JP2004299278A - Printing method and image forming body using thermal diffusion transfer and dye receiving layer - Google Patents

Abstract

The present invention provides a printing method and an image forming body capable of forming a complete latent image with no change in the density of a visible dye image and no unevenness of the latent image and suppressing a decrease in fluorescence intensity.
A first step of forming an image with a visible dye by thermal diffusion transfer, a second step of transferring a dye receiving layer onto the image, and a latent dye of fluorescent dye on the dye receiving layer by thermal diffusion transfer. A third step of forming an image image.
[Selection diagram] FIG.

Description

この表に示すように、イエロー染料のみを転写した場合と比較して、本発明のイエロー染料転写後に染料受容層を転写し、その後蛍光染料を転写したものは、イエローの濃度低下が見られなかったが、従来のイエロー染料転写後に染料受容層なしに蛍光染料を転写したものは、バックトラップの影響によりイエローの濃度の低下がみられた。また、本発明のイエロー染料転写後に染料受容層を転写し、その後蛍光染料を転写したものは、従来のイエロー染料転写後に染料受容層なしに蛍光染料を転写したものに比べて蛍光強度の低下が抑制された。
【００５１】
例２
上記例１で得られた本発明の画像形成体にさらに保護層を設けた。
保護層は、以下の表に示す材料を用いグラビアコートにより形成した。乾燥後の膜は１ｇ／ｍ^２であった。
・塩化ビニル酢酸ビニル共重合樹脂 ３０重量部
（ユニオンカーバイト社製ＶＹ−ＬＦＸ）
・トルエン ３５重量部
・メチルエチルケトン ３５重量部
保護層を設けることで、より不可視性の高い画像形成体が得られた。
【００５２】
【発明の効果】
本発明においては、可視染料の転写後に、染料受容層を転写することにより、蛍光染料転写時のバックトラップによる画像の濃度低下を抑制することができ、かつそこに蛍光染料を熱拡散転写して潜像画像を設けることにより、画像の凹凸もなく、また可視染料と共存することによる蛍光の消光もない潜像画像を形成することができる。
【図面の簡単な説明】
【図１】図１は、熱溶融転写を用いた印画方法の従来技術を説明する図である。
【図２】図２は、熱拡散転写を用いた印画方法の従来技術を説明する図である。
【図３】図３は、本発明の熱拡散転写と染料受容層を用いた印画方法の一例を説明する図である。
【符号の説明】
１１、２１，３１ 受像紙
１２、２２、３２ イエロー染料
１３、２３、３３ マゼンタ染料
１４、２４、３４ シアン染料
１５、２５、３５ 蛍光染料
１６ 保護層
２７ 蛍光染料インクリボン
２８ 可視染料移行部位
３９ 染料受容層[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to an image forming body having a latent image which cannot be recognized under normal visible light, but can be visually recognized in a fluorescent color by irradiating ultraviolet light or the like other than visible light, and a printing method therefor. Preferably, the present invention relates to a heat transfer sheet, a material which can be used for a security element.
[0002]
[Prior art]
An image using both a visible dye and a fluorescent dye has been conventionally used as an image having security such as copy protection. As a technique for producing such a print, an image is formed by thermal diffusion transfer of a visible dye such as a yellow dye, a magenta dye, or a cyan dye, and then a fluorescent color material that emits visible light by ultraviolet irradiation is thermally melt-transferred or formed. A method of forming a latent image by thermal diffusion transfer is known.
[0003]
However, when the latent image was formed by hot-melt transfer, although the image was colorless, the image had irregularities, so that the irregularities could be visually recognized without irradiating ultraviolet rays, and the image was not a complete latent image. Further, even when a protective layer is provided so as to cover the surface of the latent image, unevenness of the image may be visible in some cases, and it has been difficult to obtain a complete latent image.
[0004]
FIG. 1 is a view for explaining a conventional technique based on such thermal fusion transfer. When the fluorescent dye 15 is thermally melt-transferred onto the image receiving paper 11 to which the yellow dye 12, the magenta dye 13 and the cyan dye 14 have been transferred, the fluorescent dye 15 swells.
