US3892481A - Automatic development electrode bias control system - Google Patents

Automatic development electrode bias control system Download PDF

Info

Publication number
US3892481A
US3892481A US479659A US47965974A US3892481A US 3892481 A US3892481 A US 3892481A US 479659 A US479659 A US 479659A US 47965974 A US47965974 A US 47965974A US 3892481 A US3892481 A US 3892481A
Authority
US
United States
Prior art keywords
developer
electrode
potential
image
unit
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
US479659A
Other languages
English (en)
Inventor
Louis F Schaefer
Kenneth W Gardiner
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.)
Savin Corp
Original Assignee
Savin Business Machines 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 Savin Business Machines Corp filed Critical Savin Business Machines Corp
Priority to US479659A priority Critical patent/US3892481A/en
Priority to CA000222749A priority patent/CA1149154A/en
Priority to IT21838/75A priority patent/IT1034714B/it
Priority to GB13269/75A priority patent/GB1483400A/en
Priority to FR7510654A priority patent/FR2280117A1/fr
Priority to DE19752516012 priority patent/DE2516012A1/de
Priority to JP50044879A priority patent/JPS6158829B2/ja
Application granted granted Critical
Publication of US3892481A publication Critical patent/US3892481A/en
Priority to CA000412994A priority patent/CA1154950A/en
Priority to US06/507,958 priority patent/USRE31964E/en
Assigned to FOOTHILL CAPITAL CORPORATION, A CA. CORP. reassignment FOOTHILL CAPITAL CORPORATION, A CA. CORP. ASSIGNMENT OF ASSIGNORS INTEREST. Assignors: SAVIN CORPORATION
Anticipated expiration legal-status Critical
Assigned to SAVIN CORPORATION reassignment SAVIN CORPORATION ASSIGNMENT OF ASSIGNORS INTEREST (SEE DOCUMENT FOR DETAILS). Assignors: FOOTHILL CAPITAL CORPORATION
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
    • G03G15/06—Apparatus for electrographic processes using a charge pattern for developing
    • G03G15/065—Arrangements for controlling the potential of the developing electrode
    • 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
    • G03G15/06—Apparatus for electrographic processes using a charge pattern for developing
    • G03G15/10—Apparatus for electrographic processes using a charge pattern for developing using a liquid developer

