Optical beam scanning device, optical beam scanning method

Abstract

There is provided a technique in which in an optical beam scanning device, optical characteristics can be suitably corrected according to a change in environmental temperature. The optical beam scanning device is configured to shape a divergent light from a light source into a light flux having a specified sectional shape by a pre-deflection optical system and to guide the light flux, which is shaped by the pre-deflection optical systemand is deflected and scanned in a main scanning direction by a rotation deflector, to a photosensitive surface of each of plural photosensitive bodies by a post-deflection optical system A, the pre-deflection optical systemincludes a first optical element which is an optical element having a negative power and in which a main light beam of the light flux guided in the pre-deflection optical systempasses along an optical axis of the optical element, and the post-deflection optical system A includes at least one second optical element which is an optical element including a diffraction grating formed on at least one of a light flux incident surface and a light flux outgoing surface and in which main light beams of light fluxes to be guided to the respective plural photosensitive bodies are incident on incident positions different from each other in a sub-scanning direction orthogonal to the main scanning direction.