Patent ID: 6448998
Filing Date: 2002-09-10
Classification: B41J,G02B

Abstract:
A scanning and imaging lens condensing a light flux deflected by a deflector onto a surface to be scanned as a beam spot, comprising a plurality of lenses, wherein:a shape in main scanning cross section of each of both surfaces of a lens on a side of deflector has a convex shape, and a shape in main scanning cross section of at least one surface of said lens on the side of deflector is a non-arc shape; a shape in main scanning cross section of a first surface of a lens on a side of surface to be scanned has a convex shape, and a shape in main scanning cross section of at least one surface of said lens on the side of surface to be scanned is a non-arc shape; said scanning and imaging lens has at least two special toroidal surfaces in each of which a curvature in sub-scanning cross section varies in main scanning direction; and each of said at least two special toroidal surfaces have no rotational symmetrical axis.