Scanning and imaging lens, optical scanning device and image forming apparatus

摘要

A scanning and imaging lens condensing a light flux deflected by a deflector onto a surface to be scanned as a beam spot, has a plurality of lenses. 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 the 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 the lens on the side of surface to be scanned is a non-arc shape. The 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.