Thermal transfer sheet, method for manufacturing printed matter, authenticity determination method, and authenticity determination system

Abstract

The present disclosure enables authenticity determination of a product by being used for printing on the product. A thermal transfer sheet according to the present disclosure comprises: a substrate; and a transfer layer that is provided on one surface of the substrate and is transferred to a transfer target. The transfer layer includes an identification tag having a spectral profile that is identifiable in association with predetermined information. The transfer layer may contain at least one of a coloring material and an invisible light absorbing material. Alternatively, the transfer layer may have a first transfer layer and a second transfer layer provided in surface sequence, the first transfer layer may contain the identification tag, and the second transfer layer may contain at least one of a coloring material and an invisible light absorbing material.

Description

Thermal transfer sheet, method for producing printed matter, authenticity determination method and authenticity determination system

[0001] The present disclosure relates to a thermal transfer sheet, a method for producing printed matter, an authenticity determination method, and an authenticity determination system.

[0002] Conventionally, various thermal transfer recording methods are known. For example, there is known a hot-melt transfer method in which a thermal transfer sheet including a hot-melt ink layer containing hot-melt ink is overlapped with an image receiving sheet, the thermal transfer sheet is heated by a thermal head provided in a thermal transfer printer, and the hot-melt ink layer is transferred onto the image receiving sheet to form an image. Images formed by the hot-melt transfer method have high density and excellent sharpness, and thus are used for printing product packages, printing barcodes, and the like.

[0003] With the recent spread of e-commerce sites, counterfeit products are increasing year by year, and product producers are plagued by the counterfeit product problem. In the distribution process from producers to consumers, there is a demand for a technology that can easily determine the authenticity of products. In particular, there is a demand for a technology for adding elements for authenticity determination in the printing / printing process during product manufacturing.

[0004] Japanese Patent No. 5855646, International Publication No. WO 2023 / 038138

[0005] An object of the present disclosure is to provide a thermal transfer sheet that enables authenticity determination of a product when used for printing on the product. Another object of the present disclosure is to provide a method for producing printed matter using the thermal transfer sheet, and an authenticity determination method and an authenticity determination system for the printed matter.

[0006] [1] A thermal transfer sheet comprising: a base material; and a transfer layer provided on one surface of the base material and transferred to a transfer-receiving object, wherein the transfer layer includes an identification tag having a spectral profile that can be identified in association with predetermined information.

[0007] [2] The thermal transfer sheet according to [1], wherein the spectral profile has a specific reflection pattern or a fluorescent X-ray spectrum.

[0008] [3] The thermal transfer sheet according to [2], wherein the reflection pattern has a specific reflection spectrum, reflection peak, or reflection amplitude.

[0009] [4] The thermal transfer sheet according to [3], wherein the identification tag comprises porous particles having pores with a diameter in the nanometer range or an optical effect pigment.

[0010] [5] The thermal transfer sheet according to [4] wherein the porous particles have at least one type of pore selected from the group consisting of (a1) to (a3): (a1) micropores with a diameter of 0.001 nm or more and less than 2 nm, (a2) mesopores with a diameter of 2 nm or more and 50 nm or less, and (a3) ​​macropores with a diameter greater than 50 nm and 1000 nm or less.

[0011] [6] The thermal transfer sheet according to [4] or [5], wherein the average particle size of the porous particles is 10 μm or more and 150 μm or less.

[0012] [7] The thermal transfer sheet according to any one of [4] to [6], wherein the porous particles are plate-shaped or flake-shaped.

[0013] [8] The thermal transfer sheet according to [7], wherein the thickness of the porous particles is 0.1 μm or more and 10 μm or less.

[0014] [9] The thermal transfer sheet according to any one of [4] to [8], wherein the porous particles are porous silica particles.

[0015]

[10] The heat transfer sheet according to any one of [1] to [9], wherein the ratio A / B of the thickness A of the transfer layer to the thickness B of the identification tag is 0.09 or more and 2.33 or less.

[0016]

[11] The amount of the identification tag added to the transfer layer is 0.05% by mass or more and 30% by mass or less, according to any one of [1] to

[10] .

[0017]

[12] The heat transfer sheet according to any one of [1] to

[11] , wherein the transfer layer contains at least one of a coloring agent and an invisible light absorbing material.

[0018]

[13] The heat transfer sheet according to any one of [1] to

[12] , wherein the transfer layer comprises a first transfer layer and a second transfer layer, the first transfer layer and the second transfer layer are provided in sequence repeatedly along the longitudinal direction of the heat transfer sheet, the first transfer layer contains the identification tag, and the second transfer layer contains at least one of a coloring agent and an invisible light absorbing material.

[0019]

[14] A method for manufacturing a printed object, comprising heating a heat transfer sheet according to any one of [1] to

[13] and transferring the transfer layer onto a transfer object to produce a printed object.

[0020]

[15] The method for manufacturing a printed object according to

[14] , wherein the object to be transferred is a label.

[0021]

[16] A method for manufacturing a printed object, comprising heating the heat transfer sheet described in

[12] and transferring the transfer layer onto a transfer object in a predetermined code pattern.

