| 摘要 |
PURPOSE:To provide merits of a rotary polygonal mirror and also practically eliminate the influence of inclination by providing a light deflecting means with a rotary mirror member which has a curved surface part and a plane part in the side part and using the plane part for optical scanning but not using the curved surface part for optical scanning. CONSTITUTION:A rotary mirror 3 has merits of a polygonal mirror, and a part 3a of a cylindrical metal, especially, nonferrous metal having a thickness is cut to plane to obtain the rotary mirror 3, and the one face of the side part 3a is used as a reflecting surface. Consequently, a large moment of inertia is obtained and rotation is stabilized and the mirror 3 is suitable for high-speed rotation. If the mirror surface is inclined at b-number of sedonds to the revolving shaft of a motor 13, the reflected luminous flux is inclined at 2b-number of seconds, but the reflected luminous flux is inclied at 2b-number of seconds similarly because the mirror has one surface when the luminous flux is reflected on the mirror surface again after one rotation of the motor. Thus, the degradation of image due to inclination is prevented and the use of a special inclination correcting optical system is unnecessary. |
