Patent ID: 6243126
Filing Date: 2001-06-05
Classification: B41J,G02B,H04N

Abstract:
An image forming apparatus for scanning an image carrier with a laser beam emitted by a semiconductor laser, comprising:an adjuster for adjusting a position of the laser beam in a direction perpendicular to the scanning direction;an optical unit for focusing onto one point part of the laser beam immediately before it scans the image carrier;a photoelectric converter arranged at a position where the laser beam is brought to a focus by said optical unit; andcontrol means for controlling said adjuster in accordance with an output from said photoelectric converter,wherein said optical unit comprises a half-mirror for deflecting part of the laser beam in a direction different from a traveling direction of the laser beam, and a condenser for focusing the laser beam deflected by said half-mirror onto said photoelectric converter,wherein said condenser comprises a plurality of polarizers laid out in the scanning direction, andwherein said image forming apparatus further comprises:detection means for detecting distortion of a quantity of laser beam guided from said condenser to said photoelectric converter; anddetermination means for determining based on a detection result of said detection means whether a scanning speed of the laser beam is proper.