[0022]

[17] A method for manufacturing a printed object, comprising heating the heat transfer sheet described in

[13] , transferring the first transfer layer onto a transfer object, and transferring the second transfer layer onto the transfer object in a predetermined code pattern.

[0023]

[18] A method for determining authenticity of a printed object, comprising: using a code reader to read code information from the code pattern formed on a printed object manufactured by the method for manufacturing a printed object described in

[16] ; using an optical spectrometer to read a reflection pattern from the code pattern on the printed object; comparing the code information and the reflection pattern with predetermined information; and determining the authenticity of the printed object.

[0024]

[19] A method for determining authenticity of a printed object, comprising: using a code reader to read code information from the code pattern of the second transfer layer formed on a printed object manufactured by the method for manufacturing a printed object described in

[17] ; using an optical spectrometer to read a reflection pattern from the area on which the first transfer layer has been transferred; comparing the code information and the reflection pattern with predetermined information; and determining the authenticity of the printed object.

[0025] A genuineness determination system comprising: a code reader for reading code information from a code pattern formed on a printed object manufactured by the method for manufacturing a printed object described in

[16] ; an optical spectrometer for reading a reflection pattern from the code pattern on the printed object; and a determination device for determining the authenticity of the printed object by comparing the code information and the reflection pattern with predetermined information.

[0026] A genuineness determination system comprising: a code reader for reading code information from the code pattern of the second transfer layer formed on a printed object manufactured by the method for manufacturing a printed object described in

[21]

[17] ; an optical spectrometer for reading a reflection pattern from the region on which the first transfer layer has been transferred; and a determination device for determining the authenticity of the printed object by comparing the code information and the reflection pattern with predetermined information.

[0027] According to this disclosure, using this technology to print expiration dates, barcodes, etc., on products will enable the determination of product authenticity and serve as a countermeasure against counterfeit goods.

[0028] This is a cross-sectional view of a thermal transfer sheet according to an embodiment of the present disclosure. This is a cross-sectional view of the transfer layer transferred to a transfer object. This is a cross-sectional view of a thermal transfer sheet according to another embodiment. This is a plan view of a thermal transfer sheet according to another embodiment. This is a plan view of a thermal transfer sheet according to another embodiment. This is a plan view of a thermal transfer sheet according to another embodiment. This is a schematic configuration diagram of a counterfeit detection system according to an embodiment of the present disclosure. This is a flowchart illustrating a counterfeit detection method according to an embodiment of the present disclosure.

[0029] The embodiments of this disclosure will be described below with reference to the drawings and other illustrations. It should be noted that this disclosure can be implemented in many different ways, and should not be interpreted as being limited to the embodiments described below. Furthermore, in order to clarify the explanation, the drawings may schematically represent the width, thickness, etc., of each part compared to the actual embodiments; however, these are merely examples and should not limit the interpretation of this disclosure.

[0030] Figure 1 is a cross-sectional view of a thermal transfer sheet S1 according to an embodiment of the present disclosure. As shown in Figure 1, the thermal transfer sheet S1 includes a base material 10, a transfer layer T1 provided on one side of the base material 10, and a back layer 14 provided on the other side of the base material 10.

[0031] The transfer layer T1 has a release layer 11, a coloring layer 12, and an adhesive layer 13 that are laminated in order from the substrate 10 side. An identification tag, described later, exists in any of the layers or multiple layers that make up the transfer layer. It is preferable that the identification tag is located in a part of the transfer layer close to the surface after transfer. The location of the identification tag close to the surface improves the accuracy of reading the identification tag.

[0032] The transfer layer T1, which includes a release layer 11, a coloring layer 12, and an adhesive layer 13, is a layer that is transferred to the transfer target 20 by a thermal transfer process, as shown in Figure 2. For example, a thermal transfer sheet S and the transfer target 20 can be sandwiched between the thermal head and platen roller of a known thermal transfer printer, and the thermal transfer sheet S can be heated from the back layer 14 side by the thermal head to transfer the transfer layer T1 to the transfer target 20 in a predetermined pattern. The transfer target 20 (printed object) to which the transfer layer T1 has been transferred can be used, for example, in product packaging.

[0033] The object to be transferred 20 may be a label (adhesive sheet). The label onto which the transfer layer T1 has been transferred can be attached to product packaging or the item itself for use.

[0034] As shown in Figure 3, the colored layer 12 may be omitted, and the heat transfer sheet S2 may have a transfer layer T2 consisting of a release layer 11 and an adhesive layer 13. In this case, the adhesive layer 13 may be colorless or may be a layer containing a coloring agent. Even in this case, the identification tag exists across any layer or multiple layers constituting the transfer layer. It is preferable that the identification tag is located in a part of the transfer layer close to the surface after transfer. The accuracy of reading the identification tag is improved when it is located in a part close to the surface.

[0035] <Identification Tag> The identification tag contained in the release layer 11 or the colored layer 12 has a spectral profile that can be identified by linking it with predetermined information. The predetermined information is, for example, manufacturer information or product information, enabling authentication, identification, and tracking of the product having the transfer body 20 onto which the transfer layers T1 and T2 have been transferred.

