US3811765A - Contact-transfer electrostatic printing system - Google Patents

Contact-transfer electrostatic printing system Download PDF

Info

Publication number
US3811765A
US3811765A US00219616A US21961672A US3811765A US 3811765 A US3811765 A US 3811765A US 00219616 A US00219616 A US 00219616A US 21961672 A US21961672 A US 21961672A US 3811765 A US3811765 A US 3811765A
Authority
US
United States
Prior art keywords
liquid
transfer medium
transfer
toner
drum
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Expired - Lifetime
Application number
US00219616A
Other languages
English (en)
Inventor
David Edward Blake
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
Markem Imaje Corp
Original Assignee
Electroprint Inc
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by Electroprint Inc filed Critical Electroprint Inc
Priority to US00219616A priority Critical patent/US3811765A/en
Priority to CA158,599A priority patent/CA998090A/en
Priority to AU50165/72A priority patent/AU481909B2/en
Priority to FR7302023A priority patent/FR2168586B1/fr
Priority to CH88273A priority patent/CH557555A/xx
Priority to NL7300853A priority patent/NL7300853A/xx
Priority to GB296373A priority patent/GB1424128A/en
Priority to IT47786/73A priority patent/IT976963B/it
Priority to DE2302729A priority patent/DE2302729A1/de
Priority to JP48008715A priority patent/JPS4883833A/ja
Application granted granted Critical
Publication of US3811765A publication Critical patent/US3811765A/en
Assigned to MARKEM CORPORATION reassignment MARKEM CORPORATION MERGER (SEE DOCUMENT FOR DETAILS). , EFFECTIVE: DEC. 30, 1986. Assignors: ELECTROPRINT, INC.,
Anticipated expiration legal-status Critical
Expired - Lifetime legal-status Critical Current

Links

Images

Classifications

    • G—PHYSICS
    • G03—PHOTOGRAPHY; CINEMATOGRAPHY; ANALOGOUS TECHNIQUES USING WAVES OTHER THAN OPTICAL WAVES; ELECTROGRAPHY; HOLOGRAPHY
    • G03G—ELECTROGRAPHY; ELECTROPHOTOGRAPHY; MAGNETOGRAPHY
    • G03G15/00—Apparatus for electrographic processes using a charge pattern
    • G03G15/14—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
    • G03G15/1665—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 by introducing the second base in the nip formed by the recording member and at least one transfer member, e.g. in combination with bias or heat
    • G03G15/167—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 by introducing the second base in the nip formed by the recording member and at least one transfer member, e.g. in combination with bias or heat at least one of the recording member or the transfer member being rotatable during the transfer
    • G—PHYSICS
    • G03—PHOTOGRAPHY; CINEMATOGRAPHY; ANALOGOUS TECHNIQUES USING WAVES OTHER THAN OPTICAL WAVES; ELECTROGRAPHY; HOLOGRAPHY
    • G03G—ELECTROGRAPHY; ELECTROPHOTOGRAPHY; MAGNETOGRAPHY
    • G03G15/00—Apparatus for electrographic processes using a charge pattern
    • G03G15/22—Apparatus for electrographic processes using a charge pattern involving the combination of more than one step according to groups G03G13/02 - G03G13/20
    • G03G15/24—Apparatus for electrographic processes using a charge pattern involving the combination of more than one step according to groups G03G13/02 - G03G13/20 whereby at least two steps are performed simultaneously

