Output devices: printers - matrix, inkjet, laser; imagesetter; proofs Output devices: printers (...

Output devices: printers - matrix, inkjet, laser; imagesetter; proofs

Output devices: printers (matrix, inkjet, laser; imagesetter; proofs)


„Output” in cartography before the digital age

Offset printingLithography was initially created to be a low cost method of reproducing artwork. This printing process was limited to use on flat, porous surfaces because the printing plates were produced from limestone (Alois Senefelder, 1771–1834).The first rotary offset lithographic printing press was created in England in 1875. The offset cylinder was covered with specially treated cardboard that transferred the printed image from the stone to the surface of the metal. Later, the cardboard covering of the offset cylinder was changed to rubber.As the 19th century closed and photography captured favor, many lithographic firms went out of business. Photoengraving, a process that used halftone technology instead of illustration, became the leading aesthetic of the era.

Photo: L. Zentai (München)



Photography - phototypesettingPhototypesetting dates back to the 1940s, but the technology became popular in the early 1970s when it replaced hot metal typesetting as offset lithography printing grew in popularity.In Europe, the company of Berthold successfully developed its Diatype (1960), Diatronic (1967), and ads (1977) machines, which led the European high-end typesetting market for decades.

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TypewriterA typewriter is a mechanical or electromechanical device with lots of keys that, when pressed, cause ink to be printed on a medium, usually paper. From their invention before 1870 through much of the 20th century, typewriters were indispensable tools for many people and in business offices. By the end of the 1980s, word processors and personal computers had largely replaced the tasks previously accomplished with typewriters in the western world.The 1874 Sholes & Glidden typewriters established the „QWERTY” layout for the letter keys.

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Copying methodsEfforts to copy existing paper documents began in the 1840s with the development of photosensitive paper.Blue process: the first commercially important process (around 1870) - The blue process was time consuming and impractical for duplication of typical office documents.Camera-based photocopying machines: The prints were made direct on sensitized paper, no negative, plate or film intervening (around 1905). The usual exposure was ten seconds. Exposure – developing bath – fixing – drying.Reflex Copying Machines: Like the blue process, reflex copying was a contact printing technology. In the 1950s, several companies, like Kodak sold desktop reflex copying machines. This technology had numerous problems: it required expensive chemically treated papers, and copies smelled bad, were hard to read, were not durable, and tended to curl up into tubes.Electrostatic Photocopying Machines: Xerography: The first commercially successful machine was introduced in 1950. The first plain paper office copying machine, the Xerox 914, was introduced in early 1960. The Xerox 914 produced 400 copies an hour.


Printer types Dot matrix printer Inkjet Color laser Special types (dye-sublimation, solid ink) Plotter

Cutter 3D printer Imagesetter (RIP)


Dot matrix printer (1970-)A dot matrix printer or impact matrix printer is a type of computer printer with a print head that runs back and forth on the page and prints by impact, striking an ink-soaked cloth ribbon against the paper, much like a traditional typewriter.The technology was invented around 1970 and is still in use.Several manufacturers (Panasonic, Citizen, Oki) implemented color dot-matrix impact printing through a multi-color (CMYK) ribbon, like Apple ImageWriter II (1985).Due to their poor color quality and increased operating expense, color impact models never replaced their monochrome counterparts.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.


Dot matrix printer

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Dot matrix printer

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Dot matrix printer – pros and consAdvantages:

Very cheap operation (no special paper, cheap ribbons): the lowest printing costs per page

Carbon copy (impact technology)Highly durable, reliable: very simple technology Ideal for rare useTractor feed paper

Disadvantages:NoisyRelatively low speed (there are very high speed models for

industrial use, but they are very expensive)Single-sheet paper usually has to be wound in and aligned

by handVery low resolution graphics, with very limited colour

performance


Dot matrix printer – pros and cons 2

Map printing:

B&W thematic maps (SYMAP)


Inkjet printer (1976-)The concept of inkjet printing dates back to the 19th century. Lord Kelvin first patented the continuous inkjet method in 1867, but it took nearly a century for technology to catch up with the idea.

Research and development in inkjet technology had accelerated during the 1960-1970s. In 1976, IBM introduced the Model 6640 continuous inkjet printer which set new standards for print quality. In 1977, Siemens invented thermal or drop-on-demand printing, the method used in most inkjets today. In 1984, HP introduced its first inkjet printer, the HP Thinkjet. A year later, Canon released the Canon BJ-80, the world's first bubble jet printer.In 1994 Epson released the first high-resolution (720 dpi) inkjet printer.1994: this was the first year when more inkjet printers than dot matrix printers were sold in USA. This year 90% of the models were already colour.


Inkjet printesInkjet printers operate by propelling variably-sized droplets of liquid or ink onto almost any sized page. 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.

