Optical scanning device and image forming apparatus

摘要

An optical scanning device includes a light source that emits a laser beam, a deflector that deflects the emitted laser beam, a scanning lens that causes the deflected laser beam to scan a surface of a photosensitive body at a uniform velocity, a reflector having a reflective surface that reflects the deflected laser beam toward the photosensitive body among the laser beams that have passed through the scanning lens, and a synchronization sensor that receives the laser beam from the reflector and outputs a detection signal. The reflector is set so that a scanning speed in a main scanning direction of the laser beam on a light-receiving surface of the synchronization sensor becomes greater than a value obtained by dividing a scanning distance of the laser beam in the main scanning direction on the light-receiving surface of the synchronization sensor by a response delay time of the synchronization sensor.

主权项

1. An optical scanning device, comprising:
a light source unit which emits a laser beam; a deflector which reflects and deflects the laser beam emitted from the light source unit; a scanning lens which causes the laser beam deflected by the deflector to scan a surface of a photosensitive body at a uniform velocity; a reflector having, on its surface, a reflective surface which reflects the laser beam deflected toward the outside of the photosensitive body among the laser beams that have passed through the scanning lens; and a synchronization sensor with a light receiving surface that receives the laser beam reflected by the reflector and outputs a detection signal representing the reception of the laser beam, the synchronization sensor outputting the detection signal after a lapse of a response delay time, starting from reception of the laser beam, the response delay time being unique to the synchronization sensor and corresponding to a predetermined amount of light of the received laser beam being accumulated; wherein the reflective surface of the reflector has an optical power to reduce a scanning distance of the laser beam on the light-receiving surface of the synchronization sensor in a main scanning direction, which is a scanning direction of the laser beam on the light-receiving surface of the synchronization sensor, and wherein the optical power is selected to reduce the scanning distance of the laser beam sufficiently for a scanning speed of the laser beam in the main scanning direction to become greater than a value obtained by dividing the scanning distance by the response delay time of the synchronization sensor in order to complete, within the response delay time, entrance of the laser beam reflected by the reflective surface to the synchronization sensor.