EP0000671A2 - Appareil électrophotographique et procédé utilisant des particules de vireur électrophotoconductrices - Google Patents

Appareil électrophotographique et procédé utilisant des particules de vireur électrophotoconductrices Download PDF

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Publication number
EP0000671A2
EP0000671A2 EP78300229A EP78300229A EP0000671A2 EP 0000671 A2 EP0000671 A2 EP 0000671A2 EP 78300229 A EP78300229 A EP 78300229A EP 78300229 A EP78300229 A EP 78300229A EP 0000671 A2 EP0000671 A2 EP 0000671A2
Authority
EP
European Patent Office
Prior art keywords
image
electrode
particles
toner particles
toner
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.)
Withdrawn
Application number
EP78300229A
Other languages
German (de)
English (en)
Other versions
EP0000671A3 (fr
Inventor
Clark Nelson Kurtz
Julian Cheng
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.)
Eastman Kodak Co
Original Assignee
Eastman Kodak Co
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 Eastman Kodak Co filed Critical Eastman Kodak Co
Publication of EP0000671A2 publication Critical patent/EP0000671A2/fr
Publication of EP0000671A3 publication Critical patent/EP0000671A3/fr
Withdrawn legal-status Critical Current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
    • G03G13/00—Electrographic processes using a charge pattern
    • G03G13/01—Electrographic processes using a charge pattern for multicoloured copies
    • G03G13/016—Electrographic processes using a charge pattern for multicoloured copies in which the colour powder image is formed directly on the recording material, e.g. DEP methods
    • 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
    • G03G15/22—Apparatus for electrographic processes using a charge pattern involving the combination of more than one step according to groups G03G13/02 - G03G13/20
    • G03G15/24—Apparatus for electrographic processes using a charge pattern involving the combination of more than one step according to groups G03G13/02 - G03G13/20 whereby at least two steps are performed simultaneously
    • 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
    • G03G15/22—Apparatus for electrographic processes using a charge pattern involving the combination of more than one step according to groups G03G13/02 - G03G13/20
    • G03G15/34—Apparatus for electrographic processes using a charge pattern involving the combination of more than one step according to groups G03G13/02 - G03G13/20 in which the powder image is formed directly on the recording material, e.g. by using a liquid toner
    • G03G15/344—Apparatus for electrographic processes using a charge pattern involving the combination of more than one step according to groups G03G13/02 - G03G13/20 in which the powder image is formed directly on the recording material, e.g. by using a liquid toner by selectively transferring the powder to the recording medium, e.g. by using a LED array
    • G—PHYSICS
    • G03—PHOTOGRAPHY; CINEMATOGRAPHY; ANALOGOUS TECHNIQUES USING WAVES OTHER THAN OPTICAL WAVES; ELECTROGRAPHY; HOLOGRAPHY
    • G03G—ELECTROGRAPHY; ELECTROPHOTOGRAPHY; MAGNETOGRAPHY
    • G03G9/00—Developers
    • G03G9/08—Developers with toner particles