[0005]
On the other hand, when the latent image is provided by the thermal diffusion transfer, the visible dye is transferred to the fluorescent dye ink sheet by heating at the time of transferring the fluorescent dye, although there is no unevenness of the image. When the latent image is provided, the color of the visible dye image in the portion where the latent image is provided is partially lightened, the pattern of the latent image may be visible, and when the visible dye and the fluorescent dye coexist. In some cases, the fluorescence of the fluorescent dye is weakened or lost due to a phenomenon such as energy transfer between the dyes.
[0006]
FIG. 2 is a view for explaining a conventional technique based on such thermal diffusion transfer, in which a visible dye is transferred to a fluorescent dye ink ribbon 27 as shown by a visible dye transfer portion 28 by heating during transfer of the fluorescent dye. . When the yellow dye 22, the magenta dye 23, the cyan dye 24, and the fluorescent dye 25 are sequentially transferred onto the image receiving paper 21, the layer 25 to which the fluorescent dye has been transferred already contains the yellow dye, the magenta dye, and the cyan dye. Therefore, these visible dyes act on the fluorescent dye, and the fluorescence of the fluorescent dye is weakened.
[0007]
[Patent Document 1]
JP 2003-1935 A [Patent Document 2]
JP 2003-25736 A [Patent Document 3]
JP 2000-168243 A [Patent Document 4]
Patent No. 3123001 [0008]
[Problems to be solved by the invention]
The problem to be solved by the present invention is to solve the above-mentioned problem, that is, to form a complete latent image without a change in the density of the image of the visible dye and unevenness of the latent image, and suppressing a decrease in the fluorescence intensity. It is another object of the present invention to provide a printing method and an image forming body that can perform the printing.
[0009]
[Means for Solving the Problems]
In order to achieve the above object, the printing method of the present invention comprises a first step of forming an image with a visible dye by thermal diffusion transfer, a second step of transferring a dye receiving layer onto the image, and the dye receiving layer. A third step of forming a latent image of a fluorescent dye by thermal diffusion transfer thereon.
[0010]
Further, the image forming body of the present invention is provided with a dye receiving layer on a visible dye image formed by thermal diffusion transfer, and a latent image of a fluorescent dye formed by thermal diffusion transfer on the dye receiving layer. It is characterized by becoming.
[0011]
In a preferred embodiment of the present invention, the visible dye is a dye selected from a yellow dye, a magenta dye and a cyan dye, and a protective layer may be further formed on the latent image.
[0012]
In a preferred embodiment of the present invention, there is provided a security element having the above-mentioned image forming body.
[0013]
In addition, the visible dye layer / dye receiving layer forming layer / fluorescent dye layer integrated type thermal diffusion transfer sheet of the present invention is formed on one surface of the base sheet so as to perform thermal diffusion transfer in the order of visible dye, dye receiving layer and fluorescent dye. In addition, a visible dye layer, a dye receiving layer forming layer, and a fluorescent dye layer are provided side by side.
[0014]
BEST MODE FOR CARRYING OUT THE INVENTION
FIG. 3 is a diagram illustrating an example of a printing method using thermal diffusion transfer and a dye receiving layer, in which a yellow dye 32, a magenta dye 33, and a cyan dye 34 are transferred onto an image receiving paper 31, and thereafter, The dye receiving layer 39 is transferred, and the fluorescent dye 35 is further transferred onto the dye receiving layer by thermal diffusion transfer. With this configuration, since the thermal diffusion transfer is used, the latent image formed by the fluorescent dye can be made uneven. Further, since the dye receiving layer 39 is interposed therebetween, the visible dye is not trapped during the transfer of the fluorescent dye, and the density of the visible image does not decrease, so that the invisibility of the latent image can be increased. Further, since the visible dye and the fluorescent dye are present in different layers, a decrease in the fluorescence intensity can be suppressed.
[0015]
Thermal diffusion transfer In the present invention, an image is formed by thermal diffusion transfer. This thermal diffusion transfer is a transfer method also called diffusion transfer or sublimation transfer. Typically, the dye layer of the thermal diffusion transfer sheet is overlapped so as to face the image forming area of the screen to be printed, and the dye layer is Heating is performed in accordance with image information to be printed so that the dye is thermally diffused into the image forming area of the screen to be printed.
