WO1992017825A1 - Systeme d'imagerie muni d'elements de transfert intermediaires - Google Patents

Systeme d'imagerie muni d'elements de transfert intermediaires Download PDF

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Publication number
WO1992017825A1
WO1992017825A1 PCT/NL1991/000050 NL9100050W WO9217825A1 WO 1992017825 A1 WO1992017825 A1 WO 1992017825A1 NL 9100050 W NL9100050 W NL 9100050W WO 9217825 A1 WO9217825 A1 WO 9217825A1
Authority
WO
WIPO (PCT)
Prior art keywords
intermediate transfer
transfer member
image
imaging apparatus
toner
Prior art date
Application number
PCT/NL1991/000050
Other languages
English (en)
Inventor
Benzion Landa
Original Assignee
Spectrum Sciences B.V.
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
Priority claimed from CA002075948A external-priority patent/CA2075948C/fr
Application filed by Spectrum Sciences B.V. filed Critical Spectrum Sciences B.V.
Priority to JP3507718A priority Critical patent/JPH06508444A/ja
Priority to EP91907895A priority patent/EP0577597B1/fr
Priority to US08/119,203 priority patent/US5410392A/en
Priority to DE69119612T priority patent/DE69119612T2/de
Priority to PCT/NL1991/000050 priority patent/WO1992017825A1/fr
Publication of WO1992017825A1 publication Critical patent/WO1992017825A1/fr
Priority to HK199296A priority patent/HK199296A/xx

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Classifications

    • G—PHYSICS
    • G03—PHOTOGRAPHY; CINEMATOGRAPHY; ANALOGOUS TECHNIQUES USING WAVES OTHER THAN OPTICAL WAVES; ELECTROGRAPHY; HOLOGRAPHY
    • G03G—ELECTROGRAPHY; ELECTROPHOTOGRAPHY; MAGNETOGRAPHY
    • G03G5/00—Recording members for original recording by exposure, e.g. to light, to heat, to electrons; Manufacture thereof; Selection of materials therefor
    • G03G5/02—Charge-receiving layers
    • G03G5/04—Photoconductive layers; Charge-generation layers or charge-transporting layers; Additives therefor; Binders therefor
    • 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
    • G03G15/0142—Structure of complete machines
    • G03G15/0147—Structure of complete machines using a single reusable electrographic recording member
    • G03G15/0152—Structure of complete machines using a single reusable electrographic recording member onto which the monocolour toner images are superposed before common transfer from the recording member
    • G03G15/0173—Structure of complete machines using a single reusable electrographic recording member onto which the monocolour toner images are superposed before common transfer from the recording member plural rotations of recording member to produce multicoloured copy, e.g. rotating set of developing units
    • 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
    • G03G15/14—Apparatus for electrographic processes using a charge pattern for transferring a pattern to a second base
    • G03G15/16—Apparatus for electrographic processes using a charge pattern for transferring a pattern to a second base of a toner pattern, e.g. a powder pattern, e.g. magnetic transfer
    • G03G15/1605—Apparatus for electrographic processes using a charge pattern for transferring a pattern to a second base of a toner pattern, e.g. a powder pattern, e.g. magnetic transfer using at least one intermediate support
    • G03G15/161—Apparatus for electrographic processes using a charge pattern for transferring a pattern to a second base of a toner pattern, e.g. a powder pattern, e.g. magnetic transfer using at least one intermediate support with means for handling the intermediate support, e.g. heating, cleaning, coating with a transfer agent
    • 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
    • G03G15/23—Apparatus for electrographic processes using a charge pattern involving the combination of more than one step according to groups G03G13/02 - G03G13/20 specially adapted for copying both sides of an original or for copying on both sides of a recording or image-receiving material
    • G03G15/231—Arrangements for copying on both sides of a recording or image-receiving material
    • G03G15/232—Arrangements for copying on both sides of a recording or image-receiving material using a single reusable electrographic recording member
    • 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
    • G03G15/23—Apparatus for electrographic processes using a charge pattern involving the combination of more than one step according to groups G03G13/02 - G03G13/20 specially adapted for copying both sides of an original or for copying on both sides of a recording or image-receiving material
    • G03G15/231—Arrangements for copying on both sides of a recording or image-receiving material
    • G03G15/238—Arrangements for copying on both sides of a recording or image-receiving material using more than one reusable electrographic recording member, e.g. single pass duplex copiers
    • G—PHYSICS
    • G03—PHOTOGRAPHY; CINEMATOGRAPHY; ANALOGOUS TECHNIQUES USING WAVES OTHER THAN OPTICAL WAVES; ELECTROGRAPHY; HOLOGRAPHY
    • G03G—ELECTROGRAPHY; ELECTROPHOTOGRAPHY; MAGNETOGRAPHY
    • G03G7/00—Selection of materials for use in image-receiving members, i.e. for reversal by physical contact; Manufacture thereof
    • 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
    • G03G2215/01—Apparatus for electrophotographic processes for producing multicoloured copies
    • G03G2215/0167—Apparatus for electrophotographic processes for producing multicoloured copies single electrographic recording member
    • G03G2215/0174—Apparatus for electrophotographic processes for producing multicoloured copies single electrographic recording member plural rotations of recording member to produce multicoloured copy
    • 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
    • G03G2215/0626—Developer liquid type (at developing position)
    • 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
    • G03G2215/16—Transferring device, details
    • G03G2215/1666—Preconditioning of copy medium before the transfer point
    • G03G2215/1671—Preheating the copy medium before the transfer point
    • 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
    • G03G2215/16—Transferring device, details
    • G03G2215/1676—Simultaneous toner image transfer and fixing
    • G03G2215/1695—Simultaneous toner image transfer and fixing at the second or higher order transfer point

