EP0453762B1 - Procédé et appareil de formation d'images utilisant un élément de transfert intermédiaire - Google Patents

Procédé et appareil de formation d'images utilisant un élément de transfert intermédiaire Download PDF

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Publication number
EP0453762B1
EP0453762B1 EP19910104271 EP91104271A EP0453762B1 EP 0453762 B1 EP0453762 B1 EP 0453762B1 EP 19910104271 EP19910104271 EP 19910104271 EP 91104271 A EP91104271 A EP 91104271A EP 0453762 B1 EP0453762 B1 EP 0453762B1
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EP
European Patent Office
Prior art keywords
intermediate transfer
image
transfer element
substrate
imaging
Prior art date
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EP19910104271
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German (de)
English (en)
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EP0453762A2 (fr
EP0453762A3 (en
Inventor
John S. Berkes
Frank J. Bonsignore
Joseph Mammino
Dennis A. Abramsohn
Donald S. Sypula
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Xerox Corp
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Xerox Corp
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Publication of EP0453762A3 publication Critical patent/EP0453762A3/en
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Classifications

    • 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
    • G03G7/0006—Cover layers for image-receiving members; Strippable coversheets
    • G03G7/002—Organic components thereof
    • G03G7/0026—Organic components thereof being macromolecular
    • G03G7/0046—Organic components thereof being macromolecular obtained otherwise than by reactions only involving carbon-to-carbon unsaturated bonds
    • 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
    • G03G15/162—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 details of the the intermediate support, e.g. chemical composition
    • 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
    • G03G7/0006—Cover layers for image-receiving members; Strippable coversheets
    • G03G7/002—Organic components thereof
    • G03G7/0026—Organic components thereof being macromolecular
    • G03G7/004—Organic components thereof being macromolecular obtained by reactions only involving carbon-to-carbon unsaturated bonds
    • 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
    • G03G7/006—Substrates for image-receiving members; Image-receiving members comprising only one layer
    • G03G7/0066—Inorganic components thereof
    • 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
    • G03G7/006—Substrates for image-receiving members; Image-receiving members comprising only one layer
    • G03G7/0073—Organic components thereof
    • G03G7/008—Organic components thereof being macromolecular

Definitions

  • the present invention is directed to an imaging apparatus and process according to the preamble of claim 1 and 12, respectively. More specifically, the present invention is directed to an imaging apparatus and process wherein an electrostatic latent image is formed on an imaging member and developed with a toner, followed by transfer of the developed image to an intermediate transfer element and subsequent transfer with very high transfer efficiency of the developed image from the intermediate transfer element to a permanent substrate, wherein the intermediate transfer element has a charge relaxation time of no more than about 2 ⁇ 10 2 seconds.
  • the formation and development of images on the surface of photoconductive materials by electrostatic means is well known.
  • the basic electrophotographic imaging process as taught by C.F. Carlson in U.S. Patent 2,297,691, entails placing a uniform electrostatic charge on a photoconductive insulating layer known as a photoconductor or photoreceptor, exposing the photoreceptor to a light and shadow image to dissipate the charge on the areas of the photoreceptor exposed to the light, and developing the resulting electrostatic latent image by depositing on the image a finely divided electroscopic material known as toner.
  • the toner will normally be attracted to those areas of the photoreceptor which retain a charge, thereby forming a toner image corresponding to the electrostatic latent image.
  • This developed image may then be transferred to a substrate such as paper.
  • the transferred image may subsequently be permanently affixed to the substrate by heat, pressure, a combination of heat and pressure, or other suitable fixing means such as solvent or overcoating
  • ionographic imaging processes a latent image is formed on a dielectric image receptor or electroreceptor by ion deposition, as described, for example, in U.S. Patent 3,564,556, U.S. Patent 3,611,419, U.S. Patent 4,240,084, U.S. Patent 4,569,584, U.S. Patent 2,919,171, U.S. Patent 4,524,371, U.S. Patent 4,619,515, U.S. Patent 4,463,363, U.S. Patent 4,254,424, U.S. Patent 4,538,163, U.S. Patent 4,409,604, U.S. Patent 4,408,214, U.S.
  • the process entails application of charge in an image pattern with an ionographic writing head to a dielectric receiver that retains the charged image.
  • the image is subsequently developed with a developer capable of developing charge images.
  • U.S. Patent 3,862,848 discloses an electrostatic method for the reproduction of printed matter in which an electrostatic latent image is developed by the attraction of electroscopic marking particles thereto and is then transferred to a first receptor surface by the simultaneous application of contact and a directional electrostatic field of a polarity to urge the marking particles to the receptor surface, with the image then being transferred from the first receptor surface to a second receptor surface by the simultaneous application of contact and a directional electrostatic field of opposite polarity to urge the marking particles to the second receptor surface.
  • U.S. Patent 3,957,367 discloses a color electrostatographic printing machine in which successive single color powder images are transferred, in superimposed registration with one another, to an intermediary.
  • the multi-layered powder image is fused on the intermediary and transferred therefrom to a sheet of support material, forming a copy of the original document.
  • U.S. Patent 4,341,455 discloses an apparatus for transferring magnetic and conducting toner from a dielectric surface to plain paper by interposing a dielectric belt mechanism between the dielectric surface of an imaging drum and a plain paper substrate such that the toner is first transferred to the dielectric belt and subsequently transferred to a plain paper in a fusing station.
  • the dielectic belt is preferably a material such as Teflon or polyethylene to which toner particles will not stick as they are fused in the heat-fuser station.
  • U.S. Patent 3,537,786 discloses a copying machine using a material capable of being persistently internally polarized as the latent image storage means.
  • a removable insulative carrier is applied to the storage means and receives a toner which clings to the carrier in correspondence with a previously applied image pattern.
  • the carrier is then removed from contact with the storage means and forms a record of the recorded image.
  • the insulative carrier is then passed over a heater to fix the toner so that the insulative carrier forms the final image bearing means.
