Patent ID: 7817941

Claim:
A color image forming apparatus, comprising: a plurality of developing devices; each of the plurality of developing devices having: a developing roller including a cylindrical developing sleeve arranged at a position opposite to an image bearing member, supported to be rotatable, to carry developer including toner and carrier, to convey the developer to the image bearing member, and a fixed magnetic pole member arranged inside the developing sleeve and including a plurality of fixed magnetic poles formed in a peripheral direction; an agitating member to agitate developer; a recovering and feeding member supported to be rotatable, to feed developer to the developing roller and to recover developer from the developing roller; a regulating member to regulate an amount of developer fed to the developing roller; and a developing device casing member to store developer therein and to accommodate the developing roller, the regulating member, the agitating member and the recovering and feeding member therein; wherein at least one of the plurality of developing devices has a different developer storing capacity and a different outer diameter of the recovering and feeding member than the other developing devices and has the same angle allocation values among the plurality of fixed magnetic poles in the fixed magnetic pole member, and all of the developing sleeves of the plurality of developing devices have the same outer diameter.