| 摘要 |
PURPOSE:To compensate a fall of a rotary mirror, by using a cylindrical mirror lens which uses the plane side of a flat convex cylindrical lens to a reflector. CONSTITUTION:The plane of a flat convex cylindrical lens 6 is used as a reflecting surface, and a beam is made incident obliquely to the optical axis. Thus the optical path is folded by a reflecting surface and the beam focusing in the subscanning direction is performed simultaneously. The reflected light on the surface of the mirror lens 6 does not come back to a rotary polyhedral mirror as shown by dotted lines. This eliminates the generation of a static ghost and the flare. No dust nor toner is stacked since the lens surface is set downward. Then it is possible to use a cylindrical lens of a long para-axial focal distance owing to the fact that the beam is made incident obliquely to the lens 6. When a beam having 30 deg. inclination to the optical axis is made incident to the lens 6, the incident angle of the beam is set at 20.5 deg. to a photoreceptor. As a result, the ghost due to the reflected light scattered from the surface of the photoreceptor can be reduced. |
