Print manufacturing method

Abstract

To suppress output of laser and form a fine pattern in a color layer.SOLUTION: A method for manufacturing a printed matter includes the steps of: irradiating a thermal transfer sheet having a release layer containing a white pigment, a colored layer containing a black pigment and an adhesive layer in this order on a base material with laser in a first pattern, and removing the colored layer and the adhesive layer corresponding to a laser irradiation region; and heating the thermal transfer sheet after laser irradiation, and transferring the colored layer and the adhesive layer onto a transferred body. Reflectance of a laser beam in the release layer containing the white pigment is high, energy by the irradiation laser is efficiently applied to the colored layer, and the colored layer can be removed.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present disclosure relates to a method for producing a print. [Background technology]

[0002] 2. Description of the Related Art Microtext is printed to enhance security on media that require prevention of counterfeiting, such as securities including vouchers and prepaid cards, and identification cards including driver's licenses.

[0003] Conventionally, micro characters are formed by offset printing using resin relief printing or the like, so the character information cannot be changed and security is insufficient.

[0004] Cited document 1 describes a printing method in which an infrared laser is used to print and evaporate carbon ink on an ink ribbon, forming arbitrary micro-characters in the carbon ink, and then transferring the carbon ink with the micro-characters formed onto a receiving medium.

[0005] However, the printing method described in Patent Document 1 required high output power of the infrared laser to print and evaporate the carbon ink. Also, the printing method described in Patent Document 1 could form micro-characters on carbon ink (black ink) that has a high light absorption rate in the infrared region, but could not form micro-characters on inks of other colors, such as yellow, that have a low light absorption rate in the infrared region. [Prior art documents] [Patent documents]

[0006] [Patent Document 1] Japanese Patent Application Laid-Open No. 2011-152652 Summary of the Invention [Problem to be solved by the invention]

[0007] An object of the present disclosure is to provide a method for manufacturing a printed matter that can form a fine pattern in a colored layer while suppressing laser output. Another object of the present disclosure is to provide a method for manufacturing a printed matter that can form a fine pattern in a colored layer of any color. [Means for solving the problem]

[0008] The method for manufacturing a printed matter disclosed herein comprises the steps of irradiating a thermal transfer sheet having a release layer containing a white pigment, a colored layer containing a black pigment, and an adhesive layer provided in that order on a substrate with a laser in a first pattern to remove the colored layer and the adhesive layer corresponding to the laser irradiated area, and heating the thermal transfer sheet after laser irradiation to transfer the colored layer and the adhesive layer to a transfer target.

[0009] The method for manufacturing a printed matter disclosed herein comprises the steps of irradiating a thermal transfer sheet having a release layer containing a black pigment, a colored layer containing a pigment of a color other than black, and an adhesive layer, in that order, on a substrate with a laser in a first pattern to remove the release layer, the colored layer, and the adhesive layer corresponding to the laser irradiated area, and heating the thermal transfer sheet after laser irradiation to transfer the colored layer and the adhesive layer to a transfer target. [Effects of the Invention]

[0010] According to the present disclosure, a fine pattern can be formed in a colored layer while suppressing laser output. Also, according to the present disclosure, a fine pattern can be formed in a colored layer of any color. [Brief explanation of the drawings]

[0011] [Figure 1] FIG. 1 is a cross-sectional view of a thermal transfer sheet according to an embodiment of the present disclosure. [Figure 2] FIG. 10 is a cross-sectional view illustrating a first pattern forming process by laser irradiation. [Figure 3] FIG. 10 is a plan view illustrating a first pattern forming process by laser irradiation. [Figure 4] 10A to 10C are cross-sectional views illustrating a second pattern forming process by transferring a colored layer. [Figure 5] FIG. [Figure 6] FIG. 10 is a cross-sectional view of a thermal transfer sheet according to another embodiment. [Figure 7] FIG. 10 is a cross-sectional view illustrating a first pattern forming process by laser irradiation. DETAILED DESCRIPTION OF THE INVENTION

[0012] Hereinafter, embodiments of the present disclosure will be described with reference to the drawings. To clarify the description, the drawings may show the width, thickness, etc. of each part more schematically than in the actual embodiment. However, these are merely examples and are not intended to limit the interpretation of the present disclosure. In the present specification and drawings, elements similar to those previously described with reference to the preceding drawings are designated by the same reference numerals, and detailed descriptions may be omitted as appropriate.

