Patent ID: 7097270
Filing Date: 2006-08-29
Classification: G03G,H04N

Abstract:
1. A control method in an image forming apparatus which forms an image with an achromatic colorant and images with a plurality of chromatic colorants and superimposing those images to form a color image on a transfer sheet, wherein said method comprises the steps of: causing the image forming apparatus to form a plurality of gray patches by mixing a plurality of chromatic colorants while changing a mixture rate of the chromatic colorant in several ways; causing the image forming apparatus to form a gray patch with an achromatic colorant; detecting, by using a color sensor, a chromaticity of each of the gray patches thus formed; obtaining, by calculating based on a result of said detection of a plurality of gray patches with mixed chromatic colorants and a result of gray patch with an achromatic colorant, respective gradients of a gray with the plurality of chromatic colorants that would have the same chromaticity as the gray patch formed with the achromatic colorant; and controlling an image forming condition of respective chromatic colorants based on a result of said step of obtaining respective gradients of a gray.