  • the insulative carrier bearing the toner is brought into contact with a separate image bearing medium so as to transfer the toner to this image bearing medium which then acts as the final image bearing means.
  • the insulative carrier can be of a material such as polyethylene, polypropylene, polyethylene glycol terephthalate (Mylar®), polyeterafluoroethylene (Teflon®), polyvinylidene-acrylonitrile copolymers (Saran®), cellulose nitrate, cellulose acetate, acrylonitrile-butadiene-styrene terpolymers, cyclicized rubbers, and similar irradiation transparent, essentially non-photopolarizable organic or inorganic materials having a volume resistivity greater than 10 9 ohm-cm.
  • U.S. Patent 3,893,761 discloses an apparatus for transferring non-fused xerographic toner images from a first support material, such as a photoconductive insulating surface, to a second support material, such as paper, and fusing the toner images to the second support material.
  • a first support material such as a photoconductive insulating surface
  • a second support material such as paper
  • Such apparatus includes an intermediate transfer member having a smooth surface of low surface free energy below 40 dynes per centimeter and a hardness of from 3 to 70 durometers.
  • the intermediate transfer member can be, for example, a 0.1 to 10 mil layer of silicone rubber or a fluoroelastomer coated onto a polyimide support.
  • the member can be formed into belt or drum configuration.
  • Toner images are transferred from the first support material to the intermediate transfer member by any conventional method, preferably pressure transfer.
  • the toner image is then heated on the intermediate transfer member to at least its meiting point temperature, with heating preferably being selective.
  • the second support material is brought into pressure contact with the hot toner whereby the toner is transferred and fused to the second support material.
  • U.S. Patent 4,275,134 discloses an electrophotographic process using a photosensitive medium having an insulating layer on a photoconductive layer, the surface of the photosensitive medium being uniformly charged with a primary charge.
  • the primary-charged surface of the photosensitive medium is then charged with a charge of the opposite polarity or discharged and simultaneously therewith or therebefore or thereafter, exposed to image light from an original.
  • a grid image is projected upon the surface of the suface of the photosensitive medium.
  • the steps can be repeated in accordance with the number of colors desired.
  • the color images are transferred onto an intermediate drum which can be, for example, coated with a layer of Teflon®.
  • U.S. Patent 4,682,880 discloses a process wherein an electrostatic latent image is formed on a rotatable latent image bearing member and is developed with a developer into a visualized image.
  • the visualized image is transferred by pressure to a rotatable visualized image bearing member.
  • the steps are repealed with different color developers to form on the same visualized image bearing member a multi-color image which corresponds to one final image to be recorded.
  • the latent image bearing member and the visualized image bearing member form a nip therebetween through which a recording material is passed so that the multi-color image is transferred all at once to a recording material.
  • U.S. Patent 2,885,955 discloses an apparatus for printing on print-receiving material of a type liable to dimensional change or change in other physical characteristics when subjected to xerographic heat or vapor fixing techniques.
  • the apparatus contains a rotatable xerographic cylinder having an image forming surface with a photoconductive layer and a means for rotating the cylinder through a predetermined path of movement relative to a plurality of xerographic processing stations, including a charging station for applying electric charge to the photoconductive layer, an exposure station with a projection means for projecting a light image onto the charge photoconductive layer to form an electrostatic latent image, and a developing station having a means for depositing powdered developing material on the photoconductive layer to develop the latent image.
  • the apparatus contains a means for supporting a web of water receptive planographic printing material, a means for moving the web in surface contact with the photoconductive layer through a portion of its path of movement, a transfer means for transferring the developed image from the photoconductive layer to the web surface while the photoconductive layer and the web are in surface contact, a fixing means for fixing the developed image on the web surface, a means for applying an aqueous solution to the surface of the web, a means for applying lithographic ink to the fixed powder image on the web surface, a feeding means for feeding print receiving material into surface contact with the inked surface of the web, and a means for pressing the print-receiving material into intimate surface contact with the inked powder image on the web surface.
  • U.S. Patent 3,526,191 discloses a duplicating process wherein magnetic images of copy to be reproduced are created and used to attract magnetically attractable powder to form subsequent reproductions of the original copy.
  • the magnetic images are deposited and fused to a sheet to form a master.
  • the magnetic field extending from the master can be used to either attract magnetic toner directly to the fused image on the master with subsequent transfer to a copy sheet or the field can extend through a copy sheet placed over the master to attract magnetic toner to the copy sheet in the pattern of the master image.
  • the toner images are then fused to the copy sheet.
  • Mirror images can be avoided by transferring the toner images to intermediate surfaces or by producing the master in a reverse reading form.
  • U.S. Patent 3,804,511 (Rait et al.) and U.S. Patent 3,993,484 (Rait et al.) disclose a process wherein an electrostatic image is formed on a surface and magnetic toner paticles are then applied to the surface and adhere thereto in correspondence with the electrostatic image. Portions of the same surface or another surface are magnetized, as determined by the location of the toner particles, to form a magnetic image corresponding to the electrostatic image. The toner particles are then transferred by friction to a copy medium such as paper while the magnetic image is retained or stored on the surface. Toner particles can then again be applied to the magnetic image for production of additional copies.
  • the intermediate transfer member is held in registration at the transfer station for transferring images from the xerographic drums to the member by a hole-and-sprocket arrangement, wherein sprockets on the edges of the drums engage holes in the edge of the intermediate transfer member.
  • Intermediate transfer elements employed in imaging apparatuses in which a developed image is first transferred from the imaging member to the intermediate and then transferred from the intermediate to a substrate should exhibit both good transfer of the developer material from the imaging member to the intermediate and good transfer of the developer material from the intermediate to the substrate.
  • Good transfer occurs when most or all of the developer material comprising the image is transferred and little residual developer remains on the surface from which the image was transferred.
  • Good transfer is particularly important when the imaging process entails generating full color images by sequentially generating and developing images in each primary color in succession and superimposing the primary color images onto each other on the substrate, since undesirable shifting and variation in the final colors obtained can occur when the primary color images are not efficiently transferred to the substrate.
