| 摘要 |
PURPOSE:To prevent the generation of oscillations, etc. in the stage of starting and stopping by supporting a moving frame body having an optical system device by means of a pair of screw shafts and nut members at both ends thereof, and supporting a pair of screw shafts of high rigidity which receive the moving forces thereof surely. CONSTITUTION:A linear back and forth driving device 19 moves the lens 10 in a variable magnification optical system device 2 in a perpendicular direction B as a torsional axis direction, and scans in a scanning direction A as well via a scanning part 13 for copying. The device 19 has a pair of screw shafts 20, 21 which face the direction B and are mutually parallel and a driving shaft 22 of a horizontal direction, which shafts are fitted pivotally to a base plate 9 by means of bearings 23. A pair of the shafts 20, 21 have screw parts 201, 211, which are provided respectively with nut members 26, 27. The members 26, 27 are provided on both side surfaces of a moving frame body 28 having an optical system device disposed between the shafts 20 and 21 and prevent the generation of oscillations in the stage of starting and stopping. |
