CONVERTECH & e-Print January / February 20134

DLC Coating 20 Cylinders SimultaneouslyEnvironmental Impact Reducing FX-eco Cylinders

In Japan, Gravure printing technology is used for everything from printing flexible packaging to patterning optical films and elec-

trodes, and more recently for producing components incorporated into smartphones and tablet PCs. In many cases, however, the fact that gravure printing is used for such electronic components is subject to confidentiality agreements, so rarely comes out to the public. THINK LABORATORY CO., LTD., the manufacturer of a fully automated laser cylinder making line for cylinders meeting this wide range of applications, will be releasing the test results of its diamond-like carbon (DLC) dry coating replacement for chrome plating at Convertech JAPAN 2013. In addition, they will also be presenting the test data on VOC emissions and ink usage re-duction achieved by combining the FX-eco cylinder produced on their latest cylinder making line “New FX” with high solid gravure ink; samples of film printed with rice ink using rice bran oil as the main resin; samples printed with their Plating-less, Etching/En-graving-less, DLC/Dry Process that eliminates the need for copper and chrome plating completely, intended for release in 2014; and a demonstration of their dot code technology using Apple’s iPhone and iPad.

Large Cylinder Dry Coating ChamberIn general, gravure cylinders are plated in chrome as a protec-

tive surface for the cells formed into the copper plated sur-

face. The handling of chrome plating requires strict control,*1

however, so there has been a strong demand in the gravure

cylinder making industry for a hard replacement material. In

response, THINK LABORATORY is proposing the use of DLC.

The centerpiece of this approach is their massive DLC

dry coating vacuum chamber which they installed in their

#2 Plant this past October. The DLC film coating chamber

can hold large shafted cylinders of up to 1,000 mm in diam-

eter, 3,500 mm in length, and 3 tons in weight, which is the

size of THINK LABORATORY’s patterning cylinders used by

Samsung of Korea for the address electrodes of their 50 inch

plasma display panels (PDP).

With DLC coating, however, the problem is the long coat-

ing time, which THINK LABORATORY has solved by using

simultaneous multiple cylinder coating. By changing out the

mounting unit, the chamber can simultaneously hold 20 hol-

low flexible package printing cylinders of 1,100 mm in length. A

planetary gear rotates the center axle while rotating the individ-

ual cylinders so that the surfaces are uniformly coated in DLC.

When the mount is fully loaded with 20 flexible package print-

ing cylinders coated in the black DLC, it has a powerful ap-

pearance. As of the end of October 2012, they have been able

to form the DLC coating in the new chamber, but are currently

working on increasing the precision of the system via obser-

vations of the coating thickness uniformity of large rollers. In

tests using 20 cylinders held over two days in December they

confirmed that simultaneous DLC coating was possible.

PED Cylinder Coating TestsThis chamber is not simply used to coat a replacement material

for chrome plating. With conventional printing cylinders, cells

are typically etched into the copper plating via electro-engraving

20 DLC Coated Flexible Package Cylinders

DLC Coating a Massive 3 Ton Cylinder

*1 The hexavalent chromium used in the plating bath for chrome plat-

ing is subject to strict regulations, as with lead and cadmium, given

its high toxicity as a carcinogen and ground water pollutant. The

EU Restriction of Hazardous Substances prohibits the inclusion of

hexavalent chromium in electrical and electronic components and

recommends replacement with chromate processing using less

toxic trivalent chromium. The hard chrome plating formed via plat-

ing itself is chromium metal, so is not subject to regulation.

January / February 2013 CONVERTECH & e-Print 5

PrintingEngraved Compared Items FX-eco

40 µm Cell Depth 10 µm

80-100 µmCopper Plating

Thickness40 µm

6 µmChrome Plating

Thickness4 µm

— Ink Reduction 15-30%

175 Lines # of Lines 250 Lines

FX-eco and Engraved Cylinder Comparison

or corrosion and finally coated in chrome plating. In contrast to

the conventional process, PED, which THINK LABORATORY

introduced to the world at drupa 2012, forms micrometer order

patterns directly onto the surface of the cylinder via DLC plasma

coating. In short, this ambitious technology directly forms the

walls that divide the individual cells. The vacuum chamber for

dry coating is also being used for testing DLC coating of these

PED cylinders. While they were only able to display a PED cylin-

der at drupa, they displayed actual packaging samples printed

with a PED cylinder at TOKYO PACK 2012 this past October.