Definitions

  • a print receiving medium is compressed or pressure biased by means of a roller or other means having a surface preferably resilient against the transfer medium and the compressed print receiving medium and deposited toner particles are contact heated by the pressure roller or means in the transfer area so that toner particles are melted and fixed to the print receiving medium in the configuration of the electrostatic latent image.
  • SHEET 1 OF 2 This invention relates to a new and improved electrostatic printing system and method and in particular to an electrostatic contact transfer printeror copier for I electrostatic printing on plain untreated paper and a variety of other untreated surfaces using liquid toner marking material.
  • the present invention avoids the inherent difficulties in handling, confining, and conveying dry toners and the unreliability of triboelectric dry particle charging due to variation with atmospheric conditions.
  • Liquid toners which utilize a different charging method than dry toner particles, are less subject to changes in ambient conditions.
  • the use of liquid toners in combination with the contact transfer process of the present invention permit direct printing or untreated paper and other surfacesand fixing of toner marking material to the paper, print receiving medium, or other copy surface with much less heat than that required for dry toner particles in conventional electrostatic copiers.
  • the present invention combines the advantages of liquid toner marking material with the capability of printing on untreated, plain paper or any other print receiving medium or substrate.
  • the present invention generally contemplates providing a transfer medium formed with a dielectric surface and means for establishing an electrostatic latent image on the dielectricsurface of the transfer medium.
  • the electrostatic latent image is developed at a developing station which applies to the surface of the transfer medium a liquid toner suspension marking material preferably in the form of toner marking particles suspended in a liquid and the liquid is thereafter removed leaving substantially or nearly dry toner particles on the transfer medium surface in the charge configuration of the electrostatic latent charge image.
  • the invention also contemplates providing a transfer and fixing station at which the developed image on the transfer. medium is transferred under heat and pressure to a print receiving medium or substrate such as paper.
  • the print receiving medium or substrate is compressed or pressure biased against'the surface of the transfer medium at the same time that heat is applied to the print receiving mediumand toner particles so that the toner is melted and fixed to the print receiving medium.
  • the transfer medium is formed in the configuration of a transfer drum formed with an insulative or dielectric outer surface.
  • An imaging station is provided for establishing on the dielectric surface of the drum an electrostatic latent image during rotation of the drum.
  • a liquid face of the roller is maintained at a high temperature sufiicient to melt the toner particles.
  • Thesetceiving medium is fed between the roller and the transfer drum and the roller is compressed or pressure biased against the surface of the drum. The toner markingparticles on the transfer drum. surface are thereby melted and fixed to the transfer medium in the configuration of the electrostatic latent image.
  • the pressure roller need not be formed with a surface of rubber or other elastomeric material and can, in fact, be formed with a solid surface
  • a feature and advantage of the rubber or other elastomer surface is that the elastomer cushions the contact between the hot roller and transfer drum and furthermore, because of the deformation of the elastomer, increases the transfer area and, therefore, the length of time available for melting and transferring the toner particles to the print receiving medium.
  • the increased transfer area and increased time of fixing tends to compensate for any irregularity of the paper or print receiving medium'and the dielectric coated transfer drum. A potenage.
  • an electrostatic charge image configuration is provided by the present invention.
  • an ion corona source such as a line corona source is provided spaced from the transfer drum or other transfer medium surface.
  • the transfer drum is rotated or the transfer medium is translated relative to the actuated line corona source and resultant ion stream whichis directed towardthe transfer medium surface.
  • a twodimensional screen is interposed between the ion source and transfer medium surface and is translated in ductive layer for supporting a double-layer charge electrostatic latent image across the surface of the screen providing fringing fields of force withinthe apertures of the screen of selected orientations and strengths for selectively blocking and enhancing the flow of ions or other charge particles directed through the apertures of the screen from the line corona source.
  • the stream of ions is thereby selectively controlled over a continuous range providing continuous grey-scale control and the ions or other charge particles are thereby selectively deposited on the transfer drum surface or other transof the image to be reproduced.
  • a double layer charge electrostatic latent image can be established on the modulating apertured screen at an optical imaging station by first initially charging the screen to provide a uniform double layer charge on either side of the insulative layer of the screen and thereafter selectively dissipating the charges across the screen in accordance with the relative intensities of an image projected on the screen.
  • the insulative layer of the screen consists of a photoconductive insulating material.
  • a stationary ion flow or charged particle flow screen modulator is interposed between the ion source and transfer medium surface.
  • the stationary modulator consists of a multi-layered bar of an insulative layer with a continuous conductive layer formed on one side and a segmentedconductive layer formed on the other side. At least one row of apertures is formed through the bar so that a segment of the segmented conductive layer substantially surrounds one of the apertures and sothat each aperture is separately electrically addressable through the conductive segments while a selected fixed potential is applied to the continuous conductive layer on the other side for controlling the flow of ionsor other charged particles directed through the apertures of the screen to deposit charges on the dielectric surface of the transfer medium in a desired configuration.
  • a variety of other imaging stations can be provided for establishing an electrostatic latent image directly on the transfer mediumsurface including conventional xerographic imaging stations.
  • the invention further contemplates the provision of unique liquid toners in the electrostatic printing system and method.
  • the invention thus contemplates a liquid toner suspension in which dry xerographic toner particles are suspended in a resistive'carrier fluid.
  • the dry toner particles are of the type consisting of a resin matrix containing pigment particles, dyes and other chemicals. Theseparticles are suspended in the carrier liquid, and various charge control agents can also be added to the suspension to modify the electrophoretic mobility characteristics of the particles.
  • toner particles with average particle size from one micron to thirty microns are used.
  • a suspending liquid that does not appreciably attack or soften the resin matrix of the particles is used, for example, an aliphatic hydrocarbon liquid or a fluorocarbon liquid, and the resin matrix of the toner particles is selected to have a low melting point.