[0036] The identification tag is not particularly limited as long as it has a spectral profile that can be identified by linking it with predetermined information. For example, silica particles described in Japanese Patent Publication No. 2013-531849 can be used, and XRF-identifiable markers described in Japanese Patent Publication No. 2019-529676 can also be used by linking a specific spectral profile using the XRF-identifiable marker with predetermined information in advance. Optical effect pigments can also be used. Among these, it is preferable that the identification tag includes porous particles such as porous silica particles having pores with a diameter in the nanometer range.

[0037] Porous silica particles include silica particles having a nanoporous structure, in which countless pores with a diameter in the nanometer range, preferably micropores, mesopores, or macropores, are formed on the surface of high-purity silica particles.

[0038] Using an optical spectrometer, it is possible to read reflection patterns in the spectral profile that differ in at least one of the peak position, waveform shape, and amplitude, depending on structural parameters of porous particles such as pore size, pore distribution, particle size, and thickness. Such specific reflection patterns based on the structural parameters of porous particles can be used as spectral (optical) labels.

[0039] Specifically, when an optical spectroscopic reader such as a hyperspectral camera manufactured by TrueTag Inc. is used, a specific reflection pattern (reflection spectrum, reflection peak, reflection amplitude, etc.) based on the shape of the pores (fine pores) of the porous particles can be obtained and read. That is, the porous particles can be read using an optical spectroscopic reader. Note that the optical spectroscopic reader may be configured such that software or an application is installed on a smartphone, a tablet terminal, or the like to enable reading using the same.

[0040] As used herein, the "reflection pattern" refers to a characteristic pattern obtained by analysis of a spectral profile including at least any one of the above reflection spectrum, reflection peak, and reflection amplitude. A spectral profile including a reflection spectrum, a reflection peak, and a reflection amplitude is obtained by spectroscopically analyzing reflected light of light applied to an identification tag with an optical spectroscopic reader.

[0041] The identification tag is not limited to porous silica particles, and particles or microstructures having an identifiable spectral profile based on light reflection characteristics can be used.

[0042] For example, the XRF-identifiable marker described above has a fluorescent X-ray spectrum. In XRF, the emission of characteristic "secondary" (or fluorescent) X-rays from a material excited by primary X-rays or gamma radiation is detected. The term fluorescence refers to the absorption of radiation of a specific energy, resulting in re-emission of radiation of a different energy (typically lower energy). The XRF phenomenon is based on the fact that when a material is exposed to short-wavelength X-rays or gamma rays, electrons are emitted from atoms in inner orbitals, whereby electrons in higher orbitals "fall" to lower / inner orbitals, and in this process, emit a photon having an energy equal to the energy difference between the two relevant orbitals.

[0043] Optical effect pigments usable as identification tags have a structure including a base material (core) made of a metal material, glass material, inorganic material or organic material, and a coating layer formed on the surface of the base material. As the base material (core), metals such as aluminum, glass, silica, mica, oxides, resin particles and the like can be used. As the coating layer, an inorganic material, an organic material, or a composite material of these can be used.

[0044] Examples of such optical effect pigments include pearl pigments, holographic pigments, metallic pigments, flat interference pigments, glitter pigments, opal pigments, etc., but the pigments are not limited to these names and classifications, and broadly include pigments that exhibit similar optical effects.

[0045] Examples of the material of the above porous particles include silica, silicon oxide films, silicon nitride films, polysilicon, tungsten, titanium, gallium arsenide, indium tin oxide, aluminum, and copper. From the viewpoint of heat resistance, silica, silicon oxide films, silicon nitride films, polysilicon, tungsten, titanium, gallium arsenide, and indium tin oxide are preferable, and silica is more preferable.

[0046] Authentication and identification of an article can be performed by irradiating light onto the article having a transferred body 20 to which transfer layers T1 and T2 including an identification tag have been transferred, and detecting a specific reflection pattern. Since this reflection pattern varies depending on the structure (shape) of nanometer-scale pores, by associating the reflection pattern with manufacturer information, article information and the like in advance, it can be applied to authentication and identification of various products.

[0047] The pores of the porous particles preferably have a diameter of 0.001 nm (10 －１２ m) or more and 100 nm (10 －７ m) or less, more preferably a diameter of 0.001 nm (10 －１２ m) or more and 10 nm (10 －８ m) or less, and most preferably a diameter of 0.001 nm (10 －１２ m) or more and 1 nm (10 －９ m) or less.

[0048] The porous particles include at least one selected from the group consisting of (a1) to (a3) ​​below: (a1) Porous particles having micropores with a pore diameter of 0.001 nm or more and less than 2 nm; (a2) Porous particles having mesopores with a pore diameter of 2 nm or more and 50 nm; (a3) ​​Porous particles having macropores with a pore diameter greater than 50 nm and 1000 nm or less.

[0049] The average particle size of the porous particles is preferably 10 μm to 150 μm, more preferably 10 μm to 100 μm, even more preferably 10 μm to 50 μm, and most preferably 10 μm to 35 μm. If the average particle size is 10 μm or more, the performance is fully realized, such as obtaining a specific reflection pattern. If the average particle size is 150 μm or less, the dispersibility of the silica particles is sufficient.

