Patent ID: 7542187

Claim:
An image forming apparatus which forms an image by scanning a light beam in a main-scan direction of a photosensitive member, said apparatus comprising: an output unit configured to irradiate a light beam for exposing the photosensitive member; a deflection unit configured to deflect a light beam from said output unit to scan the photosensitive member in the main-scan direction; a light-receiving unit configured to detect the light beam deflected by said deflection unit; a computation unit configured to calculate difference information by using information of a detected time based on a timing at which the light beam is detected by said light-receiving unit; a control unit configured to drive said deflection unit by setting a parameter for controlling operation of said deflection unit based on the difference information; a prediction unit configured to predict a correction amount of a scan width in the main-scan direction in a next scan based on the difference information; a modulation unit configured to generate a driving signal for driving said output unit based on image data and the correction amount; and a driving unit configured to drive said output unit based on the driving signal.