Browse Prior Art Database

SELF ADJUSTING CORONA DEVICE

IP.com Disclosure Number: IPCOM000022827D
Original Publication Date: 1976-Feb-29
Included in the Prior Art Database: 2004-Mar-26
Document File: 2 page(s) / 219K

Publishing Venue

Xerox Disclosure Journal

Abstract

An electrostatic charging apparatus is shown above in which charging current reaching an imaging surface from a corona discharge device is automatically regulated. The corona device comprises a wire electrode 55 partially surrounded by a grounded metal shield 56. The wire 55 is energized by an a.c. corona generating source 62 which in turn is biased to a d.c. potential provided by a source 63. An imaging surface 58 in the form of a drum comprising a photoconductive surface carried by a con- ductive substrate is rotated adjacent the corona charging device 40,

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SELF ADJUSTING CORONA DEVICE

F. W. Hudson

XEROX DISCLOSURE JOURNAL

Proposed Classification

U.S. Cl. 250/326

mt. Cl, HOlt 19/04

An electrostatic charging apparatus is shown above in which
charging current reaching an imaging surface from a corona
discharge device is automatically regulated. The corona device
comprises a wire electrode 55 partially surrounded by a grounded
metal shield 56. The wire 55 is energized by an a.c. corona
generating source 62 which in turn is biased to a d.c. potential
provided by a source 63. An imaging surface 58 in the form of
a drum comprising a photoconductive surface carried by a con-
ductive substrate is rotated adjacent the corona charging
device 40,

Charging current delivered by the corona device 40 to the
imaging surface is monitored by a sensing means comprising a
resistor R and a capacitor 73 located intermediate the con-
ductive substrate and ground. The voltage across the sensing
means is coupled to one input of a comparator 70, the other
input of the comparator being coupled to a reference potential
on line 72, Deviations of the charging current from the pre-
selected reference result in the variation of the d.c. bias

63 applied to the a.c. energizing source. Thus, a constant
current arrangement is provided.

Volume 1 Number 2 February 1976 67

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68 XEROX DISCLOSURE JOURNAL

Volume 1 Number 2 February 1976

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