Definitions

  • ABSTRACT An automatic control system for the bias on a development electrode in which a plurality of groundinsulated, narrow floating electrodes are spaced along a line adjacent the entrance of a liquid developer applicator unit.
  • the floating electrodes relatively scan image areas of the surface of an organic photoconductor carried by a conductive support moving through the developer unit.
  • each floating electrode Owing to conduction of a charge from the photoconductive surface through the developer liquid to thecfloating electrodes, they assume potentials each of which is a function of the average potential of the image area subtended by the floating electrode.
  • the potential of each floating electrode is sensed by a high input impedance measuring circuit which selects the potential of the lowest value, amplifies the selected potential and applies the amplified voltage to the biasing electrode or electrodes of the developer system.
  • a fully charged and unexposed area of the surface following the image area produces a reverse bias which cleans the biasing electrodes as the fully charged area passes through the developer system.
  • an organic photoconductor retains a significant charge in background or non-image areas after normal exposure to the copy to be reproduced.
  • This background level may be in the range of from about 100 to about 200 volts.
  • the developer station be provided with a biasing electrode to which a potential is applied to counteract the effect of the residual potential in background areas.
  • a biasing potential should be applied to the electrode only during the period of time during which the latent image is passing through the developer system. If the biasing potential is not switched off, relatively great amounts of toner will be deposited on the biasing electrode when uncharged areas of the drum pass through the developer station.
  • Coriale U.S. Pat. No. 3,6l 1,982 shows an arrangement in which a capacitive probe, located outside and just before the developer unit, is exposed by a shutter to a charged and fully exposed strip at the edge of the photoconductor drum. The sensed potential is amplified and is used to control a variable power source which provides the biasing potential of the electrode located in the developer system.
  • a bias voltage control system is shown in Coriale U.S. Pat. No.
  • the systems of the prior art discussed hereinabove sense photoconductor voltage by the use of delicate and sensitive instruments such as electrometers for measuring the charge in residual areas of the photoconductor.
  • Such instruments are not only expensive, but also involve critical factors such as the particular geometry of the probe and the critical distance of the probe from the surface carrying the potential to be sensed.
  • the arrangements of the prior art moreover, employ switching arrangements for rendering the bias effective only for the period of time during which the image passes through the developer system.
  • owing to the deposition of toner particles on the biasing electrode unless some means is provided for cleaning this electrode, it will rapidly become so contaminated as to render the system inoperative.
  • One object of our invention is to provide an auto matic development electrode bias control system.
  • Another object of our invention is to provide a system for overcoming the effect of background potential which avoids the defects of systems of the prior art intended to achieve this purpose.
  • Another object of our invention is to provide an automatic development electrode bias control system the parameters of which are not critical.
  • Another object of our invention is to provide for automatic exposure control by the automatic bias control to permit high quality copies to be made from both white and colored background originals without requiring operator adjustment.
  • a still further object of our invention is to provide an automatic development electrode bias control system which is relatively inexpensive to manufacture.
  • a still further object of our invention is to provide an automatic development electrode bias control system having means for removing toner particles from the biasing electrode without the use of mechanical cleaning means.
  • our invention contemplates the provision of an automatic development electrode biasing control system for an electrostatic copying machine using a liquid developer in which a plurality of narrow sensing electrodes are spaced along a line in the developer unit adjacent to the entrance thereof. These electrodes afford a measure of the average potential along the image areas subtended by the electrodes owing to conduction of a small portion of the charge on the photoconductive surface through the developer liquid disposed between and in contact with both the surface and with the electrode.
  • the voltages thus sensed are measured by a high input impedance measuring circuit, which selects the potential of lowest value, and amplifies it to provide the biasing voltage for application to the biasing electrodes.
  • FIG. 1 is a partially schematic end elevation of an electrostatic copying machine which may be provided with our automatic development electrode bias control system.
  • FIG. 2 is a perspective view with parts removed, with other parts broken away, and with parts shown in sec tion, illustrating our automatic developmen electrode bias control system.
  • FIG. 3 is a schematic view of one form of an electrical circuit which may be employed in our automatic development electrode bias control system.
  • a machine indicated generally by the reference character 10 includes a drum indicated generally by the reference character 12 made up of a conductive cylinder I4, the outer surface of which carries a layer 16 of organic photoconductive material well known to the art.
  • Drum 12 includes respective end plates 18 and 20 carrying stub shafts 22 and 24 by means of which the drum is mounted for rotary movement in a manner known to the art.
  • a corona discharge unit 26 is adapted to be connected to a suitable source of power 28 through a switch 30 to provide a corona discharge for applying a uniform electrostatic charge to the photoconductor 16 as the drum I2 rotates. After having been charged, the photoconductive surface moves past an exposure unit 32 of any type known to the art, adapted to be connected to a control unit 34 upon the closure of a switch 36.
  • Developer unit 38 may, for example, be of the type which includes an applicator tank 40 disposed within a return tray 42.
  • developer made up of charged toner particles disposed in a carrier liquid having a relatively high volume resistivity is fed into the tank 40 through a pipe 44.
  • the tank 40 fills to a point at which the liquid developer comes into contact with the surface of the drum l2 and then overflows into the tray 42, from whence it is returned to the supply (not shown) through a pipe 46.
  • any means may be employed to control the operation of the various units of the machine 10.
  • a cam 48 on shaft 22 for rotation therewith, so as to actuate a follower 50 to close switch 30 so that a predetermined region around the drum is fully charged.
  • a second cam 54 on shaft 22 is adapted to operate a follower 56 to close switch 36 to place the exposure unit 32 into operation. It will be seen from FIG. 1 that the angular extent of the cam 48 is greater than that of cam 54, so that a greater region of the surface layer 16 is charged than is exposed.
  • the arrangement is such that exposure starts at the beginning of the charged region, so that the fully charged and unexposed region 60 follows the image in the direction of movement of the drum. It will further be appreciated by those skilled in the art that such an arrangement could, if desired, readily be adapted to a system in which the controls are so set as to permit of the making of copies of different lengths.
  • our automatic development electrode bias control system we dispose a small centrally located electrode 62, and edge electrodes 64 and 66 of conductive material in the developer tank 40 adjacent to the entrance thereof. We so locate the electrodes 62, 64 and 66 as to insure that the image area on the drum passes over the electrodes as the image area moves through the developer unit 38. Moreover, the electrodes 62, 64 and 66 are so located that developer liquid flows between the electrodes and the drum and contacts the surfaces of both the electrodes and the drum. Our electrodes 62, 64 and 66 are completely insulated from ground or floating" so that they are permitted to assume their own potentials.
