| 摘要 |
<P>PROBLEM TO BE SOLVED: To provide a method for manufacturing a carrier core material for an electrophotographic developer, the material having high magnetization, a medium to high resistance, superior charging characteristics, appropriate ruggedness of the particle surface and a uniform shape, substantially without using various heavy metals and Mn. Ž<P>SOLUTION: The method for manufacturing a carrier core material for an electrophotographic developer, containing Fe, Mg, Ti and Sr and having a spinel structure and a Ti compound structure includes: (1) a first calcination step of mixing and calcining a Mg compound, a Ti compound and Fe<SB>2</SB>O<SB>3</SB>in a non-oxidative or weak-reducing atmosphere to obtain a mixture containing a divalent Fe; (2) a granulation step of granulating slurry particles: (3) a second calcination step of calcining the granules in a non-oxidative or weak-reducing atmosphere to convert the granules into a ferrite; (4) a third calcination step of further calcining the ferrite to adjust the magnetization and surface properties; and (5) an oxidization film treatment step. In the first calcination step or in the granulation step, at least one kind selected from Fe, Mg, Ti, Mn and Sr is added. Ž<P>COPYRIGHT: (C)2010,JPO&INPIT Ž
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