| 摘要 |
PROBLEM TO BE SOLVED: To provide a carrier core material for an electrophotographic developer, a carrier and a method for producing the carrier core material and the carrier, in which heavy metals are not used, the Mn content is reduced as much as possible, and high magnetization, high resistance and less aggregated particles are achieved, and to provide an electrophotographic developer having a high charge amount, excellent charging stability and a long lifetime. SOLUTION: The carrier core material for an electrophotographic developer contains Mg by 0.8-3 wt.%, Ti by 0.5-2.4 wt.%, Fe by 60-70 wt.%, Sr by 0.3-2 wt.%, Mn by 0.001-4 wt.%, and Si by 50-1,000 ppm, showing 50-1,000 ppm elution of Sr with a pH4 standard solution, and contains particles having a shape factor SF-1 (circularity) of 135 or more by 12% by number. COPYRIGHT: (C)2011,JPO&INPIT |
