Patent ID: 9034552
Filing Date: 2015-05-19
Classification: G03G

Abstract:
1. Carrier core particles for electrophotographic developer comprising a core composition expressed by a general formula: M x Fe 3-x O 4 , wherein 0<x≦1, and M denotes at least one kind of metal selected from the group consisting of Mg, Mn, Ca, Ti, Sr, and Ni as a main ingredient, wherein the carrier core particles have a volume size distribution with a median particle size ranging from 30 μm to 40 μm, the ratio of the carrier core particles having a diameter of 22 μm or lower in the volume size distribution is from 1.0% to 2.0%, the ratio of the carrier core particles having a diameter of 22 μm or lower in a number size distribution is between 3% and 10%, and magnetization of the carrier core particles in an external magnetic field of 1000 Oe is from 50 emu/g to 75 emu/g.