Patent ID: 7149009

Claim:
A scanning optical apparatus comprising: light source means, having a plurality of light emitting points, for emitting a plurality of beams; deflecting means for deflecting the plurality of beams; incidence optical means through which the plurality of beams emitted from said light source means are directed to said deflecting means; scanning optical means for directing the plurality of beams deflected by said deflecting means onto a surface to be scanned; and synchronism detecting means for detecting a part of the plurality of beams incident on said surface to be scanned, wherein a timing of a scanning starting position of the plurality of beams incident on the surface to be scanned is adjusted by using a synchronized signal obtained by said synchronism detecting means; wherein said synchronism detecting means comprises a synchronism detecting device; wherein a light source including one or more of the plurality of light emitting points of said light source means is provided on a substrate, said synchronism detecting means further comprising an optical element disposed on a light incidence side of said synchronism detecting device, and wherein said optical element is designed to be rotated in synchronism with said substrate when said substrate is rotated.