US3678350A - Electric charging method - Google Patents

Electric charging method Download PDF

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US3678350A
US3678350A US134940A US3678350DA US3678350A US 3678350 A US3678350 A US 3678350A US 134940 A US134940 A US 134940A US 3678350D A US3678350D A US 3678350DA US 3678350 A US3678350 A US 3678350A
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corona discharge
insulating member
discharge electrode
charged
charge
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US134940A
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Seiji Matsumoto
Masamichi Sato
Osamu Fukushima
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Xerox Corp
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Xerox Corp
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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
    • G03G15/0266—Arrangements for controlling the amount of charge

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  • an electrophotographic material comprising a photoconductive insulating layer on an electroconductive base is electrically charged generally by means of corona discharge, the charged material is exposed to light from an image and subsequently electrically charged particles are deposited selectively thereon so as to produce a visible image.
  • the amount of electric charge deposited on the material varies with the conditions associated with the corona discharge, such as relative humidity, contamination of the charging electrode, etc. or with the variation of the distance between the corona discharge electrode and the surface of the electrophotographic material to be electrically charged.
  • variation in the voltage being applied to the corona discharge electrode has its efiect manifested in the variation of relative speed when the electrophotographic material and the corona discharge electrode are in relative motion.
  • the present invention relates to charging apparatus for minimizing the variation in the amount of electric charge deposited on an insulating surface.
  • the surface of the insulating material is charged to a magnitude smaller than the desired amount of charge by a first charging electrode.
  • the amount of electric charge deposited is subsequently detected and a signal corresponding thereto is coupled to a comparison means which generates a signal proportional to the difference between the detected signal and a signal corresponding to the desired amount of charge.
  • the difference signal is coupled to a second charging electrode spaced apart from the first charging electrode which generates an electric charge of a magnitude to bring the total charge applied to the surface of the insulating material substantially equal to the desired amount of charge.
  • FIG. 1 is a block diagram of apparatus for use in a first embodiment of the present invention
  • FIG. 2 is a block diagram of apparatus for use in a second embodiment of the present invention.
  • FIG. 3 is the power source and comparison means for the adjustable corona discharge electrode
  • FIG. 4 is a third embodiment of apparatus utilized in the present invention.
  • a photoconductive insulating layer 1 obtained for example by mixing zinc oxide powder with an insulating resin such as silicone resin, is formed on a conduc tive base member 2, made for example of a paper processed so as to acquire electroconductivity or a resin film having a conductive material vacuum deposited thereon, forming a photoconductive insulating member mounted on support 3.
  • the support 3 is capable of movement in the direction of arrow 4.
  • a plurality of corona discharge electrodes, or wires, 5 are partially enclosed by shield case 6.
  • a high voltage power source 7 from about 3 KV to approximately 10 KV in magnitude is applied to corona wires 5, the photoconductive insulating layer 1 being electrically charged in an amount approximately 50 percent of the desired magnitude of chargefl'A detecting head 8 for detecting the surface potential of the portion of the insulating layer 1 which has been charged by the first corona wires 5 is connected to surface electrometer 9, the output thereof being connected to delay circuit 10.
  • the output of delay circuit 10 is coupled to a second corona discharge electrode, or wire, 12 via a high voltage power source 11. It is preferred to retain the charging efficiency of the second corona discharge electrode 12 less than that of the first corona discharge electrode 5.
  • the surface potential detected by head 8 is transmitted as an electric signal and displayed on the surface electrometer 9.
  • This electric signal is so delayed by delay circuit 10 as to cause the second corona wire 12 to be energized when the portion of the surface of insulating layer 1 at which the corresponding detection was made by the head 8 has advanced and arrived directly below the second corona discharge wire 12.
  • the delayed signal causes the voltage applied to the second corona discharge wire 12 to be changed in proportion to the difference of the detected charge from the desired surface charge.