  • JP-A-62191863 An apparatus and a method having the features of the preamble of claim 1 and 12, respectively, is known from JP-A-62191863.
  • an intermediate transfer element polyester which is a dielectric is wound to a transfer drum.
  • This document discloses a dielectric constant of 3.0 to 13.0, a volume resistance of 10 3 to 10 16 , a thickness of 17 to 200 mm of the transfer element. If at least two of these conditions are satisfied and also a critical surface tension is set to 40dyn/cm or below a colour toner image can be brought to a multiple transfer satisfactorily onto a transfer image.
  • a transfer system for an electrophotographic printing apparatus which system includes a transfer web.
  • the bulk resistivity of the transfer belt is in the range of 10 7 to 10 10 ohm centimetres and a surface resistivity of the belt is in the range of 10 7 to 10 10 ohms per square.
  • Another object of the present invention is to provide imaging apparatuses and processes employing intermediate transfer elements that enable simplified and improved registration of superimposed images of different colors on a single substrate sheet to form multicolor or blended color images.
  • the apparatus and process of the present invention can employ any means for generating and developing the latent electrostatic image.
  • electrophotographic processes can be employed, wherein an image is formed on an imaging member by exposure of a photosensitive imaging member to light in an imagewise pattern.
  • the image can be generated by ionographic processes, wherein the image is formed on a dielectric imaging member by applying a charge pattern to the imaging member in imagewise fashion.
  • any suitable developing processes and materials can be employed with the present invention.
  • dry development processes can be employed, either single component development processes in which the developer material consists essentially of toner particles, or two component development processes, wherein the developer material comprises toner particles and carrier particles.
  • Typical toner particles can be of any composition suitable for development of electrostatic latent images, such as those comprising a resin and a colorant.
  • Typical toner resins include polyesters, polyamides, epoxies, polyurethanes, diolefins, vinyl resins and polymeric esterification products of a dicarboxylic acid and a diol comprising a diphenol.
  • vinyl monomers include styrene, p-chlorostyrene, vinyl naphthalene, unsaturated mono-olefins such as ethylene, propylene, butylene, isobutylene and the like; vinyl halides such as vinyl chloride, vinyl bromide, vinyl fluoride, vinyl acetate, vinyl propionate, vinyl benzoate, and vinyl butyrate; vinyl esters such as esters of monocarboxylic acids, including methyl acrylate, ethyl acrylate, n-butyl acrylate, isobutyl acrylate, dodecyl acrylate, n-octyl acrylate, 2-chloroethyl acrylate, phenyl acrylate, methylalpha-chloroacrylate, methyl methacrylate, ethyl methacrylate, butyl methacrylate, and the like; acrylonitrile, methacrylonitrile, acrylamide, vinyl ether
  • any suitable pigments or dyes or mixture thereof can be employed in the toner particles.
  • Typical pigments or dyes include carbon black, nigrosine dye, aniline blue, magnetites, and mixtures thereof, with carbon black being a preferred colorant.
  • the pigment is preferably present in an amount sufficient to render the toner composition highly colored to permit the formation of a clearly visible image on a recording member.
  • the pigment particles are present in amounts of from about 1 percent by weight to about 20 percent by weight based on the total weight of the toner composition; however, lesser or greater amounts of pigment particles can be present provided that the objectives of the present invention are achieved.
  • magenta pigments include red, green, blue, brown, magenta, cyan, and yellow particles, as well as mixtures thereof.
  • suitable magenta pigments include 2,9-dimethyl-substituted quinacridone and anthraquinone dye, identified in the Color Index as Cl 60710, Cl Dispersed Red 15, a diazo dye identified in the Color Index as Cl 26050, Cl Solvent Red 19, and the like.
  • Suitable cyan pigments include copper tetra-4-(octadecyl sulfonamido) phthalocyanine, X-copper phthalocyanine pigment, listed in the Color Index as Cl 74160, Cl Pigment Blue, and Anthradanthrene Blue, identified in the Color Index as Cl 69810, Special Blue X-2137, and the like.
  • yellow pigments that can be selected include diarylide yellow 3,3-dichlorobenzidene acetoacetanilides, a monoazo pigment identified in the Color Index as Cl 12700, Cl Solvent Yellow 16, a nitrophenyl amine sulfonamide identified in the Color Index as Foron Yellow SE/GLN, Cl Dispersed Yellow 33, 2,5-dimethoxy-4-sulfonanilide phenylazo-4'-chloro-2,5-dimethoxy aceto-acetanilide, Permanent Yellow FGL, and the like.
  • These color pigments are generally present in an amount of from about 5 weight percent to about 20.5 weight percent based on the weight of the toner resin particles, although lesser or greater amounts can be present provided that the objectives of the present invention are met.
  • pigment particles are magnetites, which comprise a mixture of iron oxides (Fe 3 O 4 ), such as those commercially available as Mapico Black
  • these pigments are present in the toner composition in an amount of from about 10 percent by weight to about 70 percent by weight, and preferably in an amount of from about 20 percent by weight to about 50 percent by weight, although they can be present in greater or lesser amounts, provided that the objectives of the invention are achieved.
  • the toner compositions can be prepared by any suitable method.
  • a method known as spray drying entails dissolving the appropriate polymer or resin in an organic solvent such as toluene or chloroform, or a suitable solvent mixture.
  • the toner colorant is also added to the solvent. Vigorous agitation, such as that obtained by ball milling processes, assists in assuring good dispersion of the colorant.
  • the solution is then pumped through an atomizing nozzle while using an inert gas, such as nitrogen, as the atomizing agent.
  • the solvent evaporates during atomization, resulting in toner particles of a pigmented resin, which are then attrited and classified by particle size. Particle diameter of the resulting toner varies, depending on the size of the nozzle, and generally varies between about 0.1 and about 100 microns.
