| 摘要 |
<p>A xerographic copier having a plurality of copy sheet supply bins wherein the bin paper stacks not currently in use are lowered to an intermediate position until such later time whereat a different stack is selected for use. A sensing switch senses the top of each non-used stack and bidirectionally maintains the stack at its intermediate level. Swelling of the paper stack, due to humidity and the like, causes the stack's elevator platform to lower under the control of the sensing switch. This sensing switch also senses the top of the stack when the stack is in use, and bidirectionally maintains the top of this stack at a higher sheet feed position. These two sensing functions are provided by a single pivoted member which engages the top sheet of the stack. This pivoted member controls a switch means. The selection of a stack causes a change in the physical position of the pivot and the switch means for this stack. This positional change causes the top sheet of this stack to be elevated to the sheet feed position.</p> |
