Patent ID: 7253827

Claim:
A multi-beam optical scanning apparatus comprising: light source means including a plurality of radiation points disposed with being spaced from each other in a main scanning direction; and deflecting means for deflecting a plurality of light beams radiated from said plurality of radiation points toward a surface to be scanned; wherein where a first radiation point is a radiation point for radiating the light beam, out of the plurality of light beams emitted from said plurality of radiation points, which reaches the farthest location from a center of a deflecting facet of said deflecting means in the main scanning direction, a second radiation point is a radiation point for radiating another light beam, and an upstream-side external angular range is a range which lies in an angular range over which the light beam can be deflected by said deflecting means, and which exists on an upstream side in a rotational direction of said deflecting means relative to an effective scanning angular range at the time when the light beam is deflected toward an effective scanning range on the surface to be scanned, control is performed such that the light beam from said second radiation point can be radiated prior to the light beam from said first radiation point in the upstream-side external angular range.