Particulate or pigmented inks for thermal ink jet applications exhibit great print quality, far superior to dye based inks. In this paper, we present concept for the development of kogation-free pigmented inks by imparting polymer latex into ink jet inks. Inks are prepared by the addition of polymer latex, and wherein the polymer latex can act as a stabilizer to improve the stability of pigmented ink. The polymer latex can also function as a binder with carbon black colorant or other color pigments, thereby impart the ink smear resistance, film hardness, and humidity resistance. The addition of polymer latex also develops a list of attributes such as high optical density, good latency, excellent light- and waterfastness, superior black MFLEN, good frequency response, and excellent cool curl and showthrough properties.Polymer latexes are prepared by emulsion polymerization process. Polymer latexes that are useful in ink jet applications include ionic sulfonate polymer latex, epoxy polymer latex, polymer latex with a high glass transition temperature (Tg), or polymer latex with a nonionic surfactant with an HLB (hydrophilic/lipophilic balance) value from 17.5 to 20.
Chieh-Min Cheng, Garland J. Nichols, Min-Hong Fu, "Developing Pigmented Inks for Thermal Ink Jet" in Proc. IS&T Int'l Conf. on Digital Printing Technologies (NIP18), 2002, pp 762 - 765, https://doi.org/10.2352/ISSN.2169-4451.2002.18.1.art00085_2