Browse Prior Art Database

ERASE PATCH VALVE

IP.com Disclosure Number: IPCOM000024267D
Original Publication Date: 1980-Feb-29
Included in the Prior Art Database: 2004-Apr-02
Document File: 2 page(s) / 74K

Publishing Venue

Xerox Disclosure Journal

Abstract

In an electrophotographic printing machine, it is frequently desirable to form a sample voltage patch in the inter-image zone. A volt meter measures the potential of the sample patch and controls the charge of a corona generating device. In operation, it is desirable to erase this patch so as to preclude development thereof. In this way, extraneous development is prevented so as to minimize waste of toner material.

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XEROX DISCLOSURE JOURNAL

ERASE PATCH VALVE
Proposed J. H. Dearlove Classification

U.S. c1. 355/3

Int. Cl. G03g 15/00

FIG. 2

Volume 5 Number 1 January/February 1980 77

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ERASE PATCH VALVE (Cont'd)

In an electrophotographic printing machine, it is frequently desirable to form a sample voltage patch in the inter-image zone. A volt meter measures the potential of the sample patch and controls the charge of a corona generating device. In operation, it is desirable to erase this patch so as to preclude development thereof. In this way, extraneous development is prevented so as to minimize waste of toner material.

In order to discharge the sample patch, it must be illuminated. Hence, the sample patch must be illuminated when it is desirable to place the machine in the run mode rather than in the calibration mode. To this end, a valve (indicated generally by the reference numeral 10) comprises a light source 12 which illuminates light bar
14. Light bar 14 focuses the light rays on the photoreceptor in the region of the sample patch. In order to inhibit illumination of the sample patch, shutter 16 is closed. Shutter 16 is interposed between light source 12 and light bar 14. Actuation of electromagnet 18 closes shutter 16. Alternatively, de-energization of electromagnet 18 opens shutter 16. During testing of the sample patch potential, electromagnet 18 is actuated closing shutter 16 blocking light rays from...