ROTARY POLYGON MIRROR AND OPTICAL SCANNER PROVIDED WITH THE SAME

PURPOSE:To provide a inexpensive polygon mirror and an optical scanner stabilized in quality by realizing the total reflection of a light beam on the inner side of a rotating body and easily forming the rotary polygon mirror and the optical scanner mounted on a copying machine, etc., and scanning the light beam. CONSTITUTION:This scanner is provided with plural transmission parts 16 provided around the rotating body 11 and made of transparent resin which transmits the light beam and has specified refractive index, a shaft center part 17 fixed on the rotary shaft of a rotation driving source, and a coupling part 18 coupling and supporting the transmission part 16 with the shaft center part 17, and the scanner is provided with an outer surface 12 forming the outer peripheral surface of the rotating body 11 and planar upper and lower reflection surfaces 14 and 15 opposed to the outer surface 12 and forming an included angle being 90 deg. in an axial direction in the transmission part 16, so that the light beam made incident on the transmission part 16 from a specified direction is totally reflected and emitted from one side to the other side by the reflection surfaces 14 and 15 because of the difference of refractive index between the transparent material and air.