Recently, requests have been made that toners be able to fuse to paper with lower energy utilization. It has been reported previously that toners containing crystalline polyesters exhibited excellent fusing ability and that the lowering of these polymers's melting points was an effective means of improving fusing performance. On the other hand, the speed of printers and copiers has been increasing year by year, requiring the toner to have excellent durability properties. It is extremely difficult to satisfy both the durability and lower energy fusing requirements with the same toner as the properties work against each other. In this study, we have developed high molecular weight crystalline polyesters which allow us to obtain a high durability toner that also exhibits low energy fusing performance. Durability was achieved by increasing the molecular weight of the crystalline polyester, which is believed to also contribute to better dispersion of the toner additives. Moreover, it was found that the crystalline polyester'ss melting point was not affected by the molecular weight changes made in this study. Consequently, we were able to obtain both high molecular weight and a low melting point in these crystalline polyesters. As an added benefit, it has been observed that the high molecular weight crystalline polyesters also exhibit melt elasticity properties important for good toner antihot offset performance.
Takashi Kubo, Eiji Shirai, Katsutoshi Aoki, "Crystalline Polyesters for Use in High Durability Electrophotographic Toner" in Journal of Imaging Science and Technology, 2007, pp 185 - 189, https://doi.org/10.2352/J.ImagingSci.Technol.(2007)51:2(185)