| 摘要 |
In an electrophotographic copying apparatus, the document stack to be fed is curved when it rests on a fixed curved stack-holding tray. The document stack is lifted by a pair of lifting blades having the curvature of the stack which move horizontally relative to the ends of the stack to move in and out beneath the sides of the stack, and thereafter move vertically to lift the entire stack out of the path of the returning copy. A vacuum belt arrangement is provided for moving successive documents from the top of the stack into the electrophotographic copying machine. The document loops through the machine and returns at a lower level, aligned with an opening beneath the bottom of the stack. Moving belts running beneath the stack carry the returning document into alignment under the stack. Once the document is returned, the lifting blades move vertically downward and laterally outward, resting the remainder of the document stack on the returned document, making it a part of the stack; when the lifting blades again perform their cyclic motion, they again move under the bottom edges of the stack and lift the stack, including the returned document. The blades are carried on vertical side supports. When a sheet is being returned to the stack, at least one vertical lifting blade side support is held a short distance from the side of the stack. When the stack is to be lowered, the vertical support is first moved in toward the stack so that the bottom, returned sheet is aligned with the rest of the stack. The stack is then lowered onto the returned sheet. Knife edge elements are provided movable between the belts which return the sheets to the bottom of the stack. These knife edges are normally lowered; they rise between the belts to lift the returned sheet up under the bottom of the stack.
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