Definitions

  • the present invention relates to image transfer techniques and apparatus for use in electrophotography.
  • BACKGROUND OF THE INVENTION Various prior publications deal with the transfer of single and multiple powder and liquid toner images from a photoreceptor on which they are formed to an intermediate transfer member for subsequent transfer to a final substrate.
  • U. S. Patent 3,838,919 to Takahashi describes a powder toner system in which color toner images are sequentially formed on an image forming member, individually transferred to an intermediate transfer member and transferred at one time to a recording member.
  • U. S. Patent 4,518,976 to Tarumi et al. describes a monochrome powder toner system in which a powder image is developed on a photoreceptor, and transferred electrostatically to an intermediate transfer member. Downstream this transfer, the intermediate transfer member and the image thereon are heated before transfer to a preheated substrate.
  • U. S. Patent 4,515,460 to Knechtel describes a powder toner apparatus wherein separate toner images are sequentially developed on a photoreceptor and electrostatically transferred to an intermediate transfer member. After all of the individual images have been transferred to the intermediate transfer member, they are transferred electrostatically to the final substrate.
  • U. S. Patent 4,585,319 to Oka oto et al. describes a powder developer type, single color system, utilizing a temperature controlled photoreceptor, a heated intermediate transfer member and a heated transfer fixing roller which is heated to a temperature slightly higher than that of the intermediate transfer member.
  • U. S. Patent 4,690,539 to Radulski et al. describes a liquid toner multi-color system in which a color image is developed on a photoreceptor and transferred to a belt type intermediate transfer member. The liquid carrier is removed from the toner image on the belt. There is no mention of heating the intermediate transfer member or of the problem of back transfer.
  • U. S. Patent 4,585,319 to Oka oto et al. describes a powder developer type, single color system, utilizing a temperature controlled photoreceptor, a heated intermediate transfer member and a heated transfer fixing roller which is heated to a temperature slightly higher than that of the intermediate transfer member.
  • Patent 4,708,460 to Langdon describes a single color liquid toner system in which a developed image is transferred from a photoreceptor to an intermediate transfer member, heated on the transfer member and then transferred to a final substrate.
  • U. S. Patent 3,847,478 to Young describes a duplex printing system, wherein a developed image is transferred from a photoconductor to an intermediate transfer member, a second image is developed on the photoconductor and both images are transferred electrostatically to opposite sides of a piece of paper passed between the intermediate transfer member and the photoreceptor.
  • imaging apparatus for printing an image on a substrate from a latent image formed on a latent image bearing surface including developing apparatus for developing the latent image with toner, preferably with liquid toner having carrier liquid and toner particles, to form a developed toner image of a given size, a first intermediate transfer member, preferably having a cylindrical shape and having a surface area large enough to accommodate the developed toner image, first transfer apparatus for transferring the developed toner image from the latent image bearing surface to the first intermediate transfer member, a second intermediate transfer member, preferably a cylindrical shape having a surface area smaller than the surface area of the first intermediate transfer member and second transfer apparatus for transferring of the developed image from the first intermediate transfer member to the second intermediate transfer member and from the second intermediate transfer member to the substrate.
  • the imaging apparatus includes heating apparatus for heating the first intermediate transfer member to a first temperature and for heating the second intermediate transfer member to a second temperature higher than the first temperature.
  • the second transfer apparatus includes apparatus for heating the substrate, preferably including a heating backing roller operative to apply heat and pressure to the image during image transfer to the substrate.
  • the imaging apparatus also includes first voltage apparatus for maintaining the first intermediate transfer member at a first voltage.
  • at least a portion of the latent image bearing surface is at a second voltage and the first voltage is different from the second voltage.
  • the imaging apparatus also includes second voltage means for maintaining the second intermediate transfer member at a third voltage.
  • the second intermediate transfer member has a diameter of less than about 40 mm, more preferably a diameter of less than about 30 mm.
  • transfer of the developed image from the second intermediate transfer member to the substrate commences before transfer of the developed image from the first intermediate transfer member to the second transfer member is complete.
  • the imaging apparatus includes means for producing a plurality of developed images on the image bearing surface and for transferring the plurality of developed images to the first transfer member in mutual alignment thereon.
  • FIG. 1 is a simplified sectional illustration of electrophotographic apparatus constructed and operative in accordance with a preferred embodiment of the present invention
  • Fig. 2 is a simplified sectional illustration of electrophotographic apparatus constructed and operative in accordance with another preferred embodiment of the present invention
