Patent ID: 6961163

Claim:
A scanning optical system, comprising: a light source that emits a plurality of beams; a polygonal mirror that deflects the plurality of beams emitted by said light source to scan within a predetermined angular range; an imaging optical system that converges the plurality of beams on a plurality of surfaces to be scanned, respectively, wherein said imaging optical system includes a scanning lens and a plurality of compensation lenses located between said scanning lens and a plurality of surfaces to be scanned, the plurality of beams passing through said scanning lens, the plurality of beams passed through said scanning lens being incident on said plurality of compensation lenses, respectively, wherein each of said plurality of compensation lenses having an anamorphic surface, shapes of the anamorphic surfaces of said plurality of compensation lenses in a main scanning direction being substantially the same with respect to each other, wherein the anamorphic surface of each of said compensation lenses is asymmetrical with respect to a plane that is perpendicular to an auxiliary scanning direction and includes a center of the anamorphic surface.