Patent ID: 8520282

Claim:
An optical scanning apparatus comprising: a laser beam source configured to emit a laser beam; a deflector configured to deflect and scan the laser beam emitted from the laser beam source, the deflector including a deflecting portion that is operated to reciprocate in a first deflection direction and a second deflection direction opposed to the first deflection direction, thereby deflecting the laser beam emitted from the laser beam source, and a driver configured to operate the deflecting portion; and a detecting device configured to detect the laser beam deflected and scanned by the deflector, the detecting device including a light receiving sensor arranged to receive the laser beam deflected and scanned by the deflector, and a blocking portion which is disposed upstream of the light receiving sensor in a direction in which the laser beam enters the light receiving sensor and downstream of the light receiving sensor in the first deflection direction and which is arranged to block the laser beam so as to prevent the laser beam from entering the light receiving sensor, the blocking portion being provided with an edge, being able to prevent the laser beam deflected downstream of the edge in the first deflection direction from entering the light receiving sensor, and allowing the laser beam deflected upstream of the edge in the first deflection to enter the light receiving sensor; wherein during one cycle of the reciprocating operation of the deflecting portion, the detecting device detects a first timing at which the laser beam deflected and scanned in the first deflection direction by the deflector passes the edge, and a second timing at which the laser beam deflected and scanned in the second deflection direction by the deflector passes the edge, and a controller configured to control the operation of the deflecting portion, which is performed by the driver, based on the first and second timings detected by the detecting device.