JP2021115766A - Magnetism discrimination medium, and genuine-false discrimination method - Google Patents

Abstract

To provide a magnetism discrimination medium that forms a boundary part where magnetic regions on the front and back faces of a substrate contact each other via the substrate and has ability of genuine-false discrimination by a magnetic wave shape detected on the front and back faces of the substrate, in valuable printed matters requiring forgery prevention and manipulation prevention such as a bank note, a passport, securities, an identification card, cards, and a traffic pass, and to provide a genuine-false discrimination method.SOLUTION: A magnetism discrimination medium has a first magnetic region formed by an ink containing a first magnetic material on the front face of a substrate and a second magnetic region formed by an ink containing a second magnetic material on the back face of the substrate. At least a part of the first magnetic region and the second magnetic region forms an adjoining, overlapping, or approaching boundary part on the front and back faces of the substrate. A magnetic wave shape of the boundary part observed by an MR sensor is reversed on the front face and the back face.SELECTED DRAWING: Figure 2

Description

The present invention is true in valuable printed matter such as banknotes, passports, securities, identification cards, cards, toll tickets, etc., which are required to be anti-counterfeiting and anti-tampering, based on the magnetic waveforms detected on the front and back of the base material. The present invention relates to a magnetic discrimination medium capable of false discrimination and a true / false discrimination method.

Valuable printed materials such as banknotes, passports, securities, identification cards, cards, and toll tickets are indispensable to social life, and are financially based on advanced anti-counterfeiting technology and authenticity discrimination technology. Stable maintenance of value and social value is always required.

Conventionally, as the anti-counterfeiting technology for valuable printed matter, confirmation by visual inspection or touch has been the mainstream, but in recent years, machine reading technology utilizing optical characteristics and magnetic characteristics has been introduced in vending machines, POS cash registers, ticket vending machines or ATMs. Widely used.

In particular, the magnetic characteristics are a differential type sensor, a magnetic resistance sensor that simply detects changes in magnetism (hereinafter referred to as "MR sensor"), and magnetism whose impedance changes according to an external magnetic field when a high-frequency current developed in recent years is applied. It is used for authenticity discrimination by comparing magnetic waveforms obtained by various magnetic sensors such as impedance sensors (MI sensors) with reference data.

As an example of how to utilize the magnetic characteristics, a printed image line containing optics and magnetism is formed so that at least a part of the front and back surfaces of the base material overlaps, and the overlapping portion of the front and back surfaces included in the printed image lines formed on the front and back surfaces. By detecting the total value of the optical and magnetic data of the above, a true / false discriminant printed matter that can be machine-readable even with a low-thickness printed image is known (see, for example, Patent Document 1).

Japanese Patent No. 5971714

However, in Patent Document 1, since the detected magnetic waveform is the same on the front and back sides, if the magnetic pattern to be detected can be known, a material containing magnetism is laminated on one side of the base material, which is similar to the genuine one. Even if it is a counterfeit product that reproduces the magnetic waveform, there is a possibility that it will be mistakenly identified as a genuine product.

The present invention solves the above-mentioned problems, and provides a magnetic discrimination medium and a truth discrimination method which have counterfeit resistance and can discriminate authenticity by a magnetic discrimination method having a simple configuration. ..

In order to solve the above-mentioned problems, the present invention presents a first magnetic region formed on the surface of the base material by an ink containing the first magnetic material, and a second magnetic material on the back surface of the base material. A magnetic discrimination medium having a second magnetic region formed by an ink containing the above, wherein at least a part of the first magnetic region and the second magnetic region is adjacent, overlapping, or close to each other on the front and back of the base material. This is a magnetic discrimination medium in which a boundary portion is formed and the magnetic waveform of the boundary portion measured by the MR sensor is inverted on the front surface and the back surface of the base material.

Further, the present invention is a method for determining the authenticity of a magnetic discrimination medium, which comprises a step of measuring the magnetic waveform on the front surface of the base material with an MR sensor and a step of measuring the magnetic waveform on the back surface of the base material with an MR sensor. The magnetic discrimination medium is discriminated as "genuine" when the magnetic waveform at the boundary measured by the MR sensor is inverted between the front surface and the back surface of the base material, including the step of comparing the magnetic waveforms measured on the front surface and the back surface. This is a method for discriminating the authenticity of a magnetic discriminating medium.

