Patent ID: 7916375

Claim:
A method for adjusting an optical scanning apparatus including a light source having a light-emitting point; a light-beam converting unit configured to convert a state of a light beam emitted from the light-emitting point of the light source into another state; a deflecting unit configured to deflect and scan the light beam emitted from the light-beam converting unit, the deflecting unit including a resonant deflecting element having a single deflecting surface that reciprocates around an axis; and an imaging optical unit configured to cause the light beam deflected and scanned by the deflecting surface of the deflecting unit to form an image on a surface to be scanned, the method comprising: detecting the light beam emitted from the light source, deflected by the deflecting surface of the deflecting unit, and transmitted through the imaging optical unit with a first detector; and adjusting a distance between the light-emitting point of the light source and the light-beam converting unit with an adjusting unit based on information obtained by the first detector; wherein the following condition is satisfied: 0.001<2 k/ ( Rm+ 2 k )<0.02 where k is a scanning angular speed of a spot on the surface to be scanned and Rm is a radius of curvature obtained when a warped shape of the deflecting surface of the resonant deflecting element in a main-scanning direction is fitted to an arc shape by the least squares method.