US3929098A - Toner loading for touchdown donor - Google Patents

Toner loading for touchdown donor Download PDF

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Publication number
US3929098A
US3929098A US419732A US41973273A US3929098A US 3929098 A US3929098 A US 3929098A US 419732 A US419732 A US 419732A US 41973273 A US41973273 A US 41973273A US 3929098 A US3929098 A US 3929098A
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particles
carrier particles
sump
toner
development system
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US419732A
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Alan J Liebman
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Xerox Corp
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Xerox Corp
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Priority to US419732A priority Critical patent/US3929098A/en
Priority to CA208,700A priority patent/CA1047246A/en
Priority to GB48996/74A priority patent/GB1490210A/en
Priority to JP49134170A priority patent/JPS5087334A/ja
Priority to FR7439079A priority patent/FR2252596B1/fr
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    • G—PHYSICS
    • G03—PHOTOGRAPHY; CINEMATOGRAPHY; ANALOGOUS TECHNIQUES USING WAVES OTHER THAN OPTICAL WAVES; ELECTROGRAPHY; HOLOGRAPHY
    • G03G—ELECTROGRAPHY; ELECTROPHOTOGRAPHY; MAGNETOGRAPHY
    • G03G15/00—Apparatus for electrographic processes using a charge pattern
    • G03G15/06—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
    • G03G15/0806—Apparatus for electrographic processes using a charge pattern for developing using a solid developer, e.g. powder developer on a donor element, e.g. belt, roller
    • G03G15/0808—Apparatus for electrographic processes using a charge pattern for developing using a solid developer, e.g. powder developer on a donor element, e.g. belt, roller characterised by the developer supplying means, e.g. structure of developer supply roller
    • G—PHYSICS
    • G03—PHOTOGRAPHY; CINEMATOGRAPHY; ANALOGOUS TECHNIQUES USING WAVES OTHER THAN OPTICAL WAVES; ELECTROGRAPHY; HOLOGRAPHY
    • G03G—ELECTROGRAPHY; ELECTROPHOTOGRAPHY; MAGNETOGRAPHY
    • G03G2215/00—Apparatus for electrophotographic processes
    • G03G2215/06—Developing structures, details
    • G03G2215/0602—Developer
    • G03G2215/0604—Developer solid type
    • G03G2215/0614—Developer solid type one-component
    • G—PHYSICS
    • G03—PHOTOGRAPHY; CINEMATOGRAPHY; ANALOGOUS TECHNIQUES USING WAVES OTHER THAN OPTICAL WAVES; ELECTROGRAPHY; HOLOGRAPHY
    • G03G—ELECTROGRAPHY; ELECTROPHOTOGRAPHY; MAGNETOGRAPHY
    • G03G2215/00—Apparatus for electrophotographic processes
    • G03G2215/06—Developing structures, details
    • G03G2215/0634—Developing device
    • G03G2215/0636—Specific type of dry developer device
    • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y10—TECHNICAL SUBJECTS COVERED BY FORMER USPC
    • Y10S—TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y10S101/00—Printing
    • Y10S101/37—Printing employing electrostatic force

