Patent attributes
An optical scanning device includes a coupling optical system, a light source including a plurality of light emitting units for emitting light beams, and a deflector including a deflecting surface for deflecting the light beams. The coupling optical system is arranged on an optical path between the light source and the deflector so that the light beams enter the deflector at an angle with respect to a normal direction of the deflecting surface in a sub-scanning direction. The light emitting units are arranged two-dimensionally, and a distance between two light emitting units at opposite ends in a main scanning direction is smaller than a distance between two light emitting units at opposite ends in the sub-scanning direction.