Patent ID: 6476955
Filing Date: 2002-11-05
Classification: G02B,H04N

Abstract:
A multi-beam scanning optical system comprising:incidence optical means for guiding a plurality of beams emitted from light source means having a plurality of light-emitting regions spaced apart from each other in a main scanning direction, to deflecting means; scanning optical means for focusing the plurality of beams deflected by the deflecting means, on a surface to be scanned, to form a plurality of scan lines; synchronism-detecting optical means for converging at least one of the plurality of beams deflected by the deflecting means on a slit surface and thereafter guiding the at least one of the plurality of beams to a synchronism detector, and controlling timing of a scan start position on the surface to be scanned for the plurality of beams by use of a signal from the synchronism detector; and correction means for correcting a dot shift per scan line on the surface to be scanned, which occurs because of a defocus amount &dgr;M1 in a main scanning section of the at least one of the plurality of beams guided to the synchronism detector and in a view from the slit surface.