[0013] 1 is a cross-sectional view of a thermal transfer sheet S used in the method for producing a print according to this embodiment. The thermal transfer sheet S has a release layer 2, a colored layer 3, and an adhesive layer 4 laminated in this order on one surface of a substrate 1. A heat-resistant layer 5 is provided on the other surface of the substrate 1.

[0014] The colored layer 3 and adhesive layer 4 are layers that are transferred to the transfer-receiving body 7 in a thermal transfer process described later. The release layer 2 is not transferred to the transfer-receiving body 7 and remains on the substrate 1.

[0015] <Base material> The substrate 1 can be appropriately selected from those conventionally known in the field of thermal transfer sheets. Examples include stretched or unstretched plastic films such as highly heat-resistant polyesters such as polyethylene terephthalate, polyethylene naphthalate, polybutylene terephthalate, polyphenylene sulfide, polyether ketone, and polyether sulfone, polypropylene, polycarbonate, cellulose acetate, polyethylene derivatives, polyvinyl chloride, polyvinylidene chloride, polystyrene, polyamide, polyimide, polymethylpentene, and ionomers. Composite films made by laminating two or more of these materials can also be used.

[0016] <Release layer> The release layer 2 is provided to adjust the adhesion between the substrate 1 and the colored layer 3 and to facilitate the peeling of the colored layer 3. The release layer 2 according to this embodiment contains a component having releasability and a white pigment.

[0017] Examples of components having releasability include waxes, silicone waxes, silicone resins, various silicone-modified resins such as silicone-modified acrylic resins, fluororesins, fluororesin-modified resins, polyvinyl alcohol, acrylic resins, thermosetting epoxy-amino copolymers, and thermosetting alkyd-amino copolymers (thermosetting aminoalkyd resins), melamine resins, cellulose resins, urea resins, polyolefins, and acrylic resins.

[0018] Examples of white pigments include titanium oxide, zinc oxide, aluminum hydroxide, magnesium carbonate, calcium carbonate, silica, and talc.

[0019] The content of the white pigment in the release layer 2 is preferably 50% by mass or more and 90% by mass or less.

[0020] The release layer 2 can be formed by applying a coating liquid containing at least one selected from the group consisting of the above waxes and the above resins and a white pigment onto the substrate 1 according to a conventionally known coating method, and then drying the liquid. The thickness of the release layer 2 after drying is approximately 0.1 μm or more and 20 μm or less.

[0021] <Colored layer> The colored layer 3 is a melt-transfer type colored layer in which the colored layer itself is transferred. The colored layer 3 contains a black pigment such as carbon black or magnetite triiron tetroxide as a coloring material. The colored layer also contains a resin material. Examples of the resin material include polyester, polyamide, polyolefin, vinyl resin, (meth)acrylic resin, cellulose resin, styrene resin, polycarbonate, and ionomer resin.

[0022] The colored layer 3 can be formed by dispersing or dissolving the above-mentioned material in water or a suitable solvent, applying it to the release layer 2 by known means such as roll coating, reverse roll coating, gravure coating, reverse gravure coating, bar coating, and rod coating to form a coating film, and then drying it.

[0023] The thickness of the colored layer 3 is preferably 0.1 μm or more and 20 μm or less, and more preferably 0.4 μm or more and 0.8 μm or less. By setting the thickness of the colored layer to 0.8 μm or less, high ink removability is achieved, and the colored layer can be removed with low laser energy when evaporating and removing the colored layer by laser irradiation, as described below. If the thickness of the colored layer exceeds 0.8 μm, it is preferable to set the laser energy to 5.0 mJ / pulse or more.

[0024] <Adhesive layer> The adhesive layer 4 is the layer located on the outermost surface of the thermal transfer sheet S and improves adhesion to the transfer-receiving body. The adhesive layer 4 contains at least one thermoplastic resin that softens when heated and exhibits adhesion. Examples of thermoplastic resins include polyester, vinyl resin, (meth)acrylic resin, polyurethane, cellulose resin, polyamide, polyolefin, polystyrene, and chlorinated resins thereof.

[0025] The adhesive layer 4 can be formed by dispersing or dissolving the above-mentioned material in water or a suitable solvent, applying it onto the colored layer 3 by known means such as roll coating, reverse roll coating, gravure coating, reverse gravure coating, bar coating, or rod coating to form a coating film, and then drying it.

[0026] The thickness of the adhesive layer 4 is not particularly limited, but can be set to 0.1 μm or more and 1.0 μm or less.

