| 摘要 |
PURPOSE:To shorten the time required for changin a magnification, to make a device small in size and inexpensive, an also to obtain easily sufficient accuracy by turning a rack frame by 180 degrees around the axis. CONSTITUTION:A ball 31 is engaged with an engaging hole 32 provided on a rack frame 25, by which the rack frame 25 is positioned, and an optical axis of a zoom lens 7 is matched accurately with a center axis 191 of an optical path 19. In case copying of unmagnification, namely, magnification 1 is executed, the zoom lens 7 makes a center point ''0'' conform with a middle point M, and in case magnified copying is executed, the rack frame 25 is set to a full line position, and the zoom lens 7 is moved to a position corresponding to the magnification by rotating a feed screw 22. Subsequently, in case reduced copying is executed, when the rack frame 25 is rotated around an axis 27, the zoom lens 7 occupies the position of the reduction side as shown by a chain line, and in accordance with necessity, a fine adjustment by a difference of the magnification may be executed. Especially, in case of executing the reduced copying of 1/m times after executing the magnified copying of (m) times (m>1), the rack frame 25 may be rotated by 180 degrees. |
