Independent industry researcher Image Test Labs (ITL) says it has achieved “a historic first in the printing industry” by configuring Screen’s flagship inkjet press, the Truepress Jet520HD, to deliver the image reproduction quality of a commercial sheetfed offset press over a production run of three miles (4.8km) of paper.

image test labs
 With the results (l-r): Felix Bermudez, Sr. Sheet-Fed Press Operator, Cohber, Rochester, NY; Dr. Peter Crean, Dr. Eric Zeise, Dr. Peter Dundas, and Henry Freedman - all of Image Test Labs.

ITL, a division of US-based Technology Watch, printed a complex test image on each press side-by-side on the same sheet of paper, demonstrating that the output of the Screen 520 HD SC inkjet web press with SC inks is suitable for commercial colour work that requires offset sheetfed quality.

“It is now possible for a production inkjet web printing press to behave like a sheetfed offset printing press,” said ITL’s Henry B. Freedman. “For the first time, regularly supplied off-the-shelf offset paper has been printed by an inkjet web press without requiring any special coatings, resulting in output image quality that matches or exceeds offset quality. Designers can now get much more of what they want from a digitally printed product, opening up a vast volume of work that can be run on an inkjet web press.”

While the world is focused on digital, the vast majority of commercially produced printing is still done by offset lithography — perhaps over 90% globally, said ITL. “In a single month a single offset press typically can exceed the entire volume that most digital presses produce in their lifetimes. As digital print continues to gain market share, inkjet web press technology has still not been able to print real ink on conventional offset paper at production speeds at offset quality and volumes — until now.”

How the Test Was Constructed

ITL established three requirements that the inkjet web press must meet.

First, the press needed to print directly onto off-the-shelf, Verso Sterling Ultra Gloss offset coated roll stock, with excellent adhesion — no smudging or smearing.

Second, the output characteristics had to match offset quality: ink colour gamut, colour reproduction characteristics, appearance of the ink when dried, etc - and with a uniform consistency over the entire three-mile length of the press run.

Third, the inkjet web press had to include high-quality digital front end (DFE) electronics with the requisite range of control in order to set up and maintain press and image quality.

ITL’s research and testing determined that at this time only one inkjet web press has these capabilities: the Screen 520 HD SC. The Screen SC polymer ink used in the test proved to be capable of printing directly on plain, lower-cost conventional offset papers.

tpj 520hd main
  Truepress Jet520HD High-Definition Inkjet Web Press

“We noticed the offset match possibility when we measured the press output as part of the normal testing services we provide to commercial printing firms,” said Freedman. “We have shied away from trying such a match until now. The fact that we can image directly to conventional offset web paper, with no precoating, and run the same paper on both the offset and inkjet web presses, combined with the very high colour image quality of the Screen 520 HD SC, made us confident that the Screen press could stand on an even footing with offset printers. The SC ink resistance to abrasion and rub-off was so great that our independent testing facility did not believe that the samples they tested were inkjet.”

Screen says: “What sets the Truepress Jet520HD apart is its unique printhead technology. The press is able to place 2-picoliter droplets — the world’s smallest level — exactly where the dots are required on paper as it moves through a high-speed transfer system. Combined with the maximum true resolution of 1,200 dpi, the Truepress Jet520HD clearly images detail smaller than 0.10 of a point. The result is a sharp, eye-catching finish with no ink spread or jaggies."

Screen GP Australia says it will have the test result samples available at PrintEx19 in Sydney.



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