  • each electrode assumes a potential which is a measure of that of an area on the surface of layer 16.
  • the resistance of the toner is high but not a complete insulator.
  • each electrode 62, 64 and 66 will assume a potential which is a measure of the average potential over that portion of the image area which registers with the electrode.
  • the potential the electrode assumes is nearly independent of the electrode-tophotoconductor spacing owing to conductive interconnection by the toner liquid.
  • sensing electrodes 62, 64 and 66 operate on the principle of conduction, rather than capacitance.
  • Electrodes 62, 64 and 66 In order to utilize the potentials sensed by electrodes 62, 64 and 66, we connect the electrodes to a high input impedance measuring circuit 68 which selects as its output the lowest potential sensed.
  • An amplifier 70 which receives its input from the measuring circuit 68 applies a biasing potential to biasing electrodes 72, 74, 76 and 78 in a manner to be described.
  • the average voltage of each electrode 62, 64 and 66 over the image area being sensed thereby will be equal to the residual or background potential in clear areas with no printing and greater than the residual potential in areas with printing.
  • each of the development electrodes 72, 74, 76 and 78 extends across substantially the entire width W of a copy to be produced. Moreover, dimensioning of the sensing electrodes 62, 64 and 66 and the positioning thereof across the width of the copy to be produced are so selected that the electrode 62 scans the central portion of the image which normally corresponds to that part of the original, such as a typewritten page, which contains printing, while the electrodes 64 and 66 scan areas corresponding to margin or border areas of the original which normally are devoid of printing.
  • our arrangement ensures that a minimum bias is provided for most copies.
  • Our circuit 68 also permits of the insertion of a small additional bias to the development electrode to provide an overall bias which is slightly greater than the potential value sensed in a clear area, thus ensuring that no development will take place in the background areas.
  • the resistance of the liquid developer between a sensing electrode and the drum is of the order of ohms.
  • Our high impedance measuring circuit 68 has an input impedance of more than l0 ohms, or at least three orders of magnitude greater than the resistance between the electrode and the drum surface. In this way we are able to obtain a good reading of the average potential along the region of the image area in registry with the electrodes 62.
  • FIG. 3 we have shown one example of a high input impedance measuring circuit indicated generally by the reference character 68, including a sample-and-hold portion to be described hereinbelow and an amplifier indicated generally by the reference character 70, which we may employ in our automatic developer electrode bias control system.
  • a high input impedance measuring circuit indicated generally by the reference character 68, including a sample-and-hold portion to be described hereinbelow and an amplifier indicated generally by the reference character 70, which we may employ in our automatic developer electrode bias control system.
  • shields 80, 82 and 84 for the conductors leading from the sensing electrodes 66, 62 and 64.
  • the high input impedance of the measuring circuit 68 is provided by the transistors 92, 94 and 96. These transistors, in response to the sensed voltages, serve to shunt current away from the base emitter junction of a transistor 106.
  • the common source line 100 which is connected to the base of transistor 106, supplies the base current for the transistor through the resistor 102.
  • a transistor 108 forms a current source for providing the emitter current for transistor I06.
  • the emitter of transistor 106 normally is a few volts more positive than the input to the field effect transistors 92, 94 and 96, assuming that all of these transistors were fed from the same source.
  • the field effect transistors 92, 94 and 96 are fed with input voltages from the respective sensing electrodes 66, 62 and 64.
  • the circuit responds to the least negative of the sensed voltages ignoring the other sensed voltages.
  • a parallel RC circuit coupled the emitter of transistor 106 to the shields 80, 82 and 84, so that the capacitance between the input conductor and the shield does not load the sensing electrode.
  • the negative voltage source of the sensing circuit is a Zener diode 110 connected to the source of -600 volts by a resistor 112.
  • Our measuring circuit 68 includes a sample-and-hold circuit which is responsive to the potential at the common terminal of diode 110 and resistor 112. This signal is applied to the base of a transistor 114 which base is connected to the emitter by means of a diode 116.
  • the collector of transistor 114 is connected to a source of, for example, -300 volts.
  • the transistor 114 forms a low impedance driver which is adapted to apply a potential to a storage capacitor 124.
  • the sample-and-hold circuit includes back-to-back diodes I18 and 120, the common terminal of which is connected to ground and to one terminal of the storage capacitor 124 by a resistor 122.
  • a resistor 128 connects one terminal of switch 126 to the common terminal of diodes I16 and 118. We connect the common terminal of the two switches 126 and 130 to the diode 120. The other terminal of switch 130 is connected to capacitor 124. From the circuit it can be seen that with switch 126 closed transistor 114 is permitted to charge the storage capacitor 124 very rapidly in either direction. Operation of microswitch 130 with switch 126 open permits the capacitor to charge only in the positive direction.
  • switch 126 is closed during the first 2 or 3 centimeters of the copy image and switch I30 is closed for about the first twelve centimeters of the copy image.
  • switch I30 is closed for about the first twelve centimeters of the copy image.
  • a follower 134 positioned at a location around shaft 22 corresponding to that at which the latent image is enteringthe developer system 38, is adapted to be actuated by the earn 132 to close switch 126 and to hold the switch closed for approximately 2 to 3 centimeters of the copy.
  • Another cam 136 on shaft 22 is adapted to actuate a follower 138 located at a position corresponding to that of follower 134 to close switch 130 for approximately the first twelve centimeters of the copy length.
  • transistor 4 is permitted to charge capacitor 124 rapidly in either direction.
  • transistor I14 can charge capacitor 124 only in the positive direction and at a controlled charging rate which is a com promise among a number of factors.
  • a resistor 140 applies the stored voltage to the amplifier 70, which is made up of a pair of transistors 142 and 144, to provide the development electrode biasing voltage on a conductor 146.
  • the electrode 72 which is the first electrode adjacent to which the copy passes as it moves through the devel oper system, receives the full biasing potential.
  • the second electrode 74 receives the potential at the common terminal of diodes 148 and 150.
  • Electrode 76 receives the potential at the common terminal of diodes 150 and 152, while the last development electrode 78 receives the potential at the common terminal of diode 152 and resistor 154.
  • the power supply 156 which supplies the 600 volt po' tential and the 300 bolt potential to various points in the circuit, may be disconnected from the sensing circuit by any convenient means.
  • a switch 158 in the output line of supply 156 we have indicated a switch 158 in the output line of supply 156.
  • a cam follower 160 is adapted to be operated to close switch 158 to apply power to the sensing circuit.
  • Follower 160 may be operated in any convenient manner.
  • drum 12 rotates in the direction of the arrows shown in FIGS. 1 and 2.
  • Cam 48 actuates follower 50 to apply power from the source 28 to the corona 26 so that the surface of layer 16 receives a uniform charge over the period of time for which the cam 48 actuates the follower 50.
  • cam 54 actuates follower 56 to close switch 36 to connect the control arrangement 34 to the optical system 32 to begin the exposure step.
  • This exposure step lasts for the extent of cam 54 so that, as can be seen from FIG. 1, there is a fully charged but unexposed area following the image area.
  • cam 54 closes switch 158 to apply power to the sensing circuit 68.