In the magnetic discrimination medium of the present invention, when the magnetic waveform of the boundary portion detected by the MR sensor is inverted between the front surface and the back surface of the base material, it can be discriminated as "genuine". A counterfeit product in which a material containing magnetism is laminated can be reliably identified by checking the presence or absence of inversion of the magnetic waveform.

Further, in the magnetic discrimination medium of the present invention, the magnetic waveform is inverted when the first magnetic region and the second magnetic region at the boundary are adjacent, overlapped or close to each other, but the first magnetic region and the second magnetic region are the same. If the adjacency, overlap, or proximity of the magnetic regions is slightly different, the magnetic waveforms on the front and back surfaces of the substrate will not be inverted. Therefore, even if the magnetic pattern to be detected is known, it is difficult to forge it.

In addition, the authenticity determination method of the present invention can perform highly accurate authenticity determination using an MR sensor having a simple configuration.

An example of the magnetic discrimination medium in the first embodiment is shown. The effect of the magnetic discrimination medium in the first embodiment is shown. An example of the magnetic discrimination medium in the second embodiment is shown. The effect of the magnetic discrimination medium in the second embodiment is shown. An example of the flow chart of the method of discriminating the magnetic discriminant medium of the present invention is shown.

A mode for carrying out the present invention will be described with reference to the drawings. However, the present invention is not limited to the embodiments described below, and includes various other embodiments within the scope of the claims.

(First Embodiment)
The first embodiment of the present invention will be described with reference to FIGS. 1 and 2.

FIG. 1 is an example of a magnetic discrimination medium (A1) according to the first embodiment of the present invention, FIG. 1A is a plan view, and FIG. 1B is a cross-sectional view taken along the line AA'.

As shown in FIGS. 1A and 1B, the magnetic discrimination medium (A1) of the present invention contains the first magnetic material in at least a part of the surface (U1) of the base material (1). The first magnetic region (2a) is formed, and the second magnetic region (2b) containing the second magnetic material is formed on at least a part of the back surface (U2) of the base material (1). ing. At this time, a part of the first magnetic region (2a) and the second magnetic region (2b) is in contact with the predetermined direction (S1) on a plane via the base material (1). It has T1).

Here, the "boundary portion (T1)" in the present specification is one of the respective magnetic regions to the extent that the magnetism of the first magnetic region (2a) and the second magnetic region (2b) can be detected at the same time. The part indicates a region in contact with the base material (1), and "contact" in the present specification means that the magnetism of the first magnetic region (2a) and the second magnetic region (2b) can be detected at the same time. Indicates a state of adjacency, overlap, or proximity to some extent. Further, "adjacent" in the present specification means a state in which the first magnetic region (2a) and the second magnetic region (2b) are in contact with the hair removal, and "overlapping" in the present specification means. The distance between the first magnetic region (2a) and the second magnetic region (2b) is smaller than the resolution of the MR sensor (S) described later (for example, if the MR sensor (S) has a resolution of 1 mm, it is about 0 to 1 mm). In the present specification, "proximity" means a distance (for example, a resolution) in which the first magnetic region (2a) and the second magnetic region (2b) are smaller than the resolution of the MR sensor (S). If it is a 1 mm MR sensor (S), the state of being separated by (about 0 to 1 mm) is shown.

In FIG. 1, the first magnetic region (2a) is shown by a vertical line pattern, the second magnetic region (2b) is shown by a diagonal line pattern, and the outline of the first magnetic region (2a) is shown by a solid line and the second. Although the outline of the magnetic region (2b) of the above is shown by a broken line, it does not limit the present invention and is known to print including a mesh pattern or a solid pattern as long as it does not affect the “magnetic waveform” described later. It can be formed with a pattern. Further, for the purpose of concealing the boundary portion (T1), the first magnetic region (2a) or the second magnetic region (2b) is formed on the front surface (U1) and / or the back surface (U2) of the base material (1). It may further have a camouflage region that is uniform in color and does not affect the magnetic waveform.

The printing method for forming the first magnetic region (2a) and the second magnetic region (2b) is not particularly limited as long as the ink can be applied to the base material (1). The magnetic region (2a) is a first magnetic material, and the second magnetic region (2b) is a second magnetic material mixed with a vehicle and an additive, respectively, in concave printing, screen printing, flexo printing, and inkjet. It can be carried out by a known printing method such as printing.