Definitions

  • a toner laden rotating donor member (which may be a roller or an endless belt) is located adjacent to a moving photoreceptive surface bearing a latent electrostatic image thereon.
  • the donor member is spaced from the photoreceptor so that a gap of about to 8 'mils exists between the toner layer surface and the photoreceptive surface.
  • the toner on the donor member is given a charge in polarity opposite to the polarity of the electrostatic latent image; As the donor member carries toner past the latent image, the toner is attracted from the donor to the image to develop the image.
  • One of the main problems in prior touchdown development systems is loading the donor roll with an adequate amount of toner to provide a developed image of an acceptable density.
  • a more detailed relatedobject is to provide a method and meansfor loading the donor member with a generally uniform layer of toner particles which will result in a generally uniform development of the electrostatic latent image.
  • the sole figure is a schematic view of a touchdown development system.
  • a xerographic photoreceptor plate is in the form of a drum 10 which passes through stations A-E in the direction shown by the arrow.
  • the drum has a suitable photosensitive surface on which a latent electrostatic image can be formed.
  • a plurality of stations about the periphery of the drum which carry out the reproduction process are: charging station A, exposing station B, developing station C, transfer station D, and cleaning station E. These stations represent conventional means for carrying out their respective functions and do not form a part of the present invention.
  • a corona charging device 12 places a uniform electrostatic charge on the photosensitive material.
  • a light pattern by a suitable exposing apparatus 14, is exposed onto the charged surface of the drum 10.
  • the latent image thereby formed on the surface of the drum is developed by the application of toner particles 15 by a donor member 16 at the developing station C. After the image is developed at station C, it passes through transfer stationD, wherein the toner is transferred to a sheet 17.
  • a corona charging device 18 is utilized in the normal way to facilitate transfer and fuser device 20 is provided to fuse the toner to sheet 17. Following transfer of the developed image to the copy sheet, the drum rotates through cleaning station E, comprising cleaning brush,22 which cleans residual toner particles from the drum 10.
  • a developer sump 26 containing a developer mix 28 therein is located below the donor member 16.
  • the developer mix comprises toner particles 15 and ferromagnetic carrier particles.
  • the toner particles and the carrier particles are selected that the toner particles will become triboelectrically charged to'a polarity op posite the charge of the latentimage upon mixing with the carrier particles. In this particular instance, if the charge of the latent image is positive then the triboelectric charge on the tonerparticles will be selected to be negative.
  • Any type of agitating means may be provided for agitating the developer mix in the sump -to create the proper triboelectric charge on the toner particles.
  • a magnetic brush in the form of a cylinder housing.30 is provided between the donor 16 .and the developer.
  • a pickup magnet- 3l ,and a developing magnet 32 are provided on a stationary iron keeper 33 within the cylinder housing 30.
  • the magnets, 31 and 32 are arranged so that, upon rotation of the cylinder housing 30 through the developerbed, magnetic carrier particles with toner triboelectrically attached thereto will be picked up by the cylinder housing at those portions corresponding to the magnetic field of pickup magnet 31-and brought adjacent to the outer surface of the donor member 16 and within the magnetic field of development magnet 32. which causes thedeveloper bristles on the brush 30 to become erect.
