Danish flexo press and printing ancillary product manufacturer TRESU Group has unveiled an in-line, pressure-controlled varnishing concept for high-speed, sheet-fed and web offset printing presses. Suitable for UV- and water-based varnishes, the TRESU Offset Coating Concept will be a highlight of TRESU’s drupa stand in Hall 10-A62.

Based on TRESU Ancillary´s flexo technology, this new self-regulating concept comprises the TRESU UniPrint Combi chamber doctor blade E-line and TRESU Coating Circulator and a TRESU Coating Conditioner. This system will enable sheet-fed and web offset printers to coat printed products at faster speeds, without the risk of micro-foaming and blisters in the coated surface caused by the transfer of air into the coating from the anilox roll cells.

A key feature of the concept is the company’s Pressure Control Technology. This ensures a sufficient pressure so that a constant barrier is maintained between the chamber doctor blade and the rotating open anilox cells, preventing air-bubbles from entering. The UniPrint Combi chamber doctor blade features TRESU’s patented Seal System. Rubber seals form a perfect, airtight closure, eliminating leakage at speeds of up to 18,000 sheets per hour. It also comes with the patented E-Line doctor blade changing system for safe blade change within one minute. Furthermore, the Streamlined and compact designed chamber allows fast, effortless changeover by sliding and locking into position with ease. This minimises coating agitation and optimises productivity.

Working in harmony with the UniPrint Combi is the TRESU Coating Circulator iSeries. The circulator automatically adjusts to the coating supply and initiates either a 6-minute or intensive 12-minute cleaning program, enabling fast job changes. A choice of circulators is available to suit a wide range of UV and aqueous coating types. By means of a sensor to measure coating volumes and press speeds at the doctor blade, the circulator regulates coating consumption.

Temperature regulation for UV coatings is achieved with TRESU’s new Coating Conditioners, which feature an automatic re-filling system to maintain coating quantity and temperatures of up to 55ºC.

Henrik Kristensen, TRESU Ancillary sales director of the TRESU Ancillary division, comments, “In-line varnishing – using the flexo process - is a preferred method of coating offset printed products, but until now printers have faced the risk of blistering due to the foaming of the coating when running at high speeds. TRESU’s new Offset Coating Concept, with pressure control technology, finally enables offset printers to achieve the highest in-line varnishing finish and reach full performance potential of their press.”

The New Offset Coating system is suitable for a wide range of sheet-fed and web offset applications where a perfect coating finish is needed, such as high-value glue-applied paper labels, carton board packaging and in commercial print as well as some web-fed offset applications like shrink-wrap sleeves.