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TRANSFER CHARGE MAINTAINING SYSTEM

IP.com Disclosure Number: IPCOM000023241D
Original Publication Date: 1977-Feb-28
Included in the Prior Art Database: 2004-Mar-29
Document File: 2 page(s) / 270K

Publishing Venue

Xerox Disclosure Journal

Abstract

In an electrostatographic copier 10 in which imaging mater-ial is transferred from an image support surface 12 to an overlying copy sheet 26 in a transfer station 32 by elec-trical transfer charges, the variable leakage conduction of these transfer charges by the copy sheet away from the transfer area to contacting conductive sheet guide members 30, 42, etc., changes the available transfer field strength, thus affecting transfer efficiency and quality. Here the conductive members 30, 42 contacting the copy sheet 26 while it is in the transfer station are electrically con-nected to ground only through a high resistance 33, 35 whereby the transfer leakage currents through the paper provide a compensatory self-biasing floating voltage on the conductive guide surfaces which opposes these leakage currents. This voltage bias self-grounds through the re-sistor paths 33,35 when charged paper is not present. In the arrangement here 100 to 400 megohm resistances can suppress the leakage current, but much of the effect can be achieved by lower resistance values generating bias volt-

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Page 1 of 2

XEROX DISCLOSURE JOURNAL

TRANSFER CHARGE NA.flsTI'AIISFING SYS TEN Stephen Borostyan

Proposed Classification

TJ,S. Cl. 317/262A
mt. Cl. HOig

I0

In an electrostatographic copier 10 in which imaging mater-
ial is transferred from an image support surface 12 to an
overlying copy sheet 26 in a transfer station 32 by elec-
trical transfer charges, the variable leakage conduction of
these transfer charges by the copy sheet away from the
transfer area to contacting conductive sheet guide members
30, 42, etc., changes the available transfer field strength,
thus affecting transfer efficiency and quality. Here the
conductive members 30, 42 contacting the copy sheet 26
while it is in the transfer station are electrically con-
nected to ground only through a high resistance 33, 35
whereby the transfer leakage currents through the paper
provide a compensatory self-biasing floating voltage on the
conductive guide surfaces which opposes these leakage
currents. This voltage bias self-grounds through the re-
sistor paths 33,35 when charged paper is not present. In
the arrangement here 100 to 400 megohm resistances can
suppress the leakage current, but much of the effect can be
achieved by lower resistance values generating bias volt-

Volume 2 Number 1 January/February 1977 43

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Page 2 of 2

TRA1~SFER CH7~RGE MAINTAINING SYSTEM (Cont'd)

ages lower than the transfer voltages, e.g., to megohms producing 450 volts bias, The resistance paths may be...