  • FIGS. 1A through 1D diagrammatically illustrate th essential steps of the process contemplatedby the present invention
  • FIG. 2 is a diagrammatic side view of an electrostatic printing system according to the present invention.
  • FIG. 3 is a diagrammatic side view of another electrostatic printing system showing an alternative form of an electrocstatic latent imaging station
  • FIG. 3A is a detailed, fragmentary plan view of the imaging station
  • FIGS. 4 and 4A are a fragmentary, plan view and side cross-sectional view, respectively, of the multilayered bar modulator for modulating the stream of ions originating from a line corona source;
  • FIGS. 5 and 5A are a diagrammatic side view and plan view, respectively, of an alternate electrostatic latent imaging'station using a wire line corona source.
  • FIGS. 1A through D The general system and method contemplated by the present invention for printing on plain, untreated paper or other print receiving medium while maintaining the advantages of using a liquid toner are illustrated diagrammatically in FIGS. 1A through D.
  • the transfer medium in the form of a transfer plate 10 is formed by a base 11 coated with a layer 12 of dielectric material.
  • An electrostatic latent image in the form of a configuration of charges 13 is established on the dielectric layer 12 by conventional xerographic techniques or other electrostatic latent imaging methods specifically contemplated by the present invention and hereinafter more fully described.
  • the charges are illustrated as positive, but may be either positive or negative.
  • the plate 11 is typically metal although any conductive material can be used.
  • the dielectric coating 12 may be of any non-conducting material.
  • the dielectric material is hard and durable with a high dielectric constant, for example, a high PbO-content glass.
  • the latent charge image formed on the dielectric, layer 12 is developed using a special liquid toner consisting of relatively large particles of toner material such as particles. of a resin matrix with carbon black or other colorant in the resin matrix, which'particles are suspended in a non-conductive liquid.
  • a special liquid toner consisting of relatively large particles of toner material such as particles. of a resin matrix with carbon black or other colorant in the resin matrix, which'particles are suspended in a non-conductive liquid.
  • FIG. 18 represents the toning or developing and liquid removal steps showing the solid toner particles 14 retained in position in the configuration of the latent charge image after the removal of the liquid.
  • FIG. 1C represents the transfer step according to which a transfer medium such as a piece of plain, untreated paper 15 is fed or placed in position directly over or adjacent the developed or toned image and a heated roller 16 is rolled across the transfer plate 10 and print receiving medium 15 between which the toner particles 14 of the developed latent charge image are sandwiched.
  • the heated roller 16 rolls under pressure across the sandwich melting the toner and causing it to stick in the fonn of an image 17 to the transfer sheet or other print receiving medium 15. Because heat is transferred from the heated roller through the paper, the toner nearest the paper is completely melted, and flows into and. adheres tenaciously to the paper fibers. Toner particles adjacent to the transfer plate are not melted or are incompletely melted, and therefore do not adhere to the transfer plate.
  • the finished copy bearing the desired toner image 17 which has been transferred and fixed is removed from the transfer plate 11).
  • the dielectric surface 12 of the transfer plate 111 is then cleaned of the small amount of toner particles remaining. Any remaining latent charge is also removed,- for example, by wiping with alcohol or acetone, by exposure to AC corona, or exposure to DC corona of opposite sign to the remaining latent image charge.
  • the transfer plate is then ready for reuse.
  • FIG. 2 A continuous electrostatic printer or copier embodying the system and method of the present invention-is illustrated in FIG. 2.
  • the automatic copying apparatus is in the starting position for a copying or printing cycle with the heated pressure roller 30 withdrawn or disengaged from the transfer drum, and the modulated aperture electrostatic printing screen 42 for electrostatic latent imaging onto the transfer drum 31 is in raised position as hereinafter more fully described.
  • the hot roller 30 can be formed with a rigid solid surface, preferably a layer 32 of rubber or other elastomeric material is provided around the sur face of the drum for cushioning the shock of engagement between the surfaces of the roller 30 and drum 31 and to increase the surface contact area between the roller 30 and drum 31 because of the deformation of the elastomeric layer 32.
  • This increase in surface area contact increases the length of time for melting and transferring toner deposited on the surface of drum 31 onto a print receiving medium sandwiched between the roller and drum.
  • the transfer drum 31 is coated with alayer 33v of dielectric material for retaining a latent image charge configuration established on the dielectric layer at the imaging stationhereinafter more fully described.
  • a release agent such as a silicone can also be applied to the transfer drum surface to improve removability of toner particles and marking material.
  • the heated roller 30 and transfer drum 31' are rotated, respectively, in the direction of the arrows by motors (not shown) so that the surface velocities are identical.
  • an ion corona source 34 is provided for directing a stream of ions toward the dielectric surface 33 of transfer drum 31.
  • a back electrode is provided on the inside of the drum either in the form of a stationary electrode to which a fixed potential is applied or in the form of a conductive inner surface 39 of the drum to which the fixed potential is applied by means of brushes during rotation of the drum.
  • the corona source 34 in this example is formed by a wire 35 parallel with the axis of rotation of the transfer drum to provide a line source of ions and a line stream in the direction of the dielectric surface 33.
  • the ion stream directed towards dielectric surface 33 is selectively modulated during rotation of the drum by means of a two-dimensional multilayered apertured screen 42 which supports a double layer charge electrostatic latent image.
  • the screen 42 includes at least a conductive layer 36 and a photoconductive insulating layer 37.
  • the photoconductive insulating layer 37 is initially uniformly charge over one side by means of, for example, a corona spray.
  • a fixed potential applied to conductive layer 36 results in an equal and opposite charge layer being attracted to the other side of photoconductive insulating layer 37 so that a uniform double layer charge of equal and opposite charges is established across the face of the screen.
  • This initially uniform double layer charge is selectively dissipated or equalized by means of an optical image projected onto the photoconductive layer 37 via lens 40 rendering the photoconductive layer selectively conductive in proportion to the intensity of light striking the layer permitting the charge selectively to leak away through the conductive layer 36 or selectively to equalize with the potential of the conductive layer 36 so that the double layer charge latent electrostatic image configuration is established.