As the first magnetic material and the second magnetic material, a soft magnetic material and / or a semi-hard magnetic material can be used. As an example of the soft magnetic material, general magnetic materials such as iron-silicon, iron-nickel, Mn-Zn ferrite, permalloy, and amorphous magnetic material can be used. As an example of the semi-hard magnetic material, a general magnetic material such as Ba ferrite, Sr ferrite, alnico, and neodymium magnet can be used. In FIG. 1, the same material is magnetized for the first magnetic material and the second magnetic material at the same content, but the present invention is not limited and the magnetic waveform is not affected. Materials having different known magnetic properties including saturation magnetization, residual magnetization, magnetic permeability and coercive force may be used, or the same material may have different contents. These can be arbitrarily selected as long as the effects of the present invention can be obtained.

The vehicle that can be used in the present invention is not particularly limited as long as it does not affect the magnetic waveform. Natural waxes such as Uva wax, paraffin wax, ester wax, synthetic waxes such as low molecular weight polyethylene, higher fatty acids such as lauric acid, myristic acid, palmitic acid, and stearic acid, and higher grades such as stearyl alcohol and heberyl alcohol. Alcohols, soaps such as vaseline and glycerin, hydrocarbons such as glucose, ethylene glucose and amylose, esters such as fatty acid esters, amides such as steaamide and oleinamide, polyamide resins, polyester resins and epoxys. Resin, polyurethane resin, acrylic resin, vinyl chloride resin, cellulose resin, polyvinyl resin, petroleum resin, ethylene-vinyl acetate copolymer resin, phenol resin, styrene resin, rosin modified resin, terbin resin Resins such as natural rubber, styrene butadiene rubber, isopropylene rubber, elastramers such as chloroprene rubber, waxed petroleum resin, silicone, liquid paraffin, tack fires such as fluororesin, etc. A dispersion medium consisting of can be used.

As the additive that can be used in the present invention, pigments, dyes, surfactants, fillers, antioxidants, desiccants and the like can be used as long as they do not affect the magnetic waveform. In addition to colored pigments, pigments include known extender pigments such as calcium carbonate, alumina, barium sulfate, zinc oxide, and titanium oxide, as well as fluorescent pigments, pearl pigments, glass flakes, cholesteric liquid crystal pigments, and phosphorescent pigments. Known functional pigments can be used.

The base material (1) that can be used in the present invention is not particularly limited as long as it is a material that does not affect the magnetic waveform, and known materials including paper, plastic, metal, and the like can be used.

Next, the effect of the first embodiment of the present invention will be described with reference to FIG.

FIG. 2 is a diagram showing a magnetic waveform obtained by transporting an MR sensor (S) facing the magnetic discrimination medium (A1) in a predetermined direction, and FIG. 2A is a diagram showing a first magnetic region (a). The first magnetic waveform (P) obtained by transporting the surface (U1) on which 2a) is arranged in a predetermined direction (S1'), FIG. 2 (b) shows the magnetic discrimination medium (A1) of FIG. 2 (a). With the second magnetic waveform (P'), the back surface (U2) in which the second magnetic region (2b) is arranged is conveyed in a predetermined direction (S1 ″) by inverting the front and back around AA'. be.

The MR sensor (S) utilizes the magnetic resistance effect in which the electrical resistance of a solid changes with a magnetic field, and the appearance of a magnetic material is a positive voltage change, based on the midpoint voltage in the absence of magnetism. It is a magnetic sensor that detects the disappearance of each as a change in negative voltage, and the magnetic detection sensitivity becomes stronger as the distance between the MR sensor (S) and the magnetic material increases, and the distance from the magnetic material increases. Therefore, it has the characteristic of decreasing. That is, the magnetic detection sensitivity of the MR sensor (S) depends on the distance from the magnetic material.

