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Browse Prior Art Database

PROTECTIVE PLATINGS FOR BEKYLLIUM COPPER SCOROTKON SCREENS

IP.com Disclosure Number: IPCOM000025766D
Original Publication Date: 1987-Dec-31
Included in the Prior Art Database: 2004-Apr-04
Document File: 2 page(s) / 185K

Publishing Venue

Xerox Disclosure Journal

Abstract

It has been found that when using corona generating devices that produce a negative corona desirable for use particularly with AMAT-type photoconductive surfaces operating with a negatively charged surface, certain difficulties may be observed. It is believed that various nitrogen oxide species are produced by the corona, and that these nitrogen oxide species are adsorbed by solid surfaces. In particular, it is believed that these oxide species are adsorbed by the conductive shield, the housing and the screen or control grid of the corona generating device. This adsorption occurs despite the fact that, during operation of an electrophotographic machine, the corona generating device may be provided with a directed air flow to remove nitrogen oxide species as well as ozone from the area adjacent the corona generating device. After exposure to the nitrogen oxide species, when the electrophotographic machine is turned off for an extended period, and corona is not produced by the corona generating device, the adsorbed nitrogen oxide species are gradually desorbed, i.e., the adsorption is a physically reversible process. When operation of the machine is resumed, a copy quality defect is observed in the copies produced comprising a line image deletion or lower density image formed across the photoconductive surface at the portion of the surface which was at rest opposite the corona generating device during the period of idleness.

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XEROX DISCLOSURE JOURNAL

Proposed C 1 assi fi ca ti on

It has been found that when using corona generating devices that produce a negative corona desirable for use particularly with AMAT-type photoconductive surfaces operating with a negatively charged surface, certain difficulties may be observed. It is believed that various nitrogen oxide species are produced by the corona, and that these nitrogen oxide species are adsorbed by solid surfaces. In particular, it is believed that these oxide species are adsorbed by the conductive shield, the housing and the screen or control grid of the corona generating device. This adsorption occurs despite the fact that, during operation of an electrophotographic machine, the corona generating device may be provided with a directed air flow to remove nitrogen oxide species as well as ozone from the area adjacent the corona generating device. After exposure to the nitrogen oxide species, when the electrophotographic machine is turned off for an extended period, and corona is not produced by the corona generating device, the adsorbed nitrogen oxide species are gradually desorbed, i.e., the adsorption is a physically reversible process. When operation of the machine is resumed, a copy quality defect is observed in the copies produced comprising a line image deletion or lower density image formed across the photoconductive surface at the portion of the surface which was at rest opposite the corona generating device during the period of idleness.

While the mechanism of the interaction of the desorbed nitrogen oxide species and the photoconductive surface is not fully understood, it is believed that the oxide species in some way interact with the photoconductive surface, increasing lateral conductivity so that the surface cannot retain a charge in image fashion for development with toner. This causes narrow line images to blur or to wash out and remain undeveloped after toner is brought into contact with the surface. This defect, sometimes referred to as "parking deletion", increases in severity with prolonged exposure of the photoconductive surface to the desorbing nitrogen oxide species during extended periods of idleness. It has been observed even after a relatively short period of operation, coupled with an extended period of idleness

Where a scorotron is used for charging a photoconductive surface, it has been found that the material from which the scorotron screen is fabricated has a significant effect on the severity of parking deletions. Heretofore, a stainless steel screen or grid has commonly been used. Other materials have been proposed without success, such as such as Monel, Inconel or other corrosion

Volume 12 Number 6 November/December 1987 273

PROTECTIVE PLATINGS FOR BEKYLLIUM COPPER SCOROTKON U.S. C1.355/3CH SCREENS Int. C1. G03g 15/00 Joseph H. Lang
David J. McEwen

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PROTECTIVE PLATINGS FOR BERYLLIUM COPPER SCOROTRON

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