| 摘要 |
<P>PROBLEM TO BE SOLVED: To provide an optical scanner, in which the detection of the positional deviation of the beam spot position of a laser beam is performed with high accuracy, and a high speed color picture is obtained with high quality, to provide an image forming apparatus, and to provide a method of correcting vertical scanning position. <P>SOLUTION: A liquid crystal deflecting element 19 and a laser light detector 20 are provided in the path of the laser light. The liquid crystal deflecting element 19 is provided in between a light source unit 18 and a polygon mirror 12, and the laser light detector 20 is provided, in a region which is located upstream of the main scanning direction and outside the end part of a picture region. The laser light detector 20 detects the vertical scanning position of the laser light and the laser light is deflected, by driving the liquid crystal deflecting element 19 so as to correct the deviations of the vertical scanning position from the reference vertical scanning position. <P>COPYRIGHT: (C)2007,JPO&INPIT |