  • the electrodes sense the potentials of areas of the image covered thereby.
  • the sensing cuircuit selects the least negative of the potentials which is sampled and held.
  • the resultant signal is amplified and applied to the development electrodes 72, 74, 76 and 78. It will readily be appreciated that this potential will be equal to or somewhat greater than the actual residual potential in background areas of the image so that we ensure that no development of these background areas takes place.
  • a system for automatically controlling the biasing potential on a developer electrode in an electrostatic copying machine including in combination, a support, a surface layer of photoconductive material on said support adapted to receive a latent electrostatic image to be developed, a developer unit for contacting developer fluid with said image to develop the same, a biasing electrode in said developer unit.
  • a sensing electrode insulated from ground, means mounting said sensing electrode in said developer unit at a location at which developer fluid is positioned between and in contact with both said photoconductive surface and said sensing electrode to enable said sensing electrode to assume substantially the potential on said surface by conduction, and means responsive to the potential of said sensing electrode for applying a biasing potential to said biasing electrode.
  • sensing electrode mounting means mounts said sensing electrode at a location at which it registers with a portion of said image in the course of a developing operation.
  • a system as in claim 2 including means mounting said support and said developer unit for relative movement, and in which said sensing electrode mounting means positions said electrode adjacent to the point at which said image enters said developer unit.
  • a system as in claim 4 in which said developer between said surface and said sensing electrode and said photoconductor has a certain high resistance and in which said means responsive to the potential sensed by said sensing electrode includes a measuring circuit having an input resistance which is orders of magnitude greater than said resistance.
  • a system as in claim 1 including means for producing a reverse bias between said surface and said biasing electrode in the course of operation of said machine.
  • said reverse bias producing means comprises means for producing a charged unexposed area on said surface outside the area of said image.
  • a system as in claim 8 including means for moving said support and said developer unit relative to each other and in which said charged unexposed area trails said image area in the direction of said relative movement.
  • sensing electrode is an electrically floating electrode.
  • Apparatus for developing a latent electrostatic image carried by the surface of a photoconductor including in combination, a developer applicator unit for applying developer to said surface, said applicator unit having an entry and an exit, means for moving said surface and said developer applicator unit relative to each other to carry said image through said unit in a direction from said entry toward said exit, a biasing electrode in said developer unit, an electrically floating sensing electrode of conductive material, means mounting said sensing electrode in said developer unit at a location at which developer passes between said sensing electrode and said surface to cause said electrode to sense the potential of said surface by virtue of conduction through said developer, said developer between said sensing electrode and said surface having a certain resistance. and means including a measuring circuit having an input impedance orders of magnitude greater than said resistance and responsive to said potential sensed by said sensing electrode for applying a biasing potential to said biasing electrode.
  • Apparatus as in claim 12 including means for producing a reverse bias between said biasing electrode and said surface following a developing operation.
  • Apparatus as in claim 14 in which said means for producing said reverse bias comprises means for producing a reverse field between the development electrode and an area on said surface outside the area of said image.
  • Apparatus as in claim 15 in which said photoconductor is an organic photoconductor and in which said developer is made up of charged particles suspended in a liquid having a high resistance.
  • said sensing electrode is adjacent to the entry of said developer unit and in which said measuring circuit comprises a storage capacitor, means responsive to movement of an initial portion of an image into said developer unit for enabling bidirectional charging of said capacitor in response to a sensed potential, means responsive to movement of an intermediate portion of said image into said developer unit for enabling only unidirectional charging of said capacitor in response to sensed potential and means responsive to entry of the remainder of said image into said delivery unit for disabling charging of said capacitor.
  • said means including said measuring circuit comprises a source of power for said circuit and means for disconnecting said source from said circuit as non-image areas of said surface pass through said developer unit.
  • Apparatus for developing a latent electrostatic image carried by the surface of a photoconductor including in combination, a developer applicator unit for applying developer to said surface, said applicator unit having an entry and an exit, means for moving said surface and said developer applicator unit relative to each other to carry said image through said unit in a direction from said entry toward said exit, a developer electrode in said unit, a plurality of electrically floating sensing electrodes of conductive material, means mounting said sensing electrodes along a line extending generally across the direction of relative movement of said surface and said unit and at a location at which developer passes between said sensing electrodes and said surface to cause said sensing electrodes to sense the potential of said surface in areas thereof adjacent to said electrodes by virtue of conduction through the developer and means responsive to the potential sensed by said sensing electrodes for applying a potential to said development electrode.
  • said plurality of sensing electrodes includes a central electrode adapted to scan the portion of the image corresponding to the central normally printed area of an original and an edge electrode adapted to scan the portion of the image corresponding to a normally unprinted border area of an original.
  • Apparatus as in claim 19 in which said means responsive to the potential sensed by said sensing electrodes comprises means for selecting the potential of the lowest magnitude sensed by said sensing electrodes.
  • said plurality of sensing electrodes includes a central electrode adapted to scan the portion of the image corresponding to the normally printed area of an original and an edge electrode adapted to scan a portion of the image corresponding to a normally unprinted border area of an original, and in which said means responsive to the potential sensed by said sensing electrode comprises means for selecting the sensed potential of the lowest magnitude.
  • Apparatus as in claim l9 including a plurality of development electrodes spaced in the direction of rela tive movement of said surface and said unit, and means for applying said biasing potential to said development electrodes in decreasing steps from the first development electrode to the last development electrode in said direction of relative movement.
  • Apparatus as in claim 24 in which said means responsive to said potential sensed by said sensing electrodes comprises a storage capacitor, means responsive to movement of an initial portion of an image into said developer unit for enabling bidirectional charging of said capacitor in response to a sensed potential, means responsive to movement of an intermediate portion of said image into said developer unit for enabling only unidirectional charging of said capacitor in response to sensed potential and means responsive to entry of the remainder of said image into said developer unit for disabling charging of said capacitor.
  • Apparatus as in claim 19 in which said means re sponsive to said potential sensed by said sensing electrodes comprises a sensing circuit, a source of power for said sensing circuit and means for disconnecting said source from said circuit as non-image areas of said surface pass through said developer unit.

