EP0166544B1 - Procédé de développement pour électrophotographie en deux couleurs et appareil de développement à cet effet - Google Patents

Procédé de développement pour électrophotographie en deux couleurs et appareil de développement à cet effet Download PDF

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Publication number
EP0166544B1
EP0166544B1 EP19850303870 EP85303870A EP0166544B1 EP 0166544 B1 EP0166544 B1 EP 0166544B1 EP 19850303870 EP19850303870 EP 19850303870 EP 85303870 A EP85303870 A EP 85303870A EP 0166544 B1 EP0166544 B1 EP 0166544B1
Authority
EP
European Patent Office
Prior art keywords
color toner
polarity
sleeve
magnetic
developing roller
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
EP19850303870
Other languages
German (de)
English (en)
Other versions
EP0166544A1 (fr
Inventor
Masahiko Kubo
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.)
Kyocera Mita Industrial Co Ltd
Original Assignee
Mita Industrial Co Ltd
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 Mita Industrial Co Ltd filed Critical Mita Industrial Co Ltd
Publication of EP0166544A1 publication Critical patent/EP0166544A1/fr
Application granted granted Critical
Publication of EP0166544B1 publication Critical patent/EP0166544B1/fr
Expired 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
    • G03G15/0806—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
    • G—PHYSICS
    • G03—PHOTOGRAPHY; CINEMATOGRAPHY; ANALOGOUS TECHNIQUES USING WAVES OTHER THAN OPTICAL WAVES; ELECTROGRAPHY; HOLOGRAPHY
    • G03G—ELECTROGRAPHY; ELECTROPHOTOGRAPHY; MAGNETOGRAPHY
    • G03G13/00—Electrographic processes using a charge pattern
    • G03G13/01—Electrographic processes using a charge pattern for multicoloured copies
    • 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
    • G03G15/01—Apparatus for electrographic processes using a charge pattern for producing multicoloured copies
    • G03G15/0105—Details of unit
    • G03G15/0126—Details of unit using a solid developer
    • 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
    • G03G2215/0619—Developer solid type one-component non-contact (flying development)
    • 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