[0027] <Heat-resistant layer> The heat-resistant layer 5 is a layer provided to prevent adverse effects such as sticking and wrinkling caused by heat from the back side of the substrate 1 (the side of the substrate 1 on which the colored layer 3, etc., is not provided) during thermal transfer. By providing a heat-resistant layer, thermal printing is possible without sticking even on thermal transfer sheets whose substrate is a plastic film with poor heat resistance, and the advantages of plastic film, such as its resistance to tearing and ease of processing, can be utilized.

[0028] The heat-resistant layer preferably contains a binder resin and additives such as a slipping agent. Examples of binder resins used in the heat-resistant layer include acrylic resins such as poly(meth)acrylate and poly(meth)acrylamide, vinyl resins such as polyvinyl alcohol resin, polyvinyl acetate resin, vinyl chloride-vinyl acetate resin, polyvinyl butyral resin, polyvinyl acetal resin, and polyvinyl pyrrolidone, polyester resins such as polyethylene terephthalate resin and polyethylene naphthalate resin, urethane resins such as polyurethane acrylate, cellulose resins such as ethyl cellulose resin, hydroxyethyl cellulose resin, ethylhydroxycellulose resin, methyl cellulose resin, and cellulose acetate resin, polyamide resins such as polyamide resin, aromatic polyamide resin, and polyamideimide resin, acetal resins, and polycarbonate resins. Examples of slipping agents include metal soap, wax, silicone oil, fatty acid ester, filler, and talc.

[0029] The method for forming the heat-resistant layer is not particularly limited, but can be formed by a conventionally known coating method. For example, the above-mentioned binder resin and, if necessary, additives such as a slipping agent are added to an appropriate solvent, and each component is dissolved or dispersed to prepare a coating solution. This coating solution is then applied to a substrate using a known method such as gravure coating, roll coating, comma coating, gravure printing, screen printing, or gravure reverse roll coating, and then dried to form the heat-resistant layer. The thickness of the heat-resistant layer is not particularly limited, but can be, for example, 0.05 μm or more and 5.0 μm or less.

[0030] Next, a method for producing a print using such a thermal transfer sheet S will be described.

[0031] As shown in Figure 2, an infrared laser L is irradiated onto the thermal transfer sheet S using a laser irradiation device (not shown). The infrared laser L is irradiated from the side of the thermal transfer sheet S where the adhesive layer 4 is provided. By irradiating the infrared laser L, the black colored layer 3 in the laser irradiated area is evaporated and removed. At this time, the adhesive layer 4 on the colored layer 3 is also removed together with the colored layer 3.

[0032] In this embodiment, the release layer 2 located below the colored layer 3 contains a white pigment, so that the reflectivity of the laser light in the release layer 2 is high, and the energy from the irradiated laser can be efficiently applied to the colored layer 3, thereby removing the colored layer 3.

[0033] As a result, as shown in Fig. 3, a first pattern P1 corresponding to the irradiation pattern of the infrared laser L can be formed on the colored layer 3. The irradiation pattern may be characters, figures, or symbols. The first pattern P1 is a fine pattern corresponding to the beam diameter of the infrared laser L. Fig. 3 shows an example in which micro characters are formed as the first pattern P1.

[0034] The infrared laser L can be a gas laser, semiconductor laser, YAG laser, YVO4 laser, or the like. For example, a semiconductor laser can have a central wavelength of 820 nm and a beam diameter of 200 μm or less. A YAG laser or YVO4 laser can have a central wavelength of 1064 nm and a beam diameter of 10 μm or less. This makes it possible to form micro-characters with a line width of 10 μm on the colored layer 3.

[0035] Next, the thermal transfer sheet S is heated from the heat-resistant layer 5 side by a thermal head (not shown), and the colored layer 3 and adhesive layer 4 are transferred onto the transfer-receiving body 7 as shown in FIG.

[0036] Heating by the thermal head may be a solid pattern or a pattern of letters, symbols, etc. Figure 5 shows an example in which the thermal transfer sheet S is heated by the thermal head in a letter pattern, and the colored layer 3 and adhesive layer 4 are transferred onto the transfer recipient 7 in a second pattern P2 corresponding to the heating pattern.

[0037] In this example, the character size of the second pattern P2 is larger than the character size of the first pattern P1. More specifically, the line width of the characters in the second pattern P2 is larger than the character size of the first pattern P1, and multiple first patterns P1 are included on the line of the second pattern P2. As a result, the micro character "D" can be formed like a hollow character on the line of the characters "ABC."