They were different techniques developed: Canon: bubble jet HP: thermal drop-on-demand Lexmark (1992-) – originally owned by IBM Epson: piezoelectric (after 1993)

Evolution: Only B&W cartridge B&W + one multi colour cartridge (CMY) Separate cartridges (CMYK) Photorealistic printing (6 or more cartridges)


Inkjet printer


Inkjet printers – pros and consAdvantages:

QuietVery high resolutionPhotographic-quality printingRelatively cheap devicesLarge format (A3+) printers are available

Disadvantages:Good quality inks are expensive (microchip trick)The lifetime of inkjet prints is regularly limitedMost of the inks are water-soluble, care must be taken with

inkjet-printed documents to avoid even the smallest drop of water

Special papers are necessary for the best qualityThe ink consumed cleaning them - either during cleaning

invoked by the user, or performed automatically by the printer - can account for a significant proportion of the total ink installed in the machine.


Inkjet printers – pros and cons 2

Map printing:

The most important method for map printing:

Vivid coloursHomogenous fills


Laser printer (1969-)

The laser printer technology was invented at Xerox in 1969 and incorporated into a fully functional networked printer system by about a year later.The first commercial implementation of a laser printer was the IBM model 3800 in 1976, used for high-volume printing of documents such as invoices and mailing labels.

The first laser printer designed for use with an individual computer was released with the Xerox Star 8010 in 1981, but this was very expensive ($16500). After personal computers became more widespread, the first laser printer intended for a mass market was released in 1984 by HP ($3600).Colour laser printers were extremely expensive till the end of the 20th century (QMS, 1993: $12500).


Laser printers

As with most electronic devices, the cost of laser printers has fallen markedly over the years. In 1984, the HP LaserJet sold for $3600, had trouble with even small, low resolution graphics, and weighed 32 kg. Low end monochrome laser printers often sell for less than $75 as of 2010. These printers tend to lack onboard processing and rely on the host computer to generate a raster image, but still will outperform the LaserJet Classic in nearly all situations.


Laser printer


Laser printers – pros and consAdvantages:

FastDurable quality (similar to copy machines)Special paper is not necessary

Disadvantages:Expensive cartridgesCan produce ozonePhotographic quality is not as good as inkjet

printers (not because of the lower resolution)Max. A3 size


Laser printers – pros and cons 2

Map printing:

Very fast proofs, interim prints for checking.Can simulate the offset printing method (Postscript).


Special types (1957-)Since the colour lasers became less and less expensive and the inkjet printers are as fast as the laser printers there is no space on the market for special types of printers.

Dye-sublimation:Most dye-sublimation printers use CMYK colors in that the black dye is eliminated in favour of a clear overcoating.Many consumer and professional dye-sublimation printers are designed and used for producing photographic prints.

Solid ink:The technology was created by Tektronix in 1986.Solid ink technology utilizes solid ink sticks in lieu of the fluid ink or toner powder usually used in printers. After the ink stick is loaded into the printing device, it is melted and used to produce images on paper in a process similar to offset printing.


Special types


Special types – pros and consAdvantages:

The technique is very reliableFor photographs, this technology produces very natural

printsThe prints are dry and ready to handle as soon as they exit

the printer

Disadvantages:The technology is not very flexibleLines are not very sharpExpensive (or very expensive) operationThese printer types are obsolete.


Plotter (1959-)

Pen plotters print by moving a pen across the surface of a piece of paper. This means that plotters are restricted to line art, rather than raster graphics as with other printers.Pen plotters can draw complex line art, including text, but do so very slowly because of the mechanical movement of the pens. Pen plotters are incapable of creating a solid region of color; but can hatch an area by drawing a number of close, regular lines.

Pen plotters have essentially become obsolete, and have been replaced by large-format inkjet printers.


PlotterEarly pen plotters, e.g., the Calcomp 565 of 1959, worked by placing the paper over a roller that moved the paper back and forth for X motion, while the pen moved back and forth on a track for Y motion. The paper was supplied in roll form and had perforations along both edges.Another approach involved attaching ball-point pens to drafting pantographs and driving the machines with motors controlled by the computer. This had the disadvantage of being somewhat slow to move, as well as requiring floor space equal to the size of the paper, but could double as a digitizer. A later change was the addition of an electrically controlled clamp to hold the pens, which allowed them to be changed, and thus create multi-colored output.Hewlett Packard and Tektronix produced small, desktop-sized flatbed plotters in the late 1960s and 1970s.


Plotter


Cutter (cutting plotter)A vinyl cutter is used by professional poster and billboard sign-making businesses to produce brilliant weather-resistant signs, posters, and billboards using self-colored adhesive-backed vinyl film that has a removable paper backing material.Colors available are generally limited only by the collection of vinyl on hand.

