Preparation of Pigment-Containing Polyester Toner by Chemical Milling

Abstract

We previously reported a novel method of chemically-preparing polyester color toner (CM toner®). The proprietary design of the first generation CM toner® was based on a functional polyester resin, a charge control agent, a wax, and dyestuff.Here we report an extension of the CM toner® technology to produce a pigment-based polyester color toner® Two innovations were incorporated in the technology. First, to disperse pigment particles finely in the toner particles and also to prevent exudation of pigment during chemical milling, we used a pigment master batch utilizing a polyester binder resin that is chemically similar to the toner resin. Secondly, we also developed a functional polyester resin containing an appropriate amount of a selected ionic functional group in the chain so that increased surface chemical potential of polymer droplets would overcome increased viscoelasticity of droplets containing pigment particles.Pigment CM toner® particles (pigment content as high as 10 wt. %) with the volumetric mean diameter in the range of 5-10 microns and the 80% span as low as 0.55 were produced. A four-color toner set was developed and it showed excellent imaging quality as well as a good printing page yield in a commercial color laser printer.