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GRID STRUCTURES FOR DOCUMENT/PAPER SENSOR

IP.com Disclosure Number: IPCOM000025658D
Original Publication Date: 1987-Feb-28
Included in the Prior Art Database: 2004-Apr-04
Document File: 4 page(s) / 175K

Publishing Venue

Xerox Disclosure Journal

Abstract

It is advantageous to know aspects of documents to be copied such as size, and position, principally skew, with respect to an imaging area. One sensor for obtaining this information is a conducting brush in contact with a conducting grid. The passage of paper through the sensor breaks contact between part of the brush and grid and thereby provides information about width, length, and skew of the document from an assessment of those grid lines not electrically in contact with the brush. This infomation is used to reposition the document, to select the proper size copy paper, and to discharge areas of the photoreceptor not required in copying.

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Page 1 of 4

XEROX DISCLOSURE JOURNAL

GRID STRUCTURES FOR DOCUMENT/ PAPER SENSOR U.S. c1.355/3 Joseph J. Wysocki
Richard A. Hudson

Proposed Classification

Int. C1. G03g 15/00

FIG. I

CONVENTIONAL BRUSH
MOUNT1 NG

Volume 12 Number 1 January/February 1987

INVERTED BRUSH
MOUNTING

21

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

Page 2 of 4

GRID STRUCTURES FOR DOCUMENTI PAPER SENSOR (Cont'd)

It is advantageous to know aspects of documents to be copied such as size, and position, principally skew, with respect to an imaging area. One sensor for obtaining this information is a conducting brush in contact with a conducting grid. The passage of paper through the sensor breaks contact between part of the brush and grid and thereby provides information about width, length, and skew of the document from an assessment of those grid lines not electrically in contact with the brush. This infomation is used to reposition the document, to select the proper size copy paper, and to discharge areas of the photoreceptor not required in copying.

There are several problems with such a sensor which limit its life, increase its cost, and cause it to require frequent service. The first problt n is that of wear of grid material caused by the abrasive passage of paper. A second is the coating of the grid by paper debris which will result in erratic contact and misleading document infomation. A third is the charging of insulating portions of the grid assembly not subsequently discharged by the conducting brush; such charging will result in charged paper, paper distortion, and jams.

Wear of grid material caused by the abrasive action of paper is prevented by fabricating the grid below the surface of the substrate which the paper contacts but is still accessible by the brush; i.e., in rectangular notches in the substrate. Although wear can be prevented as well by the addition of risers which elevate the paper above the grid, a preferred way is to etch the insulating substrate, whether plastic, or glass, to provide a notched pattern into which the grid is deposited. Figure 1 illustrates the different structures of the grid 10 on the substrate 12, the use of risers 14, and the grid beneath the surface 13 of the substrate 12 by the distance "d". The use of these schemes will prevent the paper 16 from abrading the grid 10, but they may aggravate the second problem; namely, the accumulation of paper debris. This problem is eliminated by operating the brushlgrid assembly 18 in an unconventional, inverted sense; namely, the grid on top of the brush rather than the brush on top of the grid. In this manner, aper debris will fall through the brush to a

the conventional brush mounting 18 and the inverted brush mounting 20. The final problem of static generation both in the insulated portions of the grid 10 and in the paper 16 is removed by using a resistive substrate 12 rather than an insulator. The substrate area not accessed by the brush 22 certainly need not be perfectly i...