| 摘要 |
PROBLEM TO BE SOLVED: To obtain an optical scanning that has no deviation of scanning position, is good in image forming characteristic, and that can optically scan with a minute spot diameter, by attaching a cylindrical lens to an optical axis adjusting device moving the lens in a direction vertical to an optical axis and the generatix of the lens. SOLUTION: The light beam emitted from a light source 1 is made parallel beams by a collimating lens 2 to pass through the cylindrical lens 3 inserted for a plane tilt compensation to be deflectingly scanned with a rotary polygon mirror 4 and the beams are converged on a photosensitive body 6 with an f-theta lens 5. The variation between the height of the generatrix of the lens 3 and the height of optical axes of light beams due to the manufacturing error of the lens 3 and the manufacturing error of its holding base is adjusted by moving the lens 3 in the vertical direction with an optical axis adjusting device 17. Thus, the height of the generatrix of the lens 3 and the height of the light beams become the same and since the light beams advance toward the center part of the lens 5, a beam spot in which the deviation of scanning position is not present and the curvature of scanning line is not present also and whose diameter is minute and which is stabilized is obtained. |
