| 摘要 |
PURPOSE:To reduce wind whistle at the time of when the rotary polygon mirror is rotated at a high speed, and to prevent each mirror face from being contaminated. CONSTITUTION:The rotary polygon mirror 1 has the rotary reflecting surface 1A consisting of mirror surfaces 1a-1f being parallel to its rotary shaft, and also, being adjacent to each other, and between each mirror surface 1a-1f, chamfering is performed by a small inclined surface 1O. Each small inclined surface 1O is formed so that an angle made by the mirror surface being toward the front in the rotational direction becomes small by making chamfered width A of the mirror surface being toward the front in the rotational direction of the rotary polygon mirror 1 larger than chamfered width B of the mirror surface being toward the rear thereof, by which air resistance at the time when the rotary polygon mirror 1 is rotated is reduced. |
