JP7567340B2 - Thermal transfer medium and information recording medium - Google Patents

Description

The present invention relates to a thermal transfer medium for producing personal authentication media such as passports and ID cards, as well as an information recording medium using the same and a method for producing the same.

Various security methods have been proposed for personal authentication information recording media such as passports, visa stickers, and cards. Commonly used security features include chemical reactants that react with organic solvents, iridescent pearl chips, fibers (silk or synthetic, visible or invisible, fluorescent or non-fluorescent), security threads made of film printed with holograms or micro-characters, paper incorporating watermarks, and a variety of inks such as fade-resistant ink, fluorescent ink, heat-sensitive ink, and optically variable ink (so-called OVI, etc.), fine line printing, rainbow printing, intaglio printing, pixel printing, and other techniques that simultaneously improve security and aesthetics.

As a means of making it possible to carry out identification using simple equipment, it has been proposed to use a conventional printing technique such as offset printing to print a colorless fluorescent ink containing a fluorescent substance onto a card to form a latent image (Patent Document 1). However, this method is only suitable for forming a common latent image for a certain type of card, and is good for identifying whether the card base material being used is genuine, but in order to be able to determine whether the content displayed on the issued card is genuine, it is necessary to create a printing plate for each card, which is not practical.

The widespread use of color copiers, scanners, and color laser printers has made it easy to make highly accurate copies. A typical color digital copier uses a CIS (Contact Image Sensor) to convert the original into a color digital signal, and can reproduce color images using yellow (Y), magenta (M), cyan (C), and black (Bk) toners.

To deal with this issue, colors that cannot be reproduced with the toner of a color digital copier are printed to make it difficult to reproduce the color in the copy. For example, green, purple, orange, gold, silver, etc. are printed to make it difficult to reproduce the color in the copy. Furthermore, photoluminescent materials with interference colors are printed to make copying with a color digital copier even more difficult. However, photoluminescent materials with interference colors are used as pearl pigments in cosmetics and wrapping paper, and are accessible to the general public, so if the pattern is simple, it may be relatively easy to reproduce, and the security is not sufficient.

Means under consideration for recording images such as face photographs as visual confirmation information on ID cards include thermal transfer recording using transfer ribbons that use dye-sublimation (thermotransfer) dyes or resin-type melting or wax-type transfer ribbons with pigments dispersed therein, as well as electrophotography. Printers using thermal transfer recording or electrophotography can easily record individual information for each medium, but considering that they are now widely used, it is possible to forge or counterfeit by forming a new image in the area after removing the face photograph or other image, so this alone does not provide sufficient security.

To solve the above problems, methods have been considered that include multiple pieces of information to identify an individual in addition to a facial photograph. One method involves adding digital watermark information to a facial photograph, storing that information on an IC chip in the same medium, and authenticating the individual by comparing the digital watermark information with the information on the IC chip (see, for example, Patent Document 2). Another method involves converting the feature points of the facial photograph information into numerical values, converting that value into a two-dimensional code, printing it on the same medium, and authenticating the individual by comparing the data of the two-dimensional code with the feature points of the facial photograph (see, for example, Patent Document 3).

However, each of the above methods requires a dedicated decoder to read the facial photograph, IC chip, or two-dimensional code, and there is a problem that authentication is only possible for people who own the reading device and decoder. Another possible verification method is to insert multiple facial photographs that allow authentication by visual information. In addition to the facial photographs provided by the above methods, there is a method of forming the same facial photograph using fluorescent material (see, for example, Patent Document 4, Patent Document 5, and Patent Document 6). However, the above methods that use fluorescent material require the use of an ultraviolet lamp (black light), so authentication is only possible in limited situations.

Patent Document 7 discloses an ink ribbon, which is a thermal transfer medium, in which color panels of yellow (Y), magenta (M), and cyan (C) and security panels of red (R), green (G), and blue (B) formed with holograms are formed on the same film. However, the color panels and the hologram security panels cannot be formed at the same time, and separate processes are required, which inevitably results in high costs.