  • the power source 11 for generating a variable voltage dependent upon the difference in detected charge is described hereinbelow with reference to FIG. 3. If, for example, the potential applied to the second corona wire 12 from the'high voltage power source 1 1 increases with the increasing difference between the amount of electric charge detected-by head 8 and the desired magnitude of electric charge, the corona discharge generated by second corona discharge wire 12 is adjusted to being the amount of electric charge at the detected portion of the photoconductive insulating layer 1 to the desired magnitude of charge. Where the difference is small, the potential to be applied to the second corona wire 12 is lowered proportionally. Thus, possible dispersion in the amount of electric charge deposited on the surface of insulating layer 1 is decreased.
  • FIG. 2 illustrates another embodiment of the present invention. This embodiment is similar to that illustrated in FIG. 1, except the photoconductive insulating material is in the form of a roll of sensitive paper which is driven in the direction of arrow 4 on support 3.
  • a screen grid 13 for controlling the amount of corona discharge by the first corona wires 5 and screen grid 14 for the second corona wire 12 are also illustrated.
  • a power source 15 is used to apply a fixed potential to' the screen grid 13. By disposing screen grid 13 at a fixed potential adjacent corona wires 5, it becomes possible to carry out stable corona discharge and consequent uniform electric charging. Further, screen grid 14 serves to facilitate the control of the corona discharge of the second corona wire 12.
  • FIG. 3 shows an embodiment of an adjustable power source for the second corona discharge electrode 12.
  • a fixed voltage source 17 is coupled to one input of operational amplifier 18, the output thereof being connected to motor 19.
  • a high voltage transformer 20, having primary and secondary coils 21 and 22, respectively, has its primary coil connected to power source 23.
  • the signal from delay circuit is compared with the voltage generated by fixed power source 17, corresponding to the desired amount of charge, in operational amplifier 18.
  • the primary coil 21 of high voltage transformer 20, excited by power source 23, induces a high voltage in secondary coil 22.
  • the position of a tap on the primary coil 21 is controlled by motor 19, and where the measured surface charge or potential, is less than the desired value, the tap is moved in a direction to increase the coil rate (number of coils) in the primary, thereby increasing the voltage at the secondary coil 22.
  • the coil rate may be decreased by moving the position of the tap in the opposite direction thereby decreasing the secondary voltage.
  • the voltage at the secondary side of high voltage transformer is transformed to a direct current by a rectifying circuit comprising diode 24 and capacitor 25, the output of the rectifying circuit being connected to the secondary corona discharge electrode 12.
  • the amount of electric charge deposited on the insulating surface is controlled by regulating the amount of corona discharge.
  • the amount of electric charge can be varied by controlling the distance between the corona discharge electrode and the surface of the insulating member to be charged by lessening this distance for an increased amount of electric charge and increasing the distance for adecreased amount of electric charge.
  • FIG. 4 With the apparatus shown in FIG. 4, the charge generated by the secondary corona discharge electrode 12 is controlled by actuating the electrode either towards or away from the surface of insulating layer 1.
  • the motor 19, shown in FIG. 3, in this embodiment is controlled by operational amplifier 18 and drives an arm 20 in response to the difference in the measured surface potential.
  • the arm 20 is coupled to the shield partially enclosing the electrode 12, the secondary corona discharge electrode 12 being driven up and down as arm 20 rotates about pivot point 27.
  • the rotation of motor 19 can be communicated to the arm 20 by means of a link system and/or wire (not shown).
  • the charge value is increased when the corona discharge electrode approaches the surface of insulating layer 1 and is decreased when the electrode moves away from it.
  • motor 19 actuates arm' 20 to move the secondary corona discharge electrode 12 away from insulating layer 1 when the surface potential measured by detector 8 is too large, and to move electrode 12 towards the surface when too small.
  • the voltage applied to secondary corona discharge electrode 12 may be of a fixed value such as that applied by source 26, and the high voltage transformer circuit shown in FIG. 3 would not be required.
  • the voltage applied to the first and second corona discharge 7 electrodes may be of direct current. Alternatively, direct and alternate currents may be used together.
  • the member to be charged has been generally characterized as an electrophotographic layer overlying a conductor
  • the present invention may be utilized with equal facility with an electrically insulating material formed on a conductive support.
  • a layer of plastic formed on a conductive support may be uniformly and efficiently charged with the apparatus of the present invention.
  • Apparatus for uniformly charging the surface of an insulating member to a predetermined charge magnitude comprising:
  • Apparatus for uniformly charging the surface of an insulating member to a predetermined charge magnitude comprising:

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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)

Abstract

Apparatus for uniformly charging the surface of an insulating member by first charging a portion of the surface to a magnitude smaller than the desired amount of charge by a first charging electrode. The amount of charge thus deposited is subsequently detected and compared with the desired amount of charge to be deposited. As a result of the comparison, a second charging electrode, spaced apart from the first charging electrode, is energized whereby the total charge applied to the portion of the insulating member previously charged is substantially equal to the desired amount of charge.

Description

United States Patent Matsumoto et a1.
[4 1 July 18,1972
[541 ELECTRIC CHARGING METHOD [72] Inventors: Seljl Matsumoto; Mlsamlchl Sato; Osamu Fukushlma, all of Asaki, Japan [73] Assignee: Xerox Corporation, Stamford, Conn.
[22] Filed: April 19, 1971 [211 Appl. No.: 134,940
[52] US. Cl ..317/262 A, 250/49.5 ZC [51] Int. Cl. ..1-l0lt 19/00 [58] Field of Search ..317/262 A; 250/49.5 GC, 49.5 ZC
[ 56] References Cited UNITED STATES PATENTS 3,586,908 6/1971 Vosteen ..317/262 A 3,582,731 6/1971 Scto et a1. ..317/262 A 3,604,925 9/1971 Snelling ..317/262 A 3,013,203 12/1961 Allen et al. ..250/49.5 ZC
Primary Examiner-J. D. Miller Assistant Examiner-Harry E. Moose, Jr.
Attorney-James J. Ralabate, Albert A. Mahassel, John E. Beck and Irving Keschner ABSTRACT Apparatus for uniformly charging the surface of an insulating member by first charging a portion of the surface to a magnitude smaller than the desired amount of charge by a first charging electrode. The amount of charge thus deposited is subsequently detected and compared with the desired amount of charge to be deposited. As a result of the comparison, a second charging electrode, spaced apart from the first charging electrode, is energized whereby the total charge applied to the portion of the insulating member previously charged is substantially equal to the desired amount of charge.
4 Claim, 4 Drawing Figures PATENIED JUL! 8 I972 SHEET 1 BF 2 INVENTORK SEIJI MATSUMOTO MASAMICHI SATO HY OSAMU FUKUSHIMA ORMEY PATENIEU JUL18 I912 SHEET 2 BF 2 I TO CORONA DISCHARGE ELECTRODE l2 BACKGROUND OF THE INVENTION In the art of electrophotography, an electrophotographic material comprising a photoconductive insulating layer on an electroconductive base is electrically charged generally by means of corona discharge, the charged material is exposed to light from an image and subsequently electrically charged particles are deposited selectively thereon so as to produce a visible image. When the electrophotographic material is subjected to electric charging, the amount of electric charge deposited on the material varies with the conditions associated with the corona discharge, such as relative humidity, contamination of the charging electrode, etc. or with the variation of the distance between the corona discharge electrode and the surface of the electrophotographic material to be electrically charged. In particular, where sufficient electric charging is to be accomplished in a short period of time, variation in the voltage being applied to the corona discharge electrode has its efiect manifested in the variation of relative speed when the electrophotographic material and the corona discharge electrode are in relative motion.
SUMMARY OF THE INVENTION The present invention relates to charging apparatus for minimizing the variation in the amount of electric charge deposited on an insulating surface. In particular, the surface of the insulating material is charged to a magnitude smaller than the desired amount of charge by a first charging electrode. The amount of electric charge deposited is subsequently detected and a signal corresponding thereto is coupled to a comparison means which generates a signal proportional to the difference between the detected signal and a signal corresponding to the desired amount of charge. The difference signal is coupled to a second charging electrode spaced apart from the first charging electrode which generates an electric charge of a magnitude to bring the total charge applied to the surface of the insulating material substantially equal to the desired amount of charge.
It is an object of the present invention to provide novel apparatus for uniformly charging the surface of an insulating material. I
It is a further object of the present invention to provide novel method and apparatus for uniformly charging the surface of an electrophotographic material.
