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CORONA CHARGING DEVICE

IP.com Disclosure Number: IPCOM000025053D
Original Publication Date: 1983-Jun-30
Included in the Prior Art Database: 2004-Apr-04
Document File: 4 page(s) / 187K

Publishing Venue

Xerox Disclosure Journal

Abstract

This disclosure relates to a self-biasing corona discharge device, for example, a dicorotron, which is suitable for use in conditioning the residual toner on a charge retentive surface, such as a photoreceptor, to thereby facilitate subsequent toner removal therefrom. The foregoing device is utilized in conjunction with a self-biasing detack corona device suitable for use in reducing electrostatic attraction between the copy substrate and the photoreceptor. The self-biasing arrangement used for conditioning the residual toner enables sufficient shield current to be generated to effect the preclean (i.e., residual toner conditioning prior to cleaning) function. The biasing arrangement used in the corona device for conditioning the residual toner is also utilized in connection with the charge and transfer coronode devices thereby permitting all of the corona devices to be powered by a single secondary winding of the power source at reduced power.

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Page 1 of 4

KEROX DISCLOSURE JOURNAL

CORONA CHARGING DEVICE Proposed Vittal U. Shenoy Classification

U.S. Cl. 355/3CH Int. Cl. G03g 15/00

86

Volume 8 Number 3 May/June 1983 23 I

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Page 2 of 4

CORONA CHARGING DEVICE (Cont'd)

*P UA

FIG. 3

RS MEGOHMS

0 I 2 3 4 5 6 7 8 9 10

RS (MEGOHMS)

 XEROX DISCLOSURE JOURNAL Volume 8 Number 3 May/June 1983

0' I I 6

FIG. 2

232

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

Page 3 of 4

CORONA CHARGING DEVICE (Cont'd)

This disclosure relates to a self-biasing corona discharge device, for example, a dicorotron, which is suitable for use in conditioning the residual toner on a charge retentive surface, such as a photoreceptor, to thereby facilitate subsequent toner removal therefrom. The foregoing device is utilized in conjunction with a self- biasing detack corona device suitable for use in reducing electrostatic attraction between the copy substrate and the photoreceptor. The self-biasing arrangement used for conditioning the residual toner enables sufficient shield current to be generated to effect the preclean (i.e., residual toner conditioning prior to cleaning) function. The biasing arrangement used in the corona device for conditioning the residual toner is also utilized in connection with the charge and transfer coronode devices thereby permitting all of the corona devices to be powered by a single secondary winding of the power source at reduced power.

The dicorotron structures (Figure 1) are the same for all of the corona devices but the voltages and biases and methods of applying them are different. In the case of the detack corona device 51, an AC voltage is applied to the dicorotron electrode with the shield connected to ground through an impedance such as a resistor 76. With such an arrangement, when the photoconductive surface with the sheet 40 adhered thereto through electrostatic bonds resulting from the transfer operation, moves through the detack station, the charges contained on the backside of the sheet 40 establish a relatively large electrostatic field between the shield and the copy sheet. This field causes current to flow between the dicorotron electrode and the backside of the copy sheet and between the dicorotron electrode and the shield. Thus, a current flows through the resistor 76 which develops a voltage across it which is the desired shield bias voltage.

Thus, the negatively charged paper passing under the detack dicorotron acts as a current source which due to the relatively large charge on the paper is able to supply between 30 to 40 microamps of DC current which by the proper selection of the value of the resistor 76 supplies the required detack current. Attempts at using the type of biasing used for the detack corotron for the preclean function did not furnish enough current to perform the preclean function. This is because the charge level on the photoreceptor when it passes under the preclean dicorotron is inadequat...