EP0027729B1 - Appareil pour développer une image latente électrostatique - Google Patents

Appareil pour développer une image latente électrostatique Download PDF

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Publication number
EP0027729B1
EP0027729B1 EP80303676A EP80303676A EP0027729B1 EP 0027729 B1 EP0027729 B1 EP 0027729B1 EP 80303676 A EP80303676 A EP 80303676A EP 80303676 A EP80303676 A EP 80303676A EP 0027729 B1 EP0027729 B1 EP 0027729B1
Authority
EP
European Patent Office
Prior art keywords
developer material
development
development zone
magnetic
magnetic field
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
Application number
EP80303676A
Other languages
German (de)
English (en)
Other versions
EP0027729A2 (fr
EP0027729A3 (en
Inventor
Raymond W. Huggins
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
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First worldwide family litigation filed litigation Critical https://patents.darts-ip.com/?family=22199811&utm_source=google_patent&utm_medium=platform_link&utm_campaign=public_patent_search&patent=EP0027729(B1) "Global patent litigation dataset” by Darts-ip is licensed under a Creative Commons Attribution 4.0 International License.
Application filed by Xerox Corp filed Critical Xerox Corp
Publication of EP0027729A2 publication Critical patent/EP0027729A2/fr
Publication of EP0027729A3 publication Critical patent/EP0027729A3/en
Application granted granted Critical
Publication of EP0027729B1 publication Critical patent/EP0027729B1/fr
Expired legal-status Critical Current

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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
    • G03G15/09—Apparatus for electrographic processes using a charge pattern for developing using a solid developer, e.g. powder developer using magnetic brush