Definitions

  • the present invention relates to electrophotography and, in particular, to improved electrophotographic methods and apparatus for producing images with electrophotosensitive toner.
  • multi-colored photoconductive toner particles are directed by an air blast through a screen grid and against a transparent conductive layer carried on a transparent plate which is spaced away, from and parallel to the screen grid.
  • the conductive layer and screen grid are maintained at a suitable potential difference by connection to a source of high voltage while a multi-color light image pattern is projected onto the transparent plate.
  • the appropriately colored toner particles are charged by their passage through the screen grid and adhere to the conductive layer forming a color image thereon.
  • Toner particles'which remain inactive because of their non-response to the wavelengths of the exposing light are drawn into ducts and returned to a receiving chamber for reuse.
  • the colored toner particles on the conductive layer are then transferred to a black paper or plastic base and fixed thereon by heat or other means.
  • the problem of producing images with high density, and lower levels of background deposition is solved by providing a method and apparatus wherein an electric field is provided across a layer of electrophotosensitive toner particles in powdered form and the particles within such field are exposed to a light image of an original to be reproduced characterized in that the toner particles are triboelectrically charged and moved by an applicator into contact at an image zone with successive portions of an oppositely charged image electrode while said particles are simultaneously exposed to corresponding successive portions of the light image of the original.
  • the toner particles are in mixture with magnetic carrier particles and a magnetic brush is utilized for applying the toner particles to the image electrode at the image zone.
  • a multicolor mixture of first, second and third colored toner particles which are primarily electrically photosensitive to light of first, second and third wavelength bands, respectively, is used in connection with a multicolor original to obtain a positive color reproduction.
  • the present invention relates to electrophotography and, in particular, to improved electrophotographic methods and apparatus for producing images with electrophotosensitive toner.
  • multi-colored photoconductive toner particles are directed by an air blast through a screen grid and against a transparent conductive layer carried on a transparent plate which is spaced away, from and parallel to the screen grid.
  • the conductive layer and screen grid are maintained at a suitable potential difference by connection to a source of high voltage while a multi-color light image pattern is projected onto the transparent plate.
  • the appropriately colored toner particles are charged by their passage through the screen grid and adhere to the conductive layer forming a color image thereon.
  • Toner particles-which remain inactive . because of their non-response to the wavelengths of the exposing light are drawn into ducts and returned to a receiving chamber for reuse.
  • the colored toner particles on the conductive layer are then transferred to a black paper or plastic base and fixed thereon by heat or other means.
  • the problem of producing images with high density, and lower levels of background deposition is solved by providing a method and apparatus wherein an electric field is provided across a layer of electrophotosensitive toner particles in powdered form and the particles within such field are exposed to a light image of an original to be reproduced characterized in that the toner particles are triboelectrically charged and moved by an applicator into contact at an image zone with successive portions of an oppositely charged image electrode while said particles are simulta- neausly exposed to corresponding successive portions of the light image of the original.
  • the toner particles are in mixture with magnetic carrier particles and a magnetic brush is utilized for applying the toner particles to the image electrode at the image zone.
  • a multicolor mixture of first, second and third colored toner particles which are primarily electrically photosensitive to light of first, second and third wavelength bands, respectively, is used in Connection with a multicolor original to obtain a positive color reproduction. modulate light in accordance with their image pattern; and the toner which has been moved proximate the opposite surface of the image electrode is exposed in accordance with these light patterns. Upon such exposure, the illuminated toner particles become conductive and lose, or reverse, their charge. Toner particles which are not subjected to light retain their triboelectric charge and are attracted to the oppositely biased surface of the image electrode, thus forming a positive image sense reproduction of the original on the contacted surface of the image electrode 2. The neutral or reversely charged toner particles are not attracted to the image electrode and are recirculated back into the reservoir for renewed triboelectric charging,
  • fur brush applicators of the type having animal or synthetic bristles, properly triboelectrically related to the toner can be used. It is desirable, however, that the brush/developer combination of any particular implementation of the present invention allow for a high field in the exposure station while also insuring that carrier particles themselves are not attracted to the image electrode.
  • electrically insulative carrier material Electrically insulative bristles on a fur brush applicator can be utilized.
  • an electrically insulative surface layer on the outer periphery of the transport drum such as shown in Fig. 1 can be utilized.
  • an electrically insulative layer could be provided on the surface of image electrode 2, so long as the attractive force provided behind it is sufficient to attract unexposed particles from their triboelectric bond with the applicator.
  • the developer mixture can comprise either a single type of colored electrophotosensitive toner particles or a mixture.of differently colored toner particle types.
  • the particles In the first instance it is necessary only that the particles be sensitive to one or more wavelength ranges over the panchromatic exposure source output.
  • each toner particle type it is desirable that each toner particle type have a sensitivity to a particular color light.
  • One desirable embodiment utilizes cyan, magenta and yellow toner particles which are sensitive substantialy only to red, green and blue light respectively.
  • Figs. 2a-2c schematically indicate the effects involved in creating a multicolor copy in accordance with the present invention using a toner mixture such as described above.