Definitions

  • This invention relates to two color electrophotography and to the formation of two-color images therein. More particularly, it relates to a developing process for the formation of distinct images having two colors, using two kinds of insulative and non-magnetic color toner and a simple developing unit, and to electrophotographic apparatus for the same.
  • corrections, comments and underlines are made on the original document material or the like by the use of colored pencils (e.g., red pencils) which are distinguishable from the basic color (i.e., black) of the original.
  • red pencils e.g., red pencils
  • the original documents or materials are copied by a copying machine to distribute to subscribers, conference members, etc.
  • corrections, comments and underlines are reproduced in black only, so that the corrections, comments and underlines no longer appear to be emphasized.
  • the colors to be used for such corrections, comments or underlines do not usually have to correspond to the colors in the original, but they are required to be distinguishable from the basic color of the original.
  • photoreceptor Two kinds of photoreceptor have been used for the photoreceptor mentioned above, one of which has a single photosensitive layer and an insulating layer on the photosensitive layer and the other of which has a photosensitive composite composed of two photosensitive layers of different spectral sensitivities.
  • the electrostatic latent images having different polarities are formed by two charging treatments with different polarities and an exposing treatment, followed by a developing using a positively charged developer from a first developing means and a negatively charged developer from a second developing means, resulting in toner images having two colors.
  • the developer is a dual component developer
  • the tip of the brush containing a rigid carrier composed of iron particles or glass beads is in contact with the surface of the photoreceptor, the surface of the photoreceptor is easily damaged.
  • the carrier is electroconductive, electric charges leak at the time when the carrier contacts the latent image on the photoreceptor resulting in a brush mark in the obtained visible image.
  • the developer When the developer is a mono-component toner which is made using a rigid magnetite, etc., it tends to damage the surface of the photoreceptor during cleaning by means of a blade.
  • the electrophotographic process for two-color electrophotography of this invention which overcomes the above-discussed disadvantages and other numerous drawbacks and deficiencies of the prior art, comprises:
  • a bias potential having a polarity different from the polarity of said first color toner is, in a preferred embodiment, applied to the first developing roller.
  • a bias potential having a polarity different from the polarity of said second color toner is, in a preferred embodiment, applied to the second developing roller.
  • An electrophotographic apparatus of this invention which overcomes the above-discussed disadvantages and other numerous drawbacks and deficiencies of the prior art, comprises:
  • the apparatus preferably comprises means for applying a bias potential having a polarity different from the polarity of said first color toner to the first developing roller. Moreover, the apparatus preferably comprises means for applying a bias potential having a polarity different from the polarity of said second colortonerto the second developing roller.
  • the invention described herein makes possible the objects of (1) providing a process for two-color electrophotography wherein a two-color toner image is formed uniformly and reliably on a photoreceptor using a single developing container, resulting in distinct images having two colors (but not a compound color); (2) providing a process for two-color electrophotography wherein developing is simple to carry out; (3) providing an electrophotographic apparatus for the formation of distinct images having two colors, using a single developing container; and (4) providing an electrophotographic apparatus whose developing equipment has a simple structure which makes easy the maintenance thereof.
  • the drawing shows an electrophotographic apparatus of this invention, which comprises a photoreceptor drum 1, a charging means 2 in the vicinity of the drum 1, an exposing means.3 beyond the charging means 2, and a developing means 4 beyond the exposing means 3.
  • any of photoreceptors on which electrostatic latent images are formed and maintained with positive and negative polarities by a known exposure treatment can be used with this invention, an example of which is a photosensitive composite comprising a first photosensitive layer 12 and a second photosensitive layer 13 formed on a conductive substrate 14.
  • the photosensitive layers 12 and 13 have different spectral sensitivities and are made of, for example, inorganic photosensitive substances such as amorphous selenium, zinc oxide, etc., or organic photosensitive substances such as poly- vinylcarbazole, etc., but are not limited thereto.
  • the photosensitive layer made of, for example, amorphous selenium is positively charged due to the p-electroconductivity, while the photosensitive layer made of zinc oxide is negatively charged due to the n-electroconductivity.
  • the conductive substrate 14 supporting the photosensitive layers is made of, for example, a metal such as aluminium, or by disposing an electroconductive substance on a plastic film base by vacuum evaporation deposition, or the like, but is not limited thereto.
  • a dielectric drum instead of the photoreceptor drum 1 can be used for the medium on which electrostatic latent images are formed with positive and negative polarities provided by means of pin electrodes.
  • the charging means 2 and the exposing means 3, respectively, are selected from any means known to be useful for color electrophotography in this invention.
  • An example of the charging means 2 is an AC corona charger or two kinds of corona charger for charging positively and negatively.