[0016]
The transfer amount of the dye can be arbitrarily adjusted by changing the heating energy, and when a combination of dyes of different colors is used, various stepless tones including white can be arbitrarily created. Further, in the transfer, any of the dot matrix method and the overlap printing can be performed.
[0017]
By using such a thermal diffusion transfer system, unevenness does not occur, the invisibility of the fluorescent dye is excellent, and it is possible to make it hard to find that the image is printed using the fluorescent dye. Further, unlike other transfer methods, a laminated structure in which the dye is raised is not formed, so that a decrease in scratch resistance can be suppressed.
[0018]
Latent image image of fluorescent dye In the present invention, a latent image image (an image that cannot be visually recognized by visible light but can be visually recognized by irradiating special light such as ultraviolet light) is formed by the fluorescent dye. .
[0019]
The fluorescent dye that can be used in the present invention is not particularly limited. For example, known organic and inorganic fluorescent dyes can be used. Of these, organic fluorescent dyes that are colorless under normal conditions are preferred. Examples of the organic fluorescent dye include EB-501, EG-502, ER-120 manufactured by Mitsui Chemicals, Inc., EuN-0001 manufactured by Nippon Kayaku Co., Ltd., and Ubitex manufactured by Ciba Specialty Chemicals. OB, a colorless fluorescent coloring material manufactured by Sinloich Co., Ltd., various fluorescent whitening agents, etc. can be used alone or in combination of two or more.
[0020]
Examples of the image include not only an image image such as a logo mark, but also character information, and are not particularly limited.
[0021]
Dye receiving layer The dye receiving layer used in the present invention is not particularly limited as long as it is used for ordinary printed matter. Examples of materials include polyolefin resins such as polypropylene, polyvinyl chloride, vinyl chloride / vinyl acetate copolymer, halogenated polymers such as polyvinylidene chloride, vinyl polymers such as polyvinyl acetate and polyacrylic ester, polyethylene terephthalate, and poly (vinyl terephthalate). Polyester resins such as butylene terephthalate, polystyrene resins, polyamide resins, copolymer resins of olefins such as ethylene and propylene with other vinyl monomers, ionomers, cellulose resins such as cellulose diacetate, and polycarbonate. Particularly preferred are vinyl resins and polyester resins.
[0022]
Visible dye The visible dye used in the present invention (in the present specification, the "visible dye" is a dye which is compared with a fluorescent dye and means a normal dye having substantially no fluorescent effect. Is not particularly limited, and various usual dyes and dye materials used in printing can be used. The color tone is not particularly limited, but typically includes a yellow dye, a magenta dye and a cyan dye.
[0023]
Examples of such visible dyes include the following.
[0024]
Examples of the yellow sublimable dye include Foron Brilliant Yellow-S-6GL (trade name of Disperse Yellow 231 manufactured by Sando Co., Ltd.) and Macrolex Yellow 6G (trade name of Disperse Yellow 201 manufactured by Bayer Co., Ltd.).
[0025]
Examples of the magenta sublimable dye include MS-REDG (trade name of Disperse Violet 26 manufactured by Bayer AG) and the like.
[0026]
Examples of cyan sublimable dyes include Kayaset Blue 714 (trade name of Solvent Blue 63 manufactured by Nippon Kayaku Co., Ltd.), Foron Brilliant Blue SR (trade name of Disperse Blue 354 manufactured by Sando Co., Ltd.), and Waxolin AP-FW (ICI (Trade name of Solvent Blue 36, manufactured by the company).
[0027]
Examples of the black sublimable dye include a mixture of the above yellow, magenta, and cyan dyes.
[0028]
Image forming body The image forming body of the present invention is not limited as long as images and characters are formed by printing. Typically, printed paper, printed plastic cards, printed product exteriors, and the like, such as ID cards and various certificates, may be mentioned. One of the preferable aspects of the present invention is a security element which is used by being printed or pasted on an object whose copy is to be prevented.
[0029]
Further, the transfer layer of the intermediate transfer medium may be the image forming body of the present invention. In other words, after forming a visible dye by thermal diffusion transfer on the intermediate transfer medium, a dye receiving layer is provided, and then a latent image image of a fluorescent dye is formed by thermal diffusion transfer, and the latent image is re-transferred to the transfer receiving body. it can.
