Card

Abstract: The present invention relates to a method for making heat transfer recordings by forming plural items of imagewise information on the surface of a substrate by a heat transfer technique, a heat transfer sheet as well as cards having greater security against falsifying or counterfeiting.

Description: The present invention relates to a card which is preferably used as an identification card, etc. and provides greater security against counterfeiting and falsifying. Conventionally, many types of cards such as identification cards, driving licences and membership cards carry thereon various items of information to provide a disclosure of what the bearers are. Of the most importance for ID cards in particular are literal information such as name and address and a photographic image of face. One classical technique for applying a photograph of face to each of various cards involves bonding it to a given region of the card with an adhesive. Problems with this technique are that it is very laborious; it makes the surface of the card uneven and so rids it of flatness; and it allows the card to be easily counterfeited or falsified by the replacement of another photograph of face. In order to solve the defect of such an old technique as mentioned above, there has been developed a sublimation transfer type of imaging technique. According to this heat transfer technique, a sublimation type of heat transfer sheet formed by providing onto the surface of a substrate film a layer containing a dye sublimable and transferable by heat is overlaid on a card substrate, and the assembly is heated from the back side of the sublimation transfer sheet with a thermal heat to reproduce a photograph of face on the card substrate simultaneously with printing of various letters, characters and so on. Alternatively, these characters may be printed in a hot meltable ink type of heat transfer manner. In either case, this technique has the advantage of being able to be carried out with a simple thermal printer. Since various items of information obtained by the above heat transfer technique are less than satisfactory in terms of such properties as rub resistance, however, the surface of the photograph, etc. is generally provided with a transparent surface protecting layer excelling in such properties as rub resistance. Especially because the photograph is formed by fixing the dye in the card substrate, the card obtained by the above technique is of improved flatness and provides greater security against falsifying and counterfeiting. Even with this technique, however, there is not a little fear that the photograph and other information may be falsified or counterfeited by removing the protecting layer by solvents, acids, bases or the like. EP 0 273 347 A2 describes a thermal print element comprising a support having thereon a layer containing a thermally-transferred dye image, the element having at least one layer of adhesive thereon comprising a linear, random copolyester of one or more aromatic dibasic acids and one or more aliphatic diols, modified with up to 30 mole % of one or more aliphatic dibasic acids. EP 0 279 467 A2 describes a heat transfer sheet to be used for heat-sensitive transfer. EP 0 270 677 A1 describes a thermal transfer sheet for forming color image, which comprises a base sheet having provided thereon a dye carrying layer having the hues of cyan, magenta, and yellow. EP 0 257 633 A1 describes a heat transfer printer, a heat transfer process and a heat transfer ink sheet. EP 0 203 056 A2 describes a closed loop thermal transfer recording system and color transfer ribbon having a plurality of different color ink stripes thereon being provided for recording a color tonal image on a recording sheet. Patent abstracts of Japan, publication no. 57015997, describes a heat-sensitive color forming layer provided on the face side of the support member, and a heat-sublimable or hot-melting ink layer provided on the back side of the support member through a heat conductive layer to obtain a thermal recording medium. Patent abstracts of Japan, publication no. 62153993, describes a hologram transfer sheet with a pattern in which the pattern and hologram are constituted in a single body, formed by the constitution to laminate successively a separating protecting layer, a pattern layer, a hologram layer, a reflecting thin film layer and an adhesive layer on a supporting body. It is accordingly an object of the present invention to provide a card to which greater security against counterfeiting and falsifying is imparted. This object is attainable by the card as defined in claim 1 of the present invention. More specifically, the present invention relates to. a card