US3865080A - Toner pickoff apparatus - Google Patents

Toner pickoff apparatus Download PDF

Info

Publication number
US3865080A
US3865080A US324466A US32446673A US3865080A US 3865080 A US3865080 A US 3865080A US 324466 A US324466 A US 324466A US 32446673 A US32446673 A US 32446673A US 3865080 A US3865080 A US 3865080A
Authority
US
United States
Prior art keywords
developer
toner particles
recited
photosensitive surface
charged
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
US324466A
Other languages
English (en)
Inventor
Frederick W Hudson
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 US324466A priority Critical patent/US3865080A/en
Priority to DE19742401932 priority patent/DE2401932A1/de
Priority to GB199974A priority patent/GB1430876A/en
Priority to CA190,249A priority patent/CA1029943A/fr
Priority to NL7400678A priority patent/NL7400678A/xx
Priority to JP49008214A priority patent/JPS49106337A/ja
Priority to FR7401658A priority patent/FR2214144B1/fr
Application granted granted Critical
Publication of US3865080A publication Critical patent/US3865080A/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
    • G03G15/06—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

  • the toner particles are triboelectrically charged through a mixing and tumbling action with the carrier particles present in the developer mix. Normally, however there are some toner particles which carry a low charge and some toner particles which are charged to the wrong polarity. It has been found that 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. 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. Normally, 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 a negative charge.
  • a still further object of this invention is to suppress development of selected lower contrast electrostatic images by removing lower charged toner prior to being presented to an electrostatic image.
  • FIG. 1 is a view of a development system utilizing the 7 principles of this invention
  • FIG. 2 is an enlarged view of the details of a toner collection mechanism utilized in the embodiment of FIG. 1;
  • FIG. 3 is a schematic view of the toner collection mechanism illustrated in FIG. 2;
  • FIG. 4 is a view of a magnetic brush development system utilizing the principles of this invention.
  • FIG. 5 is a view of a modification of the embodiment of FIG. 1.
  • 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.
  • a toner pickoff rotatable 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 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 comprises a plurality of conductive sections or segments 38 each of which alternate with a corresponding one of a plurality of conductive sections or segments 40.
  • the sections 38 are electrically insulated from sections 40 by isulating members 42.
  • Sections 38 are electrically connected by wires .43 to a common lead 44 which is electrically connected to a well-known slip ring assembly (illustrated in block form) which in turn is electrically connected by lead 46 to a positive terminal of a variable power source 50.
  • the sections 40 are electrically connected by wires 45 to a common lead 47 which is electrically connected to the slip ring assembly which is electrically connected by lead 48 to a negative terminal of the power source.
  • the power source 50 may be selectively varied by an operator for selectively varying the potential difference between the sections 38 and 40.
  • the toner will be stripped from its carrier and if the toner is negatively charged, it will be deposited upon the section 38.
  • connections 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 well-known 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 U.S. Pat. No. 3,336,905.
  • a developer mix W 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 R00 to attract developer thereto to present the same to the latent image on the photosensitive surface 12a.
  • a motor (shown in block form) 104i is utilized to rotate the magnetic roller 102.
  • the toner pickoff roller 32a is located adjacent the magnetic roll 102.
  • the roll 32a will attract those particles which are charged in the wrong polarity and the weakly charged particles.
  • 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.
  • the power source 50 can be varied by the operator to change the potential between the segments 33 and 40 in accordance with desired results. For instance, if an original contains high background, development of the background can be suppressed by increasing the potential between the segments 38 and 410 to pick off higher charged toner. Also, the original may contain unwanted pencil marks or other images thereon which are of a lesser density than the main image. The development of the unwanted image may be suppressed by varying the power source 50 to increase the potential between the segments 3% and 40 to pick off higher charged toner which would otherwise develop the unwanted image. This will also reduce somewhat the development density of the resulting image.
  • the roller 32b is located adjacent the photosensitive surface 12b and acts not only as a toner pick-off device but also as a development electrode.
  • the roller 32b acts as a development electrode as long as there is a substantial difference in rotational speed between the surface 12b and the roller 32b whereby the development field will be the difference between the latent image charge on the photosensitive surface and the average potential on the roller 32b.
  • the weakly charged toner and the toner particles charged to the wrong polarity particles will be withdrawn from the developer mix as the mix is being presented to the latent image.
  • a normally biased roller could be substituted for the roller 32 which has been designed especially for attracting not only the weakly charged particles but also the particles which are charged to the wrong polarity.
  • a development electrode could be placed opposite the biased roller when the roller is located as shown in FIG. 1.
  • the potential between the sections 38 and 40 and the relative geometry thereof could be set to achieve withdrawal of either the weakly charged toner or the toner particles charged to the wrong polarity.
  • sections 38 and 40 may also take the form of annular parallel rings the planes of which will be transverse to or angled with respect to the axes of the roller.
  • Another method for collecting both the weakly charged toner particles and the toner particles charged to the wrong polarity is to substitute two oppositely rotating rollers (in the form of a nip) for the roller 32 and pass the developer therebetween.
  • the potential between the rollers will be such that one of the rollers will collect the weakly charged toner particles thereon and the other roller will collect the toner particles thereon which are charged to the wrong polarity.
  • a development system for developing said latent image through the use of a developer having toner particles triboelectrically attracted to carrier particles; said development system comprising the combination of means for transporting said developer along a path leading to said photosensitive surface and means along said path and upstream of said photosensitive surface for electrostatically withdrawing from said developer improperly charged toner particles which would otherwise tend to be attracted to background areas of said image; said withdrawing means including segmented member having at least one pair of conductive segments electrically insulated from each other, and means for providing an electrical potential between said segments, thereby establishing a field for selectively attracting improperly charged toner particles from said developer.
  • said means for transporting said developer to said photosensitive surface comprises a chute located above the pho' tosensitive surface and means for cascading said developer onto said chute, and said means for withdrawing toner particles from said developer is located above said photosensitive surface within the path of the gatording developer.
  • said means for transporting said developer comprises a chute located above the photosensitive surface and means for cascading said developer onto said chute and said photosensitive surface, and said means for withdrawing toner particles from said developer is located within the path of the cascading developer.