[0050] The average particle size of porous particles can be determined by measuring the diameters of 10 or more particles using a scanning electron microscope (SEM) (SU1510) manufactured by Hitachi High-Technologies, and then calculating the average value. In the case of non-spherical particles, the average of the longest and shortest diameters can be used as the diameter of each particle. If particles are present on the outermost surface of the transfer layer, the average particle size can be measured from the transfer layer surface image using SEM. To extract individual particles, the transfer layer can be dissolved in a solvent to extract the particles, which can then be dried, and the average particle size can be measured using SEM. Unless otherwise specified, the average particle size of porous particles in this specification refers to the value measured by this method.

[0051] The shape of the porous particles is not particularly limited, but examples include plate-like and scale-like shapes. The thickness of porous particles of this shape is preferably 0.1 μm to 10 μm, more preferably 0.5 μm to 5.0 μm. If the thickness is 0.1 μm or more, the performance is fully realized, such as obtaining a specific reflection pattern. If the thickness is 10 μm or less, it becomes easier to retain the identification tag in the transfer layer, and the loss of the identification tag can be suppressed.

[0052] The thickness of porous particles can be determined by measuring the thickness (maximum length in the short-side direction) of five or more particles using a Keyence VHX-6000 microscope and taking the average value. Unless otherwise specified, the average particle size of porous particles in this specification refers to the value measured by this method.

[0053] When measuring the thickness of porous particles, individual particles can be examined. To examine particles contained in a transfer layer, the transfer layer can be dissolved in a solvent to extract the particles, which can then be dried and their thickness measured using a scanning electron microscope (SEM).

[0054] <Substrate> The material constituting the substrate 10 of the thermal transfer sheet S can be used without particular limitations, as long as it has heat resistance that can withstand the heat of the thermal head and mechanical strength and solvent resistance that can support the transfer layer T1. Examples include polyethylene terephthalate (PET), polybutylene terephthalate, polyethylene naphthalate, cellophane, etc.

[0055] The thickness of the base material 10 is not particularly limited, but is preferably 0.5 μm or more and 50 μm or less. If the thickness of the base material 10 is 0.5 μm or more and 50 μm or less, both thermal energy transfer properties and mechanical strength can be satisfied.

[0056] <Release Layer> The release layer 11 is a layer provided on the substrate 10, which peels off from the substrate 10, is transferred, and after the transfer, is located on the outermost surface of the transfer layers T1 and T2.

[0057] The release layer 11 may contain thermoplastic resins such as poly(meth)acrylamide, polymethyl(meth)acrylate, polyethyl(meth)acrylate, and other (meth)acrylic resins; vinyl resins such as polyvinyl acetate and vinyl chloride-vinyl acetate copolymers; thermosetting resins such as unsaturated polyester, polyester, polyurethane, and cellulose resin; and ultraviolet absorbing resins.

[0058] The release layer 11 preferably contains various release agents to improve transferability, i.e., releaseability from the substrate 10. Examples of release agents include waxes, silicone waxes, phosphate esters, silicone resins, silicone-modified resins, fluororesins, fluoro-modified resins, polyvinyl alcohol, acrylic resins, thermocrosslinkable epoxy-amino resins, and thermocrosslinkable alkyd-amino resins.

[0059] The following is an example of a method for forming the release layer 11. First, a thermoplastic resin and / or thermosetting resin, and optionally added ultraviolet absorbers and various additives, are dissolved or dispersed in a suitable organic solvent or water to prepare a coating solution (solvent or dispersion) for the release layer. If an identification tag is to be included in the release layer 11, the identification tag is added to the coating solution for the release layer. Next, the coating solution for the release layer can be applied to one side of the substrate 10 by a known coating method and dried to form the release layer. The thickness of the release layer 11 is preferably 0.1 μm or more and 5.0 μm or less, and more preferably 0.2 μm or more and 2.0 μm or less. This makes it possible to improve the transferability and the resolution of the image formed on the transfer target.

[0060] The thickness of each layer in the coating (release layer, coloring layer, adhesive layer, and backing layer) can be measured using the resin embedding method. Specifically, a cut thermal transfer sheet (test specimen) is embedded in epoxy resin, and then a cross-section is formed in the thickness direction of the specimen by the ultrathin sectioning method (cutting with a microtome and diamond cutter). This cross-section is then subjected to ion sputtering (Hitachi High-Technologies Corporation, E-1045, target: Pt, current: 15 mA, 10 seconds), and a cross-sectional image of the specimen is obtained using a scanning electron microscope (Hitachi High-Technologies Corporation, A-4800 TYPE I, acceleration voltage: 3.0 kV, emission current: 10 μA, working distance: 8 mm, detector: Mix), and the thickness is measured from this image.

[0061] <Colored Layer> The colored layer 12 is a melt-transfer type colored layer that is transferred by the colored layer itself. The colored layer 12 contains black pigments such as carbon black and magnetite-type triiron tetroxide as coloring agents. The colored layer also contains a resin material. Examples of resin materials include polyester, polyamide, polyolefin, vinyl resin, (meth)acrylic resin, cellulose resin, styrene resin, polycarbonate, and ionomer resin.