[0038] The transfer object 7 is not particularly limited, and may be, for example, a card substrate, an intermediate transfer medium, an image receiving sheet having a receiving layer provided on one surface of a substrate, or the like.

[0039] The card substrate is made of a synthetic resin such as polyvinyl chloride, polyester, polycarbonate, polyamide, polyimide, cellulose diacetate, cellulose triacetate, polystyrene resin, acrylic resin, polypropylene, or polyethylene.

[0040] The colored layer 3 and adhesive layer 4 may be transferred onto the transfer layer of the intermediate transfer medium, and then the transfer layer, adhesive layer 4 and colored layer 3 may be transferred from the intermediate transfer medium onto the card substrate.

[0041] As described above, according to this embodiment, the release layer 2 contains a white pigment to increase the reflectivity of the laser light, and energy is applied to the colored layer 3 efficiently, so that a fine pattern can be formed in the colored layer 3 while suppressing the laser output.

[0042] The substrate 1 may contain a white pigment instead of the release layer 2. That is, the substrate 1 may be a white substrate. By using a white substrate for the substrate 1, the reflectance of the laser light from the white substrate is improved, and the reflected laser light reaches the colored layer 3, allowing energy to be applied to the colored layer 3 efficiently.

[0043] In the above embodiment, an example has been described in which the colored layer 3 contains a black pigment so as to increase the light absorptance in the wavelength region of the infrared laser, but the colored layer may contain a pigment of a color other than black, such as yellow, magenta, cyan, etc. In this case, as shown in Fig. 6, a release layer 2A containing a black pigment is formed on the substrate 1, and a colored layer 3A containing a pigment of a color other than black is formed on the release layer 2A.

[0044] Examples of pigments other than black contained in the colored layer 3 include azo pigments, azo lake pigments, phthalocyanine pigments, anthraquinone pigments, indigo / thioindigo pigments, perylene / perinone pigments, isoindolinone pigments, quinacridone pigments, and indanthrene pigments.

[0045] 7, the black release layer 2A in the laser irradiated portion is evaporated and removed by irradiation with the infrared laser L. At this time, the colored layer 3A and adhesive layer 4 on the release layer 2A are also removed together with the release layer 2A.

[0046] In this way, by including a black pigment in the release layer 2A, a fine pattern can be formed in the colored layer 3A of a color other than black by laser irradiation.

[0047] Although the present disclosure has been described in detail with reference to specific embodiments, it will be apparent to those skilled in the art that various modifications can be made without departing from the spirit and scope of the present disclosure. [Explanation of symbols]

[0048] 1 Base material 2 Release layer 3 Colored layer 4 Adhesive layer 5 Heat-resistant layer 7 Transferred object

Claims

1. a step of irradiating a thermal transfer sheet having a release layer containing a white pigment, a colored layer containing a black pigment, and an adhesive layer provided in this order on a substrate with a laser in a first pattern, and removing the colored layer and the adhesive layer corresponding to the laser irradiated area; a step of heating the thermal transfer sheet after the laser irradiation and transferring the colored layer and the adhesive layer to a transfer receiving body; A method for manufacturing a printed matter comprising the steps of:

2. a step of irradiating a thermal transfer sheet having a release layer, a colored layer containing a black pigment, and an adhesive layer provided in this order on a white substrate with a laser in a first pattern, and removing the colored layer and the adhesive layer corresponding to the laser irradiated areas; a step of heating the thermal transfer sheet after the laser irradiation and transferring the colored layer and the adhesive layer to a transfer receiving body; A method for manufacturing a printed matter comprising the steps of:

3. a step of irradiating a thermal transfer sheet having a release layer containing a black pigment, a colored layer containing a pigment of a color other than black, and an adhesive layer provided in this order on a substrate with a laser in a first pattern, and removing the release layer, the colored layer, and the adhesive layer corresponding to the laser irradiated area; a step of heating the thermal transfer sheet after the laser irradiation and transferring the colored layer and the adhesive layer to a transfer receiving body; A method for manufacturing a printed matter comprising the steps of:

4. The method for producing a print according to claim 1 , wherein the thermal transfer sheet is heated with a second pattern larger in size than the first pattern, and the colored layer and the adhesive layer are transferred to the transfer-receiving body.

5. The method for producing a print according to claim 4 , wherein the line width of the second pattern is larger than the size of the first pattern.

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