Landscapes

  • Physics & Mathematics (AREA)
  • General Physics & Mathematics (AREA)
  • Developing For Electrophotography (AREA)
  • Wet Developing In Electrophotography (AREA)
  • Control Or Security For Electrophotography (AREA)
US479659A 1974-06-17 1974-06-17 Automatic development electrode bias control system Expired - Lifetime US3892481A (en)

Priority Applications (9)

Application Number Priority Date Filing Date Title
US479659A US3892481A (en) 1974-06-17 1974-06-17 Automatic development electrode bias control system
CA000222749A CA1149154A (en) 1974-06-17 1975-03-21 Automatic development electrode bias control system
IT21838/75A IT1034714B (it) 1974-06-17 1975-03-28 Sistema per il controllo automatico della polarizzazione di un elettrodo di sviluppo di uno sviluppatore
GB13269/75A GB1483400A (en) 1974-06-17 1975-04-01 Development electrode bias control apparatus
FR7510654A FR2280117A1 (fr) 1974-06-17 1975-04-04 Systeme de reglage automatique de la polarisation de developpement dans une machine a photocopier electrostatique
DE19752516012 DE2516012A1 (de) 1974-06-17 1975-04-12 Vorrichtung zur automatischen kontrolle des vorspannungspotentials einer entwicklerelektrode bei einem elektro- statischen kopiergeraet
JP50044879A JPS6158829B2 (en, 2012) 1974-06-17 1975-04-15
CA000412994A CA1154950A (en) 1974-06-17 1982-10-06 Automatic development electrode bias control system
US06/507,958 USRE31964E (en) 1974-06-17 1983-06-27 Automatic development electrode bias control system

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
US479659A US3892481A (en) 1974-06-17 1974-06-17 Automatic development electrode bias control system

Related Child Applications (1)

Application Number Title Priority Date Filing Date
US06/507,958 Reissue USRE31964E (en) 1974-06-17 1983-06-27 Automatic development electrode bias control system

Publications (1)

Publication Number Publication Date
US3892481A true US3892481A (en) 1975-07-01

Family

ID=23904891

Family Applications (1)

Application Number Title Priority Date Filing Date
US479659A Expired - Lifetime US3892481A (en) 1974-06-17 1974-06-17 Automatic development electrode bias control system

Country Status (7)

Country Link
US (1) US3892481A (en, 2012)
JP (1) JPS6158829B2 (en, 2012)
CA (1) CA1149154A (en, 2012)
DE (1) DE2516012A1 (en, 2012)
FR (1) FR2280117A1 (en, 2012)
GB (1) GB1483400A (en, 2012)
IT (1) IT1034714B (en, 2012)

