CARRIER CORE MATERIAL FOR ELECTROPHOTOGRAPHIC DEVELOPER AND MANUFACTURING METHOD THEREFOR, CARRIER FOR ELECTROPHOTOGRAPHIC DEVELOPER, AND ELECTROPHOTOGRAPHIC DEVELOPER

摘要

PROBLEM TO BE SOLVED: To provide a carrier core material for a two components type electrophotographic developer excellent also in mechanical strength, while having sufficient surface irregularity enough to obtain high adhesiveness when coating resin. SOLUTION: This carrier core material uses, as a core material, a magnetic particle having 8.0 or more to 30.0 or less of value of BET specific surface area/true-sphere equivalent specific surface area, 0.050 μm or less of surface coarseness Ra value measured by reflection electron image analysis in a scanning electron microscope, and 2.40 g/cc or more of apparent density, by precipitating fine structure on a particle surface. The carrier core material is obtained by heat-treating rollingly the magnetic particle in a temperature range within 600°C-1000°C under a high reducing atmosphere. COPYRIGHT: (C)2009,JPO&INPIT