[0062] The above materials are dispersed or dissolved in water or a suitable solvent to prepare a coating solution for the colored layer. If an identification tag is to be included in the colored layer 12, the identification tag is added to the coating solution for the colored layer. The coating solution for the colored layer can be applied to the release layer 11 by a known coating method and dried to form the colored layer 12.

[0063] The thickness of the colored layer 12 is preferably 0.1 μm or more and 10 μm or less, and more preferably 0.3 μm or more and 5.0 μm or less. By setting the thickness of the colored layer to 0.1 μm or more, the image density formed on the transfer target can be set to a certain level or higher, improving visibility. By setting the thickness of the colored layer to 10 μm or less, an image can be formed on the transfer target with high reproducibility of fine lines.

[0064] <Adhesive Layer> The adhesive layer 13 is located on the outermost surface of the heat transfer sheet S and improves adhesion to the object to be transferred. There are no particular limitations on the material used to form the adhesive layer 13, and conventionally known materials can be appropriately selected and used. For example, the adhesive layer 13 may include ultraviolet absorber copolymers, acrylic resins, vinyl resins, epoxy resins, polyesters, polycarbonates, butyral resins, polyamides, etc., as binder resins.

[0065] As a method for forming the adhesive layer 13, a coating solution for the adhesive layer is prepared by dispersing or dissolving the binder resin exemplified above and, if necessary, an ultraviolet absorber, antioxidant, fluorescent whitening agent, inorganic or organic filler component, surfactant, mold release agent, etc., in a suitable solvent. This solution is then applied and dried using methods such as gravure coating or gravure reverse coating so that it becomes the outermost layer of the thermal transfer sheet, i.e., the outermost layer of the transfer layer (for example, on the colored layer 12). There are no particular limitations on the thickness of the adhesive layer 13, but a thickness of approximately 0.1 μm to 10 μm is preferred. This makes it possible to improve the printability of the thermal transfer sheet on the transfer target, for example.

[0066] <Back Layer> The back layer 14 is provided on the side (back side) of the substrate 10 opposite to the side on which the transfer layers T1 and T2 are provided, and prevents thermal fusion between the heating device such as a thermal head and the substrate, and ensures smooth movement.

[0067] Examples of resins that form the back layer 14 include polyvinyl butyral, polyvinyl acetal, polyester, vinyl chloride-vinyl acetate copolymer, polyether, polybutadiene, styrene-butadiene copolymer, acrylic polyol, polyurethane acrylate, polyester acrylate, polyether acrylate, epoxy acrylate, urethane or epoxy prepolymer, nitrocellulose resin, cellulose nitrate resin, cellulose acetolpropionate resin, cellulose acetate butyrate resin, cellulose acetate hydrodiene phthalate resin, cellulose acetate resin, polyamide, polyimide, polyamide-imide, polycarbonate, chlorinated polyolefin, and the like.

[0068] The thickness of the back layer 14 is preferably 0.3 μm or more and 5 μm or less, and more preferably 0.5 μm or more and 2 μm or less.

[0069] By transferring the transfer layer T1 or T2 to the object to be transferred 20, information can be added using an identification tag.

[0070] By transferring the transfer layer T1 to the object to be transferred 20 in a predetermined pattern such as a barcode or a two-dimensional code, information can be added via an identification tag along with code information. The code information can be read by a code reader. The reflection pattern read by an optical spectrometer and the code information read by a code reader may be input into a control device (computer) and compared with pre-registered information to perform authentication, identification, and authenticity determination of the item.

[0071] The heat transfer sheet is in the shape of a long strip, and a transfer layer containing an identification tag and a transfer layer without an identification tag may be provided sequentially, that is, repeatedly (alternatingly) along the longitudinal direction of the sheet.

[0072] For example, the thermal transfer sheet S3 may be provided with a transfer layer T1 and a transfer layer T3 having the same configuration as the transfer layer T1 except that it does not include an identification tag, arranged in a face-by-face sequence, as shown in Figure 4. The transfer layer T3 is transferred onto the object to be transferred using a code pattern, and the transfer layer T1 is solid-transferred to another area on the object to be transferred. Solid transfer means transferring so that an area of ​​a predetermined size or larger is completely covered without any gaps. Code information is read from the code printed on the transfer layer T3. The reflective pattern is read from the solid-transferred transfer layer T1. By making the panel area of ​​the transfer layer T1 (the area on which the transfer layer T1 is formed) on the thermal transfer sheet S3 smaller than the panel area of ​​the transfer layer T3, the amount of identification tags used can be reduced.

[0073] A thermal transfer sheet S4 may be provided with a transfer layer T1 and a transfer layer T4 having the same configuration as the transfer layer T2 except that it contains an invisible light absorbing material instead of an identification tag, arranged in a plane order, as shown in Figure 5.

[0074] Invisible light absorbing materials include ultraviolet absorbing materials, infrared absorbing materials, and wavelength conversion materials that are excited by irradiation with invisible light such as ultraviolet or infrared rays and emit visible light. Wavelength conversion materials can include, for example, fluorescent whitening agents that absorb ultraviolet light and emit visible light from purple wavelengths to blue wavelengths (including wavelengths of at least 400 nm to 450 nm), or optical upconversion materials and organic nonlinear optical materials that absorb infrared rays and emit visible light. The transfer layer T4 may contain pearl pigments, holographic pigments, flat interference pigments, glitter pigments, opal pigments, etc., that exhibit interference in visible light with wavelengths of 380 nm to 780 nm.

