Patent ID: 6251555
Filing Date: 2001-06-26
Classification: G03G,Y10T

Abstract:
Black magnetic composite particles for black magnetic toner, comprising:magnetite particle as core particle;fine particles which are adhered or exist on at least a part of the surface of each magnetite particle, and comprise oxides, oxide hydroxides or oxide and oxide hydroxides composed of at least one element selected from the group consisting of Si, Zr, Ti, Al and Ce; anda methyl hydrogen polysiloxane coating layer formed on the surface of the magnetite particles in which the fine particles are adhered or exist on at least a part of the surface of each core particle, in an amount of 0.1 to 50% by weight, calculated as SiO.sub.2, based on the weight of the magnetite particles on the surfaces of which said fine particles exist,the average particle size of said black magnetic composite particles being 0.08 to 1.0 .mu.m.