surface first. On the other hand, the mineral-rich papers use the porous structure of coatings to drain the solvent by capillary effects, still keeping the pigments on top. Because of higher printing speeds of the new generation of ink-jet printers and the shorter drying times of mineral-rich papers (4), the polymerrich papers are expected to be progressively replaced by highly structured mineral-rich papers as the print quality of the latter meets that of the former.
ON THE USE OF NANOPOROUS SILICA PRODUCTS AS INK HOLDER AGENTS FOR INK-JET PRINTING. Jean-Philippe Boisvert1, Jacques Persello2 and Aurélien Guyard1 1
CRPP, Université du Québec à Trois-Rivières,C.P.500,TroisRivières,Québec, G9A5H7 2 LCMI, Université de Franche-Comté, 16 route de Gray, 25000 Besançon, France.
It is now well known that many factors affect the structural properties of paper surfaces, which include the substrate, the coating formulation, the coating application method and the coating drying conditions (5). Following the pioneered work of LePoutre (6) in this matter, numbers of workers are still investigating the relationship between the print quality (in general) and these factors (see for instance references (4, 7-12) and the references therein).
RÉSUMÉ Deux types de produits SiO2 poreux utilisés comme agents de retention d’encre ont été synthétisés et caractérisés. Leur interaction avec le polyvinylalcool (PVA) a été étudiée. Un papier non-couché a été utilisé comme référence comparative pour des tests d’impression jet-d’encre. Ce papier a été couché avec des mélanges SiO2/PVA puis testé en impression. À partir des resultants présentés, des concepts généraux impliqués dans l’impression jet-d’encre sont identifés. Premièrement, la qualité d’impression dépend du rapport taille de pore/taille de polymère. Deuxièment, l’intéraction polymère-surface influencerait aussi la qualité de l’impression.
Although not clearly expressed this way in the literature, the print quality of mineral-rich coatings for given ink can be related to at least two different parameters; the porosity (pore size, size distribution, porous volume) and the surface chemistry of the pores (surface tension and chemical affinity with additives). In line with this observation, porous minerals like silica gel and precipitated silica have been tested for their high print qualities and fast drying times (2, 4, 13, 14). It has been shown that drying times and the print quality (tone and spatial resolution) with these products are improving as the pore size is decreasing (4, 13). In general, such materials have a high porous volume (>0.5ml/g) and low mean pore size (