  • An example of the exposing means 3 is made up of a light source and an optical system.
  • the developing means 4 comprises a container 42 for containing a developer 41 therein.
  • the container 42 has a holding means 43 for holding the developer 41 on a sleeve 430.
  • the holding means 43 comprises the sleeve 430 and a fixed magnet 431 disposed behind the sleeve 430.
  • the magnet 431 is preferably fixed in order to uniformly adhere the developer 41 to the surface of the sleeve 430.
  • a first developing roller 44 and a second developing roller45 are rotatably disposed between the holding means 43 and the photoreceptor drum 1, and have bias potential application means 440 and 450, respectively. At least the surface of each of the rollers, 44 and 45 is made of a conductive and non-magnetic material such as aluminium.
  • the developer 41 in the container 42 which consists of a first insulative and non-magnetic color toner 411, a second insulative and non-magnetic color toner 412, and a magnetic carrier 413, is mixed by the sleeve 430 or an agitation roller (not shown) such that friction induces an electrostatic charge on the toners and the carrier, the polarities of each of which depend uopn the order of charging tendency therebetween or the dielectric constant of the carrier.
  • the first color toner 411 is, for example, charged with a negative polarity and the second color toner 412 is charged with a positive polarity.
  • the fixed magnet 431 in the holding means 43 serves to adhere the charged developer 41 to the surface of the sleeve 430 and hold it thereon.
  • the sleeve 430 is made of, for example, a conductive and non-magnetic material such as aluminium and is rotatable around the magnet 431.
  • the carrier 413 is made of a magnetic material such as iron particles or the like.
  • a bias potential is applied to each of the first and the second developing rollers 44 and 45 in such a manner that the first and the second developing rollers 44 and 45 are charged with, for example, a positive polarity and a negative polarity, respectively.
  • the developer 41 which consists of two kinds of color toner 411 and 412 and a magnetic carrier 413 charged with a positive or a negative polarity due to friction therebetween, is adhered to the sleeve 430 and held thereon by means of the magnet431 in such a manner that it forms a brush thereon in the direction of magnetic lines of force of the magnet 430.
  • the direction and the density of the magnetic lines of force to the developer 41 on the sleeve 430 vary as the sleeve 430 turns.
  • the magnetic brush rises toward the developing rollers 44 and 45 due to an electrostatic force among the bias potential applied to each of the developing rollers 44 and 45 and the color toners 411 and 412. Due to the bias potential, the first color toner 411 transfers from the sleeve 430 to the first developing roller 44 and is held thereon.
  • the second color toner 412 transfers from the sleeve 430 to the second developing roller 45 and is held thereon, as well. Since the magnetic carrier 413 bearing the second color toner 412 has the same charging polarity as the first color toner 411, the magnetic carrier 413 tends to be attracted toward the first developing roller 44 due to the electrostatic force of the bias potential applied to the roller 44. However, the magnetic carrier 413 is maintained on the sleeve 430 without transferring to the first developing roller 44 because the attraction of magnetic force of the magnet 431 is greater than that of the electrostatic force of the first developing roller 44.
  • the color toners 411 and 412 are carried toward the photoreceptor drum 1 as the developing rollers 44 and 45 turn.
  • electrostatic latent images having polarities, which correspond to the two colors in the original are formed, in advance, by the charging means 2 and the exposing means 3.
  • the first and the second color toner 411 and 412 are transferred from the first and the second developing rollers 44 and 45, respectively, to the electrostatic latent images by a non-contact development such as a "jumping" development, a touch-down development, etc., resulting in a toner image.
  • a thickness-regulation board such as a blade is disposed near the surface of the roller.
  • the toner image is successively formed on the electrostatic latent images thereon.
  • the resulting toner images are then charged with the same polarity by means of a charger down stream of the developing means 4, and electrostatically transferred to a transfer paper in the transfer area, resulting in a distinct image having two colors.
  • the colors of the toners 411 and 412 are not specific because they do not usually have to correspond to the colors in the original, but they are required to be distinguishable from the basic color of the original.
  • the color toner consists of particles having a diameter of from 1 to 50 J , l m which are prepared by dispersing pigments into a resin binder such as styrene resins, acrylic resins, olefine resins, vinyle resins, saturated polyester resins, polyamide resins, alkyd resins, epoxy resins, xylene resins, etc., together with, as desired, a charge control agent, a toner-blocking agent, etc. These resins are selected depending upon the order of the charging tendency thereof.
  • the pigments are made of, for example, carbon black when they are black, red iron oxide, cadmium red, fast red, etc., when they are red.
  • an oil-soluble dye such as nigrosine base (C.1.5045), oil black (C.1.26150), spirane blue, etc.; metal naphthenates; metallic fattiates soaps; resinate soaps; azo dyes containing metals; etc.
  • silica, alumina, talc, etc. can be used as the charge control agent.
  • any of magnetic carriers known to be useful for two-colored electrophotography may be used, which is made of particles such as ferrite, nickel, cobalt, iron or the like the surface of which is coated with a polymer resin to improve the control of the friction-charging characteristic and the humidity depending characteristic.

