| 摘要 |
A scanning unit in an image forming apparatus includes a light source, a coupling lens, an aperture, an image forming lens, and a polygon mirror. The light source includes a plurality of surface-emitting lasers. The coupling lens, the aperture, and the image forming lens are arranged on the optical path of light beams emitted by the light source. The polygon mirror deflects light beams of an image formed by the coupling lens towards a photosensitive drum for scanning. The focal length of the image forming lens in a sub-scanning direction is set to be equal to or smaller than an optical path length between the image forming lens and the aperture. |
