JPH09305725A - Illegal usage preventing and detecting method for information recording material - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a method effective for optically detecting the state of image receiving layer of information record, etc., and for preventing forgery or revise caused by forming a protection layer into a recording part. SOLUTION: Concerning an information recording material for which the image receiving layer composed of thermoplastic resin is provided on a base composed of resin or paper and the surface of the image receiving layer is painted in optically different colors so as to be mutually distinguished, formed with characters, patterns or images, made opaque or processed while combining these operations, when recording the information of images, characters or symbols on such a material, the state of surface of the image receiving layer or the base is optically detected.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a fraud prevention and fraud detection method for a card or the like by performing specific processing on the card or the like. More specifically, the present invention relates to a method effective for optically detecting the state of the image receiving layer at the time of recording information and for preventing alteration or falsification by forming a protective layer on the recording portion.

[0002]

2. Description of the Related Art In recent years, due to the widespread use of telephone cards, credit cards, tickets, prepaid cards, etc., and the conversion of commuter tickets and tickets to magnetic cards, it has been possible to use securities, certificates, ID cards and licenses. Countermeasures against forgery, which has been a problem, are required for these cards, and various measures are being taken. Various contrivances have been made to the software for recording and decoding for tampering with magnetic recording, which is often caused by counterfeiting or falsification of cards, but the reality is that there is no deciding effective because of the characteristic of rewritable magnetic recording. In addition, the punched holes showing the usage status are also modified so that the holes are cleverly closed, and measures to prevent the modification are urgently needed. The method of using an IC such as an IC card, which is a key factor in preventing forgery, alteration, and falsification, has a limited range of use because the card becomes thick due to the cost and the thickness of the IC itself. The ink used for printing on these cards, banknotes, printed matters such as securities, and bar codes has been devised to prevent forgery. A method is used in which ink mixed with magnetic powder, fluorescent ink, or ink that is invisible or difficult to see in visible light is used. In particular, a phosphor that emits infrared light is used for barcodes and cards (Japanese Patent Laid-Open No. Sho 5).
3-60888), a near-infrared light absorbing dye is used (Japanese Patent Laid-Open No. 64-30788), and two or more kinds of near-infrared dyes having different absorption wavelength regions, or a visible light-absorbing dye ink and near-infrared absorption Color inks may be separately applied or overcoated (Japanese Patent Application Laid-Open No. 58-134782, Japanese Patent Application Laid-Open No. 3-53994,
3-173691) to make a printed portion such as a barcode inconspicuous. However, these methods merely make the bar code and the like of the printing section inconspicuous, and have the drawback that they are easily forged if the detection device and ink are analyzed. Further, at present, with respect to the alteration for closing the punch holes, which is currently a problem with various magnetic cards, the improvement of the detection device is the main measure, and there is no effective measure for the card itself. Further, recently, there have been increasing examples of printing usage records, balance display, etc. on various prepaid cards for the purpose of preventing fraud, but it is not a direct countermeasure against forgery or alteration. An object of the present invention is to solve the above problems and provide a recording material such as a magnetic card which is hard to be forged or altered and a recording method thereof.

[0003]

Means for Solving the Problems As a result of intensive studies for achieving the above object, the present inventors have found that an image receiving layer made of a thermoplastic resin is provided on a base material made of resin or paper, An image, a character, an information recording material on which the layer or the substrate surface is optically differently colored so as to be distinguishable from each other, formation of characters or patterns or images, opacity, or a combination thereof is applied. When recording information such as symbols, it was found that a method for preventing fraud of an information recording material, which optically detects the state of the image receiving layer or the surface of the substrate, is extremely effective for counterfeiting and forgery prevention. Arrived

Hereinafter, the present invention will be described in detail. The present invention provides an image receiving layer having poor solvent resistance so that a modification action performed by processing a card such as closing a punch hole with an adhesive can be easily detected, and there are currently few countermeasures. It is possible to substantially prevent alterations that block punch holes, and also to prevent forgery due to falsification of magnetic recording by recording information corresponding to magnetic recording such as usage records and collating with magnetic recording. Is characterized by.

