US3909614A - Scorotron power supply circuit - Google Patents

Scorotron power supply circuit Download PDF

Info

Publication number
US3909614A
US3909614A US510336A US51033674A US3909614A US 3909614 A US3909614 A US 3909614A US 510336 A US510336 A US 510336A US 51033674 A US51033674 A US 51033674A US 3909614 A US3909614 A US 3909614A
Authority
US
United States
Prior art keywords
current
shield
grid
corona
scorotron
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
US510336A
Inventor
Richard C Marshall
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.)
Xerox Corp
Original Assignee
Xerox Corp
Priority date (The priority date 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 date listed.)
Filing date
Publication date
Application filed by Xerox Corp filed Critical Xerox Corp
Application granted granted Critical
Publication of US3909614A publication Critical patent/US3909614A/en
Anticipated expiration legal-status Critical
Expired - Lifetime legal-status Critical Current

Links

Images

Classifications

    • 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
    • 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

  • a scorotron for umformly charging an electrostatographic copying photoconductive surface has a coro [2]] Appl. No: 510,336 node wire, a conductive metal shield and a screen grid.
  • the coronode wire is supplied through a stabilizing resistor from an electrical inverter.
  • the screen and [30] Foreign Apphc auon pnonty Data the shield are connected together and commonly con- Umtcd Kmgdom 59538/73 nected to ground through two series connected resistors. From a connection point between the two resis- [52] US.
  • This invention relates to electrostatography. More particularly this invention relates to electrical circuitry for controlling acorona generating device applying electrostatic charge onto a suitable surface, such as a xerographic imaging plate.
  • the charging of the electrostatographic plate in preparationfor the exposure step can be accomplished by means of a corona generating device whereby electrostatic charge is applied to the electrostatographic plate to raise it to a potential of approximately 500 to 600 volts.
  • a corona generating device for this purpose is disclosed in the Walkup U.S. Pat. No. 2,777,957 wherein a plurality of parallel wires are connected in series to a high voltage source and are supported in a conductive shield that is arranged in closely spaced relation to the surface to be charged. When the wires are energized, corona is generated along the surface of the wires and ionsare caused to be deposited on the adjacent photoconductive surface.
  • Suitable means are usually provided to effect relative movement of the surface to be charged and the corona generating device.
  • a biased wire screen placed between the corona wires and the electrostatographic plate permits energizing the corona wires to a potential well above the corona threshold potential thereof without causing damage to the electrostatographic plate because the excess of corona current over that required for proper charging ofthe plate is drained offby' thebiased screen.
  • This type of corona generating device is referred to in the art as scorotron.
  • the corona threshold potential and the corona current from an energized wire are functions of the wire diameter, i.e., the corona threshold increases and the corona current for any given potential decreases as the wire diameter is increased. Variations inthe potential applied to corona wires ofa given diameter will cause relatively large changes in corona current with corresponding variations in the charging rate. In addition. the coronathresh'old potential and corona current are also affected directly by deposits of dust that may. accumulate on the wire and by variations of movement and ionized conditions of the air sheath surrounding the wire.
  • the contrast value, comparable to the contrast values obtained from silver halide papers, of the electrostatic latent image may be related directly to the potential charge on the electrostatographic plate before exposure, it is apparent that if the plate is not uniformly charged over its entire area, the contrast value of the electrostatic latent image obtained upon exposure will vary in different areas on the plate, and a mottled effect will be visible on the image when developed.
  • a prior art improved scorotron device whereby a uniform electrostatic charge can be deposited on the electrostatographic plate is disclosed in the Codichini U.S. Pat. No. 3,062,956.
  • the scorotron device described therein consists of a backup shield, corona generating electrode wires called the coronode, and screen wires.
  • the coronode wires by corona discharge, charging the photoconductive surface of the electrostatographic plate.
  • the potential applied to the plate surface is varied by changing the screen potential.
  • the charging circuit contains a current stabilizer and a regulated direct current power supply.
  • the current stabilizer is a device for controlling charging current by automatically adjusting the screen potential when a change is sensed in the current being supplied to the coronode.
  • any change in the charging current from the coronodes to the electrostatographic plate produces a change in the applied voltage to a control valve, for example, a high gain pentode, the output of said control valve being applied to the screen wires of the scorotron device.
  • a control valve for example, a high gain pentode
  • the output of said control valve being applied to the screen wires of the scorotron device.
  • any change in the charging current from the coronodes to the electrostatographic surface results in a change in the control valve resistance which, in turn, produces a change in the screen potential.
