Patent ID: 7012724

Claim:
An optical scanning device comprising: a light source unit having a plurality of light sources emitting multiple light beams; a scanning optical unit deflecting the multiple light beams from the light sources and focusing the deflected light beams so that each light beam forms a light spot on a scanned surface, the scanned surface being scanned by each light beam from the scanning optical unit; a temperature detection unit detecting a temperature of the scanning optical unit and its neighboring locations; and a temperature compensation unit adjusting each of a main-scanning-direction focal-point position related to each light beam, a sub-scanning-direction focal-point position related to each light beam, and a sub-scanning-direction beam pitch of the light beams on the scanned surface in accordance with a change in the temperature detected by the temperature detection unit, wherein the temperature compensation unit is configured to move the light source unit along its optical axis by an amount of movement corresponding to the temperature change to adjust the sub-scanning-direction beam pitch, and configured to move a plurality of corrector lenses along their optical axes by an amount of movement corresponding to the temperature change to adjust the main-scanning-direction focal-point position and the sub-scanning-direction focal-point position respectively, and wherein a beam pitch is defined by a spacing between two adjacent scanned lines formed by simultaneously scanning/deflecting two light beams from the light source unit.