Generally the hardware is identical to a traditional plotter except that the ink pen is replaced by a very sharp knife that is used to cut out each shape, and the plotter may have a pressure control to adjust how hard the knife presses down into the vinyl film, allowing designs to be fully or partly cut out.


Cutter (cutting plotter)


3D printers (1986-)3D printing is a unique form of printing that is related to traditional rapid prototyping technology.A three dimensional object is created by layering and connecting successive cross sections of material. 3D printers are generally faster, more affordable and easier to use than other technologies.

A 3D printer, which has nothing to do with paper printers, creates an object by stacking one layer of material — typically plastic or metal — on top of another.The technology has been radically transformed from its origins as a tool used by manufacturers and designers to build prototypes.

Depending on the type of job at hand, a typical 3-D printer can cost from $10,000 to more than $100,000 (2010). Stratasys and 3D Systems are among the industry leaders.


3D printers


Imagesetter (1986-)

An imagesetter is a high resolution output device that can transfer electronic text and graphics directly to film, plates, or photo-sensitive paper. It can be thought of as a very expensive high resolution printer and can come in many different sizes and formats.An imagesetter uses a laser and a dedicated raster image processor (RIP) and is usually PostScript-compatible to create the film used in computer-based preproduction work.The resolution on a typical imagesetter is 1270 or 2540 dpi with a maximum dpi of 4800. In process color work, an imagesetter creates the separated output by "printing" the image four times.


Imagesetter


Computer to plate (1997-)The computer-to-plate (CTP) method is gaining popularity. This method allows a printing company to burn the plates directly from the computer. The advantage, of course, is that no quality is lost in the conversion from computer to film to plate.


PlatesetterA platesetter is a machine which receives a raster image from a RIP and in turn, creates a lithographic plate suitable for use on an offset press.Plates are often hole punched by the platesetter.


Proofs


Proofing 1A proof is a quality control „printing” tool that is used as a means of communicating the overall concept of a project between the production staff and the customer. The type of proof and the quantity of proofs that are made may vary with each job. If the proofing process is completed accurately, any problems or errors can be caught before a job is offset printed.

There is a wide variety of proofing systems and different technologies to choose from. It is important to understand the different processes and the advantages and disadvantages of each. When choosing a proofing method, consider the following factors:cost,repeatability,accuracy, andthe workflow used to produce the final image.


Proofing 2The color gamut of different proofing technologies and printing processes usually do not match. Part of the color gamut that can be achieved by the proofing system is not possible with the printing process. Trying to match the proof colors with print colors is where a color management system can help.

Using a color management system and the application of ICC compliant color profiles will help to produce quality proofs that will ensure the same color on press. In order for color management to work, rigorous quality control measures must be utilized, kept current, and employed often.

In map production process this factor of proofing is regularly not so relevant.


Proof typesTraditional proofing (offset proof print)Soft proofHard proof:

Photo-mechanicalBlue lineComposite Overlay ProofComposite Integral Proofs

Precoated SubtractiveAdditive

Digital


Traditional offset proofingThis was the only proof method of the non-digital era. It was a simple offset printing machine (single-color sheetfed offset printing machine).A press proof is used to verify images, tone values, colors, and imposition.


Soft proofingSoft proofing is simply a mechanism that allows us to view on our computer monitor what our print will look like when it is on paper (WYSIWYG: What You See Is What You Get).That paper and ink combination has been defined by the profile that we or someone else has made for our printer / paper and ink combination. When a printer profile is made the color of the paper is one of the factors that is figured into the profile.

So, if we were able to view our image through the printer profile, we would be able to see how that particular combination of ink and paper would reproduce it, taking into account the gamut as well as other characteristics of the inks used.


Analog proofs in generalAn analog proof requires that film negatives or positives be made (on a traditional way or imagesetting) in order to produce the colour proof. Analog proofs can be categorized as either an „analog position proof” or an „analog contract proof”.

An analog position proof provides an overall concept of the color scheme for the project, as well as the design format. Because the colors that are used to make the proof do not coincide with the colors utilized with the printing device, it is never used as a guide to match the color with the final printed piece.

The analog contract proof is used as the final version approved by the customer, in which the colors of the final proof are expected to match. The analog process utilizes film negative color separations of the primary subtractive color components (CMYK). The separations can also be used to create the printing plates.


Analog proofs: Blue lineThe traditional standard in the printing industry has been the DuPont Dylux monochrome proof, also called a blue line.A blue line is a photographic contact print of plate-ready negatives, which make it a composite proof. A blue line proof is relatively inexpensive and is produced using a photosensitive paper with the same specifications of the jobs signature that turns blue when exposed to ultraviolet light. There is no processing involved. It can be folded, trimmed and stitched to approximate the finished job. The proof is bluish in color, and the image fades with time.