  • the resistance of the control valve increases thereby increasing the screen voltage to permit the charging current to increase back to its desired value and, of course, the converse is true as the charging current increases above a desired value.
  • the charging current can be maintained at a substantially constant value and is not adversely affected by any of the normal variables such as dirty wires, atmospheric changes, etc., which otherwise would affect the magnitude of the charging current.
  • scorotron power supply arrangement comprising an electrical, power supply means and circuit means arranged to sense the voltage at the grid and to supply control signals in de pendence thereon to adjust the power supply to alter the current supply to the coronode in a manner to maintain said voltage substantially constant.
  • the FIGURE here illustrates a scorotron supply arrangement according to the present invention, by way of example, in which a schematic circuit diagram of the arrangement is shown. 3
  • a scorotron has a coronode wire 11, and a conductive metal shield 12 directly electrically connected to a screen 13.
  • the coronode wire 11 is connected to be supplied through a stabilizing resistor 14 from a conventional inverter 15.
  • the screen 13 is connected through series connected resistors 16 and 17, to ground. From a point between the resistors 16 and 17 a feed-back loop is provided to supply signals to a conventional regulator 18 connected at the input side of the inverter 15.
  • the inverter is supplied from a transformer 19 through a rectifier bridge network 20.
  • a smoothing capacitor 21 is connected across the bridge network 20.
  • the current is supplied from the inverter output to the coronode wire 11 and corona discharge takes place as has been explained.
  • the grid voltage is required to be kept substantially constant at a predetermined value.
  • Theshield l2 and the screen 13 collect excess ions liberated at the surface of the coronode wire 11 to produce currents in the shield 12 and screen 13. The summation. of these currents,
  • biasing current flows through the resistors 16 and 17 to ground.
  • the biasing current in the described embodiment is maintained substantially constant, for maintaining the grid voltage substantially constant, by feeding, via the feed-back loop, a voltage signal generated by the biasing current to the regulator 18 to adjust the inverter output current to increase or decrease as the case may be. Whenever the voltage in the feed-back loop drops the output current is increased to raise thevoltage to its predetermined level. Similarly, if the voltage in the feed-back loop rises the output current is reduced by action of the regulator 18.
  • the surface to be charged charges up to a voltage substantially equal to the grid voltage provided that sufficient ions are liberated by the corona discharge.
  • the scorotron is capable of producing sufficient ions per unit time to charge up a moving surface, of a photoreceptor say, to becharged and that the power supply to the scorotron can supply sufficient current to cause release of those ions.
  • the present invention we control the charging of the surface to' be charged by maintaining the grid potential constant. This is acheived by altering the coronode current as and when required.
  • We monitor the grid voltage by measuring the current flowing through a resistor from the grid and made such adjustments automatically using the circuit means.
  • the g'rid current is found to be a substantially fixed ratio, duringnormal use of the coronode current so that by monitoring the grid voltage linearly, related adjustments of the coronode current are made.
  • the charging of the surface to be charged was controlled by altering the coronode current. This was achieved, however, by varying the grid potential, one such arrangement has already been mentioned above incorporating a pentode valve supply circuit.
  • the present invention provides scorotron supply arrangements which are comparatively insensitive to variations of surface speed, from either side of an optimum speed, of the surface to be charged.
  • the supply arrangements of the present invention can be provided using a small number of electrical components.
  • scorotron corona charging apparatus for charging a surface
  • said scorotron includes a conductive shield a conductive control grid and at least one corona emitting electrode
  • said improvement in said scorotron charging apparatus comprising:
  • adjustable electrical power supply means connected to said corona emitting electrode to provide a current supply thereto; sensing circuit means, including resistor means, for
  • sensing a voltage produced on said grid by said corona emitting electrode said sensing circuit means being connected to said power supply means to supply a control signal to said power supply means proportional to said voltage produced on said grid from said corona emitting electrode, said control signal from said sensing circuit means controlling said current supply from said power supply to said corona emitting electrode to main- .tain said voltage at said grid substantially constant, wherein said conductive control grid and said conductive shield are directly electrically connected together and to said resistor means of said sensing current means,
  • the copying apparatus of claim 1 further including regulator means connected to said resistor means, and inverter means connected between said regulator means and said corona emitting electrode.
  • a scorotron for uniformly charging an electrostatographic copying photoconductive surface comprising a corona emitting coronode wire, a conductive metal shield and a conductive screen grid, wherein the coronode wire is electrically supplied from a regulator,

Abstract

A scorotron for uniformly charging an electrostatographic copying photoconductive surface has a coronode wire, a conductive metal shield and a screen grid. The coronode wire is supplied through a stabilizing resistor from an electrical inverter. The screen and the shield are connected together and commonly connected to ground through two series connected resistors. From a connection point between the two resistors a feed-back loop is provided to supply feed-back signals to a regulator connected at the input of the inverter, which feed-back signals are indicative of the sum of the screen and shield currents from the coronode wire corona emission, but insensitive to proportional changes between the screen current and the shield current.

Description

United States Patent [1 1 1 3,909,614
Marshall Sept. 30, 1975 SCOROTRON POWER SUPPLY CIRCUIT 3,819.942 6/1974 Hastwell 250/324 [75] Inventor: Richard C. Marshall, Harpcndcn, v
England Primary E.\'ammerCra1g E. Church [73] Assignee: 22:10: Corporation, Stamford, ABSTRACT Filed: m 1974 A scorotron for umformly charging an electrostatographic copying photoconductive surface has a coro [2]] Appl. No: 510,336 node wire, a conductive metal shield and a screen grid. The coronode wire is supplied through a stabilizing resistor from an electrical inverter. The screen and [30] Foreign Apphc auon pnonty Data the shield are connected together and commonly con- Umtcd Kmgdom 59538/73 nected to ground through two series connected resistors. From a connection point between the two resis- [52] US. Cl; 250/324; 317/262 A tors a feedback loop is provided to Supply feedback [51] hit. Cl. G03G 15/00 signals to a regulator Connected at the input of the [58] Fleld of Search 250/324, 325,326; verter; which feed back Signals are indicative of the 317/262 A sum of the screen and shield currents from the coronode wire corona emission, but insensitive to propor- [56] References C'ted tional changes between the screen current and the UNITED STATES PATENTS shield current.
3,068,356 12/1962 Codichini 250/326 3 699 388 10 1972 Ukai 317/262 A 3 Clams 1 Drawmg figure US. Patent Sept. 30,1975
1 SCOROTRON POWER SUPPLY CIRCUIT This invention relates to electrostatography. More particularly this invention relates to electrical circuitry for controlling acorona generating device applying electrostatic charge onto a suitable surface, such as a xerographic imaging plate.
The basic electrostatographic process is disclosed in the Carlson U.S. Pat. No. 2,297,691. in this process an electrostatographic plate comprising a photoconductive insulating material on a conductive backing is given a uniform electric charge over its surface and is then exposed to the subject matter tobe reproduced usually by conventional projection techniques. This exposure discharges the plate areas in accordance with the radiationintensity which reaches them and thereby creates an electrostatic latent image on or in the plate coating which may then be developed with an electroscopic material which electrostatically clings to the plate in a visual pattern corresponding to the electrostatic image. Thereafter the developed image usually transferred to a support material to which it may be fixed by any suitable means.
The charging of the electrostatographic plate in preparationfor the exposure step can be accomplished by means of a corona generating device whereby electrostatic charge is applied to the electrostatographic plate to raise it to a potential of approximately 500 to 600 volts. One form of corona generating device for this purpose is disclosed in the Walkup U.S. Pat. No. 2,777,957 wherein a plurality of parallel wires are connected in series to a high voltage source and are supported in a conductive shield that is arranged in closely spaced relation to the surface to be charged. When the wires are energized, corona is generated along the surface of the wires and ionsare caused to be deposited on the adjacent photoconductive surface. Suitable means are usually provided to effect relative movement of the surface to be charged and the corona generating device. A biased wire screen placed between the corona wires and the electrostatographic plate permits energizing the corona wires to a potential well above the corona threshold potential thereof without causing damage to the electrostatographic plate because the excess of corona current over that required for proper charging ofthe plate is drained offby' thebiased screen. This type of corona generating device is referred to in the art as scorotron.
As is well known, the corona threshold potential and the corona current from an energized wire are functions of the wire diameter, i.e., the corona threshold increases and the corona current for any given potential decreases as the wire diameter is increased. Variations inthe potential applied to corona wires ofa given diameter will cause relatively large changes in corona current with corresponding variations in the charging rate. In addition. the coronathresh'old potential and corona current are also affected directly by deposits of dust that may. accumulate on the wire and by variations of movement and ionized conditions of the air sheath surrounding the wire. Thus, when operating at the corona threshold, minute differences in wire'diameter, slight accumulations of dust on the wire and variations in air temperature or in the air pressure, i.e., ambient conditions, can drastically affect the corona generating capability of the wire causing non-uniform electrostatic charge to be deposited on the electrostatographic plate.
It has heretofore been established that consistent high quality reproductions can best be obtained when uniform potential is applied to the electrostatographic plate in preparation of the plate for the exposure step. If the electrostatographic plate is not charged to a sufficient potential, the electrostatic latent image obtained upon exposure will be relatively weak and the resulting deposition of an electroscopic material thereon will be correspondingly small. If, however, the electrostatographic plate is overcharged, the converse will occur, and if over-charged sufficiently, the photoconductive layer of the electrostatographic plate can be permanently damaged.
Since the contrast value, comparable to the contrast values obtained from silver halide papers, of the electrostatic latent image may be related directly to the potential charge on the electrostatographic plate before exposure, it is apparent that if the plate is not uniformly charged over its entire area, the contrast value of the electrostatic latent image obtained upon exposure will vary in different areas on the plate, and a mottled effect will be visible on the image when developed.
A prior art improved scorotron device whereby a uniform electrostatic charge can be deposited on the electrostatographic plate is disclosed in the Codichini U.S. Pat. No. 3,062,956. The scorotron device described therein consists of a backup shield, corona generating electrode wires called the coronode, and screen wires. The coronode wires, by corona discharge, charging the photoconductive surface of the electrostatographic plate. The potential applied to the plate surface is varied by changing the screen potential. To ensure a constant charging current during operation at any given contrast setting, the charging circuit contains a current stabilizer and a regulated direct current power supply. The current stabilizer is a device for controlling charging current by automatically adjusting the screen potential when a change is sensed in the current being supplied to the coronode.
In operation in the Codichini circuit, any change in the charging current from the coronodes to the electrostatographic plate produces a change in the applied voltage to a control valve, for example, a high gain pentode, the output of said control valve being applied to the screen wires of the scorotron device. In this manner, any change in the charging current from the coronodes to the electrostatographic surface results in a change in the control valve resistance which, in turn, produces a change in the screen potential. With this circuit, as a decrease in charging current occurs, the resistance of the control valve increases thereby increasing the screen voltage to permit the charging current to increase back to its desired value and, of course, the converse is true as the charging current increases above a desired value. in this manner, by altering the screen voltage, the charging current can be maintained at a substantially constant value and is not adversely affected by any of the normal variables such as dirty wires, atmospheric changes, etc., which otherwise would affect the magnitude of the charging current.
Various other relevant corotron or scorotron current control arrangements are known in the art. The following additionally noted U.S. Patents are listed as exemplary: U.S. Pat. No. 2,956,487 to E. C. Giaimo, Jr., (RCA), U.S. Pat. No. 3,335,275 to P. F. King (Xerox),
U.S. Pat. No. 3,688,107 to J. M. Schneider et al (Xerox), US. Pat. No. 3,699,388 (Ricoh) (and its related U.K'. Pat. No. 1,235,497), and U.S. Pat.No. 3,805,069 to D. H. Fisher (Xerox), and U.S. Pat. No. 3,813,548 to M. Silverberg (Xerox).
In the present invention there is a scorotron power supply arrangement comprising an electrical, power supply means and circuit means arranged to sense the voltage at the grid and to supply control signals in de pendence thereon to adjust the power supply to alter the current supply to the coronode in a manner to maintain said voltage substantially constant.
The FIGURE here illustrates a scorotron supply arrangement according to the present invention, by way of example, in which a schematic circuit diagram of the arrangement is shown. 3
Referring to the FIGURE, a scorotron has a coronode wire 11, and a conductive metal shield 12 directly electrically connected to a screen 13. The coronode wire 11 is connected to be supplied through a stabilizing resistor 14 from a conventional inverter 15. The screen 13 is connected through series connected resistors 16 and 17, to ground. From a point between the resistors 16 and 17 a feed-back loop is provided to supply signals to a conventional regulator 18 connected at the input side of the inverter 15. v
The inverter is supplied from a transformer 19 through a rectifier bridge network 20. A smoothing capacitor 21 is connected across the bridge network 20.
In use, the current is supplied from the inverter output to the coronode wire 11 and corona discharge takes place as has been explained. In order to maintain uniform depositing of ions on the photoconductive surface to provide in turn uniform charging of the surface, the grid voltage is required to be kept substantially constant at a predetermined value. Theshield l2 and the screen 13 collect excess ions liberated at the surface of the coronode wire 11 to produce currents in the shield 12 and screen 13. The summation. of these currents,
