US3911865A - Toner pickoff apparatus - Google Patents

Toner pickoff apparatus Download PDF

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Publication number
US3911865A
US3911865A US346485A US34648573A US3911865A US 3911865 A US3911865 A US 3911865A US 346485 A US346485 A US 346485A US 34648573 A US34648573 A US 34648573A US 3911865 A US3911865 A US 3911865A
Authority
US
United States
Prior art keywords
developer
roller
toner particles
field
latent image
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
US346485A
Other languages
English (en)
Inventor
Stewart William Volkers
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
Priority to US346485A priority Critical patent/US3911865A/en
Priority to CA190,056A priority patent/CA1029942A/fr
Priority to DE19742401932 priority patent/DE2401932A1/de
Priority to GB199974A priority patent/GB1430876A/en
Priority to NL7400678A priority patent/NL7400678A/xx
Priority to FR7401658A priority patent/FR2214144B1/fr
Priority to JP49035088A priority patent/JPS502941A/ja
Application granted granted Critical
Publication of US3911865A publication Critical patent/US3911865A/en
Anticipated expiration legal-status Critical
Expired - Lifetime legal-status Critical Current

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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
    • G03G15/08—Apparatus for electrographic processes using a charge pattern for developing using a solid developer, e.g. powder developer
    • G03G15/0801—Apparatus for electrographic processes using a charge pattern for developing using a solid developer, e.g. powder developer for cascading
    • 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
    • G03G15/08—Apparatus for electrographic processes using a charge pattern for developing using a solid developer, e.g. powder developer
    • G03G15/0822—Arrangements for preparing, mixing, supplying or dispensing developer
    • G03G15/0887—Arrangements for conveying and conditioning developer in the developing unit, e.g. agitating, removing impurities or humidity
    • 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
    • G03G15/08—Apparatus for electrographic processes using a charge pattern for developing using a solid developer, e.g. powder developer
    • G03G15/0822—Arrangements for preparing, mixing, supplying or dispensing developer
    • G03G15/0887—Arrangements for conveying and conditioning developer in the developing unit, e.g. agitating, removing impurities or humidity
    • G03G15/0891—Arrangements for conveying and conditioning developer in the developing unit, e.g. agitating, removing impurities or humidity for conveying or circulating developer, e.g. augers

