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ENHANCED ELECTROSTATIC VOLTMETER MEASUREMENTS

IP.com Disclosure Number: IPCOM000027271D
Original Publication Date: 1996-Feb-29
Included in the Prior Art Database: 2004-Apr-07
Document File: 2 page(s) / 116K

Publishing Venue

Xerox Disclosure Journal

Abstract

Proposed is an enhancement to a built-in Electrostatic Voltmeter (ESV) used to measure photoreceptor surface voltages in a xerographic printing machine. The enhancement provides additional capability to the ESV for measuring other critical voltages. Consequently, all of the critical xerographic voltages are placed on a common measurement basis to substantially reduce total system variability. This is especially important in high quality color printing where relative voltage accuracies of 5 to 10 volts are required.

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XEROX DISCLOSURE JOURNAL

ENHANCED ELECTROSTATIC Proposed Classification VOLTMETER MEASUREMENTS U.S. C1.324/458 Douglas A. Kreckel Int. C1. GOlr 28/12

Proposed is an enhancement to a built-in Electrostatic Voltmeter (ESV) used to measure photoreceptor surface voltages in a xerographic printing machine. The enhancement provides additional capability to the ESV for measuring other critical voltages. Consequently, all of the critical xerographic voltages are placed on a common measurement basis to substantially reduce total system variability. This is especially important in high quality color printing where relative voltage accuracies of 5 to 10 volts are required.

A fundamental difficulty exists in achieving precise control over a critical xerographic parameter comprised of two voltages when only one voltage is measured. Two such parameters are development potential (Vdev) and cleaning potential (Vclean) where:

Vdev = Vddp -Vbias Vclean = Vbias -Vbkgd

and

Vddp is the undischarged photoreceptor voltage;

Vbkgd is the discharged photoreceptor voltage; and

Vbias is the voltage supplied to the developer housing.

Voltage control on the photoreceptor is maintained by a control loop having an ESV to measure Vddp and Vbias thereon. These voltages change simultaneously and are increased or decreased by adjusting the output of a corona charging device. Vbias is independently maintained by selecting a set point and using it as a control voltage on a power supply. If the bias control voltage is in error by a value of +Ebias with regard to Vddp and Vbkgd then, Vdev is reduced and Vclean is increased in accordance with:

Vdev = Vddp - Vbias - Ebias

and

Vclean = Vbias + Ebias -Vbkgd

XEROX DISCLOSURE JOURNAL - Vol. 21, No. 1 January/February 1996 11

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ENHANCED ELECTROSTATIC VOLTMETER MEASUREMENTS (Cont'd)

These errors add a significant contributio...