| 摘要 |
PURPOSE:To correct a scanning position irregularity due to the plane tile of a rotary polygon mirror at low cost without using any special lens by deflecting a plane reflecting mirror in an ineffective scanning period according to the plane tile of each reflecting surface of the rotary polygon mirror in a plane perpendicular to the deflecting direction of each reflecting surface and fixing the mirror in an effective scanning period. CONSTITUTION:The device is equipped with the plane reflecting mirror 14 which is positioned between light source 11 and 12 and the rotary polygon mirror 15 and so arranged as to deflect luminous flux in the plane perpendicular to the deflecting direction of the rotary polygon mirror 15. Further, the device is equipped with a plane reflecting mirror driving means 25 which deflects the plane reflecting mirror 14 in the ineffective scanning period according to the tilt quantity of each reflecting surface of the rotary polygon mirror 15 in the plane perpendicular to the deflecting direction and fixes the mirror in the effective scanning period. Then the deflecting operation of the plane reflecting mirror 14 is performed in the ineffective scanning period and the plane reflecting mirror 14 is held at its deflection angle in the effective scanning period. Consequently, the scanning position deviation due to the plane tilt of the rotary polygon mirror 15 can be corrected at low cost without using any special lens. |