In FIG. 2A, the first magnetic waveform (P) has a first peak (P1) and a first magnetic region (2a) at the boundary between the base material (1) and the first magnetic region (2a). The second peak (P2) at the boundary (T1) between the second magnetic region (2b) and the second magnetic region (2b), and the third peak (P3) at the boundary between the second magnetic region (2b) and the base material (1). Is observed. At this time, at the boundary portion (T1) of the surface (U1), a negative voltage due to the disappearance of the first magnetic region (2a) and a positive voltage due to the appearance of the second magnetic region (2b) are simultaneously generated. However, since the first magnetic region (2a) is close to the MR sensor (S), the detection sensitivity is high, and the second magnetic region (2b) is based on the distance from the MR sensor (S). The second peak (P2) is observed as a relatively negative voltage because it is separated from the first magnetic region (2a) by the thickness of (1) and the detection sensitivity is reduced.

On the other hand, in FIG. 2B, the second magnetic waveform (P') is the first peak (P1') at the boundary between the base material (1) and the first magnetic region (2a), the first. The second peak (P2') at the boundary (T1) between the magnetic region (2a) and the second magnetic region (2b), and the second peak (P2') at the boundary between the second magnetic region (2b) and the base material (1). A peak of 3'(P3') is observed. At this time, at the boundary portion (T1) of the back surface (U2), a negative voltage due to the disappearance of the first magnetic region (2a) and a positive voltage due to the appearance of the second magnetic region (2b) are simultaneously generated. However, since the distance between the first magnetic region (2a) and the MR sensor (S) is larger than that of the second magnetic region (2b) due to the thickness of the base material (1), the detection sensitivity becomes smaller and the second magnetic region (2a) becomes smaller. Since the magnetic region (2b) of the above is close to the MR sensor (S) and the detection sensitivity is large, the second peak (P2') can be observed as a relatively positive voltage.

That is, the second peak (P2) and the second peak (P2') at the positions corresponding to the boundary portion (T1) can be observed inverted on the front and back sides of the magnetic discrimination medium (A1). Here, "reversal" in the present specification means a state in which the change in voltage with respect to the midpoint voltage is reversed between "positive" and "negative".

Therefore, if the peaks of the magnetic waveform are inverted on the front and back of the boundary portion (T1) between the front surface (U1) and the back surface (U2), it can be determined that the magnetic discrimination medium (A1) is “genuine”.

In FIG. 2, the MR sensor (S) is conveyed with the magnetic discrimination medium (A1) fixed, but if the magnetic discrimination medium (A1) and the MR sensor (S) are relatively moving, MR is carried. A similar magnetic waveform can be obtained even if the sensor (S) is fixed and the magnetic discrimination medium (A1) is conveyed. Further, the transport directions (S1', S1'') of the MR sensor (S) are reversed if the start point and end point of the transport are common on the front and back sides of the magnetic discrimination medium (A1) centered on AA'. A similar magnetic waveform can be obtained in any direction.

Further, in FIG. 2, the MR sensor (S) is individually conveyed to the front surface (U1) and the back surface (U2), but the MR sensor (S) is arranged on both sides of the magnetic discrimination medium (A1). , The first magnetic waveform (P) and the second magnetic waveform (P') can be obtained at the same time by carrying the MR sensor (S) or the magnetic discrimination medium (A1).

Further, in FIG. 2, the first magnetic material and the second magnetic material are the same, and the intensities of the second peak (P2) and the second peak (P2') are almost the same, but the first magnetism. Even when the coercive force of the material and the second magnetic material are different, the intensity of the peaks may be different as long as the peaks at the boundary portion (T1) are reversed on the front and back sides.

Further, in FIG. 2, the first magnetic waveform (P) and the second magnetic waveform (P') are visually compared, and the second peak (P2) and the second peak (P2') are inverted. However, the measurement data of the MR sensor (S) is transmitted to the mechanical processing unit (not shown), and as shown in the flow chart shown in FIG. 5, the surface (U1) of the base material (1) is set in Step 1. The first magnetic waveform (P) of the above is measured, the second magnetic waveform (P') of the back surface (U2) of the base material (1) is measured with Step 2, and the boundary portion (T1) is measured with Step 3. The second peak (P2) and the second peak (P2') at the desired position are compared, and when the peaks are inverted, the magnetic discrimination medium (A1) is subjected to mechanical processing to determine "authenticity". It is also possible.

Further, the base material (1) is composed of a plurality of layers, and one or both of the first magnetic region (2a) and the second magnetic region (2b) on the outermost surface is at least the base material (1). It may further have an nth magnetic region (n> 3) in contact with each other via one intermediate layer.

