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New Advances in Inkjet CtP

Conventional inkjet systems are furthering computer-to-plate solutions

For the past decade, commercial printing plate manufacturers and inkjet imaging specialists have been working on an effective system for imaging commercial printing plates through some type of inkjet printing device. A few polyester devices with fairly limited quality capabilities have been introduced over the years, but their limitations have resulted in these machines barely making a dent in the overall computer-to-plate market.

Inkjet printing, meanwhile, has progressed by leaps and bounds in the past decade. The increasing quality of screening, and decreasing size of dots have been augmented by much higher speed and much more durable printheads.

Now, the same advances in printer technology that have been making your life easier are allowing computer-to-plate (CtP) technology to be accomplished through conventional inkjet systems. Both of the new products I discuss here are built on conventional off-the-shelf wide-format printers. They also use customized versions of off-the-shelf RIPs.


Print Imaging Sciences, Inc. of Nashua, NH, now named JetPlate (www.jetplate. com), won a GATF technology award in July 2002 with its JetPlate system, which this magazine reported on at that time.

JetPlate is an affordable, desktop metal CtP system for small offset presses, based on an inexpensive B3-format inkjet printer. While other CtP systems use costly lasers, this system's plates are imaged with innovative "liquid light" ink, which reacts with the photosensitive emulsion. "This inexpensive system, with inexpensive consumables, ties into other vendors' systems and brings computer-to-plate technology to the majority of our industry"?the small or low-end printers," a GATF judge explained when making the award.

At Drupa, the newly minted company displayed its latest releases and its new corporate name, but the big news was the interest being stimulated by the fact that these machines can image highquality conventional metal commercial printing plates with up to 175 lpi-equivalent resolution. This is being done with some modifications to an off-the-shelf inkjet printer using what the company calls "liquid light," a liquid applied using a standard ink cartridge. This is a photosensitive chemical that must be processed through a standard plate processor. The company includes a Harlequin RIP in its package, which sells as low as $30,000 for a 2-up (JetPlate 4000) version; a 4-up version (JetPlate 7600) is also available.

Glunz & Jensen iCtP

But Glunz & Jensen (www.glunzjensen. com), well-known for its plate and film processors for the commercial print industry, has taken inkjet CtP a step further with its iCtP system. This is a chemistry- free solution, using only a relatively cool (110"?) curing process and the only "chemical" used is a finishing gum. The imaging is also done on non-sensitized plate material"?a considerably lessexpensive solution. Since these units will sell for about $35,000 (published reports immediately after Drupa incorrectly stated a $25,000 figure), the total cost per plate produced is dramatically less than conventional CtP.

The PlateWriter 4200 platesetter prototype units used an FM screening algorithm generated by a Harlequin-based Xitron RIP, which the company reports is giving them excellent quality. The FM screening in the prototype is capable of emulating 175 line conventional screening. Hank Clifford, G&J's US VP for sales and marketing, says the company also is actively working on AM screening for the device and has set that as a high priority.

Breakthrough technology

The chief problem that has delayed the release of a high-quality metal imaging device through inkjet technologies has been in the screening process itself. Recent developments, however, have allowed manufacturers to develop much greater control of dot size and shape to avoid coarse screening and banding and stepping issues. While printing on paper has been more forgiving, and manufacturers have effectively mitigated most of those issues, imaging on metal had its own set of issues that have been much more difficult to solve. Early entries to utilize CtP for plate marking have been done with polyester plates that are largely used in lower-quality commercial print.

To move to a commercial quality level of imaging meant hitting the 175 lpi mark, and that was a tough proposition. Both JetPlate and Glunz & Jensen say they have been able to hit that benchmark. The samples printed at Drupa seem to indicate to those who have seen them that they have indeed made the breakthrough that has escaped them for so long. This writer did see a sample of a G&J piece printed at Drupa, which gave every appearance of having come off a conventional laser CtP device. Both companies also say the issues of registration and repeatability have successfully been dealt with.

Lowering the barriers

What is happening industry-wide is a further blurring of the line between "copyshops," commercial printers, and wide-format print providers. Commercial printers, for instance, are buying digital presses such as the HP Indigo and the Xerox 6060, while copy shops are buying "direct imaging" (DI) solutions like the KPG and Ryobi DI presses.

Certainly, wide-format operations would look askance at buying a $100,000 platesetter with a totally new front-end computer system to step into the realm of commercial print. But now the bar has dropped a couple of notches"?the price of admission has been cut by two-thirds. And the technology itself is no longer foreign: it's something the wide-format print provider deals with every day.

Will these new CtP offerings entice some companies who specialize in wide format and similar graphics to cross over the line? The device manufacturers are orienting their marketing to small commercial printers and larger copy shops, but wide-format printers may not want to wait and watch their competition exploit a promising new technology that they have a great deal of experience with. These new products might well be worth a look, if only to see where inkjet technology is headed.

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