It is still a further object of the present invention to uniformly charge the surface of an insulating material by first charging the surface to a magnitude smaller than the desired amount of charge by a first charging electrode. The amount of charge is subsequently detected and compared with the desired amount of charge to be deposited. As a result of the comparison, a second charging electrode, spaced apart from the first charging electrode, is energized whereby the total charge applied to the insulating surface is substantially equal to the desired amount of charge.
DESCRIPTION OF THE DRAWING For a better understanding of the invention as well as other objects and further features thereof, reference is made to the following description which is to be read in conjunction with the accompanying drawings wherein:
FIG. 1 is a block diagram of apparatus for use in a first embodiment of the present invention;
FIG. 2 is a block diagram of apparatus for use in a second embodiment of the present invention;
FIG. 3 is the power source and comparison means for the adjustable corona discharge electrode; and
FIG. 4 is a third embodiment of apparatus utilized in the present invention.
DESCRIPTION OF THE PREFERRED EMBODIMENTS Referring now to FIG. 1, a photoconductive insulating layer 1, obtained for example by mixing zinc oxide powder with an insulating resin such as silicone resin, is formed on a conduc tive base member 2, made for example of a paper processed so as to acquire electroconductivity or a resin film having a conductive material vacuum deposited thereon, forming a photoconductive insulating member mounted on support 3. The support 3 is capable of movement in the direction of arrow 4. A plurality of corona discharge electrodes, or wires, 5 are partially enclosed by shield case 6. A high voltage power source 7 from about 3 KV to approximately 10 KV in magnitude is applied to corona wires 5, the photoconductive insulating layer 1 being electrically charged in an amount approximately 50 percent of the desired magnitude of chargefl'A detecting head 8 for detecting the surface potential of the portion of the insulating layer 1 which has been charged by the first corona wires 5 is connected to surface electrometer 9, the output thereof being connected to delay circuit 10. The output of delay circuit 10 is coupled to a second corona discharge electrode, or wire, 12 via a high voltage power source 11. It is preferred to retain the charging efficiency of the second corona discharge electrode 12 less than that of the first corona discharge electrode 5. It is possible to control charging efficiency by controlling the distance between the corona discharge electrode and the surface of the insulating member, the distance preferably being in the range from about 10 to about 50 mm. The surface potential detected by head 8 is transmitted as an electric signal and displayed on the surface electrometer 9. This electric signal is so delayed by delay circuit 10 as to cause the second corona wire 12 to be energized when the portion of the surface of insulating layer 1 at which the corresponding detection was made by the head 8 has advanced and arrived directly below the second corona discharge wire 12. At the same time the delayed signal causes the voltage applied to the second corona discharge wire 12 to be changed in proportion to the difference of the detected charge from the desired surface charge. The power source 11 for generating a variable voltage dependent upon the difference in detected charge is described hereinbelow with reference to FIG. 3. If, for example, the potential applied to the second corona wire 12 from the'high voltage power source 1 1 increases with the increasing difference between the amount of electric charge detected-by head 8 and the desired magnitude of electric charge, the corona discharge generated by second corona discharge wire 12 is adjusted to being the amount of electric charge at the detected portion of the photoconductive insulating layer 1 to the desired magnitude of charge. Where the difference is small, the potential to be applied to the second corona wire 12 is lowered proportionally. Thus, possible dispersion in the amount of electric charge deposited on the surface of insulating layer 1 is decreased.
FIG. 2 illustrates another embodiment of the present invention. This embodiment is similar to that illustrated in FIG. 1, except the photoconductive insulating material is in the form of a roll of sensitive paper which is driven in the direction of arrow 4 on support 3. A screen grid 13 for controlling the amount of corona discharge by the first corona wires 5 and screen grid 14 for the second corona wire 12 are also illustrated. A power source 15 is used to apply a fixed potential to' the screen grid 13. By disposing screen grid 13 at a fixed potential adjacent corona wires 5, it becomes possible to carry out stable corona discharge and consequent uniform electric charging. Further, screen grid 14 serves to facilitate the control of the corona discharge of the second corona wire 12. When the potential applied to the second corona wire 12 is changed, a heavy change in the amount of corona discharge may result, making it rather difiicult to obtain uniform electric charging. Simple control can be achieved for making the necessary increase of the amount of electric charge by increasing the potential of the power source 11 in accordance with the signals detected by head 8 and, at the same time, lowering the potential of the power source 16 for the screen grid 14. The amount of corona discharge can also be changed by varying the potential applied to screen grid 14 without changing the potential applied to the second corona wire 12. Sensitive paper 1 may be driven continuously or intermittently, whichever is preferred.
