric lineup with the daisy wheel-based

"Wheelwriter" series.

Line printerFrom Wikipedia, the free encyclopedia

This article needs additional citations for verification.Please help improve this article by adding reliable references. Unsourced material may be challenged and removed.(February 2010)

IBM 1403 line printer, the classic line printer of themainframe era.

The line printer is a form of high speed impact printer in which one line of type is printed at a time. They are mostly associated with the early days of computing, but the technology is still in use. Print speeds of 600 to 1200 lines-per-minute (approximately 10 to 20 pages per minute) were common.

Contents

 [hide]

1   Designs

o 1.1   Drum printer

o 1.2   Chain (train) printer

1.2.1   Band printer

o 1.3   Bar printer

o 1.4   Comb printer

2   Paper (forms) handling

3   Origins

4   Current applications

5   See also

6   References

[edit]Designs

Four principal designs existed:

Drum printers

Chain (train) printers

Bar printers

Comb printers

[edit]Drum printer

Drum Printer

Fragment of line printer drum

showing "%" characters.

In a typical drum printer design, a fixed font character set is engraved onto the periphery of a number of print

wheels, the number matching the number of columns (letters in a line) the printer could print. The wheels, joined to

form a large drum (cylinder), spin at high speed and paper and an inked ribbon is stepped (moved) past the print

position. As the desired character for each column passes the print position, a hammer strikes the paper from the

rear and presses the paper against the ribbon and the drum, causing the desired character to be recorded on the

continuous paper. Because the drum carrying the letterforms (characters) remains in constant motion, the strike-

and-retreat action of the hammers had to be very fast. Typically, they were driven by voice coils mounted on the

moving part of the hammer.

Often the character sequences are staggered around the drum, shifting with each column. This obviates the

situation whereby all of the hammers fire simultaneously when printing a line that consists of the same character in

all columns, such as a complete line of dashes ("----").

Lower-cost printers did not use a hammer for each column. Instead, a hammer was provided for every other

column and the entire hammer bank was arranged to shift left and right, driven by another voice coil. For this style

of printer, two complete revolutions of the character drum were required with one revolution being used to print all

the "odd" columns and another revolution being used to print all of the "even" columns. But in this way, only half

the number of hammers, magnets, and the associated channels of drive electronics were required.

At least one low-cost printer, made by CDC, achieved the same end by moving the paper laterally while keeping

the hammer bank at rest.

Dataproducts was a typical vendor of drum printers, often selling similar models with both a full set of hammers

(and delivering, for example 600 lines-per-minute of output) and a half set of hammers (delivering 300 LPM).

[edit]Chain (train) printerChain printers (also known as train printers) placed the type on moving bars (a horizontally-moving chain). As

with the drum printer, as the correct character passed by each column, a hammer was fired from behind the paper.

Compared to drum printers, chain printers had the advantage that the type chain could usually be changed by the

operator. A further advantage was that vertical registration of characters in a line was much improved over drum

printers, which needed extremely precise hammer timing to achieve a reasonably straight line of print. By selecting

chains that had a smaller character set (for example, just numbers and a few punctuation marks), the printer could

print much faster than if the chain contained the entire upper- and lower-case alphabet, numbers, and all special

symbols. This was because, with many more instances of the numbers appearing in the chain, the time spent

waiting for the correct character to "pass by" was greatly reduced. Common letters and symbols would appear

more often on the chain, according to the frequency analysis of the likely input. It was also possible to play

primitive tunes on these printers by timing the nonsense of the printout to the sequence on the chain, a rather

primitive piano. IBM was probably the best-known chain printer manufacturer and the IBM 1403 is probably the

most famous example of a chain printer.

Fragment of printer band, sitting on test printout for the characters (top) and hammer flight times (bottom)

[edit]Band printer

Band printers are a variation of chain printers, where a thin steel band is used instead of a chain, with the

characters embossed on the band. Again, a selection of different bands were generally available with a different

mix of characters so a character set best matched to the characters commonly printed could be

chosen. Dataproducts was a well known manufacturer of band printers, with their B300, B600, and B1000 range,

the model number representing the lines per minute rate of the printer. (The B300 was effectively a B600 with only

half the number of hammers—one per two character positions. The hammer bank moved back and forth one

character position, requiring two goes to print all characters on each line.)