Definitions

  • This invention relates to an apparatus for developing an electrostatic latent image recorded on an image bearing member.
  • the apparatus includes magnetic means for transporting an electrically conductive developer material into contact with the image bearing member in a development zone to develop the latent image recorded thereon.
  • the developer material used to develop the latent image comprises toner particles adhering triboelectrically to carrier granules.
  • the carrier granules are electrically conductive. This two component mixture is brought into contact with the latent image. The toner particles are attracted from the carrier granules to the latent image forming a powder image thereof.
  • single component developer materials may be employed. Single component developer materials comprise electrically conductive particles.
  • the carrier granules of the two component mixture and the particles of the single component developer material are magnetic. This permits the use of magnetic brush development in the printing machine.
  • the present invention is intended to provide an alternative way of controlling the conductivity of the developer material.
  • an apparatus for developing an electrostatic latent image which is characterised in that the apparatus has only a single development zone and includes means for adjusting the intensity of the magnetic field produced by said magnetic means in the development zone to control the pressure applied on the developer material in the development zone to apply relatively more or less pressure on the developer material to increase or decrease the electric conductivity of the developer material to enhance development respectively of solid area latent images or line latent images, so as to optimize development as between solid area and line images.
  • the electrophotographic printing machine depicted therein employs a belt 10 having a photoconductive surface 12 deposited on a conductive substrate 14.
  • photoconductive surface 12 comprises a transport layer having small molecules of m-TBD dispersed in a polycarbonate and a generation layer of trigonal selenium.
  • Conductive substrate 14 is made preferably from aluminized Mylar (Trade Mark) which is electrically grounded.
  • Belt 10 moves in the direction of arrow 16 to advance successive portions of photoconductivity surface 12 through the various processing stations disposed about the path of movement thereof.
  • support is provided by stripping roller 18, tension roller 20 and drive roller 22.
  • belt 10 is entrained about stripping roller 18, tension roller 20 and drive roller 22.
  • Drive roller 22 is mounted rotatably and in engagement with belt 10.
  • Roller 22 is coupled to motor 24 by suitable means such as a belt drive.
  • Motor 24 rotates roller 22 to advance belt 10 in the direction of arrow 16.
  • Drive roller 22 includes a pair of opposed, spaced edge guides. The edge guides define a space therebetween which determines the desired path of movement for belt 10.
  • Belt 10 is maintained in tension by a pair of springs (not shown) resiliently urging tension roller 20 against belt 10 with the desired spring force.
  • Both stripping roller 18 and tension roller 20 are mounted rotatably. These rollers act as idlers which rotate freely as belt 10 moves in the direction of arrow 16.
  • a corona generating device indicated generally by the reference numeral 26, charges photoconductive surface 12 of belt 10 to a relatively high, substantially uniform potential.
  • the charged portion of photoconductive surface 12 is advanced through exposure station B.
  • an original document 28 is positioned face-down upon transparent platen 30.
  • Lamps 32 flash light rays onto original document 28.
  • the light rays reflected from original document 28 are transmitted through lens 34 forming a light image thereof.
  • Lens 34 focuses the light image onto charged portion of photoconductive surface 12 to selectively dissipate the charge thereon. This records an electrostatic latent image on photoconductive surface 12 which corresponds to the informational areas contained within the original document.
  • belt 10 advances the electrostatic latent image recorded on photoconductive surface 12 to development station C.
  • a magnetic brush development system indicated generally by the reference numeral 36, transports a developer material into contact with photoconductive surface 12. More specifically, roller 38 advances the developer material into contact with photoconductive surface 12 so as to form a powder image on photoconductive surface 12 of belt 10.
  • a two component developer material or a single component developer material may be employed in development system 36.
  • the detailed structure of magnetic brush development system 36 will be described hereinafter with reference to Figures 2 and 3.
  • Belt 10 then advances the powder image to transfer station D.
  • a sheet of support material 40 is moved into contact with the powder image.
  • the sheet of support material is advanced to transfer station D by a sheet feeding apparatus 42.
  • sheet feeding apparatus 42 includes a feed roll 44 contacting the uppermost sheet of stack 46. Feed roll 44 rotates so as to advance the uppermost sheet from stack 46 into chute 48. Chute 48 directs the advancing sheet of support material into contact with photoconductive surface 12 of belt 10 in a timed sequence so that the powder image developed thereon contacts the advancing sheet of support material at transfer station D.
  • Transfer station D includes a corona generating device 50 which sprays ions onto the backside of sheet 40. This attracts the powder image from photoconductive surface 12 to sheet 40. After transfer, the sheet continues to move in the direction of arrow 52 onto a conveyor (not shown) which advances the sheet to fusing station E.
  • Fusing station E includes a fuser assembly, indicated generally by the reference numeral 54, which permanently affixes the transferred powder image to sheet 40.
  • fuse assembly 54 includes a heated fuser roller 56 and a back-up roller 58.
  • Sheet 40 passes between fuser roller 56 and back-up roller 58 with the powder image contacting fuser roller 56. In this manner, the powder image is permanently affixed to sheet 40.