Patent Document 7 also discloses an image display in which an image is formed using a hologram ribbon that exhibits red (R), green (G), and blue (B) at a specific viewing angle due to the hologram. However, there are problems with holograms, such as the structure collapsing during thermocompression bonding to a recording medium, which can cause image distortion, whitening due to heat, and limited use environments.

As another configuration, there are also those that exert an anti-counterfeiting effect by using an optically variable element such as a hologram provided in the middle layer of the intermediate transfer medium. The three-dimensional images and color changes expressed by holograms and the like have the advantage of being highly decorative and difficult to counterfeit, but there is also the issue that when something that appears to have a similar effect is used instead, it is difficult to distinguish the authenticity by visual inspection unless one is an expert in authenticity judgment.

Utility Model Registration No. 3029273 JP 2001-126046 A JP 2004-70532 A Japanese Patent Application Publication No. 7-125403 JP 2000-141863 A JP 2002-226740 A Patent No. 5569106

The present invention was made in consideration of these problems, and aims to provide a thermal transfer medium and information recording medium that can manufacture security ink panels in the same process as normal color ink panels, can determine whether the information printed on each information recording medium is genuine, and can record highly secure patterns individually on demand, providing a high level of counterfeit prevention.

In order to solve the above problem, one aspect of the present invention is
A thermal transfer medium having ink panels of multiple colors of thermal transfer inks applied in a surface-sequential manner on a support, the ink panels having at least black, cyan, magenta, and yellow color ink panels, three photoluminescent ink panels exhibiting red, green, and blue structural colors using photoluminescent ink, and an adhesive layer panel , which are applied in this order, and at least one of the photoluminescent ink panels contains a fluorescent agent, which, when irradiated with ultraviolet light, exhibits a color equivalent to the structural color exhibited by the photoluminescent ink of the photoluminescent ink panel containing the fluorescent agent .

In the above-described thermal transfer medium, the glittering ink may contain a glittering pigment having a synthetic mica core, which is coated with titanium oxide (TiO ₂ ) and then coated with iron oxide (Fe ₂ O ₃ ).

In the above-mentioned thermal transfer medium, the glittering ink may contain a glittering pigment having a synthetic mica core, which is coated with silicon oxide (SiO ₂ ) and then coated with iron oxide (Fe ₂ O ₃ ).

Another aspect of the present invention is
This is an information recording medium characterized in that a visual image pattern transferred from the color ink panel and a glitter pattern transferred from the glitter ink panel are formed by any of the above-mentioned thermal transfer media, and individual information is formed in the glitter pattern by at least one type of glitter ink.

According to the present invention, a thermal transfer medium is obtained in which a normal color ink panel and an ink panel of red, green, and blue photoluminescent inks are formed, and a normal visual image pattern and a security pattern that combines multiple photoluminescent inks containing photoluminescent pigments can be formed on an information recording medium on demand. The security pattern is difficult to copy using a normal color copier, and can be made to look in different colors when viewed from the front and when viewed at an angle, so that it can be easily determined that the information recording medium is genuine by changing the viewing angle, providing an anti-counterfeiting effect for the information recording medium and enabling authenticity determination.

Furthermore, by using a thermal transfer medium with photoluminescent ink containing a fluorescent agent, the difficulty of ribbon production increases, and personal information can be verified not only under visible light but also under ultraviolet light, providing two levels of security.

1 is a schematic diagram illustrating an example of a heat-sensitive transfer medium of the present invention. FIG. 1 is a schematic diagram showing an example of a printer for forming an information recording medium of the present invention. FIG. 2 is a schematic diagram showing an example of an information recording medium issued in the present invention. 2 is a cross-sectional view of an information recording medium according to an embodiment of the present invention taken along line XX'. FIG. 1A to 1C are schematic diagrams showing an example of changes in security information when an information recording medium in an embodiment of the present invention is tilted and when it is irradiated with ultraviolet light (UV light).

Hereinafter, an embodiment of the present invention will be described in detail with reference to the drawings. Note that the present invention is not limited to the embodiment described below. In addition, in the embodiment described below, technically preferable limitations are imposed for carrying out the invention, but these limitations are not essential requirements for the present invention. Note that, in the following, the same reference numerals may be used to designate equivalent members, and their description may be omitted.