Recording on the image receiving layer is performed by recording the date and time, the amount of money, etc. by letters and numbers, as well as recording various images such as marks and patterns and signals such as bar codes, and reading these information. By making a comparison with magnetic recording, it becomes possible to detect tampering in the magnetic recording portion. For recording on the image receiving layer, various methods such as electrophotography, ink jet, and thermal transfer can be used. Among these methods, the electrophotographic method such as a laser printer is complicated and difficult to miniaturize, and is more disadvantageous than other methods for printing on a small area such as a card. There is a drawback that it takes time to dry. Therefore, either method can be used in the present invention, but for a card such as a prepaid card, the thermal transfer method is preferable from the viewpoint of simplicity of the apparatus and drying time.

As the base material used in the present invention, a film of polyester such as polyethylene terephthalate, polypropylene, polyimide, polyamide, polyaramid, polyether sulfone, fluororesin or the like, paper or the like is used. As the base material, solvents such as adhesives used for alteration and falsification, aromatic hydrocarbons such as toluene which is a solvent used for wiping, ketones and ethers such as acetone and methyl ethyl ketone, and aliphatic carbonization such as hexane It is preferable to have solvent resistance such that it does not dissolve, swell, or deform even when contacted with an organic solvent such as hydrogen or an ester such as ethyl acetate. To improve the solvent resistance, a thermosetting resin or UV curing is applied to the surface. You may use it, forming the hardened layer processed with the resin.

The image-receiving layer laminated on the surface of the base material is provided to improve the fixability of toner, ink, dye or the like when recording information. In the case of melt heat transfer recording or sublimation heat transfer recording, it plays the role of forming an image by holding the dye or ink containing the dye or the ink containing the dye transferred by the thermal head or the layer receiving the ink layer. It is a layer. The image-receiving layer is inferior in solvent resistance to the above base material, swells with the above organic solvent, or dissolves,
A layer that uses a thermoplastic resin that deforms and has good adhesion to the substrate and a function of stably holding the transferred dye or ink. An intermediate layer may be provided between the substrate and the image receiving layer for the purpose of improving the adhesiveness and coloring the surface of the substrate. Further, the image receiving layer may be laminated on the entire surface of the base material, but may be formed on a part of the surface of the base material such as a portion for recording information. As the thermoplastic resin used for the image receiving layer, a known resin corresponding to the printer to be used can be used, but as the resin for the thermal transfer image receiving layer, a polyester resin, a polyacrylic resin, a polymethacrylic resin,
Examples thereof include polycarbonate resin, polystyrene resin, polyvinyl chloride resin, polyarylate resin, polyvinyl acetal resin, polyvinyl phenyl acetal resin, vinyl chloride / vinyl acetate copolymer resin, and cellulose acetate resin.

These resins can be used alone or as a mixture. In addition to the above, the image receiving layer may include inorganic fine particles such as titanium oxide, calcium carbonate, alumina, silica, fluororesin, silicone resin, thermosetting resin, etc. for the purpose of increasing whiteness and improving the peelability of the color sheet. Fine particles of the organic resin and the like are added if necessary. Further, a plasticizer, an antioxidant, an ultraviolet absorber, a stabilizer, an antistatic agent, a leveling agent and the like can be added.

The intermediate layer which can be provided between the base material and the image receiving layer can also serve as a coloring layer on the surface of the base material in addition to improving the adhesiveness of the image receiving layer. As the resin used for the intermediate layer, in addition to the above resins used for the image receiving layer, a thermosetting resin or an ultraviolet curing resin such as an epoxy resin, a polyurethane resin, or a polyacrylic resin is used. It is possible to add inorganic fine particles and various additives for increasing the temperature.

The image-receiving layer and the intermediate layer of the present invention can be formed by a commonly used coating method (for details, refer to Yuji Harazaki "Coating Method", published by Kakushoten 1977). As a coating machine (coater), a reverse roll coater, a gravure coater, a rod coater, an air doctor coater, a die coater or the like is used, but coating using a gravure coater or a die coater is preferable.

As a solvent for preparing a coating liquid for coating, various organic solvents and water which dissolve and disperse the above-mentioned resins and additives are used. Examples of the organic solvent, methanol, ethanol, propanol, alcohol solvents such as butanol, acetone, methyl ethyl ketone, methyl isobutyl ketone, ketone solvents such as cyclohexanone, ethyl acetate, ester solvents such as butyl acetate, toluene, xylene, Examples thereof include aromatic solvents such as anisole, ether solvents such as tetrahydrofuran and dimethoxyethane, and amide solvents such as N, N′-dimethylformamide and N-methylpyrrolidone.

