| 摘要 |
PURPOSE: To eliminate the difference in the scanning length between multi-beams by mutually tilting the beams toward the surface of a photoreceptor. CONSTITUTION: Lasers 10 and 11 are mutually tilted by an angleαwith each other. This differential tilt angleαapplies a little different scanning lengths to the beams of a photoreceptor surface 50 concerning a certain rotating angle of a polygon 12, and the more an incident angle I1 is reduced in the 1st reflection of facet 22, the longer the beam is scanned. Namely, a beam 5 scans the surface of a photoconductive drum 50 for the distance longer than a beam 5A and the excessive moving distance of this beam 5A enables the scan for long distance on the drum 50. Therefore, by properly selecting the tilt angle, the scanning length of beams 5A and 5 can be made equal. |
