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CIRCUIT FOR OBTAINING A STEEP CHARACTERISTIC SLOPE FOR A FLAT INTEGRATED COROTRON

IP.com Disclosure Number: IPCOM000024072D
Original Publication Date: 1979-Aug-31
Included in the Prior Art Database: 2004-Apr-02
Document File: 2 page(s) / 239K

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 current to the surface to be charged is obtained by applying a DC bias to the surrounding corona shield.

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XEROX DISCLOSURE JOURNAL

CIRCUIT FOR OBTAINING A STEEP CHARACTERISTIC SLOPE FOR A FLAT INTEGRATED COROTRON

Dror Sand

Proposed Classification
U.S. CL 355/3 CH

mt. CL G03g 15/00

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 current to the surface to be charged is obtained by applying a DC bias to the surrounding corona shield.

To eliminate wire vibration problems, it is known to mount the wire directly on the shield, an arrangement known as a flat integrated corotron, The DC current, ip, delivered to the surface follows closely the following expression:

ip = A 1) e~~"

where Vw is the wire AC excitation, YB the threshold voltage for corona, A and B are determined by the geometry of the device and properties of the charge carriers, d is the plate to shield spacing, and Vsp is the potential difference between the two.

The slope (~~)Vsp = 0 is rather shallow, but by employing the circuit as shown in the figure, the slope can be increased by an appreciable amount.

In the figure, AC supply 2 applies voltage Vw to dicorotron wire 3. The DC bias on shield 4 is modulated by a potential Vs applied from DC supply 5. Vp is the voltage measured at xerographic plate 6, the surface to be charged.

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Volume 4 Number 4 3uly/August 1979 499

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