  • the unused toner particles as well as the magnetic carrier particles carried thereby are brought outof thefleld of the magnet 32 whereby they fall bygravity back into the developer sump where the carrier particles can be retoned with toner particles.
  • the magnetic brush 30 In order to create an electrical field for developing or loading the donor 16 with toner particles, and assuming that the latent image carries a positive charge, the magnetic brush 30 is biased to 6OO volts and the donor 16 is biased to +200 volts which is approximately the background potential on the drum 10. This field effects transfer of the negative toner particleslS to the donor 16 from the carrier particles as the developer is pres ented to the donor by the magnetic brush 30.
  • a carrier trap 36 which is in the form of a magnetic roller, is rotatably located adjacent the drum to pick off any carrier particles 38 which may be on the donor 16.
  • a scraper member 40 engages the roller 36 to scrape any carrier particles on the roller 36 therefrom.
  • the carrier particles 38 scraped from the pick-off roller 36 fall by gravity back into the sump 26 for retoning.
  • a scraper member 42 is provided to scrape residual toner particles from the donor 16 which fall back into the sump 26.
  • the carrier particle size distribution should be such that at least 85%, preferably 95%, of all of the particles, by volume, are less than 50 microns average diameter and preferably between and 50 microns. This is necessary in order to coat the donor [6 with a generally uniform layer of toner particles. It has been found that when larger size carrier particles are utilized, numerous carrier bead tracks which were relatively wide and deep were formed in the toner layer on the donor drum 16. When carrier particles of the size specified above are utilized, thinner and shallower carrier tracks were formed in the deposited toner layer which were insignificant insofar as disturbing the uniformity of the toner layer on the donor drum 16.
  • a development system for developing latent electrostaticimages carried by a photoreceptor of an electrostatic processor comprising the combination of a sump for storing a supply of developer, said developer including ferromagnetic carrier particles having toner particles triboelectrically attracted thereto; a rotatable doner member positioned adjacent said photoreceptor for applying toner particles. to said photoreceptor in conformity with said latent images; magnetic means disposed between said sump and said doner member for loading said doner member with toner particles; and means coupled to said doner member and said magnetic means for creating an electrostatic field between said magnetic means and said doner member for stripping the toner particles from the carrier particles during the loading of said doner member.
  • a rotatable magnetic means is located adjacent the surface of said doner member to magnetically attract any carrier particles carried by said donor member prior to said carrier particles being presented to said latent image, and means for removing said magnetic particles from said rotatable magnetic means.
  • a development system for developing latent electrostatic images carried by a photoreceptor of an electrostatic processor comprising the combination of a supply of developer including ferromagnetic carrier particles having toner particles triboelectrically attracted thereto, at least 85% by volume of all of said carrier particles having a diameter less than 50 microns; a doner member positioned adjacent said photoreceptor for developing said images with toner particles; and means disposed between said sump and said doner member for removing developer from said sump, stripping toner particles from the carrier particles of said removed developer and loading said toner member with a substantially uniform layer of said stripped toner particles.

