| 摘要 |
An exposure device has a plurality of light emitting units for emitting laser beams based on image signals. These laser beams emitted from the respective light emitting units are combined through respective galvanomirrors and half mirrors and conducted through a cylindrical lens to a polygon mirror. The respective combined beams reflected on the polygon mirror are illuminated onto an exposure light position on the surface of a photosensitive drum through two ftheta lenses and a mirror. At this time, through the rotation of the polygon mirror, the respective laser beams are deflected in a main scanning direction and, through the rotation of the photosensitive drum, they are deflected in a sub-scanning direction to allow the surface of the photosensitive drum to be scanned with the exposure beams. At a position downstream of the cylindrical lens along a light path of the respective laser beams but upstream of the polygon mirror, a stop is so provided as to allow the combined beams to be passed and the cross-sectional configuration of the combined beams to be shaped. The stop shapes the cross-sectional configuration of the respective laser beams in the main scanning direction only.
|
