The Influence of Blanket Type on Printing

Abstract

The development of print gloss is reported for the first time using actual printing inks, coatings and press blanket materials. The print gloss for several blanket textures is measured and the results show that the surface structure of the blanket material has a significant influence on print gloss development. Higher blanlet roughness correlates with low gloss. A model, based on the surface tension driven leveling of an ink filament, is proposed to predict the print gloss right after printing. This model predicts the correct gloss dynamics and gives insight into the length scale related to the blanket texture. Ink tack on the press blanket texture is also measured by a rolling nip device, which detects the separation forces at the nip exit. The influence of blanket type on the maximum and minimum pressures is reported. Rough blanket textures are found to correlate with smaller tack forces. The reduction of tack force with increase blanket texture is thought to be related to the earlier onset of cavitation at the nip exit.