Abstract

In an electrostatic development system, developer material in a sump comprises a mix of toner particles adhered to magnetic carrier particles. A transfer member, disposed in the trough of the sump, removes developer material in the form of a magnetic brush. A doner member, operatively associated with the transfer member and a photoreceptor having the electrostatic latent image to be developed, is biased whereby to strip toner particles from the carrier particles on said transfer member and to deliver said stripped toner particles to the latent image.

Description

United States Patent [191 Liebman TONER LOADING FOR TOUCHDOWN DONOR [75] Inventor: Alan J. Liebman, Rochester, NY.
[73] Assignee: Xerox Corporation, Stamford,
Conn.
22 Filed: Nov. 28, 1973 21 Appl. No.: 419,732
[52] US. Cl 118/637; 101/DIG. 13; 346/74 ES; 355/3 DD [51] Int. Cl. G03G 13/06 [58] Field of Search 96/1 SD; 117/175; 1l8/637; l0l/DIG. 13; 346/74 ES; 355/3 DD [56] References Cited UNITED STATES PATENTS 10/1968 King et al. 118/637 5/1971 Yang 355/15 Dec. 30, 1975 3,654,902 4/1972 Hakanson 118/637 3,696,783 10/1972 Fantuzzo ll8/637 3,759,222 9/1973 Maksymiak et al 1. 118/637 Primary ExaminerMorris Kaplan 571 ABSTRACT 6 Claims, 1 Drawing Figure US. Patent Dec. 30, 1975 3,929,098
TONER LOADING FOR TOUCHDOWN DONOR DESCRIPTIONOF THE INVENTION 1 This invention is concerned with an improvement to a touchdown development system. The term touchdown development as used in thisapplication refers to the following system: i l
A toner laden rotating donor member (which may be a roller or an endless belt) is located adjacent to a moving photoreceptive surface bearing a latent electrostatic image thereon. The donor member is spaced from the photoreceptor so that a gap of about to 8 'mils exists between the toner layer surface and the photoreceptive surface. The toner on the donor member is given a charge in polarity opposite to the polarity of the electrostatic latent image; As the donor member carries toner past the latent image, the toner is attracted from the donor to the image to develop the image.
One of the main problems in prior touchdown development systems is loading the donor roll with an adequate amount of toner to provide a developed image of an acceptable density.
It is an object of this invention to provide means to load a donor roll with an adequate amount of' toner which will result in the development of 'an electrostatic latent image with an acceptable density.
It is a further object of .this invention to provide means for loading a donor member with. an adequate amount of toner which will result in the development of an electrostatic latent image of acceptable density. A more detailed relatedobject is to provide a method and meansfor loading the donor member with a generally uniform layer of toner particles which will result in a generally uniform development of the electrostatic latent image. P
It is stilla further object of the invention to provide a touchdown development system where unused toner particles returned to a developer sump after being presented to a latent image are not agglomerated.
Other objects of this invention will become apparent from the following description with reference to the drawing wherein:
The sole figure is a schematic view of a touchdown development system.
Referring to the drawing, there is shown a xerographic reproduction system utilizing the concept of the present invention. In this apparatus, a xerographic photoreceptor plate is in the form of a drum 10 which passes through stations A-E in the direction shown by the arrow. The drum has a suitable photosensitive surface on which a latent electrostatic image can be formed. A plurality of stations about the periphery of the drum which carry out the reproduction process are: charging station A, exposing station B, developing station C, transfer station D, and cleaning station E. These stations represent conventional means for carrying out their respective functions and do not form a part of the present invention.
At station A, a corona charging device 12 places a uniform electrostatic charge on the photosensitive material. As the drum 10 rotates, a light pattern, by a suitable exposing apparatus 14, is exposed onto the charged surface of the drum 10. The latent image thereby formed on the surface of the drum is developed by the application of toner particles 15 by a donor member 16 at the developing station C. After the image is developed at station C, it passes through transfer stationD, wherein the toner is transferred to a sheet 17.
A corona charging device 18 is utilized in the normal way to facilitate transfer and fuser device 20 is provided to fuse the toner to sheet 17. Following transfer of the developed image to the copy sheet, the drum rotates through cleaning station E, comprising cleaning brush,22 which cleans residual toner particles from the drum 10.
A developer sump 26 containing a developer mix 28 therein is located below the donor member 16. The developer mix comprises toner particles 15 and ferromagnetic carrier particles. The toner particles and the carrier particles are selected that the toner particles will become triboelectrically charged to'a polarity op posite the charge of the latentimage upon mixing with the carrier particles. In this particular instance, if the charge of the latent image is positive then the triboelectric charge on the tonerparticles will be selected to be negative. Any type of agitating means may be provided for agitating the developer mix in the sump -to create the proper triboelectric charge on the toner particles. A magnetic brush in the form of a cylinder housing.30 is provided between the donor 16 .and the developer. sump 26 and arrangedthat a portion thereof will rotate through the developer mix. A pickup magnet- 3l ,and a developing magnet 32 are provided on a stationary iron keeper 33 within the cylinder housing 30. The magnets, 31 and 32 are arranged so that, upon rotation of the cylinder housing 30 through the developerbed, magnetic carrier particles with toner triboelectrically attached thereto will be picked up by the cylinder housing at those portions corresponding to the magnetic field of pickup magnet 31-and brought adjacent to the outer surface of the donor member 16 and within the magnetic field of development magnet 32. which causes thedeveloper bristles on the brush 30 to become erect. Upon further rotation of the magnetic brush 30, the unused toner particles as well as the magnetic carrier particles carried thereby are brought outof thefleld of the magnet 32 whereby they fall bygravity back into the developer sump where the carrier particles can be retoned with toner particles. g
