| 摘要 |
PURPOSE:To obtain a developer having stable electrostatic chargeability and superior durability by coating carrier particles with a material composed essentially of a specified epoxy type thermoplastic copolymer and incorporating a toner in said carrier particles in the range of a specified proportion of toner. CONSTITUTION:Carrier particles are prepared by coating iron oxide core particles having 30-1,000mum particle diameter with a material composed essentially of a thermoplastic copolymer of epichlorohydrin and 2,2-bis(p-hydroxyphenyl) propane or its deriv. On the other hand, toner particles are prepared having 85% integration frequency distribution exceeding 5mum particle diameter and about 8mum average paticle diameter. They are composed essentially of a condensate of 2,2-bis(4-hydroxyisopropoxyphenyl)propane and fumaric acid, and contain a small amt. of carbon black. An electrophotographic developer compsn. is prepared by mixing the 1.5-3.5wt% toner based on the carrier with it. The obtained developer thus obtained is stable in electrostatic charge per unit mass (Q/M unit muc) and superior in durability. |
