EP0888222B1 - Procede et appareil destines a rendre une image obtenue par electrocoagulation resistante a l'eau - Google Patents

Procede et appareil destines a rendre une image obtenue par electrocoagulation resistante a l'eau Download PDF

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Publication number
EP0888222B1
EP0888222B1 EP97950434A EP97950434A EP0888222B1 EP 0888222 B1 EP0888222 B1 EP 0888222B1 EP 97950434 A EP97950434 A EP 97950434A EP 97950434 A EP97950434 A EP 97950434A EP 0888222 B1 EP0888222 B1 EP 0888222B1
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EP
European Patent Office
Prior art keywords
ink
positive electrode
dot
crosslinking agent
coagulated
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EP97950434A
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German (de)
English (en)
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EP0888222A1 (fr
Inventor
Adrien Castegnier
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Artience Co Ltd
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Toyo Ink Mfg Co Ltd
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    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B41—PRINTING; LINING MACHINES; TYPEWRITERS; STAMPS
    • B41C—PROCESSES FOR THE MANUFACTURE OR REPRODUCTION OF PRINTING SURFACES
    • B41C1/00—Forme preparation
    • B41C1/10—Forme preparation for lithographic printing; Master sheets for transferring a lithographic image to the forme
    • B41C1/105—Forme preparation for lithographic printing; Master sheets for transferring a lithographic image to the forme by electrocoagulation, by electro-adhesion or by electro-releasing of material, e.g. a liquid from a gel
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B41—PRINTING; LINING MACHINES; TYPEWRITERS; STAMPS
    • B41M—PRINTING, DUPLICATING, MARKING, OR COPYING PROCESSES; COLOUR PRINTING
    • B41M7/00—After-treatment of prints, e.g. heating, irradiating, setting of the ink, protection of the printed stock

