Patent ID: 8865386

Claim:
A carrier core particle for an electrophotographic developer comprising: a core composition expressed by a general formula: Mn x Fe 3−x O 4+y (0<x≦1, 0<y) as a main ingredient; 0.1 wt % or more of Si; and 0.03 wt % or more of at least one metal element selected from the group consisting of Ca and Sr, wherein at least a part of the metal element exists as a complex metal oxide of Si, the complex metal oxide of Si being at least one selected from the group consisting of CaSiO 3 , Ca 2 SiO 4 , Ca 3 SiO 2 O 7 , Ca 3 SiO 5 , SrSiO 3 , Sr 2 SiO 4 and Sr 3 SiO 5 .