Laser beam scanning device, image forming apparatus, and laser beam detecting method by the laser beam scanning device

摘要

A laser beam scanning device is disclosed. The laser beam scanning device includes a diffraction optical element which forms a pattern of a diffraction image including two images extending in a direction corresponding to the sub scanning direction and one image extending in a direction inclined by θ (0θ90°) from the direction corresponding to the sub scanning direction by inputting a laser beam which is led to a surface of a photoconductor drum, and a light receiving element which receives the pattern of the diffraction image.