  • Fig. 3A is a simplified sectional illustration of elec- trophotographic apparatus constructed and operative in ac- cordance with yet another preferred embodiment of the present invention
  • Fig. 3B is a simplified sectional illustration of elec- trophotographic apparatus constructed and operative in ac- cordance with yet another preferred embodiment of the present invention
  • Fig. 4 is a simplified sectional illustration of a elec- trophotographic apparatus constructed and operative in ac- cordance with yet another preferred embodiment of the present invention
  • Fig. 3A is a simplified sectional illustration of elec- trophotographic apparatus constructed and operative in ac- cordance with yet another preferred embodiment of the present invention
  • Fig. 3B is a simplified sectional illustration of ele
  • FIG. 5 is a simplified sectional illustration of electrophotographic apparatus constructed and operative in accordance with yet another preferred embodiment of the present invention
  • Fig. 6 is a simplified sectional illustration of electrophotographic apparatus constructed and operative in accordance with yet another preferred embodiment of the present invention
  • Fig. 7 is a graphical illustration of the temperature variation along a low thermal mass intermediate transfer member in an arrangement such as that illustrated in Fig. 6.
  • DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS Reference is now made to Fig. 1 which illustrates electrophotographic imaging apparatus constructed and operative in accordance with a preferred embodiment of the present invention. This and other embodiments of the invention are described in the context of liquid developer systems with negatively charged toner particles and positively charged photoreceptors.
  • Such systems operate in a "write-white” mode, for which areas which are not to be toned are exposed to light.
  • the invention may be useful for other combinations of toner charge, photoreceptor charge as well as for other writing systems, such as "write-black” systems.
  • the apparatus of the invention is described using a liquid developer system.
  • the liquid developer of Example 1 of U. S. Patent 4,794,651 can be used, but other suitable developers may be used in the practice of the invention.
  • liquid developers comprising toner particles which solvate the carrier liquid of the developer at elevated temperatures, above room temperature.
  • the apparatus of Fig. 1 comprises a drum 10 arranged for rotation about an axle 12 in a direction generally indicated by arrow 14.
  • Drum 10 is formed with a cylindrical photoreceptor surface 16.
  • a corona discharge device 18 is operative to generally uniformly charge photoreceptor surface 16 with a positive charge.
  • An exposure unit including a lens 20 Lens 20, focuses a desired image, which may be laser generated, onto charged photoreceptor surface 16, selectively discharging the photoreceptor surface, thus producing an electrostatic latent image thereon.
  • a desired image which may be laser generated
  • a desired image which may be laser generated
  • the development unit 22 can, for example, comprise a plurality of developers, one for each color, which are selectively engaged with the photoreceptor, as described, for example, in U.S. Patent 4,690,539, which is incorporated herein by reference, or a single development station where the liquid toner is changed between colors, or any other suitable development system.- In general this development process takes place at a relatively low temperature, namely approximately the temperature of the environment of the system. In accordance with a preferred embodime t of the invention, following application of toner thereto, photoreceptor surface 16 passes a typically positively charged rotating roller 26, preferably rotating in a direction indicated by an arrow 28.
  • Roller 26 functions as a metering roller and reduces the thickness of liquid on photoreceptor surface 16. Typically the spatial separation of roller 26 from photoreceptor surface 16 is about 50 microns.
  • the- voltage on roller 26 is intermediate the voltages of the latent image areas and of the background areas on the photoreceptor surface. Typical voltages are: roller 26: +200V, background area: +50V and latent image 1 areas: up to about +1000V.
  • Rigidizing roller 30 is preferably
  • roller 30 is preferably resiliently urged against
  • roller 30 14 cally biased squeegee roller is used as roller 30.
  • Roller 30 14 cally biased squeegee roller is used as roller 30.
  • transfer member 40 is operative for receiving the toner image
  • This station may be any conventional cleaning station, comprising a cleaning roller 50 which may comprise a suitable resilient material such as foam polyethylene or neoprene.
  • Cleaning roller 50 may be wetted by clean lubricating cleaning liquid, which preferably comprises liquid developer from which all or nearly all of the toner particles have been removed.
  • Cleaning roller 50 is driven so that its surface moves opposite to surface 16 at their nip, to provide scrubbing action for removal of residual particles and carrier liquid from photoreceptor surface 16.
  • a scraper 56 completes the removal of any residual toner which may not have been removed by cleaning station 49.
  • a lamp 58 completes the cycle by removing any residual charge, characteristic of the previous image, from semiconductor surface 16.