Definitions

  • the present invention pertains to a method and an apparatus for electrocoagulation printing. More particularly, the invention relates to an improvement in the field of electrocoagulation printing, which includes tehcnique for rendering an electrocoagulation printed image water-fast.
  • the electrocoagulation printing ink which is injected into the gap defined between the positive and negative electrodes consists essentially of a solution or a dispersion containing an electrolytically coagulable polymer, a liquid medium, a soluble electrolyte and a coloring agent.
  • the coloring agent used is a pigment
  • a dispersing agent is added for uniformly dispersing the pigment into the ink.
  • any remaining non-coagulated ink is removed from the surface of the positive electrode, for example, by scraping the surface with a soft rubber squeegee, so as to fully uncover the colored, coagulated ink which is thereafter transferred onto the substrate.
  • the surface of the positive electrode is thereafter cleaned by means of, for example, a plurality of rotating brushes and a cleaning liquid to remove any residual coagulated ink and oily material adhered to the surface of the positive electrode.
  • the negative and positive electrodes, the oily material coating device, ink injector, rubber squeegee and positive electrode cleaning device are arranged to define a printing unit and several printing units each using a coloring agent of different color are disposed in tandem relation to produce several differently colored images of coagulated ink which are transferred at respective transfer stations onto the substrate in superimposed relation to provide the desired polychromic image.
  • the printing units can be arranged around a single roller adapted to bring the substrate into contact with the dots of colored, coagulated ink produced by each printing unit, and the substrate which is in the form of a continuous web is partially wrapped around the roller and passed through the respective transfer stations for being imprinted with the differently colored images in superimposed relation.
  • the document US-A 4 555 320 discloses an electro-coagulation method of a colloid for reproducing an image which includes the steps of chemically setting or hardening the electro-coagulated colloid.
  • the document EP-A 0 235 700 discloses an electro-coagulation method of a colloid for reproducing an image, wherein the coagulated colloid may be coloured with a dye.
  • the support on which the coagulated colloid may be transferred must be coated with a wetting agent the function of which is to be a good solvent for the dye which, by the solubilizing action of the "wetting agent", is transferred to the wetted support.
  • US-A 4,704,309 discloses a process for printing a substrate with an ink comprising an aqueous system of a colorant and a water dispersible polymer and contacting the ink, after drying, with a solution of one or more multivalent cation salts to impart to the ink a high resistance to water dispersibility.
  • the document WO 96/18507 discloses an electro-coagulation method of a colloid for reproducing an image wherein metal ions generated in excessive and, hence, undesirable amounts from the positive electrode during electrocoagulation printing are "trapped" and thereby prevented from causing undesirable crosslinking of said colloid during the electro-coagulation step.
  • Said sequestering agent has intended effects in the electrifying step (i. e. in the step of coagulating the colloid by applying an electrical current to the electrolytically coagulable ink).
  • EP-A 776 768 discloses an electro-coagulation printing method using a specific record sheet wherein the material ((in)organic substances of claims 9, 18 and 27) effecting a crosslink to the coagulum are applied onto the substrate (record sheet) or even contained in the substrate in advance, i. e. before the coagulum is transferred to the substrate (sheet).
  • the inventor has observed that the colored, coagulated ink which has been transferred onto the substrate is not completely coagulated so that it can be redissolved if water is applied on the substrate. This, of course, is not acceptable for printed material.
  • an electrocoagulation printing method for printing an image on a substrate comprising the steps of:
  • an electrocoagulation printing apparatus for printing an image on a substrate, comprising:
  • the electrocoagulation printing ink contains a coloring agent, an electrolytically coagulable component, a soluble electrolyte, a liquid medium, etc. If the electrocoagulation printing ink is electrified between a positive electrode and a negative electrode, a metallic ion is electrolytically produced from the positive electrode. This metallic ion makes a chemical bond with the electrolytically coagulable component in the printing ink, which causes coagulation, involving the coloring agent, to make a dot of colored and coagulated ink. Namely, the printing ink is electrolytically coagulated by electrifying. Then, by transferring the dots of coagulated ink from the positive electrode onto the substrate so that the transferred dots represent the image, the electrocoagulation printing image is made on a substrate. However, in the presence of water, the dots of coagulated ink on the substrate are often dissolved into the water so that the image on the substrate is damaged.
  • the electrocoagulation printing ink generally contains a polymer as an electrolytically coagulable component, and the polymer makes crosslink with the crosslinking agent applied thereto.
  • Use can be made of inorganic crosslinking agents such as aluminum chloride, aluminum sulfate, chromic acid, chromic chloride, chromic sulfate, chromium potassium sulfate, ferric chloride, ferric sulfate and potassium permanganate.
