| 摘要 |
PURPOSE:To locate a slit scanning starting position and a slit exposure starting positon always at fixed positions respectively independently of the magnification of projection, to improve maneuverability, to simplify the mechanism, and to fix the timing of work by displacing an optical system so that the scanning starting position of an original and the slit exposure starting position of a photoreceptor are always set up on fixed positions respectively independently of the magnification of projection. CONSTITUTION:When the magnification of projection is ''1'', an image formation lens 1 is located on the position shown by the solid line, the 1st scanning mirror 20 is moved from a starting position 201 to a position 202 and the 2nd scanning mirror 30 is moved from a position 301 to a position 302. A slit scanning starting position O1 forms its image on a slit exposure starting position P1 on the photoreceptor 40 and a slit exposure ending position O2 forms its image on a position P2. In order to change the magnification of projection to a reduced magnification (m), the image formation lens 1 is displaced up to the position 1' shown by the dotted line and the 1st and 2nd scanning mirrors 20, 30 are displaced to the positions shown by codes 203, 303 respectively. Thus, the slit exposure starting position P1 is located in a fixed position independently of the magnification of projection. |
