| 摘要 |
PROBLEM TO BE SOLVED: To provide a synchronization device for a cascade-scanning optical system in which deviation in dots resulting from a couple of scanning laser beams in main a scanning and sub-scanning directions is prevented. SOLUTION: A recorder is provided with beam detectors 29A, 29B, that receive each scanning laser beam before an axial direction area of a photoreceptor drum is scanned, to detect a scanning timing, a 1st clock frequency divider circuit 53A and a motor unit 55A that drive either of a couple of polygon mirrors 24A, 24B at a constant speed, a 2nd clock frequency divider circuit 53B and a motor unit 55B that drive the other of a couple of the polygon mirrors 24A, 24B at a variable speed, and a counter 61 that counts rotation phase difference detected by beam detectors 29A, 29B. The 2nd clock frequency divider circuit 53B and the motor unit 55B drive the rotation of the other polygon mirror 24B at a variable speed in such a direction that the rotation phase difference is eliminated, based on a count counted by the counter 61. |