[edit]Bar printer

Bar printers were similar to chain printers but were slower and less expensive. Rather than a chain moving

continuously in one direction, the characters were on fingers mounted on a bar that moved left-to-right and then

right-to-left in front of the paper. An example was the IBM 1443.

In all three designs, timing of the hammers (the so called "flight time") was critical, and was adjustable as part of

the servicing of the printer. For drum printers, incorrect timing of the hammer resulted in printed lines that

wandered vertically, albeit with characters correctly aligned horizontally in their columns. For train and bar printers,

incorrect timing of the hammers resulted in characters shifting horizontally, albeit on vertically-level printed lines.

Most drum, chain, and bar printers were capable of printing up to 132 columns, but a few designs could only print

80 columns and some other designs as many as 160 columns.

[edit]Comb printer

Comb printers, also called line matrix printers, represent the fourth major design. These printers were a hybrid

of dot matrix printing and line printing. In these printers, a comb of hammers printed a portion of a row of pixels at

one time (for example, every eighth pixel). By shifting the comb back and forth slightly, the entire pixel row could

be printed (continuing the example, in eight cycles). The paper then advanced and the next pixel row was printed.

Because far less printhead motion was involved than in a conventional dot matrix printer, these printers were much

faster than dot matrix printers and were competitive in speed with formed-character line printers while also being

able to print dot-matrix graphics as well as variable-sized characters.

Printronix and TallyGenicom are well-known vendors of comb printers.

Because all of these printing methods were noisy, lineprinters of all designs were enclosed in sound-absorbing

cases of varying sophistication.

[edit]Paper (forms) handling

All line printers used paper provided in boxes of continuous fan-fold forms rather than cut-sheets. The paper was

usually perforated to tear into cut sheets if desired and was commonly printed with alternating white and light-

green areas, allowing the reader to easily follow a line of text across the page. This was the iconic "green

bar" form that dominated the early computer age. Pre-printed forms were also commonly used (for

printing cheques, invoices, etc.). A common task for the system operator was to change from one paper form to

another as one print job completed and another was to begin. Some lineprinters had covers that opened

automatically when the printer required attention.

Standard "green bar" page sizes included portrait-format pages of 8½ × 11 inches, usually printed at 80 columns

by 66 lines (at 6 lines per inch) or 88 lines (at 8 LPI), and landscape-format pages of 14 × 11 inches, usually

printed at 132 columns by 66 or 88 lines. Also common were landscape-format pages of 14 × 8½ inches, allowing

for 132 columns by 66 lines (at 8 LPI) on a more compact page.

These continuous forms were advanced through the printer by means of tractors (sprockets or sprocket belts).

Depending on the sophistication of the printer, there might simply be two tractors at the top of the printer (pulling

the paper) or tractors at the top and bottom (thereby maintaining paper tension within the printer). The horizontal

position of the tractors was usually adjustable to accommodate different forms. The earliest printers by IBM used a

hydraulic motor to move the forms. In later line printers, High-speed servomechanisms usually drove the tractors,

allowing very rapid positioning of the paper, both for advancing line-by-line and slewing to the top of the next form.

The faster line printers, of necessity, also used "stackers" to re-fold and stack the fan-fold forms as they emerged

from the printer.

The high-speed motion of the paper often developed large electrostatic charges. Line printers frequently used a

variety of discharge brushesand active (corona discharge-based) static eliminators to discharge these

accumulated charges.

