| 摘要 |
<p>In a color image forming apparatus, a color toner patch for controlling density or chromaticity may be detected by a color sensor (42) and fed back to process conditions so as to control density or chromaticity of a final output image. In the present invention, a gray patch of black (61) and a process gray patch (62) of yellow, magenta and cyan are formed on a transfer medium (11), the chromaticity is detected without using a criterion for sensor output proofreading, and relative comparison is made between the chromaticities detected from the above two types of gray patches by using as a standard the gray patch of black which is almost achromatic, and if the chromaticities are consistent with each other, the process gray patch is judged to be achromatic. <IMAGE></p> |
