Patent ID: 8039189
Filing Date: 2011-10-18
Classification: G03G

Abstract:
1. A carrier for an electro photographic developer, comprising: magnetized core material particles and a resin layer covering each surface thereof, wherein the weight average particle diameter, Dw, of the core material particles is in the range of 22 μm to 32 μm, the ratio of Dw to the number average particle diameter, Dp, satisfies the condition, 1<Dw/Dp<1.20, the content of particles smaller than 20 μm in diameter is in the range of 0% by mass to 7% by mass, the content of particles smaller than 36 μm in diameter is in the range of 90% by mass to 100% by mass, and the BET specific surface area of the core material particles is in the range of 300cm wherein the core material particles comprise ferrite a surface of which is treated with a smoothing treatment obtained by calcinating particles of metal oxides in a rotary kiln.