Figure 1 is a schematic diagram showing an example of the thermal transfer medium of the present invention. The thermal transfer medium 1 is formed by applying a plurality of thermal transfer ink panels in the longitudinal direction on a support 2 in a surface-sequential manner. The thermal transfer ink panels are formed of four color ink panels of black K, cyan C, magenta M, and yellow Y, a photoluminescent ink panel showing red R, green G, and blue B by photoluminescent ink, and an adhesive layer panel 3. The size of each panel can be appropriately set according to the specifications of the recording size of the information recording medium to be finally recorded. In addition, a sensor mark S may be provided as necessary. In addition, a backcoat layer such as a heat-resistant layer or a slippery layer may be provided on the side of the support 2 opposite to each ink panel.

With a thermal transfer medium 1 configured in this way, it is easy to first form a color image and a character image on the intermediate transfer medium using four color inks, black K, cyan C, magenta M, and yellow Y, using an indirect transfer recording device, and then transfer a security pattern using photoluminescent inks of red R, green G, and blue B. Furthermore, by transferring an adhesive layer, it is possible to ensure that the transfer to the information recording medium, which is the transfer target, can be performed reliably.

Each thermal transfer ink panel can be formed by the same process as a general thermal transfer medium, for example, gravure printing. Thermal transfer medium 1 at least has panels of K/C/M/Y/R/G/B//adhesive layer in sequence as described above, with K/C/M/Y being the ink panel that forms a normal visual image pattern and R/G/B being the photoluminescent ink panel that forms a security pattern. The thermal transfer medium of the present invention can be used in an intermediate transfer recording method, and adhesive layer panel 3 is an adhesive panel for adhering the transferred surface of the information recording medium to the image pattern when the image pattern consisting of the visual image pattern and the security pattern transferred to the intermediate transfer medium in the primary transfer process is retransferred to the information recording medium in the secondary transfer process.

The glittering pigment used in the glittering ink is a material in which synthetic mica is used as a core, and is coated with titanium oxide (TiO ₂ ) or silicon oxide (SiO ₂ ), and then coated with iron oxide (Fe ₂ O ₃ ). Titanium oxide (TiO ₂ ) and silicon oxide (Fe ₂ O ₃ ) produce a structural color effect, and unlike synthetic mica simply coated with iron oxide (Fe ₂ O ₃ ), when tilted, it shows a color according to the wavelength of the reflected light. For example, if the core of synthetic mica is coated with titanium oxide (TiO ₂ ) and then coated with iron oxide (Fe ₂ O ₃ ), when viewed almost from the front, there is almost no interference color and it appears reddish brown, which is the color of iron oxide. When viewed from a direction of about 30 degrees, the interference color becomes visible and it can be made to appear green, and when viewed from a direction of about 60 degrees, it can be made to appear blue.

The structural color effect of photoluminescent pigments is determined by the thickness of the coating of titanium oxide or silicon oxide and the refractive index of the coating material, so when tilted, they will show a color that corresponds to the wavelength of the reflected light. In other words, which color will be shown when viewed from which angle can be determined by designing and creating the product by controlling the amount of coating so that the optical path length (red R, green G, blue B) corresponds to the wavelength of the required color, so it can be set appropriately.

The fluorescent agent added to the photoluminescent ink panel can be any luminescent material that is invisible under visible light, i.e., white or transparent, and emits light in the visible light range when irradiated with special light such as ultraviolet light. For example, a fluorescent agent that is excited with energy and emits red light when irradiated with ultraviolet light, or a fluorescent agent that is excited with energy and emits blue light when irradiated with ultraviolet light, etc. can be used, but is not limited to these. The fluorescent agent added to the photoluminescent ink panel can be the same color as the photoluminescent pigment of the photoluminescent ink panel, or a different color. By using a fluorescent agent that emits the same color as the photoluminescent pigment, the fluorescent agent will emit the same color as the photoluminescent pigment when irradiated with ultraviolet light, making it possible to create a full-color image. In addition, by using a photoluminescent pigment mixed with a fluorescent agent, the effect of preventing counterfeiting is further enhanced.