Landscapes

  • Physics & Mathematics (AREA)
  • General Physics & Mathematics (AREA)
  • Magnetic Brush Developing In Electrophotography (AREA)
  • Dry Development In Electrophotography (AREA)
US324466A 1973-01-17 1973-01-17 Toner pickoff apparatus Expired - Lifetime US3865080A (en)

Priority Applications (7)

Application Number Priority Date Filing Date Title
US324466A US3865080A (en) 1973-01-17 1973-01-17 Toner pickoff apparatus
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
CA190,249A CA1029943A (fr) 1973-01-17 1974-01-16 Appareil d'enlevement de toner
NL7400678A NL7400678A (fr) 1973-01-17 1974-01-17
JP49008214A JPS49106337A (fr) 1973-01-17 1974-01-17
FR7401658A FR2214144B1 (fr) 1973-01-17 1974-01-17

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
US324466A US3865080A (en) 1973-01-17 1973-01-17 Toner pickoff apparatus

Publications (1)

Publication Number Publication Date
US3865080A true US3865080A (en) 1975-02-11

Family

ID=23263716

Family Applications (1)

Application Number Title Priority Date Filing Date
US324466A Expired - Lifetime US3865080A (en) 1973-01-17 1973-01-17 Toner pickoff apparatus

Country Status (3)

Country Link
US (1) US3865080A (fr)
JP (1) JPS49106337A (fr)
CA (1) CA1029943A (fr)

Cited By (11)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3988816A (en) * 1974-10-23 1976-11-02 Tdk Electronics Company, Limited Magnet roller for electrostatic record developing device
US3996892A (en) * 1975-02-24 1976-12-14 Xerox Corporation Spatially programmable electrode-type roll for electrostatographic processors and the like
US4041903A (en) * 1974-05-21 1977-08-16 Konishiroku Photo Industry Co., Ltd. Developing device for use in electrophotography
US4110034A (en) * 1976-06-24 1978-08-29 Ricoh Company, Ltd. Drum cleaning apparatus for electrostatic copying machine
DE3014372A1 (de) * 1979-04-18 1980-10-23 Tokyo Shibaura Electric Co Entwicklersystem fuer elektrostatisches kopiergeraet
US4318606A (en) * 1980-01-21 1982-03-09 Burroughs Corporation Magnetic toner imaging-multiplexing apparatus
US5115276A (en) * 1991-09-05 1992-05-19 Eastman Kodak Company Magnetic brush development apparatus
US5134442A (en) * 1990-07-26 1992-07-28 Xerox Corporation Electrode wire contamination prevention and detection
US5239344A (en) * 1991-01-16 1993-08-24 Ricoh Company, Ltd. Developing roller having insulating and conductive areas
US6006048A (en) * 1998-10-02 1999-12-21 Xerox Corporation Wrong-sign toner detection system
US20080138116A1 (en) * 2006-12-06 2008-06-12 Xerox Corporation Developer purification station or structure

Families Citing this family (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3911865A (en) * 1973-03-30 1975-10-14 Xerox Corp Toner pickoff apparatus