If only toner particles were present inthedeveloper system, agglomeration of the toner particles would tend to occur in a toner bed during rotation of the cylinder 30 therethrough and upon presentation of the toner particles by cylinder 30 to the donor 16 and by the cylinder 30 to a latent image with the unused toner falling back into the sump being agglomerated. However, the presence of carrier particles in the development system helps to prevent this tendency to agglomerate.
In order to create an electrical field for developing or loading the donor 16 with toner particles, and assuming that the latent image carries a positive charge, the magnetic brush 30 is biased to 6OO volts and the donor 16 is biased to +200 volts which is approximately the background potential on the drum 10. This field effects transfer of the negative toner particleslS to the donor 16 from the carrier particles as the developer is pres ented to the donor by the magnetic brush 30.
Since there is a possibility that the carrier particles may be mechanically impressed onto the donor, a carrier trap 36, which is in the form of a magnetic roller, is rotatably located adjacent the drum to pick off any carrier particles 38 which may be on the donor 16. A scraper member 40 engages the roller 36 to scrape any carrier particles on the roller 36 therefrom. The carrier particles 38 scraped from the pick-off roller 36 fall by gravity back into the sump 26 for retoning. A scraper member 42 is provided to scrape residual toner particles from the donor 16 which fall back into the sump 26.
The carrier particle size distribution should be such that at least 85%, preferably 95%, of all of the particles, by volume, are less than 50 microns average diameter and preferably between and 50 microns. This is necessary in order to coat the donor [6 with a generally uniform layer of toner particles. It has been found that when larger size carrier particles are utilized, numerous carrier bead tracks which were relatively wide and deep were formed in the toner layer on the donor drum 16. When carrier particles of the size specified above are utilized, thinner and shallower carrier tracks were formed in the deposited toner layer which were insignificant insofar as disturbing the uniformity of the toner layer on the donor drum 16. It is very advantageous to essentially eliminate the carrier bead tracks in the toner layer'since those areas of the latent image which correspond to the tracks as the toner layer is presented thereto will not be developed or at the most will be just slightly developed resulting in a poor copy in those developed areas. For instance, a typical line type written'char'acter is about 250 microns wide. It has been foundthat with a carrier bead track in a toner layer which is greater than about 20% of the character line width,there is a good chance that some of or all of the character will be lost in development. Thus, the use of carrier particles or beads of the size specified above assures that the character will not be partially or fully lost during-development of the latent image.
What is claimed is:
l. A development system for developing latent electrostaticimages carried by a photoreceptor of an electrostatic processor; said development system comprising the combination of a sump for storing a supply of developer, said developer including ferromagnetic carrier particles having toner particles triboelectrically attracted thereto; a rotatable doner member positioned adjacent said photoreceptor for applying toner particles. to said photoreceptor in conformity with said latent images; magnetic means disposed between said sump and said doner member for loading said doner member with toner particles; and means coupled to said doner member and said magnetic means for creating an electrostatic field between said magnetic means and said doner member for stripping the toner particles from the carrier particles during the loading of said doner member.
2. The development system of claim 1 wherein a rotatable magnetic means is located adjacent the surface of said doner member to magnetically attract any carrier particles carried by said donor member prior to said carrier particles being presented to said latent image, and means for removing said magnetic particles from said rotatable magnetic means.
3. The development system of claim 1 wherein the size distribution of said carrier particles is such that at least by volume, of all of the carrier particles in said sump are of a diameter less than 50 microns.
4. The development system of claim 3 wherein at least 85% by volume of all of said carrier particles in said sump are of a diameter between 10 and 50 microns.
5. A development system for developing latent electrostatic images carried by a photoreceptor of an electrostatic processor; said development system comprising the combination of a supply of developer including ferromagnetic carrier particles having toner particles triboelectrically attracted thereto, at least 85% by volume of all of said carrier particles having a diameter less than 50 microns; a doner member positioned adjacent said photoreceptor for developing said images with toner particles; and means disposed between said sump and said doner member for removing developer from said sump, stripping toner particles from the carrier particles of said removed developer and loading said toner member with a substantially uniform layer of said stripped toner particles.
6. The development system of claim 5 wherein at least 85% by volume of all of said carrier particles in said sump are of a diameter between 10 and 50 microns.

