Patent ID: 7298537

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 incident beams in a most peripheral part in an effective write width are inclined in a same direction in a deflection surface of revolution with respect to a normal on a surface of a scanning lens close to the deflector, a scanning lens closest to the deflector has a meniscus shape with a concave facing the deflector side in the horizontal scanning direction, a surface close to the deflector, of the scanning lens closest to the deflector, has a negative power in the vertical scanning direction, and is 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 the surface close to the deflector of a scanning lens farthest from the deflector has a positive power in the vertical scanning direction.