Patent ID: 8089675

Claim:
An optical beam scanning apparatus comprising: a light source configured to emit one or plural luminous fluxes; a pre-deflection optical system configured to form the luminous fluxes emitted from the light source to image the luminous fluxes as a line image in a direction corresponding to a main scanning direction; a light deflecting device configured to scan the luminous fluxes against a scanning object in the main scanning direction; and a post-deflection optical system configured to at least include one or plural first optical elements which act on the luminous fluxes for all color components, plural second optical elements which respectively act on the luminous fluxes for each of color components, plural reflection mirrors which are respectively provided on a downstream side of the second optical elements in plural optical paths for all colors except for black and reflect luminous fluxes emitted from the second optical elements, and a position adjusting mechanism which adjusts positions of the reflection mirrors, the post-deflection optical system images the luminous fluxes scanned by the light deflecting device on the scanning object, the optical path for black being a reference for adjusting parallelism of a scanning line of each of optical paths in which the second optical elements are included.