  • a heated pressure system has been described for fixing the particles to sheet 40, a cold pressure system may be utilized in lieu thereof.
  • chute 60 guides the advancing sheet 40 to catch tray 62 for subsequent removal from the printing machine by the operator.
  • Cleaning station F includes a pre-clean conora generating device (not shown) and a rotatably mounted fibrous brush 64 in contact with photoconductive surface 12.
  • the pre-clean corona generator neutralizes the charge attracting the particles to the photoconductive surface.
  • the particles are then cleaned from photoconductive surface 12 by the rotation of brush 64 in contact therewith.
  • a discharge lamp (not shown) floods photoconductive surface 12 with light to dissipate any residual electrostatic charge remaining thereon prior to the charging thereof for the next successive imaging cycle.
  • any suitable photoconductive member may be used, e.g. a drum.
  • developer roller 38 includes a non-magnetic tubular member 66 journaled for rotation.
  • Tubular member 66 is preferably made from aluminum having the exterior circumferential surface thereof roughened.
  • Tubular member 66 rotates in the direction of arrow 68.
  • Elongated magnetic rod 70 is positioned concentrically within tubular member 66 being spaced from the interior circumferential surface thereof.
  • Magnetic rod 70 has a plurality of magnetic poles impressed thereon. Magnetic rod 70 is capable of being indexed so as to orient the magnetic poles relative to development zone 78. In this way, the intensity of the magnetic field in development zone 78 may be varied.
  • the pressure applied on the developer material in development zone 78 is adjusted to a suitable level so as to obtain the desired conductivity thereof.
  • magnetic rod 70 is indexed so as to orient the poles thereon relative to development zone 78. This adjusts the intensity of the magnetic field in development zone 78 to the desired level. This insures that the pressure applied on the developer material in development zone 78 is at the selected level. In this manner, the conductivity of the developer material is maintained at the desired level.
  • the magnetic field generated by magnetic rod 70 attracts the developer material to the exterior circumferential surface of tubular member 66. As tubular member 66 rotates in the direction of arrow 68, the developer material is moved into contact with photoconductive surface 12 to form a powder image.
  • Voltage source 72 electrically biases tubular member 66 to a suitable magnitude and potential, e.g. between 50 and 350 volts.
  • magnetic rod 70 is made from barium ferrite having magnetic poles impressed about the circumferential surface thereof. The strength of the magnetic poles may also be suitably selected. However, once these poles are at a selected value, only by rotating magnetic rod 70 relative to development zone 78 may the intensity of the magnetic field in the development zone be adjusted.
  • FIG. 3 there is shown the indexing system for magnetic rod 70 and the drive system for tubular member 66.
  • a constant speed motor 80 is coupled to tubular member 66.
  • Tubular member 66 is mounted on suitable bearings so as to be rotatable.
  • Magnetic rod 70 is also mounted on suitable bearings being coupled to stepping or indexing motor 82.
  • Energization of stepping motor 82 rotates magnetic rod 70 through a discrete angle so as to orient the magnetic poles impressed thereon relative to the development zone.
  • the intensity of the magnetic field in the development zone is controlled so as to maintain the pressure applied on the developer material at the desired level. This, in turn, regulates the conductivity of the developer material in the development zone.
  • Excitation of motor 80 rotates tubular member 66 in the direction of arrow 68 ( Figure 2) and transports the developer material in the same direction.
  • a suitable two component developer material comprises magnetic, electrically conductive carrier granules having toner particles adhering thereto triboelectrically.
  • the carrier granules include a ferromagnetic core having a thin layer of magnetite overcoated with a layer of resinous material.
  • Suitable resins include poly(vinylidene fluoride) and poly(vinylidene fluoride-co-tetrafluoroethylene).
  • the developer composition can be prepared by mixing the carrier granules with the toner particles.
  • Suitable toner particles are prepared by finely grinding a resinous material and mixing it with the coloring material.
  • the resinous material may be a vinyl polymer such as polyvinyl chloride, polyvinylidene chloride, polyvinyl acetate, polyvinyl acetals, polyvinyl ether, and polyacrylic.
  • Suitable coloring materials may be, amongst others, chromogen black and solvent black.
  • the developer material comprises about 95 to about 99% by weight of carrier and from about 5 to about 1% by weight of toner, respectively.
  • FIG 4 there is shown a logarithmic plot of conductivity as a function of pressure.
  • the graph of Figure 4 reflects a developer roll spacing with respect to the photoconductive surface of about 4 millimeters.
  • the conductivity varies from about 2 x 10-10 (ohm-centimeter ⁇ -1 at a pressure of about 45 newton/meter 2 to about 4 x 10 -8 (ohm-centimeter)-' at a pressure of about 3000 newton/meter 2.
  • the radial magnetic field is about 290 gauss with the tangential magnetic field being about 320 gauss.
  • the pressure on the developer material can be varied not only by changing the magnetic field strength but also by changing the mass flow rate.
  • Mass flow rate may be regulated by controlling the quantity of material or flow rate.
  • the quantity of particles in the development zone is regulated.
  • the angular velocity of the developer roller may be regulated to control the flow of particles. In either case it is clear that the conductivity of the developer material varies as a function of the pressure applied thereon in the development zone.
  • the development apparatus of the present invention optimizes development by regulating the pressure applied on the developer material in the development zone so as to control the conductivity of the developer thereat.
  • the pressure is controlled by regulating the intensity of the magnetic field in the development zone. In this manner, both the solid areas and lines of an electrostatic latent image may be optimumly developed.

