Patent ID: 7164516

Claim:
An optical scanner comprising: a light source; an optical coupler that couples beams from the light source; an optical line image unit that forms a line image of the beams from the optical coupler, wherein the line image is longer in a horizontal scanning direction than in a vertical scanning direction; a deflector that deflection-scans the beams from the optical line image unit; and an optical scanning unit that includes a plurality of scanning lenses that guide the beams from the deflector to a surface to be scanned, wherein at least one scanning lens has a rotationally symmetric aspheric surface and a special toric surface in which a radius of curvature in a vertical scanning changes from an optical axis of the lens surface toward a periphery of the horizontal scanning direction, and a surface having an area with a largest angle of inclination in an effective range with respect to a surface perpendicular to the optical axis, among the surfaces of all scanning lenses, is the rotationally symmetric aspheric surface.