Browse Prior Art Database

DICOROTRON IMPROVEMENTS

IP.com Disclosure Number: IPCOM000024203D
Original Publication Date: 1979-Dec-31
Included in the Prior Art Database: 2004-Apr-02
Document File: 2 page(s) / 75K

Publishing Venue

Xerox Disclosure Journal

Abstract

Dicorotron devices have been used to perform negative charging functions in an electrophotographic environment. A corona wire is coated with a dielectric material and excited by an AC voltage capacitively coupled to the air across the dielectric sheath. A net DC currefit to the surface to be charged is obtained by applying a DC bias to the surrounding conducting carona shield.

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XEROX DISCLOSURE JOURNAL

DICOROTRON IMPROVEMENTS
Proposed R. W. Gundlach Classification

U.S. c1. 355/3 CL Int. C1. G03g 15/00

5.

Dicorotron devices have been used to perform negative charging functions in an electrophotographic environment. A corona wire is coated with a dielectric material and excited by an AC voltage capacitively coupled to the air across the dielectric sheath. A net DC currefit to the surface to be charged is obtained by applying a DC bias to the surrounding conducting carona shield.

The purpose of the dielectric covering is to provide protection of the wire from corrosive attack by ozone and other products of corona ionization and to provide lower sensitivity to the toner dust that inevitably collects on the wire. The only insulating coating found to date capable of withstanding the corrosive attack of the corona products is glass. Glass is so brittle, however, in a thin coating on a flexible wire that it requires a means of firm support to keep it from cracking in shipment and in use. Any support, however, changes the fields around the coronode. Insulating supports collect charge and quickly negates the DC fields applied by conducting electrodes. A workable solution to this problem is shown in the figure. A corona wire 3 coated with a dielectric layer 4 is held against a movable conducting electrode 5. Movement can be periodic or continuous at a very low rate. A photoconductor 6 is the surface to be charged. An AC voltage is applied to wire...