Patent ID: 6853815

Claim:
An image forming apparatus comprising: an image forming unit that forms images of an achromatic colorant and a plurality of chromatic colorants and superimposes the images to form a color image; a patch forming unit that has said image forming unit form a gray patch of said chromatic colorants and a gray patch of said achromatic colorant; a detecting unit that detects a chromaticity of the gray patch formed of said chromatic colorants and a chromaticity of the gray patch formed of said achromatic colorant using a color sensor; a comparing unit that compares a detection result of a chromaticity of the gray patch formed of said chromatic colorants with a detection result of a chromaticity of the gray patch formed of said achromatic colorant; and a controlling unit that controls an image forming condition of said image forming unit on the basis of the comparison result of said comparing unit.