Browse Prior Art Database

SHEET SIZE SENSOR

IP.com Disclosure Number: IPCOM000025367D
Original Publication Date: 1984-Dec-31
Included in the Prior Art Database: 2004-Apr-04
Document File: 2 page(s) / 111K

Publishing Venue

Xerox Disclosure Journal

Abstract

A system of measuring the dimension of an original document or copy belt moving into or through a copier document feeder or paper path, specifically the dimension of the sheet transverse the direction of sheet movement. An elongate multiple (e.g. 5000) fiber brush is mounted transversely to and over the sheet path in a common conductive clamp, comparable to static eliminator brush systems as disclosed in U.S. Patents Nos. 4,336,565 or 3,757,164 except that here the brush fibers per se are resistive, e.g. approximately 1 megohm resistance each, and approximately .001 inch diameter each. Also, each brush fiber is positioned to contact and be deflected by passage of a sheet thereunder. When no sheet is present the brush fibers contact an electrically conductive, e.g. metal, and grounded, plate extending under the brush. This plate is mounted on the opposite side of the paper path so that each sheet passes between the brush and the plate, interrupting contact with the plate only with that portion of the brush fibers corresponding to the transverse dimension of the sheet.

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XEROX DISCLOSURE JOURNAL

SHEET SIZE SENSOR Proposed Thomas Acquaviva Classification

U.S. CI. 355/14SH Int. C1. G03g 15/00

A system of measuring the dimension of an original document or copy belt moving into or through a copier document feeder or paper path, specifically the dimension of the sheet transverse the direction of sheet movement. An elongate multiple
(e.g. 5000) fiber brush is mounted transversely to and over the sheet path in a common conductive clamp, comparable to static eliminator brush systems as disclosed in U.S. Patents Nos. 4,336,565 or 3,757,164 except that here the brush fibers per se are resistive, e.g. approximately 1 megohm resistance each, and approximately .001 inch diameter each. Also, each brush fiber is positioned to contact and be deflected by passage of a sheet thereunder. When no sheet is present the brush fibers contact an electrically conductive, e.g. metal, and grounded, plate extending under the brush. This plate is mounted on the opposite side of the paper path so that each sheet passes between the brush and the plate, interrupting contact with the plate only with that portion of the brush fibers corresponding to the transverse dimension of the sheet.

Sensing the total resistance between the (common) brush mounting and the plate gives an electrical resistance measurement proportional to the sheet's transverse dimension, since the total parallel resistance of the brush fibers varies with the number of fibers "connected" to the plate. Thus, a single row of high resistance brush fibers may be used as a width detector for a document and for providing a corresponding control signal, e.g. for controlling a photoreceptor fadeout lamp so as to erase any background imaging around the actual image of a small or reduced image document which is being imaged onto a larger copy sheet or imaged with optical reduction. (See, IBM Technical Disclosure Bulletin, Volume 19, Number 6,
November 1976, pages 1983-1984). This is accomplished merely by such resistance sensing of the total number of fibers separated from normal contact with the common conductor bar during the passage of the paper. That is, the brush may be connected to a single, simple, non-critical, parallel res...