  • Aluminum chloride and aluminum sulfate are particularly preferred.
  • Use can also be made of an organic crosslinking agent such as formaldehyde.
  • the dots of colored, coagulated ink transferred onto the substrate are treated with the crosslinking agent by applying thereon an aqueous solution or dispersion containing the crosslinking agent.
  • the aqueous liquid is applied in the form of a mist.
  • the crosslinking agent is preferably present in the aqueous liquid in an amount of about 1 to about 2 % by weight, based on the total weight of the liquid.
  • the dots of colored, coagulated ink were treated with the crosslinking agent by wetting the substrate with an aqueous solution or dispersion containing the crosslinking agent and drying the wet substrate prior to the transferring step so that when the dots of colored, coagulated ink were transferred onto the substrate in the transferring step, the crosslinking agent migrated from the substrate into the colored, coagulated ink to crosslink same.
  • the dots of colored, coagulated ink were treated with the crosslinking agent by utilizing as substrate newspaper containing a metallic salt as the the crosslinking agent so that when the dots of colored, coagulated ink were transferred onto the newspaper in the transferring step, the crosslinking agent migrated from the newspaper into the colored, coagulated ink to crosslink same.
  • the metallic salt as the crosslinking agent usually present in newspaper was aluminum sulfate, in said prior art.
  • the electrifying step and the transferring step of the above electrocoagulation printing method are repeated several times to define a corresponding number of printing stages arranged at predetermined locations along the aforesaid path and each using a coloring agent of different color, and to thereby produce several differently colored images of coagulated ink which are transferred at the respective transfer positions onto the substrate in superimposed relation to provide a polychromic image.
  • the positive electrode used can be in the form of a moving endless belt as described in the inventor's US Patent No. 4,661,222, or in the form of a revolving cylinder as described in the aforementioned US Patent No. 4,895,629 or in the inventor's US Patent No. 5,538,601.
  • the printing stages are arranged around the positive cylindrical electrode.
  • the positive electrode active surface and the ink are maintained at a temperature of about 35-60 °C, preferably 35-45 °C, to increase the conductivity of the ink and the release of metal ions from.
  • the positive electrode active surface into the ink in the electrifying step so that the metal ions cause coagulation of the ink and are released in a quantity sufficient to increase the optical density of the coaulated ink, thereby increasing coagulation efficiency in the electrifying step. It is also possible, by heating to the above-described temperature range, to increase the stickiness and hardness of the coagulated ink so that the dots of colored, coagulated ink remain coherent during their transfer in the transferring step, thereby enhancing transfer of the colored, coagulated ink onto the substrate.
  • the positive electrode active surface can be heated at the desired temperature and the ink applied on the heated positive electrode surface to cause a transfer of heat therefrom to the ink.
  • the electrifying step of the above electrocoagulation printing method can be suitably carried out through the steps of:
  • suitable electrolytically inert metals from which the positive and negative electrodes can be made are stainless steel, platinum, chromium, nickel and aluminum.
  • the positive electrode is preferably made of stainless steel, aluminum or tin so that upon electrical energization of the negative electrodes, dissolution of the passive oxide film on such an electrode generates metallic ions, especially multivalent ions, which then cause coagulation of the ink.
  • trivalent ions such as ferric ion and aluminum ion are suitable for causing coagulation of the ink.
  • the gap which is defined between the positive and negative electrodes can range from about 50 ⁇ m to about 100 ⁇ m, the smaller the electrode gap the sharper are the dots of coagulated ink produced. Where the electrode gap is of the order of 50 ⁇ m, the negative electrodes are the preferably spaced from one another by a distance of about 75 ⁇ m.
  • olefinic substances For the oily material which may be used to coat the surface of the positive electrode in the step ii), it is preferred to use olefinic substances.
  • suitable olefinic substances include unsaturated fatty acids such as arachidonic acid, linoleic acid, linolenic acid, oleic acid and palmitoleic acid and unsaturated vegetable oils such as corn oil, linseed oil, olive oil, peanut oil, soybean oil and sunflower oil.
  • a particulaly preferred olefinic substance for composing the oily material mainly contains oleic acid at a ratio of 50 % or more.
  • the olefinic substance may be applied onto the positive electrode active surface in the form of an oily dispersion containing the metal oxide as dispersed phase.
  • suitable metal oxides include aluminum oxide, ceric oxide, chromium oxide, cupric oxide, iron oxide, magnesium oxide, manganese dioxide, titanium dioxide and zinc oxide; chromium oxide is the preferred metal oxide.
  • the amount of metal oxide may range from about 1 to about 50 % by weight, based on the total weight of the dispersion.
  • a particularly preferred dispersion contains about 75 % by weight of oleic acid or linoleic acid and about 25 % by weight of chromium oxide. Operating at a temperature of about 35-60 °C enables one to lower the concentration of metal oxide in the oily dispersion and thus to reduce wear of the positive electrode active surface.