By incorporating security information such as the personal information of the holder of the information recording medium using photoluminescent ink and printing this information on demand (variable), it is possible to further prevent counterfeiting and make it easier to determine authenticity. The pattern of the security information can take any form, including characters, images, symbols, and figures. In addition, personal information, which undergoes optical changes, can be confirmed simply by tilting the information recording medium, and since no special equipment is required for confirmation, confirmation can be easily performed in any situation.

Conventionally, holograms have been used as security features, but the process for processing them into a thermal transfer medium is different from that of color inks (yellow Y, magenta M, cyan C, black K). For example, color ink panels are formed by coating a substrate, whereas holograms require many complicated processes, such as a coating process for a reflective layer on the substrate, a deposition process for a deposition layer, and an embossing process. It is necessary to coat a hologram-processed film with color inks, or to process a hologram on a film coated with color inks, which makes alignment difficult. In contrast, the formation of ink panels of red R, green G, and blue B using the photoluminescent ink of the present invention can be formed at the same time as the color inks are coated, and the processing process is simple and alignment can be performed during the normal coating process, so there is no need to make it a separate process. Color ink panels (yellow Y, magenta M, cyan C, black K) and photoluminescent ink panels (red R, green G, blue B) can be formed sequentially in a series of coating processes, and one thermal transfer medium (thermal transfer ribbon) can be inexpensively produced.

When using fluorescent photoluminescent ink, it is possible to simply mix the fluorescent agent according to the application when preparing the ink, and the thermal transfer medium can be formed in the same manner as described above. Examples of phosphors that can be dispersed in the binder include blue phosphors such as perylene, 1,1,4,4-tetraphenyl-1,3-butadiene, and poly(9,9-dialkylfluorene); green phosphors such as coumarin dyes, quinacridone dyes, poly(p-phenylenevinylene), and poly(fluorene); and red phosphors such as 4-dicyanomethylene-4H-pyran derivatives, 2,3-diphenylfumaronitrile derivatives, and coumarin dyes.

The binder resin used in each ink panel can be any substantially transparent thermoplastic resin, such as acrylic resin, styrene resin, polyester resin, epoxy resin, vinyl resin, rosin resin, polyamide resin, etc., but is not limited to these. Each thermoplastic resin can be used alone or as a mixture, or even as a composite such as a copolymer.

Examples of thermoplastic resins used in the adhesive layer panel 3 include, but are not limited to, acrylic resins, polyester resins, polyurethane resins, polyamide resins, vinyl resins such as polyvinyl chloride and vinyl chloride-vinyl acetate copolymers, chlorinated polyolefins, ethylene-acrylic copolymers, epoxy resins, and rosin resins. These thermoplastic resins can be used alone or as a mixture or composite of two or more. Depending on the situation, waxes and the like may be added in addition to inorganic fillers and organic fillers.

Figure 2 is a schematic block diagram of an example of an indirect transfer recording device for producing the information recording medium of the present invention. The information recording medium of the present invention can be produced by a thermal transfer printer using the above-mentioned thermal transfer medium. Figure 6 shows an example of a thermal transfer printer configured as an indirect transfer type printer. In the indirect transfer recording device 100, the thermal transfer medium 1 is unwound from the unwinding roll 5, passes between the thermal head 7 and the platen roller 12 of the primary transfer section 101 where thermal transfer printing is performed on the intermediate transfer film 8, and is wound up on the winding roll 6. The intermediate transfer film 8 is also unwound from the unwinding roll 9, passes between the thermal head 7 and the platen roller 12 of the primary transfer section 101, passes between the heat roller 11 and the platen roller 12 of the primary transfer section 101, and is wound up on the winding roll 10 in the secondary transfer section 102 where thermal pressure transfer is performed on the transferee 13.

In the primary transfer section 101, a color image, a pattern such as a character, etc. is transferred from the four ink panels of black K, cyan C, magenta M, and yellow Y from the thermal transfer medium 1 onto the overlay layer, which also serves as the image receiving layer of the intermediate transfer film 8, and a glittering pattern is transferred from the three ink panels of red R, green G, and blue B, which use glittering pigments as coloring materials. Next, the adhesive layer panel 3 is further superimposed and transferred over the entire area to be transferred to the transferee 12 such as a card. The intermediate transfer film 8 on which each pattern is formed is transported to the secondary transfer section 102, and is thermally and pressure-bonded to the transferee 13 by the heat roller 11, so that each pattern formed in the primary transfer section 101 is transferred to the transferee 13 together with the overlay layer. Both the color image, the pattern such as a character, and the glittering pattern can be made into any pattern by appropriately controlling the thermal head 7, and any individual information can be formed on the intermediate transfer film 8 and the transferee 13.

