Novel aqueous pigment dispersions containing only dye as the pigment stabilizer are discussed. These dispersions contain well-dispersed and stable pigment, dye and water. The dyes employed are of high purity and are commonly utilized as ink jet dye colorants. Optionally, humectants such as glycols or glycerines may be added, as well as amines and biocides.The resultant dispersions have very fine particle sizes and high surface tensions, and have a low tendency to flocculate when reduced back in prototypic ink jet ink formulas. Additionally, low and stable viscosity ink profiles are obtained when using these dispersions to color prototypic ink jet inks.Development work focused on black dispersions. However, process colors are discussed, as well. These dispersions allow the ink to have hybrid properties of a pigment and dye, without the limitations imposed by the inclusion of traditional dispersants, such as surfactants or polymers.
Mark Ortalano, "Novel Hybrid Pigment/Dye Dispersions" in Proc. IS&T Int'l Conf. on Digital Printing Technologies (NIP16), 2000, pp 628 - 631, https://doi.org/10.2352/ISSN.2169-4451.2000.16.1.art00052_2