  • a variety of other screen constructions and configurations and other charging and electrostatic latent image forrning arrangements and methods are described in further detail in US. Pat. application, Ser. No. 776,146, entitled Apparatus For Aperture Controlled Electrostatic lmage Reproduction Or Constitution, now US. Pat. No. 3,647,291,-assigned to the assignee of the present case.
  • optical imaging station 38 has been described with reference to the multilayered apertured screen techniques described in the above referenced patent application, conventional xerographic and electrostatic imaging techniques can obviously be used to establish the electrostatic latent image on the dielectric surface 'of drum 31.
  • the screen 42 After the screen 42 has been prepared and imaged, it is transported downward at the same velocity as the dielectric surface 33 of drum 31 as the drum rotates.
  • the ion'projection corona source wire 35 is then energized while the screen passes between the ion source and the drum causing an image-wise charge deposition on the dielectric surface 33.
  • the resulting latent charge image is carried into the development unit 43 where the liquid'toner suspension is deposited on the latent chargeirnage in accordance with well known techniques, and past the air knife 44 where excess toner liquid carrier is blown back into the development unit 43 leaving substantially dry toner particles on drum surface 33.
  • Fresh toner is brought in through inlet 45 and the depleted toner liquid partially depleted of the toner particles carried in the liquid is removed through toner outlet 46 toa tank (not shown) where the liquid is regenerated by addition of more toner particles.
  • the dry or substantially dry toner particles electrostatically adhering to the dielectric surface 33 in the configuration of the image to be transferred is carried toward the hot roller transfer zone 47.
  • the solenoid 50 is actuated which drives the heated roller 30 against a piece of paper 51 previously positioned between the roller 30 and drum 31 on the paper feed chute 52.
  • the elastomeric surface 32 of roller 30 is compressed against the dielectric surface 33 of drum 31 with the paper sandwiched in between and the toner is melted by the heat originating from roller32 and conducted through the paper so that the toner adheres to and is transferred to the paper 51.
  • An electric field can be applied across the transfer drum and roller to assist transfer of marking material to the paper-or other print receiving medium.
  • a copy removal chute 54 is provided for'removing the toned copy paper 51 from the dielectric coated drum 31.
  • Most of the toner applied in development of the elec trostatic latent image is transferred to the copy paper 51 and fused during the transfer process.
  • the small amount of toner remaining on the drum typically less than percent of the initial amount, is not fused and this powdery toner remainder is easily removed by cleaning roller 55.
  • Any charge remaining from the latent charge image on the dielectric surface 33 is removed by the discharging corona 56 so that the dielectric surface 33 is fully prepared for receiving another charge image at the imaging station.
  • a roll of treated fabric can be applied against the drum surface for both charge removal and cleaning.
  • roller 30 While the temperature of roller 30 depends to some extent upon the toner used and the speed of operation of the copier, a roller temperature of between 200F and 600F has been found satisfactory.
  • a pressure between the heated roller 30 and drum 31 of between 2 pounds per lineal inch and 100 pounds per lineal inch can be used in the transfer, the range in pressure depending on the smoothness and heat conductivity of the. paper or-other print receiving medium used.
  • a photoconductive surface for the transfer drum or other transfer medium might'be, for example, amorphous selenium doped with arsenic or tellurium.
  • photoconductive surface With a photoconductive surface, conventional xerographic and electrostatic imaging techniques can be used for directly charging the drum surface.
  • a disadvantage of the use of photoconductive materials for the surface of drum 31, however, is that photoconductors tend to be of soft and fragile materials easily damaged by abrasion and subject to heat damage. Thus, a tough, durable, dielectric coated surface is preferred.
  • the desirable characteristics for the dielectric surface include durability, smoothness, good toner release, and ahigh dielectric constant.
  • a high dielectric constant material accommodates a thicker coating of toner without an initial excessive voltage or potential accumulation in the electrostatic latent image.
  • the image holding forces retaining the toner particles against the transfer surface are increased, reducing any tendency for disruption of the toned image during the liquid removal step.
  • the dielectric constant should not be so high as to interfere in the transfer step.
  • a steel drum can be coated uniformly to a thickness of 42 microns with a high PbO-content glass.
  • the glass is selected with a dielectric constant of 18 yielding a smooth and durable image copy.
  • a substantially linear high velocity jet such as an air knife or other air jet sufficient to remove excess liquid does not disturb the toner particles retained against the transfer surface and the release of toner to the plain paper during transfer and fixing exceeds 95 percent.
  • FIG. 3 A continuous electrostatic printer or copier using another type of electrostatic latent imaging station is illustrated diagrammatically in FIG. 3. Except for the imaging station the printer or copier is essentially the same as that illustrated in FIG. 2 and corresponding elements are numbered the same.
  • the electrostatic latent imaging station 60 incorporated in the system of FIG. 3 is of the type described in US. Pat. application, Ser. No. 864,022 entitled Electrostatic Line Printer, now US. Pat. No. 3,689,935 and assigned to' the assignee of the present case. As shown in FIGS.
  • the latent charge image configuration is established on the dielectric surface 33 of transfer drum 31 by means of a multilayered apertured modulator 61 formed by a central layer 62 of insulative material coated on one side with a substantially continuous conductive layer 63 and on the other side by a segmented layer 64.
  • a row of apertures 65 is formed through the multilayered elements so that each segment 66 of the segmented conductive layer 64 surrounds an aperture 65.
  • Each of the conductive segments 66 of the segmented conductive layer is insulativelyisolated from every other segment and terminates in a terminal 67 for separately electrically addressing the segments of the segmented conductive layer.
  • the multilayered apertures line or bar modulator 61 is aligned adjacent the surface 33 of the transfer drum 31 substantially parallel with the axis of rotation of the drum and a row of point corona sources 68 is provided along the side of the modulator opposite the drum.
  • Each of the point corona sources 68 is substantially in line with one of the apertures 65 and the ion sources 68 direct a line or row stream of ions through the apertures of the line modulator in the direction of the back electrode 39 which may be, for example, the metal base of drum 31.
  • the line or row stream of ions directed through the line or row of apertures of the modulator is selectively modulated in its cross-sectional flow density according to the sequence of selected signals switched and applied to the terminals 67 of the segmented layer.
  • a constant potential is applied to the continuous conductive layer 63 so that fringing fields of force are established within the apertures between the continuous conductive layer 63 and the segment of the segmented conductive layer 64.
