Status Report: Single-Fluid Inks

by Robert M. Di Santi

As operational costs lead production people to examine the processes they employ, many are eyeing the slow evolution of single-fluid inks.

The typical printing process uses a mixture of two liquids: ink and fountain solution (concentrate plus water). In the 1970s, Journal/Sentinel Inc. in Milwaukee pioneered single-fluid printing by going beyond their di-litho system, which mixed ink and water on a roller before it arrived at the plate, to feed a pre-mixed solution directly to the press.

The Journal/Sentinel's primary goal was to save money. However, they, like other newspaper people, knew that single-fluid inks would also have other potential advantages:

• Simplification of the press: The Journal could use its existing letterpress equipment. For single-fluid inks, the dampening system would no longer be needed.
• Time savings: Using single-fluid inks, the pressmen would not have to constantly adjust the ink/water balance during a press run.
• Cost savings: By automating ink/water adjustments, the paper would reduce make-ready waste, with salable copies coming off the press sooner.

From 1979 through 1988, the Milwaukee company used its prototype single-fluid ink system to print its newspapers. It was thought that by eliminating a variable (the fountain solution) from the process, cost would be reduced. But in, 1979, today's spray-bar dampener, which eliminates much of the waste associated with the traditional fluid mix, did not exist. Had the contemporary spray dampener been available in 1979, says Production Manager Ray Stoiber of Journal/Sentinel, the company would not have tried single-fluid lithography during that year.

The reasons? The Journal/Sentinel found disadvantages to their single-fluid method, some of which are still not resolved:

• A single mixture of ink and water cannot meet the ink demands of all the pages in a paper. Ink/water balance is also hard to stabilize during the life cycle of a press run. The press temperature changes over the course of the run, and with the excess fountain solution no longer carrying heat away, the temperature would need to be controlled by other means.
• Removing control of the ink/water balance during the printing process means that control of the entire process must be better than is generally the case.
• Constant, arduous monitoring by press operators was required. Today, that monitoring would be carried out automatically by machinery-requiring more machinery, not less as compared to current technology.

In the newspaper industry, change generally comes slowly, and radically new technologies are viewed with suspicion until they are proven in "the real world." Given its potential economic benefits, however, vendors among the press, plate and ink manufacturers continue to explore single-fluid ink, and customer demand will be a driving force to bring it to fruition. Future concepts including positive-feed keyless presses and continued development of anilox inking systems could help bring single-fluid lithography to the forefront.

At present, single-fluid technology remains in the developmental phase. Says Robert Throckmorton. director of corporate service of The Ink Company in Waldorf, Md., "I don't see a mass movement toward it at this point in time." He adds that there is "a lot of interest-with a wait-and-see approach."

TechNews Volume 1, Number 1: January/February 1995

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