FIG. 3 shows an embodiment of an adjustable power source for the second corona discharge electrode 12. A fixed voltage source 17 is coupled to one input of operational amplifier 18, the output thereof being connected to motor 19. A high voltage transformer 20, having primary and secondary coils 21 and 22, respectively, has its primary coil connected to power source 23. The signal from delay circuit is compared with the voltage generated by fixed power source 17, corresponding to the desired amount of charge, in operational amplifier 18. The primary coil 21 of high voltage transformer 20, excited by power source 23, induces a high voltage in secondary coil 22. The position of a tap on the primary coil 21 is controlled by motor 19, and where the measured surface charge or potential, is less than the desired value, the tap is moved in a direction to increase the coil rate (number of coils) in the primary, thereby increasing the voltage at the secondary coil 22. Alternatively, if the measured surface potential is too large, the coil rate may be decreased by moving the position of the tap in the opposite direction thereby decreasing the secondary voltage. The voltage at the secondary side of high voltage transformer is transformed to a direct current by a rectifying circuit comprising diode 24 and capacitor 25, the output of the rectifying circuit being connected to the secondary corona discharge electrode 12.
In the embodiments shown in FIGS. 1 and 2, the amount of electric charge deposited on the insulating surface is controlled by regulating the amount of corona discharge. Altematively, the amount of electric charge can be varied by controlling the distance between the corona discharge electrode and the surface of the insulating member to be charged by lessening this distance for an increased amount of electric charge and increasing the distance for adecreased amount of electric charge. This embodiment is shown in FIG. 4. With the apparatus shown in FIG. 4, the charge generated by the secondary corona discharge electrode 12 is controlled by actuating the electrode either towards or away from the surface of insulating layer 1. The motor 19, shown in FIG. 3, in this embodiment is controlled by operational amplifier 18 and drives an arm 20 in response to the difference in the measured surface potential. The arm 20 is coupled to the shield partially enclosing the electrode 12, the secondary corona discharge electrode 12 being driven up and down as arm 20 rotates about pivot point 27. The rotation of motor 19 can be communicated to the arm 20 by means of a link system and/or wire (not shown). As set forth hereinabove, the charge value is increased when the corona discharge electrode approaches the surface of insulating layer 1 and is decreased when the electrode moves away from it. Accordingly, motor 19 actuates arm' 20 to move the secondary corona discharge electrode 12 away from insulating layer 1 when the surface potential measured by detector 8 is too large, and to move electrode 12 towards the surface when too small. In this case, the voltage applied to secondary corona discharge electrode 12 may be of a fixed value such as that applied by source 26, and the high voltage transformer circuit shown in FIG. 3 would not be required.
The voltage applied to the first and second corona discharge 7 electrodes may be of direct current. Alternatively, direct and alternate currents may be used together.
Although the embodiments described hereinabove only Although the member to be charged has been generally characterized as an electrophotographic layer overlying a conductor, the present invention may be utilized with equal facility with an electrically insulating material formed on a conductive support. For example, a layer of plastic formed on a conductive support may be uniformly and efficiently charged with the apparatus of the present invention.
While the invention has been described with reference to its preferred embodiments, it will be understood by those skilled in the art that various changes may be made and equivalents may be substituted for elements thereof without departing from the true spirit and scope of the invention. In addition, many modifications may be made to adapt a particular situation or material to the teachings of the invention without departing from its essential teachings.
