摘要 |
Light sources emit light beams onto deflecting surfaces of a deflecting unit through incident optical systems. The deflecting unit deflects the light beams in a uniform direction to form images onto different surfaces to be scanned through imaging optical systems. An optical path length, or a distance from a deflection point of the deflecting unit to a surface to be scanned, of an imaging optical system to form an image onto a surface to be scanned closest to the deflecting unit is different from that of an imaging optical system to form an image onto a surface to be scanned farthest from the deflecting unit. Also, the following condition is satisfied: 0.85<K1/K2<0.98 where K1 is a Ktheta coefficient of an imaging optical system with a short optical path length, and K2 is that of an imaging optical system with a long optical path length.
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