Colorant Migration in Mesoporous Inkjet Receptive Coatings, 2006 TAPPI Advanced Coating Fundamentals Symposium

The majority of printers currently used for colour printing in offices and homes are inkjet printers. Because of its ability to print on a wide variety of substrates, inkjet technology is also increasingly used in industrial printing and in the package printing industry. The final print quality is largely dependent on the ink-substrate interaction. High quality colour prints are achieved using specialty coated substrates, usually consisting of mesoporous pigments and polymeric binders. The focus of this study was on inkjet colorant migration in mesoporous coatings and its relation to print quality. The influence of factors such as coating pigment type, binder concentration and ink composition on printability were assessed by microscopy and optical print quality measurements. The results indicate that pigments with large pores required more binder than pigments with smaller pores, as that reduced the internal pore volume for ink solvent uptake, with a lower gamut area as a result. A partially hydrolysed PVOH binder gave the highest print quality and sufficient binding strength with all the pigments. The print quality was also influenced by the choice of ink. In general, a dye-based ink gave the highest gamut area, whereas a pigment-based ink gave the highest print sharpness.