  • Banbury method a batch process wherein the dry toner ingredients are pre-blended and added to a Banbury mixer and mixed, at which point melting of the materials occurs from the heat energy generated by the mixing process.
  • the mixture is then dropped into heated rollers and forced through a nip, which results in further shear mixing to form a large thin sheet of the toner material.
  • This material is then reduced to pellet form and further reduced in size by grinding or jetting, after which the particles are classified by size.
  • a third suitable toner preparation process, extrusion is a continuous process that entails dry blending the toner ingredients, placing them into an extruder, melting and mixing the mixture, extruding the material, and reducing the extruded material to pellet form.
  • the pellets are further reduced in size by grinding or jetting, and are then classified by particle size.
  • Dry toner particles for two-component developers generally have an average particle size between about 6 micrometers and about 20 micrometers. Other similar blending methods may also be used.
  • any external additives are blended with the toner particles.
  • the resulting toner composition is then mixed with carrier particles such that the toner is present in an amount of about 1 to about 5 percent by weight of the carrier, and preferably about 3 percent by weight of the carrier, although different toner to carrier ratios are acceptable, provided that the objectives of the present invention are achieved.
  • any suitable external additives can also be utilized with the dry toner particles.
  • the amounts of external additives are measured in terms of percentage by weight of the toner composition, but are not themselves included when calculating the percentage composition of the toner.
  • a toner composition containing a resin, a pigment, and an external additive can comprise 80 percent by weight of resin and 20 percent by weight of pigment; the amount of external additive present is reported in terms of its percent by weight of the combined resin and pigment.
  • External additives can include any additives suitable for use in electrostatographic toners, including straight silica, colloidal silica (e.g.
  • Aerosil R972® available from Degussa, Inc.
  • ferric oxide unilin
  • Unilin polypropylene waxes
  • polymethylmethacrylate zinc stearate
  • chromium oxide aluminum oxide
  • stearic acid polyvinylidene flouride (e.g. Kynar®, available from Pennwalt Chemicals Corporation), and the like.
  • External additives can be present in any suitable amount, provided that the objectives of the present invention are achieved.
  • any suitable carrier particles can be employed with the toner particles.
  • Typical carrier particles include granular zircon, steel, nickel, iron ferrites, and the like.
  • Other typical carrier particles include nickel berry carriers as disclosed in U.S. Patent 3,847,604. These carriers comprise nodular carrier beads of nickel characterized by surfaces of reoccurring recesses and protrusions that provide the particles with a relatively large external area.
  • the diameters of the carrier particles can vary, but are generally from about 50 microns to about 1,000 microns, thus allowing the particles to possess sufficient density and inertia to avoid adherence to the electrostatic images during the development process.
  • Carrier particles can possess coated surfaces.
  • Typical coating materials include polymers and terpolymers, including, for example, fluoropolymers such as polyvinylidene fluorides as disclosed in U.S. Patent 3,526,533, U.S. Patent 3,849,186, and U.S. Patent 3,942,979.
  • the toner may be present, for example, in the two-component developer in an amount equal to about 1 to about 5 percent by weight of the carrier, and preferably is equal to about 3 percent by weight of the carrier.
  • Typical dry toners are disclosed in, for example, U.S. Patent 2,788,288, U.S. Patent 3,079,342, and U.S. Patent Reissue 25,136.
  • liquid developers are disclosed, for example, in U.S. Patent 2,890,174 and U.S. Patent 2,899,335.
  • Any suitable conventional electrophotographic development technique can be utilized to deposit toner particles on the electrostatic latent image on the imaging member.
  • Well known electrophotographic development techniques include magnetic brush development, cascade development, powder cloud development, electrophoretic development, and the like. Magnetic brush development is more fully described in, for example, U.S. Patent 2,791,949 cascade development is more fully described in, for example, U.S. Patent 2,618,551 and U.S. Patent 2,618,552, powder cloud development is more fully described in, for example, U.S. Patent 2,725,305, U.S. Patent 2,918,910, and U.S. Patent 3,015,305 and liquid development is more fully described in, for example, U.S. Patent 3,084,043.
  • the transfer element employed for the present invention can be of any suitable configuration.
  • suitable configurations include a sheet, a web, a foil, a strip, a coil, a cylinder, a drum, an endless belt, an endless mobius strip, a circular disc, or the like.
  • the transfer element has a thickness of from about 2 to about 10 mils.
  • the transfer elements of the present invention have a charge relaxation time of no more than about 2 ⁇ 10 2 seconds to ensure efficient transfer from the intermediate to the substrate.
  • the lower limit of suitable charge relaxation times is theoretically unlimited, and conductive materials such as metals can be employed as the transfer element. While not being limited by any theory, however, it is believed that the lower limit on the charge relaxation time for an intermediate transfer element in any given situation will be determined by the conductivity of the receiving substrate to which the toner image is ultimately transferred. Specifically, no shorting should occur between the intermediate transfer element and the substrate around the toner piles constituting the image, since shorting would result in little or no transfer field to effect transfer from the intermediate to the substrate.
  • the charge relaxation time is from about 1 ⁇ 10 -3 seconds to about 2 ⁇ 10 2 seconds.
  • materials having suitable charge relaxation times include polyvinyl fluoride, such as Tedlar®, available from E. I.
  • polyvinyl fluoride loaded with conductive or dielectric fillers such as carbon particles, titanium dioxide, barium titanate, or any other filler capable of decreasing dielectric thickness
  • polyvinylidene fluoride such as Kynar®, available from Pennwalt Corporation
  • polyvinylidene fluoride loaded with conductive or dielectric fillers such as carbon particles, titanium dioxide, barium titanate, or any other filler capable of decreasing dielectric thickness
  • paper such as Xerox® 4024 paper or Xerox® Series 10 paper, and the like.
  • Metal oxides, including tin oxide, indium tin oxide, and the like, are also suitable. Any other material having the charge relaxation characteristics described herein can also be employed.