[0075] By transferring a code pattern onto the transfer layer T1, code information can be added along with information provided by the identification tag. The transfer layer T4 may be a solid transfer or it may be transferred with a code pattern to add code information. The code information from the transfer layer T4 can be read by irradiating the item with invisible light. By further combining the code information from the transfer layer T4, more sophisticated authenticity determination can be achieved.

[0076] A thermal transfer sheet S5 may be provided with a transfer layer T3 and a transfer layer T5 having the same configuration as transfer layer T2 except that an invisible light absorbing material is further added, arranged in a plane order, as shown in Figure 6.

[0077] The transfer layer T3 is transferred using a code pattern, and code information is added. Similarly, the transfer layer T5 is transferred using a code pattern, and code information is added along with information provided by an identification tag. By combining the reflection pattern of the transfer layer T5, read by an optical spectrometer, with the code information of the transfer layers T3 and T5, a more sophisticated authentication method can be achieved. The transfer layer T5 may also be transferred as a solid color.

[0078] The thermal transfer sheet S6 may be one in which transfer layers T1, T3, and T4 are arranged in sequential order on each surface, as shown in Figure 7. Transfer layers T1 and T4 are transferred either as solid transfer or in any shape (such as letters, figures like stars, or those with code information such as barcodes). Transfer layer T3 is transferred with a code pattern. An optical spectrometer reader is used to read the reflection pattern from the transferred transfer layer T1. If the transfer layer T1 is transferred with a code pattern, the code information is read from the printed code. The code information is read from the code printed on the transfer layer T3. Invisible light is shone onto the transfer area of ​​the transfer layer T4, and if the transfer layer T4 is transferred with a code pattern, the code information from the transfer layer T4 is read. By combining the reflection pattern and multiple code information, a more sophisticated authentication method can be used.

[0079] The combination of transfer layers T1 to T5 arranged in a plane sequence on the heat transfer sheet is arbitrary. For example, a first transfer layer (transfer layers T1, T2, T5) containing an identification tag and a second transfer layer (T1, T3, T4, T5) containing at least one of a coloring agent and an invisible light absorbing material can be arranged in a plane sequence. The sizes of the multiple types of transfer layers provided on the heat transfer sheet can be adjusted as appropriate. In the heat transfer sheet S5 shown in Figure 6, the plane sequence of transfer layers T3 and T5 may be vertical, i.e., transfer layer T3 is on top and transfer layer T5 is on the bottom, forming a striped panel arrangement.

[0080] Figure 8 shows a schematic configuration of an authenticity determination system for determining the authenticity of a printed object P manufactured by transferring a transfer layer onto a transfer target. The authenticity determination system comprises a code reader 60, an optical spectrometer reader 62, a determination device 30, and a server 40. The determination device 30 and the server 40 are, for example, computers having a CPU and memory. The determination device 30 and the server 40 may be composed of the same computer.

[0081] For example, the print P has a code pattern 50 onto which the first transfer layers (transfer layers T1, T2, T5) have been transferred. Alternatively, the print P has a code pattern 50 onto which the second transfer layers (T1, T3, T4, T5) have been transferred, and a region 52 onto which the first transfer layer has been solid-colored.

[0082] During the manufacturing of the print P, the information of the reflection pattern of the identification tag contained in the first transfer layer and the code information indicated by the code pattern 50 are combined and registered in the server 40. The server 40 transmits the registered information to the determination device 30.

[0083] The method for determining the authenticity of a print P using this authenticity determination system will be explained according to the flowchart shown in Figure 9.

[0084] The code reader 60 reads the code information from the code pattern 50 of the printed object P and transmits it to the determination device 30 (Step 1). The optical spectrometer reader 62 reads the reflection pattern from the code pattern 50 or region 52 of the printed object P and transmits it to the determination device 30 (Step 2).

[0085] The determination device 30 compares the code information received from the code reader 60 and the reflection pattern received from the optical spectrometer reader 62 with the reflection pattern and code information received from the server 40 and notifies the user of the comparison result (Steps 3 and 4). If the comparison results match, the printed object P is determined to be "genuine," and if the comparison results do not match, the printed object P is determined to be "fake."

[0086] The present disclosure will now be described in more detail with reference to examples, but the present disclosure is not limited to these examples.

[0087] [Example 1-1] A back layer coating liquid with the following composition was applied to one side of a PET film substrate sheet with a thickness of 4.5 μm, and dried to form a back layer with a thickness of 0.3 μm.

[0088] <Coating liquid for back layer> ・Styrene-acrylonitrile copolymer resin 11 parts ・Linear saturated polyester resin 0.3 parts ・Zinc stearyl phosphate 6 parts ・Melamine resin powder 3 parts ・Methyl ethyl ketone 80 parts

[0089] Next, a release layer coating liquid with the following composition was applied to a portion of the surface of the base sheet opposite to the side with the back layer, and dried to form a release layer with a thickness of 0.08 μm. The identification tag used was TruTags (Type 2) manufactured by TruTag Technologies (particle size thickness 3 μm, average particle size 35 μm). The thickness and average particle size of the identification tag were measured using the method for measuring the thickness and average particle size of porous particles described in the above embodiment.

