Ink Transfer and Refusal Mechanisms in Waterless Offset Printing

Abstract

This study investigates the two possible mechanisms of ink refusal by the non-image area of waterless offset printing, i.e., the formation of a weak fluid boundary layer on the non-image area and the softening of the non-image area after contacting with ink. FT-IR–ATR, Micro-Indentation, AFM and a Deltack Printability Tester were used to analyze the plate surface before and after the plate–ink contact. Our results show that the dominant ink refusal mechanism is the softening of the non-image area caused by the possible diffusion of low molecular weight hydrocarbon components in ink diluents into the polymeric layer of the non-image area. The formation of a weak fluid boundary layer is also likely to contribute to ink refusal and may play a synergistic role.

Keywords:

• INK TRANSFER
• INK REFUSAL
• WATERLESS OFFSET PRINTING
• SURFACE FREE ENERGY
• WEAK BOUNDARY LAYER