  • Transfer of the image to intermediate transfer member 40 is preferably aided by providing electrification of intermediate transfer member 40 to a voltage opposite that of the charged particles, thereby causing transfer by electrophoresis. It has been found by the inventors, that, at least for the preferred developer, raising the temperature of the developed toner image to a temperature higher than the development temperature and room temperature aids this first transfer, even when the transfer is by electrophoresis. Subsequent final transfer of the image from intermediate transfer member 40 to substrate 42 is preferably aided by heat and pressure. A higher temperature than that used for first transfer is preferably utilized for this subsequent final transfer, in accordance with the present invention. In the prior art a liquid toner image was first transferred to an intermediate transfer member.
  • the toner image was heated during the interval between first and second transfer so as to aid in final transfer.
  • the preferred first transfer step i.e., the transfer of the liquid toner image to the intermediate transfer member includes the heating of the image either before or during first transfer.
  • the preferred 1 final transfer step i.e., the transfer of the liquid toner
  • the image is heated to a temperature at
  • photoreceptor 16 is at a first
  • some of the embodiments 1 can be characterized in that, when a toner image is
  • the composite, multicolor toner image is
  • One embodiment of the invention can be characterized in
  • intermediate transfer member 40 8 is heated to a temperature sufficient to enhance the 9 electrophoretic transfer of toner particles from 0 photoreceptor surface 16 to intermediate transfer member 40.
  • the invention is particularly useful in a multicolor system
  • Fig. 2 shows a second embodiment of the invention in
  • a third embodiment of the apparatus of the invention is
  • second intermediate transfer member 47 is 6 electrified to a second voltage, different from the first 7 voltage, to enhance transfer of the image thereto from 8 intermediate transfer member 40.
  • Transfer to second intermediate transfer member 47 can 0 occur sequentially for each of the images, or preferably the 1 images are collected on first intermediate transfer member 40 2 and then the multicolor image is transferred as a whole to 3 second intermediate transfer member 47 for final transfer to 4 the final substrate 42.
  • Fig. 3B Another embodiment of the apparatus of the invention is 6 shown in Fig. 3B which is identical to the embodiment shown 7 in Fig. 3A except that second intermediate transfer member 47 8 has a smaller diameter and in consequence has less surface area.
  • second intermediate transfer member 47 cannot hold at any one moment in time the complete latent image which is being transferred from first intermediate transfer member 41.
  • all the mulitcolor images are first collected on the first intermediate transfer member and only thereafter is the composite image transferred to the second intermediate transfer member.
  • the latent image is transferred from the second intermediate transfer member to final substrate 42 virtually simultaneously as it is being transferred to second intermediate transfer member 47 from first intermediate transfer member 41. The inventors have discovered that this configuration results in an enhancement of the quality of the image produced on the final substrate when compared with a configuration in which the second intermediate transfer member is full-sized.
  • the final substrate tends to adhere to the surface of the second intermediate transfer member as the image is being transferred, thereby causing a certain blurring of the image on the final substrate.
  • the second intermediate transfer member has a relatively small diameter, preferably less than 40 mm and more preferably less than 30 mm, the separation of the final substrate from the transfer member is improved, there is less tendency to adhesion, and the quality of the image on the final substrate is thereby enhanced.
  • first intermediate transfer member has a diameter of 70 mm or more, as required to hold an A4 sized image, or a 100 mm diameter or more, as required to hold an A3 sized image
  • optimal results will be obtained when intermediate transfer member 47 has a diameter of less than about 40 mm or less, preferably about 30 mm or less.
  • a duplex embodiment of the invention, for printing two sides of a substrate at the same time is shown in Fig. 4.
  • the separate color images which make up the multi- colored image to be printed on a first side of substrate 42 are first transferred sequentially to intermediate transfer member 40 and then are transferred, preferably as a group, to second intermediate transfer member 47.
  • Second image transfer member 47 is preferably heated to a higher temperature than intermediate transfer member 40.
  • intermediate transfer member 40 which is meanwhile kept out of transfer engagement with second intermediate transfer member 47.
  • Final substrate 42 is then passed between intermediate transfer member 40 and second intermediate transfer member 47, while pressing the two intermediate transfer members together to effect transfer of the images to both sides of the paper by heat and pressure.
  • second intermediate transfer member 47 heats substrate 42 and the image to a suitable temperature to assure good transfer of the image on intermediate transfer member 40 to substrate 42.
  • the paper may be heated before transfer as described above in connection with Fig. 2.
  • intermediate transfer member 40 acts to heat the image to a first temperature during first transfer from photoreceptor 16 to intermediate transfer member 40, and to heat the image to a second higher temperature before second and final transfer from intermediate transfer member 40 to final substrate 42.