Many printers supported ASA carriage control characters which provided a limited degree of control over the

paper, by specifying how far to advance the paper between printed lines. Various means of providing vertical

tabulation were provided, ranging from punched paper tape to fully electronic (software-controllable) tab simulation

[edit]Origins

The first line printer was the "Potter Flying Typewriter", in 1952. "Instead of working laboriously, one character at a

time, it prints whole lines at once, 300 lines per minute, on a paper band. ... Heart of the machine is a continuously

spinning disk with the necessary letters and numbers on its rim. ... As the disk revolves, 80 electrically operated

hammers tap the back of the paper against an inked ribbon in contact with the disk, thus printing the proper

characters in the proper places on the line." [1]

[edit]Current applications

This technology is still in use in a number of applications. It is usually both faster and has lower total cost of

ownership, including purchase price, consumables, paper, and maintenance, than laser printers. Line printers

continue to be used for printing box labels, medium volume accounting and other large business applications.

Multi-part paper forms (carbon copies or carbonless copy paper) printed in one operation are sometimes useful.

The limited character set, fixed character spacing, and relatively poor print quality make impact line printers

unsuitable for correspondence, books, and other applications requiring high print quality.

Laser printers became popular when word processing replaced typewriters. In high volume printing, continuous

form laser printers have become popular. These no longer had fixed columns or monospaced type and offered a

range of fonts as well as graphics. The technology operates in a way similar to single sheet laser printing.

The names of the lp and lpr commands in Unix were derived from the term "line printer". Analogously, many

other systems call their printing devices "LP", "LPT", or some similar variant, whether these devices are in fact line

printers or other types of printers. These references served to distinguish formatted final output from normal

interactive output from the system, which in many cases in line printer days was also printed on paper (as by

a teletype) but not by a line printer.

Dye-sublimation printerFrom Wikipedia, the free encyclopedia

This article does not cite any references or sources.Please help improve this article by adding citations to reliable sources. Unsourced material may be challenged andremoved. (November 2008)

Samsung SPP-2040 printing a photograph.Part of the series on the

History of printing

Woodblock printing 200

Movable type 1040

Printing press 1454

Lithography 1796

Laser printing 1969

Thermal printing circa 1972

A dye-sublimation printer (or dye-sub printer) is a computer printer which employs a printing process that uses

heat to transfer dye onto a medium materials such as a plastic card, paper, or fabric. The sublimation name is

applied because the dye transitions between the solid and gas states without going through a liquid stage.

Many consumer and professional dye-sublimation printers are designed and used for

producing photographic prints.

Most dye-sublimation printers use CMYO (cyan, magenta, yellow and overcoating) colors, which differs from the

more recognized CMYK colors in that the black dye is eliminated in favour of a clear overcoating. This overcoating (which has numerous names depending on the manufacturer) is also stored on the ribbon and is effectively a thin laminate which protects the print from discoloration from UV light and the air, while also rendering the print water-resistant.

Contents

 [hide]

1   Operation

2   Comparison with inkjet printers

3   Applications

4   Print speed

5   Inks

6   References

7   See also

[edit]Operation

The most common process lays one color at a time, the dye being stored on a cellophane ribbon that has each

color on a separate panel. Each colored panel is the size of the medium that is being printed on; for example, a 6"

by 4" dye sub printer would have four 6" by 4" panels.

During the printing cycle, the printer rollers will move the medium and one of the colored panels together under a

thermal printing head, which is usually the same width as the shorter dimension of the print medium. Tiny heating

elements on the head change temperature rapidly, laying different amounts of dye depending on the amount of

heat applied. After being heated into a gas, the dye diffuses onto the printing medium and solidifies.

After the printer finishes covering the medium in one color, it winds the ribbon on to the next color panel and

partially ejects the medium from the printer to prepare for the next cycle. The entire process is repeated four times

in total: the first three lay the colors onto the medium to form a complete image, while the last one lays the

laminate over top. This layer protects the dye from resublimating when handled or exposed to warm conditions.