  • Fillers employed to alter the relaxation time of a material may be present within that material in any amount necessary to effect the desired relaxation time; typically, fillers are present in amounts of from 0 to about 50 percent by weight.
  • the relative humidity may have to be controlled during the imaging process to maintain the intermediate transfer element at the desired charge relaxation time.
  • intermediate transfer elements of materials for which the charge relaxation time changes significantly with relative humidity perform optimally at relative humidities of 55 percent or less.
  • the developed image on the intermediate transfer element is subsequently transferred to a substrate.
  • the developed image on the intermediate is charged by, for example, exposure to a corotron to ensure that all of the toner particles are charged to the same polarity, thereby enhancing transfer efficiency by eliminating any wrong-sign toner.
  • Wrong-sign toner is toner particles that have become charged to a polarity opposite to that of the majority of the toner particles and the same as the polarity of the latent image. Wrong-sign toner particles typically are difficult to transfer to a substrate. Examples of substrates include paper, transparency material such as polyester, polycarbonate, or the like, cloth, wood, or any other desired material upon which the finished image will be situated.
  • the transferred developed image can thereafter be fused to the substrate by conventional means.
  • Typical, well known electrophotographic fusing techniques include heated roll fusing, flash fusing, oven fusing, laminating, vapor fusing, adhesive spray fixing, and the like.
  • transfer of the developed image from the imaging member to the intermediate transfer element and transfer of the image from the intermediate transfer element to the substrate can be by any suitable technique conventionally used in electrophotography, such as corona transfer, pressure transfer, bias roll transfer, and the like.
  • transfer methods such as adhesive transfer, wherein the receiving substrate has adhesive characteristics with respect to the developer material, can also be employed.
  • Typical corona transfer entails contacting the deposited toner particles with the substrate and applying an electrostatic charge on the surface of the substrate opposite to the toner particles.
  • a single wire corotron having applied thereto a potential of between about 5000 and about 8000 volts provides satisfactory transfer.
  • a corona generating device sprays the back side of the image receiving member with ions to charge it to the proper potential so that it is tacked to the member from which the image is to be transferred and the toner powder image is attracted from the image bearing member to the image receiving member.
  • a corona generator charges the receiving member to an opposite polarity to detack the receiving member from the member that originally bore the developed image, whereupon the image receiving member is separated from the member that originally bore the image.
  • Bias roll transfer is another method of effecting transfer of a developed image from one member to another.
  • a biased transfer roller or belt rolls along the surface of the receiving member opposite to the surface that is to receive the developed image.
  • Further information concerning bias roll transfer methods is disclosed in, for example, U.S. Patent 2,807,233, U.S. Patent 3,043,684, U.S. Patent 3,267,840, U.S. Patent 3,328,193, U.S. Patent 3,598,580, U.S. Patent 3,625,146, U.S. Patent 3,630,591, U.S. Patent 3,684,364, U.S. Patent 3,691,993, U.S. Patent 3,702,482, U.S. Patent 3,781,105, U.S. Patent 3,832,055, U.S. Patent 3,847,478, U.S. Patent 3,942,888, and U.S. Patent 3,924,943.
  • Intermediate transfer elements comprising 21,59 by 27.94 cm (8.5 by 11 inch) sheets having a thickness of 4 mils (100 microns) of the materials indicated in the table below were prepared and passed through a Xerox® 6500 copier.
  • Magenta images were generated by forming a latent image, developing the image with a negatively charged magenta toner, and transferring the magenta image to the intermediate.
  • the toner mass of the developed image prior to transfer to the substrate was about 1.0 milligram per square centimeter. Prior to transfer, the developed image on the intermediate was charged negatively by a corotron to eliminate any wrong-sign toner.
  • Transfer to the substrate was effected by placing the intermediate transfer element on a conductive ground plane, placing a piece of Xerox® Series 10 substrate paper in contact with the image on the intermediate, and passing the substrate paper and intermediate through a nip formed between the ground plane and a bias transfer roller.
  • the bias transfer roller was obtained from a Xerox® 9200 copier, and comprised a 2.54 cm (1 inch) diameter aluminum tube coated with a 0.63 cm (1/4 inch) coating of urethane doped to render the coating conductive, with the length (l) of the coated portion of the roller being 20.32 cm (8 inches).
  • the table below indicates the dielectric constant (K), the volume resistivity ( ⁇ ), and the charge relaxation time ( ⁇ ) for each material tested and also indicates the percentage of toner transferred from the intermediate transfer element to the substrate for each material (% Trans.). All transfers were effected under relative humidity conditions of about 25 percent.
  • Du Pont de Nemours & Company 98 10 -3 8 10 9 Paper (Xerox® Series 10, Xerox Corporation) 97 3 ⁇ 10 -1 3.5 10 12 Paper (Xerox® 4024 DP, Xerox Corporation) 98 3 ⁇ 10 -1 3.5 10 12 Polyvinyl fluoride (Tedlar®, E.I. Du Pont de Nemours & Company) 97.5 3 ⁇ 10 1 8.5 4 ⁇ 10 13 Polyvinyl fluoride (Tedlar®, loaded with 10 percent by weight TiO 2 particles, E.I.
  • Du Pont de Nemours & Company 98 8 ⁇ 10 1 11.0 7 ⁇ 10 13 Polyvinylidene fluoride (Kynar®, Pennwalt Corporation) 98 1.6 ⁇ 10 2 8.4 2 ⁇ 10 14 Nylon 12 (electrodeposited) 87 4 ⁇ 10 2 3.8 10 15 Polyimide (Kapton® HV, E.I. Du Pont de Nemours & Company) 82 4 ⁇ 10 4 3.7 10 17 Polyeterafluoroethylene (Teflon®, E.I. Du Pont de Nemours & Company) 74 2 ⁇ 10 3 2.0 10 16 Polyether ether ketone (Victrex®, E.I.
