Toner Layer Structure and Toner Adhesion on Coated Paper

Abstract

In electrophotography the toner adhesion to paper is an important quality parameter. All main components of printing - toner, paper and process - have an effect on the adhesion level. The objective of this study was to clarify the role of coated paper properties in adhesion. According to previous studies, both mechanical and chemical adhesion phenomena are involved when paper is the receiving layer.The sample set included electrophotographic prints on coated papers, where the ratio of different coating pigments was varied. The series contained both uncalendered and calendered samples. Alterations in coating pigments and calendering caused the samples to have different surface properties. Variations in roughness and porosity together with the surface energy induced changes in toner layer formation on different types of coatings. Vibrational spectroscopic methods, i.e. FTIR and Raman measurements, were used to study the structure of the layer of the polyester toner and the chemical phenomena in more detail. FTIR-ATR measurements made from the very surface and depth profiling with Step-scan PAS proved that the molecular structure of the polyester toner layer changes as a function of depth. The confocal Raman technique was used to examine the composition of the toner-paper interface further.