Figure 3 is a plan view of one embodiment of the information recording medium of the present invention on which each image pattern is formed as described above. The information recording medium 13 is typically in the form of a card such as an ID card, but may also be in the form of a sheet or booklet, and is not particularly limited as long as it has a flat recording surface. On the information recording medium 13, a color image pattern 14 formed by transferring from ink panels of four colors, black K, cyan C, magenta M, and yellow Y, a pattern 16 such as letters, and a photoluminescent pattern 15 transferred from an ink panel of three types of photoluminescent inks containing photoluminescent pigments of red R, green G, and blue B as coloring materials are formed.

Figure 4 shows an example of a cross section of an information recording medium on which each image pattern is formed, cut along line segment X-X'. The example shown in Figure 4 is an information recording medium 13 on which a glittering pattern 15 is formed by an indirect transfer recording method using the thermal transfer medium 1 shown in Figure 1. The information recording medium 13 has a color image pattern 14 transferred from the thermal transfer medium 1 to an intermediate transfer film, a pattern 16 of characters, etc., a glittering pattern 15 transferred from a glittering ink using a glittering pigment as a coloring material, and an adhesive layer panel 3 transferred onto a substrate 12 together with an overlay layer 17 of the intermediate transfer film. A primer layer or the like may be provided in advance on the substrate 12 to enhance adhesion to the adhesive layer panel 3.

The top diagram in Figure 5 shows the information recording medium 13 shown in Figure 3 as viewed from the front under normal conditions. At this time, the glittering pattern 15a onto which the glittering ink has been transferred appears as a monochrome pattern of reddish brown, which is the color of iron oxide, with no visible interference color.

When this information recording medium 13 is viewed tilted at, for example, about 30 degrees as shown in the middle diagram of Figure 5, the photoluminescent pattern 15b appears as a full-color image with interference colors of red R, green G, and blue B appearing according to the transferred photoluminescent ink. Therefore, by switching between viewing it from the front and tilted at about 30 degrees, the photoluminescent pattern can be viewed as either a single color or full color, and can be used as a security function to determine authenticity. In this case, the photoluminescent pattern 15 is not limited to a facial image as shown in the example, but can be a pattern of any individual information, such as a name or ID number.

Also, an example of the case where a fluorescent agent is contained in the glittering ink panel is shown in the lower part of Fig. 5. When ultraviolet light is irradiated from the ultraviolet light source 18, the area containing the fluorescent agent emits fluorescence. For example, if a fluorescent agent that emits red light is contained in the red glittering ink panel, a fluorescent agent that emits green light is contained in the green glittering ink panel, and a fluorescent agent that emits blue light is contained in the blue glittering ink panel, when ultraviolet light is irradiated, the part of the glittering pattern 15c where the red glittering ink panel is transferred emits red light, the part where the green glittering ink panel is transferred emits green light, and the part where the blue glittering ink panel is transferred emits blue light. As a result, the glittering pattern 15c appears as a full-color image, similar to the example shown in the middle part of Fig. 5.

The presence of a pattern made of photoluminescent ink can be confirmed by changing the angle of the information recording medium 13, which causes a color change, but the effect of the fluorescent agent is not noticeable until it is exposed to ultraviolet light. Generally, security features are considered more secure if their presence is not obvious, so this has the effect of further enhancing security.

As described above, the thermal transfer medium of the present invention allows a lustrous pattern containing individual information to be formed on an information recording medium, and by changing the angle at which the information recording medium is viewed, the lustrous pattern containing the individual information can be easily switched between appearing in a single color and appearing as a full-color image. It can also be made to appear as a luminous pattern when exposed to ultraviolet light, and by using this as a security feature, it can be highly effective in verifying authenticity and preventing counterfeiting.

