Browse Prior Art Database

STACK CAVITY JAM DETECTION

IP.com Disclosure Number: IPCOM000026595D
Original Publication Date: 1992-Dec-31
Included in the Prior Art Database: 2004-Apr-06
Document File: 2 page(s) / 119K

Publishing Venue

Xerox Disclosure Journal

Abstract

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.

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Page 1 of 2

XEROX DISCLOSURE JOURNAL

STACK CAVITY JAM DETECTION Jose J. Soler
Paul D. Keller
Kenneth F. Blanchard
Richard F. Scarlata

Proposed Classification
U.S. C1.271/003.1 Int. C1. B65H 05/22

-34 14

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Page 2 of 2

STACK CAVITY JAM DETECTION(Cont'd)

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.

Accordingly, the present disclosure describes a jam sensing scheme which was developed for such a subsystem using optically reflective sensors to detect copy sheets as they pass by optically reflective sensors 20 and 22, and thereby identify key events during the stacking cycle. Moreover, depending on the sequence of the signals from sensors 20 and 22, certain fault conditions, or jams, may be detected automatically, allowing the copying operation to be completed without a loss of integrity in the output stack.

In normal operation, a sheet would arrive at the stacker in the direction indicated by arrow...