Claims (6)

1. A DEVELOPMENT SYSTEM FOR DEVELOPING LATENT ELECTROSTATIC IMAGES CARRIED BY A PHOTORECEPTOR FOR AN ELECTROSTATIC PROCESSOR; SAID DEVELOPMENT SYSTEM COMPRISING THE COMBINATION OF A SUMP FOR STORING A SUPPLY OF DEVELOPER, SAID DEVELOPER INCLUDING FERROMAGNETIC CARRIER PARTICLES HAVING TONER PARTICLES TRIBOELECTRICALLY ATTRACTED THERETO; A ROTATABLE DONER MEMBER POSITIONED ADJACENT SAID PHOTORECEPTOR FOR APPLYING TONER PARTICLES TO SAID PHOTORECEPTOR IN CONFORMITY WITH SAID LATENT IMAGES; A MAGNETIC MEANS DISPOSED BETWEEN SAID SUMP AND SAID DONER MEMBER FOR LOADING SAID DONER MEMBER WITH TONER PARTICLES; AND MEANS COUPLED TO SAID DONER MEMBER AND SAID MAGNETIC MEANS FOR CREATING AN ELECTROSTATIC FIELD BETWEEN SAID MAGNETIC MEANSS AND SAID DONER MEMBER FOR STRIPPING THE TONER PARTICLES FROM THE CARRIER PARTICLES DURING THE LOADING OF SAID DONER MEMBER.
2. The development system of claim 1 wherein a rotatable magnetic means is located adjacent the surface of said doner member to magnetically attract any carrier particles carried by said donor member prior to said carrier particles being presented to said latent image, and means for removing said magnetic particles from said rotatable magnetic means.
3. The development system of claim 1 wherein the size distribution of said carrier particles is such that at least 85%, by volume, of all of the carrier particles in said sump are of a diameter less than 50 microns.
4. The development system of claim 3 wherein at least 85% by volume of all of said carrier particles in said sump are of a diameter between 10 and 50 microns.
5. A development system for developing latent electrostatic images carried by a photoreceptor of an electrostatic processor; said development system comprising the combination of a supply of developer including ferromagnetic carrier particles having toner particles triboelectrically attracted thereto, at least 85% by volume of all of said carrier particles having a diameter less than 50 microns; a doner member positioned adjacent said photoreceptor for developing said images with toner particles; and means disposed between said sump and said doner member for removing developer from said sump, stripping toner particles from the carrier particles of said removed developer and loading said toner member with a substantially uniform layer of said stripped toner particles.
6. The development system of claim 5 wherein at least 85% by volume of all of said carrier particles in said sump are of a diameter between 10 and 50 microns.
US419732A 1973-11-28 1973-11-28 Toner loading for touchdown donor Expired - Lifetime US3929098A (en)

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Application Number Priority Date Filing Date Title
US419732A US3929098A (en) 1973-11-28 1973-11-28 Toner loading for touchdown donor
CA208,700A CA1047246A (en) 1973-11-28 1974-09-09 Toner loading for touchdown donor
GB48996/74A GB1490210A (en) 1973-11-28 1974-11-12 Apparatus for developing an electrostatic latent image
JP49134170A JPS5087334A (en) 1973-11-28 1974-11-21
FR7439079A FR2252596B1 (en) 1973-11-28 1974-11-28

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CA (1) CA1047246A (en)
FR (1) FR2252596B1 (en)
GB (1) GB1490210A (en)