THINK LABORATORY also has other samples printed using

PED cylinders that provide a glimpse at the immediate future of

gravure printing technology development.

High-solid Ink for FX-eco CylindersAt 10 μm, the cell depths of the CMY cylinders made with

New FX are even shallower than the 14 μm cell depths made

using THINK LABORATORY’s conventional cylinder making

line. With 10 μm cell depths, the density of the K cylinder is

insufficient, so these cylinders continue to use a 14 μm depth.

Shallower cells reduce the amount of ink and solvents

used, which as a result reduces the amount of volatile organic

compounds (VOC) emitted. This relationship has already

been proven via past testing by YASHIO CHEMICAL CO.,

LTD., DAISAN FILMS CONVERTING CO., LTD., and CHIYODA

GRAVURE CORPORATION. Specifically, when using high-

solid gravure ink it is possible to reduce ink usage by 30%

compared to engraved cylinders and 15% compared to stan-

dard laser cylinders. In addition, data show a 15% reduction

compared to engraved cylinders even when using standard

solvent inks.

By reducing cell depths, it is also possible to use thinner

copper and chrome plating. For example, standard copper

plating is 80 μm and chrome plating 6 μm, but these can be

reduced to 40 μm and 4 μm, respectively. A comparison with

engraved cylinders is shown in the table above. As a result,

the thinner plating also reduces the required electricity and

materials for plating.

Until recently, the only high-solid gravure ink, another

eco-friendly measure, available was SAKATA INX CORPORA-

TION’s Belle Color-HS, but this past fall DIC CORPORATION

developed FINART, expanding the range of choices.

28% VOC and 25% Ink ReductionThis past December, four different cylinder/ink combinations

were tested at CHIYODA GRAVURE’s Itako plant. The tests

measured the VOC concentration after 4,800 m of CMYK+W

5-color reverse printing at 200 m/min of the same image on

OPP film supplied by FUTAMURA CHEMICAL CO., LTD. The

four combinations were: FX-eco cylinder (depth 10 μm) and

Belle Color HS; FX-eco cylinder and FINART; standard laser

cylinder (depth 14 μm) and solvent gravure ink Belle Color

(SAKATA INX); and engraved cylinder (175 lines, depth 40 μm)

and Belle Color. FX-eco is a THINK LABORATORY cylinder

that can be used with both water-based and solvent inks. “FX”

is the name of their laser exposure unit and “eco” refers to the

concept that the cylinder reduces ink and solvent usage, sup-

presses VOC and CO2 emissions, and cuts down on power

Printing Length (m)

Printing Time (min)

VOC

(ppm

C)

0 1,000 2,000 3,000 4,000 5,000

0 5 10 15 20 25

1,600

1,400

1,200

1,000

800

600

400

200

0

Laser 10 µmLaser 14 µmEngraved

“SU8020” Ultra-high Resolution FE-SEM, ×800,000 magnification (Hitachi High-Technologies Corporation), Installed at THINK LABORATORY’s Next Generation Gravure R&D Laboratory. The SU8020 Is Used to Observe Cylinder Cell Shapes and Ink Coating of Proofing Prints

VOC Emissions Concentration Comparison of FX-eco, Standard Laser, and Engraved Cylinders

CONVERTECH & e-Print January / February 20136

Printingconsumpt ion. Compar i -

sons of continuous printing

showed that both the FX-eco

and standard laser cylinders

produced VOC concentra-

tions that were 28% lower

than those produced by

the engraved cylinders. The

white cylinder in all combina-

tions except the engraved

cylinder combination used

high-solid ink.

Acco rd i ng to Ta tsuo

Shigeta, president of THINK

LABORATORY, the volume ratio of the cell volumes of the cyl-

inders is about the same, or sightly less for the laser cylinders.

As such, this large difference in VOC between the engraved

cylinder and laser cylinder shows that the FX-eco and laser

cylinders apply the pigment without loss. Currently, they are

analyzing the mechanism behind these results.

