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May 1, 2001 12:00 AM


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SINCE INK AND WATER DON'T HAVE TO BE BALANCED, CORRECT COLOR DENSITY IS ACHIEVED IN SIGNIFICANTLY FEWER SHEETS

This past year, Sun Chemical Corp. (Northlake, IL) and Flint Ink (Ann Arbor, MI) announced what some observers consider the most significant conventional pressroom advancement in years: single-fluid inks.

“Single-fluid inks eliminate water and dampening systems, which minimizes dot gain while eliminating the ink/water balance struggle,” explains Bill Lamparter, president of PrintCom Consulting (Charlotte, NC), a graphic arts consultancy. “Since wastewater is eliminated, there are environmental advantages, too.”

The consultant further notes that, when combined with keyless fountains (such as that on the 74 Karat digital offset press), these new inks “offer an interesting potential for simplification of press design, cost reductions and printed product improvement.”

RIT professor Frank Romano predicts that single-fluid inks will enable conventional offset to be competitive with short-run digital printing — “at least while prices for digital consumables remain so high.”

Also, eliminating the dampener could enable printers to install digital imaging or on-demand equipment in the vacated space.

SAME NAME, NEW APPROACH

While the concept of single-fluid inks can be traced back to the 1970s, the modern versions are similar in name only. “Technology marches on,” says Les Watkins, Flint Ink's director of new technology. “Plates have changed as have the chemistry of the inks. And press controls now permit a degree of control that was previously impossible.”

Watkins also notes that the new generation of inks is waterless. By contrast, the single-fluid inks developed for printing newspapers involved injecting ink, premixed with water, into the press.

At Drupa, Flint Ink showed its Single-Fluid Ink (SFI) for four-color process sheetfed applications and a book black for heatset web applications. It is also being tested on four-color process heatset web presses. The inks were demonstrated running with Presstek's Anthem thermal plate, but Flint reports its SFI can run on any press — no special plates, temperature control or press adaptations are required.

Watkins says printers and press manufacturers have expressed a strong interest in SFI — at one point Flint was getting 20 to 30 inquiries a day. He attributes some of this interest to the waste reduction made possible by SFI. Since ink and water don't have to be balanced, correct color density is achieved in significantly fewer sheets, and color consistency and accuracy are maintained throughout the run.

SFI also reportedly has good print clarity, particularly in shadow and mid-tone areas. Dots are said to be visible into the 95 percent screen range, compared to the 80 percent to 85 percent range for conventional offset printing.

While SFI has generated much early excitement, the real test will come “in the hurly-burly working environment of the printing plant,” according to Watkins. “Will it let you run the press faster? We don't know yet.”

A total of 10 beta sites are planned. A book printer, Port City Press (Baltimore, MD), was the first beta site, but Flint now has sheetfed and heatset web SFI beta sites as well.

“We're in early to middle beta testing,” says Watkins. “Our target for release, sheetfed-wise, is the end of the year.”

ELIMINATING SOLVENT-BASED CLEANING

Sun Chemical announced InstantDry W2 and DriLith W2. Both are waterless, water-washable inks that eliminate the need for solvent-based press cleaning. InstantDry W2 is for Heidelberg's Quickmaster DI press, while DriLith W2 is for large-format sheetfed presses operating waterless.

Both inks require the use of waterless printing plates and on-press temperature control to maintain optimum ink viscosity. Sun has indicated, however, that tests done under increasing temperatures led to a decrease in toning, suggesting that DriLith W2 inks might be beneficial when printing conventional waterless without temperature control. The inks are now commercially available. (See “Water-washable ink steps up to the plate,” p. 42.)

Single-fluid inks could eliminate the ink-and-water balance issues said to account for 70 percent to 80 percent of printing problems. Will this goal be realized, and at what cost? Will the new inks impose performance challenges of their own? Only time — and more testing — will tell.