Coating Structure Effects On Ink-Jet Print Quality, 1997 Coating Conference Proceedings

Most high quality matte ink-jet sheets are coated with a system containing binder (typically polyvinylalcohol, PVOH), micronized amorphous silicas (typically silica gels) and other additives (e.g., cationic polymers). Print performance depends in a complex way on many factors, such as the printer, substrate, coating properties and coating application method. With regard to the coating, almost all variables effect print quality. For example, for PVOH binder, the degree of hydrolysis and molecular weight affect print performance. Within a particular coating formulation, however, the silica properties, such as porosity, surface chemistry, particle size and size distribution play the primary roles in determining ink-jet print quality. Within a relatively narrow experimental window (constant printer, substrate and coating formulation), the relationship between silica properties and print quality was investigated. Coated media were prepared using 15 silicas with varying and well characterized properties. Printed sheets were evaluated for color appearance and drytime. Surface roughness was also measured using Interferometric Surface Analysis Microscopy, and other properties (such as gloss) were measured as necessary. The highly porous silica gels give short print drytime and rapidly immobilize dyes and pigments on the coating surface in such a way as to produce colors with optimum color tone.