Patent attributes
An optical scanning device includes a light deflector that deflects light beams from a light source device and an optical scanning optical system that focuses the light beams deflected by the light deflector on a surface to be scanned, wherein the light beams are made incident on a deflective reflection surface of the light deflector at an angle in a sub-scanning direction with respect to a normal of the deflective reflection surface. The optical scanning optical system has at least one scanning focus lens, and at least one lens surface of the scanning focus lens is a surface, curvature in the sub-scanning direction of which changes according to an image height, and is a surface, curvature in the sub-scanning direction of which on a reference axis of the lens is zero or substantially zero, in order to effectively correct a scanning line curve and deterioration in a wavefront aberration.
