THERMAL DIGITAL PLATES VERSUS PROCESS FREE PLATES IN HEATSET WEB OFFSET

This paper presents conclusions derived from testing the new type of process free plates during normal production runs obtained on offsets, heatset type printing machine, compared to developed thermal digital plates. The plates were compared based on quality of the print, durability and cost effectiveness. On the surface of the plate there are printing areas and non-printing zones that behave differently. The printing areas are oleophilic and at the same time hydrophobic to which the ink adheres. Non-printing zones have an opposite behaviour being hydrophilic and thus oleophobic. In order to achieve the required quality of the printed product, the developed thermal digital plates have to be very stable across the tonal range and the normal life cycle of the developing solution in the processor bath. With the process free plates, there is no need to develop the plates, the removal of the nonprinting coating being done under the action of the dampening solution present on the printing machine rollers.