hereinafter referred to as the biasing current, flows through the resistors 16 and 17 to ground.
The biasing current in the described embodiment is maintained substantially constant, for maintaining the grid voltage substantially constant, by feeding, via the feed-back loop, a voltage signal generated by the biasing current to the regulator 18 to adjust the inverter output current to increase or decrease as the case may be. Whenever the voltage in the feed-back loop drops the output current is increased to raise thevoltage to its predetermined level. Similarly, if the voltage in the feed-back loop rises the output current is reduced by action of the regulator 18.
The surface to be charged charges up to a voltage substantially equal to the grid voltage provided that sufficient ions are liberated by the corona discharge. In the described arrangement, we ensure that the scorotron is capable of producing sufficient ions per unit time to charge up a moving surface, of a photoreceptor say, to becharged and that the power supply to the scorotron can supply sufficient current to cause release of those ions. 7
Typically using a selenium coated photoreceptor approximately 25'cms long, we charge the surface up to 650 volts using a scorotron of the type schematically illustrated in the drawing. The surface speedof the photoreceptor is 4.8 inches per second and is separated from the grid by 1.65 millimeters. The coronode voltage and current. are 5,700 voltsand l milliamps and the biasing current is 151 milliamps. In the specific embodiments, we choose the circuit parameters such that for the typical values above the voltage at the connec tion between resistors 16 and 17 is about 4 volts.
It will be noted that according to the present invention we control the charging of the surface to' be charged by maintaining the grid potential constant. This is acheived by altering the coronode current as and when required. We monitor the grid voltage by measuring the current flowing through a resistor from the grid and made such adjustments automatically using the circuit means. In a scorotron of the type described, the g'rid current is found to be a substantially fixed ratio, duringnormal use of the coronode current so that by monitoring the grid voltage linearly, related adjustments of the coronode current are made.
In some prior art arrangements, the charging of the surface to be charged was controlled by altering the coronode current. This was achieved, however, by varying the grid potential, one such arrangement has already been mentioned above incorporating a pentode valve supply circuit. In the present inventors experience such arrangements, in which the grid voltage is altered as a controlling adjustment, are more speed dependent than embodiments of the present invention. In other words, the present invention provides scorotron supply arrangements which are comparatively insensitive to variations of surface speed, from either side of an optimum speed, of the surface to be charged. Also, the supply arrangements of the present invention can be provided usinga small number of electrical components. 3
While a particular embodiment of the invention has been described above, it will be appreciated that various modifications may be made by one skilled in the art without departing from the scope of the invention as defined in the following claims.
What is claimed is:
I. In electrostatographic copying apparatus including scorotron corona charging apparatus for charging a surface, wherein said scorotron includes a conductive shield a conductive control grid and at least one corona emitting electrode, the improvement in said scorotron charging apparatus comprising:
adjustable electrical power supply means connected to said corona emitting electrode to provide a current supply thereto; sensing circuit means, including resistor means, for
sensing a voltage produced on said grid by said corona emitting electrode, said sensing circuit means being connected to said power supply means to supply a control signal to said power supply means proportional to said voltage produced on said grid from said corona emitting electrode, said control signal from said sensing circuit means controlling said current supply from said power supply to said corona emitting electrode to main- .tain said voltage at said grid substantially constant, wherein said conductive control grid and said conductive shield are directly electrically connected together and to said resistor means of said sensing current means,
said resistor means conducting the combined total current frorn said control grid and said conductive shield therethrough,
said combined total current through said resistive means providing said control signal to said power supply means.
2. The copying apparatus of claim 1 further including regulator means connected to said resistor means, and inverter means connected between said regulator means and said corona emitting electrode.
3. ln a scorotron for uniformly charging an electrostatographic copying photoconductive surface comprising a corona emitting coronode wire, a conductive metal shield and a conductive screen grid, wherein the coronode wire is electrically supplied from a regulator,
tween the screen grid current and the shield current.