[edit]Comparison with inkjet printers

Traditionally, the advantage of dye-sublimation printing has been the fact that it is a continuous-tone technology,

where each dot can be any color. In contrast, inkjet printers can vary the location and size of ink droplets, a

process called dithering, but each drop of ink is limited to the colors of the inks installed. Consequently, a dye-

sublimation printer produces true continuous tones appearing much like a chemical photograph. An inkjet print is

composed of droplets of ink layered and scattered to simulate continuous tones, but under magnification the

individual droplets can be seen. In the early days of inkjet printing, the large droplets and low resolution made

inkjet prints significantly inferior to dye-sublimation, but today's inkjets produce extremely high quality prints using

microscopic droplets and supplementary ink colors, producing superior color fidelity to dye-sublimation.

Dye sublimation offers some advantages over inkjet printing. For one, the prints are dry and ready to handle as

soon as they exit the printer. Since the thermal head doesn't have to sweep back and forth over the print media,

there are fewer moving parts that can break down. As the dye never enters a liquid phase, the whole printing cycle

is extremely clean; there are no liquid inks to clean up. These factors make dye-sublimation generally a more

reliable technology over inkjet printing.

Dye-sublimation printers have some drawbacks compared to inkjet printers. Each of the colored panels of the

ribbons, and the thermal head itself, must match the size of the media that is being printed on. Furthermore, only

specially-coated paper can accept the sublimated ink. This means that dye-sublimation printers cannot match the

flexibility of inkjet printers in printing on a wide range of media. Printheads can also get clogged.

Because the sublimated ink is a gas, it does diffuse a small amount before being absorbed by the paper.

Consequently, prints are not razor-sharp. For photographs, this produces very natural prints, but for other uses

(such as graphic design) this slight blurriness is a disadvantage.

The amount of wasted dye per page is also very high; most of the dye in the four panels may be wasted for a

typical print. Once a panel has been used, even to just print a single dot, the remaining dye on that panel cannot

be reused for another print without leaving a blank spot where the dye was used previously. Due to the single-roll

design of most printers, four panels of colored dye must be used for every print, whether or not a panel is needed

for the print. Printing in monochrome saves nothing, and the three unused color panels for that page cannot be

recycled for a different single-color print. Inkjet printers also suffer from dye wastage, unless they are heavily used,

because the dye dries out in the ink cartridge. Dye-sublimation media packs, (which contain both ribbon and

paper), are rated for an exact number of prints which yields a fixed cost per print. This is in opposition to inkjet

printers where inks are purchased by volume.

For environments that print confidential or secret documents, a dye-sublimation printer is a potential security risk

that must be handled carefully. Due to the mechanism of printing, a perfect color-separated negative image of the

printed page is created on the supply roll color panels, and the "waste roll" of dye panels can be unrolled to see

everything that has been printed with the printer. For such environments the waste roll should be shredded or

incinerated onsite rather than simply being discarded in the trash. Also for home users, the waste roll from a photo

printer can be similarly recovered from the garbage and used to see everything that has been printed. Since the

supply roll is plastic, the lifespan of a used roll can be years or decades long, permitting image recovery long after

disposal.

Also, dye-sublimation papers and ribbons are sensitive to skin oils, which interfere with the dye's ability to

sublimate from the ribbon to the paper. They must also be free of dust particles, which can lead to small colored

blobs appearing on the prints. Most dye-sublimation printers have filters to reduce the likelihood of this happening,

and a speck of dust can only affect one print as it becomes attached to the print during the printing process.

Finally, dye-sublimation printers fall short when producing neutral and toned black and white prints with

higher densitylevels and virtually no metamerism or bronzing.[citation needed]

[edit]Applications

Used dye panels retain a viewable image of the printed document, and an example of wasted dye that cannot be reused.

Previously, the use of dye-sub printing was limited to industrial or high-end commercial printing. Dye-sub photo

printing has been used in medical imaging, graphic arts proofing, security, and broadcast related applications.

Alps Electric produced the first quality dye-sub printers for home consumers in the $500–$1,000 price range,

bringing dye-sublimation technology within the reach of a wider audience. Now there are many dye-sublimation

printers on the market starting from as low as $100 marketed by corporations such as Canon, Sony, Sagem, HiTi

Digital Inc.,DNP Fotolusio, Mitsubishi Electric and Kodak (among others), especiallypostcard-sized mobile photo

printers.

