| 摘要 |
PROBLEM TO BE SOLVED: To reduce the manufacture cost by the relaxation of the precision of an optical element and assembly precision by easily correcting a shift in the image formation position of curvature of field in both a horizontal and a vertical scanning direction. SOLUTION: The divergent luminous flux emitted by a light source 10 after being coupled by a coupling lens 12 with desired luminous flux is deflected by an optical deflector 16 at an equal angular velocity and the deflected luminous flux is converged by an image forming lens 18 to form a light spot on the scanned surface 20 of a photosensitive body. Then a parallel flat plate 22 for properly adjusting the focus of the light spot converged on the scanned surface 20 in the horizontal and vertical scanning directions is installed between the coupling lens 12 and optical deflector 16. |
