PRODUCTION METHOD OF CARRIER CORE MATERIAL FOR ELECTROPHOTOGRAPHIC DEVELOPER, CARRIER CORE MATERIAL FOR ELECTROPHOTOGRAPHIC DEVELOPER, CARRIER FOR ELECTROPHOTOGRAPHIC DEVELOPER AND ELECTROPHOTOGRAPHIC DEVELOPER

摘要

PROBLEM TO BE SOLVED: To provide a production method of a carrier core material for an electrophotographic developer, by which a carrier core material for an electrophotographic developer achieving a smaller particle diameter, having an appropriate size of crystals on a particle surface and achieving high strength can be produced.

SOLUTION: A production method for a carrier core material for an electrophotographic developer includes: a slurry preparation step (A) of preparing a slurry of a raw material containing iron and a raw material containing strontium; a granulation step (B) of granulating the obtained mixture after the slurry preparation step; and a calcination step (C) of calcining the powdery material granulated in the granulation step at a predetermined temperature to form a magnetic phase. In the slurry preparation step, the raw material containing iron is prepared into a slurry in such a manner that the raw material containing iron has a volume particle diameter D50of 1.0 to 4.0 μm and has a volume particle diameter D90of 2.5 to 7.0 μm; and the raw material containing strontium is prepared into a slurry in such a manner that the content y of strontium to be included in the carrier core material for an electrophotographic developer satisfies 0COPYRIGHT: (C)2013,JPO&INPIT