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May 1, 2005 12:00 AM
For decades, printers have been searching for faster drying inks. Many have tried ink drying additives, specialty inks and aqueous coatings.
A proprietary ink additive from SpeedyDry Inc. (Charlotte, NC) accelerates the cross-linking reactions that normally occur in ink during drying. SpeedyDry is suitable for use with conventional offset lithographic inks and reportedly performs well on all stock types, even plastic. It has been in use for more than four years.
GATF breaks it down
Independent tests at the Graphic Arts Technical Foundation (GATF) (Sewickley, PA) proved SpeedyDry dramatically decreases ink drying time without significantly impacting print quality and ink properties, such as tone reproduction and tack. Additionally, GATF reported SpeedyDry improves rub resistance. Testing at GATF was performed as follows:
Printers familiar with this combination are used to two to three weeks’ drying time. Frank Kocialski, print production manager at Colorado Litho (Westminster, CO) says, "We ran solid reflex blue with SpeedyDry on an uncoated sheet, and an hour and a half later we varnished it and sent it to cutting. We had a lot of happy salespeople and cutter operators."
Shane Landis, cofounder of SpeedyDry Inc. and a press operator for more than 25 years, was involved in the development and testing. Tested stocks included:
|SpeedyDry stock test results|
|Stock||Normal Drying Time||Drying Time with SpeedyDry|
|Coated stock||3.0 hrs.||.09 hrs.|
|Uncoated cover stock||2.6 hrs.||1.9hrs.|
|Felt stock||10.4 hrs.||2.9 hrs.|
|Matte stock||3.5 hrs.||1.9 hrs.|
|Tipped polyester||10.7 hrs.||2.4 hrs.|
To get the Tipped Polyester to dry in 10.7 hours, the maximum time for tests, the sheets to be used for print analysis were pulled from the lift and left out in the open air. If the sheets had been left in the lift, GATF stated they wouldn’t have dried that quickly, if ever. These inks were not formulated for printing on plastic, but they dried hard with the SpeedyDry additive.
Dry, dry again
Landis claims SpeedyDry offers a greater flexibility than competing additives. "Current petroleum-based (liquid) drying additives are volatile," he says. "The solid paste types are not as volatile, but are not very effective. Ones with heavy metals repel water but need water to stimulate ink drying. Each type from each ink manufacturer has been developed for specific types of stocks."
Print buyers often request bright white stocks, which have more clay and more calcium than standard brightness papers. Typically, these stocks also take more time to dry. Rick Sherrard, director of the manufacturing specialty group at Quebecor World MIL Inc. (Ontario, Canada) recently tested SpeedyDry on a two-color job using a bright white stock with Hostmann-Steinberg inks and Fuji plates. Says Sherrard, "I would normally back it up in 24 hours because this is a very porous stock, but I was able to back up in 12 hours using SpeedyDry."
SpeedyDry users report the following benefits:
Spray powder reduction or elimination. Many printers use offset powder blown by compressed air into the delivery section of the press to prevent setoff in the lift. Landis says, "Depending on the stock, offset powder can be eliminated or reduced. This will also reduce powder getting in equipment downstream." Jack Gorman, GM of Printing Concepts (Erie, PA) concurs, saying he’s been able to reduce consumption of offset powder on a job-by-job basis.
Slip sheet elimination. Many companies add slip sheets between every sheet to eliminate setoff on the good sheets and move the job directly into binding or finishing. Kocialski says, "We use conventional cloth dampeners and therefore need a little more water. With the ink we were using, we were slip sheeting because two days later a job would still be wet. With SpeedyDry, we’ve eliminated slip sheeting."
More billable hours. "Before SpeedyDry, we had press operators do maintenance and cleaning while waiting for the first side to dry on a work-and-turn job or a job that had to be backed up," reports Gorman. "That was lost time—non-billable hours. Now, there is far less waiting time, and we don’t worry about setoff in the pile from the first pass."
Work-in-process inventory reduction. Press sheets that require drying time are moved from the back of the press and stored somewhere to dry, then moved to the next downstream process. SpeedyDry enables the skid to be moved only once, from the back of the press to the next piece of equipment, usually a cutter.
All of these factors add up to decrease the cycle time of a printed product. If a shop can print, fold and ship on the same day, as opposed to two to three days, it can dramatically increase its manufacturing capacity on an annual basis.
Ink drying issues
An ink additive can solve chalking, setoff, poor drying or striping problems.
Nancy Lowther is president of Lowther Training and Development. Contact her at (416) 282-1890.