  • the lines of force established within the apertures of the bar or line modulator are of selected orientations and 9 strengths for continuous grey-scale control over the latent electrostatic image charge configuration deposited on the dielectric surface 33 of the transfer drum 31.
  • a line corona source such as a corona wire 70 can be used as the source of the ion stream directed through the apertures "65 of the line modulator 61.
  • a variety of related multilayered apertured line or bar modulators applicable for a use in the present invention are set forth in the US. Pat. application, Ser. No. 864,022 referred to above.
  • the main requirement for the toner material used in thesystem and method of the present invention is that the developed toner image be easily and efficiently transferrable to plain paper using conducted heat as described above.
  • Conventional dry xerographic toner material can be used satisfactorily in a completely dry pro- 0.655 in the systems described above, for example, Sun Chemical Corporation Excello toner with a cascade type of development; Addressograph-multigraph Corporation Bruning 2000 toner with a magnetic brush type of developmentyor Sun Chemical Corporation R 415-64 used with a powder cloud type of development.
  • the dry toner materials are deposited on the transfer drum according to the latent charge imagine configuration.
  • the present invention particularly contemplates the use of a novel liquid toner suspension for efficient application in the heating and contact transfer methods and systems described above.
  • conventional liquid electrophoretic toners pigment particles such as carbon black are suspended directly in a liquid carrier along with resin or other polymer particles.
  • the pigment material is generally suspended in the liquid carrier and becomes deposited in particulate form upon evaporation of the liquid after deposition.
  • the piegment particles because of their yery small particle size adhere tenaciously to the dielectric transfer plate and are therefore diflicult to transfer with heat.
  • the conventional liquid toner is relatively unaffected by the application of heat.
  • contact electrostatic transfer of the conventional liquid toner image is possible and has been done, it is subject to the disadvantages of having to contact the paper against wet solvent and solvent vaporization which are avoided by the present invention.
  • a relatively high resin or polymer binder content is provided in the particle material with the resin or polymer content being in the range of approximately -95 percent by weight while the pigment or colorant material content is inthe range of approximately 5-50 percent weight.
  • the particle size should fall in a range from 1 micron to 30 microns in order to permit effective and efficient transfer of particles from the dielectric transfer surface to the print receiving medium. This provides significantly increased transfer capability over conventional liquid toners in which the particle size is typically less than 0.1 micron diameter. While the preferred average particle size is in therange from 1 micron to 30 microns, the particle size distribution can be either narrow (mono-dispersed) or wide (poly-dispersed).
  • the resin or polymer material can be selected with a melting point considerably lower than the 300-350F melting point of conventional dry toners. Thus a melting point as low as 150F can be selected. Because of the low melting point heat fixing and contact transfer can be effected 'at higher speed and at lower temperatures with lower'energy and power or requirements. in conventional xerographic equipment using dry toner particles such a low melting point will result in agglomeration, aggregation and degradation of the dry toner particles during handling by'the mechanical handling equipment. Because there is no mechanical handling of dry toners in the present invention the low melting point resin matrix material is used in the liquid toner suspension without such problems.
  • the particles may also contain charge control chemicals such as, for example 3, S-calcium di-isopropyl salicylate, Versamid 930, or linseed oil.
  • the dry toner particles are suspended in a nonconductive liquid having a resistivity when pure greater than approximately 10 ohm-centimeters.
  • a suitable aliphatic hydrocarbon fluid or fluorocarbon liquid can be used.
  • the composition of the liquid toner suspension is adjusted so that the particles constitute approximately 0.01 percent to 10 percent by weight of the suspension and preferably in the range of 0.5-5 percent.
  • the limitation on the range of relative composition of the suspension as between the particles and liquid carrier at lower concentrations is the length of time to adequately tone the image while at higher- .concentrations of particles the limiting factor is the build-up of dark background in the resultant image.
  • liquid toner suspension marking material arrangements in accordance with the present invention are contemplated.
  • latex-type toner'particles can be suspended in the carrier fluid or liquid.
  • a conventional latex polymer material such as spheres of acrylic plastic of selected color suspended in water is used.
  • the latex polymer material is subjected to hydrocarbon inversion in which the water is removed and the spheres of acrylic plastic suspended in hydrocarbon fluid.
  • Charge control agents such as Versamid 930 are added so that the particles assume desired electrostatic charges.
  • the plastic material of the particles is selected to' have a glass transition temperature to provide desired effects. For example, the glass transition temperature may be selected to be somewhat above or slightly above room temperature.
  • the plastic particles are glass-like and solid.
  • the glass-like particles sus-. pended in the hydrocarbon fluid are applied to the latent charge image on the transfer drum, subjected to the air knife or air jet, and transferred to the paper or other print receiving medium under heat and pressure applied by the roller is heretofore described.
  • With a glass transition temperature slightly above room temperature heating and power requirements for the roller are minimized.
  • the plastic particle material soaks into the paper and upon exposure to the air undergoes curing and cross-linking.
  • the spheres of acrylic plastic or other suitable plastic material are in fluid plastic form, forming liquid or fluid droplets suspended in the hydrocarbon carrier.
  • the liquid toner suspension marking material is thus effectively a liquid emulsion toner.
  • the fluid droplets are independently and selectively charged by charge control agents so that they adhere to the latent charge image while the hydrocarbon fluid carrier is blown off by the air knife or air jet. Heating by the roller is thereby-effectively eliminated in the transfer step and the plastic material cures and undergoes cross-linking upon exposure to the air.
  • the suspended particles in the carrier fluid comprises capsule particles of encapsulated liquid marking material which is released and fixed to the paper or other print receiving medium by the pressure roller.
  • the pressure roller can be used in that event for applying pressure only, or
  • the word particle alone is intended to encompass solid particles, essentially liquid droplets and capsules.
  • a system for electrostatic printing comprising:
  • means for effecting transfer of the developed image from the transfer medium to-a print receiving medium comprising means for pressure biasing a print receiving medium against the surface of the transfer medium and means for heating the print receiving medium and developed image whereby the toner is melted andfixed to the print receiving medium.
