Patent ID: 8363297

Claim:
An optical scanning device comprising: a light source unit having a light emitting section that emits a light beam; a light source drive unit configured to modulation drive the light source unit; a deflection unit configured to deflect the light beam emitted from the light source unit and scan in a main scanning area; a scanning image optical system having an optical axis and configured to guide the light beam from the deflection unit onto a target scanning surface; and a light beam detection unit having one or more detection surfaces to detect the light beam from the deflection unit, wherein the light source drive unit is configured to control an amount of light emission of the light source unit, wherein the deflection unit is configured to deflect the light beam so that a maximum deflection angle of a reflection surface of the deflection unit relative to the optical axis is greater than an incident angle of the light beam emitted from the light source unit to the reflection surface of the deflection unit relative to the optical axis, and wherein the light source drive unit is configured to control timings and a time period of a light emission amount control period where the light source unit is forcibly turned off by measuring a change of an deflection angle of the deflection unit based on a detection signal from the light beam detection unit, the light emission control period including a timing corresponding to an angle where the light beam reflected by the deflection unit returns to the light source unit.