Citations (11)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3411482A (en) * 1967-01-30 1968-11-19 Varian Associates Electrographic toner development employing a clean-up electrode structure for removing unwanted background
US3412710A (en) * 1966-10-11 1968-11-26 Xerox Corp Cleanup electrode
US3536042A (en) * 1967-03-23 1970-10-27 Xerox Corp Xerographic development apparatus
US3550556A (en) * 1968-01-11 1970-12-29 Xerox Corp Development apparatus
US3574301A (en) * 1969-04-02 1971-04-13 Xerox Corp Developing apparatus
US3592675A (en) * 1967-10-09 1971-07-13 Azoplate Corp Method for developing latent electrostatic images
US3634077A (en) * 1968-08-26 1972-01-11 Xerox Corp Method and apparatus for removing a residual image in an electrostatic copying system
US3637306A (en) * 1970-12-02 1972-01-25 Ibm Copying system featuring alternate developing and cleaning of successive image areas on photoconductor
US3649262A (en) * 1968-12-31 1972-03-14 Xerox Corp Simultaneous development-cleaning of the same area of an electrostatographic image support surface
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

Family Cites Families (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPS5028023A (fr) * 1973-07-17 1975-03-22

Patent Citations (11)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3412710A (en) * 1966-10-11 1968-11-26 Xerox Corp Cleanup electrode
US3411482A (en) * 1967-01-30 1968-11-19 Varian Associates Electrographic toner development employing a clean-up electrode structure for removing unwanted background
US3536042A (en) * 1967-03-23 1970-10-27 Xerox Corp Xerographic development apparatus
US3592675A (en) * 1967-10-09 1971-07-13 Azoplate Corp Method for developing latent electrostatic images
US3550556A (en) * 1968-01-11 1970-12-29 Xerox Corp Development apparatus
US3634077A (en) * 1968-08-26 1972-01-11 Xerox Corp Method and apparatus for removing a residual image in an electrostatic copying system
US3649262A (en) * 1968-12-31 1972-03-14 Xerox Corp Simultaneous development-cleaning of the same area of an electrostatographic image support surface
US3574301A (en) * 1969-04-02 1971-04-13 Xerox Corp Developing apparatus
US3662711A (en) * 1970-03-19 1972-05-16 Xerox Corp Development apparatus
US3637306A (en) * 1970-12-02 1972-01-25 Ibm Copying system featuring alternate developing and cleaning of successive image areas on photoconductor
US3754962A (en) * 1970-12-21 1973-08-28 Ibm Development of electrostatic images

Cited By (12)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US4041903A (en) * 1974-05-21 1977-08-16 Konishiroku Photo Industry Co., Ltd. Developing device for use in electrophotography
US3988816A (en) * 1974-10-23 1976-11-02 Tdk Electronics Company, Limited Magnet roller for electrostatic record developing device
US3996892A (en) * 1975-02-24 1976-12-14 Xerox Corporation Spatially programmable electrode-type roll for electrostatographic processors and the like
US4110034A (en) * 1976-06-24 1978-08-29 Ricoh Company, Ltd. Drum cleaning apparatus for electrostatic copying machine
DE3014372A1 (de) * 1979-04-18 1980-10-23 Tokyo Shibaura Electric Co Entwicklersystem fuer elektrostatisches kopiergeraet
US4318606A (en) * 1980-01-21 1982-03-09 Burroughs Corporation Magnetic toner imaging-multiplexing apparatus
US5134442A (en) * 1990-07-26 1992-07-28 Xerox Corporation Electrode wire contamination prevention and detection
US5239344A (en) * 1991-01-16 1993-08-24 Ricoh Company, Ltd. Developing roller having insulating and conductive areas
US5115276A (en) * 1991-09-05 1992-05-19 Eastman Kodak Company Magnetic brush development apparatus
US6006048A (en) * 1998-10-02 1999-12-21 Xerox Corporation Wrong-sign toner detection system
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
JPS49106337A (fr) 1974-10-08
CA1029943A (fr) 1978-04-25

Similar Documents

Publication Publication Date Title
US4030447A (en) Developing device
US3759222A (en) Microfield donor with continuously reversing microfields
EP0424180A2 (fr) Appareil d'impression
US4165393A (en) Magnetic brush developing process for electrostatic images
US3865080A (en) Toner pickoff apparatus
US4545325A (en) Developing apparatus
US3911865A (en) Toner pickoff apparatus
US4431296A (en) Developing method and apparatus therefor
US3911864A (en) Toner preloaded magnetic brush development system
US4295443A (en) Developing apparatus for electrostatic copying machine
JPH10319708A (ja) 現像装置
US3795222A (en) Development electrode system
JP2590922B2 (ja) 現像装置
JPS626233B2 (fr)
JPS5945149B2 (ja) 静電潜像の現像方法
JPS63106768A (ja) 乾式現像装置
JPS6329741B2 (fr)
JPH04116679A (ja) 現像剤回収装置
JPH0224135Y2 (fr)
JPS6250822B2 (fr)
JPS5814353Y2 (ja) 多段磁気ブラシ現像装置
JPS60241074A (ja) 現像装置
JPS6246869B2 (fr)
JPS6030946B2 (ja) 現像装置
JPS6362745B2 (fr)