  • said means for drying the toner on the medium comprises an air knife and means for supplying said air knife with air substantially saturated with vapors of the liquid toner vehicle.
  • a system for electrostatic printing comprising:
  • a system for electrostatic printing comprising:-
  • a transfer drum formed with an insulative outer surface and means for rotating said drum;
  • an imaging station for establishing on the surface of the drum an electrostatic latent image during rotation of the drum
  • a developing station for applying to an electrostatic latent image formed on the surface of the drum a liquid toner suspension marking material comprising toner marking particles suspended in a nonconductive carrier liquid;
  • a roller formed with a surface of elastomeric material positioned adjacent the transfer drum;
  • said means for removing carrier liquid comprises means for physically separating said carrier liquid from said toner particles.
  • said means for removing carrier liquid comprises a substance which is substantially non-absorptive relative to said carrier liquid and means for thrusting said non-absorptive substance against said carrier liquid on said transfer drum.
  • drum after transfer of a'developed image from the drum surface to a print receiving medium and means for removing any latent charge remaining on the insulative drum surface whereby' the drum surface is prepared for receiving and developing another electrostatic latent image.
  • a system for electrostatic printing as set forth in claim 5,- wherein the imaging station for establishing on the surface of the transfer drum an electrostatic latent image comprises:
  • a multilayered apertured screen including at least an insulative layer and a conductive layer;
  • a multilayered aperture modulator comprising a layer of insulative material having a continuous conductive layer formed on one side thereof and a segmerited conductive layer formed onthe other side, with at least one row of apertures formed through the bar so that each segment of the segmented conductive layer substantially surrounds one of the apertures and so that each aperture is separately electrically addressable through the conductive segments, said multilayered apertured modulator positioned adjacent the surface of the drum and parallel with the drum rotationaxis;
  • a system for electrostatic printing comprising:
  • atransfer medium formed with an insulative outer surface
  • an imaging station for establishing on the surface of the transfer medium, an electrostatic latent image
  • said imaging station comprising a multilayered apertured element including at least an insulative layer and a conductive layer, means for establishing across the apertures, of the element double layer charges providing internal fringing fields within the aperture of the screen of selected orientations and strengths for selectively blocking and enhancing a flow of charged particles directed through theapertures and for'selectively controlling the flow of charge particles over a continuous range in accordance with the charge potentials, means for placing said element in juxtaposition with the transfer medium surface, and means for directing a stream of charged particles through the apertures of the element in the direction of the transfer medium surface whereby the cross sectional flow density of the charged particle stream is modulated in accordance with'the configuration of charges across the apertures of the element whereby the particle flow is deposited on the transfer medium surface to form an electrostatic latent image of the desired configuration;
  • a developing station for applying to an electrostatic latent image formed on thesurface of the transfer medium a liquid toner suspension marking material comprising toner marking particles suspended in a liquid;
  • roller formed with a surface of elastomeric material positioned adjacent the transfer medium;
  • the multilayered aperture element comprises a screen including a conductive layer and a photoconductive insulative layer, and wherein is provided means for establishing across the face of the screen a double layered charge electrostatic latent image comprising means for depositing a substantially uniform charge across the photoconductive insulative layers, means for applying voltage biases to the conductive layer, and means for projecting an image. to be reproduced onto the photoconductive insulating layer.
  • the combifusing means for simultaneously applying heat and pressure to paper at said printing station while said paper is contact applied to said developed image on said transfer medium.
  • a transfer medium formed with a hard, durable, photoinert insulative outer surface
  • imaging means including a multi-layered apertured element having at least an insulative layer and a conductive layer, means for providing layers of charge on opposed surfaces of said insulative layer for establishing fringing fields of selected strengths within the apertures of said element, and means for directing a stream of ions through said apertures in the direction of said transfer medium whereby said ion stream is modulated by said fringing fields to form an electrostatic latent image on said outer surface of said transfer medium;
  • developing means for applying toner marking particles to said electrostatic latent image on said transfer medium to develop such image; printing means for contact applying a sheet of paper or the like to the developed image on said transfer and fusing means for simultaneously applying heat andpressure to paper at said printing station while contact applied to said developed image on said transfer medium.
  • said developing means includes means for applying toner fluid to said electrostatic latent image.
  • liquid removing means comprises a substance-which is substantially non-absorptive relative to said liquid carrier fluid and means for thrusting said non-absorptive substance against said carrier liquid on said transfer medium to separate said liquid from said toner particles.
  • said fusing means includes a heated roller having a deform able surface and means for biasing said roller against paper on said transfer medium.
  • said fusing means includes a heated roller having a deformable surface and means for biasing said roller against paper on said transfer medium.
  • said fusing means includes a heated roller having a deformable surface and means for biasing said roller against paper on'said transfer medium.
  • said fusing means includes a heated roller having a deformable surface and meansfor biasing said roller against paper on said transfer medium.
  • said fusing means includes a heated roller having a deformable surface and means for biasing said roller against paper on said transfer medium.
  • said fusing means includes a heated roller having a deformable surface and means for biasing said roller against paper on said transfer medium.
  • said fusing means includes a heated roller having a deformable surface and means for biasing said roller against paper on said transfer medium.
  • said I fusing means includes a heated roller having a deformable surface and means for biasing said roller against paper on said transfer medium.
  • said fusing means includes a heated roller having a deformable surface and means for biasing said roller against paper on said transfer medium.
  • said fusing means includes a heated roller having a deformable surface and means for biasing said roller against paper on said transfer medium.
  • said fusing means includes a heated roller having a deformable surface and means for biasing said roller against paper on said transfer medium.

