Browse Prior Art Database

DOCUMENT HANDLER VACUUM ACTUATED MULTIFEED DETECTOR

IP.com Disclosure Number: IPCOM000026871D
Original Publication Date: 1994-Feb-28
Included in the Prior Art Database: 2004-Apr-06
Document File: 4 page(s) / 146K

Publishing Venue

Xerox Disclosure Journal

Abstract

All recirculating document handlers currently used on reprographic products occasionally feed two or more documents which do not separate properly, but pass through the paper path together as a single sheet, commonly referred to as a multifeed. In two sided copying or scanning, a multifeed can often be detected by counting sheets during feeding and then checking for equal first and second side counts. In single sided copying or scanning, multifeeds can be detected using a manual or mechanical precount. High volume electronic reprographic machines may be more sensitive to undetected multifed documents than are their light lens equivalent machines, because the electronic reprographic document handler only circulates the document set once, regardless of the number of prints desired. If a multifeed occurs, all prints will be defective Thus, job yield is strongly affected by undetected multifeeds.

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 54% of the total text.

Page 1 of 4

XEROX DISCLOSURE JOURNAL

DOCUMENT HANDLER VACUUM Proposed Classification ACTUATED MULTIFEED U.S. C1.355/316 DETECTOR Int. C1. G03g 21/00 Warren F. Brandkamp

XEROX DISCLOSURE JOURNAL - Vol. 19, No. 1 JanuaryFebruary 1994 63

[This page contains 1 picture or other non-text object]

Page 2 of 4

DOCUMENT HANDLER VACUUM ACTUATED MULTIFEED DETE CTOR(Cont'd)

All recirculating document handlers currently used on reprographic products occasionally feed two or more documents which do not separate properly, but pass through the paper path together as a single sheet, commonly referred to as a multifeed. In two sided copying or scanning, a multifeed can often be detected by counting sheets during feeding and then checking for equal first and second side counts. In single sided copying or scanning, multifeeds can be detected using a manual or mechanical precount. High volume electronic reprographic machines may be more sensitive to undetected multifed documents than are their light lens equivalent machines, because the electronic reprographic document handler only circulates the document set once, regardless of the number of prints desired. If a multifeed occurs, all prints will be defective Thus, job yield is strongly affected by undetected multifeeds.

The instant disclosure calls for a vacuum actuated multifeed sensor in a wait station region of a reprographic machine. The key idea is that after feeding the documents out of the input tray and prior to scanning by a raster input scanner, the documents would be tested to insure that only one sheet had been feed. As illustrated in the figure, the proposed detection method calls for applying a vacuum to opposite sides of the stationary sheets to be tested by way of a solenoid controlled clamp 12, or nip, and then opening clamp 12 and observing the change in pressure in a common vacuum supply line 14. More specifically, each of the opposing faces of clamp 12 would be annular in shape where the inner circular region thereof would be attached to a vacuum source. This would allow for a vacuum or "suction" to be applied to each side of the clamped document or sheets through the opposing faces of the clamp. As clamp 12 opens, a single sheet 16 will only be able to cover one of the two vacuum ports, 18 or 20. This will cause the pressure in vacuum line 14 to rise...