The influence of ink pigment penetration and paper structure on print through

摘要

A method to quantify ink pigment penetration using scanning electron microscope (SEM) and image analysis is described. The method is based on quantification of clay particles present in yellow coldset offset ink. To test the method a 3x3 statistical experiment was designed. The amounts of fines, chemical pulp and calendering were the variables studied in the experiment. Ink pigment penetration, print-through, optical properties and structural properties of the handsheets were determined. All three variables had significant effects on the print- through measurements. Increased amount of fines in the paper reduced the print-through, while increased amounts of chemical pulp and calendering increased the print-through. All three varibles had effects on the print-through partly due to the changes they caused in the light scattering coefficient of the paper. However, both calendering and increased amount of fines reduced the average depth of ink pigment penetration into the paper. A model describing the print-through as a function of light scattering and ink pigment penetration depth explained 86% of the data variation.