| 摘要 |
<P>PROBLEM TO BE SOLVED: To prevent image shifting and to prevent a great deterioration in productivity by making phase control matching rotational phases of rotary polygonal mirrors for each color unnecessary after switching rotational speed for the rotary polygon mirrors. <P>SOLUTION: After carrying out phase control so that phases of horizontal synchronization signal BD for each color are matched before starting a printing job, image writing timing is controlled by independently counting the horizontal synchronization signals for each color. Consequently, the image shifting can be prevented even when position relationship for each horizontal synchronization signal become unknown. Further, since phase control matching the rotational phases for the rotary polygonal mirrors for each color after switching the rotational speed for the rotational polygonal mirrors is not necessary, the deterioration in productivity can be prevented. <P>COPYRIGHT: (C)2008,JPO&INPIT |
