Browse Prior Art Database

VACUUM CORRUGATION FEEDER IMPROVEMENT

IP.com Disclosure Number: IPCOM000025245D
Original Publication Date: 1984-Apr-30
Included in the Prior Art Database: 2004-Apr-04
Document File: 2 page(s) / 94K

Publishing Venue

Xerox Disclosure Journal

Abstract

Some bottom vacuum corrugation feeders employ different modes when the feed tray contains 50 sheets. When the tray holds a sufficient number of sheets, the weight of the sheet stack causes air knife induced pressure between sheets 1 and 2 to rise and inflate a pocket between the sheets. When there are only a few sheets in the tray, the maximum stagnation pressure between sheets 1 and 2 is so low that the Bernoulli phenomena (low pressure as a result of increased air velocity at constrictions) can reduce the pressure between sheets 1 and 2 below the pressure between sheets 2 and 3. This results in holding sheets 1 and 2 in fluttering proximity with the air drag on sheet 2 restraining its motion. As additional sheets are added to the tray, the drag between sheets 1 and 2 is reduced. Addition of still more sheets raises the stagnation pressure sufficiently to overcome the Bernoulli action and thus greatly improves sheets 1 and 2 separation. The intermediate condition, just before pocket inflation, is believed to be the cause of "transition mode" multi-feeds in some feeders.

This text was extracted from a PDF file.
At least one non-text object (such as an image or picture) has been suppressed.
This is the abbreviated version, containing approximately 56% of the total text.

Page 1 of 2

XEROX DISCLOSURE JOURNAL

VACUUM CORRUGATION FEEDER IMPROVEMENT
Morton Silverberg

Proposed Classification
U.S. Cl. 271/105 Int. CI. B65h 3/46

Some bottom vacuum corrugation feeders employ different modes when the feed tray contains 50 sheets. When the tray holds a sufficient number of sheets, the weight of the sheet stack causes air knife induced pressure between sheets 1 and 2 to rise and inflate a pocket between the sheets. When there are only a few sheets in the tray, the maximum stagnation pressure between sheets 1 and 2 is so low that the Bernoulli phenomena (low pressure as a result of increased air velocity at constrictions) can reduce the pressure between sheets 1 and 2 below the pressure between sheets 2 and 3. This results in holding sheets 1 and 2 in fluttering proximity with the air drag on sheet 2 restraining its motion. As additional sheets are added to the tray, the drag between sheets 1 and 2 is reduced. Addition of still more sheets raises the stagnation pressure sufficiently to overcome the Bernoulli action and thus greatly improves sheets 1 and 2 separation. The intermediate condition, just before pocket inflation, is believed to be the cause of "transition mode" multi-feeds in some feeders.

A number of different solutions are possible for overcoming this "transition mode" multi-feeding and forcing a separation between sheets 1 and 2. For example, in a non-recirculating document handler or duplex tray application, the simplest solu- tion is to employ a weighted or spring-loaded cover plate which applies a sufficient normal load to shift the feeder operation into the pocket forming mode. The cover plate also inhibits blow-away so that high air knife pressures can be used. Another solution is to place substantially vertical air jets which apply normal forces at appropriate locations along the sides and rear portions of the...