Bluelines are used to check:•Text and headline placement•Halftone cropping size•Placement and size of rules, reverses and tints•Page sequence•Crossovers and backup•Scores, perforations and drills•Trims, fonts and binding


Analog proofs: Composite overlay proofOne of the most well-known composite overlay proofs is Colour Key developed by Kodak.Each layer is a separate color overlaying each other. The collared layers usually represent the color separations (cyan, magenta, yellow, and black) and/or any spot colors.Most systems use a vacuum frame to hold the film layers or flats in contact with the light-sensitive coated sheet. The light source exposes the emulsion and the product is then processed. This process occurs for each color layer. The composite overlay proof can be useful for checking color breaks, trapping, text, and layout, but it is not as good as other types of proofs for matching color at the press.


Analog proofs: Composite integral proofPrecoated SubtractiveAn example of a precoated subtractive proof is MatchPrint (Kodak, 3M). A negative for each color is placed on a laminated color sheet receiver stock, exposed to ultraviolet light, and then processed. A precoated subtractive proof can take about 30 minutes to produce.Consistent densities, dot gain, and color are the main advantages of this type of proof.


Analog proofs: Composite integral proofAdditiveAn example of an additive proof is Cromalin (DuPont).An additive proof is made by hand-mixing powdered toners for each color. The toners are available in color kits that can be used to create many pantone colors. This process is repeated for each color and can be made on any stock. An additive proof takes about 30 minutes to produce.

The advantages of an additive proof are:there is no limit on the number of colors that can be used, we have the ability to mix our own colors,We may apply any density that we desire.

The main disadvantage is the inability of the colors to be consistent. The inconsistency is due to the hand mixing of the colors, which may cause a slight variance in the colors each time they are mixed.


Digital proofsDigital proofs are made directly from the computer authored digital file without creating a set of films. The digital file is the same file that will be used to create the printing plates. The quality of digital proofs has improved to a level that is acceptable for use as a contract proof, which is necessary as the industry moves to a filmless workflow.

When using digital systems for proofing, be aware that the device(s) need to be color calibrated often to maintain color accuracy, and color bars should be used on every proof.

A digital proofing process involves printing each of the subtractive primary color components of the image (cyan, magenta, yellow), and black on one pass through the output device to create the full color digital proof.


Digital proofs Dots or no dots - many of the technologies cannot

produce proofs with halftone dots. The systems that are able to produce proofs with halftone dots, may not produce dots that are of the exact size and shape, or at the same screen angle as those imaged on the printing plate. With the differences in dot size and shape and screen angles, it would be difficult to predict problems such as moiré patterns.

Another factor is the ability to see the effects of overprinting.

The key advantages of digital proofs over analog proofs are that the costs can be less than half that of an analog color proof and they are produced in much less time.


Digital proofs: digital sublimation

A digital sublimation proof is the closest of all digital proofers to the analog proofing method. The digital sublimation proof system requires little maintenance and is reasonably consistent.There are two different types of sublimation proofers: dye-sublimation and laser sublimation.Dye Sublimation Proofers were the first of the sublimation systems on the market. The proofs are called Dye Subs.

The disadvantages are: the dye colors on the proof will fade with time and may not match the color at the press; the proofs must be viewed under proper lighting conditions; the process has limited resolution and produces a continuous tone effect.

Laser Sublimation Proofers are the first of the dot oriented digital proofers. This system is much more expensive and is slower than the dye sub system, but the quality has been considered equal to the analog proofing system.


Digital proofs: thermal waxThermal wax printers work in the same way as the dye-sublimation printers except the printer ribbon is coated with colored wax instead of using dyes. As the thermal head heats up, the wax fuses to the paper. The thermal wax printer also prints only one process color at a time so the paper must be fed into the printer four separate times to produce the full color image.Thermal wax printers produce strong, vivid colors, and they are much faster, but they are also more expensive than inkjet printers.


Digital proofs: inkjetSince the proofing substrate is much whiter and glossier than most papers, the inkjet proofs usually appear better than the printed piece.To compensate for the paper difference, some inkjet systems allow a simulation of the paper to be printed on the proof by printing the paper color with the rest of the document.The inkjet printers require high-quality coated or glossy paper for the production of photorealistic output. The surface must allow the ink to dry instantly during printing to avoid smearing and ink spreading.

The problems associated with inkjet printers are:The ink has a tendency to smudge immediately after printing.The proofs are not waterproof.They are expensive to maintain.


Digital proofs: color laserColor laser copiers, interfaced with fast and powerful RIPs, are now being used by service bureaus, quick printers, and design shops as a way of producing quick proofs or short-run, variable-data digital color printing.


László ZENTAIEötvös Loránd UniversityDepartment of Cartography and GeoinformaticsPázmány Péter sétány 1/A1117 Budapest, HUNGARYTel. + 36 1 3722975Fax + 36 1 3722951Email: [email protected] site: http://lazarus.elte.hu

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