Cited By (39)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3980049A (en) * 1975-01-28 1976-09-14 Ricoh Co., Ltd. Developing unit for electrophotography
US3981267A (en) * 1975-05-20 1976-09-21 Savin Business Machines Corporation Electrophotographic liquid developing system
FR2326726A1 (fr) * 1975-10-01 1977-04-29 Ricoh Kk Procede de developpement a polarisation automatique dans des machines de reprographie par voie electrophotographique
FR2326727A1 (fr) * 1975-10-01 1977-04-29 Ricoh Kk Procede de developpement pour un appareil de reprographie electrophotographique
US4021111A (en) * 1974-06-10 1977-05-03 Ricoh Co., Ltd. Developing device in electrophotographic copying apparatus
US4025184A (en) * 1974-01-21 1977-05-24 Ricoh Co., Ltd. Developing electrode contamination prevention system for electrophotography
US4044718A (en) * 1976-09-10 1977-08-30 Xonics, Inc. Electrostatic fountain developer
US4045217A (en) * 1974-12-24 1977-08-30 Ricoh Company, Ltd. Developing process for electrophotography
US4050806A (en) * 1974-05-10 1977-09-27 Ricoh Co., Ltd. Method and apparatus for electrically biasing developing electrode of electrophotographic device
US4087171A (en) * 1974-10-21 1978-05-02 Ricoh Co., Ltd. Electrophotographic exposure and development system
US4105324A (en) * 1975-10-14 1978-08-08 Eastman Kodak Company Electrophotographic apparatus having compensation for rest-run performance variations
US4111152A (en) * 1976-05-17 1978-09-05 Ricoh Co., Ltd. Electrostatographic apparatus comprising improved development bias means
US4129375A (en) * 1974-05-10 1978-12-12 Ricoh Company, Ltd. Method and apparatus for electrically biasing developing electrode of electrophotography device
US4136945A (en) * 1975-10-14 1979-01-30 Eastman Kodak Company Electrophotographic apparatus having compensation for changes in sensitometric properties of photoconductors
US4139299A (en) * 1975-04-04 1979-02-13 Ricoh Company, Ltd. Auto-bias developing apparatus
US4141643A (en) * 1974-09-13 1979-02-27 Ricoh Company, Ltd. Developing electrode arrangement for electrophotographic apparatus
DE2909343A1 (de) * 1978-03-09 1979-09-13 Ricoh Kk Elektrostatographische einrichtung
US4176942A (en) * 1976-02-02 1979-12-04 Ricoh Company, Ltd. Electrophotographic copying apparatus
US4183655A (en) * 1975-10-07 1980-01-15 Ricoh Company, Ltd. Cleaning means for image transfer unit in electrophotographic copying machines
US4244321A (en) * 1978-02-14 1981-01-13 James River Graphics, Inc. Electrographic development electrode
USRE30477E (en) * 1979-05-10 1981-01-13 Savin Corporation Electrophotographic liquid developing system
US4247195A (en) * 1978-06-21 1981-01-27 Ricoh Co., Ltd. Bias device for a copying machine
US4326796A (en) * 1979-12-13 1982-04-27 International Business Machines Corporation Apparatus and method for measuring and maintaining copy quality in an electrophotographic copier
US4373800A (en) * 1979-12-03 1983-02-15 Ricoh Company, Ltd. Wet type electrophotographic copying machine
US4423134A (en) * 1974-11-12 1983-12-27 Ricoh Company, Ltd. Developing unit for electrophotography
DE3637101A1 (de) * 1985-11-04 1987-05-07 Savin Corp Vorrichtung mit einem fotoleiter, insbesondere kopiergeraet
US4669859A (en) * 1982-03-23 1987-06-02 Ricoh Company, Ltd. Developing device
EP0240042A1 (en) * 1986-02-25 1987-10-07 Coulter Stork Patents B.V. Method and device for the development of a latent electrostatic image
US4761671A (en) * 1987-02-02 1988-08-02 Eastman Kodak Company Electrophotographic subprocess for apparatus using discharged area toning
US4843425A (en) * 1986-09-12 1989-06-27 Konishiroku Photo Industry Co., Ltd. Image forming method and apparatus
US4957213A (en) * 1990-03-05 1990-09-18 White Dennis H Card file stop
US4984019A (en) * 1990-02-26 1991-01-08 Xerox Corporation Electrode wire cleaning
US5027744A (en) * 1988-12-05 1991-07-02 Brother Kogyo Kabushiki Kaisha Developing device with development electrode cleaning unit
US5164771A (en) * 1978-08-24 1992-11-17 Canon Kabushiki Kaisha Image forming apparatus which adjusts illumination levels independently for test samples and for originals
US5243391A (en) * 1992-05-01 1993-09-07 Printware, Inc. Varying an electric field, during development of a latent electrostatic image with developer solution, in proportion to a sensed concentration of toner that is within the developer solution
US5398105A (en) * 1990-06-06 1995-03-14 Mitsubishi Paper Mills Limited Method of electrophotographic wet reversal development
US5404213A (en) * 1991-03-04 1995-04-04 Kabushiki Kaisha Toshiba Electrophotographic printing apparatus capable of printing images by electrophotographic processing and its start-up method
US5640230A (en) * 1995-02-01 1997-06-17 Victor Company Of Japan, Ltd. Electrostatic latent image developing methods and apparatuses for use with the methods
US5748217A (en) * 1995-11-16 1998-05-05 Phoenix Precision Graphics, Inc. Charge compensation circuit for an electrostatic writing head

Families Citing this family (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
DE2655158C2 (de) * 1976-12-06 1986-04-03 Hoechst Ag, 6230 Frankfurt Verfahren und Vorrichtung zum Entwickeln eines elektrostatischen latenten Ladungsbildes

