Patent ID: 7990406

Claim:
A multi-beam scanning device for focusing deflected light beams onto an object to be scanned, comprising: a light source unit rotatable about an optical axis, the light source unit including a plurality of light sources configured to emit light beams and a plurality of coupling lenses disposed corresponding to the light sources; a deflector configured to deflect the light beams emitted from the plurality of the light sources and passed through the plurality of the coupling lenses; a pitch adjustment device configured to move the light source unit in a first direction around the optical axis to adjust a beam pitch; a conical-shape compression-torsion coil spring configured to urge the light source unit in a second direction opposite the first direction around the optical axis as well as in the optical axis direction; and an error detector configured to detect an error in beam pitch adjustment performed by the pitch adjustment device, wherein, when the error detector detects the error in the beam pitch adjustment, the light source unit is returned to a position prior to detection of the error and inhibits subsequent beam pitch adjustment.