  • Du Pont de Nemours & Company 78 1 ⁇ 10 4 3.3 4 ⁇ 10 16 Polyethylene terephthalate (Mylar®, E.I. Du Pont de Nemours & Company) 63 > 10 4 3.0 > 10 17 Polysulfone (Thermalux®, Westlake Plastics Company) 54 1 ⁇ 10 4 3.0 5 ⁇ 10 16 Polyethersulfone (Victrex® PES, ICI Americas Company) 60 > 10 4 3.5 5 ⁇ 10 18 Polyetherimide (Ultrem®, General Electric Company) 63 2 ⁇ 10 5 3.1 7 ⁇ 10 17 Polymethylpentane (TPX®, Mitsui Petrochemical Industries) 33 > 10 3 2.0 > 10 16
  • the transfer elements formulated from materials having a charge relaxation time of 2 ⁇ 10 2 seconds or less exhibited excellent transfer efficiencies of over 95 percent.
  • the Nylon 12 transfer element, with a charge relaxation time of 4 ⁇ 10 2 seconds, exhibited a significantly lower transfer efficiency of 87 percent, and the materials having higher charge relaxation times exhibited even lower transfer efficiencies ranging from 33 percent to 82 percent.
  • these improved transfer efficiency results are not a function of the smoothness or surface energy of the materials, since rough, high surface energy (40 dynes per square centimeter) materials such as paper exhibited excellent transfer efficiency, whereas very smooth, low surface energy materials such as Teflon® (surface energy 19 dynes per square centimeter) exhibited relatively poor transfer efficiency.
  • Intermediate transfer elements of the materials indicated in the table below comprising 21.59 cm by 27.94 cm (8.5 by 11 inch) sheets having a thickness of 4 mils (100 microns) were prepared and passed through a Xerox® 6500 copier. Images were generated by forming a latent image, developing the image with a negatively charged toner of either magenta, cyan, or yellow color, and transferring the image to the intermediate. The toner mass of the developed color image on each intermediate transfer element prior to transfer to the substrate was about 1.1 milligrams per square centimeter. Prior to transfer, the developed image on the intermediate was charged negatively by a corotron to eliminate any wrong-sign toner.
  • Transfer to the substrate was effected by placing the intermediate transfer element on a conductive ground plane, placing a piece of Xerox® Series 10 substrate paper in contact with the image on the intermediate, and passing the ground plane-intermediate-paper substrate sandwich under a transfer corotron charged at 5.5 kilovolts and +0.8 microamperes per 2.54 cm (inch) at a speed 10,16 cm (4 inches) per second.
  • the table below indicates the dielectric constant (K), the volume resistivity ( ⁇ ), and the charge relaxation time ( ⁇ ) for each material tested and also indicates the percentage of toner transferred from the intermediate transfer element to the substrate for each material (% Trans.). All transfers were effected under relative humidity conditions of about 25 percent. Intermediate Material % Trans.
  • the transfer elements formulated from materials having a charge relaxation time constant of 2 ⁇ 10 2 seconds or less exhibited transfer efficiencies of over 90 percent.
  • Tedlar® polyvinyl fluoride
  • Full color images were generated by forming a first latent image, developing the image with a negatively charged magenta toner, transferring the magenta image to the intermediate, forming a second latent image, developing the image with a negatively charged yellow toner, transferring the yellow image to the intermediate on top of the magenta image, forming a third latent image, developing the image with a negatively charged cyan toner, and transferring the cyan image to the intermediate on top of the magenta and yellow images.
  • the toner mass of the developed full color image prior to transfer to the substrate was about 2.0 milligrams per square centimeter. Prior to transfer, the developed image on the intermediate was charged negatively by a corotron to eliminate any wrong-sign toner.
  • Transfer to the substrate was effected by placing the intermediate transfer element on a conductive ground plane, placing a piece of Xerox® Series 10 substrate paper in contact with the image on the intermediate, and passing the substrate paper and intermediate through a nip formed between the ground plane and a bias transfer roller.
  • the bias transfer roller was obtained from a Xerox® 9200 copier, and comprised a 2.54 cm (1 inch) diameter aluminum tube coated with a 0.63 cm (1/4 inch) coating of urethane doped to render the coating conductive, with the length (l) of the coated portion of the roller being 8 inches.
  • the intermediate transfer element and substrate passed through the bias transfer roller nip at a speed of 4 inches per second, and a + 5.6 microampere current was passed through the bias transfer roller, resulting in a field during transfer of 30 volts per micron.
  • the pressure in the transfer nip was about 0.25 kg (0.5 pound) per lineal inch. Transfer was effected under relative humidity conditions of about 25 percent. The full color image was transferred to the paper substrate with a transfer efficiency of 97 to 98 percent.
  • Tedlar® polyvinyl fluoride
  • TiO 2 polyvinyl fluoride
  • Tedlar® polyvinyl fluoride
  • Full color images were generated by forming a first latent image, developing the image with a negatively charged magenta toner, transferring the magenta image to the intermediate, forming a second latent image, developing the image with a negatively charged cyan toner, transferring the cyan image to the intermediate on top of the magenta image, forming a third latent image, developing the image with a negatively charged yellow toner, transferring the yellow image to the intermediate on top of the magenta and cyan images, forming a fourth latent image, developing the image with a negatively charged black toner, and transferring the black image to the intermediate on top of the magenta, cyan, and yellow images.
  • the toner mass of the developed full color image prior to transfer to the substrate was about 2.0 milligrams per square centimeter.
  • the developed image on the intermediate was charged negatively by a corotron to eliminate any wrong-sign toner.
  • Transfer to the substrate was effected by placing the intermediate transfer element on a conductive ground plane, placing a piece of Xerox® Series 10 substrate paper in contact with the image on the intermediate, and passing the substrate paper and intermediate through a nip formed between the ground plane and a bias transfer roller.
  • the bias transfer roller was obtained from a Xerox® 9200 copier, and comprised a 2.54 cm (1 inch) diameter aluminum tube coated with a 0.63 cm (1/4 inch) coating of urethane doped to render the coating conductive, with the length (l) of the coated portion of the roller being 21.59 cm (8 inches).
