| 摘要 |
PURPOSE:To uniform the line pitch of a main scanning on a recording material by operating a moving means according to a position shift detected by a position shift detecting means, and providing a control means which performs control so that a light beam aligned with a reference line. CONSTITUTION:When a reflecting surface slants, the light beam does not pass on the reference line, but is deviated and moved. Consequently, the position shift can be detected from the degree of this deviation. The control means 16 outputs a signal to the moving means 44 according to the detected position shift to move a subscanning optical system 26. When the subscanning optical system 26 is moved, a light beam passing through the subscanning optical system 26 is moved in a subscanning direction in parallel, consequently, the light beam is aligned with the reference line. Consequently, the fitting of the optical system for surface tilt correction is facilitated, and the pitch of scanning track lines of light beams by the respective reflecting surfaces of a polygon mirror is uniformed. |