comprising a card substrate including a heat transferred image (48), a laminated film (41) including a holographic image (42), laminated on the card substrate through an adhesive layer (43), and a surface protecting film (49) provided on the surface of the laminated film (41). The card substrate used for the card of the present invention may be formed of any known material. For instance, use may be made of films or sheets of various plastics such as polyolefin, polyvinyl chloride, polyethylene terephthalate, polystyrene, polymethacrylate and polycarbonate. Use may also be made of white, opaque films or foamed sheets obtained from such synthetic resins to which white pigments and fillers are added. Use may further be made of synthetic paper (based on polyolefin, polystyrene, etc.), fine paper, art or coated paper, cast coated paper, wall paper, lining paper, synthetic resin or emulsion-impregnated paper, synthetic rubber latex-impregnated paper, synthetic resin-incorporated paper, paperboard, cellulose fiber paper or the like. Still further, laminates comprising any desired combination of the above substrate films may be used to this end. This aspect of this invention is directed to a laminated film for protecting the surface of a heat transfer image, characterized in that said film includes a holographic image on at least its part and an adhesive layer on its one side. The laminated film is provided on at least its part with a holographic image and on its one side with an adhesive layer, and is then laminated on the surface of a heat transfer image, whereby an improved durability is imparted to the transfer printed image together with much fairer appearance and a peculiarity or designability. Use of this laminated film for making ID cards or other certificates in particular provides greater security against counterfeiting or falsifying, since the holographic image can hardly be prepared by simple equipment or small entities. Figure 25 is a sectional illustration of one embodiment of the laminated film according to this aspect of this invention, which is characterized in that an adhesive layer 43 is formed on one major surface of a transparent laminated film 41 including a holographic image 42. Through the adhesive layer 43, the laminated film according to this aspect of the invention is laminated on the imagewise surface of a heat transfer image sheet 47 including a heat transfer image 48, as shown in Figure 26, whereby the service life of the printed image can be improved greatly. In addition, the heat transfer image 48 can be viewed from the laminated side simultaneously with the holographic image 42, as sketched in Fig. 27, with the result that the appearance, designability and peculiarity are improved as a whole. In the embodiment described with reference to Figs. 25-27, the holographic image 41 is provided on a part of the laminated film 41. In this case, the holographic image 42 may be of either the transparent type or the reflection type, and so is not critical. When using the reflection type of holographic image, however, it is required that the holographic image be not superposed on the underlying heat transfer image, because the underlying heat transfer image cannot be viewed when such superposition takes place. Figures 28 and 29 are illustrations of another preferable embodiment of this aspect of this invention. This embodiment is basically identical with the embodiment shown in Figs. 25-27, provided that a holographic image 42 of the transparent or semi-transparent type is placed all over the surface of a limited film 41. Through an adhesive layer 43, this laminated film is laminated on the imagewise surface of a heat transfer image sheet 47 including a heat transfer image 48, as is the case with the above first embodiment, whereby the heat transfer image 48 can be viewed from the laminated side simultaneously with the holographic image 42, with the result that the appearance, designability and peculiarity are improved as a whole. This embodiment is particularly preferred because of the appearance, designability and peculiarity being further improved. This is because, owing to its transparency or semitransparency, the holographic image 42 may be superposed on the underlying heat transfer image 48. Moreover, the laminated film 41 may be provided on its surface with a surface protecting film 49 of resin whose harded is increased. Figure 30 is an illustration of yet another embodiment of this aspect of this invention, in which a release layer 40 is interposed between a laminated film 41 and a holographic image 42. As is the case with the above second embodiment, the laminated film is removed after lamination. In this case, therefore, the