  • Exemplary embodiments include the apparatus shown in Fig. 5. This apparatus is generally the same as the apparatus of Fig. 1, except that a cooling station 60 is operatively associated with intermediate transfer member 40 just before it returns to make contact with photoreceptor surface 16. Intermediate transfer member 40 is cooled at cooling station 60 to locally reduce the temperature of intermediate transfer member 40 before and during contact with the image on the photoreceptor.
  • Cooling station 60 may comprise, for example, apparatus 1 for providing a stream of cool air to the surface of the
  • 14 member 140 is of low heat capacity, and is heated only after
  • Colored liquid developer is prepared in the following
  • the heating unit being set at 130°C.
  • Preparation of Colored Developer 10 parts by weight of Elvax 5720 (E. I. Du Pont) and 5 parts by weight of Isopar L are mixed at low speed in a jacketed double planetary mixer connected to an oil heating unit for one hour, the heating unit being set at 130°C.
  • Pre-heated Isopar L is then added to reduce the solids concentration to preferably 35% and mixing is continued at high speed for one hour.
  • the heating unit is then disconnected and mixing is continued until the temperature of the mixture drops to 40°C.
  • the mixture is then transferred to an S-l attritor device equippe with 3/16 inch carbon steel media and pigment is added to the material in the attritor.
  • the mixture is diluted with Isopar L to about a 12-16% solids ratio, depending on the viscosity of the material and is ground without cooling until the temperature rises to about 60°C. Cooling, which reduces the temperature to about 30°C, is then commenced and grinding is continued for a total of 24 hours.
  • the mixture is removed from the device and diluted with Isopar L to 1.5% by weight solids concentration.
  • the particles in the resultant toner concentrate had an average diameter of 2.5 microns.
  • Charge director as known in the art, is added to give the final liquid developer. In a preferred embodiment of the invention the charge director of Example 1 the above referenced PCT publication WO 90/14617 is added to give the final liquid developer.
  • Appropriate colored pigments known in the art of liquid developer manufacture for example the list given in U. S. Patent 4,794,561 can be used.
  • Other suitable pigments are Sico Fast Yellow D1350 (BASF) , Lithol Rubin D4576 (BASF) , Lyonol Blue FG7351 (TOYO) and Lyonol Yellow 7G1310 (TOYO) . in amounts and combinations depending on the color and intensity required.
  • Aluminum Stearate can be added in small amounts.
  • other grinding media such as zirconia may be used.
  • Photoreceptor surface 16 is preferably formed of selenium.
  • Intermediate transfer member 40 is preferably formed of a cylindrical aluminum core coated with a 1 mm thick layer of very soft polyurethane having a hardness of 20-25 Shore A. This layer is covered by an offset printing blanket, preferably a KYNIO AIRTACK offset blanket, which is much harder than the polyurethane.
  • a thin conducting layer of conducting acrylic covers this layer and is covered in turn by a 0.1 mm layer of polyurethane of shore A Hardness 20. This layer is overcoated by a thin layer of Syl-Off type 291 or 294 silicone release coating. Liquid developer prepared in accordance with the method described above is used in the equipment of Fig. 1.
  • the temperature of the intermediate transfer layer should be less than about 50° C. For temperatures greater than about 50 degrees, there is a tendency for the previously transferred colors to back transfer to photoreceptor surface 16. Heating intermediate transfer member 40 improves image transfer to intermediate transfer member 40. Intermediate transfer member 40 is preferably heated to a temperature somewhat below that at which back transfer begins to occur. It is believed that the improvement in first transfer when the intermediate transfer member is heated may be a consequence of partial solvation of carrier liquid by the pigmented toner particles in the image.
  • One characteristic of the liquid developers preferred in the practice of this invention is that the pigmented toner particles contained therein ⁇ olvate the carrier liquid at elevated temperatures.
  • the paper should be at a temperature of at least about 70° C. Higher temperatures such as 80 or 90°can also be used, but substantially lower temperatures do not tackify the image enough to assure complete transfer from intermediate transfer member 40 to paper 42.
  • the precise temperatures used for particular configurations and combinations are a function of the material properties of the toner particles and the carrier liquid as well as of the quality of the release layer on the intermediate transfer member. Back transfer occurs due to the tackiness of the image, but is also influenced by the relative adhesion of the image to the release layer on the intermediate transfer member and to the photoreceptor.
  • the intermediate transfer member is heated to a surface temperature of 100°C and the paper is not heated. Calculations show that the image is at a temperature of 52 ⁇ C to 63°C during first transfer. During the interval between first and second transfer the image temperature rises to the intermediate transfer member's temperature of 100° C, and the image is cooled during second, final transfer to paper to a temperature of 73°C to 78°C.
  • the intermediate transfer member is heated to 50° C and backing roller 43 is heated to 120° C.
  • the image temperature on first transfer is approximately 43° C and on second transfer it is 75 ⁇ C to 78 ⁇ C.
  • the temperatures shown in figure 7 are also representative of values suitable for single image transfer.
  • the first transfer temperature must be low enough to assure that no back transfer takes place.

