Patent ID: 6882453

Claim:
A scanning optical system for emitting a plurality of beams scanning in a main scanning direction, comprising: first and second light emitting devices each of which has a linear array of light emitting points; a collimator lens system that collimates each of the plurality of beams emitted from the plurality of light emitting points of said first and second light emitting devices; a first optical system that converges the plurality of beams emerged from said collimator lens system in an auxiliary scanning direction which is perpendicular to the main scanning direction; a deflector that deflects the plurality of beams emerged from said first optical system to scan in the main scanning direction; and a second optical system that converges the plurality of beams deflected by said deflector on a scan target surface to form a plurality of beam spots scanning in the main scanning direction, wherein said first optical system forms a plurality of line-like images in the vicinity of said deflector, wherein said first and second light emitting devices are positioned such that the linear array of light emitting points of each of said first and second light emitting devices is aligned in parallel with the auxiliary scanning direction and that the beam spots formed by the plurality of beams emitted by said first light emitting device and the beam spots formed by the plurality of beams emitted by said second light emitting device are alternately arranged on the scan target surface in the auxiliary scanning direction, wherein said first optical system includes; a first cylindrical lens having optical power in the auxiliary scanning direction; and a second cylindrical lens having optical power in the auxiliary scanning direction, wherein the first cylindrical lens is located on a light emitting device side and the second cylindrical lens is located on a deflector side.