JPH08153233A - Method for identifying validity/invalidity of mark with invisible ink - Google Patents

Abstract

PURPOSE: To surely judge the validity/invalidity of a mark by irradiating the mark obtained by superposingly applying a process ink on the surface of a mark printed with an infrared-ray absorbing ink, with infrared rays and visible light. CONSTITUTION: A reading mark 4 such as a bar code is printed on a security 1 and process ink (e.g. red) is superposedly applied on the surface of the mark 4. The mark 4 is irradiated with infrared rays by a 1st light emitting element 5 and its reflected light is received by a light receiving element 7. An arithmetic processor 8 judges the mark 4 as a true one when an absorption rate is maximum at 1000nm e.g. and judges it as a forgery when an infrared-ray area is not absorbed. At the time of judging the mark 4 as a true one, the mark 4 is irradiated with red light by a 2nd light emitting element 6 and its reflected light is received by the element 7. The processor 8 judges the mark 4 as a true one when the red light is reflected at 650nm and judges it as a forgery when the red light is not reflected.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method of authenticating a mark with an invisible ink used for securities and the like.

[0002]

2. