| 摘要 |
PURPOSE:To easily correct error in scanning position by a device wherein quantity of light of light beam on a face to be scanned of a support body is measured on the basis of a mark provided on the support body, a scanning position of a photosensitive body scanned by the light beam is detected, and a deviation with respect to a proper position is detected. CONSTITUTION:Light beam generated from a semiconductor laser 2 is applied on a reflective face of a polygon mirror 5 through a collimator lens 3 and a cylindrical lens 4, and the reflected beam is applied on a face to be scanned of a photosensitive body 1 through an ftheta lens 6. At this time, the light beam scans the face to be scanned of the photosensitive body 1 in the horizontal scanning direction. When the light beam scans a mark 12, a part of the light beam is reflected and injected in a light receive section 7. When a scanning position by the light beam is deviated from a proper scanning position of the photosensitive body 1, because of difference of quantity of receiving light, the deviation of the application position is measured as an error from an output difference of a light receive element, and vertical positions of the cylindrical lens 4 are corrected by a drive section 9 based on an error signal. |