  • Figs. 2a and 2b indicate successive stages of cooperation between the applicator and image electrode, with the light color components which comprise different projected image portions indicated by arrows R, G and B (red, green and blue) directed at the zones of the image electrode through which such image portions are directed.
  • Fig. 2c illustrates the color of toner deposited on the image electrode at the zones illustrated in Figs. 2a and 2b, after cooperation with the applicator.
  • the amount of discharge of toner of a particular color is proportional to the intensity of light of its activating type. For example, high-intensity red light discharges or reverses the charge of a larger quantity of cyan particles than is discharged by low-intensity red-light image, which would allow a partial deposition of cyan toner particles present at the interface. Thus, a tone scale for all colors can be attained.
  • the toner image which continues to bear an electrostatic charge can be transferred readily to a copy sheet, e.g., plain paper, in known manner by moving portions of the copy sheet sequentially into transfer relation with portions of the image electrode, at a transfer station.
  • a copy sheet e.g., plain paper
  • Conventional electrophotographic transfer apparatus and techniques can be utilized, e.g., a corona charging device of polarity opposite the toner and magnitude greater than the bias on the image electrode.
  • the toner bearing copy sheet can then be moved past a conventional fusing station where the toner is fixed to the surface of the paper.
  • Radiant or roller fusers or other types of toner fixing devices used in electrography are suitable.
  • the image electrode is then cleaned of residual toner and ready for another image cycle. Cleaning can be performed by conventional techniques or by recycling the image electrode past the applicator with the bias field between applicator and image electrode reversed to drive the toner back to the brush.
  • an ultraviolet radiation sensitive photoconductor as the image electrode and provide the bias to that image electrode as a uniform electrostatic pre- ' charge on its imaged surface.
  • cleaning and elimination of residual charge would be facilitated by an ultraviolet exposure during cleaning.
  • Fig. 3 illustrates one embodiment of the present invention for continuous operation, i.e., repetitive cycling of the image electrode along an operative path for successive imaging and trans.fer of the same or different originals.
  • the "continuous" apparatus 50 comprises a cylindrical image member 51 which can be formed, e.g., of conductive glass.
  • a source of high voltage potential 52 provides a positive polarity bias for the drum, in effect at least during the portion of its cycle of rotation between applicator 53 and transfer station 54.
  • the cylinder 51 is mounted for rotation on its axis by means not shown, but which provide an access opening for projection of the original image, via lens 55 and mirror 56, at the exposure zone 58.
  • the image projected at station 58 is a flowing one, e.g., provided by scanning successive portions of an original moving past an object plane of lens 55.
  • Magnetic brush 60, at the applicator station 53 is of the type described with respect to Fig. 1 and is mounted for rotation in developer reservoir 61 to provide triboelectrically-charged toner at the image station 58 in the manner previously described.
  • the brush can be connected to ground electrically.
  • transfer station 54 Spaced downstream from the applicator station 53, along the operative path of the image member 51, is transfer station 54 which can comprise a conductive roller 70 coupled to a source of positive potential 72 of magnitude sufficient to attract toner from the image member 51 and onto copy sheet 71.
  • the operative path of the image member 51 then leads to a cleaning station 80 which can comprise, e.g., a soft brush 81 and vacuum source.
  • the present invention provides the following advantages to dry electrophotographic imaging systems using photoconductive toner particles.
  • the triboelectric charging of photoconductive toner particles provides a mechanism for delivering a large quantity of such particles to the imaging zone located between the applicator and the image electrode. This increases image density.
  • Another advantage of triboelectric charging is that it provides the toner particles with uniform potential of correct.polarity. This, of course, is necessary to obtain proper control of the particle migration.
  • triboelectric charging of the toner particles in combination with the exposure of such toner particles to successive portions of the light image is believed to aid in restricting the random motion of the toner particles during their migration from the applicator to the image electrode. This improves the level of particle deposition in the background image areas.
  • a magnetic brush was located in an image arrangement as shown in Fig. 1.
  • the developer mixture comprised 500 grams of Xerox brand 5R54 carrier beads and 6 grams of photoconductive toner particles comprised of:
  • the toner developed a negative triboelectric charge.
  • a Nesatron plate was used as the transparent electrode and a Kodak Carousel 110 size slide projector, spaced seven (7) inches from the plate, was used to project a transparency image co-moving with the transparent electrode. Voltages in the range of 900-1500 volts were provided between the brush and plate (plate positivel. Positive images were formed on the transparent electrode as it passed over the rotating magnetic brush. These images could be completely erased by passing the plate back over the brush with a negative voltage applied to the plate.
  • Example 2 a 10- micron layer of Lexan 145 polymer, supported on conductive, nickelized plastic film, was mounted against a glass plate bearing an image, and an image was formed as in Example 1, using a voltage of 1350. volts (plate positive).
  • This example demonstrates that the toner may lose or reverse charge by interaction with the brush or carrier, because the insulative coating of Lexan polymer prevented intimate contact of the toner particles with a metallized electrode.
  • Particles composed of 60% Watchung Red B pigment (E. I. duPont deNemours & Co.), 20% 2,4,7-trinitrofluore- none, 10% Lexan 145 polymer and 10% PVT were mixed with carrier (Xerox 5R54) in the ratio of 6 g. toner to 500 g. carrier. Good positive images were obtained on Nesatron plates (biased positive) at 1100V. A grey scale was obtained.
  • Composite particles consisting of 50% Cyan Blue GTNF pigment and 50% poly[4-di-p-tolylamino)styrene] were added to IBM Brand carrier (sold for IBM II copiers) in the ratio of 5g. toner to 500 g. carrier. Images were obtained at 1KV on the image electrode. Toning was excellent, indicative of a high triboelectric charge level (particles positively chargedl.
  • the aforedescribed apparatus can be used industrially as a document copier.

