| 摘要 |
PURPOSE:To offer the optical scanner which is reduced in its occupation area and easily adjusted by forming a rotary polygon mirror so that a space is formed around its rotary shaft, and providing plural reflecting mirror surfaces which face inside surrounding the space. CONSTITUTION:In the optical canner 1, a laser beam LB which is projected by a laser unit 3 passes through a cylindrical lens 5 and travels to the recessed part bottom surface 9b of a polygon 9 in parallel and is reflected by 90 deg. on a mirror surface 9d to form an image on the surface of a photosensitive drum through an ftheta lens unit 11. Thus, the mirror surfaces 9d are provided on internal wall surfaces surrounding a recessed part 9a, in which the laser unit 3 and a cylindrical lens 5 are arranged, so an optical path is extended in the space of the polygon 9 in the direction of the rotary shaft. Consequently, all the optical systems need not be provided on the same plane unlike before and the occupation area of the device 1 is reducible. |