  • the oily material containing the olefinic substance is advantageously applied onto the positive electrode active surface by: providing a distribution roller extending parallel to the positive cylindrical electrode and having a peripheral coating comprising an oxide ceramic material; applying the oily material onto the ceramic coating to form on a surface thereof a film of the oily material uniformly covering the surface of the ceramic coating, the film of oily material breaking down into micro-droplets having substantially uniform size and distribution; and transferring the micro-droplets from the ceramic coating onto the positive electrode active surface. If the oily material completely covers throughout the surface of the positive electrode, the positive electrode is insulated so that electrifying is made substantially impossible. Therefore, the oily material is suitably applied in a form of micro-droplets.
  • a distribution roller having a ceramic coating comprising an oxide ceramic material enables one to form on a surface of such a coating a film of the oily material which uniformly covers the surface of the ceramic coating and thereafter breaks down into micro-droplets having substantially uniform size and distribution.
  • the micro-droplets formed on the surface of the ceramic coating and transferred onto the positive electrode active surface generally have a size ranging from about 1 to about 5 ⁇ m.
  • a particularly preferred oxide ceramic material forming the aforesaid ceramic coating comprises a fused mixture of alumina and titania.
  • a mixture may comprise about 60 to about 90 weight % of alumina and about 10 to about 40 weight % of titania.
  • the oily material is applied onto the ceramic coating by disposing an applicator roller parallel to the distribution roller and in pressure contact engagement therewith to form a first nip, and rotating the applicator roller and the distribution roller in register while feeding the oily material into the first nip, whereby the oily material upon passing through the first nip forms a film uniformly covering the surface of the ceramic coating.
  • the micro-droplets are advantageously transferred from the distribution roller to the positive electrode by disposing a transfer roller parallel to the distribution roller and in contact engagement therewith to form a second nip, positioning the transfer roller in pressure contact engagement with the positive electrode to form a third nip, and rotating the transfer roller and the positive electrode in register for transferring the micro-droplets from the distribution roller to the transfer roller at the second nip and thereafter transferring the micro-droplets from the transfer roller to the positive electrode at the third nip.
  • a transfer roller parallel to the distribution roller and in contact engagement therewith to form a second nip positioning the transfer roller in pressure contact engagement with the positive electrode to form a third nip, and rotating the transfer roller and the positive electrode in register for transferring the micro-droplets from the distribution roller to the transfer roller at the second nip and thereafter transferring the micro-droplets from the transfer roller to the positive electrode at the third nip.
  • the applicator roller and the transfer roller are each provided with a peripheral covering of a resilient material which is resistant to attack by the oily material, such as a synthetic rubber material.
  • a resilient material which is resistant to attack by the oily material, such as a synthetic rubber material.
  • a polyurethane having a Shore A hardness of about 50 to about 70 in the case of the applicator roller, or a Shore A hardness of about 60 to about 80 in the case of the transfer roller.
  • the step ii) of the electrocoagulation printing method of the invention is preferably carried out by providing first and second distribution rollers extending parallel to the positive cylindrical electrode and each having a peripheral coating comprising an oxide ceramic material, applying the oily material onto the ceramic coating of the first distribution roller to form on a surface thereof a film of the oily material uniformly covering the surface of the ceramic coating, the film of oily material at least partially breaking down into micro-droplets having substantially uniform size and distribution, transferring the at least partially broken film from the first distribution roller to the second distribution roller so as to cause the film to substantially completely break on the ceramic coating of the second distribution roller into the desired micro-droplets having substantially uniform size and distribution, and transferring the micro-droplets from the ceramic coating of the second
  • the oily material is applied onto the ceramic coating of the first distribution roller by disposing an applicator roller parallel to the first distribution roller and in pressure contact engagement therewith to form a first nip, and rotating the applicator roller and the first distribution roller in register while feeding the oily material into the first nip, whereby the oily material upon passing through the first nip forms a film uniformly covering the surface of the ceramic coating.