The ability to produce instant photo prints inexpensively from a small printer has led to dye sublimation solutions

supplanting traditional instant photos in some applications, such as with ID photography[1] with a card printer.

Several corporations, including Fuji, ICI, Kodak, DNP, Mitsubishi, and Sony, market desktop size units as stand-

alone printers and for print kiosk and photo boothapplications. Some of these units are based on generic printers

produced by manufacturers such as Shinko. ICI ImageData, Copal, Shinko and Fuji, amongst others,

offer software development kits with their printers, suggesting that these companies hope to attract system

integrators as a potential market. Some units from manufacturers such as HiTi Digital Inc. and Sony incorporate

kiosk features such as display screens and card slots directly into the unit.

Desktop size stand-alone dye-sub photo printers are also being applied by social photographers in event

photography. The units' instant print ability allows photographers to produce and sell lab quality prints immediately

during the event they are attending, with a minimal amount of hardware.

Dye-sublimation printing process is primarily used to print on polyester or other synthetic fabrics. It is used for

many applications such astrade show banners or table covers, t-shirts, bike uniforms, competitive swimwear,

soccer jerseys and flags. The original printers were anelectrostatic technology using toners but now are generally

large format inkjet printers using specially formulated inks. The dye sublimation inks are a pigment suspended in a

liquid solvent, like water. The images are initially printed on coated transfer paper as a reverse image of the final

design, which is then transferred onto polyester fabric in a heat press operating at a temperature around 180 to

210 C (375 F). Under high temperature and pressure, the dye turns into a gas and permeates the fabric and then

solidifies into its fibers. The fabric is permanently dyed so it can be washed without damaging the quality of the

image.

Dye-sublimation can also be used as an indirect printing process. Standard black and white laser printers are

capable of printing on plain paper using a special "transfer toner" containing sublimation dyes which can then be

permanently heat transferred to T-shirts, hats, mugs, metals, puzzles and other surfaces.

Dye-sublimation has many commercial uses. It allows consumers to feature their favourite photos on purses and

totes without the worry of fading, cracking or peeling.

[edit]Print speed

As dye-sublimation printers utilise heat to transfer the dye onto the print media, the printing speed is limited by the

speed at which the elements on the thermal head can change temperature. Heating the elements is easy, as a

strong electric current can raise the temperature of an element very quickly. However, cooling the elements down,

when changing from a darker to a lighter color, is harder and usually involves having a fan/heatsink assembly

attached to the print head. The use of multiple heads can also speed up this process, since one head can cool

down while the another is printing. Although print times vary among different dye-sublimation printers, a typical

cheap home-use dye-sub printer can print a 6" x 4" photo in 45 – 90 seconds. More heavy-duty printers can print

much faster; for example, a Shinko CHC-S-2145 dye-sublimation printer can print a 6" x 4" photo in as little as 6.8

seconds. In all cases, the finished print is completely dry once it emerges from the printer.

[edit]Inks

A disassembled dye sublimation cartridge.

There are two types of dye sublimation inks available in the market. The most popular one is aqueous dye

sublimation ink for use in both desktop and large format printers. The other one is solvent dye sublimation ink that

can be used in XAAR,Spectra [disambiguation needed] and Konica printhead wide format printers.

Due to the fast development of digital textile printing, dye sublimation inks are becoming more and more popular in

digital inkjet printing on fabrics.

List of printer companiesFrom Wikipedia, the free encyclopedia

This is a list of companies who produce or have produced digital printers. This list includes only those companies who have actually designed and manufactured printers, not those who have only offered rebadged products.