[0030]
Protective layer The protective layer that can be used in the present invention is not particularly limited as long as it is used for ordinary printed matter. In the present invention, if a protective layer is further formed on the latent image, even if a special confirmation method such as the use of special reflected light is used consciously, it is almost invisible under visible light, and the invisibility is higher. A latent image can be obtained.
[0031]
And a protective layer can be formed by apply | coating the coating composition containing the resin for protective layer formation to the surface of a base material by well-known coating means. The protective layer is formed to be transparent such as colorless transparent or colored transparent such that the image of the lower layer can be seen after transfer. As the protective layer forming resin, for example, polyester, polystyrene, acrylic, polyurethane, a simple substance or a mixture of resins such as acrylic urethane, a resin obtained by modifying these resins with silicone, a mixture of these modified resins, an ionizing radiation-curable resin, UV-blocking resin and the like. The thickness of the protective layer is usually formed to about 0.5 to 10 μm.
[0032]
The protective layer containing the ionizing radiation-curable resin is particularly excellent in plasticizer resistance and scratch resistance. As the ionizing radiation-curable resin, known resins can be used. For example, radically polymerizable polymers or oligomers (with a photopolymerization initiator added as necessary) are crosslinked by ionizing radiation (electron beam, ultraviolet light, etc.) And cured ones can be used.
[0033]
The ultraviolet blocking resin can be contained in the protective layer as long as it allows most of the excitation light of the fluorescent dye to pass therethrough (for example, it transmits light near 366 nm and cuts light of short wavelength). Light resistance can be imparted.
[0034]
As the ultraviolet blocking resin, for example, a resin obtained by reacting and bonding a reactive ultraviolet absorber to a thermoplastic resin or the above ionizing radiation curable resin can be used. Reactive UV absorbers include non-reactive organic UV absorbers such as salicylate, benzophenone, benzotriazole, substituted acrylonitrile, nickel-chelate, and hindered amines, and addition polymerizable double bonds (eg, Vinyl groups, acryloyl groups, methacryloyl groups, etc.), alcoholic hydroxyl groups, amino groups, carboxyl groups, epoxy groups, and reactive groups such as isocyanate groups.
[0035]
Further, a hologram pattern or the like can be formed on the protective layer. Examples of the hologram pattern include a relief pattern of a relief hologram. Further, as other patterns, an uneven pattern of a diffraction grating or the like may be used.
[0036]
Thermal diffusion transfer sheet The thermal diffusion transfer sheet of the present invention has at least a visible dye layer and a dye receiving layer on one side of a substrate sheet so that thermal dye transfer is performed in the order of a visible dye, a dye receiving layer, and a fluorescent dye. This is a heat diffusion transfer sheet in which a visible dye layer, a dye receiving layer forming layer, and a fluorescent dye layer are integrated, in which a layer forming layer and a fluorescent dye layer are provided side by side. Such a thermal diffusion transfer sheet has a portion where at least a visible dye layer is formed on a base sheet, a portion where a dye receiving layer forming layer is formed on the base sheet, and a fluorescent sheet on the base sheet. The portion where the dye layer is formed is provided in a pattern on one sheet, that is, at least the visible dye layer, the dye receiving layer forming layer, and the fluorescent dye layer are arranged face-sequentially on one base sheet. Is what it is. In such a thermal diffusion transfer sheet, first, the visible dye layer portion is heated and thermally diffusion-transferred, then the dye-receiving layer forming layer portion is heated and thermally diffusion-transferred, and the fluorescent dye layer portion is further heated and thermally diffusion-transferred. Can be used in the printing method of the present invention.
[0037]
【Example】
Example 1
A printing method in which a dye receiving layer is combined with the thermal diffusion transfer of the present invention and a printing method using a conventional thermal diffusion transfer were compared.
[0038]
As an example of the present invention, a yellow image was formed by transferring a yellow dye onto the entire surface of a white vinyl chloride card, transferring a dye-receiving layer over the entire surface, and then forming a latent image with a fluorescent dye on a fluorescent panel. On the other hand, as a conventional example, a yellow dye was transferred onto the entire surface of a white vinyl chloride card, and a latent image was formed on the white vinyl card with a fluorescent panel.