In addition, by using the thermal transfer medium of the present invention, since a normal color ink panel and a glitter ink panel are integrated into a single thermal transfer medium, an information recording medium with a security pattern can be printed on demand using a normal thermal transfer printer.

In addition, when the thermal transfer medium (thermal transfer ribbon) of the present invention reproduces the desired colors (red R, green G, blue B) using photoluminescent ink, it does not form a structure by embossing like a hologram, so the structure does not collapse or whiten due to heat and pressure, and the reproduction of the desired colors is not impaired even when it is heat-pressed.

The heat-sensitive transfer medium of the present invention can be printed using a photoluminescent ink panel containing a photoluminescent pigment with structural color, allowing a photoluminescent ink pattern containing individual information to be created on demand, and simply tilting the information recording medium changes color, making it possible to easily and quickly determine whether the information has been forged or altered. Furthermore, by using photoluminescent ink mixed with a fluorescent agent as the heat-sensitive transfer medium, authentication can also be performed under ultraviolet light, allowing for two-stage authentication.

The photoluminescent ink panel used in the thermal transfer medium of the present invention is of a color that cannot be reproduced by the toner of a color digital copier, making it difficult to copy, and furthermore, by using a photoluminescent pigment having an interference color, it becomes even more difficult to copy and reproduce by a color digital copier. That is, the photoluminescent pigment used in _the present invention is a material that has a synthetic mica core, is coated with titanium oxide ( _TiO2 ) or silicon oxide ( _SiO2 ), and is then coated with iron oxide ( _Fe2O3 ), and when the information recording medium is tilted, the photoluminescent ink pattern part changes color from reddish brown to each interference color, making it difficult to copy, and furthermore, by using a photoluminescent pigment containing a fluorescent agent, the structure can be made more complex and security can be improved.

Example 1
(Preparation of thermal transfer medium)
A color ink panel containing each of the pigments of black K, cyan C, magenta M, and yellow Y, a glittering ink panel consisting of security ink 1 containing a glittering pigment of red R, security ink 2 containing a glittering pigment of green G, and a glittering ink panel consisting of security ink 3 containing a glittering pigment of blue B, and an adhesive layer panel were sequentially formed on one side of a 4.5 μm polyethylene terephthalate (PET) substrate as a support by a gravure coater using a mixed resin obtained by mixing various pigments with a polyester resin, and the color material panel had a thickness of 1.0 μm, the glittering ink panel had a thickness of 1.2 μm, and the adhesive layer panel had a thickness of 1.2 μm, to form a thermal transfer medium. A backcoat layer was also provided on the opposite side of the PET substrate.
[Cyan Ink Composition]
Cyan pigment: 5 parts by weight Vylon 500 (Toyobo Co., Ltd.) 15 parts by weight MEK (Toyo Ink Mfg. Co., Ltd.) 80 parts by weight [Magenta ink composition]
Magenta pigment: 5 parts by weight Vylon 500 (Toyobo Co., Ltd.) 15 parts by weight MEK (Toyo Ink Mfg. Co., Ltd.) 80 parts by weight [Yellow ink composition]
Yellow pigment: 5 parts by weight Vylon 500 (Toyobo Co., Ltd.) 15 parts by weight MEK (Toyo Ink Mfg. Co., Ltd.) 80 parts by weight [Composition of black ink]
Carbon black pigment: 5 parts by weight Vylon 500 (Toyobo Co., Ltd.) 15 parts by weight MEK (Toyo Ink Mfg. Co., Ltd.) 80 parts by weight [Composition of security ink 1]
Red brilliant pigment: 5 parts by weight Vylon 500 (Toyobo Co., Ltd.) 15 parts by weight MEK (Toyo Ink Mfg. Co., Ltd.) 80 parts by weight [Composition of security ink 2]
Green brilliant pigment: 5 parts by weight Vylon 500 (Toyobo Co., Ltd.) 15 parts by weight MEK (Toyo Ink Mfg. Co., Ltd.) 80 parts by weight [Composition of Security Ink 3]
Blue brilliant pigment: 5 parts by weight Byron 500 (Toyobo Co., Ltd.) 15 parts by weight MEK (Toyo Ink Mfg. Co., Ltd.) 80 parts by weight

The lustrous pigment used in the lustrous ink panel is synthetic mica (synthetic glass) coated with titanium oxide ( _TiO2 ) that exhibits the desired interference colors (red R, green G, blue B) when tilted, and is further coated with iron oxide ( _Fe2O3 ) after being coated with titanium oxide ( _TiO2 ) so that when the panel is not tilted, it exhibits the reddish brown color of _iron oxide ( _{Fe2O3 )} .