Claims (3)

1. In electrostatographic copying apparatus including scorotron corona charging apparatus for charging a surface, wherein said scorotron includes a conductive shield a conductive control grid and at least one corona emitting electrode, the improvement in said scorotron charging apparatus comprising: adjustable electrical power supply means connected to said corona emitting electrode to provide a current supply thereto; sensing circuit means, including resistor means, for sensing a voltage produced on said grid by said corona emitting electrode, said sensing circuit means being connected to said power supply means to supply a control signal to said power supply means proportional to said voltage produced on said grid from said corona emitting electrode, said control signal from said sensing circuit means controlling said current supply from said power supply to said corona emitting electrode to maintain said voltage at said grid substantially constant, wherein said conductive control grid and said conductive shield are directly electrically connected together and to said resistor means of said sensing current means, said resistor means conducting the combined total current from said control grid and said conductive shield therethrough, said combined total current through said resistive means providing said control signal to said power supply means.
2. The copying apparatus of claim 1 further including regulator means connected to said resistor means, and inverter means connected between said regulator means and said corona emitting electrode.
3. In a scorotron for uniformly charging an electrostatographic copying photoconductive surface comprising a corona emitting coronode wire, a conductive metal shield and a conductive screen grid, wherein the coronode wire is electrically supplied from a regulator, the improvement wherein the screen grid and the shield are connected together and commonly connected to ground through at least two series connected resistors having a connection point therebetween and a feed-back loop is provided connecting feed-back signals from this connection point to the regulator, which feed-back signals correspond to the sum of the screen and shield currents from the coRonode wire corona emission and are insensitive to proportional changes between the screen grid current and the shield current.
US510336A 1973-12-21 1974-09-30 Scorotron power supply circuit Expired - Lifetime US3909614A (en)

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
GB5953873A GB1451647A (en) 1973-12-21 1973-12-21

Publications (1)

Publication Number Publication Date
US3909614A true US3909614A (en) 1975-09-30

Family

ID=10483953

Family Applications (1)

Application Number Title Priority Date Filing Date
US510336A Expired - Lifetime US3909614A (en) 1973-12-21 1974-09-30 Scorotron power supply circuit

Country Status (3)

Country Link
US (1) US3909614A (en)
CA (1) CA1034640A (en)
GB (1) GB1451647A (en)

Cited By (12)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US4077709A (en) * 1975-08-26 1978-03-07 Xerox Corporation Transfer charge control system
US4227233A (en) * 1976-10-01 1980-10-07 Olympus Optical Company Limited Corona discharge device for electrographic apparatus
US4456825A (en) * 1976-05-26 1984-06-26 Canon Kabushiki Kaisha Method of and device for charging by corona discharge
JPS6035760A (en) * 1983-08-06 1985-02-23 Ricoh Co Ltd Control device for electrostatically charged potential of photosensitive body
JPS6055362A (en) * 1983-09-07 1985-03-30 Ricoh Co Ltd Controller for electrostatic charging potential of photosensitive body
US4591713A (en) * 1984-01-03 1986-05-27 Xerox Corporation Efficient, self-limiting corona device for positive or negative charging
JPH03279973A (en) * 1990-03-28 1991-12-11 Murata Mfg Co Ltd High voltage power source circuit for electrostatic charger
US5105330A (en) * 1989-05-26 1992-04-14 Brother Kogyo Kabushiki Kaisha Scorotron type charging apparatus
US5907155A (en) * 1998-01-08 1999-05-25 Xerox Corporation Constant DC offset coronode voltage tracking circuit
US20080290276A1 (en) * 2007-05-22 2008-11-27 Xerox Corporation Dicorotron having adjustable wire height
US20120069485A1 (en) * 2010-09-19 2012-03-22 Yefim Riskin Method and device for automatic positive and negative ion balance control in a bipolar ion generator
US9843169B2 (en) 2015-01-21 2017-12-12 Filt Air Ltd Bipolar ionizer with external ion imbalance indicator

Citations (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3068356A (en) * 1960-06-15 1962-12-11 Xerox Corp Xerographic charging apparatus
US3699388A (en) * 1967-07-06 1972-10-17 Ricoh Kk Apparatus for electrostatic charging of paper in electrophotographic reproduction
US3819942A (en) * 1973-05-07 1974-06-25 Savin Business Machines Corp Regulated power supply for corona charging unit