holographic image 42 serves as a sort of laminated film. The laminated film 41 used according to this aspect of this invention may be of transparency sufficient to allow the underyling heat transfer image 48 to be viewed through it, and may be colored or matted. The most preference to this end is given to films of polyethylene terephthalate, polycarbonate, polyamide and the like. In consideration of transparency, mechanical strength, heat resistance and other factors, the polyethylene terephthalate film is optimum. Although not critical, the holographic image 42 used according to this aspect of this invention may be a holographic image of the transparent, semi-transparent or opaque (reflection) type heretofore known in the art. Such a hologram image per se is well-known in the art, as set forth in greater detail in a number of specifications of our prior applications directed to the production and exploitation of holograms or in Takeuchi, "Printing Information", No. 3, pp. 17-24 (1986). Particularly preferred in this aspect of this invention is a relief hologram. The relief hologram is three-dimensionally reproducible either by white light such as daylight or illumination light or by specific reproduction light such as a laser beam. One type of holographic image, reproduced by white light such as daylight or illumination light, has an improved ornamental effect, since it can be viewed even in a normal state. Another type of holographic image, reproducible by a laser beam, makes it easier to detect forging or counterfeiting. The relief hologram will now be explained with reference to Fig. 28. The relief hologram is constructed from a support layer 42 (corresponding to the laminated film 41 in this aspect), a hologram forming layer 45 and a holographic effect layer 44 laminated together in that order. In order to make such a hologram sheet, the support film 42 such as a polyethylene terephthalate film is first provided on its surface with a layer of resin which is solid at normal temperature and capable of being thermally formed, for instance, a layer 45 (a hologram forming layer) of resin which is solid at normal temperature, thermoplastic and capable of being cured upon exposure to ionizing radiations. Then, a holographic plate (not shown) having thereon an irregular holographic interference pattern is pressed against the surface of the layer 45 to transfer that irregular pattern, shown at 46, onto it, followed by curing. Finally, the thus transferred layer is provided on its surface, now patterned, with the holographic effect layer 44 formed of a thin film (e.g., an aluminized thin film) of material which combines sufficient transparency with high reflecting properties at a certain angle and is different in the index refraction from the hologram forming layer 45. Thus, the hologram sheet may be formed in conventional known materials. With such a hologram sheet appearing to be transparent or semi-transparent as a whole, the holographic image can be viewed by reflected light through the holographic effect layer 44 or even by transmitted light because of the holographic effect layer 44 being nearly transparent. As a matter of course, this hologram sheet would be made entirely transparent in the absence of that holographic effect layer. If the holographic effect layer is made of an opaque and reflecting metal or the like, then the opaque (reflection) type of relief hologram is obtained. Although not critical, this hologram sheet may generally have a thickness lying between about 10 µm and about 300 µm. The adhesive layer 43 formed on the surface of the holographic image 42 may be made of either a heat-sensitive adhesive which is softened by heating to show adhesion or a pressure-sensitive adhesive which shows adhesion upon pressurized. Such heat- and pressure-sensitive adhesives are all well-known in the art and may be used as such for this aspect of this invention. The adhesive layer, for instance, may have a thickness of about 5 to 50 µm. When the adhesive layer is formed of a pressure-sensitive adhesive, a release paper (not shown) may be applied on its surface. On the other hand, the object on which the laminated film according to this aspect of this invention is to be laminated includes a heat transfer image, and how to heat-transfer the heat transfer image is known in the art as well. Heat transfer techniques using a meltable type of heat transfer sheet including a pigment-containing wax layer on the surface of a substrate film or a sublimation type of heat transfer sheet having a substrate film provided on its surface with a dye layer carried with a thermally displaceable dye by means of a binder may all be usable according to the sixth aspect of this