SHEETFED DRYING/CURING SYSTEMS -- Running Hot and Cold
BY MARK SMITH
UV rays beating down. Hot air blowing across the skin. Catching some waves. Sounds like a great day at the beach.
In the sheetfed offset printing arena, those descriptions also fit three technology options for boosting quality and speed—UV curing and drying with hot air knives or IR (infrared) energy. Market pressures are dictating that printers implement some form of drying/curing capability, but the "right" choice of technology remains an open question.
"With a multicolor machine plus coater now being the standard for modern sheetfed presses, adequate drying systems have become a must to achieve the highest quality results," notes Bill Whitehead, director of sales, sheetfed products, for Oxy-Dry Corp. in Itasca, IL.
In addition to boosting print quality, drying systems enable the faster turnaround times being demanded by print buyers, notes Margaret Bain, marketing coordinator at Accel Graphic Systems in Dallas. As an added benefit, they reduce spray powder usage and set-off or blocking, she points out.
"The fastest growing drying/curing technology is ultraviolet (UV) systems. UV inks and coatings produce bright, intense colors and extremely high gloss," Bain says.
"Today, with some form of coating specified on almost every job, dryers no longer can be considered an accessory," asserts Bill Bonallo, president of technotrans america in Corona, CA. "They are, in fact, an integral component of the press itself that can and will dictate the overall press performance, particularly in the area of running speed and press up time."
Whitehead sees the use of UV coatings, specifically, as a pivotal decision in the approach to drying/curing taken by a sheetfed printer. Sheets that are run with conventional inks need to dry or be sealed before a UV coating can be applied, which necessitates a separate pass for the coating, he points out. "Using a hybrid or full UV ink system provides the capability to UV coat in-line, while retaining the higher gloss levels and much greater rub resistance offered by the process."