  • the intermediate transfer element and substrate passed through the bias transfer roller nip at a speed of 10,16 cm (4 inches) per second, and a + 5.6 microampere current was passed through the bias transfer roller, resulting in a field during transfer of 30 volts per micron.
  • the pressure in the transfer nip was about 0.25 kg (0.5 pound) per lineal 2.54 cm (inch). Transfer was effected under relative humidity conditions of about 25 percent.
  • the full color image was transferred to the paper substrate with a transfer efficiency of 96 to 97 percent.
  • Tedlar® polyvinyl fluoride
  • TiO 2 polyvinyl fluoride
  • Black images were generated by forming a latent image, developing the image with a positively charged black toner, and transferring the black image to the intermediate.
  • the toner mass of the developed image prior to transfer to the substrate was about 1.0 milligram per square centimeter. Prior to transfer, the developed image on the intermediate was charged positively by a corotron to eliminate any wrong-sign toner.
  • Transfer to the substrate was effected by placing the intermediate transfer element on a conductive ground plane, placing a piece of Xerox® Series 10 substrate paper in contact with the image on the intermediate, and passing the substrate paper and intermediate through a nip formed between the ground plane and a bias transfer roller.
  • the bias transfer roller was obtained from a Xerox® 9200 copier, and comprised a 2.54 cm (1 inch) diameter aluminum tube coated with a 1/4 inch coating of urethane doped to render the coating conductive, with the length (l) of the coated portion of the roller being 8 inches.
  • the intermediate transfer element and substrate passed through the bias transfer roller nip at a speed of 10.76 cm (4 inches) per second, and a -5.6 microampere current was passed through the bias transfer roller, resulting in a field during transfer of 30 volts per micron.
  • the pressure in the transfer nip was about 0.25 kg (0.5 pound) per lineal inch. Transfer was effected under relative humidity conditions of about 25 percent. The full color image was transferred to the paper substrate with a transfer efficiency of 97 percent.

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  • Physics & Mathematics (AREA)
  • General Physics & Mathematics (AREA)
  • Spectroscopy & Molecular Physics (AREA)
  • Chemical & Material Sciences (AREA)
  • Chemical Kinetics & Catalysis (AREA)
  • Inorganic Chemistry (AREA)
  • Electrostatic Charge, Transfer And Separation In Electrography (AREA)
  • Developing Agents For Electrophotography (AREA)

Claims (23)

  1. Appareil de formation d'image qui comprend un élément de formation d'image, un moyen destiné à générer une image latente électrostatique sur l'élément de formation d'image, un moyen destiné à développer l'image latente, un élément de transfert intermédiaire sur lequel l'image développée peut être transférée depuis l'élément de formation d'image, et un moyen destiné à transférer l'image développée depuis l'élément de transfert intermédiaire sur un substrat,
    caractérisé en ce que
    ledit moyen de transfert comprend un moyen destiné à charger l'image développée sur l'élément de transfert intermédiaire avant le transfert sur le substrat, et
    l'élément de transfert intermédiaire présente un temps de libération de charges ne dépassant pas environ 2 x 102 secondes de façon à obtenir un pourcentage de toner transféré depuis l'élément de transfert intermédiaire sur le substrat dépassant 90 %.
  2. Appareil de formation d'image selon la revendication 1, dans lequel l'élément de formation d'image est photosensible et le moyen destiné à générer une image latente électrostatique expose l'élément de formation d'image à la lumière d'une manière conforme à une image.
  3. Appareil de formation d'image selon la revendication 1, dans lequel l'élément de formation d'image est un diélectrique et le moyen destiné à générer une image latente électrostatique applique un motif de charges sur l'élément de formation d'image d'une manière conforme à une image.
  4. Appareil de formation d'image selon la revendication 1, dans lequel le moyen destiné à développer l'image latente utilise un développateur à sec.
  5. Appareil de formation d'image selon la revendication 1, dans lequel le moyen destiné à transférer l'image depuis l'élément de transfert intermédiaire sur un substrat est un dispositif corotron.
  6. Appareil de formation d'image selon la revendication 1, dans lequel le moyen destiné à transférer l'image depuis l'élément de transfert intermédiaire sur un substrat est un rouleau de transfert de polarisation.
  7. Appareil de formation d'image selon la revendication 1, dans lequel l'élément de transfert intermédiaire présente un temps de libération de charges allant d'environ 3 x 10-1 seconde à environ 2 x 102 secondes.
  8. Appareil de formation d'image selon la revendication 1, dans lequel la formule de l'élément de transfert intermédiaire est établie à partir d'un matériau sélectionné parmi le groupe constitué d'un fluorure de polyvinyle, d'un fluorure de polyvinyle contenant un matériau de remplissage, d'un fluorure de polyvinylidène, d'un fluorure de polyvinylidène contenant un matériaux de remplissage, et de papier.
  9. Appareil de formation d'image selon la revendication 8, dans lequel le matériau de remplissage est sélectionné dans le groupe constitué de carbone, de'dioxyde de titane, de titanate de baryum, et de mélanges de ceux-ci.
  10. Appareil de formation d'image selon la revendication 1, dans lequel la formule de l'élément de transfert intermédiaire est établie à partir d'un matériau sélectionné dans le groupe constitué des oxydes métalliques.
  11. Appareil de formation d'image selon la revendication 1, dans lequel l'élément de transfert intermédiaire et le substrat sont sélectionnés de façon à ce qu'aucun court-circuit n'apparaisse entre le transfert intermédiaire de l'image depuis l'élément de transfert intermédiaire sur le substrat.
  12. Processus de formation d'image qui comprend la génération d'une image latente électrostatique sur un élément de formation d'image, le développement de l'image latente, le transfert de l'image développée sur un élément de transfert intermédiaire et le transfert de l'image développée depuis l'élément de transfert intermédiaire sur un substrat,
    caractérisé en ce que
    l'image développée sur l'élément intermédiaire est chargée avant le transfert sur le substrat, et
    un élément de transfert intermédiaire est utilisé, lequel élément présente un temps de libération de charges ne dépassant pas 2 x 102 secondes de façon à obtenir un pourcentage de toner transféré depuis l'élément de transfert intermédiaire sur le substrat, dépassant 90%.
