| 摘要 |
PURPOSE:To simplify a magnification fine adjustment of a continuous variable power exposing scanning optical system by dividing a fixed cam for prescribing a moving extent of a mirror which moves in accordance with a movement of an image forming lens, into plural pieces, so that each position can be finely adjusted independently. CONSTITUTION:In case of setting an optical system to some magnification, a lens mechanism body 14 is moved, a pulley 16 is rotated by a cam follower 17 which slide-contacts to a fixed cam, and by driving of a cable 25 whose one end is fixed to the pulley 16, a mirror is moved in order to change an optical path length to a lens. According to this constitution, the fixed cam is divided into 29, 30, respectively, each of them can be rotated mutually by a hinge 31, screw shafts 34, 35 are installed to pins 32, 33 provided on the cam concerned, and the respective positions of each part 29, 30 of the divided cams can be finely adjusted independently by female screws 36, 37 engaged to the shaft concerned.
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