Further, in the magnetic discrimination medium (A1) in FIGS. 1 and 2, each magnetic region is individually formed on the front and back surfaces of the base material (1), but this does not limit the present invention, and the effect of the present invention is not limited. If it can be formed as shown in the above, at least one layer other than the base material (1) including ink, film, plastic sheet and the like is formed between the first magnetic region (2a) and the second magnetic region (2b). May be formed.

Further, on the upper surface of the first magnetic region (2a) and / or the second magnetic region (2b), a layer including ink, film, plastic sheet, etc. is provided within a range that does not affect the effect of the present invention. The layer may be a concealing layer that visually conceals the first magnetic region (2a) and / or the second magnetic region (2b).

That is, the layer structure of the magnetic discrimination medium (A1) of the present invention can be appropriately adjusted as long as the effects of the present invention are not impaired.

If the first magnetic region (2a) and the second magnetic region (2b) overlap at a distance larger than the resolution of the MR sensor (S), the second peak (P2) and the second peak (P2) and the second peak (P2') shows a positive waveform after a negative waveform and does not show inversion, which is not preferable. Further, when the first magnetic region (2a) and the second magnetic region (2b) are separated by a distance larger than the resolution of the MR sensor (S), the second peak (P2) and the second peak (2') ( P2') shows a negative waveform after a positive waveform and does not show inversion, which is not preferable.

The resolution of the MR sensor (S) differs depending on the manufacturer and the type of product, and also depends on the relative moving speed with the magnetic discrimination medium (A1). Therefore, the content of the magnetic material in the ink and the printing time. The film thickness and the range of adjacency, overlap or proximity at the boundary (T1) can be adjusted as appropriate.

Further, the material and thickness of the base material (1) used in the present invention and the layers other than the above-mentioned base material (1) can be appropriately adjusted so as to show the effect of the present invention.

Further, the region where the boundary portion (T1) is formed is limited to the range where the MR sensor (S) obtains the magnetic waveform of the magnetic discrimination medium (A1), and the other regions are arranged in the first magnetic region (2a). By arranging the second magnetic region (2b) at a distance larger than the resolution of the MR sensor (S) and / or separating them from each other, the magnetic discrimination medium (A1) can perform more accurate authenticity discrimination. It is possible.

(Second embodiment)
A second embodiment of the present invention will be described with reference to FIGS. 3 and 4. FIG. 3 is an example of the magnetic discrimination medium (A2) according to the second embodiment of the present invention, FIG. 3 (a) is a plan view, and FIG. 3 (b) is a cross-sectional view of AA'in the long side direction. , FIG. 3 (c) is a cross-sectional view of BB'in the short side direction.

The magnetic discrimination medium (A2) shown in FIGS. 3 (a) and 3 (b) has a first magnetic region (2a) and a first'magnetic region (2a') on the surface (U1) of the base material (1). ), The second magnetic region (2b) and the second'magnetic region (2b') are formed in a matrix on the back surface (U2) of the base material (1). At this time, as shown in FIG. 3B, the first magnetic region (2a) and the second magnetic region (2b) are first with respect to the long side direction (S1) of the magnetic discrimination medium (A2). As shown in FIG. 3 (c), the first magnetic region (2a') and the second magnetic region (2b) are of the magnetic discrimination medium (A2). It has a second boundary portion (T2) with respect to the short side direction (S2).

In FIG. 3, two magnetic regions (2a, 2a') are formed on the front surface (U1) of the base material (1), and two magnetic regions (2b, 2b') are formed on the back surface (U2). The present invention is not limited, and the number of each magnetic region may be three or more as long as it does not affect the magnetic waveform described later. Further, in FIG. 3, a boundary portion is provided in two directions, a long side direction and a short side direction, but this does not limit the present invention, and is oblique unless it affects the magnetic waveform described later. It may have a boundary portion with respect to three or more directions such as a direction.

Next, the effect of the second embodiment of the present invention will be described with reference to FIG. The principle of the second embodiment of the present invention is the same as that of the first embodiment, and thus the description thereof will be omitted.

FIG. 4 is obtained by transporting the MR sensor (S) facing the magnetic discrimination medium (A2) in the long side direction (S1', S1'') and the short side direction (S2', S2''), respectively. It is a figure which shows the magnetic waveform.

