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US3729649A - Corona charging apparatus - Google Patents

Corona charging apparatus Download PDF

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Publication number
US3729649A
US3729649A US00256665A US3729649DA US3729649A US 3729649 A US3729649 A US 3729649A US 00256665 A US00256665 A US 00256665A US 3729649D A US3729649D A US 3729649DA US 3729649 A US3729649 A US 3729649A
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US
United States
Prior art keywords
free end
corona
wire
dielectric
dielectric surface
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Expired - Lifetime
Application number
US00256665A
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English (en)
Inventor
P Chappelle
M Mosehauer
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
Eastman Kodak Co
Original Assignee
Eastman Kodak Co
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Filing date
Publication date
Application filed by Eastman Kodak Co filed Critical Eastman Kodak Co
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Publication of US3729649A publication Critical patent/US3729649A/en
Anticipated expiration legal-status Critical
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    • G—PHYSICS
    • G03—PHOTOGRAPHY; CINEMATOGRAPHY; ANALOGOUS TECHNIQUES USING WAVES OTHER THAN OPTICAL WAVES; ELECTROGRAPHY; HOLOGRAPHY
    • G03G—ELECTROGRAPHY; ELECTROPHOTOGRAPHY; MAGNETOGRAPHY
    • G03G15/00—Apparatus for electrographic processes using a charge pattern
    • G03G15/02—Apparatus for electrographic processes using a charge pattern for laying down a uniform charge, e.g. for sensitising; Corona discharge devices
    • G03G15/0291—Apparatus for electrographic processes using a charge pattern for laying down a uniform charge, e.g. for sensitising; Corona discharge devices corona discharge devices, e.g. wires, pointed electrodes, means for cleaning the corona discharge device

