Patent ID: 8891987

Claim:
A color image forming apparatus comprising: an image bearing member for carrying an electrostatic latent image; a plurality of developing devices for effecting a developing operation for developing the electrostatic latent image; a supporting member, supporting said developing devices, for moving said developing devices sequentially to a developing position opposing said image bearing member; a detecting device for effecting a detecting operation at a position different from the developing position for detecting information relating to a developer remainder in said developing device; deducing means for deducing a consumption amount of the developer from image information; and determining means for determining the developer remainder, wherein in color image formation, as to said developing device of said developing devices for which the detecting operation of said detecting device is effected after the developing operation therefor, said determining means determines the developer remainder from the information relating to the developer remainder detected by said detecting device, and as to said developing device of said developing devices for which the detecting operation of said detecting device is effected before the developing operation therefor, said determining means determines the developer remainder from the information relating to the developer remainder detected by said detecting device and the consumption amount deduced by said deducing means.