| 摘要 |
PROBLEM TO BE SOLVED: To stabilize the rotation of a polygon mirror, to make a scanning optical device compact and to prevent dust from entering. SOLUTION: This scanning optical device 1 is constituted by being provided with an optical frame 1 whose upper part is opened and a cover body 3 covering the upper part of the frame 1 by housing a light source emitting a light beam, a rotary mirror 4 reflecting the light beam from the light source and lenses 5a and 5b forming the image of the light beam from the mirror 4 at the surface to be scanned of a photoreceptor in the frame 1. Then, a hole part 7 is formed at a position opposed to the mirror 14 of the cover body 2 and provided with a filter 8. |