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  • Physics & Mathematics (AREA)
  • General Physics & Mathematics (AREA)
  • Electrostatic Charge, Transfer And Separation In Electrography (AREA)

Abstract

Un appareil d'imagerie permettant d'imprimer une image sur un substrat (42) à partir d'une image latente formée sur une surface support d'image latente (16), comprend un appareil de développement (22) pour développer l'image latente avec du toner pour produire une image développée au toner ayant des dimensions prédéterminées; un premier élément de transfert intermédiaire (40) présentant une superficie sufisamment grande pour recevoir l'image développée au toner; un premier moyen de transfert permettant de transférer l'image développée au toner depuis la surface support (16) d'image latente au premier élément de transfer intermédiaire (40); un deuxième élément de transfert intermédiaire (47) dont la superficie est inférieure à celle du premier élément de transfert intermédiaire (40), et un deuxième élément de transfert pour transférer ladite image développée depuis ledit premier élément de transfert intermédiaire (40) au deuxième élément de transfert intermédiaire (47) et depuis ledit élément de transfert intermédiaire (47) audit substrat (42). De préférence, le deuxième moyen de transfert intermédiaire (47) est un cylindre dont le diamètre est inférieur à 30 ou 40 mm.
PCT/NL1991/000050 1989-01-04 1991-03-26 Systeme d'imagerie muni d'elements de transfert intermediaires WO1992017825A1 (fr)