Citations (7)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2956487A (en) * 1955-03-23 1960-10-18 Rca Corp Electrostatic printing
US3611982A (en) * 1969-08-29 1971-10-12 Xerox Corp Development electrode control apparatus
US3654893A (en) * 1970-05-01 1972-04-11 Eastman Kodak Co Automatic bias control for electrostatic development
US3782818A (en) * 1972-11-17 1974-01-01 Savin Business Machines Corp System for reducing background developer deposition in an electrostatic copier
US3788739A (en) * 1972-06-21 1974-01-29 Xerox Corp Image compensation method and apparatus for electrophotographic devices
US3815988A (en) * 1973-05-17 1974-06-11 Xerox Corp Image density control apparatus
US3835380A (en) * 1973-08-14 1974-09-10 Xerox Corp Electrometer system

Family Cites Families (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPS497014A (en, 2012) * 1972-05-08 1974-01-22

Patent Citations (7)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2956487A (en) * 1955-03-23 1960-10-18 Rca Corp Electrostatic printing
US3611982A (en) * 1969-08-29 1971-10-12 Xerox Corp Development electrode control apparatus
US3654893A (en) * 1970-05-01 1972-04-11 Eastman Kodak Co Automatic bias control for electrostatic development
US3788739A (en) * 1972-06-21 1974-01-29 Xerox Corp Image compensation method and apparatus for electrophotographic devices
US3782818A (en) * 1972-11-17 1974-01-01 Savin Business Machines Corp System for reducing background developer deposition in an electrostatic copier
US3815988A (en) * 1973-05-17 1974-06-11 Xerox Corp Image density control apparatus
US3835380A (en) * 1973-08-14 1974-09-10 Xerox Corp Electrometer system

Cited By (44)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US4025184A (en) * 1974-01-21 1977-05-24 Ricoh Co., Ltd. Developing electrode contamination prevention system for electrophotography
US4129375A (en) * 1974-05-10 1978-12-12 Ricoh Company, Ltd. Method and apparatus for electrically biasing developing electrode of electrophotography device
USRE31707E (en) * 1974-05-10 1984-10-16 Ricoh Company, Ltd. Method and apparatus for electrically biasing developing electrode of electrophotographic device
US4050806A (en) * 1974-05-10 1977-09-27 Ricoh Co., Ltd. Method and apparatus for electrically biasing developing electrode of electrophotographic device
US4021111A (en) * 1974-06-10 1977-05-03 Ricoh Co., Ltd. Developing device in electrophotographic copying apparatus
USRE30535E (en) * 1974-06-10 1981-03-03 Ricoh Co., Ltd. Developing device in electrophotographic copying apparatus
US4141643A (en) * 1974-09-13 1979-02-27 Ricoh Company, Ltd. Developing electrode arrangement for electrophotographic apparatus
US4087171A (en) * 1974-10-21 1978-05-02 Ricoh Co., Ltd. Electrophotographic exposure and development system
US4423134A (en) * 1974-11-12 1983-12-27 Ricoh Company, Ltd. Developing unit for electrophotography
US4045217A (en) * 1974-12-24 1977-08-30 Ricoh Company, Ltd. Developing process for electrophotography
US3980049A (en) * 1975-01-28 1976-09-14 Ricoh Co., Ltd. Developing unit for electrophotography
US4139299A (en) * 1975-04-04 1979-02-13 Ricoh Company, Ltd. Auto-bias developing apparatus
US3981267A (en) * 1975-05-20 1976-09-21 Savin Business Machines Corporation Electrophotographic liquid developing system
FR2326726A1 (fr) * 1975-10-01 1977-04-29 Ricoh Kk Procede de developpement a polarisation automatique dans des machines de reprographie par voie electrophotographique
US4168329A (en) * 1975-10-01 1979-09-18 Ricoh Co., Ltd. Auto-bias developing process and an electrophotographic copying machine
FR2326727A1 (fr) * 1975-10-01 1977-04-29 Ricoh Kk Procede de developpement pour un appareil de reprographie electrophotographique
US4183655A (en) * 1975-10-07 1980-01-15 Ricoh Company, Ltd. Cleaning means for image transfer unit in electrophotographic copying machines
US4105324A (en) * 1975-10-14 1978-08-08 Eastman Kodak Company Electrophotographic apparatus having compensation for rest-run performance variations
US4136945A (en) * 1975-10-14 1979-01-30 Eastman Kodak Company Electrophotographic apparatus having compensation for changes in sensitometric properties of photoconductors
US4176942A (en) * 1976-02-02 1979-12-04 Ricoh Company, Ltd. Electrophotographic copying apparatus
US4111152A (en) * 1976-05-17 1978-09-05 Ricoh Co., Ltd. Electrostatographic apparatus comprising improved development bias means
US4044718A (en) * 1976-09-10 1977-08-30 Xonics, Inc. Electrostatic fountain developer
US4244321A (en) * 1978-02-14 1981-01-13 James River Graphics, Inc. Electrographic development electrode
DE2909343A1 (de) * 1978-03-09 1979-09-13 Ricoh Kk Elektrostatographische einrichtung
US4247195A (en) * 1978-06-21 1981-01-27 Ricoh Co., Ltd. Bias device for a copying machine
US5164771A (en) * 1978-08-24 1992-11-17 Canon Kabushiki Kaisha Image forming apparatus which adjusts illumination levels independently for test samples and for originals
USRE30477E (en) * 1979-05-10 1981-01-13 Savin Corporation Electrophotographic liquid developing system
US4373800A (en) * 1979-12-03 1983-02-15 Ricoh Company, Ltd. Wet type electrophotographic copying machine
US4326796A (en) * 1979-12-13 1982-04-27 International Business Machines Corporation Apparatus and method for measuring and maintaining copy quality in an electrophotographic copier
US4669859A (en) * 1982-03-23 1987-06-02 Ricoh Company, Ltd. Developing device
DE3637101A1 (de) * 1985-11-04 1987-05-07 Savin Corp Vorrichtung mit einem fotoleiter, insbesondere kopiergeraet
FR2589594A1 (fr) * 1985-11-04 1987-05-07 Savin Corp Appareil de commande de charge et de polarisation pour copieur electrophotographique
US4678317A (en) * 1985-11-04 1987-07-07 Savin Corporation Charge and bias control system for electrophotographic copier
EP0240042A1 (en) * 1986-02-25 1987-10-07 Coulter Stork Patents B.V. Method and device for the development of a latent electrostatic image
US4843425A (en) * 1986-09-12 1989-06-27 Konishiroku Photo Industry Co., Ltd. Image forming method and apparatus
US4761671A (en) * 1987-02-02 1988-08-02 Eastman Kodak Company Electrophotographic subprocess for apparatus using discharged area toning
US5027744A (en) * 1988-12-05 1991-07-02 Brother Kogyo Kabushiki Kaisha Developing device with development electrode cleaning unit
US4984019A (en) * 1990-02-26 1991-01-08 Xerox Corporation Electrode wire cleaning
US4957213A (en) * 1990-03-05 1990-09-18 White Dennis H Card file stop
US5398105A (en) * 1990-06-06 1995-03-14 Mitsubishi Paper Mills Limited Method of electrophotographic wet reversal development
US5404213A (en) * 1991-03-04 1995-04-04 Kabushiki Kaisha Toshiba Electrophotographic printing apparatus capable of printing images by electrophotographic processing and its start-up method
US5243391A (en) * 1992-05-01 1993-09-07 Printware, Inc. Varying an electric field, during development of a latent electrostatic image with developer solution, in proportion to a sensed concentration of toner that is within the developer solution
US5640230A (en) * 1995-02-01 1997-06-17 Victor Company Of Japan, Ltd. Electrostatic latent image developing methods and apparatuses for use with the methods
US5748217A (en) * 1995-11-16 1998-05-05 Phoenix Precision Graphics, Inc. Charge compensation circuit for an electrostatic writing head