  • the at least partially broken film of oily material is transferred from the first distribution roller to the second distribution roller and the micro-droplets are transferred from the second distribution roller to the positive electrode by disposing a first transfer roller between the first distribution roller and the second distribution roller in parallel relation thereto, positioning the first transfer roller in pressure contact engagement with the first distribution roller to form a second nip and in contact engagement with the second distribution roller to form a third nip, rotating the first distribution roller and the first transfer roller in register for transferring the at least partially broken film from the first distribution roller to the first transfer roller at the second nip, disposing a second transfer roller parallel to the second distribution roller and in pressure contact engagement therewith to form a fourth nip, positioning the second transfer roller in pressure contact engagement with the positive electrode to form a fifth nip, and rotating the second distribution roller, the second transfer roller and the positive electrode in register for transferring the at least partially broken film from the first transfer roller to the second distribution roller at the third nip, then transferring the micro-droplets
  • the oily material-coated positive active surface is preferably polished to increase the adherence of the micro-droplets onto the positive electrode active surface, prior to the step iii).
  • a rotating brush provided with a plurality of radially extending bristles made of horsehair and having extremities contacting the surface of the positive electrode. The friction caused by the bristles contacting the surface upon rotation of the brush has been found to increase the adherence of the micro-droplets onto the positive electrode active surface.
  • the step iii) of the above electrocoagulation printing method is advantageously carried out by continuously discharging the ink onto the positive electrode active surface from a fluid discharge means disposed adjacent the electrode gap at a predetermined height relative to the positive electrode and allowing the ink to flow along the positive electrode active surface, the ink being thus carried by the positive electrode upon rotation thereof to the electrode gap to fill same.
  • excess ink flowing along the positive electrode active surface is collected and the collected ink is recirculated back to the fluid discharge means.
  • the ink generally used advantageously contains, as an electrolytically coagulable component, a linear high molecular weight compound, that is, a polymer having a weight average molecular weight between about 10,000 and about 1,000,000, preferably between 100,000 and 600,000.
  • the electrolytically coagulable compoenent suitably contains a reaction site which includes a functional group selected from the group consisting of an amino group, an amide group and a carboxy group, and which makes a chemical bond with the multivalent metallic ion produced from the positive electrode, especially a trivalent ion such as ferric ion and aluminum ion.
  • suitable polymers for the printing ink include natural polymers such as albumin, gelatin, casein and agar, and synthetic polymers such as polyacrylic acid and polyacrylamide.
  • a particularly preferred polymer is an anionic copolymer of acrylamide and acrylic acid having a weight average moecular weight of about 250,000 and sold by Cyanamid Inc. under the trade mark ACCOSTRENGTH 86.
  • the polymer used can be in a liquid form of either solution or dispersion which includes coloid, etc.
  • the polymer is preferably used in an amount of about 6.5 to about 12 % by weight, and more preferably in an amount of about 7 % by weight, based on the total weight of the ink. Water is preferably used as the medium for dispersing or dissolving the polymer to provide the desired ink.
  • the ink also contains a soluble electrolyte and a coloring agent.
  • Preferred electrolytes include alkali metal halides and alkaline earth metal halides, such as lithium chloride, sodium chloride, potassium chloride and calcium chloride. Potassium chloride is particularly preferred.
  • the electrolyte is preferably used in an amount of about 4.5 to about 6 % by weight, based on the total weight of the ink.
  • the coloring agent can be a dye or a pigment.
  • suitable dyes which may be used for a colored ink are the water soluble dyes available from HOECHST such a Duasyn Acid Black for coloring in black and Duasyn Acid Blue for coloring in cyan, or those available from RIEDEL-DEHAEN such as Anti-Halo Dye Blue T. Pina for coloring in cyan, Anti-Halo Dye AC Magenta Extra V01 Pina for coloring in magenta and Anti-Halo Dye Oxonol Yellow N. Pina for coloring in yellow. When using a pigment as a coloring agent, use can be made of the pigments which are available from CABOT CORP.
  • a dispersing agent is added for uniformly dispersing the pigment into the ink.
  • suitable dispersing agents include the non-ionic dispersing agent sold by ICI Canada Inc. under the trade mark SOLSPERSE 27000.
  • the pigment is preferably used in an amount of about 6.5 to about 12% by weight, and the dispersing agent in an amount of about 0.4 to about 6 % by weight, based on the total weight of the ink.
  • any remaining non-coagulated ink is removed from the positive electrode active surface to separate the coagulated ink from the non-coagulated ink, for example, by scraping the surface with a soft rubber squeegee, so as to fully uncover the colored, coagulated ink.
  • the non-coagulated ink thus removed is collected and mixed with the collected ink, and the collected non-coagulated ink in admixture with the collected ink is recirculated back to the aforesaid fluid discharge means.
  • the optical density of the dots of colored, coagulated ink may be varied by varying the voltage and/or pulse duration of the pulse-modulated signals applied to the negative electrodes.
  • the substrate is in the form of a continuous web which is passed through the respective transfer positions for being imprinted with the colored images at the printing stages.
  • the transferring step is preferably carried out by providing at each transfer position a pressure roller extending parallel to the positive cylindrical electrode and in pressure contact engagement therewith to form a nip and permit the pressure roller to be driven by the positive electrode upon rotation thereof, and guiding the web so as to pass through the nip.
