| 摘要 |
PROBLEM TO BE SOLVED: To form a high quality image without color smear in respective colors when a color image is formed using plural colors by outputting a position signal showing a position on a photosensitive body and controlling rotation drive of a rotary polygon mirror corresponding to after colors according to the position signal corresponding to an initial color among plural colors. SOLUTION: When a flag 10 fixed into a transfer drum 7 rotating synchronized with the photosensitive drum 5 at the same speed passes through a sensor 9, the sensor 9 generates a signal (ITOP signal) showing a tip position of a recording sheet to input it to an image write-out timing control circuit 1. Then, the photosensitive drum 5 is irradiated by an image signal as laser modulated beam synchronized with a scan start reference signal after a fixed time from the time when the ITOP signal detects a rise. At this time, a polygon mirror motor 17 is rotation controlled so that the rotational position of the rotor of the polygon mirror 3 driving motor 17 even when the ITOP signal after second color is raised becomes equal to the rotational position of the rotor when the ITOP signal of the initial color is raised. |
