Patent ID: 8130434

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 for imaging the luminous fluxes scanned by the light deflecting device on the scanning object and 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, a first reflection mirror which is provided in an optical path between the first optical element and one of the second optical elements and reflects, on a most upstream side of optical paths between the first optical element and second optical elements, a luminous flux on a most downstream side or a most upstream side in a sub-scanning direction among the plural luminous fluxes acted on by the first optical element, and a second reflection mirror which is provided in an optical path between the first optical element and another second optical element and reflects, second from a most downstream side of the optical paths, the luminous flux on the most downstream side or the most upstream side in the sub-scanning direction among the plural luminous fluxes acted on by the first optical element.