| 摘要 |
PURPOSE:To keep the sufficient angular margin of the stopping position of a variable power cam and to make a mirror unit act smoothly by providing the variable power cam formed by making cam shapes respectively corresponding to the paper sizes such as an AB system and an inch system correspond to the surface and the back surface of the cam. CONSTITUTION:The cam shape for the AB system is formed corresponding to the surface 12a side of the variable power cam 12 and within the angular range of about 180 deg. as in the conventional manner, and the cam shape for the inch system is formed corresponding to the back surface 12b side and within the angular range of about 180 deg. in the same way, so that both surfaces are properly used in accordance with the paper size. Since the cam shape for each paper size is formed corresponding to the surface or the back face of the cam 12, it becomes the cam shape having the four-stage stopping positions. Then, the angular margin of each stopping position is made large and the linking part of each stage is made smooth, so that the mirror unit 15 is moved smoothly. |
