The Secret Life of Ink

Thomas Gray, president and CEO of INKnet Systems Inc./Link-Techinc, Waukesha, Wisc., has been studying ink’s performance and conveyance for more than 18 years. Gray describes himself as an “ink mechanic” and, since founding his company in 1990, he has worked with some of the largest printing companies in the United States to develop instruments, products and systems to help them get ink on paper efficiently, with minimal waste, consistent color, and true measurement. His approach has been to closely examine the mechanics of his customers’ ink delivery systems from the tote to the fountain to find better ways of getting the job done. And after almost two decades serving the printing industry, Gray concluded, “Most printers are probably using excessive amounts of ink and they don’t know it.”

Worse, given their often inadequate ink distribution measurement technology, printers can easily miscalculate the amount of ink a job requires or actually consumes, especially work run on high-speed heatset web offset presses. They end by losing money on jobs that should be profitable, or losing customers when the final tally of ink comes in higher than the estimated costs. “Then they ask, where did the extra ink go?” Gray said. He has several answers to this question.

Measure and Record

First, Gray suggests that printers carefully and accurately meter ink usage. Citing the typical case of one customer who was feeding ink to three presses from a single pumping system, he noted that this set-up, though economical, makes it impossible to track where the ink is going. “Meters won’t end ink consumption,” he said, “but they do allow for plotting performance and gaining knowledge.”

Second, Gray noted that with the introduction of high-speed web presses, printers are pumping ink at greater distances and higher pressures, which raises the temperature of the ink. “With heat, ink viscosity gets closer to oil than to peanut butter,” he said. “Heat also makes the paper fibers open up, making it more absorptive. The press operator will notice that the ink is losing density, and he’ll correct that by adding more ink.” Replenishing the ink supply with a new barrel or tote of cold ink only disguises the problem.

“Printers doing mega-runs assume that ink consumption is stable over a million-piece job, but when it’s done, they’ll notice an increase in ink consumption. Most of the time, they can’t figure it out, and they can’t really identify the source of the problem,” he said.

Based on data collected from the LPD meter design, Gray believes printers doing high volume work miscalculate their ink costs by about 30 percent. They don’t and can’t charge customers for this part of the job and simply absorb the expense. He’s working on establishing Print Test Platforms, similar to benchmarks, based on accurately metered ink usage for different color inks and brands of presses. These tests, he said, will help clear up the “production fog” that printers experience now in determining ink usage.

Contamination

Ink manufacturers have changed their ink formulations over recent years to meet changing regulations and market demand, and they’ve also sought out new sources for raw materials. These raw materials can vary in quality and purity, affecting ink chemistry. Commonly used yellow pigment from China is sold to manufacturers only in slurry form, not as a dry powder. Gray suspects that the chemical composition of the ink can crystallize in a runaway, overheated ink pump, damaging the ink pump and the ink itself. “Ink is abrasive,” he said. “Its abrasive nature and potential contaminates can be minimized by effective press-side filtration.”

He also noted that many ink pumps used in the print industry were designed for other products such as grease, paints and oils. Leaking pumps in print shops are common and often tolerated, but, Gray said, “A leaky pump means it’s damaged and not working properly. It also indicates that the internal broken parts are getting mixed in with the ink. A leaky pump can drip about 20 lbs. of ink per year, and there are typically four pumps on a press.”

Any contamination in the ink tends to be self-sustaining, and also contaminates new batches of ink. Even introducing air into the distribution system can be detrimental. “Up until now air has not been a negative, but now air is being metered as ink,” he said. “Air can make ink move bi-directionally in the meter. It can act like a piston and push ink backward through the meter. This is called ‘meter rocking’ and it can add thousands of pounds of ink to the count. The new generation of inking systems cannot tolerate air in the ink at all.”

Quality filtering systems can solve most of these problems and save some of the expense of press maintenance and repair. Gray noted one client who saved about $40,000 over a three-year period for each of 80 presses. Another client, the United States Bureau of Engraving and Printing, improved productivity by 20 percent. “They had to stop and clean each press fountain and doctor blade every four hours, but with filters they could run an eight-hour shift, change the filters and run another eight-hour shift,” Gray said. “And, apart from reducing ink contaminants, ink filters also tend to homogenize the ink because of shear and agitating it, so it’s delivered to the fountain in a smoother, more consistent form.”

In addition, “Sheetfed printers noticed that if their ink fountain levels went down, there was a change in the color they were printing, so they thought it was a good idea to keep the ink level constant,” Gray said. “When automation entered into filling the fountain of a large heat-set web presses, ball valves—liquid control valves—were adapted for the presses, but they’re designed to open and close only about 80,000 times and often wear out before their one-year warranties are up.”

Finding Solutions

Gray and INKnet developed a poppet valve to replace the ball valves, and these are designed to open and close 12 million times. Poppet valves are based on the concept that they could open and close frequently, maintaining a very tight control on ink fountain levels and stabilizing the print platform to reduce overall valve maintenance. INKnet also developed the first subsurface manifold to eliminate the ink mounding problems in conventional top-down drip manifolds. This dispensing system also lets printers cover the fountain to reduce paper and dust contamination.

All of the metering and tracking of ink flow at a variety of printing plants has given Gray certain unique insights. For example, in stacked web presses like Heidelberg’s Sunday presses, the meters on the lower webs detected an 18 percent increase in ink consumption compared to the top units. “This can cause some confusion, and lead operators to see quality variations,” he said. “It’s correctable if it can be seen—this has always been the problem.” But he added, “Ink goes where your eyes can’t see it.”

This is, perhaps, the greatest challenge of all. Monitoring ink properly requires understanding how new press technologies, paper and ink affect it, and figuring out methods to counteract the potential negatives. Gray is currently working with a client on all of these aspects of ink in the overall print process and expects to publish detailed data and statistics on the subject later this year. He’s also writing a primer on ink distribution plumbing systems. Often these systems are made from pipes developed to carry gas or water, but they’ve rarely been designed specifically for ink.

“Printers tend to take ink for granted,” he concludes. “They look everywhere else to identify problems.” Gray himself takes the engineer’s approach, looking at the realities of every press room, considering the basic properties of ink and how to move it where it needs to go while preserving its desired characteristics. What Gray has learned so far has clear applications in the press room, and can help printers reduce costs and improve quality.

Contact Jeanette Clinkunbroomer at jclink@aol.com.

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