invention. Effectively usable for the sublimation type of heat transfer sheet are any dyes employed for conventional known heat transfer sheets. By way of example alone, mention is preferably made of red dyes such as MS Red G, Macrolex® Red Violet R, Ceres® Red 7B, Samaron® Red HBSL, SK (Rubin) SEGL, (Bimicron) SN VP 2670 and Resolin® Red F3BS; yellow dyes such as (Phorone®) Brilliant Yellow S-6GL, PTY-52, Macrolex® Yellow 6G and (Terasil®) Golden Yellow 2RS; and blue dyes such as (Kayaset) Blue 714, (Vacsolin®) Blue AP-FW, (Phorone®) Brilliant Blue S-R, MS Blue 100 and (Dito®) Blue No. 1. The heat transfer image receiving sheet used for forming the heat transfer sheet may be known in the art as well, and may be formed of paper, plastic sheets, card substrates and like materials. Referring to one sublimation type of heat transfer image receiving sheet by way of example, this image receiving sheet includes a suitable substrate film on which a dye receiving layer is formed. Usable to this end are any materials heretofore used for the dye receiving layers of conventional sheets to be heat-transferred. The materials, for instance, may be one of the following (a) to (e) or a mixture of two or more thereof. (a) Materials having ester linkages polyester, polyacrylic ester, polycarbonate, polyvinyl acetate, styrene acrylate resin, vinyltoluene acrylate resin, etc. (b) Materials having urethane linkages polyurethane, etc. (c) Materials having amide linkages polyamide such as nylon, etc. (d) Materials having urea linkages urea resin, etc. (c) Materials having other linkages of high polarity polycaprolactam, polystyrene, polyvinyl chloride, polyacrylonitrile, etc. The dye receiving layer may also be formed of a mixed resin of an saturated polyester with a vinyl chloride/vinyl acetate copolymer. In this case, it is preferable that the vinyl chloride/vinyl acetate copolymer has a vinyl chloride content of 85-97 % by weight and a polymerization degree of about 200-800. The vinyl chloride/vinyl acetate copolymer may also contain such components as vinyl alcohol and maleic acid. In addition, the dye receiving layer may be comprised of styrene type resins other than the above-mentioned polystyrene. The styrene type resins, for instance, may include homo- or co-polymers of styrene type monomers such as styrene, α-methylstyrene and vinyltoluene; and copolymers of such styrene type monomers with other monomers, e.g., acrylic or methacrylic monomers such as acrylic acid ester, methacrylic acid ester, acrylonitrile and methacrylonitrile and monomers based on maleic anhydride and vinyl chloride/acrylic acid. If required, ultraviolet absorbers may be incorporated into the above-mentioned dye receiving layer, thereby improving the weather resistance of the dye coming from the heat transfer sheet and fixed to the dye receiving layer. The ultraviolet absorbers used may be those based on benzophenone, hindered amines, benzotriazole and so on, and may be used in an amount of about 0.05 to 5 parts by weight per 100 parts by weight of the resin forming the dye receiving layer. If required, the above-mentioned dye receiving layer may further contain a release agent with a view to improving its releasability with respect to the heat transfer sheet. The release agents used, for instance, may include solid waxes such as polyethylene wax, amide wax and Teflon powders, surface active agents based on fluorine and phosphoric acid or silicone oil, but preference is given to silicone oil. The silicone oil used may be in oily form, but should preferably be of the curing types, i.e., the reactive, photo- and catalytic curing types. The most preference is given to the reactive curing type of silicone oil. As the reactive curing type of silicone, use should preferably be made of one obtained by the reaction of an amino-modified silicone oil with an epoxy-modified silicone oil. The curing type of silicone oil should preferably be used in an amount of 0.5 to 30 parts by weight of 100 parts by weight of the resin forming the dye receiving layer. In addition to being incorporated into the dye receiving layer, the release agent may be dissolved or dispersed in. a suitable solvent. The resulting solution may then be applied and dried on the surface of the dye receiving layer, thereby forming a release layer. As the release agent forming the release layer, particular preference is given to a cured product obtained by the reaction of an amino-modified silicone oil with an epoxy-modified silicone oil, as mentioned just above. Preferably, the release layer should be formed to a thickness of 0.01 to 5 µm, particularly 0.05 to 2 µm. The release layer may be applied all over the surface of the dye receiving