Controlled Preparation of Chemically Produced Toner Particles by Suspension Polymerization with Hydrophobic Silica as Stabilizer

摘要

Toner particles whose average diameter ranges from 5 to 12 μm are synthesized by suspension polymerization in an aqueous phase. Styrene and butyl methacrylate are selected as monomers and hydrophobic silica as a stabilizer. Surface treatment is conducted to impart hydrophilic properties onto a hydrophobic surface. Filler particles such as carbon black, charge control agent, and polypropylene wax are weighed and then blended with the monomers to provide an even dispersion of components before the reaction. The reaction is carried out at a selected temperature between 70 and 90°C in a reactor equipped with a stirrer and temperature controller. Each toner particle is designed to contain a microstructure in which less hydrophobic components are placed on the outer surface and more hydrophobic ones are placed progressively towards the center. When the reaction is over, toner particles sediment and are separated. They are dried, after which external additives are added. Particle diameter is found to be a strong function of the amount of silica and a weak function of the reaction temperature and initiator. Glass transition ranges from 55 to 65°C, depending on reaction conditions.