September 10th, 2007 – The PIA/GATF Intertech award winning Goss DigiRail digital inking technology is now available for commercial web presses.
DigiRail systems can be retrofitted on to some existing Goss presses and are an option for new Goss M-600 and gapless Sunday press models. The highly precise digital inking technology replaces traditional ‘open fountain’ ink delivery, reducing waste while improving print quality.
“Bringing digital inking to commercial web applications is another Goss International R&D breakthrough,” confirms Goss International CEO, Bob Brown. “This is a technology that can enhance the efficiency and performance of a new press or an existing press.” Brown emphasized that DigiRail technology joins the Sunday press, Autoplate, Automatic Transfer, Ecocool and other exclusive, integrated Goss innovations that make commercial web printers more successful and the web offset industry more competitive.
The DigiRail system earned the PIA/GATF Intertech Award in 2003. The technology replaces traditional analog ‘open fountain’ ink delivery with digital ink pack devices housing low-torque, in-line gear pumps. The pumps feed ink pulses to the ink train through individual valves which are controlled digitally. More than 50,000 individual ink packs have been installed and are highly proven on Goss newspaper and insert presses worldwide.
Digital control of ink flow complements digital workflow and presetting capabilities and offers several fundamental benefits, according to John Dowling, engineering director in the Goss International Research and Development Department.
“Because ink is delivered to the ink train with more precision and with no contamination, presetting is faster and more accurate, start-up waste can be reduced, and ink density and color variation issues are minimized during operation,” explains Dowling. “After extensive testing on demanding technical forms, and minor modifications, DigiRail technology can now bring these same benefits to commercial presses printing at up to 100,000 impressions per hour,” he adds.
The DigiRail system includes a series of ink pack devices mounted on an aluminum rail against the first ink roller. Each ink pack for commercial web applications has a synchronous AC motor and 12 individual ink metering valves which operate in a binary on/off fashion. The valves are each pulsed by separate digital signals, and varying the ‘on time’ of the pulses allows precise ink volumes to be delivered. The number of ink packs varies according to web width, with the individual valves covering zones equivalent to those of a traditional ink key.
“The flow of ink to the metering valves is constant for a given press speed, and the amount of ink fed to each 40-millimeter zone across the web is adjusted to match ink coverage requirements by changing the digital on/off pulse rate of each valve,” Dowling explains. “As a result, ink adjustments can be made in increments as small as 1 percent, the response is predictable and repeatable, and the ink volume is not sensitive to temperature or viscosity.” He points out that excess ink is recirculated within the sealed system, reducing consumption and contamination from lint, paper dust or dampener solution.