| 摘要 |
<P>PROBLEM TO BE SOLVED: To shorten the entire length of a pattern formed for detecting the amount of misregistration to reduce detection time and also reduce the amount of toner consumption. <P>SOLUTION: A misregistration amount detection pattern 100 which moves in a fixed direction is detected with a sensor, thereby detecting the amount of misregistration in image formation. In this case, the misregistration amount detection pattern 100 is formed of reference color patches 101 that define a reference-color image forming position, and a non-reference color patches 102 that define a non-reference-color image forming position. Each reference color patch 101 and each non-reference color patch 102 have narrower sub-scanning width than a beam spot diameter WS. The amount of shift of each non-reference color patch 102 relative to each reference color patch 101 is set so that positive/negative symmetry is established. On the basis of a pattern detection period obtained from the output of the sensor for the misregistration amount detection pattern 100, the amount of misregistration is calculated. <P>COPYRIGHT: (C)2004,JPO&NCIPI |
