Abstract High performance, full color electrophotographic printers are gaining acceptance in many office environments. In this study, the authors controlled the aggregation of three different colloidal dispersions using four different multivalent metallic coagulants over
a wide pH range to develop a polyester-based chemically prepared toner (CPT). An operational limit existed for the total quantity of each metallic coagulant required to achieve a narrow particle size distribution at a mean target aggregate size. This, when exceeded, produced a viscous, inoperative
sludge in the reactor. The optimal pH condition for each coagulant system was mainly dependent on the electrostatic balance produced by deprotonation of exposed carboxylic acid groups on the polyester resin particles at a pH between 5.5 and 6.5. Additional electrostatic interactions between
the polyester colloidal dispersions and the monovalent cations (M1+) in the metallic coagulation system at high electrolyte concentrations created a favorable environment to reproduce core-toner particles with a narrow particle distribution at a mean target size. By manipulating
the aggregation process, the individual nano-dispersions coalesced in an aqueous environment to form a polyester-resin-based chemical toner that was uniform in particle size and had low total volatile organic compound (VOC) level. The printing and image performance of this toner using a color
laser printing system was also observed. This final polyester toner was optimized for high speed, energy efficient electrophotographic printers that utilize an oil-free fusing subsystem that operates at a low fusing temperature. The image quality and toner usage of these toners meet the specifications
of major printer manufacturers for digital printing technologies.