[0090] <Coating liquid for release layer> • Carnauba wax 96.6 parts • Identification tag 3.4 parts • Water 450 parts • IPA 450 parts

[0091] A colored layer with a thickness of 0.08 μm was formed by applying a colored layer coating solution with the following composition to the release layer formed as described above and drying it.

[0092] <Coating liquid for colored layer> ・Carbon black 33.4 parts ・Polyester resin A1 33.3 parts (Mn: 17000, Tg: 67) ・Polyester resin B1 33.3 parts (Mn: 3000, Tg: 53) ・Toluene / methyl ethyl ketone (1 / 1) 900 parts

[0093] On the colored layer formed as described above, an adhesive coating liquid with the following composition was applied and dried to form an adhesive layer with a thickness of 0.1 μm, thereby producing the thermal transfer sheet of Example 1-1.

[0094] <Coating liquid for adhesive layer> • Polyester resin X 100 parts (Mn: 5000, Tg: 70) • Water 450 parts • IPA 450 parts

[0095] [Examples 1-1 to 1-17, Comparative Example 1-1, Examples 2-1 to 2-8, Comparative Example 2-1] Except for changing the composition of the release layer coating liquid, the thickness of the release layer, the composition of the colored layer coating liquid, the thickness of the colored layer, and the thickness B of the identification tag to those shown in Tables 1, 2, and 3, the thermal transfer sheets of Examples 1-1 to 1-17, Comparative Example 1-1, Examples 2-1 to 2-8, and Comparative Example 2-1 were prepared in the same manner as in Example 1-1. The thickness B of the identification tag is the value measured using the porous particle thickness measurement method described in the above embodiment. Comparative Examples 1-1 and 2-1 do not contain an identification tag in either the release layer coating liquid or the colored layer coating liquid.

[0096] The percentage of solids with added identification tags in the transfer layer was calculated using the following formula: Percentage of solids with added identification tags in the transfer layer [%] = Percentage of solids with added identification tags in the identification tag layer [%] × Thickness of the identification tag layer / Thickness A of the transfer layer

[0097] The thickness A of the transfer layer is the sum of the thickness of the release layer, the thickness of the colored layer, and the thickness of the adhesive layer.

[0098] [Missing Identification Tag] Using the thermal transfer sheets and printer (Zebra ZT-610) of each example and comparative example, the transfer layer of the thermal transfer sheet was transferred to the transfer target (Lintec PETWH50(A)PAT1 8LK2) to form a ladder barcode image and obtain a printed object. The transfer conditions were SPEED 6 and TEMPERATURE 16. The surface of the printed object was covered with a cotton cloth at 2.4 N / cm². ２ The cotton cloth was rubbed 20 times back and forth under pressure, and the amount of identification tag transferred was visually determined and evaluated based on the evaluation criteria below. The evaluation results are shown in Tables 1, 2, and 3.

[0099] (Evaluation Criteria) ○: No identification tags observed at all △: A small number of identification tags observed ×: A large number of identification tags observed ―: No identification tags added (as a comparative example)

[0100] [Visibility of Printed Images] Using the thermal transfer sheets obtained in the Examples and Comparative Examples, and a printer (Zebra ZT-610), a ladder barcode image was formed on a substrate (Lintec PETWH50(A)PAT1 8LK2) by transferring the transfer layer of the thermal transfer sheet. The transfer conditions were set to SPEED 6 and TEMPERATURE 16. The formed images were judged using a barcode checker (Honeywell Quick Check 850) and evaluated based on the evaluation criteria below. The evaluation results are shown in Tables 1, 2, and 3.

[0101] (Evaluation Criteria) ○: The barcode checker on the printed material gave an A or B rating. △: The barcode checker on the printed material gave a C rating. ×: The barcode checker on the printed material gave a D rating or was unable to determine the rating.

[0102] [Reading Identification Tags] Reading using an optical spectrometer reader was performed under office lighting conditions on prints created in the [Visibility of Prints] section, using TruTag acquisition software 1.8.1-EX and mode tpp from TruTag Inc., with a smartphone (Samsung Galaxy S9+). Each print was read 10 times and evaluated based on the evaluation criteria below. The evaluation results are shown in Tables 1, 2, and 3.

[0103] (Evaluation Criteria) ○: Identification tags were read 8 or more times out of 10 attempts. △: Identification tags were read 3 to 7 times out of 10 attempts. ×: Identification tags were read 2 or fewer times out of 10 attempts.

[0104]

[0105]

[0106]

[0107] From Tables 1 and 2, it was confirmed that the ratio A / B of the thickness of the transfer layer A to the thickness of the identification tag B is preferably 0.09 to 2.33, and more preferably 0.30 to 1.33. If the transfer layer containing the identification tag is too thick, the identification tag becomes embedded inside, making it difficult to detect the reflection pattern. On the other hand, if the transfer layer is too thin, it cannot hold the identification tag, and the identification tag falls off the transfer layer.

