| 摘要 |
PURPOSE:To secure a large distance from a curved surface mirror to a scanned surface (image plane, drum) even when the mirror of the reflection type scanning optical system which uses the curved surface mirror is reduced in size. CONSTITUTION:The reflection type scanning optical system consists basically of a deflector 11 which deflects luminous flux, a laser light source 14 which makes laser light incident on the deflector 11 at an angle of incidence in a subscanning direction, the curved surface mirror having a curvature at least in a main scanning direction which further reflects the laser light deflected by the deflector 11 with a separation angle in the incidence direction, and an anamorphic lens 21 system which is arranged between the curved surface mirror and the scanned surface. Then the anamophic lens 21 system is equipped at least with a surface whose main-scan sectional shape is aspherical and a surface which has a radius of curvature of subscanning section at a distance from the optical axis set irrelevantly to the main-scan sectional shape and has no axis of rotation. |