layer or on a part thereof. When the release layer is formed on a part of the dye receiving layer, the sublimation heat transfer recording technique may be used in combination with other recording techniques. For instance, sublimation transfer recording may be applied to one part of the dye receiving layer on which the release layer is provided, while dot impact recording, thermal melting transfer recording, recording with a pencil or other recording is applied to another part of the dye receiving layer, on which no release layer is provided. This aspect of this invention, described with reference to its preferred embodiments, is useful for the lamination of films having various heat transfer images. For instance, the laminated film according to this aspect of the invention is equally applicable to various cards certifying the bearers' nationalities or citizenships, addresses, dates of birth, places of employment, duties and authorities such as student's cards, ID cards issued by private enterprises and public agencies and membership cards issued by various clubs as well as various ID cards heretofore available. It is understood, however, that this invention is not limited to such identification cards. For instance, this invention may be useful to prepare various prints having an increased ornamental effect. According to this aspect of the invention, the laminated film, on which the.holographic image is formed locally and the adhesive layer is provided on its one side, is laminated on the imagewise surface of the heat transfer image, whereby an excellent durability can be imparted to the transfer-printed image together with much more improved appearance, peculiarity and designability. Especially when this laminated film is used to prepare ID cards or other certificates, it is possible to provide greater security against counterfeiting or falsifying, since it is difficult for small entities to make the holographic image with simple machinery. The present invention will now be explained more illustratively with reference to the following examples, in which all parts and percentages (%) are by weight unless otherwise indicated. Example A solution of an ethylene/vinyl acetate copolymer was coated and dried on the surface of a transparent type of rainbow hologram sheet commercialized by Dai Nippon Printing Co., Ltd. (of A3-size and 50 µm in thickness) to form an adhesive layer of about 20 µm in thickness, thereby obtaining a laminated film according to this invention. On the other hand, a sublimation type of heat transfer sheet of three colors, yellow, magenta and cyan, was overlaid on a substrate sheet of a hard vinyl chloride resin including a dye receiving layer on its surface, while the dye layer was located in opposition to the dye receiving layer. With a thermal sublimation transfer printer (VY-50 commercialized by Hitachi,.Ltd.), a printing energy of 90 mJ/mm 2 was applied through its thermal head to the assembly from the back side of the heat transfer sheet for successive heat transfer, thereby recording full-colored photographs of face, signatures, dates of birth, addresses, names of employers, etc. for six individuals. The laminated film was then thermally applied to the imagewise surface, which was in turn cut into six parts to prepare six ID cards. A full-faced viewing of each certification card gives no holographic image, but provides a clear indication of the heat-transferred image. A viewing of the card at an angle of about 45° gave a clear holographic stereogram. A forced removal of the hologram sheet destroyed partly the dye receiving layer that was the image carrier, leaving one piece of the image on the substrate sheet and another piece on the hologram sheet. It was virtually impossible to falsify the photographs, etc.

Claims: A card comprising a card substrate including a heat transferred image (48), a laminated film (41) including a holographic image (42), laminated on the card substrate through an adhesive layer (43), and a surface protecting film (49) provided on the surface of the laminated film (41).

Inventors: ANDO JITSUHIKO, FUJIMURA HIDEO, IWATA TAMAMI, OSHIMA KATSUYUKI, TORII MASANORI, YAMAUCHI MINEO, ANDO, JITSUHIKO, FUJIMURA, HIDEO, IWATA, TAMAMI, OSHIMA, KATSUYUKI, TORII, MASANORI, YAMAUCHI, MINEO, Ando, Jitsuhiko, Dai Nippon Insatu K.K., Fujimura, Hideo, Dai Nippon Insatu K.K., Iwata, Tamami, Dai Nippon Insatu K.K., Oshima, Katsuyuki, Dai Nippon Insatu K.K., Torii, Masanori, Dai Nippon Insatu K.K., Yamauchi, Mineo, Dai Nippon Insatu K.K.
Applicants: DAINIPPON PRINTING CO LTD, DAI NIPPON INSATSU KABUSHIKI KAISHA
Application year: 1990
Main classification: B42D15
IPC codes: B41M5, B41M7, B42D15, B41M3, B32B38, G03H1, G02B5