| 摘要 |
PURPOSE:To obtain a magnetic powder dispersion type resin carrier having high magnetization enough to prevent attachment to a photosensitive layer by dispersing into an insulating binder resin, a fine magnetic powder obtained by coating the surface of each core with iron oxide. CONSTITUTION:A fine magnetic powder contains 25-85wt% metallic iron of cores and 15-75wt% iron oxide of surface films, and it has an average particle diameter of 0.1-1.0mum, a magnetization of >=70emu/gr in a 1 kOe, and a coercive force of 70-300 Oe. As an insulating binder resin, homopolymers of styrene and its derivs., and styrene and its derivs. copolymers, such as a styrene-isobutylene copolymer, thermoplastic resins, such as polyurethane, thermosetting resins, such as phenol resins, are used. The fine magnetic powder is used in 80- 400pts.wt. per 100pts.wt. of said binder resin. When needed, a colorant, such as pigment and dye, an auxiliary agents, such as resistivity controller or electrostatic charge controller, are added, the mixture is melted and kneaded, pulverized, and classified. |