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US5032872A (en) * 1989-10-30 1991-07-16 Xerox Corporation Developing device with dual donor rollers including electrically biased electrodes for each donor roller
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US5177323A (en) * 1990-10-31 1993-01-05 Kabushiki Kaisha Toshiba Developing device for developing an electrostatic latent image by a one-component developing agent
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EP0601786A2 (en) * 1992-12-07 1994-06-15 Xerox Corporation Proper charging of donor roll in hybrid development
US5416567A (en) * 1992-06-30 1995-05-16 Sharp Kabushiki Kaisha Developing device and a developing method having a conductive member upstream of image data forming member
EP0725322A1 (en) * 1995-02-03 1996-08-07 Hewlett-Packard Company Dry development process with liquid toner
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US20040022549A1 (en) * 2002-03-26 2004-02-05 Yoshio Ozawa Image forming apparatus and image forming method
DE10246022B3 (en) * 2002-10-02 2004-07-22 OCé PRINTING SYSTEMS GMBH Apparatus and method for collecting magnetizable carrier particles from a mixture of toner particles and magnetizable carrier particles
US20060024092A1 (en) * 2004-07-30 2006-02-02 Kyocera Mita Corporation Developing device
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US20080292365A1 (en) * 2007-05-25 2008-11-27 Kyocera Mita Corporation Image forming apparatus and developing device
US20090003891A1 (en) * 2007-06-27 2009-01-01 Kyocera Mita Corporation Image forming apparatus
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US4036175A (en) * 1976-03-30 1977-07-19 Sperry Rand Corporation High speed development technique
US4101909A (en) * 1976-07-30 1978-07-18 Epp Corp. Magnetic inking apparatus for pulsed electrical printing
US4103306A (en) * 1976-07-30 1978-07-25 Epp Corp. Non-impact printer with magnetic ink reorientation
DE2800056A1 (en) * 1977-01-05 1978-07-13 Xerox Corp REPRODUCTION MACHINE, AS WELL AS ELECTROPHOTOGRAPHIC PRINTING MACHINE
US4230070A (en) * 1977-08-24 1980-10-28 Minolta Camera Kabushiki Kaisha Device for automatically replenishing toner to dry-type developing apparatus for electrophotography
US4295442A (en) * 1978-08-04 1981-10-20 Sperry Corporation Magnetic toner apparatus
US4378158A (en) * 1979-07-16 1983-03-29 Canon Kabushiki Kaisha Developing apparatus
US4383497A (en) * 1979-09-11 1983-05-17 Canon Kabushiki Kaisha Developing device
DE3034093A1 (en) * 1979-09-11 1981-04-02 Canon K.K., Tokyo DEVELOPMENT DEVICE
EP0026677A1 (en) * 1979-10-01 1981-04-08 Xerox Corporation Magnetic photoreceptor cleaning system
EP0026677B1 (en) * 1979-10-01 1984-05-09 Xerox Corporation Magnetic photoreceptor cleaning system
US4511268A (en) * 1979-10-19 1985-04-16 Marshall Eric J High speed printer
DE3108194A1 (en) * 1980-03-04 1981-12-24 Canon K.K., Tokyo DEVELOPMENT PROCESS AND DEVELOPMENT DEVICE
US4487496A (en) * 1981-05-13 1984-12-11 Siemens Aktiengesellschaft Device for adjusting the level of a developing mixture, which consists of a toner and carrier particles, on a developing roller
DE3329497A1 (en) * 1982-08-16 1984-03-15 Tokyo Shibaura Denki K.K., Kawasaki DEVELOPMENT DEVICE
JPH0430589B2 (en) * 1982-12-28 1992-05-22
JPS59121347A (en) * 1982-12-28 1984-07-13 Toshiba Corp Developing device
US4743937A (en) * 1983-12-12 1988-05-10 Xerox Corporation Apparatus for charging toner particles
EP0322940A1 (en) * 1987-12-07 1989-07-05 Agfa-Gevaert N.V. Dry toner development
EP0414455A3 (en) * 1989-08-21 1991-08-07 Xerox Corporation Hybrid development system
EP0414455A2 (en) * 1989-08-21 1991-02-27 Xerox Corporation Hybrid development system
US5032872A (en) * 1989-10-30 1991-07-16 Xerox Corporation Developing device with dual donor rollers including electrically biased electrodes for each donor roller
EP0435566A2 (en) * 1989-12-26 1991-07-03 Xerox Corporation Electrostatographic apparatus
EP0435566A3 (en) * 1989-12-26 1993-01-13 Xerox Corporation Electrostatographic apparatus
US5063875A (en) * 1990-03-19 1991-11-12 Xerox Corporation Development apparatus having a transport roll rotating at least twice the surface velocity of a donor roll