  • the pressure roller is provided with a peripheral covering of a synthetic rubber material such as a polyurethane having a Shore A hardness of about 95.
  • a polyurethane covering with such a hardness has been found to further improve transfer of the colored, coagulated ink from the positive electrode active surface onto the substrate.
  • the pressure exerted between the positive electrode and the pressure-roller preferably ranges from about 4,903 MPa to about 9,806 MPa (50 to about 100 kg/cm 2 ).
  • the positive electrode active surface is generally cleaned to remove therefrom any remaining coagulated ink and oily material.
  • the positive electrode is rotatable in a predetermined direction and any remaining coagulated ink is removed from said positive electrode active surface by providing an elongated rotatable brush extending parallel to the longitudinal axis of the positive electrode, the brush being provided with a plurality of radially extending bristles made of horsehair and having extremities contacting said positive electrode active surface, rotating the brush in a direction opposite to the direction of rotation of the positive electrode so as to cause said bristles to frictionally engage the positive electrode active surface, and directing jets of cleaning liquid under pressure against the positive electrode active surface, from either side of the brush.
  • the positive electrode active surface and the ink are preferably maintained at a temperature of about 35-60 °C by heating the cleaning liquid to thereby heat the positive electrode active surface upon contacting same and applying the ink on the heated positive electrode surface to cause a transfer of heat therefrom to the ink.
  • Fig. 1 which does not show the invention but is given for a better understanding thereof, shows an electrocoagulation printing apparatus.
  • the electrocoagulation printing apparatus 1 comprises a cylindrical positive electrode 3, a negative electrode unit 5, an oil coating unit 7, an ink feeder 9, a remover unit 11, a transfer unit 13 and a crosslinking unit 15A (pre-treatment unit).
  • the cylindrical positive electrode 3 is made of stainless steal and has a continuous passivated surface which defines a positive electrode active surface.
  • the negative electrode unit 5 has a plurality of negative electrodes which are electrically insulated from one another and arranged in rectilinear alignment to define a series of corresponding negative electrode active surfaces disposed in a plane parallel to the longitudinal axis of the positive electrode 3 and spaced from the positive electrode active surface by a constant gap.
  • a plurality of couples of a positive electrode and a negative electrode for forming a plurality of dots of coagulated ink at the same time are constructed.
  • the oil coating unit 7 has an application roller, distribution rollers and transfer rollers which are aligned in pressure contact engagement with each other, and the oily material is applied to the positive electrode 3 through the oil coating unit 7 in a form of micro-droplets, while the positive electrode 3 is rotated in a constant rotating speed.
  • the ink feeder 9 feeds the electrocoagulation printing ink on the positive electrode 3 with the micro-droplets of the oily material.
  • an electrifying device which includes an electric power supply and a controller unit for controlling the power supply, the ink on the positive electrode 3 is electrified with the positive electrode 3 and the negative electrodes of the negative electrode unit 5 in accordance with the image to be printed to form dots of coagulated ink necessary for representing the image.
  • the ink being not coagulated is then removed by scraping with a rubber squeegee of the remover unit 11 and collected for repeated use.
  • the dots of the uncovered coagulated ink on the positive electrode 3 are brought into contact with the substrate S which is continuously transported by a rotating pressure roller of the transfer unit 13, thereby transferred onto the substrate S.
  • an aqueous solution containing the crosslinking agent is sprayed on the substrate S by a sprayer 17 of the crosslinking unit 15A and the wetted substrate S is dried with drier 27. Therefore, when the dots of the coagulated ink are transferred on the substrate S, the crosslinking agent immediately migrates from the substrate S to the dots of the coagulated ink to cause crosslinking reaction to the dots of the coagulated ink, thereby the dots on the substrate are rendered fast to water.
  • the positive electrode 3 is cleaned with the cleaner unit 30 and repeatedly coated with the micro-droplets of the oily material by the oil coating unit 7.
  • Fig. 2 shows another embodiment of a prior art electrocoagulation printing apparatus.
  • the electrocoagulation printing apparatus 19 comprises a crosslinking unit 15B (pre-treatment unit) which has a roll coater 21 for applying the aqueous solution containing the crosslinking agent to the substrate S.
  • the same references as those in Fig. 1 designate the same or similar elements or sections as those of Fig. 1, so description for such elements or sections are omitted here.
  • Fig. 3 shows an embodiment of the electrocoagulation printing apparatus of the present invention.
  • the electrocoagulation printing apparatus 23 comprises a crosslinking unit 15C (post-treatment unit) which includes a nozzle sprayer 25 for spraying the aqueous solution containing the crosslinking agent on the substrate S after the dots of coagulated ink are transferred thereon and a drier 27 for drying the substrate S wet with the aqueous solution containing the crosslinking agent.
  • the same references as those in Fig. 1 designate the same or similar elements or sections as those of Fig. 1.

