Influence of roughness and chemical surface properties on print quality of coated papers

Abstract

Our group studied how ink transfer, roughness and chemical surface properties affect the print quality of coated papers. In order to carry out this study, five glossy and three matte commercial coated papers were selected and characterised in terms of roughness and surface free energy. Each paper sample was printed with increasing amounts of a cyan offset ink, measuring print density, gloss and CIELab coordinates at each ink level. The results revealed high correlation coefficients for print density, L* and b* coordinates as a function of the square root of the ink transferred. The amount of ink required for 1.45 print density mainly depends on Bekk smoothness and the polar component of the surface free energy. For specific levels of ink transferred, print gloss, print density and b* coordinate were predicted by means of the contact angle between the paper surface and a vegetable oil used in offset inks.