| 摘要 |
PURPOSE:To improve the print quality of a laser printer by correcting the beam waist position of laser light by an electrooptic lens which is brought under feedback control according to a shift in the beam waist position. CONSTITUTION:An image formation optical system which includes the electrooptic lens 4 and an optical deflector 6 are arranged on the optical path extending from the laser light source 2 to the scanned surface 11 and an image information position detecting means 13 for detecting the beam waist position of the laser light which is emitted by the laser light source and converged is provided; and a DC voltage corresponding to its detected value is applied to the electrooptic lens to correct the beam waist position every time a scan is made, thereby eliminating the influence of temperature variation, etc., upon the print quality. Further, the scanning image formation position detecting means detects the quantity of a shift in the beam waist position during the scanning of the laser light and a high frequency voltage corresponding to its detected value is applied to the electrooptic lens by a scanning position uniforming means to correct the shift in the beam waist position during the scanning, thereby compensating aberrations such as the curvature of field, etc., during the scanning. |
