A comparative analysis of color performance, i.e., color gamut, image density, and lightfastness for a set of dyebased CM toner®, a set of commercial pigment-based color toner and a set of commercial inkjet ink was carried out. CM toner® was prepared by first forming small particles of a functionalized polyester resin and subsequently dyeing the particles with a dye to form a chemical bond between them.Three types of color performance were studied in detail; the color gamut of the toner sets, the optical density, and the lightfastness of the printed images. The dye toner set gave a larger gamut than the pigment toner set. The gamut number was used as an index to estimate an area of 2d gamut. The gamut number of dye toner was l.5 times larger than that of the pigment toner set and 2.4 times than that of the inkjet ink. For visualizing 3d gamut, Neugebauer model was adopted. From the comparison of 3d gamuts, the dye toners provided a gamut solid with larger volume than the pigment toners. The wide and larger gamut is primarily due to the high saturation and the lightness values, which in turn, result from that the dyes are dispersed in the molecular level due to intrinsic affinity to the base resin, whereas the pigments are dispersed in micro-scale due to poor affinity to the binder resin. The optical density per unit thickness was doubled by incorporating additional 1.5 wt.% of dye. To enhance the lightfastness of dye toner, a UV stabilizer was incorporated. The UV stabilizer improved the lightfastness to 80% level as compared to that of the pigmented toner, a value which was significantly superior to that of the inkjet ink.
Jongkwan Kim, Chul-Hwan Kim, Eui-Jun Choi, Hyun-Nam Yoon, "Color Performance of Dye-based and Pigment-based Color Toners" in Proc. IS&T Int'l Conf. on Digital Printing Technologies (NIP18), 2002, pp 827 - 830, https://doi.org/10.2352/ISSN.2169-4451.2002.18.1.art00102_2