US5177323A (en) * 1990-10-31 1993-01-05 Kabushiki Kaisha Toshiba Developing device for developing an electrostatic latent image by a one-component developing agent
US5270782A (en) * 1991-12-23 1993-12-14 Xerox Corporation Single-component development system with intermediate donor member
US5416567A (en) * 1992-06-30 1995-05-16 Sharp Kabushiki Kaisha Developing device and a developing method having a conductive member upstream of image data forming member
EP0601786A2 (en) * 1992-12-07 1994-06-15 Xerox Corporation Proper charging of donor roll in hybrid development
EP0601786A3 (en) * 1992-12-07 1995-07-19 Xerox Corp Proper charging of donor roll in hybrid development.
US5341197A (en) * 1992-12-07 1994-08-23 Xerox Corporation Proper charging of donor roll in hybrid development
US5634181A (en) * 1993-02-16 1997-05-27 Fuji Xerox Co., Ltd. Developing apparatus
EP0725322A1 (en) * 1995-02-03 1996-08-07 Hewlett-Packard Company Dry development process with liquid toner
US5587224A (en) * 1995-03-27 1996-12-24 Xerox Corporation Developing apparatus including a coated developer roller
US5937236A (en) * 1996-09-11 1999-08-10 Samsung Electronics Co., Ltd. Ghost-image preventing apparatus for a developing roller
US6526248B1 (en) * 1999-09-16 2003-02-25 Ricoh Company, Ltd. Toner support member and developing device prevented from charging toner by friction
US6253053B1 (en) 2000-01-11 2001-06-26 Xerox Corporation Enhanced phenolic developer roll sleeves
US6381848B2 (en) 2000-01-11 2002-05-07 Xerox Corporation Method of making enhanced phenolic developer roll sleeves
US20040002015A1 (en) * 2002-03-15 2004-01-01 Yoshio Ozawa Method for developing in hybrid developing apparatus
US6868240B2 (en) 2002-03-15 2005-03-15 Kyocera Corporation Method for developing in hybrid developing apparatus
US20040022549A1 (en) * 2002-03-26 2004-02-05 Yoshio Ozawa Image forming apparatus and image forming method
US6829448B2 (en) 2002-03-26 2004-12-07 Kyocera Corporation Image forming apparatus and image forming method
DE10246022B3 (en) * 2002-10-02 2004-07-22 OCé PRINTING SYSTEMS GMBH Apparatus and method for collecting magnetizable carrier particles from a mixture of toner particles and magnetizable carrier particles
US20060024092A1 (en) * 2004-07-30 2006-02-02 Kyocera Mita Corporation Developing device
US20080240795A1 (en) * 2004-07-30 2008-10-02 Kyocera Mita Corporation Developing Device Used In An Image Forming Apparatus
US7298995B2 (en) 2004-07-30 2007-11-20 Kyocera Mita Corporation Developing device used in an image forming apparatus
US7742727B2 (en) 2007-03-20 2010-06-22 Kyocera Mita Corporation Image forming apparatus
US20080232860A1 (en) * 2007-03-20 2008-09-25 Kyocera Mita Corporation Image forming apparatus
US20080232859A1 (en) * 2007-03-20 2008-09-25 Kyocera Mita Corporation Image forming apparatus
US20080232862A1 (en) * 2007-03-20 2008-09-25 Kyocera Mita Corporation Image forming apparatus
US7941080B2 (en) 2007-03-20 2011-05-10 Kyocera Mita Corporation Image forming apparatus
CN101271302B (en) * 2007-03-20 2010-11-17 京瓷美达株式会社 Image forming apparatus
US7826781B2 (en) 2007-03-20 2010-11-02 Kyocera Mita Corporation Image forming apparatus with controlled application of alternating-current bias
US20080292365A1 (en) * 2007-05-25 2008-11-27 Kyocera Mita Corporation Image forming apparatus and developing device
US20090003891A1 (en) * 2007-06-27 2009-01-01 Kyocera Mita Corporation Image forming apparatus
US7613417B2 (en) 2007-06-27 2009-11-03 Kyocera Mita Corporation Image forming apparatus
JP2009031749A (en) * 2007-06-27 2009-02-12 Kyocera Mita Corp Image forming apparatus
US20090190970A1 (en) * 2007-07-23 2009-07-30 Ricoh Printing Systems, Ltd. Development Device and Image Forming Apparatus Using the Same
US8073369B2 (en) 2007-07-23 2011-12-06 Ricoh Company, Ltd. Development device transferring only a toner layer to a developing roller and image apparatus using the same

Also Published As

Publication number Publication date
FR2252596B1 (en) 1977-11-04
GB1490210A (en) 1977-10-26
JPS5087334A (en) 1975-07-14
FR2252596A1 (en) 1975-06-20
CA1047246A (en) 1979-01-30

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