| 摘要 |
<p><P>PROBLEM TO BE SOLVED: To accurately perform a color shift correction even with changes over the ages. <P>SOLUTION: A correction pattern is formed on a transfer belt for a color shift correction. The correction pattern includes a black pattern on a base yellow pattern. A pattern detection sensor receives diffuse reflection light diffusely reflected from a surface of the transfer belt and the correction pattern, and outputs a light reception detection signal having an output level corresponding to a light amount of the diffuse reflection light. A CPU 109 performs a color shift correction by correcting a timing of superimposing each color image according to the output level of the light reception detection signal. Further, the CPU determines whether or not the black pattern is detected by the light reception detection signal, and when the black pattern is not detected, expands a width of the base pattern in the conveyance direction of the transfer belt when forming a correction pattern. <P>COPYRIGHT: (C)2013,JPO&INPIT</p> |