Also Published As

Publication number Publication date
JPS6158829B2 (en, 2012) 1986-12-13
GB1483400A (en) 1977-08-17
DE2516012A1 (de) 1976-01-02
CA1149154A (en) 1983-07-05
DE2516012C2 (en, 2012) 1987-08-13
IT1034714B (it) 1979-10-10
FR2280117B1 (en, 2012) 1977-04-15
JPS511144A (en, 2012) 1976-01-07
FR2280117A1 (fr) 1976-02-20

Similar Documents

Publication Publication Date Title
US3892481A (en) Automatic development electrode bias control system
CA1150946A (en) Method and apparatus for electrically biasing developing electrode of electrophotographic device
US3944354A (en) Voltage measurement apparatus
US3782818A (en) System for reducing background developer deposition in an electrostatic copier
US3663219A (en) Electrophotographic process
US3981267A (en) Electrophotographic liquid developing system
US3551146A (en) Induction imaging system
US2996400A (en) Positive and negative electroprinting
GB1445671A (en) Transferring charged particles
US3599605A (en) Self-biasing development electrode for electrophotography
US4678317A (en) Charge and bias control system for electrophotographic copier
JPH01173764U (en, 2012)
US4395112A (en) Latent electrostatic image developing device
US3990394A (en) Control circuit used in development of electrostatic latent images and developing apparatus
US4346986A (en) Image formation method and apparatus
CA1070572A (en) Prevention of toner deposition at end of copying in an auto bias developing process and apparatus
GB1586088A (en) Dc electrometer
US4607937A (en) Electrostatic recording apparatus
US4620203A (en) Electrostatic image forming apparatus using field effect transistors
US3834809A (en) Electrophotographic system
USRE31964E (en) Automatic development electrode bias control system
US4291643A (en) Developing apparatus in a magnification-variable copier
USRE30477E (en) Electrophotographic liquid developing system
US4757343A (en) Electrostatic image output apparatus
US3058444A (en) Apparatus for developing electrostatic image on electrographic sheet

Legal Events

Date Code Title Description
AS Assignment

Owner name: FOOTHILL CAPITAL CORPORATION, A CA. CORP., CALIFOR

Free format text: ASSIGNMENT OF ASSIGNORS INTEREST.;ASSIGNOR:SAVIN CORPORATION;REEL/FRAME:004831/0089

Effective date: 19880113

AS Assignment

Owner name: SAVIN CORPORATION, CONNECTICUT

Free format text: ASSIGNMENT OF ASSIGNORS INTEREST;ASSIGNOR:FOOTHILL CAPITAL CORPORATION;REEL/FRAME:008113/0213

Effective date: 19951218