As the method of forming the image receiving layer, in addition to the above coating method, it is also possible to form the image receiving layer film by laminating or transfer by a heat roll or a thermal head as in the case of laminating a protective layer described later. Since the image-receiving layer thus formed is not subjected to a crosslinking reaction or a curing treatment, it can be easily removed by treating it with various organic solvents such as the above-mentioned solvents and chlorine-based solvents.

The thickness of the substrate used in the present invention is usually 50.
Those having a range from 1 to 500 μm are often used. The thickness of the image receiving layer is 0.1 to 30 μm, preferably 1 to 20 μm, and the thickness of the intermediate layer is 0.1 to 10 μm, preferably 0.5 to 10 μm. The image receiving layer is colored with a dye,
It is possible to add a filler or pigment such as silica or titanium oxide, or to perform opacity or whitening treatment by foaming treatment or the like. Further, it is also possible to form characters, symbols, patterns or images on the entire image receiving layer or on the surface.
The formation of these images and the like is performed by various types of printing or printing by a printer. As the printer, an ink jet printer, a laser printer or the like can be used in addition to the thermal transfer printer. When printing or image formation on the image receiving layer is performed by a printer, it can also be performed at the time of information recording. By performing these treatments on the image receiving layer, for example,
It can be easily recognized when the image receiving layer is removed or deformed by mechanically rubbing the image receiving layer or rubbing with a solvent in order to make alterations to fill the punch holes or falsify the recording on the image receiving layer. Further, even in the case of optical recognition, it is possible to easily discern even a slight modification due to a change in reflectance and a change in image pattern condition.

These treatments can also be performed on the surface of the substrate. Treatment of the surface of the base material is performed on the surface of the base material before forming the image receiving layer or on the surface hardened layer formed to improve solvent resistance, etc., and in some cases, on the intermediate layer for improving the adhesiveness of the image receiving layer. You can also In this case, it is necessary to perform a treatment that is optically different from that of the image-receiving layer, and if the image-receiving layer is peeled off by this treatment, it is possible to more easily distinguish it. The surface treatment of the substrate in the present invention does not necessarily mean the treatment of the outermost surface of the substrate, and the treatment such as coloring and image treatment is performed on the inner layer of the substrate, and a protective layer or a protective layer is formed on top of it. Even if several layers such as a solvent layer are laminated, if they can be optically detected through these layers, they are included in the treatment of the substrate surface.

Various known dyes and pigments are used as dyes used for coloring the surface of the image receiving layer and the substrate and for forming characters and images. In addition to the usual dyes for visible light, near-infrared light is used. Absorption dyes, fluorescent dyes, phosphorescent dyes, photochromic dyes, thermochromic dyes and the like can also be used. Inorganic pigments such as carbon black pigments and inorganic fluorescent pigments can also be used.

Examples of the dye transferred to the image-receiving layer include the above-mentioned inorganic or organic pigments and dyes that can be used for heat transfer by melting, and organic dyes for heat transfer by sublimation. Since commercially available dyes for sublimation thermal transfer generally have low light absorption intensity in the near infrared light region, when the near infrared light absorbing dye is used for the image receiving layer or the substrate surface, the detection of both dyes can be performed separately. It has the advantage of being easy.

Recording of information on the image receiving layer is performed by recording usage of telephone cards and various prepaid cards.
Recording corresponding to recording on the magnetic recording layer, such as date and time, amount of money, and location, is performed by recording signals such as characters, patterns, images, or barcodes. It is possible to detect tampering of the magnetic recording by simultaneously reading and comparing these recordings when reading the magnetic recording. Conventionally, there is an example in which such a record is printed on a prepaid card, but since the record is made directly on the surface of the base material, it is not known if it is wiped off with a solvent and it is easy to falsify the record. On the other hand, tampering with the recorded contents in the image receiving layer as in the present invention is easy because the image receiving layer is easily removed or deformed by wiping with a solvent because the solvent resistance of the image receiving layer is poor. It is extremely difficult to tamper with the change in the state of the image receiving layer. If a part of the image receiving layer is wiped off with a solvent or the like, the pattern signal such as a pattern formed on the image receiving layer is changed or the absorption spectrum of the colored portion is changed, and these abnormalities can be easily detected. Further, it can be easily detected by detecting the surface of the substrate exposed by removing the image receiving layer.
As described above, it is apparent that the formation of the image receiving layer of the present invention makes it extremely difficult to irreversibly tamper with or alter the recording.