Top   A B C D E F G H I J K L M N O P Q R S T U V W X Y Z  References   Notes 

[edit]A

Name Products Status References

A. B. Dick

Advanced Matrix Technology

merged to AMT Datasouth

ALPS

AMT Datasouth

ANZAC

Apple exited printer business

Axonix now know as Mozaex

[edit]B

Name Products Status References

Bell-Mark

Brother

Bull spun off to Compuprint

[edit]C

Name Products Status References

Canon

Centronics acquired by GENICOM

Checkpoint Meto continuous-feed laser became Checkpoint Systemsexited printer business

Citizen serial matrix

Cognitive thermal

Compuprint

Computer Peripherals Inc

merged into Centronics

Comtec Mobile printers acquired by Zebra

Copal acquired by Nidec to form Nidec Copal

Control Data Corporation

printer business merged into Centronics

[edit]D

Name Products Status References

DASCOM serial matrix, thermal, mobile

Dataproducts acquired by Hitachi Kochi

Datasouth merged to AMT Datasouth

Decision Data defunct

Delphax

Diablo acquired by Xerox

Digital Equipment Corporation

printer business acquired by GENICOM

[edit]E

Name Products Status References

Eastman Kodak

Eltron thermal acquired by Zebra

[edit]F

Name Products Status References

Facit defunct

Fargo

Fujitsu

[edit]G

Name Products Status References

GENICOM merged into TallyGenicomairline ticketing business acquired by IER

GCC Printers

General Electric printer business spun off as GENICOM

[edit]H

Name Products Status References

Hitachi printer business acquired by Ricoh

Heidelberg

Hewlett-Packard

[edit]I

Name Products Status References

IBM

[edit]J

Name Products Status References

Juki

[edit]K

Name Products Status References

Kentek LED page printers defunct 2003

Kodak mobile inkjet

Konica merged to Konica Minolta

Konica Minolta

Kyocera Mita

[edit]L

Name Products Status References

Lake Erie Systems

serial matrix

Lexmark serial matrix, laser, inkjet

LiPi Data sys. serial matrix, laser, inkjet, color

[edit]M

Name Products Status References

Mannesmann Tally

leveraged buyout into Tally

Minolta merged to Minolta QMS

Minolta QMS merged to Konica Minola

Memorex Telex became MTX

MTX became Visara

[edit]N

Name Products Status References

Nakajima

NEC printer business acquired by Fuji Xerox in 2001

Nidec Copal dye sublimation printer

Nipson Digital Printing - High Speed - Magnetography

[edit]O

Name Products Status References

Océ

Oki Data

Olivetti

Output Technology

[edit]P

Name Products Status References

Panasonic serial matrix, laser

Pentax mobile inkjet, continuous form laser mobile printer group acquired by Brother

Printer System Corporation

acquired by GENICOM

Printek serial matrix, thermal, mobile

Printer Systems International

serial matrix, continuous form laser

Printronix line matrix, thermal, continuous form laser

PSI Engineering envelope laser c/w feeder, continuous form laser,document automation, folder & feeder finishers

[edit]Q

Name Products Status References

QMS merged to Minolta QMS

Qume daisywheel acquired by Wyse

[edit]R

Name Products Status References

Rank Xerox acquired by Xerox

Ricoh

RISO

RJS thernal acquired by Elton

[edit]S

Name Products Status References

Samsung low-end laser

Seiko

Seiko Epson

Sharp

Siemens Nixdorf

Source Technologies

Swecoin Acquired by Zebra in 2006

Syscan mobile merged to Syscan-IDexited printer business

Star

Star Micronics

[edit]T

Name Products Status References

Tally serial matrix, line matrix, laser merged into TallyGenicom

TallyGenicom serial matrix, line matrix, laser, thermal, mobile

U.S. assets purchased by PrintronixEuropean assets purchased by Dascom

TEC

Tektronix Phaser brand solid ink color printer business acquired by Xerox

Teletype

Texas Instruments

serial matrix, inkjet, low-end laser, airline ticketing

printer business acquired by GENICOM

Toshiba

Trilog color serial matrix acquired by Centronics

TVS Electronics

[edit]U

Name Products Status References

UBI acquired by Intermec

[edit]V

Name Products Status References

Versatec electrostatic plotter acquired by Xerox

[edit]X

Name Products Status References

Xeicon

Xerox

Xerox International Partners(Fuji Xerox)

[edit]W

Name Products Status References

Wipro Technologies

[edit]Z

Name Products Status References

Zebra Label, Mobile, Card and Kiosk Printers. Thermal, Thermal Transfer and Retransfer technolgies.