Definitions

  • toner that is charged to the wrong 12 Claims, 2 Drawing Figures polarity may be removed from the developer mix by a biased roller prior to developing the electrostatic latent image.
  • the removal of the toner particles from the developer prior to presenting the developer to an 1 37 electrostatic latent image substantially reduces background when developing the latent image.
  • the background development level is a function of the concentration of improperly charged toner particles in the developer with background becoming worse with an increase in this type of toner. The reasons are not fully understood, but some general observations may be made.
  • the electrostatic latent image When positive-to-positive reproduction is desired, and the electrostatic latent image carries a positive charge, then the carrier will have a positive charge and the toner a negative charge.
  • the electrostatic latent image may have a charge of +800 volts and the background will have a charge of around +200 volts and the toner will carry negative charge.
  • lt is a further object of this invention to eliminate the above disadvantages and thereby suppress background by withdrawing toner particles, which are charged to the wrong polarity, from the developer prior to presenting the developer to an electrostatic latent image.
  • a still further object of this invention is to suppress development of selected lower contrast electrostatic images by removing lower charged toner particles from the developer prior to presenting the developer to an electrostatic image.
  • FIG. 1 is a view of the development system utilizing the principles of this invention.
  • FIG. 2 is a view of a magnetic brush development system utilizing the principles of this invention.
  • a drum 10 has a photosensitive surface 12 thereon bearing an electrostatic latent image.
  • the drum 10 is rotated in a clockwise direction by a motor 14 outlined in block form.
  • a developer housing 16 is located adjacent the drum and contains a toner reservoir 18 having a supply of toner 20 therein and a developer sump having a supply of developer 22 therein.
  • the developer comprises carrier and toner particles so selected that a triboelectric attraction exists between them causing the two particles to cling together and acquire an opposite charge.
  • a bucket conveyor 24 is rotatably mounted in the housing 16 and is arranged to convey developer 22 from the developer sump upwards and deposit the same onto a chute 26.
  • a motor 28 shown in block diagram, is positively connected to a pulley 30 to rotate the pulley and thereby the bucket conveyor 24.
  • a toner pickoff rotatable biased roller 32 is located at the bottom of the chute 26 and has a motor 34 (shown in block diagram) positively connected thereto for rotating the same in a clockwise direction.
  • the roller 32 collects toner particles thereon in a manner to be described hereafter.
  • a biased development electrode 33 is provided adjacent the roller 32 to develop toner particles onto the roller 32.
  • a combined scraper and guide member 36 is located in the housing and is tangentially disposed relative to the surface of the roller 32 to engage and scrape off any toner particles collected on the roller 32 and guide the same back into the developer sump without engaging the photosensitive surface.
  • the roller 32 has a positive voltage V applied thereto and the development electrode 33 has either a negative or less positive voltage V applied thereto.
  • the difference in the voltage potentials V, and V is usually such as to produce an attractive field which is equal to or slightly greater than the attractive field in the background areas of the latent image.
  • the roller 32 has a negative voltage V, applied thereto and the development electrode 33 has either a positive or less negative voltage V applied thereto.
  • the difference in the voltage potentials V and V is usually such as to produce a field which will attract the positive charge particles to the roller 32 as the roller 32 rotates.
  • the negative charged particles will not develop on the roll 32 since the roll 32 is at the lower potential compared to the electrode 33. Any negative toner which is attracted to the electrode 33 will be physically removed by and/or attracted to the passing developer.
  • the scraper 36 engages the roller 32 to remove any toner particles deposited thereon.
  • the toner particles fall by gravity over the scraper guide 36 back into the developer sump without engaging the photosensitive surface 12 wherein the toner particles will be mixed with the carrier particles to become triboelectrically correctly charged and redistributed by the bucket conveyor over the chute 26 and past the roller 32 and onto the photosensitive surface to develop the latent image thereon.
  • connection between the motors and their associated members to be driven thereby have been omitted for clarity and it should be understood that such connections can be any type wellknown in the art.
  • the latent image is imposed on the photosensitive surface 12 and the developed latent image is transferred from the photosensitive surface to a copy paper by wellknown xerographic techniques as for instance described in US. Pat. No. 3,336,905.
  • a developer mix 100 comprises ferromagnetic carrier particles and toner particles located in a developer sump.
  • a magnetic roller 102 is rotatably mounted in the sump and has a portion thereof disposed within the developer mix 100 to attract developer thereto to present the same to the latent image on the photosensitive surface 12a.
  • a motor (shown in block form) 104 is utilized to rotate the magnetic roller 102.
  • the toner pickoff roller 32a is located adjacent the magnetic roll 102.
  • the roller 32a has a voltage potential V applied thereto and the magnetic brush 102 has a voltage potential V applied thereto.
  • the potential V may be more positive or more negative than the potential on roller 32a depending upon whether it is desired to develop on the roller 32a the weakly charged particles or the particles charged to the wrong polarity, respectively. This is assuming a positively charged image.
  • the roll 32a will attract those particles which are charged either in the wrong polarity or the weakly charged particles depending upon the field produced by the potentials V and V
  • the particles attracted by the roller 32a are scraped off the roller by the scraper and guide 36a and are returned back to the developer sump for re-charging and re-use.
  • an electrostatic processor having a photosensitive surface for carrying an electrostatic latent image, and a development system including means for transporting developer along a predetermined path leading toward and away from said surface to develop said image; said developer containing properly and improperly charged toner particles, with the properly charged particles being triboelectrically attracted to carrier particles; the improvement comprising the combination of electrically conductive means adjacent said path and upstream of said surface, and means for biasing said conductive means to create an electric field which selectively attracts at least some of the improperly charged toner particles toward said conductive means while repelling the properly charged toner particles therefrom, whereby improperly charged toner particles are removed from said developer prior to developing said image to thereby suppress background development.
  • said means for transporting said developer to said photosensitive surface comprises a chute located above the photosensitive surface and means for cascading said developer onto said chute and across said photosensitive surface, said conductive means being located within the path of the cascading developer.
  • said means for transporting said developer to said electrostatic latent image comprises a magnetic roller, said conductive means including said magnetic roller and another member adjacent said magnetic roller, with said field being established between said member and said magnetic roller.
  • said conductive means includes a roller on one side of said path and an electrode adjacent said roller on the opposite side of said path, and said biasing means biases said roller and said electrode to establish said field therebetween.
  • a development system for developing said latent image through the use of a developer comprising toner particles triboelectrically attracted to carrier particles; the combination of means for presenting said developer to said surface to develop said electrostatic latent image, and means for subjecting said developer to an electrical field prior to developing said image, said field being selected to remove from said developer relatively weakly charged toner particles having a polarity opposite the image polarity, thereby reducing the quantity of toner particles which tend to be attracted to background areas of said image by residual electrostatic charge onsaid surface.