Landscapes

  • Physics & Mathematics (AREA)
  • General Physics & Mathematics (AREA)
  • Electrostatic Charge, Transfer And Separation In Electrography (AREA)
  • Liquid Developers In Electrophotography (AREA)
  • Electrophotography Using Other Than Carlson'S Method (AREA)
US00219616A 1972-01-21 1972-01-21 Contact-transfer electrostatic printing system Expired - Lifetime US3811765A (en)

Priority Applications (10)

Application Number Priority Date Filing Date Title
US00219616A US3811765A (en) 1972-01-21 1972-01-21 Contact-transfer electrostatic printing system
CA158,599A CA998090A (en) 1972-01-21 1972-12-11 Contact transfer electrostatic printing system and method
AU50165/72A AU481909B2 (en) 1972-01-21 1972-12-15 Contact transfer electrostatic printing system and method
CH88273A CH557555A (de) 1972-01-21 1973-01-19 Verfahren und vorrichtung zum elektrostatischen drucken mit kontaktuebertragung.
NL7300853A NL7300853A (enrdf_load_stackoverflow) 1972-01-21 1973-01-19
GB296373A GB1424128A (en) 1972-01-21 1973-01-19 Contact transfer electrostatic printing system and method
FR7302023A FR2168586B1 (enrdf_load_stackoverflow) 1972-01-21 1973-01-19
IT47786/73A IT976963B (it) 1972-01-21 1973-01-19 Metodo e dispositivo di stampa elettrostatica a trasferimento e tonificatore per essi
DE2302729A DE2302729A1 (de) 1972-01-21 1973-01-19 Elektrostatisches druck- oder kopiersystem und verfahren
JP48008715A JPS4883833A (enrdf_load_stackoverflow) 1972-01-21 1973-01-22

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
US00219616A US3811765A (en) 1972-01-21 1972-01-21 Contact-transfer electrostatic printing system

Publications (1)

Publication Number Publication Date
US3811765A true US3811765A (en) 1974-05-21

Family

ID=22820008

Family Applications (1)

Application Number Title Priority Date Filing Date
US00219616A Expired - Lifetime US3811765A (en) 1972-01-21 1972-01-21 Contact-transfer electrostatic printing system

Country Status (9)

Country Link
US (1) US3811765A (enrdf_load_stackoverflow)
JP (1) JPS4883833A (enrdf_load_stackoverflow)
CA (1) CA998090A (enrdf_load_stackoverflow)
CH (1) CH557555A (enrdf_load_stackoverflow)
DE (1) DE2302729A1 (enrdf_load_stackoverflow)
FR (1) FR2168586B1 (enrdf_load_stackoverflow)
GB (1) GB1424128A (enrdf_load_stackoverflow)
IT (1) IT976963B (enrdf_load_stackoverflow)
NL (1) NL7300853A (enrdf_load_stackoverflow)

Cited By (15)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3907560A (en) * 1974-03-27 1975-09-23 Addressograph Multigraph Electrophotographic reproduction system utilizing ion modulator and dielectric and dielectric imaging surface
US3937571A (en) * 1974-05-06 1976-02-10 Addressograph-Multigraph Corporation Reproduction system utilizing ion modular and dielectric imaging surface
US3957365A (en) * 1974-07-26 1976-05-18 Addressograph Multigraph Corporation Duplicating apparatus utilizing ion modulating means as the image generating source and method of duplicating therewith
US3972608A (en) * 1973-08-01 1976-08-03 Canon Kabushiki Kaisha Color copying apparatus having one or more screen-like photosensitive members
US4047946A (en) * 1974-07-26 1977-09-13 Addressograph Multigraph Corporation Duplicating process utilizing ion modulating means as the image generating source
US4076403A (en) * 1975-12-11 1978-02-28 Olympus Optical Co., Ltd. Electrographic process
US4135811A (en) * 1977-03-04 1979-01-23 Olympus Optical Company Limited Electrophotographic apparatus
US4181423A (en) * 1973-10-29 1980-01-01 Electroprint, Inc. Electrostatic color printing systems and methods using modulated ion streams
US4284697A (en) * 1975-07-08 1981-08-18 Canon Kabushiki Kaisha Image formation method
US5063413A (en) * 1990-07-31 1991-11-05 Xerox Corporation Removal of excess liquid from an image receptor
US5084735A (en) * 1990-10-25 1992-01-28 Eastman Kodak Company Intermediate transfer method and roller
US5370961A (en) * 1992-12-02 1994-12-06 Eastman Kodak Company Method of electrostatic transferring very small dry toner particles using an intermediate
US5592274A (en) * 1992-01-31 1997-01-07 Fuji Xerox Co., Ltd. Electrophotographic apparatus and process for simultaneously transferring and fixing toner image onto transfer paper
US5870129A (en) * 1995-09-14 1999-02-09 Minolta Co., Ltd. Image forming method and apparatus transferring an ink image
US5965314A (en) * 1997-04-03 1999-10-12 Minnesota Mining And Manufacturing Company Intermediate transfer element for liquid electrophotography

Families Citing this family (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
DE2903265C3 (de) * 1979-01-29 1981-12-24 Siemens AG, 1000 Berlin und 8000 München Vorrichtung zum Transport eines Bildempfangsmaterials durch eine Bildübertragungsstation und zum An-/bzw. Abschwenken des Bildempfangsmaterials an bzw. von einem Zwischenbildträger in der Bildübertragungsstation eines Kopiergerätes oder nichtmechanischen Aufzeichnungsgerätes
DE3136659A1 (de) 1981-09-16 1983-03-24 Hoechst Ag, 6000 Frankfurt Vorrichtung fuer die tonerbilduebertragung

