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AINTAINING PHOTORECEPTOR CHARGE POTENTIAL CONSTANT

IP.com Disclosure Number: IPCOM000024122D
Original Publication Date: 1979-Oct-31
Included in the Prior Art Database: 2004-Apr-02
Document File: 2 page(s) / 299K

Publishing Venue

Xerox Disclosure Journal

Abstract

When a corotron used to charge the photoreceptor is operated in either the constant voltage or constant current mode, variations in the incoming photo-receptor potential cause corresponding variation in the outgoing potential. To exemplify this, consider a-charge corotron whose bare plate characteristic curve is given by:

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XEROX DISCLOSURE JOURNAL

AINTAINING PHOTORECEPTOR Proposed Classification

CHARGE POTENTIAL CONSTANT U.S. CL 250/324 Srian E. Springett mt. Cl, H01t 19/04

\Vhen a corotron used to charge the photoreceptor is operated in either the

constant voltage or constant current mode, variations in the incoming photo~ receptor potential cause corresponding variation in the outgoing potential. To exemplify this, consider a~charge corotron whose bare plate characteristic curve is given by:

= S ~i/S) v~] Equation (1)

where is the current to the bare plate at a plate bias VP, I is the plate current at zero plate bias and S is the slope of the corotron~sbare plate characteristic curve, assumed linear for present purposes.

If ~PR is the outgoing photoreceptor potential, then under conditions of constant bias, i.e., I and S are constant,

VPR = (i/S) (1 ecv) + V

1

this variation can be minimized but not eliminäted~

A charging process that uses two corotrons eliminates variations in VPR due to variations in V.. The subscript 1 stands for the first corotron which is operated in a constant vo1ta~e mode. The photoreceptor potential after exposure to the first

corotron is Vf where

Vf = (1 el~) + Ve~Sl/cv Equation (4)

and

e cv Equation (2)

where c is the capacitance per unit area of the photoreceptor and v is its velocity, V

1 is the incoming potential. Under conditions of constant, dynamic current, J~,

VPR = (3d/c\/) + V~. Equation (3)

Therefore, from either equation (2) or (3), VPR varies as V

1 varies. If S/cv is large,

= cv(Vf V). Equation (5)

1

Volume 4 Number 5 September/October 1979 607...