Patent ID: 7528858

Claim:
An imager comprising: a photosensitive surface; a light source which produces at least one scanning light beam; a deflector, arranged to deflect the at least one scanning light beam onto the photosensitive surface; a sensor which measures the orientation of the deflector; a controller operative to determine a placement error of the at least one scanning beam on the photosensitive surface, responsive to the orientation measurement by the sensor; and responsive to the displacement error, an actuator arranged to change the direction of deflection of the at least one light beam by the deflector, wherein: the sensor is an optical sensor configured to measure the orientation of the deflector substantially at a null in a vibrational mode of the deflector; and the sensor comprises: a second light source which produces a second light beam; a second deflector, fixed to the deflector or a support of the deflector, which deflects the second light beam; and an optical position sensor which measures a position of the deflected second light beam.