Patent ID: 7830576

Claim:
A scanning optical apparatus comprising: a first rotatable polygonal mirror driven to deflect a first laser beam emitted from a first light source such that the first laser beam scans a first member to be scanned; a second rotatable polygonal mirror driven to deflect a second laser beam emitted from a second light source such that the second laser beam scans a second member to be scanned; a plurality of optical members configured to guide the first laser beam to the first member to be scanned and to guide the second laser beam to the second member to be scanned; a housing on which the first rotatable polygonal mirror, the second rotatable polygonal mirror, and the plurality of optical members are disposed; a vibration detecting unit configured to detect vibration of at least one of the optical members while the first rotatable polygonal mirror and the second rotatable polygonal mirror are driven; and a phase control unit configured to control a phase relation between the first rotatable polygonal mirror and the second rotatable polygonal mirror on the basis of an output of the vibration detecting unit such that the vibration of the optical member detected by the vibration detecting unit is reduced.