When a fluorescent dye, a phosphorescent dye, a photochromic dye, a thermochromic dye or the like is used, detection is performed while irradiating ultraviolet rays or heat rays suitable for the characteristics. In order to more reliably prevent tampering of information recording on the image receiving layer, it is preferable to protect the recording portion with a protective layer after information recording. The protective layer is formed by laminating a transparent film over the recording area and thermocompression bonding, and by laminating the thermal transfer layer provided on one side of the heat-resistant substrate on the recording area and applying a heat roll from the opposite side of the thermal transfer layer. Or a method of transferring the thermal transfer layer onto the recording portion by heating with a thermal head (Japanese Patent Publication No. 4-15).
Although 118) is performed, the latter is preferable as a method of forming the protective layer in a small area of the information recording portion. The resin used for the protective layer is preferably a resin that has good adhesiveness to the image receiving layer, has high mechanical strength, and has better solvent resistance than the image receiving layer, but the same resin as the image receiving layer can also be used. These resins include polyester resins, vinyl chloride-vinyl acetate copolymer resins, polyacrylic resins, epoxy resins,
Examples thereof include polystyrene resin. The protective layer is preferably transparent, but it may be colored to the extent that it does not hinder the detection of recorded information.

As the heat resistant base material for the thermal transfer layer used for forming the protective layer, the base material used as the base material of the thermal transfer recording sheet is used. For example, polyethylene terephthalate, polyamide, polyaramid, polyimide,
Examples thereof include polycarbonate, polyphenylene sulfide, polysulfone and the like. Further, in order to improve the transferability of the thermal transfer layer, it is desirable to provide a release layer between the heat resistant substrate and the thermal transfer layer. As the resin used for the release layer, for example, polyvinyl acetal resin, cellulosic resin,
Examples thereof include polyacrylic resin.

The thermal transfer layer and the peeling layer can be formed in the same manner as the image receiving layer, and the film thickness thereof may be about 1 to 20 μm for the thermal transfer layer and about 0.1 to 5 μm for the peeling layer. If the image receiving layer is formed instead of the thermal transfer layer, the image receiving layer can be formed on the surface of the substrate by the same method as that for laminating the protective layer. In this case, in addition to forming the image receiving layer on the surface of the substrate in advance by the thermal transfer method, the image receiving layer can be formed at the time of recording information. In this case, first, the image receiving layer is formed by thermal transfer, and then information is recorded. The thermal transfer method is more advantageous than the coating method for forming an image receiving layer on a part of a card. The protective layer may be formed over the entire image receiving layer, but it is preferable to keep the image receiving layer portion around the information recording area and leave the image receiving layer portion where the protective layer is not formed for the reason described above for preventing alteration. The resin of the protective layer is a thermoplastic resin and is removed by solvent treatment, but since it has more solvent resistance than the image receiving layer, it requires considerable mechanical force and strong solvent treatment to remove the protective layer. As a result, the surface of the substrate including the image receiving layer is considerably disturbed, and the state can be easily optically detected, and the effect of preventing alteration is great.

[0021]

EXAMPLES The present invention will be described in more detail with reference to examples below, but the examples are not intended to limit the present invention. In addition, "part" in an Example represents a "weight part."

Example 1 A coating solution having the following composition was applied to a synthetic paper base material having a white surface and a thickness of 150 μm (Yupo FPG # 1 manufactured by Oji Yuka Synthetic Paper Co., Ltd.).
50) and dried to form an image receiving layer having a thickness of 5 μm. Coating solution A: Vinyl chloride-vinyl acetate copolymer resin (UCAR-VYHD manufactured by Union Carbide) 10 parts β-type copper phthalocyanine (Ket Blue111 manufactured by Dainippon Ink and Chemicals) 0.1 part Methyl ethyl ketone 15 parts Toluene 15 parts Silicone oil (Shin-Etsu) 0.5 part of KF393 manufactured by Kagaku Kogyo Co., Ltd. The image receiving layer became a sky blue color, which was clearly distinguished from a white base material.
On this substrate, melt thermal transfer printer (PC manufactured by NEC)
-PR101 / T165R), black was printed, and then wiped with gauze impregnated with toluene to remove the print. The image receiving layer was also removed at the same time, and the removed part became clear due to the difference in color. .