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  • Chemical & Material Sciences (AREA)
  • Dispersion Chemistry (AREA)
  • Engineering & Computer Science (AREA)
  • Manufacturing & Machinery (AREA)
  • Printing Methods (AREA)
  • Ink Jet Recording Methods And Recording Media Thereof (AREA)
  • Duplication Or Marking (AREA)
  • Ink Jet (AREA)

Claims (13)

  1. Un procédé d'impression par électrocoagulation pour imprimer une image sur un substrat (S), comprenant les étapes de :
    électrification d'une encre qui est électrolytiquement coagulable, en utilisant une électrode positive (3) et une électrode négative (5), et coagulation électrolytique de l'encre entre l'électrode positive (3) et l'électrode négative (5), de manière à former un point d'encre coagulée pour la représentation de l'image ;
    transfert du point d'encre coagulée sur le substrat (S) pour représenter l'image ; et
    traitement des points d'encre coagulée à l'aide d'un agent de réticulation en appliquant une solution ou dispersion aqueuse contenant l'agent de réticulation sur le point d'encre coagulée, de manière à provoquer la réticulation d'un composant réticulable qui est contenu dans l'encre coagulée, de sorte à rendre le point d'encre coagulée résistant à l'eau.
  2. Le procédé selon la revendication 1, dans lequel l'électrode positive (3) est composée d'un matériau métallique qui peut produire électrolytiquement un ion métallique multivalent par électrification et dans lequel l'encre est un liquide électrolytique aqueux contenant un colorant, un électrolyte et un polymère électrolytiquement coagulable contenant un site réactionnel qui peut former une liaison chimique avec un ion métallique multivalent.
  3. Le procédé selon la revendication 1 ou 2, dans lequel l'agent de réticulation comprend un agent de réticulation inorganique qui est choisi dans le groupe se composant de chlorure d'aluminium et de sulfate d'aluminium.
  4. Le procédé selon l'une quelconque des revendications 1 à 3, comprenant en outre, avant l'étape d'électrification, l'étape de : chauffage de l'électrode positive (3) et de l'encre à une température d'environ 35 à 60°C, de sorte à augmenter l'efficacité de coagulation de l'encre.
  5. Le procédé selon la revendication 2, dans lequel le polymère de l'encre a une base moléculaire moyenne en poids de 10 000 à 1 000 000, dans lequel le site réactionnel inclut un groupe fonctionnel qui est choisi dans le groupe consistant en groupe amino, groupe amide et groupe carboxyle, et l'ion métallique multivalent libéré de l'électrode positive (3) comporte un ion trivalent qui est choisi dans le groupe consistant en ion ferrique et ion aluminium.
  6. Un dispositif d'impression par électrocoagulation pour l'impression d'une image sur un substrat (S), comprenant :
    une électrode positive (3) et une électrode négative (5) ;
    un dispositif de mise sous tension électrique pour mettre sous tension électrique une encre qui est électrolytiquement coagulable en utilisant l'électrode positive (3) et l'électrode négative (5) et la coagulation électrolytique de l'encre entre l'électrode positive (3) et l'électrode négative (5), de manière à former un point d'encre coagulée pour représenter l'image ;
    un mécanisme de transfert (13) pour transférer le point d'encre coagulée sur le substrat pour représenter l'image ;
    un dispositif de traitement (15 B) pour appliquer un agent de réticulation sur le point d'encre coagulée après le transfert du point sur le substrat (S), de manière à traiter le point d'encre coagulée à l'aide d'un agent de réticulation afin de provoquer la réticulation d'un constituant réticulable qui est contenu dans l'encre coagulée, de sorte à rendre le point d'encre coagulée résistant à l'eau.
  7. Le dispositif d'impression par électrocoagulation selon la revendication 6, dans lequel l'agent de réticulation à l'aide duquel le dispositif de traitement (15 B) traite le point d'encre coagulée est dissous ou dispersé dans un milieu liquide, et le dispositif d'impression par électrocoagulation comprend en outre un séchoir (27) pour sécher le milieu liquide contenant l'agent de réticulation pour éliminer le milieu liquide, de sorte à fixer l'agent de réticulation sur le substrat (S).
  8. Le dispositif d'impression par électrocoagulation de la revendication 6 ou 7, dans lequel le dispositif de traitement (15 B) comprend un pulvérisateur (25) pour appliquer l'agent de réticulation sous forme de brouillard.
  9. Le dispositif d'impression par électrocoagulation selon la revendication 6, 7 ou 8, dans lequel le dispositif de traitement (15 B) comporte un applicateur à rouleau (21) pour appliquer l'agent de réticulation.
  10. Un produit imprimé, comprenant :
    un substrat (S) ;
    une image représentée sur le substrat comportant au moins un point d'encre qui contient un coagulum d'un polymère électrolytiquement coagulable et un ion métallique multivalent ; et
    un agent de réticulation appliqué sur le point d'encre pour provoquer la réticulation du coagulum.
  11. Le produit imprimé selon la revendication 10, dans lequel le polymère électrolytiquement coagulable contient un site réactif qui forme une liaison chimique avec un ion métallique multivalent.
  12. Le produit imprimé selon les revendications 10 et 11, dans lequel le polymère électrolytiquement coagulable a une masse moléculaire moyenne en poids de 10 000 à 1 000 000, dans lequel le site de réaction comporte un groupe fonctionnel choisi dans le groupe consistant en un groupe amino, un groupe amide et un groupe carboxyle, et l'ion métallique multivalent englobe un ion trivalent qui est choisi dans le groupe consistant en ion ferrique et ion aluminium.
  13. Le produit imprimé selon la revendication 10, 11 ou 12, dans lequel l'agent de réticulation comprend un composé choisi dans le groupe consistant en chlorure d'aluminium et sulfate d'aluminium.
EP97950434A 1996-12-30 1997-12-26 Procede et appareil destines a rendre une image obtenue par electrocoagulation resistante a l'eau Expired - Lifetime EP0888222B1 (fr)