FIG. 4A shows the magnetic waveform (PA) of the first A in which the long side (U1A) of the surface (U1) on which the first magnetic region (2a) is arranged is conveyed in the S1'direction, and FIG. 4 (b). ) Inverts FIG. 4A with AA'as the axis, and conveys the long side (U2A) of the back surface (U2) in which the second magnetic region (2b) is arranged in the S1'' direction. In the second A magnetic waveform (PA') and FIG. 4 (c), the short side (U1B) of the surface (U1) on which the first'magnetic region (2a') is arranged is conveyed in the S2'direction. The magnetic waveform (PB) of the first B and FIG. 4 (d) show the back surface of FIG. 4 (c) in which the second magnetic region (2b) is arranged by inverting the front and back of FIG. 4 (c) with the BB'as the axis. The magnetic waveform (PB') of the second B in which the short side (U2B) of (U2) is conveyed in the S2 ″ direction is shown.

In FIG. 4A, the magnetic waveform (PA) of the first A has a peak (PA1) of the first A and a first magnetic region (2a) at the boundary between the base material (1) and the first magnetic region (2a). ) And the first boundary (T1) of the second magnetic region (2b), the second peak (PA2), and the boundary between the second magnetic region (2b) and the substrate (1) of the third A. A peak (PA3) is observed. At this time, at the first boundary portion (T1) of the long side (U1A) of the surface (U1), the peak (PA2) of the second A is observed as a relatively negative voltage.

On the other hand, in FIG. 4B, the magnetic waveform (P') of the second A is the peak (PA1') of the first A'at the boundary between the base material (1) and the first magnetic region (2a), the first. 2A'peak (PA2') at the first boundary (T1) of the magnetic region (2a) and the second magnetic region (2b), and the second magnetic region (2b) and the base material (1). The peak of the third A'(PA3') is observed at the boundary of). At this time, at the first boundary portion (T1) of the long side (U2A) of the back surface (U2), the peak (PA2') of the second A'can be observed as a relatively positive voltage.

Next, in FIG. 4 (c), the magnetic waveform (P _{B ) of the first B is the peak (P B} 1) of the first B at the boundary between the base material (1) and the second magnetic region (2 b). The second peak (PB2) at the second boundary (T2) between the second magnetic region (2b) and the first'magnetic region (2a'), and the first'magnetic region (2a'). A third B peak (PB3) is observed at the boundary of the material (1). At this time, at the second boundary portion (T2) of the short side (U1B) of the surface (U1), the peak (PB2) of the second B can be observed as a relatively positive voltage.

On the other hand, in FIG. 4D, the magnetic waveform (PB') of the second B is the peak (PB1') of the first B'and the second at the boundary between the base material (1) and the second magnetic region (2b). At the second boundary (T2) between the magnetic region (2b) and the first'magnetic region (2a'), the second B'peak (PB2'), and the first'magnetic region (2a'). A third B'peak (PB3') is observed at the boundary of the substrate (1). At this time, at the second boundary portion (T2) of the short side (U2B) of the back surface (U2), the peak (PB2') of the second B'can be observed as a relatively negative voltage.

At this time, comparing the magnetic waveform (PA) of the first A in FIG. 4 (a) and the magnetic waveform (PA') of the second A in FIG. 4 (b), it corresponds to the first boundary portion (T1). The second A peak (PA2) and the second A'peak (PA2') at the position can be observed inverted on the front and back of the magnetic discrimination medium (A2).

Further, when comparing the magnetic waveform (PB) of the first B in FIG. 4 (c) and the magnetic waveform (PB') of the second B in FIG. 4 (d), the position corresponding to the second boundary portion (T2) is compared. The second B peak (PB2) and the second B'peak (PB2') can be observed inverted on the front and back of the magnetic discrimination medium (A2).

That is, in the magnetic discrimination medium (A2), the peaks of the magnetic waveform can be observed inverted on the front and back of the first boundary portion (T1) in the long side direction and the second boundary portion (T2) in the short side direction. .. Therefore, even if the MR sensor (S) has a plurality of transport directions with respect to the magnetic discrimination medium (A2), if the peaks of the magnetic waveform are inverted on the front and back of the boundary portion for each transport direction, the magnetic discrimination is performed. It can be determined that the medium (A2) is "genuine".

Examples of the present invention will be described with reference to FIGS. 1 and 2. In the examples of the present invention, copy paper (thickness 0.09 mm) was used as the base material (1), and an ink containing 2.5% magnetic ferrite and 2.5% iron black was used as the magnetic material.

