| 摘要 |
PURPOSE:To provide a rotary polygon mirror constituted so that the machining processing of a reference surface is reduced and the angular accuracy of plane tilt and the surface accuracy of a mirror surface are improved in the rotary polygon mirror used for a light deflection device. CONSTITUTION:By providing outside circumferential level difference 1d between the reference surfaces 1b and 1c mutually constituted of a parallel surface within the range of the inscribed circle and the circumscribed circle of the respective mirror surfaces 1a, the machining processing is reduced. When the reference surfaces 1b and 1c of the rotary polygon mirror 1 are superposed and the mirror surface 1a is processed to be piled in multistage, the receiving surfaces of the reference surfaces 1b and 1c become wide and the angular accuracy of the plane tilt formed by the reference surfaces 1b and 1c and the mirror surface 1a is improved. Besides, the occurrence of chattering or the like is suppressed because the intermittent machining part is reduced at a mirror surface processing time and the surface accuracy of the mirror surface is improved. |
