If an ink jet is applied to an office printer, it is important to obtain high optical density on plain paper, consistent with that of a laser beam printer. Also, on the point of durability and water resistance, pigment inks have advantages for office use over dye inks. Encapsulated pigment inks that are coated with water-insoluble polymers in particular can achieve high optical density, compared with conventional pigment inks, which are dispersed by water-soluble dispersants.For this paper, to use these encapsulated pigment inks effectively, we prepared several encapsulated pigment inks, which had different wettability and penetration ability on plain paper, and investigated the relationship between their properties and their optical density on plain paper. We found that inks with both high wettability and low penetration ability indicate high optical density. To confirm the cause(s) of these results, we measured the ratio of white spot to solid image by image processing. We also examined the depth profile of the pigment from the paper surface by TOF-SIMS analysis.
Yasuhiro Doi, Hiroyuki Yoshida, Isao Tsuru, "The Effect of Properties of Encapsulated Pigment Inks on Optical Density" in Proc. IS&T Int'l Conf. on Digital Printing Technologies (NIP22), 2006, pp 189 - 192, https://doi.org/10.2352/ISSN.2169-4451.2006.22.1.art00048_1