Definitions

  • ABSTRACT Corona charging apparatus for uniformly charging the surface of a dielectric layer supported on a grounded conductive backing.
  • Such apparatus comprises a flexi- Roche ter, N Y, ble corona discharge wire which is perpendicularly arranged, in a cantilever fashion, relative to the central portion of the surface being charged, the free end por- [22] Filed: May 25, 1972 PP NOJ 256,665 tion of such wire extending toward such surface.
  • corona-control electrode posi- 52 US. Cl. ............317/4, 317/262 A, 250/495 oc timed between the free end of the Corona discharge 5 Int Cl 03 15 2 o 19/O4 wire and the dielectric surface, serves to control the 58 Field of Search............................317/4, 262 A; level and uniformity of Charge received y the dielec- 250/49 5 GC 49 5 ZC, 49 5 TC tric surface.
  • references Cited When connected to an appropriate voltage source, the free end of the corona discharge wire [56] References Cited becomes charge-emitting and, due to the field established between it and the combination of the UNITED STATES PATENTS control electrode and the conducting backing of the dielectric layer, oscillates 317/262 A in a random manner, thereby uniformly charging the dielectric surface to a level proportional to the electrical bias of the control 17/4 electrode.
  • This invention relates to electrographic recording, and particularly to methods and apparatus for uniformly charging a dielectric surface, such as the sur- I face of a photoconductive layer.
  • Copy-making via the electrophotographic process commonly includes the steps of uniformly electrostatically charging the photoconductive surface of an electrophotographic recording element while the element is maintainedin darkness, and imagewise exposing such surface to activating radiation, thereby selectively dissipating the uniform charge to form an electrostatic image or charge pattern corresponding to the indicia on the document being copied. This electrostatic image is then rendered visible by the selective deposition of toner particles thereon.
  • uniform charging of'the recording'element is usually accomplished through the use of one or more corona discharge wires. These wires are connected to a source of high voltage and are-arranged in spaced relationship with .the photoconductive surface, extending horizontally across the entire width of the recording element.
  • a novel corona charging apparatus comprising a flexible conductive wire or strand which is per,- pendicularly supported relative to a dielectric surface which is to be charged.
  • the wire is mounted in a cantilever fashion i.e., one end is fixed and the other is free to move) with the free end thereof arranged closer to the dielectric surface than the fixed end.
  • An electrically biased corona-control grid positioned between the free end of the wire and the dielectric surface, serves to control the level and uniformity of charge received by the dielectric surface. Whenhigh voltage is applied to the wire, the free end thereof oscillates randomly, con- I tinuously spraying ions or corona charge toward the dielectric surface.
  • a conductive ring arranged along the periphery of the surface being charged is used in lieu of the aforementioned corona-control grid to regulate the level and uniformity of charging.
  • FIG. 1 is a schematic side elevation of a preferred embodiment of the corona charging apparatus of the invention, illustrating in phantom lines the movement of the vorona discharge wire upon being energized by a source of high voltage;
  • FIGS. 2 and 3 are perspective views of the corona charging apparatus of the invention, illustrating two different forms of the corona-control electrode.
  • a dielectric layer 6 having ground ed conductive backing 7 and a surface S which is to receive a uniform charge is shown positioned beneath the vorona charging apparatus of the invention.
  • Such apparatus comprises a flexible wire 10 (e.g., a stainless steel wire having a diameter of 1.5 mil) which is perpendicularly suspended above surface S.
  • Wire 10 ismounted in a cantilever fashion, one end 11 being rigidly coupled to a dielectric support 12 and the other end 13 being free to move in any direction without constraint, except that inherentin the rigidity of the wire.
  • the upper end 11 of wire 10 is operatively connected to a high voltage source 15, such as a ten kilovolt source, through a switch 16.
  • the length of wire 10 is directly proportional to the surface area being charged.
  • Electrode 17 Positioned between the free end 13 of wire 10 and surface S is a corona-control electrode 17 which, as shown in FIG. 2, preferably comprises an electrically conductive grid 18 having approximately ten grid wires per inch in each direction. Electrode 17 is either electrically biased by an external source (not shown) to the desired charge potential level of surface S or, as shown, connected to ground through a zener diode 20 having a breakdown voltage approximately equal to such charge potential level. Electrode 17 serves 0 control the level and uniformity of charge received by surface S.
  • wire 10 When no voltage is applied to wire 10, it assumes the rest position indicated in the solid lines of FIGS. 1 and 2. However, upon closing switch 16, thereby connecting wire to high voltage source 15, wire 10 begins to oscillate or whip about in a random manner, rapidly flexing about support 12 into various positions such as those indicated in phantom lines in FIGS. 1 and 2. During such random oscillation, a corona discharge 25 takes place between the free end 13 of wire 10 and the corona control grid 18, and, due to the electric field between wire 10 and the combination of grid 18 and backing 7, ions are attracted toward and deposited on dielectric surface S. When the surface of layer 6 is charged to the breakdown voltage of diode 20, no additional charging occurs. The polarity of the deposited charge is determined by the polarity of voltage source 15 and, of course, the orientation of diode 20.
  • corona control electrode 16 is shown to comprise an electrically conductive closed loop 30 which is arranged along the periphery of the dielectric surface area being charged and slightly spaced therefrom.
  • loop 30 is electrically biased to the level of desired surface charge potential, either by an external voltage source or by connecting loop 30 to ground through zener diode 20 as shown.
  • loop serves to regulate the uniformity of charge and the charging level.
  • EXAMPLE 1 A Va inch stainless steel wire mesh or grid was arranged s inch above a photoconductive layer which was to receive a uniform charge.
  • the grid was connected to ground through six 100 volt zener diodes connected in series. The area being charged was approximately one square inch.
  • Vertically suspended above the grid was a 1.5 mil stainless steel wire, approximately 1.5 inch in length.
  • One end of the wire was rigidly connected to a plastic mount, and the other end extended toward the grid and was free to move in any direction. The spacing between the free end of the wire and grid was approximately inch.
  • a 10 kilovolt DC negative potential was applied to the wire for two seconds. During this period the free end thereof oscillated randomly, spraying a corona discharge toward the photoconductive surface. Due to the zener diodes, the grid quickly charged to a voltage of 600 volts. After disconnecting the voltage source, the charge on all portions ofthe photoconductive surface was determined to be Within 5 percent of-600 volts.
  • EXAMPLE 2 The same experiment as that described in Example I was repeated except that the wire grid was replaced with a copper wire loop which was arranged about the periphery of the area being charged, spaced from such surface a distance of approximately /a inch. The diameter of the wire loop was 0.073 inch. The wire loop was connected to ground via six 100 volt zener diodes connected in series. After applying the 10 kilovolt source to the corona discharge wire for approximately two seconds, all areas of the photoconductor surface within the wire loop were found to be charged to within 5 percent of 600 volts. I
  • Corona charging apparatus for substatially uniformly charging a dielectric surface to a predefined charge level; said apparatus comprising a. a flexible wire, perpendicularly arranged relative to said surface and mounted in a cantilever fashion such that the free end thereof extends toward and is spaced from said surface;
  • c. means for attracting said ions toward said dielectric surface.
  • said attracting means comprises means for preventing the charging of said surface beyond said predefined charge level.
  • said attracting means comprises a conductive electrode positioned in a plane between said free end of said wire and said dielectric surface.
  • said electrode comprises a conductive band which at least partially surrounds said dielectric surface.
  • Corona charging apparatus for substantiall uniformly charging a dielectric surface to a predefined charge level, said apparatus comprising:
  • a flexible wire perpendicularly arranged relative to said surface and mounted in a cantilever fashion such that the free end thereof extends toward and is spaced from said surface;
  • a corona-control electrode positioned between the free end of said wire and said surface
  • d. means for electrically biasing said electrode at a level proportional to said predefined charge level, thereby limiting the maximum charge on said surface to said predefined charge level.
  • corona-control electrode comprises a conductive grid.
  • corona-control electrode comprises an endless .loop of conductive material.