Patent Citations (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3068356A (en) * 1960-06-15 1962-12-11 Xerox Corp Xerographic charging apparatus
US3699388A (en) * 1967-07-06 1972-10-17 Ricoh Kk Apparatus for electrostatic charging of paper in electrophotographic reproduction
US3819942A (en) * 1973-05-07 1974-06-25 Savin Business Machines Corp Regulated power supply for corona charging unit

Cited By (16)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US4077709A (en) * 1975-08-26 1978-03-07 Xerox Corporation Transfer charge control system
US4456825A (en) * 1976-05-26 1984-06-26 Canon Kabushiki Kaisha Method of and device for charging by corona discharge
US4227233A (en) * 1976-10-01 1980-10-07 Olympus Optical Company Limited Corona discharge device for electrographic apparatus
JPS6035760A (en) * 1983-08-06 1985-02-23 Ricoh Co Ltd Control device for electrostatically charged potential of photosensitive body
JPH0675222B2 (en) 1983-08-06 1994-09-21 株式会社リコー Charger control device for photoconductor
JPH0673042B2 (en) 1983-09-07 1994-09-14 株式会社リコー Charger control device for photoconductor
JPS6055362A (en) * 1983-09-07 1985-03-30 Ricoh Co Ltd Controller for electrostatic charging potential of photosensitive body
US4591713A (en) * 1984-01-03 1986-05-27 Xerox Corporation Efficient, self-limiting corona device for positive or negative charging
US5105330A (en) * 1989-05-26 1992-04-14 Brother Kogyo Kabushiki Kaisha Scorotron type charging apparatus
JPH03279973A (en) * 1990-03-28 1991-12-11 Murata Mfg Co Ltd High voltage power source circuit for electrostatic charger
US5907155A (en) * 1998-01-08 1999-05-25 Xerox Corporation Constant DC offset coronode voltage tracking circuit
US20080290276A1 (en) * 2007-05-22 2008-11-27 Xerox Corporation Dicorotron having adjustable wire height
US7763853B2 (en) * 2007-05-22 2010-07-27 Xerox Corporation Dicorotron having adjustable wire height
US20120069485A1 (en) * 2010-09-19 2012-03-22 Yefim Riskin Method and device for automatic positive and negative ion balance control in a bipolar ion generator
US8611065B2 (en) * 2010-09-19 2013-12-17 Yefim Riskin Method and device for automatic positive and negative ion balance control in a bipolar ion generator
US9843169B2 (en) 2015-01-21 2017-12-12 Filt Air Ltd Bipolar ionizer with external ion imbalance indicator

Also Published As

Publication number Publication date
GB1451647A (en) 1976-10-06
CA1034640A (en) 1978-07-11

Similar Documents

Publication Publication Date Title
US3909614A (en) Scorotron power supply circuit
US4055380A (en) Transfer charge maintaining system
US3961193A (en) Self adjusting corona device
US5223668A (en) Single component developing device with velocity of roller dependent on time constant of circuit formed by resistor layer of developer carrying member and photosensitive drum
US3062956A (en) Xerographic charging apparatus
US4618249A (en) Corona-charging apparatus
CA1123041A (en) Apparatus and method for low sensitivity corona charging of a moving photoconductor
EP0342960B1 (en) Electrophotographic system
US3688107A (en) Electrostatographic charging apparatus
US4105324A (en) Electrophotographic apparatus having compensation for rest-run performance variations
JPH06222652A (en) Adjustable scorotron for application of uniform charge potential
JP3474407B2 (en) Image forming apparatus and method
US4139299A (en) Auto-bias developing apparatus
US4228480A (en) Electrophotographic apparatus with improved corona charging
US3976880A (en) Corona stabilization arrangement
US3122634A (en) Controlled charging in xerographic copying apparatus
US3980049A (en) Developing unit for electrophotography
US3068356A (en) Xerographic charging apparatus
US4583835A (en) Image control device for electrophotographic copier
US3976881A (en) Arrangement for stabilizing corona devices
US4088892A (en) Corona charging apparatus and method
US20090052915A1 (en) Constant voltage leveling device for integrated charging system
US3335273A (en) Xerographic charging apparatus with means to terminate the charging cycle when a predetermined charge is obtained
US4194466A (en) Electrophotographic apparatus for developing latent electrostatic charge images
US6034368A (en) AC corona current regulation