| 摘要 |
PURPOSE:To position a displacement optical device with a high precision and to prevent the magnification error and the out-of-focus, by making the operation direction for determination of a reference position equal to that for stopping in a target position to prevent the error due to the play of a mechanical system. CONSTITUTION:Mobile materials 20 and 30 which change positions of a lens 4 and mirrors 2a and 2c of an optical system are driven by stepping motors 21 and 31. One mobile material 30 is controlled by a wire 33 wound around pulleys 32a and 32b to vary positions of an object 3' to be photographed and a photosensitive drum 5 along the optical axis of a light source 4 in accordance with magnifications. Position detectors 24 and 34 are arranged in driving parts of mobile materials 20 and 30, and respective reference stop positions are determined by detectors 24 and 34. When mobile materials 20 and 30 are placed on one side of reference positions, motors 21 and 31 are rotated in one direction, and motors 21 and 31 are stopped when mobile materials 20 and 30 pass from one side to the other. When mobile materials are placed on the other side, motors 21 and 31 are rotated in the other direction once and are reversed when mobile materials pass through reference positions, and motors 21 and 31 are stopped when they pass reference positions. |