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

Claims (10)

1. Procédé électrophotographique pour élec- trophotographie en deux couleurs, consistant:
(1) à former une image latente électrostatique à polarités positive et négative sur un milieu de formation d'images latentes électrostatiques,
(2) à amener un agent de développement à un manchon non magnétique, cet agent de développement comprenant un premier toner couleur isolant et non magnétique chargé avec une polarité électrique donnée, un second toner couleur isolant et non magnétique chargé avec une polarité différente de le polarité du premier toner couleur et un support magnétique,
(3) à transférer le premier toner couleur du manchon à un premier rouleau de développement,
(4) à transférer le premier toner couleur de ce premier rouleau de développement à l'image latente électrostatique ayant une polarité différente de la polarité de la charge appliquée au premier toner couleur,
(5) à transférer le second toner couleur du manchon à un second rouleau de développement et
(6) à transférer le second toner couleur situé sur ce second rouleau de développement à l'image latente électrostatique ayant l'autre polarité.
2. Procédé électrophotographique pour élec- trophotographie en deux couleurs suivant la revendication 1, dans lequel l'image latente électrostatique est formée sur un photorécepteur.
3. Procédé électrophotographique pour élec- trophotographie en deux couleurs suivant la revendication 1 ou 2, selon lequel l'agent de développement est maintenu sur le manchon à l'aide d'un aimant fixe disposé à l'intèrieur de ce manchon.
4. Procédé électrophotographique pour élec- trophotographie en deux couleurs suivant la revendication 1, 2 ou 3, selon lequel un potentiel de polarisation présentant une polarité différente de la polarité du premier toner couleur est appliquée sur le premier rouleau de développement.
5. Procédé électrophotographique pour élec- trophotographie en deux couleurs suivant l'une quelconque des revendications précédentes, selon lequel un potentiel de polarisation offrant une polarité différente de la polarité du second toner couleur est appliqué au second rouleau de développement.
6. Appareil électrophotographique, comprenant:
(1) un milieu (1) sur lequel peut être formée une image latente électrostatique,
(2) des moyens permettant de former une image latente électrostatique à polarités positive et négative sur ce milieu (1),
(3) un manchon non magnétique (430),
(4) un réservoir d'agent de développement (42) contenant un premier toner couleur isolant et non magnétique (411) chargé suivant une polarité électrique donnée, un second toner couleur isolant et non magnétique (412) chargé avec une polarité différente de la polarité du premier toner couleur et un support magnétique (413),
(5) des moyens d'amenée permettant d'amener l'agent de développement au manchon non magnétique (430),
(6) des moyens magnétique (431) permettant de maintenir l'agent de développement sur ce manchon,
(7) un premier (44) et un second (45) rouleaux de développement, dont chacun est disposé entre le manchon (430) et le milieu (1) et (8) des moyens (440, 450) destinés à transférer le premier toner couleur du manchon (430) au premier rouleau de développement (44) et le second toner couleur au second rouleau de développement (45).
7. Appareil électrophotographique suivant la revendication 6, dans lequel ledit milieu (1) est un photorécepteur.
8. Appareil électrophotographique suivant la revendication 6 ou 7, comprenant en outre un aimant fixe (431) disposé à l'intérieur du manchon et permettant de maintenir l'agent de développement sur ce manchon.
9. Appareil électrophotographique suivant la revendication 6, 7 ou 8, comprenant des moyens (440) permettant d'appliquer au premier rouleau de développement (44) un potentiel de polarisation offrant une polarité différente de la polarité du premier toner couleur.
10. Appareil électrophotographique suivant l'une quelconque des revendications 6 à 9, comprenant des moyens (450) permettant d'appliquer au second rouleau de développement (45) un potentiel de polarisation offrant une polarité différente de la polarité du second toner couleur.
EP19850303870 1984-05-31 1985-05-31 Procédé de développement pour électrophotographie en deux couleurs et appareil de développement à cet effet Expired EP0166544B1 (fr)

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
JP112335/84 1984-05-31
JP59112335A JPS60256159A (ja) 1984-05-31 1984-05-31 ２色電子写真の現像方法およびその装置

Publications (2)

Publication Number Publication Date
EP0166544A1 EP0166544A1 (fr) 1986-01-02
EP0166544B1 true EP0166544B1 (fr) 1988-09-21

Family

ID=14584103

Family Applications (1)

Application Number Title Priority Date Filing Date
EP19850303870 Expired EP0166544B1 (fr) 1984-05-31 1985-05-31 Procédé de développement pour électrophotographie en deux couleurs et appareil de développement à cet effet

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EP (1) EP0166544B1 (fr)
JP (1) JPS60256159A (fr)
DE (1) DE3565184D1 (fr)

Families Citing this family (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
EP0322940A1 (fr) * 1987-12-07 1989-07-05 Agfa-Gevaert N.V. Développement à sec par agent de contraste en poudre
US5032872A (en) * 1989-10-30 1991-07-16 Xerox Corporation Developing device with dual donor rollers including electrically biased electrodes for each donor roller
US5010368A (en) * 1990-02-20 1991-04-23 Xerox Corporation Magnetic transport roll for supplying toner or carrier and toner to a donor and magnetic developer roll respectively
US5075185A (en) * 1990-03-28 1991-12-24 Xerox Corporation Imaging process comprising tri-level imaging area and an aluminum complex charge enhancing additive
US5047806A (en) * 1990-06-14 1991-09-10 Xerox Corporation Meterless single component development

Family Cites Families (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPS6028351B2 (ja) * 1977-10-13 1985-07-04 株式会社リコー ２色電子写真複写装置
JPS6032191B2 (ja) * 1978-05-24 1985-07-26 株式会社リコー 二色現像方法
US4351604A (en) * 1979-04-26 1982-09-28 Ricoh Company, Ltd. Multi-color electrostatic copying apparatus
DE3102960A1 (de) * 1980-01-30 1982-01-14 Ricoh Co., Ltd., Tokyo Kopierverfahren und kopiereinrichtung

Also Published As

Publication number Publication date
JPS60256159A (ja) 1985-12-17
EP0166544A1 (fr) 1986-01-02
DE3565184D1 (en) 1988-10-27

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