  13. Processus de formation d'image selon la revendication 12, dans lequel l'élément de formation d'image est photosensible et le moyen destiné à générer une image latente électrostatique expose l'élément d'image à la lumière, d'une manière conforme à une image.
  14. Processus de formation d'image selon la revendication 12, dans lequel l'élément de formation d'image est un diélectrique et le moyen destiné à générer une image latente électrostatique applique un motif de charges sur l'élément de formation d'image d'une manière conforme à une image.
  15. Processus de formation d'image selon la revendication 12, dans lequel le moyen destiné à développer l'image latente utilise un développateur sec.
  16. Processus de formation d'image selon la revendication 12, dans lequel le moyen destiné à transférer l'image depuis l'élément de transfert intermédiaire sur un substrat est un dispositif corotron.
  17. Processus de formation d'image selon la revendication 12, dans lequel le moyen destiné à transférer l'image depuis l'élément de transfert intermédiaire sur un substrat est un rouleau de transfert de polarisation.
  18. Processus de formation d'image selon la revendication 12, dans lequel l'élément de transfert intermédiaire présente un temps de libération de charges allant d'environ 3 x 10-1 seconde à environ 2 x 102 secondes.
  19. Processus de formation d'image selon la revendication 12, dans lequel l'élément de transfert intermédiaire est formulé à partir d'un matériau sélectionné parmi le groupe constitué d'un fluorure de polyvinyle, d'un fluorure de polyvinyle contenant un matériau de remplissage, d'un fluorure de polyvinylidène, d'un fluorure de polyvinylidène contenant un matériau de remplissage, et de papier.
  20. Processus de formation d'image selon la revendication 19, dans lequel le matériau de remplissage est sélectionné à partir du groupe constitué du carbone, du dioxyde de titane et du titanate de baryum.
  21. Processus de formation d'image selon la revendication 12, dans lequel l'élément de transfert intermédiaire est formulé à partir d'un matériau sélectionné dans le groupe constitué d'oxydes métalliques.
  22. Processus de formation d'image selon la revendication 12, dans lequel l'élément de transfert intermédiaire et le substrat sont sélectionnés de façon à ce qu'aucun court-circuit n'apparaisse entre l'élément de transfert intermédiaire et le substrat pendant le transfert de l'image depuis l'élément de transfert intermédiaire sur le substrat.
  23. Processus de formation d'image selon la revendication 12, dans lequel l'image développée est chargée à une seule polarité afin d'éliminer le toner de mauvais signe.
EP19910104271 1990-04-23 1991-03-19 Procédé et appareil de formation d'images utilisant un élément de transfert intermédiaire Expired - Lifetime EP0453762B1 (fr)

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US51340890A 1990-04-23 1990-04-23
US513408 1990-04-23

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EP0453762A3 EP0453762A3 (en) 1993-04-28
EP0453762B1 true EP0453762B1 (fr) 1996-09-18

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* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US5428429A (en) * 1991-12-23 1995-06-27 Xerox Corporation Resistive intermediate transfer member
US5357330A (en) * 1992-11-12 1994-10-18 Xerox Corporation Multilayer toner transfer ordering
DE19502098C2 (de) * 1994-01-24 2001-02-22 Ricoh Kk Zwischenbild-Übertragungselement und Bilderzeugungseinrichtung mit diesem Element
US5715510A (en) * 1994-11-28 1998-02-03 Canon Kabushiki Kaisha Image forming apparatus having an intermediate transfer member and method of forming of image using the transfer member
EP0716355B1 (fr) * 1994-12-06 2000-02-09 Canon Kabushiki Kaisha Appareil de formation d'images utilisant un transfert intermédiate et méthode de formation d'images l'utilisant
NL1001471C2 (nl) * 1995-10-23 1997-04-25 Oce Nederland Bv Inrichting voor het overdragen van een tonerbeeld van een beeldvormings- medium naar een ontvangstmateriaal.
DE69633372D1 (de) * 1995-10-23 2004-10-21 Oce Tech Bv Verlängerte difunktionelle Perfluoropolyether-Öle und daraus hergestellte Kautschuks
DE19921321C1 (de) 1998-10-27 2000-11-23 Schott Glas Vorrichtung zum Aufbringen von Dekors und/oder Zeichen auf Glas-, Glaskeramik- und Keramikerzeugnisse
DE19849500C2 (de) * 1998-10-27 2000-12-21 Schott Glas Verfahren zum Aufbringen von Dekors und/oder Zeichen auf Glas-, Glaskeramik- und Keramikerzeugnisse
DE10001452C2 (de) * 2000-01-15 2002-04-25 Schott Glas Vorrichtung zum Bedrucken von Papier oder plattenförmigen Werkstoffen

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Publication number Priority date Publication date Assignee Title
JPS5423543A (en) * 1977-07-22 1979-02-22 Canon Inc Image former
JPS5723975A (en) * 1980-07-18 1982-02-08 Konishiroku Photo Ind Co Ltd Intermediate copying body
US4674860A (en) * 1984-08-21 1987-06-23 Konishiroku Photo Industry Co. Image transfer device
US4606955A (en) * 1985-06-18 1986-08-19 E. I. Du Pont De Nemours And Company Conductive pyrolyzed dielectrics and articles made therefrom
US4931839A (en) * 1988-03-11 1990-06-05 Colorocs Corporation Transfer system for electrophotographic print engine

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DE69122156T2 (de) 1997-01-30
EP0453762A2 (fr) 1991-10-30
JPH04230781A (ja) 1992-08-19
EP0453762A3 (en) 1993-04-28
DE69122156D1 (de) 1996-10-24

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