Citations (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3284224A (en) * 1963-01-04 1966-11-08 Xerox Corp Controlled xerographic development
US3647291A (en) * 1968-11-15 1972-03-07 Electroprint Inc Apparatus for aperture controlled electrostatic image reproduction or constitution
US3669706A (en) * 1970-10-19 1972-06-13 Minnesota Mining & Mfg Fusing process and device
US3698314A (en) * 1970-06-15 1972-10-17 Owens Illinois Inc Method for image transfer

Family Cites Families (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3628981A (en) * 1969-06-09 1971-12-21 Seiji Matsumoto Liquid toner development
US3839032A (en) * 1971-06-21 1974-10-01 Savin Business Machines Corp Method of contact transfer of developed electrostatic images

Patent Citations (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3284224A (en) * 1963-01-04 1966-11-08 Xerox Corp Controlled xerographic development
US3647291A (en) * 1968-11-15 1972-03-07 Electroprint Inc Apparatus for aperture controlled electrostatic image reproduction or constitution
US3698314A (en) * 1970-06-15 1972-10-17 Owens Illinois Inc Method for image transfer
US3669706A (en) * 1970-10-19 1972-06-13 Minnesota Mining & Mfg Fusing process and device

Cited By (15)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3972608A (en) * 1973-08-01 1976-08-03 Canon Kabushiki Kaisha Color copying apparatus having one or more screen-like photosensitive members
US4181423A (en) * 1973-10-29 1980-01-01 Electroprint, Inc. Electrostatic color printing systems and methods using modulated ion streams
US3907560A (en) * 1974-03-27 1975-09-23 Addressograph Multigraph Electrophotographic reproduction system utilizing ion modulator and dielectric and dielectric imaging surface
US3937571A (en) * 1974-05-06 1976-02-10 Addressograph-Multigraph Corporation Reproduction system utilizing ion modular and dielectric imaging surface
US3957365A (en) * 1974-07-26 1976-05-18 Addressograph Multigraph Corporation Duplicating apparatus utilizing ion modulating means as the image generating source and method of duplicating therewith
US4047946A (en) * 1974-07-26 1977-09-13 Addressograph Multigraph Corporation Duplicating process utilizing ion modulating means as the image generating source
US4284697A (en) * 1975-07-08 1981-08-18 Canon Kabushiki Kaisha Image formation method
US4076403A (en) * 1975-12-11 1978-02-28 Olympus Optical Co., Ltd. Electrographic process
US4135811A (en) * 1977-03-04 1979-01-23 Olympus Optical Company Limited Electrophotographic apparatus
US5063413A (en) * 1990-07-31 1991-11-05 Xerox Corporation Removal of excess liquid from an image receptor
US5084735A (en) * 1990-10-25 1992-01-28 Eastman Kodak Company Intermediate transfer method and roller
US5592274A (en) * 1992-01-31 1997-01-07 Fuji Xerox Co., Ltd. Electrophotographic apparatus and process for simultaneously transferring and fixing toner image onto transfer paper
US5370961A (en) * 1992-12-02 1994-12-06 Eastman Kodak Company Method of electrostatic transferring very small dry toner particles using an intermediate
US5870129A (en) * 1995-09-14 1999-02-09 Minolta Co., Ltd. Image forming method and apparatus transferring an ink image
US5965314A (en) * 1997-04-03 1999-10-12 Minnesota Mining And Manufacturing Company Intermediate transfer element for liquid electrophotography

Also Published As

Publication number Publication date
JPS4883833A (enrdf_load_stackoverflow) 1973-11-08
FR2168586B1 (enrdf_load_stackoverflow) 1977-02-04
IT976963B (it) 1974-09-10
GB1424128A (en) 1976-02-11
CH557555A (de) 1974-12-31
AU5016572A (en) 1974-06-20
FR2168586A1 (enrdf_load_stackoverflow) 1973-08-31
CA998090A (en) 1976-10-05
NL7300853A (enrdf_load_stackoverflow) 1973-07-24
DE2302729A1 (de) 1973-07-26

Similar Documents

Publication Publication Date Title
US3811765A (en) Contact-transfer electrostatic printing system
US2895847A (en) Electric image development
US3937572A (en) Apparatus for inductive electrophotography
US3084043A (en) Liquid development of electrostatic latent images
US3862848A (en) Transfer of color images
US2924519A (en) Machine and method for reproducing images with photoconductive ink
US3591276A (en) Method and apparatus for offset xerographic reproduction
US3820985A (en) Method and apparatus for inductive electrophotography
US5966570A (en) Image-wise toner layer charging for image development
EP0244199B1 (en) Roll fusing with liquid developer
GB2065509A (en) Liquid-developing latent electrostatic images
US3999481A (en) Method for making a master
US5481341A (en) Roller for controlling application of carrier liquid
US3063859A (en) Method and apparatus for transferring images from xerographic to metallic plates
US3734015A (en) Single pass duplexing by sequential transfer
US4533611A (en) Process for preparing a planographic printing plate
US3806355A (en) Electrostatic printing apparatus and method
US3888664A (en) Electrophotographic printing
GB2075919A (en) Transfering tone and images
US4419004A (en) Method and apparatus for making transparencies electrostatically
US3843381A (en) Transfer process in electrography
US3795530A (en) Electrostatic latent image development
US4216282A (en) AC corona to remove background from the imaging member of a magnetic copier
US3301152A (en) Xerographic copying apparatus
US3672884A (en) Electrostatic printing and developing

Legal Events

Date Code Title Description
STCF Information on status: patent grant

Free format text: PATENTED FILE - (OLD CASE ADDED FOR FILE TRACKING PURPOSES)

AS Assignment

Owner name: MARKEM CORPORATION

Free format text: MERGER;ASSIGNOR:ELECTROPRINT, INC.,;REEL/FRAME:004765/0682

Effective date: 19861231