Landscapes

  • Physics & Mathematics (AREA)
  • General Physics & Mathematics (AREA)
  • Magnetic Brush Developing In Electrophotography (AREA)
  • Dry Development In Electrophotography (AREA)
US346485A 1973-01-17 1973-03-30 Toner pickoff apparatus Expired - Lifetime US3911865A (en)

Priority Applications (7)

Application Number Priority Date Filing Date Title
US346485A US3911865A (en) 1973-03-30 1973-03-30 Toner pickoff apparatus
CA190,056A CA1029942A (fr) 1973-03-30 1974-01-14 Appareil d'enlevement de toner
DE19742401932 DE2401932A1 (de) 1973-01-17 1974-01-16 Entwicklungssystem in einer elektrostatischen kopiermaschine
GB199974A GB1430876A (en) 1973-01-17 1974-01-16 Apparatus for developing an electrostatic latent image
NL7400678A NL7400678A (fr) 1973-01-17 1974-01-17
FR7401658A FR2214144B1 (fr) 1973-01-17 1974-01-17
JP49035088A JPS502941A (fr) 1973-03-30 1974-03-28

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
US346485A US3911865A (en) 1973-03-30 1973-03-30 Toner pickoff apparatus

Publications (1)

Publication Number Publication Date
US3911865A true US3911865A (en) 1975-10-14

Family

ID=23359610

Family Applications (1)

Application Number Title Priority Date Filing Date
US346485A Expired - Lifetime US3911865A (en) 1973-01-17 1973-03-30 Toner pickoff apparatus

Country Status (3)

Country Link
US (1) US3911865A (fr)
JP (1) JPS502941A (fr)
CA (1) CA1029942A (fr)

Cited By (7)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US4178095A (en) * 1978-04-10 1979-12-11 International Business Machines Corporation Abnormally low reflectance photoconductor sensing system
US4179213A (en) * 1978-04-10 1979-12-18 International Business Machines Corporation Vector pinning in an electrophotographic machine
US4183657A (en) * 1978-04-10 1980-01-15 International Business Machines Corporation Dynamic reference for an image quality control system
US4351604A (en) * 1979-04-26 1982-09-28 Ricoh Company, Ltd. Multi-color electrostatic copying apparatus
EP0266961A2 (fr) * 1986-11-03 1988-05-11 Xerox Corporation Appareil d'impression électrostatique direct et ensemble de distribution de toner-développateur pour cet appareil
EP0497601A2 (fr) * 1991-01-31 1992-08-05 Canon Kabushiki Kaisha Appareil de développement et élément de transport de développeur pour cet appareil
US20080138116A1 (en) * 2006-12-06 2008-06-12 Xerox Corporation Developer purification station or structure

