Patent ID: 7452651

Claim:
A carrier comprising carrier particles; each carrier particle comprising a carrier core and a coat layer for coating the carrier core, wherein; said carrier core has a ferrite component, and the ferrite component contains i) a metal oxide having at least one metallic element selected from the group consisting of Mg, Li and Ca, where the total-sum content of the metal oxide having at least one of the metallic elements Mg, Li and Ca is from 15 to 30 mole % based on the whole ferrite component, and ii) a metal oxide having at least one metallic element selected from the group consisting of Mn, Cu, Cr and Zn, where the total-sum content of the metal oxide having at least one of the metallic elements Mn, Cu, Cr and Zn is from 50 to 4,000 ppm on mass basis based on the whole ferrite component; said carrier has a volume distribution based 50% particle diameter (D50) of from 15.0 μm to 55.0 μm; said carrier has a degree of surface unevenness of from 1.05 to 1.30; and said coat layer contains particles, and the particles have a number-average primary particle diameter of from 10 nm to 500 nm.