(Preparation of intermediate transfer medium)
An epoxy resin was applied as an overlay layer to a thickness of 0.8 μm on one side of a 12 μm polyethylene terephthalate (PET) substrate by a gravure coater to obtain an intermediate transfer medium.
[Ink Composition of Overlay Layer]
jER1003 (Mitsubishi Chemical Corporation) 20 parts by weight MEK (Toyo Ink Mfg. Co., Ltd.) 80 parts by weight

An information recording medium was created by the intermediate transfer method using the above-mentioned thermal transfer medium and intermediate transfer medium. A card printer CP500 (manufactured by Toppan Printing Co., Ltd.) was used as the printer, and a card was used as the information recording medium. The intermediate transfer medium and thermal transfer medium were placed opposite each other, and heat was applied to the thermal transfer medium using a thermal head, and a color ink layer, a photoluminescent ink layer, and an adhesive layer were printed on the overlay layer of the intermediate transfer medium in that order. The overlay layer, color ink layer, and photoluminescent ink layer were then thermally transferred by a heat roller onto the surface of the information recording medium via the adhesive layer, thereby obtaining an information recording medium.

The first image forming section is formed by color images and character images formed by each color of the color ink panel, and the second image forming section is formed by a photoluminescent ink panel and is arranged for printing.

Example 2
(Preparation of thermal transfer medium)
On one side of a 4.5 μm polyethylene terephthalate (PET) substrate as a support, a color ink panel containing each dye of black K, cyan C, magenta M, and yellow Y, a glittering ink panel consisting of security ink 4 containing a glittering pigment of red R, security ink 5 containing a glittering pigment of green G, and security ink 6 containing a glittering pigment of blue B, and an adhesive layer panel were successively formed using a gravure coater with a mixed resin obtained by mixing various pigments with a polyester resin, and the color ink panel had a thickness of 1.0 μm, the glittering ink had a thickness of 1.2 μm, and the adhesive layer panel had a thickness of 1.2 μm, to form a thermal transfer medium. A backcoat layer was also provided on the opposite side of the PET substrate.

[Cyan Ink Composition]
Cyan pigment: 5 parts by weight Vylon 500 (Toyobo Co., Ltd.) 15 parts by weight MEK (Toyo Ink Mfg. Co., Ltd.) 80 parts by weight [Magenta ink composition]
Magenta pigment: 5 parts by weight Vylon 500 (Toyobo Co., Ltd.) 15 parts by weight MEK (Toyo Ink Mfg. Co., Ltd.) 80 parts by weight [Yellow ink composition]
Yellow pigment: 5 parts by weight Vylon 500 (Toyobo Co., Ltd.) 15 parts by weight MEK (Toyo Ink Mfg. Co., Ltd.) 80 parts by weight [Composition of black ink]
Carbon black pigment: 5 parts by weight Byron 500 (Toyobo Co., Ltd.) 15 parts by weight MEK (Toyo Ink Mfg. Co., Ltd.) 80 parts by weight [Composition of security ink 4]
Red brilliant pigment: 5 parts by weight Fluorescent agent A: 3 parts by weight Vylon 500 (Toyobo Co., Ltd.) 15 parts by weight MEK (Toyo Ink Mfg. Co., Ltd.) 80 parts by weight [Composition of security ink 5]
Green brilliant pigment: 5 parts by weight Fluorescent agent B: 3 parts by weight Byron 500 (Toyobo Co., Ltd.) 15 parts by weight MEK (Toyo Ink Mfg. Co., Ltd.) 80 parts by weight [Composition of security ink 6]
Blue photoluminescent pigment: 5 parts by weight Fluorescent agent C: 3 parts by weight Byron 500 (Toyobo Co., Ltd.): 15 parts by weight MEK (Toyo Ink Mfg. Co., Ltd.): 80 parts by weight Photoluminescent ink: Security inks 4, 5, and 6 used in the panels are invisible, i.e., white or transparent, and contain fluorescent agents A, B, and C, respectively, which are energy excited and emit the desired luminescent color when irradiated with ultraviolet light.
The other materials are the same as those in the first embodiment.

