Patent ID: 7692678
Filing Date: 2010-04-06
Classification: G02B,H01S,H04N

Abstract:
1. A laser light control device for an image forming apparatus including a semiconductor laser and a polygon mirror that deflects and scans laser light emitted from the semiconductor laser to form a latent image on a photosensitive drum, the laser light control device controlling an emission light quantity of the semiconductor laser, the laser light control device comprising: a detecting unit configured to detect the laser light at a non-image formation region on the photosensitive drum and output a signal based on the detection result; a signal generating unit configured to generate a first signal and a second signal based on the signal output from said detecting unit; a control unit configured to perform control of a write start position of the laser light in a main scanning direction based on the first signal and control of the emission light quantity of the laser light based on the second signal; and an optical element including a first configuration so as to exert a refractive power of collecting the laser light, deflected and scanned by the polygon mirror, on the detecting unit for the purpose of allowing the signal generating unit to generate the first signal, and including a second configuration so as to make the laser light, deflected and scanned by the polygon mirror, substantially stationery on said detecting unit for the purpose of controlling the emission light quantity of the laser light, a first configuration-part of the optical element being located at a portion upstream of a second configuration-part of the optical element with respect to a direction of the laser light scanning said detecting unit.