Sheetfed Drying/Curing — A Cure-All for UV Inks
Hot air and infrared (IR) dryers, like their cousin, the UV curing system, play an important role in the print production process, much like a field goal kicker for a football team.
Think about it. When everything is going right, no one pays much attention to the kicker. But in critical situations, a missed field goal or botched extra point quite often results in dire consequences.
Likewise, a sheetfed press’ drying/curing system generally doesn’t garner any attention, unless it doesn’t perform the task at hand. Instead of boos from 50,000 people, the result is screams from one unhappy customer.
“I have always taken the position that a drying or curing system is not just an add-on accessory to the press, but actually an integral part of the press that can and will dictate its ultimate performance,” notes Bill Bonallo, president and CEO of technotrans america. “With sheetfed press running speeds ever increasing—exceeding 18,000 iph—the performance of the drying or curing system is even more critical.”
There are a number of factors influencing the way hot air and infrared dryers, along with UV curing systems, are manufactured. Bonallo notes several, including system integration into the press, how the addition of a dryer impacts sheet control, and dryer module interchangeability with other components.
Managing heat transfer to both the substrate and press components is another important variable, Bonallo stresses, as water cooling of both dryer and press components (like the delivery sheet guide plates) is generally necessary.
“With infrared and hot air, it is not just the power of the drying system relating to kW output, but how well the energy is transferred to the substrates that also needs to be considered,” he says. “Obviously, the continuous exchange of air in the drying zone is a critical factor in the drying process when a water-based coating is involved. Air flow must be balanced relative to sheet control in the delivery, which clearly can affect the ability to deliver sheets at fully rated press speeds.”