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  • Physics & Mathematics (AREA)
  • Engineering & Computer Science (AREA)
  • Plasma & Fusion (AREA)
  • General Physics & Mathematics (AREA)
  • Electrostatic Charge, Transfer And Separation In Electrography (AREA)
US00256665A 1972-05-25 1972-05-25 Corona charging apparatus Expired - Lifetime US3729649A (en)

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
US25666572A 1972-05-25 1972-05-25

Publications (1)

Publication Number Publication Date
US3729649A true US3729649A (en) 1973-04-24

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ID=22973104

Family Applications (1)

Application Number Title Priority Date Filing Date
US00256665A Expired - Lifetime US3729649A (en) 1972-05-25 1972-05-25 Corona charging apparatus

Country Status (6)

Country Link
US (1) US3729649A (ja)
JP (1) JPS4951952A (ja)
BE (1) BE800084A (ja)
CA (1) CA982211A (ja)
DE (1) DE2326547C3 (ja)
GB (1) GB1374557A (ja)

Cited By (10)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3967119A (en) * 1970-12-30 1976-06-29 Rank Xerox Ltd. Corona charging device
US4012666A (en) * 1972-07-22 1977-03-15 U.S. Philips Corporation Method of and device for the removal of electrostatic charges
US4041312A (en) * 1975-04-23 1977-08-09 A. B. Dick/Scott Apparatus for electrostatically charging an electrophotographic film
US4363072A (en) * 1980-07-22 1982-12-07 Zeco, Incorporated Ion emitter-indicator
US4507373A (en) * 1983-10-03 1985-03-26 Eastman Kodak Company Method and apparatus for uniformly charging a surface
US4638397A (en) * 1984-12-21 1987-01-20 Xerox Corporation Self-biased scorotron and control therefor
WO1992011673A1 (fr) * 1990-12-25 1992-07-09 Lev Alexandrovich Pokhmelnykh Dispositif de production de charge d'espace dans l'atmosphere
US5245502A (en) * 1990-11-23 1993-09-14 Xerox Corporation Semi-conductor corona generator for production of ions to charge a substrate
CN103190203A (zh) * 2010-12-28 2013-07-03 株式会社小金井 离子发生装置
US20150123008A1 (en) * 2012-03-08 2015-05-07 Koganei Corporation Ion generator

Families Citing this family (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPS58135752U (ja) * 1982-03-05 1983-09-12 ティーディーケイ株式会社 静電式複写機用帯電装置

Citations (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3303401A (en) * 1962-07-20 1967-02-07 Azoplate Corp Method and apparatus for imparting an electrostatic charge to a layer of insulating material
US3476935A (en) * 1965-08-30 1969-11-04 Commw Of Australia Control of xerographic images by charging the photoconductor with only an outer band of a corona discharge
US3555378A (en) * 1967-05-15 1971-01-12 Commw Of Australia Charging xerographic images
US3656021A (en) * 1970-01-29 1972-04-11 Katsuragawa Denki Kk Corona discharge device

Patent Citations (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3303401A (en) * 1962-07-20 1967-02-07 Azoplate Corp Method and apparatus for imparting an electrostatic charge to a layer of insulating material
US3476935A (en) * 1965-08-30 1969-11-04 Commw Of Australia Control of xerographic images by charging the photoconductor with only an outer band of a corona discharge
US3555378A (en) * 1967-05-15 1971-01-12 Commw Of Australia Charging xerographic images
US3656021A (en) * 1970-01-29 1972-04-11 Katsuragawa Denki Kk Corona discharge device

Cited By (12)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3967119A (en) * 1970-12-30 1976-06-29 Rank Xerox Ltd. Corona charging device
US4012666A (en) * 1972-07-22 1977-03-15 U.S. Philips Corporation Method of and device for the removal of electrostatic charges
US4041312A (en) * 1975-04-23 1977-08-09 A. B. Dick/Scott Apparatus for electrostatically charging an electrophotographic film
US4363072A (en) * 1980-07-22 1982-12-07 Zeco, Incorporated Ion emitter-indicator
US4507373A (en) * 1983-10-03 1985-03-26 Eastman Kodak Company Method and apparatus for uniformly charging a surface
US4638397A (en) * 1984-12-21 1987-01-20 Xerox Corporation Self-biased scorotron and control therefor
US5245502A (en) * 1990-11-23 1993-09-14 Xerox Corporation Semi-conductor corona generator for production of ions to charge a substrate
WO1992011673A1 (fr) * 1990-12-25 1992-07-09 Lev Alexandrovich Pokhmelnykh Dispositif de production de charge d'espace dans l'atmosphere
CN103190203A (zh) * 2010-12-28 2013-07-03 株式会社小金井 离子发生装置
US20130299717A1 (en) * 2010-12-28 2013-11-14 Koganei Corporation Ion generator
US8890070B2 (en) * 2010-12-28 2014-11-18 Koganei Corporation Object neutralization with flexible discharge electrode
US20150123008A1 (en) * 2012-03-08 2015-05-07 Koganei Corporation Ion generator

Also Published As

Publication number Publication date
CA982211A (en) 1976-01-20
BE800084A (fr) 1973-11-26
JPS4951952A (ja) 1974-05-20
GB1374557A (en) 1974-11-20
DE2326547C3 (de) 1975-07-31
DE2326547A1 (de) 1973-11-29
DE2326547B2 (de) 1974-12-05

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