| 摘要 |
PROBLEM TO BE SOLVED: To provide a light beam scanner which improves the image quality and prevents deterioration of photosensitive characteristics due to optical fatigue of a photosensitive body for extending the service life of the photosensitive body by mechanically intercepting the optical path of a light beam for preventing a weak light beam output from being led by an optical device to irradiate an exposure position of the photosensitive body. SOLUTION: In order to form an image of a light beam L on the scanned face of an image carrier 9 with a required spot diameter required for image formation, the light beam L is made incident on a reflection face of a deflector 6, and the reflected light is made incident on image forming lenses 7 and 8 as an incident beam L'. Although the deflector 6 is rotated and driven at a high speed, it will have reduced rotation frequency or it stopped, when it is not forming images. This change in rotation brings about air pressure (negative pressure) proportional to the speed difference between the deflector and air around it, and a fin 12 provided with one side of a shielding plate 5 is shaken or rotated around a support point by this air pressure, to close or open the optical path of the light beam L.
|