Families Citing this family (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPS5416828A (en) * 1977-07-08 1979-02-07 Fuji Electric Co Ltd Method and device for breaking reinforced concrete by induction heating
JPS5633831Y2 (fr) * 1978-04-27 1981-08-10
JPS54149643A (en) * 1978-05-17 1979-11-24 Ricoh Co Ltd Developing agent recovering device for zerographic apparatus

Citations (8)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3453045A (en) * 1967-03-23 1969-07-01 Xerox Corp Xerographic development apparatus
US3455276A (en) * 1967-05-23 1969-07-15 Minnesota Mining & Mfg Magnetically responsive powder applicator
US3580673A (en) * 1968-08-26 1971-05-25 Xerox Corp Cleaning apparatus
US3645618A (en) * 1970-12-18 1972-02-29 Xerox Corp Vacuum nozzle to remove agglomerates on a toner applicator
US3662711A (en) * 1970-03-19 1972-05-16 Xerox Corp Development apparatus
US3754962A (en) * 1970-12-21 1973-08-28 Ibm Development of electrostatic images
US3783826A (en) * 1971-08-20 1974-01-08 Xerox Corp Ion film regulating device
US3818864A (en) * 1971-09-14 1974-06-25 Xerox Corp Image developing apparatus

Family Cites Families (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPS498214A (fr) * 1972-05-11 1974-01-24
US3865080A (en) * 1973-01-17 1975-02-11 Xerox Corp Toner pickoff apparatus
JPS5028023A (fr) * 1973-07-17 1975-03-22

Patent Citations (8)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3453045A (en) * 1967-03-23 1969-07-01 Xerox Corp Xerographic development apparatus
US3455276A (en) * 1967-05-23 1969-07-15 Minnesota Mining & Mfg Magnetically responsive powder applicator
US3580673A (en) * 1968-08-26 1971-05-25 Xerox Corp Cleaning apparatus
US3662711A (en) * 1970-03-19 1972-05-16 Xerox Corp Development apparatus
US3645618A (en) * 1970-12-18 1972-02-29 Xerox Corp Vacuum nozzle to remove agglomerates on a toner applicator
US3754962A (en) * 1970-12-21 1973-08-28 Ibm Development of electrostatic images
US3783826A (en) * 1971-08-20 1974-01-08 Xerox Corp Ion film regulating device
US3818864A (en) * 1971-09-14 1974-06-25 Xerox Corp Image developing apparatus

Cited By (10)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US4178095A (en) * 1978-04-10 1979-12-11 International Business Machines Corporation Abnormally low reflectance photoconductor sensing system
US4179213A (en) * 1978-04-10 1979-12-18 International Business Machines Corporation Vector pinning in an electrophotographic machine
US4183657A (en) * 1978-04-10 1980-01-15 International Business Machines Corporation Dynamic reference for an image quality control system
US4351604A (en) * 1979-04-26 1982-09-28 Ricoh Company, Ltd. Multi-color electrostatic copying apparatus
EP0266961A2 (fr) * 1986-11-03 1988-05-11 Xerox Corporation Appareil d'impression électrostatique direct et ensemble de distribution de toner-développateur pour cet appareil
EP0266961A3 (en) * 1986-11-03 1990-01-17 Xerox Corporation Direct electrostatic printing apparatus and toner/developer delivery system therefor
EP0497601A2 (fr) * 1991-01-31 1992-08-05 Canon Kabushiki Kaisha Appareil de développement et élément de transport de développeur pour cet appareil
EP0497601A3 (en) * 1991-01-31 1993-03-31 Canon Kabushiki Kaisha Developing apparatus and developer carrying member therefor
US20080138116A1 (en) * 2006-12-06 2008-06-12 Xerox Corporation Developer purification station or structure
US7672620B2 (en) * 2006-12-06 2010-03-02 Xerox Corporation Developer purification station or structure

Also Published As

Publication number Publication date
CA1029942A (fr) 1978-04-25
JPS502941A (fr) 1975-01-13

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