What is claimed is:
1. Apparatus for uniformly charging the surface of an insulating member to a predetermined charge magnitude comprising:
means for charging a portion of said insulating member to a charge magnitude less than said predetermined charge magnitude by a first corona discharge electrode, means for transporting said charged portion of said insulating member towards a second corona discharge electrode spaced-apart from said first corona discharge electrode,
means for generating a signal representing the amount of charge deposited on said insulating member portion as said charged portion moves toward said second spacedapart corona discharge electrode,
means for delaying said generated sigrnal for a time sufficient to enable said charged portion of said insulating member to be charged by said second corona discharge electrode,
means for comparing said delayed generated signal with a signal representing said predetermined charge magnitude and generating a difi'erent signal as a result thereof, and means for applying said difference signal to said second corona discharge electrode whereby the charged portion of said insulating member is charged substantially uniformly to said predetermined charge magnitude.
2. Apparatus as defined in claim 1 wherein screen grids are disposed between said corona discharge electrodes and the surface of said insulating member.
3. Apparatus as defined in claim 2 wherein said delayed signal is applied to the screen grid adjacent to said second corona discharge electrode whereby the amount of charge generated thereby is controlled.
4. Apparatus for uniformly charging the surface of an insulating member to a predetermined charge magnitude comprising:
means for charging a portion of said insulating member to a charge magnitude less than said predetermined charge magnitude by a first corona discharge electrode, means for transporting said charged portion of said insulating member towards a second corona discharge electrode spaced-apart from said first corona discharge electrode,
means for generating a signal representing the amount of charge deposited on said insulating member portion as said charged portion moves toward said second spacedapart corona discharge electrode,
means for delaying said generated signal for a time suffrcient to enable said charged portion of said insulating member to be charged by said second corona discharge electrode,
means for comparing said delayed generated signal with a signal representing said predetermined charge magrnitude and generating a difierence signal as a result thereof, and means for applying said difference signal to a movable member, said movable member moving said second corona discharge electrode towards and away from the surface of said insulating member in accordance with said difi'erence signal, whereby the charged portion of said insulating member is charged substantially uniformly to said predetermined charge magnitude.

Claims (4)

1. Apparatus for uniformly charging the surface of an insulating member to a predetermined charge magnitude comprising: means for charging a portion of said insulating member to a charge magnitude less than said predetermined charge magnitude by a first corona discharge electrode, means for transporting said charged portion of said insulating member towards a second corona discharge electrode spaced-apart from said first corona discharge electrode, means for generating a signal representing the amount of charge deposited on said insulating member portion as said charged portion moves toward said second spaced-apart corona discharge electrode, means for delaying said generated signal for a time sufficient to enable said charged portion of said insulating member to be charged by said second corona discharge electrode, means for comparing said delayed generated signal with a signal representing said predetermined charge magnitude and generating a different signal as a result thereof, and means for applying said difference signal to said second corona discharge electrode whereby the charged portion of said insulating member is charged substantially uniformly to said predetermined charge magnitude.
2. Apparatus as defined in claim 1 wherein screen grids are disposed between said corona discharge electrodes and the surface of said insulating member.
3. Apparatus as defined in claim 2 wherein said delayed signal is applied to the screen grid adjacent to said second corona discharge electrode whereby the amount of charge generated thereby is controlled.
4. Apparatus for uniformly charging the surface Of an insulating member to a predetermined charge magnitude comprising: means for charging a portion of said insulating member to a charge magnitude less than said predetermined charge magnitude by a first corona discharge electrode, means for transporting said charged portion of said insulating member towards a second corona discharge electrode spaced-apart from said first corona discharge electrode, means for generating a signal representing the amount of charge deposited on said insulating member portion as said charged portion moves toward said second spaced-apart corona discharge electrode, means for delaying said generated signal for a time sufficient to enable said charged portion of said insulating member to be charged by said second corona discharge electrode, means for comparing said delayed generated signal with a signal representing said predetermined charge magnitude and generating a difference signal as a result thereof, and means for applying said difference signal to a movable member, said movable member moving said second corona discharge electrode towards and away from the surface of said insulating member in accordance with said difference signal, whereby the charged portion of said insulating member is charged substantially uniformly to said predetermined charge magnitude.