One possible reason why the FX-eco and laser cylinders

showed almost no difference in VOC emissions, however, is

because the printing machine used for the tests recirculates

30% of the exhaust to improve drying efficiency. Even so, the

difference with the engraved cylinder is clear. Regarding ink

reduction ratios, they are in the process of calculating this

from the solvent ratio, medium reduction ratio analysis, and

pigment weight comparison. While the results differ by color,

Mr. Shigeta says that estimates show the possibility of a 25%

ink volume reduction. He hopes to be able to release the de-

tails of the data from the test samples soon.

Mr. Shigeta goes on to say that given average gravure

printed lot sizes of 4,000 m in Japan, this round of testing

shows that printing using FX-eco cylinders should result in

a VOC emissions concentration of about 1,100 ppmC. If the

VOC emissions concentration can be further reduced by 30%

from this level, the printing machines would be exempt from

the regulations of the Revised Air Pollution Control Act.*2 This

is something they would like to continue working towards.

Rice Bran Surface Printing InkOne other piece of news is their printing of samples using

PIXESS RICE INK, a surface gravure printing ink containing

rice bran oil (100% domestic content) recently developed by

T&K TOKA Corporation for treated polyethylene film used in

rice bags, for example.

One Operator, Two LinesOn the second floor of THINK LABORATORY, the #1 New FX,

installed in the fall of 2010, is operated by a single operator

during the day but operates automatically during the night. In

October 2011, they installed a second improved version of the

New FX next to the #1 line; the two lines can be operated si-

multaneously by a single operator to make eight cylinders per

hour. They have confirmed that the machines are stable over

the long term and have also compared the machines using

different chemicals and materials.

Exporting Around the WorldIn January of 2013 one New FX line was exported from Japan

to an electronics manufacturer and in May another line will be

delivered to HANDOO PACKAGE CO., LTD., the top cylinder

maker in Korea. In January, HANDOO PACKAGE will also re-

ceive an “FX-80” line, the predecessor to New FX, but this FX-

Tatsuo Shigeta, President of THINK LABORATORY

#2 New FX Line in Operation at THINK LABORATORY

HANDOO PACKAGE’s New Plant Will Hold an FX-80 and New FX Lines

*2 The Revised Air Pollution Control Act established in 2004

sets the goal of reducing VOC emissions by 30% (compared

to 2000) by 2010. Gravure printing facilities with an exhaust

capacity of 27,000 m3/h or higher and a VOC emissions con-

centration of 700 ppmC or higher are subject to regulation.

January / February 2013 CONVERTECH & e-Print 7

Printing80 will use the same laser exposure unit as the New FX, an

infrared semiconductor 208 multi-beam laser unit with a 6,400

dpi resolution.

Mr. Shigeta says that HANDOO PACKAGE already has

one THINK LABORATORY stand-alone laser exposure unit,

so come May they will have installed three such laser units.

One floor of HANDOO PACKAGE’s new plant will have an

FX-80 and New FX side by side, so dual operation by a

single operator will begin in Korea, too. In addition, HANDOO

PACKAGE made 14 μm cell depth cylinders using a THINK

LABORATORY data file and tested inks by three Korean ink

manufacturers. While the results were only proofing prints, the

samples were equivalent in quality to those printed by THINK

LABORATORY, giving confidence to THINK LABORATORY

that the experiments they have made in Japan will be repro-

ducible in Korea.

With these deliveries, at the beginning of 2013 THINK

LABORATORY will have delivered 10 New FX lines. In 2013,

there will be more than 90 multi-beam laser exposure units

able to make FX-eco cylinders in operation, including lines

pre-installed with the unit and lines for which the older argon

laser has been replaced.

Reading Dot Codes with the iPhone The New FX can also make the black cylinder used for print-

ing dot codes. By printing dot codes into the images or char-

acters and reading the invisible codes with a dedicated pen

scanner, the user is linked to a server URL for the dot code.

This system allows for data that cannot be printed to be dis-

played as a static or moving image. Until now, this system

required a dedicated scanner, but by attaching a less expen-

sive plastic lens to the camera of an iPhone or iPad, it is now

possible to read the dot codes with these devices. THINK

LABORATORY demonstrated how the new approach worked.

THINK LABORATORY CO., LTD. www.think-lab.com

Dot Code Displayed on an iPhone During Reading

www.think-lab.com www.think-lab.com