Using the same ink containing a magnetic material, a solid pattern of 5 mm square with a film thickness of 5 μm was printed on one side (U1) and the other side (U2) of the base material (1). At this time, printing was performed so that the boundary portion (T1) overlapped by 1 mm.

By printing, a magnetic discrimination medium (A1) in which the first magnetic region (2a) and the second magnetic region (2b) shown in FIG. 1 were formed was obtained.

With respect to the created magnetic discrimination medium (A1), an MR sensor (S) having a resolution of 1 mm is opposed to the surface (U1) on which the first magnetic region (2a) is arranged, and the direction (A) shown in FIG. As a result of transporting to S1'), the first magnetic waveform (P) shown in FIG. 2 (a) was obtained. After that, the magnetic discrimination medium (A1) is turned upside down about AA', and the MR sensor (S) is opposed to the back surface (U2) where the second magnetic region (2b) is arranged. As a result of transporting in the predetermined direction (S1 ″) shown in b), the second magnetic waveform (P') shown in FIG. 2 (b) was obtained.

In FIG. 2A, the first magnetic waveform (P) has a first peak (P1) and a first magnetic region (2a) at the boundary between the base material (1) and the first magnetic region (2a). The second peak (P2) at the boundary (T1) between the second magnetic region (2b) and the second magnetic region (2b), and the third peak (P3) at the boundary between the second magnetic region (2b) and the base material (1). Was observed. At this time, the second peak (P2) at the boundary portion (T1) of the surface (U1) is observed as a negative voltage due to the disappearance of the first magnetic region (2a) facing the MR sensor (S). rice field.

On the other hand, in FIG. 2B, the second magnetic waveform (P') is the first peak (P1') at the boundary between the base material (1) and the first magnetic region (2a), the first. At the boundary (T1) between the magnetic region (2a) and the second magnetic region (2b), the second peak (P2'), and at the boundary between the second magnetic region (2b) and the base material (1). A third peak (P3') was observed. At this time, the second peak (P2') at the boundary portion (T1) of the back surface (U2) becomes a positive voltage with the appearance of the second magnetic region (2b) facing the MR sensor (S). I was able to observe it.

That is, the second peak (P2) and the second peak (P2') at the positions corresponding to the boundary portion (T1) could be observed inverted on the front and back of the magnetic discrimination medium (A1). Therefore, it was found that if the peaks of the magnetic waveform are inverted on the front and back sides of the boundary portion (T1) between the front surface (U1) and the back surface (U2), the magnetic discrimination medium (A1) can be determined to be “genuine”.

A1, A2 Magnetic discrimination medium 1 Base material 2 Magnetic region 2a First magnetic region 2a'First'magnetic region 2b Second magnetic region 2b'Second' magnetic region T1, T2 Boundary U1 Front surface U2 Back surface U1A Long side of front surface U2A Long side of back surface U1B Short side of front surface U2B Short side of back surface P First magnetic waveform P'Second magnetic waveform PA First A magnetic waveform PA'Second A magnetic waveform PB First Magnetic waveform of B PB'Magnetic waveform of second B S1, S1', S1'' Moving direction S MR sensor

Claims (2)

A first magnetic region formed on the surface of the base material by an ink containing a first magnetic material, and a second magnetic region formed on the back surface of the base material by an ink containing a second magnetic material. A magnetic discrimination medium including a region, wherein at least a part of the first magnetic region and the second magnetic region forms adjacent, overlapping, or adjacent boundaries on the front and back surfaces of the base material, and the MR sensor. The magnetic discrimination medium, wherein the magnetic waveform of the boundary portion measured in 1 is inverted on the front surface and the back surface of the base material. The method for determining the authenticity of a magnetic discrimination medium according to claim 1, wherein the magnetic waveform on the front surface of the base material is measured by the MR sensor, and the magnetic waveform on the back surface of the base material is measured by the MR sensor. When the step and the step of comparing the magnetic waveforms measured on the front surface and the back surface are included, and the magnetic waveform of the boundary portion measured by the MR sensor is inverted on the front surface and the back surface of the base material, the above. A method for determining the authenticity of a magnetic discrimination medium that discriminates the magnetic discrimination medium as genuine.

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