Optical scanning device, method of adjusting the same, and image forming apparatus

摘要

A coupling optical system couples a light beam emitted from a light source that includes a two-dimensional array of light-emitting elements, including a first optical element having a positive power and a second optical element that has a negative power and receives the light beam passed through the first optical element. An incident surface and an output surface of the second optical element are concave. An absolute value of a paraxial curvature radius of the incident surface is larger than that of the output surface. A scanning optical system focuses the light beam that passed through the coupling optical system and deflected by a deflector on the target surface.