Priority Applications (6)

Application Number Priority Date Filing Date Title
JP3507718A JPH06508444A (ja) 1991-03-26 1991-03-26 中間転写部材を備えた像形成装置
EP91907895A EP0577597B1 (fr) 1991-03-26 1991-03-26 Systeme d'imagerie muni d'elements de transfert intermediaires
US08/119,203 US5410392A (en) 1991-03-26 1991-03-26 Imaging system with intermediate transfer members
DE69119612T DE69119612T2 (de) 1991-03-26 1991-03-26 Bilderzeugungsystem mit einem zwischenubertragungselement
PCT/NL1991/000050 WO1992017825A1 (fr) 1989-01-04 1991-03-26 Systeme d'imagerie muni d'elements de transfert intermediaires
HK199296A HK199296A (en) 1991-03-26 1996-10-31 Imaging system with intermediate transfer members

Applications Claiming Priority (4)

Application Number Priority Date Filing Date Title
US29345689A 1989-01-04 1989-01-04
US44687789A 1989-12-06 1989-12-06
CA002075948A CA2075948C (fr) 1989-01-04 1990-12-13 Systeme d'imagerie a element de transfert intermediaire
PCT/NL1991/000050 WO1992017825A1 (fr) 1989-01-04 1991-03-26 Systeme d'imagerie muni d'elements de transfert intermediaires

Publications (1)

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WO1992017825A1 true WO1992017825A1 (fr) 1992-10-15

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Cited By (7)

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US6785501B2 (en) 2001-04-03 2004-08-31 Pfu Limited Transfer-and-fixation system with preheated printing medium for creating images using liquid-development electrophotographic apparatus
US7005225B2 (en) 2002-11-12 2006-02-28 Samsung Electronics Company Organosol including amphipathic copolymeric binder having crystalline material, and use of the organosol to make dry tones for electrographic applications
US7014973B2 (en) 2002-11-12 2006-03-21 Samsung Electronics Company Organosol including amphipathic copolymeric binder made with Soluble High Tg Monomer and liquid toners for electrophotographic applications
US7052816B2 (en) 2003-01-03 2006-05-30 Samsung Electronics Company Organosol liquid toner including amphipathic copolymeric binder having crosslinkable functionality
US7074537B2 (en) 2002-11-12 2006-07-11 Samsung Electronics Company Organosol liquid toner including amphipathic copolymeric binder having crystalline component
US7135264B2 (en) 2002-11-12 2006-11-14 Samsung Electronics Company Organosol including amphipathic copolymeric binder and use of the organosol to make dry toners for electrographic applications
US7166405B2 (en) 2002-11-12 2007-01-23 Samsung Electronics Company Organosol including high Tg amphipathic copolymeric binder and liquid toners for electrophotographic applications

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WO1990004216A1 (fr) * 1988-10-04 1990-04-19 Spectrum Sciences B.V. Procede et appareil d'imagerie au moyen d'un element de transfert intermediaire

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Cited By (7)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US6785501B2 (en) 2001-04-03 2004-08-31 Pfu Limited Transfer-and-fixation system with preheated printing medium for creating images using liquid-development electrophotographic apparatus
US7005225B2 (en) 2002-11-12 2006-02-28 Samsung Electronics Company Organosol including amphipathic copolymeric binder having crystalline material, and use of the organosol to make dry tones for electrographic applications
US7014973B2 (en) 2002-11-12 2006-03-21 Samsung Electronics Company Organosol including amphipathic copolymeric binder made with Soluble High Tg Monomer and liquid toners for electrophotographic applications
US7074537B2 (en) 2002-11-12 2006-07-11 Samsung Electronics Company Organosol liquid toner including amphipathic copolymeric binder having crystalline component
US7135264B2 (en) 2002-11-12 2006-11-14 Samsung Electronics Company Organosol including amphipathic copolymeric binder and use of the organosol to make dry toners for electrographic applications
US7166405B2 (en) 2002-11-12 2007-01-23 Samsung Electronics Company Organosol including high Tg amphipathic copolymeric binder and liquid toners for electrophotographic applications
US7052816B2 (en) 2003-01-03 2006-05-30 Samsung Electronics Company Organosol liquid toner including amphipathic copolymeric binder having crosslinkable functionality

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