(Intermediate Transfer Medium)
The same intermediate transfer medium as in Example 1 was used.

Using the above thermal transfer medium and intermediate transfer medium, cards containing information were printed using the card printer CP500, in the same manner as in Example 1.

Example 3
Using the same thermal transfer medium and intermediate transfer medium as in Example 1, the primary transfer was carried out with a CP500 printer, after which the intermediate transfer film was removed and a card was formed by heat and pressure using a general card laminator.

From Examples 1, 2, and 3, the following effects were confirmed.
- Using gravure printing, which is the same process as forming the general thermal transfer media of yellow (Y), magenta (M), cyan (C), and black (K), it was possible to form the red R, green G, and blue B photoluminescent ink panels, which are security ink panels using photoluminescent ink, on the substrate, making it easy to integrate the color ink panels and the photoluminescent ink panels.
- By using it as a thermal transfer medium, it was possible to form images, characters, figures, etc. suitable for on-demand recording.
- Personal authentication under visible light: When the card was tilted, the second image formed area printed using the photoluminescent ink panel was confirmed to change color from reddish brown to full color as a single image.
- Personal authentication under ultraviolet light: In Example 2, when a fluorescent agent was contained in the photoluminescent ink panel, when exposed to ultraviolet light, the second image forming area printed using the photoluminescent ink panel emitted light as a full-color image, and a color change was confirmed.
In Example 3, generally, in the case of a hologram image, whitening and image distortion occurred due to heat and pressure of 130°C or higher. However, the second image forming section using a photoluminescent pigment did not change due to heat and pressure bonding, and it was confirmed that tilting the personal authentication medium caused a color change similar to that in Example 1.
Based on the above, it was possible to produce a thermal transfer medium with new security features using the same processing steps as for normal thermal transfer media, and when used as a personal authentication medium, it was possible to achieve complex anti-counterfeiting effects.

1...thermal transfer medium 2...support K...black C...cyan M...magenta Y...yellow R...red G...green B...blue 3...adhesive layer panel 4...thermal transfer medium unwinding section 5...thermal transfer medium winding section 6...thermal head 7...intermediate transfer medium 8...intermediate transfer medium unwinding section 9...intermediate transfer medium winding section 10...heat roll 11...platen roll 12...substrate 13...information recording body 14...color image pattern 15...photoluminescent patterns 15a, 15b, 15C...photoluminescent pattern 16...pattern of characters, etc. 17...overlay 18...ultraviolet light source

Claims (4)

A thermal transfer medium comprising a support and ink panels of a plurality of colors of thermal transfer inks applied in a surface-sequential manner, the ink panels including at least color ink panels of black, cyan, magenta, and yellow, three glitter ink panels each having a structural color of red, green, and blue using glitter ink, and an adhesive layer panel, the ink panels being applied in this order;
At least one of the glittering ink panels contains a fluorescent agent, and the fluorescent agent exhibits a color equivalent to a structural color exhibited by the glittering ink of the glittering ink panel containing the fluorescent agent when irradiated with ultraviolet light.
Thermal transfer media. 2. The thermal transfer medium according to claim 1, wherein the glittering ink contains a glittering pigment having a synthetic mica core, which is coated with titanium oxide ( _TiO2 ) and then with iron _oxide ( _Fe2O3 ). 3. The thermal transfer medium according to claim 1, wherein the glittering ink contains a glittering pigment having a synthetic mica core, which is coated with silicon oxide ( _SiO2 ) and then with iron _oxide ( _Fe2O3 ). 4. An information recording medium comprising: a visual image pattern transferred from the color ink panel; and a glitter pattern transferred from the glitter ink panel, the visual image pattern being formed by the thermal transfer medium according to claim 1 ; and individual information being formed in the glitter pattern by at least one type of glitter ink.