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  • Physics & Mathematics (AREA)
  • General Physics & Mathematics (AREA)
  • Dry Development In Electrophotography (AREA)
  • Electrophotography Using Other Than Carlson'S Method (AREA)
  • Developing Agents For Electrophotography (AREA)
EP78300229A 1977-08-01 1978-08-01 Appareil électrophotographique et procédé utilisant des particules de vireur électrophotoconductrices Withdrawn EP0000671A3 (fr)

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
US82096077A 1977-08-01 1977-08-01
US820960 1977-08-01

Publications (2)

Publication Number Publication Date
EP0000671A2 true EP0000671A2 (fr) 1979-02-07
EP0000671A3 EP0000671A3 (fr) 1979-02-21

Family

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Family Applications (1)

Application Number Title Priority Date Filing Date
EP78300229A Withdrawn EP0000671A3 (fr) 1977-08-01 1978-08-01 Appareil électrophotographique et procédé utilisant des particules de vireur électrophotoconductrices

Country Status (2)

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EP (1) EP0000671A3 (fr)
JP (1) JPS5434835A (fr)

Cited By (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
GB2223604A (en) * 1988-09-06 1990-04-11 Mitsubishi Electric Corp Colour printer
EP0672969A2 (fr) * 1994-03-18 1995-09-20 Hitachi, Ltd. Méthode et appareil de formation d'image

Citations (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3100426A (en) * 1960-04-26 1963-08-13 Edward K Kaprelian Electrophotographic printers
GB950297A (en) * 1960-08-09 1964-02-26 Wilhelm Uhrig Electrostatic photocopying
DE1907903A1 (de) * 1968-02-23 1969-09-18 Xerox Corp Elektrophoretisches Abbildungsverfahren und Vorrichtung zur Durchfuehrung des Verfahrens
DE1910068B2 (de) * 1968-02-29 1972-07-27 Eastman Kodak Co., Rochester, N.Y. (V.StA.) Verfahren und vorrichtung zum entwickeln eines auf einem aufzeichnungsmaterial befindlichen ladungsbildes
US3703335A (en) * 1969-12-22 1972-11-21 Xerox Corp Multiple exposure imaging apparatus
DE2055993B2 (de) * 1969-11-14 1977-04-21 Xerox Corp., Rochester, N.Y. (V.St.A.) Vorrichtung zum reinigen eines mit einem uebertragbaren medium verschmutzten umlaufenden aufzeichnungstraegers

Patent Citations (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3100426A (en) * 1960-04-26 1963-08-13 Edward K Kaprelian Electrophotographic printers
GB950297A (en) * 1960-08-09 1964-02-26 Wilhelm Uhrig Electrostatic photocopying
DE1907903A1 (de) * 1968-02-23 1969-09-18 Xerox Corp Elektrophoretisches Abbildungsverfahren und Vorrichtung zur Durchfuehrung des Verfahrens
DE1910068B2 (de) * 1968-02-29 1972-07-27 Eastman Kodak Co., Rochester, N.Y. (V.StA.) Verfahren und vorrichtung zum entwickeln eines auf einem aufzeichnungsmaterial befindlichen ladungsbildes
DE2055993B2 (de) * 1969-11-14 1977-04-21 Xerox Corp., Rochester, N.Y. (V.St.A.) Vorrichtung zum reinigen eines mit einem uebertragbaren medium verschmutzten umlaufenden aufzeichnungstraegers
US3703335A (en) * 1969-12-22 1972-11-21 Xerox Corp Multiple exposure imaging apparatus

Non-Patent Citations (1)

* Cited by examiner, † Cited by third party
Title
R.M. SCHAFFERT: "ELECTROPHOTOGRAPHY", 1965, FOCAL PRESS, London and New York, page 80 to 81 *

Cited By (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
GB2223604A (en) * 1988-09-06 1990-04-11 Mitsubishi Electric Corp Colour printer
GB2223604B (en) * 1988-09-06 1992-08-19 Mitsubishi Electric Corp Printer
EP0672969A2 (fr) * 1994-03-18 1995-09-20 Hitachi, Ltd. Méthode et appareil de formation d'image
EP0672969A3 (fr) * 1994-03-18 1996-08-07 Hitachi Ltd Méthode et appareil de formation d'image.

Also Published As

Publication number Publication date
EP0000671A3 (fr) 1979-02-21
JPS5434835A (en) 1979-03-14

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Inventor name: KURTZ, CLARK NELSON