Patent ID: 8343453
Filing Date: 2013-01-01
Classification: G03G

Abstract:
1. A manufacturing method of a carrier core material for electrophotographic developer, comprising the steps of: weighing and mixing prescribed raw material powders, then adding water to this mixture to prepare slurry, and granulating this slurry by spray-drying, to prepare precursor particles; sintering the precursor particles in a temperature range of 1000 to 1300° C., to prepare a sintered material containing magnetite or manganese ferrite; making this sintered material drop naturally into 2000° C. or more flame of flammable gas and oxygen from an upper side of this burning flame, or applying thereto heat treatment by dispersing this sintered material into the burning flame by using carrier gas, to form raised parts of striped pattern extending continuously in a plurality of directions while being superposed on one another, on a particle surface of a material to be treated; and obtaining the carrier core material having a desired particle size distribution, by classifying particles after this heat treatment by shifter.