| 摘要 |
PURPOSE:To keep a process speed except exposure constant, and to elevate copying efficiency, by making an endless belt photosensitive body have a sag, and keeping a belt speed of the return side constant, irrespective of a belt speed of the exposed side. CONSTITUTION:The first section 10(1) between a capstan roll 17c and 17b of an endless belt photosensitive body 10 is driven at a variable speed in the left and right directions by a motor 11b, the second section 10(2) reaching a capstan roll 17a from a guide roll 21a is rotated at a constant speed by a motor 11a, and the belt is made to have a sag which has multiplied this speed difference by the exposure time. The photosensitive body 10 stops at the time of unmagnification, is moved in the reverse direction against an optical system at the time of reduction, is moved in the same direction at the time of magnification, and a sag in that case is absorbed by chambers 18a, 18b. A speed of the return side, however, is always constant, a device except exposure holds a constant speed, its stop, etc. are not required, and the copying efficiency can be elevated. |
