| 摘要 |
PURPOSE:To make a field angle large, as well while correcting surface inclination by arranging a toric lens for surface inclination correction which is nearly concentric concerning to a scanning surface and has low power in the vicinity of a spherical lens group. CONSTITUTION:The light beam which is emitted by a semiconductor laser 1 is collimated by a collimator lens 2 into nearly parallel light, which is made uniform in size by an aperture stop 3 and made incident on a cylindrical lens 4. The light beam is held parallel as it is concerning to the scanning surface and image-formed concerning to a subscanning surface to be made incident on a rotary polygon mirror 5 and the rotary polygon mirror is rotated at high- speed at the uniform speed as shown by an arrow and the incident light beam is reflected and deflected at the high speed to make a scan. The deflected scanning light beam passes through a 1st spherical lens 6 with negative power and a 2nd spherical lens 7 with positive power, and the toric lens 8 which is concentric is image-formed on a photosensitive drum 9. Consequently, curvature of field can be corrected while being balanced. |