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  • Physics & Mathematics (AREA)
  • General Physics & Mathematics (AREA)
  • Dry Development In Electrophotography (AREA)
  • Magnetic Brush Developing In Electrophotography (AREA)

Claims (5)

1. Appareil pour développer une image électrostatique latente enregistrée sur un élément (10) de support d'image avec un matériau révélateur conducteur de l'électricité, comprenant:
- un moyen magnétique (38) pour acheminer le matériau révélateur conducteur de l'électricité et l'amener en contact avec l'élément (10) de support d'image dans une zone de développement (78) de manière à développer l'image latente enregistrée sur cet élément, caractérisé en ce que l'appareil ne comporte qu'une seule zone de développement et comporte un moyen (82) pour régler l'intensité du champ magnétique produit par le moyen magnétique (38) dans la zone de développement (78) afin de commander la pression appliquée au matériau révélateur dans la zone de développement (78) afin d'exercer une pression relativement plus grande ou plus petite sur le matériau révélateur dans le but d'augmenter ou de diminuer la conductibilité électrique du matériau révélateur dans l'objectif de renforcer le développement, respectivement, des images latentes de la surface solide ou des images latentes de lignes, afin d'optimiser le développement par exemple entre images de zone solide et de lignes.
2. Appareil selon la revendication 1, caractérisé en ce que le moyen d'acheminement (38) comprend un élément tubulaire (66) monté de manière à pouvoir tourner, et un élément allongé (70) qui est disposé à l'intérieur de l'élément tubulaire (66) et comporte une pluralité de pôles magnétiques.
3. Appareil selon la revendication 2, caractérisé en ce que le moyen de réglage (82) comprend un moyen pour orienter l'élément allongé afin de positionner les pôles magnétiques par rapport à la zone de développement dans le but d'adjuster l'intensité du champ magnétique dans la zone de développement.
4. Appareil d'impression électrophoto- graphique du type dans lequel une image électrostatique latente est enregistrée sur une surface photoconductrice, comportant un appareil pour le développement de l'image en conformité avec l'une quelconque des revendications 1 à 3.
5. Procédé de développement d'une image électrostatique latente enregistrée sur un élément (10) de support d'image avec un matériau révélateur conducteur de l'électricité, comprenant les étapes suivantes:
- l'acheminement du matériau révélateur conducteur de l'électricité pour l'amener en contact avec l'élément de support d'image dans une zone de développement (78) sur un élément tubulaire en rotation (66) par production d'un champ magnétique de manière à attirer le matériau révélateur vers l'élément tubulaire, caractérisé par:
- le réglage de l'intensité du champ magnétique dans la zone de développement pour commander la pression appliquée au matériau révélateur dans la zone de développement afin d'exercer une pression relativement plus grande ou plus petite sur la matériau révélateur dans le but d'augmenter ou de diminuer la conductibilité électrique du matériau révélateur et renforcer le développement, respectivement, des images latentes dans la zone solide ou des images latentes de lignes, afin d'optimiser le développement par exemple entre images de zone solide et images de ligne.
EP80303676A 1979-10-19 1980-10-17 Appareil pour développer une image latente électrostatique Expired EP0027729B1 (fr)

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
US8662479A 1979-10-19 1979-10-19
US86624 1979-10-19

Publications (3)

Publication Number Publication Date
EP0027729A2 EP0027729A2 (fr) 1981-04-29
EP0027729A3 EP0027729A3 (en) 1981-05-20
EP0027729B1 true EP0027729B1 (fr) 1984-06-13

Family

ID=22199811

Family Applications (1)

Application Number Title Priority Date Filing Date
EP80303676A Expired EP0027729B1 (fr) 1979-10-19 1980-10-17 Appareil pour développer une image latente électrostatique

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Country Link
EP (1) EP0027729B1 (fr)
JP (1) JPS5666862A (fr)
CA (1) CA1150573A (fr)
DE (1) DE3068234D1 (fr)

Families Citing this family (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US4398496A (en) * 1982-07-16 1983-08-16 Xerox Corporation Multi-roll development system
JP2848983B2 (ja) * 1991-03-29 1999-01-20 株式会社フジタ 高層建築物用風力発電装置

Citations (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
EP0019380A1 (fr) * 1979-04-27 1980-11-26 Xerox Corporation Appareil pour développer une image latente

Family Cites Families (9)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3455276A (en) * 1967-05-23 1969-07-15 Minnesota Mining & Mfg Magnetically responsive powder applicator
US3641969A (en) * 1969-12-18 1972-02-15 Plastic Coating Corp Toner unit for photoelectrostatic reproduction
CH549824A (de) * 1972-12-08 1974-05-31 Turlabor Ag Verfahren fuer die steuerung einer magnetischen buerste und vorrichtung zur ausfuehrung des verfahrens.
JPS5917829B2 (ja) * 1975-11-26 1984-04-24 株式会社リコー フクシヤキニオケル ジキブラシゲンゾウホウ オヨビ ソウチ
JPS5949588B2 (ja) * 1975-12-02 1984-12-04 株式会社リコー デンシシヤシンフクシヤホウホウ
JPS52153448A (en) * 1976-06-16 1977-12-20 Fuji Xerox Co Ltd Magnetic brush developing device
DE2654848C2 (de) * 1976-12-03 1978-12-21 Olympia Werke Ag, 2940 Wilhelmshaven Vorrichtung zur Magnetbürstenentwicklung von elektrostatischen Ladungsbildern
JPS6024943B2 (ja) * 1977-09-16 1985-06-15 富士ゼロックス株式会社 磁気刷子現像装置
JPS54116233A (en) * 1978-02-24 1979-09-10 Hitachi Metals Ltd Developing method

Patent Citations (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
EP0019380A1 (fr) * 1979-04-27 1980-11-26 Xerox Corporation Appareil pour développer une image latente

Also Published As

Publication number Publication date
EP0027729A2 (fr) 1981-04-29
JPS5666862A (en) 1981-06-05
EP0027729A3 (en) 1981-05-20
CA1150573A (fr) 1983-07-26
DE3068234D1 (en) 1984-07-19

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