[0039]
The transfer energies of the yellow dye, dye receiving layer and fluorescent dye were all 0.18 mJ / dot.
[0040]
The yellow dye panel and the back surface were the same as those used in the usual case.
[0041]
<Dye receiving layer transfer panel>
The structure of the dye receiving layer transfer panel was composed of a heat-resistant lubricating layer / easy-adhesive PET / release layer / dye receiving layer forming layer / adhesive layer.
[0042]
Among these, the heat-resistant lubricating layer was formed by performing gravure coating on a 6 μm-thick easily-adhesive PET film using the materials shown in the following table. The film after drying was 0.5 g / m ² .
・ 3.6 parts by weight of polyvinyl butyral resin (S-REC BX-1, manufactured by Sekisui Chemical Co., Ltd.)
8.6 parts by weight of polyisocyanate (Bernock D750, manufactured by Dainippon Ink and Chemicals, Inc.)
2.8 parts by weight of phosphate ester surfactant (Plysurf A208S, manufactured by Daiichi Pharmaceutical)
・ Talc 0.7 parts by weight (Micro Ace P-3, manufactured by Nippon Talc Industry Co., Ltd.)
・ Methyl ethyl ketone 32.0 parts by weight ・ Toluene 32.0 parts by weight
The release layer was formed by gravure coating using the materials shown in the following table. The film after drying was 1.0 g / m ² .
・ 16 parts by weight of acrylic-styrene resin (Cell Top 226, manufactured by Daicel Chemical Industries)
・ 3 parts by weight of aluminum catalyst (Celltop CAT-A, manufactured by Daicel Chemical Industries)
・ Toluene 8 parts by weight ・ Methyl ethyl ketone 8 parts by weight
The dye receiving layer forming layer was formed by gravure coating using the materials shown in the following table. The film after drying was 1.5 g / m ² .
・ 100 parts by weight of vinyl chloride-vinyl acetate copolymer (# 1000AS, manufactured by Denki Kagaku Kogyo)
・ 5 parts by weight of amino-modified silicone (X-22-343, manufactured by Shin-Etsu Chemical Co., Ltd.)
・ 5 parts by weight of epoxy-modified silicone (KF-393, manufactured by Shin-Etsu Chemical Co., Ltd.)
・ Toluene 250 parts by weight ・ Methyl ethyl ketone 250 parts by weight
The adhesive layer was formed by gravure coating using the materials shown in the following table. The film after drying was 1.5 g / m ² .
・ Ethylene-vinyl acetate copolymer resin heat sealant 100 parts by weight (AD-37P295, manufactured by Toyo Morton)
・ 100 parts by weight of ion-exchanged water [0046]
<Heat diffusion transfer fluorescent panel>
The structure of the heat diffusion transferable fluorescent panel was a heat resistant slip layer / easy adhesion PET / heat diffusion transferable fluorescent coloring layer.
[0047]
Among these, the heat-resistant lubricating layer was formed by performing gravure coating on a 6 μm-thick easily-adhesive PET film using the materials shown in the following table. The film thickness after drying was 0.5 g / m ² .
・ 3.6 parts by weight of polyvinyl butyral resin (S-REC BX-1, manufactured by Sekisui Chemical Co., Ltd.)
8.6 parts by weight of polyisocyanate (Bernock D750, manufactured by Dainippon Ink and Chemicals, Inc.)
2.8 parts by weight of phosphate ester surfactant (Plysurf A208S, manufactured by Daiichi Pharmaceutical)
・ Talc 0.7 parts by weight (Micro Ace P-3, manufactured by Nippon Talc Industry Co., Ltd.)
・ Methyl ethyl ketone 32.0 parts by weight ・ Toluene 32.0 parts by weight
The thermal diffusion transferable fluorescent coloring layer was formed by gravure coating using the materials shown in the following table. The film after drying was 0.4 g / m ² .
-1.5 parts by weight of oxazole-based fluorescent dye (UVITEX OB: manufactured by Ciba Specialty Chemicals)
・ 3.5 parts by weight of polyvinyl acetoacetal resin (KS-5: manufactured by Sekisui Chemical Co., Ltd.)