[0108] Table 3 confirms that the amount of identification tag added to the transfer layer is preferably 0.05% to 30% by mass, and more preferably 0.1% to 20% by mass. If the content of identification tag in the transfer layer is too high, the visibility of the printed image decreases. If the visibility of the printed image is low, transferring the transfer layer with a code pattern will lead to poor reading of the code information. On the other hand, if the content of identification tag is too low, the reflection pattern becomes difficult to detect.

[0109] Although this disclosure has been described in detail using specific embodiments, it will be apparent to those skilled in the art that various modifications are possible without deviating from the intent and scope of this disclosure.

[0110] 10 Base material 11 Peeling layer 12 Colored layer 13 Adhesive layer 14 Back layer 20 Transferred object

Claims

1. A thermal transfer sheet comprising: a substrate; and a transfer layer provided on one surface of the substrate and transferred to a transfer target, wherein the transfer layer includes an identification tag having a spectral profile that can be identified in association with predetermined information.

2. The thermal transfer sheet according to claim 1, wherein the spectral profile has a specific reflection pattern or fluorescent X-ray spectrum.

3. The thermal transfer sheet according to claim 2, wherein the reflection pattern has a specific reflection spectrum, reflection peak, or reflection amplitude.

4. The thermal transfer sheet according to claim 3, wherein the identification tag comprises porous particles having pores with a diameter in the nanometer range or an optical effect pigment.

5. The thermal transfer sheet according to claim 4, wherein the porous particles have at least one type of pore selected from the group consisting of (a1) to (a3): (a1) micropores with a diameter of 0.001 nm or more and less than 2 nm, (a2) mesopores with a diameter of 2 nm or more and 50 nm or less, and (a3) ​​macropores with a diameter greater than 50 nm and 1000 nm or less.

6. The thermal transfer sheet according to claim 4, wherein the average particle size of the porous particles is 10 μm or more and 150 μm or less.

7. The thermal transfer sheet according to claim 4, wherein the porous particles are plate-shaped or scale-shaped.

8. The thermal transfer sheet according to claim 7, wherein the thickness of the porous particles is 0.1 μm or more and 10 μm or less.

9. The thermal transfer sheet according to claim 4, wherein the porous particles are porous silica particles.

10. The thermal transfer sheet according to claim 1, wherein the ratio A / B of the thickness A of the transfer layer to the thickness B of the identification tag is 0.09 or more and 2.33 or less.

11. The thermal transfer sheet according to claim 1, wherein the amount of the identification tag added to the transfer layer is 0.05% by mass or more and 30% by mass or less.

12. The thermal transfer sheet according to claim 1, wherein the transfer layer contains at least one of a coloring agent and an invisible light absorbing material.

13. The heat transfer sheet according to claim 1, wherein the transfer layer comprises a first transfer layer and a second transfer layer, the first transfer layer and the second transfer layer are sequentially and repeatedly provided along the longitudinal direction of the heat transfer sheet, the first transfer layer contains the identification tag, and the second transfer layer contains at least one of a coloring agent and an invisible light absorbing material.

14. A method for manufacturing a printed object, comprising heating a heat transfer sheet according to claim 1, 12, or 13 and transferring the transfer layer onto a transfer object to produce a printed object.

15. The method for manufacturing a printed object according to claim 14, wherein the object to be transferred is a label.

16. A method for manufacturing a printed object, comprising heating the heat transfer sheet described in claim 12 and transferring the transfer layer onto a transfer object in a predetermined code pattern to produce a printed object.

17. A method for manufacturing a printed object, comprising heating the heat transfer sheet according to claim 13, transferring the first transfer layer onto a transfer target, and transferring the second transfer layer onto the transfer target in a predetermined code pattern.

18. A method for determining authenticity of a printed object, comprising: using a code reader to read code information from the code pattern formed on a printed object manufactured by the method for manufacturing a printed object according to claim 16; using an optical spectrometer to read a reflection pattern from the code pattern on the printed object; comparing the code information and the reflection pattern with predetermined information; and determining the authenticity of the printed object.

19. A method for determining the authenticity of a printed object, comprising: using a code reader to read code information from the code pattern of the second transfer layer formed on a printed object manufactured by the method for manufacturing a printed object according to claim 17; using an optical spectrometer to read a reflection pattern from the area on which the first transfer layer has been transferred; comparing the code information and the reflection pattern with predetermined information; and determining the authenticity of the printed object.

20. A genuineness determination system comprising: a code reader for reading code information from a code pattern formed on a printed object manufactured by the method for manufacturing a printed object according to claim 16; an optical spectrometer for reading a reflection pattern from the code pattern on the printed object; and a determination device for comparing the code information and the reflection pattern with predetermined information to determine the authenticity of the printed object.

21. A genuineness determination system comprising: a code reader for reading code information from the code pattern of the second transfer layer formed on a printed object manufactured by the method for manufacturing a printed object according to claim 17; an optical spectrometer for reading a reflection pattern from the region on which the first transfer layer has been transferred; and a determination device for comparing the code information and the reflection pattern with predetermined information to determine the authenticity of the printed object.

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