General printer troubleshooting.Issue

General printer troubleshooting.

Solution

Printer does not have power indicator

First, make sure that the printer is on. When a printer is on it should have some light (usually green) indicating it's receiving power and is on.

If you do not have any indicator light make sure the printer is connected to a working power outlet by verifying each

end of the power cable. Next, press the printer power button.

If after following the above steps your printer still cannot get a power status indicator it's likely you're encountering a serious printer issue and we suggest contacting the printer manufacturer for additional steps and instructions on repair or replacement.

Cables not connected properly

Your printer should have two cables connected to it. The power cable and the data cable, the power cable should have already been verified as being connected if your printer has a power indicator light as mentioned above. Make sure the data cable (parallel cable or USB cable) is also connected from the printer to the computer.

Printer error (orange or blinking light)

After your printer has completed its initial startup you should have a solid green light. If the light indicator is blinking or orange often this is an indication of a printer error. For example, this could indicate a paper jam, issue with the ink or toner cartridge, or other serious error.

Because there is no standard to what a blinking light or orange light means if you're getting either of these we suggest referring to the printer documentation for troubleshooting steps or methods of determining what the status indicator is reporting.

No paper or paper jam

Without paper your printer will not be able to print. Make sure you have paper in the paper loaded into the printer paper cartridge or tray. Next, verify that no printer paper is jammed or partially fed into the printer. If you have one or more pieces of paper stuck in the printer these will need to be manually removed before the printer will print again.

Inkjet printer ink related issues

Often when you're encountering an ink related issue you're printer status indicator light (mentioned above) should be

flashing. If this is not occurring you may want to simply skip to the next section. However, if you've recently inserted a new ink cartridge you may want to try the below suggestions.

See document CH000084 for additional troubleshooting steps that can be taken if your printer no longer works properly after replacing a printers ink cartridge.

Printer self tests

Most printers have a way of printing a test page. This page allows you to determine if the printer is physically working or not. This test is usually accomplished by holding down a series of keys. If you are not sure if your printer has this feature or how to perform it refer to your manual or visit your printer manufacturers web site.

In addition to testing the printer using the printer self-test Microsoft Windows users can also perform a software self-test to determine if their computer is able to see the printer and it's able to print. Follow the below steps to perform this test.

Microsoft Windows 98, 2000, ME, XP, 2003, and Vista users

1. Click Start, Settings, and open Control Panel.2. Double-click the Printers or Printers and Fax icon.

3. Right-click on the Printer you wish to test and click Properties. If you do not see your printer listed your printer is not installed. See document CH000939 for additional information about installing a printer in Windows.

4. In the Printers Properties window click the Print Test Pagebutton.

5. If the printer is able to print a test page, you're printer is installed and setup properly. However, if you're unable to print in other programs it's possible that the program you're attempting to print from has issues.

Older versions of Windows with older printers

If you are running an older printer and MS-DOS, Windows 3.x, Windows 95,Windows 98, or Windows NT, you can also attempt the below software test.

Get to a MS-DOS prompt - Additional information about getting an MS-DOS prompt can be found on document CHDOS.Get to the root directory - Type cd\Reroute dir to printer - Type dir > lpt1

The above should take the directory listing and print to the printer. If this does not print, refer to your operating system troubleshooting section. Extra Note: This will not paper feed, therefore press your FF or PP, or manually eject the paper.

Printer drivers

If your printer does not have any flashing lights and is connected properly it's possible you may be encountering a driver related issue. We suggest visiting our printer driver listing, which links to all major printer manufacturer driver pages and downloading the latest printer drivers for your printer.