Example 2 The coating solution A of Example 1 was applied on a polyethylene terephthalate (PET) film having a thickness of 150 μm and dried to give 5 μm.
After obtaining a layer having a thickness of m, a 6 μm PET film was laminated to obtain a sky blue base material. The following coating liquid B was applied onto this substrate and dried to obtain a white image-receiving layer having a film thickness of 5 μm. Coating liquid B: Aqueous liquid of polyester resin (Polyester WR-900 manufactured by Nippon Gosei Co., Ltd., resin content 20% by weight) 100 parts Silicone oil (KF393 manufactured by Shin-Etsu Chemical Co., Ltd.) 1.5 parts Titanium oxide (manufactured by Ishihara Sangyo Co., Ltd.) Typake CR-60) 10 parts After printing on this image-receiving layer in the same manner as in Example 1 and wiping with toluene, the image-receiving layer was also removed. A certain sky blue appeared and was clearly identifiable. In this way, it was shown that the card can be easily detected if it is treated with a solvent for falsification and alteration.

Comparative Example 1 An image receiving layer was formed in the same manner as in Example 1 except that the coating liquid A of Example 1 was changed to the coating liquid B of Example 2 and the image receiving layer coating liquid C having the following composition. Coating liquid C: Example 1 except that β-type copper phthalocyanine was removed
The image receiving layer formed of the coating liquid B having the same composition as that of the coating liquid B was white, and the image receiving layer formed of the coating liquid C was transparent, and it was difficult to distinguish the image receiving layer from the substrate. When printing was performed on each image-receiving layer in the same manner as in Example 1 and wiped off with toluene, the image-receiving layer was removed together with the ink in the printed portion, but the difference in appearance from the base material was small and removal of the image-receiving layer was removed. It was difficult to determine the situation.

Example 3 Instead of the β-type copper phthalocyanine of the coating solution A of Example 1, a fluorescent whitening agent (Uvitex O manufactured by Ciba-Geigy) was used.
An image receiving layer was formed and printed in the same manner as in Example 1 except that 0.1 part of B) was used. It was difficult to distinguish between the substrate and the image-receiving layer, but when irradiated with ultraviolet light, bluish white fluorescence was observed, which was easily distinguishable from the substrate. When toluene was wiped off and irradiated with ultraviolet light in the same manner as in Example 1, the part where the image receiving layer was removed could be clearly detected.

Example 4 A release layer coating solution having the following composition was prepared. Release layer coating liquid: Polyvinyl acetal resin (Sekisui Chemical Co., Ltd. S-REC KX-1 2 parts Isopropanol 40 parts Water 60 parts This coating liquid is heat-resistant active coated on the back surface and easily adhered to the surface to a film thickness of 6 μm Was coated and dried by a gravure printing machine on the PET film of 1 to form a release layer having a thickness of about 1 μm.
Next, a protective layer coating solution having the following composition was prepared. Protective layer coating solution: Polyester resin (Vylon # 200 manufactured by Toyobo Co., Ltd.) 20 parts Methyl ethyl ketone 80 parts This coating solution was similarly coated and dried on the above-mentioned release layer to prepare a protective layer having a film thickness of 5 μm.

A film of the above-mentioned protective layer was overlaid on the recording portion printed in Example 1, and a printing device (TH manufactured by Okura Electric Co., Ltd. was used.
-PMD), the protective layer was transferred onto the surface of the substrate including the printed portion, and the protective layer was laminated. Next, gauze containing solvent is used for 20
A rubbing and wiping test was performed. With toluene, the image-receiving layer in the portion without the protective layer was removed, and the protective layer was also partially removed to disturb the printing. The protective layer was also wiped off with acetone. In the case of ethanol, there was no change after wiping. As described above, since the image-receiving layer and the protective layer of the present invention are strong against alcohol (ethanol), there is no fear of damaging the image-receiving layer due to adhesion of alcoholic beverages, which is a concern in normal use. It was also shown that the manufacturing was improved, and that it was possible to detect alteration acts by removing or destroying the image receiving layer or the protective layer.

