Browse Prior Art Database

Original Publication Date: 1987-Oct-31
Included in the Prior Art Database: 2004-Apr-04

Publishing Venue

Xerox Disclosure Journal


A sheet feeder for a copier for the sequential separation and feeding of individual sheets from a stack of sheets with an impact type sheet feeder with flexible frictional flapper blades, a preprogrammed drive for automatically moving the sheet stacking tray towards or away from the sheet feeder, a reference stop automatically limiting the movement of the top of the stack relative to the feeder, and a programmed positioning mode for automatically slightly lowering the tray into an optimum feeding position in which the top of the stack is maintained at a substantially constant level position relative to the feeder, closely adjacent, but slightly spaced below, the limit position, and automatically programmed repositioning to maintain the optimum feeding position and to compensate for the reduction in the height of the stack as sheets are fed, and to provide improved double sheet feed prevention by cycling the tray though small up and down movements coordinated with the feeding of sheets from the stack, for moving the fed sheet into and out of engagement with retard members. Retarding is further assisted by angled take-way rollers deflecting the trail end of the fed sheet down against the next sheet. There is provided a plural mode stack repositioning system for automatically repositioning the top sheet of the stack of sheets into an optimum feeding position relative to the impact sheet feeder, which optimum feeding position is closely adjacent to, but slightly spaced below, a maximum limit position of the top of the stack. This stack re ositioning system further