Parallel (LPT) printers

If the printer you're connecting to the computer is an LPT (parallel port) printer we also suggest verifying the below suggestions if your printer is not working.

Parallel port in CMOS

1. Enter the computers CMOS setup .2. Once in CMOS verify that your parallel port

is enabled orinstalled.3. Next, verify the printer or parallel port mode. This

option will often have several different modes. If your parallel port is set to ECP mode, we suggest trying a different mode.

Other parallel device

If you have a parallel printer with other parallel devices such as a parallel scanner or zip drive, temporarily

disconnect these devices to verify they are not causing your issue.

The Paper Jam

We have all had this one happen. You are printing merrilyaway when all of a sudden you hear that distinctive crunch of paper gettingeaten by your printer. You immediately cancel the print job, leap from yourdesk and flip open the printer. “Ugh,” you say as you notice the crinkled edgesof paper wrapped around god knows what. Okay, so you have found the problem,but what do you do?

The best way to remove a paper jam is to gently pull thepaper in the direction of the paper path-with power off, of course. Whateveryou do, don not pull the paper backwards. You could damage your printer foreverby doing so!

The Missing Driver

This is another common problem. You are all geared up andready to print but your computer can not find the right driver to “talk to” theprinter. Why is this? Not all drivers are pre-installed on all operating systemsand as new operating systems are released, you will need to install driversyourself. Consult your printer manual. You can also most likely find thecorrect driver online at the printer manufacturer’s website. If not though, asimple web search should help you find what you are looking for. Tryingsearching for your printer manufacturer, the model and “printer driver.”

The Printer Picks Up All the Paper

This is a frustrating one. You are trying to print outsomething and the printer feeds in the whole paper stack rather than just onepiece at a time. For starters, make sure you fan the paper edge before puttingit in the printer feed tray. This helps separate the sheets. Also, be sure tostore your paper in a cool, dry place as humidity can contribute to this peskyproblem.

The Blank Page Syndrome

So you have just installed a new printer ink cartridge andyou print a document only to see a blank page come out. Aggravating, no? Butthis usually has a simple solution. Make sure you completely removed thatlittle sticker from the ink cartridge before installing it. If it is removed,run the clean print head function on your printer to make sure all air bubblesare removed. Just whatever you do, don not remove the cartridge once it is beeninstalled!

The Color and Print Quality is Diminished

This usually happens when one ink well is running low. Ifall of your images start to look a bit purple, blue or orangish, this may beyour problem. The usual solution for this problem is to replace the wholeprinter ink cartridge, unless you can refill the individual ink wells.

Â

The Smudgy Printout

This happens a lot when you print out pages with a lot ofimages with bright, vibrant colors. The cause is usually having the wrong papersetting selected. If you are printing text documents, don not print at thehighest quality. And if you are printing on photo paper, make sure you don notuse the regular printer setting.

The Computer Won not Talk to the Printer

Once you rule out that it is not a printer driver issue,check to make sure you are using the right cables to connect everything. Onceyou confirm everything is connected properly, read your printer manual and yourcomputer manual-at least the part that pertains to printing. Older printersmade for Macs may need a serial cable to work while PC printers an IEEE 1248cable.

The Blinking Light

While there is no surefire answer to this problem, it is acommon enough one that it should be included. Each printer has a differentreason for its dreaded blinking or orange light but some general reasonsinclude a paper jam, a printer cartridge problem or a problem with the printerhardware. It could also be an indicator that the computer is not talking to theprinter. Check your printer manual to see what specific light errors mean foryour model.

The Printout Looks Misaligned

Problems with alignment have a lot to do with maintainingproper print head alignment. You can run a simple diagnostic to fix thisproblem. If the ink seems to be going onto the paper improperly or you noticeuneven coverage, try aligning the print heads before you bring out the bigguns.

The Printout Looks Grainy

This may have nothing to do with the printer at all. In factit may have more to do with the quality of images you are using than the printer@squality. Make sure that when you print photos that they are of print quality,meaning 300dpi. Anything lower than this will appear pixilated and lower thanphoto quality.