Patent ID: 7553597

Claim:
A coated carrier comprising a carrier core material and a resin coating layer with which the carrier core material is coated, wherein the carrier core material consists essentially of a ferrite component having composition represented by the following formula (A): (MO) y (Fe 2 O 3 ) z (A) wherein y and z are each expressed in % by mol and are numbers satisfying the conditions of 40≦z<100 and y+z=100, M is a metal selected from Fe, Cu, Zn, Mn, Mg, Ni, Sr, Ca and Li, and MO is one or more oxides selected from oxides of these metals, at least one metal oxide (M L O) having a melting point of not higher than 1000° C. and at least one metal oxide (M H O) having a melting point of not lower than 1800° C., wherein the metal oxide (M H O) and the metal oxide (M L O) are contained in the ferrite component, the metal oxide (M H O) is at least one metal oxide selected from the group consisting of ZrO 2 , TiO 2 and Ta 2 O 5 , and the metal oxide (M L O) is at least one metal oxide selected from the group consisting of Bi 2 O 3 and P 2 O 5 , a part of the metal oxide (M H O) is independently present in the carrier core material for forming the coated carrier, a coercive force (Hc) of the carrier core material is not more than 50 Oe and the carrier core material has an average particle diameter of 15 to 70 μm.