-47.5 parts by weight of toluene-47.5 parts by weight of methyl ethyl ketone-0.1 part by weight of polyethylene wax
Each of an image forming body obtained by combining the thermal diffusion transfer of the present invention and the dye-receiving layer and an image forming body obtained by using the conventional thermal diffusion transfer, each having an O.D. D. Values and relative fluorescence intensities were measured. In addition, O. D. The value was measured with a Macbeth reflection densitometer RD-918 yellow filter, and the relative fluorescence intensity was measured with a spectrofluorometer FP-6600 manufactured by JASCO. The results are shown below.
[0050]
[Table 1]

As shown in this table, as compared with the case where only the yellow dye was transferred, the dye receiving layer was transferred after the transfer of the yellow dye of the present invention and then the fluorescent dye was transferred, and no decrease in the density of yellow was observed. However, when the fluorescent dye was transferred without the dye receiving layer after the transfer of the conventional yellow dye, a decrease in the yellow density was observed due to the influence of the back trap. In addition, the transfer of the dye receiving layer after the transfer of the yellow dye of the present invention, and then the transfer of the fluorescent dye, the decrease in the fluorescence intensity compared to the transfer of the fluorescent dye without the dye receiving layer after the transfer of the conventional yellow dye. Was suppressed.
[0051]
Example 2
A protective layer was further provided on the image forming body of the present invention obtained in Example 1 above.
The protective layer was formed by gravure coating using the materials shown in the following table. The film after drying was 1 g / m ² .
・ 30 parts by weight of vinyl chloride vinyl acetate copolymer resin (VY-LFX manufactured by Union Carbide Co., Ltd.)
-35 parts by weight of toluene-35 parts by weight of methyl ethyl ketone By providing the protective layer, an image forming body with higher invisibility was obtained.
[0052]
【The invention's effect】
In the present invention, after the transfer of the visible dye, by transferring the dye-receiving layer, it is possible to suppress a decrease in the density of the image due to the back trap during the transfer of the fluorescent dye, and to thermally diffuse and transfer the fluorescent dye there. By providing a latent image, it is possible to form a latent image without unevenness of the image and without quenching of fluorescence due to coexistence with a visible dye.
[Brief description of the drawings]
FIG. 1 is a diagram for explaining a conventional technique of a printing method using thermal fusion transfer.
FIG. 2 is a diagram illustrating a conventional technique of a printing method using thermal diffusion transfer.
FIG. 3 is a diagram illustrating an example of a printing method using a thermal diffusion transfer and a dye receiving layer according to the present invention.
[Explanation of symbols]
11, 21, 31 Image receiving paper 12, 22, 32 Yellow dye 13, 23, 33 Magenta dye 14, 24, 34 Cyan dye 15, 25, 35 Fluorescent dye 16 Protective layer 27 Fluorescent dye ink ribbon 28 Visible dye transfer site 39 Dye Reception layer

Claims (8)

A first step of forming an image with a visible dye by thermal diffusion transfer,
A printing method, comprising: a second step of transferring a dye-receiving layer onto the image; and a third step of forming a latent image of a fluorescent dye on the dye-receiving layer by thermal diffusion transfer. The printing method according to claim 1, wherein the visible dye is a dye selected from a yellow dye, a magenta dye, and a cyan dye. The printing method according to claim 1, further comprising a step of forming a protective layer after the third step. An image forming body comprising: a dye receiving layer provided on a visible dye image formed by thermal diffusion transfer; and a latent image of a fluorescent dye formed by thermal diffusion transfer on the dye receiving layer. The image forming body according to claim 4, wherein the visible dye is a dye selected from a yellow dye, a magenta dye, and a cyan dye. The image forming body according to claim 4, wherein a protective layer is further formed on the latent image. A security element comprising the image forming body according to claim 4. Visible dye, dye receiving layer, and fluorescent dye in order to perform thermal diffusion transfer, on one surface of the base sheet, at least a visible dye layer, a dye receiving layer forming layer and a fluorescent dye layer are arranged side by side, Dye receiving layer forming layer / fluorescent dye layer integrated type thermal diffusion transfer sheet.

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