Browse Prior Art Database

BOTTOM ACTIVE RETARD FEEDER

IP.com Disclosure Number: IPCOM000026733D
Original Publication Date: 1993-Jun-30
Included in the Prior Art Database: 2004-Apr-06
Document File: 4 page(s) / 146K

Publishing Venue

Xerox Disclosure Journal

Abstract

Proposed is a bottom active retard paper feeder consisting of a nudger roll, a retard roll, a bail bar, and a slip clutch. As shown in the illustration, paper is driven from the bottom of a stack of paper 34, by virtue of the nudger roll 20 rotating in the direction of arrow 21, into the nip formed by feed roll 26 and retard roll 22. The normal force applied to the nudger roll 20 is provided by a bail bar 24. The feed roll 26 is driven in the paper feed direction indicated by arrow 27, while the retard roll 22 is driven actively in the reverse direction indicated by arrow 23, through a slip clutch (not shown) with a specified torque. The feedhetard mechanism drives multiple sheets 28 and 29 backward when more than one sheet of paper enters the nip allowing only the bottom most sheet 30 to pass through the nip. The ability of this device to perform this function lies in the frictional interface difference between paper to paper and paper to elastomer or retard roll 22.

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Page 1 of 4

XEROX DISCLOSURE JOURNAL

BOTTOM ACTIVE RETARD FEEDER
William D. Milillo

Proposed Classification

U.S. C1.355/309 Int. C1. G03g 21/00

22

20 26

XEROX DISCLOSURE JOURNAL - Vol. 18, No. 3 May/June 1993 277

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BOTTOM ACTIVE RETARD FEEDER (Cont'd)

Proposed is a bottom active retard paper feeder consisting of a nudger roll, a retard roll, a bail bar, and a slip clutch. As shown in the illustration, paper is driven from the bottom of a stack of paper 34, by virtue of the nudger roll 20 rotating in the direction of arrow 21, into the nip formed by feed roll 26 and retard roll 22. The normal force applied to the nudger roll 20 is provided by a bail bar 24. The feed roll 26 is driven in the paper feed direction indicated by arrow 27, while the retard roll 22 is driven actively in the reverse direction indicated by arrow 23, through a slip clutch (not shown) with a specified torque. The feedhetard mechanism drives multiple sheets 28 and 29 backward when more than one sheet of paper enters the nip allowing only the bottom most sheet 30 to pass through the nip. The ability of this device to perform this function lies in the frictional interface difference between paper to paper and paper to elastomer or retard roll 22.

When the feeder is in its steady state feed mode, the combination of two different frictional interfaces cause the retard roll 22 to assume an equilibrium position relative to the slip clutch torque. This equilibrium position will allow one sheet to pass even though the feed roll 26 and retard roll 22 materials are the same. The retard roll 22 will stay stalled until such time when more than one sheet attempts to enter the feedlretard nip. At the time, the frictional interfaces at the nip change in a direction to trigger the retard roll 22 to drive in the reverse direction clearing the nip of multiple sheets. Once this is accomplished, the retard roll 22 assumes its normal stationary position. The ability of the feeder to mechanically sense multiple sheets in the feearetard nip and thereby respond to actively drive the multiple sheets backwards makes this feeder an extremely powerful separator.

REFERENCES:

US. Patent No. 3,614,089 to VanAuken et al. discloses an automatic feed mechanism for feeding individual sheets one at a time from a stack of sheet...