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Cited By (18)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3873895A (en) * 1973-12-05 1975-03-25 Xerox Corp Technique for charging dielectric surfaces to high voltage
US3939386A (en) * 1975-01-30 1976-02-17 Xerox Corporation Technique for charging dielectric surfaces to high voltage
US3950680A (en) * 1975-04-28 1976-04-13 Xerox Corporation Electrostatographic diagnostics system
US4135085A (en) * 1977-08-10 1979-01-16 The Continental Group, Inc. Charging device for basecoat charging of can ends
FR2397663A1 (en) * 1977-07-11 1979-02-09 Canon Kk METHOD AND APPARATUS FOR ADJUSTING THE QUALITY OF ELECTROPHOTOGRAPHIC IMAGE
US4167325A (en) * 1977-11-07 1979-09-11 James River Graphics Inc. Electrographic recording apparatus
US4245272A (en) * 1979-04-30 1981-01-13 Eastman Kodak Company Apparatus and method for low sensitivity corona charging of a moving photoconductor
US4348711A (en) * 1979-07-06 1982-09-07 The Post Office Method and apparatus for implanting a charge in an electret foil
US4408865A (en) * 1981-11-23 1983-10-11 Hewlett Packard Company Corona discharge device for electrophotographic charging and potential leveling
US4411514A (en) * 1979-04-24 1983-10-25 Canon Kabushiki Kaisha Variable magnification electrophotographic copying apparatus
US4417804A (en) * 1981-06-19 1983-11-29 Xerox Corporation High voltage comparator for photoreceptor voltage control
EP0108644A1 (en) * 1982-11-08 1984-05-16 Xerox Corporation A charge control apparatus
US4454559A (en) * 1982-08-30 1984-06-12 Xerox Corporation Control for a corona discharge device
US4480909A (en) * 1980-03-13 1984-11-06 Canon Kabushiki Kaisha Potential control on photosensitive member
US4507373A (en) * 1983-10-03 1985-03-26 Eastman Kodak Company Method and apparatus for uniformly charging a surface
US4618249A (en) * 1985-06-10 1986-10-21 Eastman Kodak Company Corona-charging apparatus
US5412212A (en) * 1993-12-06 1995-05-02 Eastman Kodak Company Corona-charging apparatus and method
US9726999B2 (en) * 2014-12-03 2017-08-08 Canon Kabushiki Kaisha Image forming apparatus

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US3013203A (en) * 1958-07-01 1961-12-12 Xerox Corp Xerographic electrometer apparatus
US3582731A (en) * 1968-07-29 1971-06-01 Xerox Corp Charging system
US3586908A (en) * 1969-02-28 1971-06-22 Robert E Vosteen Automatic potential control system for electrophotography apparatus
US3604925A (en) * 1968-12-03 1971-09-14 Zerox Corp Apparatus for controlling the amount of charge applied to a surface

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US3013203A (en) * 1958-07-01 1961-12-12 Xerox Corp Xerographic electrometer apparatus
US3582731A (en) * 1968-07-29 1971-06-01 Xerox Corp Charging system
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Cited By (18)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3873895A (en) * 1973-12-05 1975-03-25 Xerox Corp Technique for charging dielectric surfaces to high voltage
US3939386A (en) * 1975-01-30 1976-02-17 Xerox Corporation Technique for charging dielectric surfaces to high voltage
US3950680A (en) * 1975-04-28 1976-04-13 Xerox Corporation Electrostatographic diagnostics system
FR2397663A1 (en) * 1977-07-11 1979-02-09 Canon Kk METHOD AND APPARATUS FOR ADJUSTING THE QUALITY OF ELECTROPHOTOGRAPHIC IMAGE
US4135085A (en) * 1977-08-10 1979-01-16 The Continental Group, Inc. Charging device for basecoat charging of can ends
US4167325A (en) * 1977-11-07 1979-09-11 James River Graphics Inc. Electrographic recording apparatus
US4411514A (en) * 1979-04-24 1983-10-25 Canon Kabushiki Kaisha Variable magnification electrophotographic copying apparatus
US4245272A (en) * 1979-04-30 1981-01-13 Eastman Kodak Company Apparatus and method for low sensitivity corona charging of a moving photoconductor
US4348711A (en) * 1979-07-06 1982-09-07 The Post Office Method and apparatus for implanting a charge in an electret foil
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