Patent ID: 7411710

Claim:
An optical beam scanning device comprising: a deflecting unit that holds a light source that irradiates an optical beam and a deflecting member that deflects the optical beam irradiated from the light source at a constant velocity after the optical beam is deflected at a constant angular velocity in a predetermined deflection plane, the deflecting unit integrally holding the light source and the deflecting member while maintaining their position relative to each other; and a support member that supports a reflecting member that reflects the optical beam deflected at a constant velocity by the deflecting member toward a scanning target supported by a main apparatus, and also supports the deflecting unit such that the positions of the light source and the deflecting member relative to the reflecting member are preserved, the support member being supported in a predetermined position in the main apparatus, wherein the optical beam scanning device scans the surface of the scanning target in a predetermined scanning direction with the optical beam irradiated from the light source, wherein the support member is a plate disposed respectively on a front side and a back side of the main apparatus, provided with first and second supported portions that are supported by a frame of the main apparatus at two locations in a direction perpendicular to the scanning direction in a plane parallel to the deflection plane, and wherein at least one of the supported portions is supported by the frame of the main apparatus such that the supported portion is movable in the direction perpendicular to the scanning direction in the plane parallel to the deflection plane.