Applications Claiming Priority (3)

Application Number Priority Date Filing Date Title
CA 2194129 CA2194129C (fr) 1996-12-30 1996-12-30 Methode pour rendre indelebile une image imprimee par electrocoagulation
CA2194129 1996-12-30
PCT/JP1997/004902 WO1998029256A1 (fr) 1996-12-30 1997-12-26 Procede et appareil destines a rendre une image obtenue par electrocoagulation resistante a l'eau

Publications (2)

Publication Number Publication Date
EP0888222A1 EP0888222A1 (fr) 1999-01-07
EP0888222B1 true EP0888222B1 (fr) 2002-09-04

Family

ID=4159565

Family Applications (1)

Application Number Title Priority Date Filing Date
EP97950434A Expired - Lifetime EP0888222B1 (fr) 1996-12-30 1997-12-26 Procede et appareil destines a rendre une image obtenue par electrocoagulation resistante a l'eau

Country Status (5)

Country Link
EP (1) EP0888222B1 (fr)
JP (1) JP2000507177A (fr)
CA (1) CA2194129C (fr)
DE (1) DE69715169T2 (fr)
WO (1) WO1998029256A1 (fr)

Family Cites Families (8)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
NL190465A (fr) *
JPS5769054A (en) * 1980-10-17 1982-04-27 Fuji Photo Film Co Ltd Water proofing method of ink jet recording
US4555320A (en) * 1984-05-25 1985-11-26 Elcorsy Inc. Image reproduction by in plane electro-coagulation of a colloid
US4704309A (en) * 1985-06-07 1987-11-03 Eastman Kodak Company Printing processes employing water dispersible inks
CA1279603C (fr) * 1986-02-20 1991-01-29 Adrien Castegnier Impression monochrome et polychrome d'une image reproduite par electrocoagulation d'un colloide
CA2138190C (fr) * 1994-12-15 1998-10-13 Adrien Castegnier Encre d'impression par electrocoagulation stabilisee
US5538601A (en) * 1995-09-14 1996-07-23 Elcorsy Inc. Electrocoagulation printing and apparatus
US5888367A (en) * 1995-11-29 1999-03-30 Tokushu Paper Mfg. Co., Ltd. Record sheet used in electro-coagulation printing method

Also Published As

Publication number Publication date
DE69715169T2 (de) 2003-10-23
EP0888222A1 (fr) 1999-01-07
CA2194129A1 (fr) 1998-06-30
CA2194129C (fr) 2001-02-27
DE69715169D1 (de) 2002-10-10
WO1998029256A1 (fr) 1998-07-09
JP2000507177A (ja) 2000-06-13

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