Optical multi-beam scanning device and image forming apparatus

摘要

When a rear position on an excessive light emitting surface of an optical path synthesizing optical part for guiding a plurality of beams to one deflecting surface does not have a sufficient space, an optical multi-beam scanning device and an image forming apparatus of the present invention prevent excessive light from becoming stray light and exerting a bad effect on light sources and the other optical parts. The optical multi-beam scanning device of the present invention has a plurality of pre-deflection optical units, an optical path synthesizing member and an excessive light processing member. The pre-deflection optical units give predetermined properties to the light beams from the light sources. The optical path synthesizing member aligns optical paths of the light beams from all or some of the light sources in a horizontal scanning direction when the pre-deflection optical units give the predetermined properties to the light beams or while giving them to the light beams. The excessive light processing member processes excessive light emitted from an excessive light emitting surface which is not an incident surface nor an emitting surface of the optical path synthesizing member. The excessive light processing member has a multi-stage taper constitution with a plurality of taper surface having different tilt angles, an absorbing surface roughly parallel with the excessive light emitting surface for absorbing the excessive light emitted from the excessive light emitting surface, or repeated local patterns for dispersing the excessive light emitted from the excessive light emitting surface.