Browse Prior Art Database

Original Publication Date: 1992-Dec-31
Included in the Prior Art Database: 2004-Apr-06

Publishing Venue

Xerox Disclosure Journal


As illustrated in U.S. Patent No. 4,480,824 by Acquaviva, it is commonly known to detect mis-stacking or jamming in a sheet stack of an automatic document handler. Similarly, it is necessary to detect jamming of copy sheets at the output stack of a reprographic system. As illustrated in the figure, some reprographic systems utilize a disc or wheel, 12, to deliver sheets to an output stack, 14, in an inverted fashion. Unfortunately, during the inversion and stacking operation the sheets are not bound by constraints such as paper baffles. Hence, it is difficult to utilize conventional paper sensors like switches or optical channel sensors to detect jammed sheets during this time. Moreover, in a stacker that is required to stack sheets of varying sizes the problem is further compounded, thereby requiring additional sensors or a compromise in the integrity of the stacking subsystem.