Example 5 A coating solution D having the following composition was prepared. Coating solution D: Vinyl chloride-vinyl acetate copolymer resin (UCAR-VYHD manufactured by Union Carbide Co., Ltd.) 20 parts Amino-modified silicone (KF-393 manufactured by Shin-Etsu Chemical Co., Ltd.) 1 part Toluene 60 parts The layer was coated and dried in the same manner as in Example 4 to obtain an image receiving layer film having a film thickness of 10 μm. Using this film, the image receiving layer was transferred onto the synthetic paper used in Example 1 by the printing apparatus used in Example 4. A color video printer (NV-MP-7 manufactured by Matsushita Electric Industrial Co., Ltd.) was used to form a color pattern on the image-receiving paper, and then information such as date was printed in black. Example 4 is printed on this print section.
A protective layer was laminated in the same manner as in. When a toluene wiping test was performed on this image-receiving paper, the image-receiving layer portion without the protective layer was easily wiped off, but the removed portion was easily discriminated by the disappearance of the color pattern.

Example 6 After the image receiving layer was transferred to the back surface of a prepaid card having a magnetic recording layer in the same manner as in Example 5 using the printing apparatus of Example 4, the card balance was transferred in the same manner as in Example 4. Was printed and the protective layer was transferred. When the magnet was touched, the magnetic record was destroyed and the balance was not displayed on the reader, but the balance of the card could be confirmed by the printed record. When an adhesive was applied to block the punched holes and the surface of the card was rubbed, a part of the image-receiving layer was also wiped off, and the surface of the card substrate was exposed to reveal the alteration.

[0030]

INDUSTRIAL APPLICABILITY According to the present invention, punching is performed by recording information on an image-receiving layer having a solvent resistance lower than that of a substrate, laminating and protecting a protective layer, and detecting the recorded contents and the state of the image-receiving layer at the time of use. In the case of alterations such as filling holes with adhesives, the image receiving layer part is easily affected by the solvent, and the change can be easily detected, and the printed part is protected by the protective layer, and it cannot be rewritten unless the protective layer is destroyed. Even if the magnetic recording is falsified, it can be easily discriminated by collating it with the recording on the image receiving layer, and it is extremely effective for preventing falsification, forgery and alteration of a card or the like, which has been difficult in the past. Further, according to the present invention, the use record of a prepaid card or the like can be visibly recorded, so that it is much clearer than the display using the punch holes, and the convenience for the user is greatly improved.

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Hideo Shinohara, Inventor Hideo Shinohara, 1000 Kamoshida-cho, Aoba-ku, Yokohama, Kanagawa Mitsubishi Chemical Corporation Yokohama Research Institute (72) Takao Hirota 1000, Kamoshida-cho, Aoba-ku, Yokohama, Kanagawa Mitsubishi Chemical Co., Ltd. Yokohama Research Institute

Claims (6)

[Claims] 1. An image receiving layer made of a thermoplastic resin is provided on a base material made of resin or paper, and the image receiving layer or the surface of the base material has optically different colors, letters, patterns or images that can be distinguished from each other. When recording information such as images, characters, symbols, etc. on an information recording material that has been subjected to either formation of opaque material, opacity, or a combination thereof, the state of the image receiving layer or substrate surface is optically A method for detecting fraud in an information recording material, characterized by detecting. 2. The fraud prevention and detection method according to claim 1, wherein the information recording material is recorded by a thermal transfer method. 3. The fraud prevention / detection method according to claim 1, wherein an information recording material having a transparent protective layer for recognizing recorded information after recording the information is used. 4. The fraud prevention and detection method according to claim 3, wherein a part of the image receiving layer other than the information recorded portion is removed and a protective layer is laminated. 5. One or more dyes selected from visible light absorbing dyes, near infrared light absorbing dyes, fluorescent dyes, phosphorescent dyes, photochromic dyes and thermochromic dyes on the image receiving layer and / or the substrate surface. A fraud prevention detection method characterized by forming a character, a pattern, or an image with ink containing ink. 6. The base material contains a magnetic recording layer, and information corresponding to a part of the information recorded on the magnetic recording layer is recorded on the image receiving layer formed on the base material. The fraud prevention detection method according to 1.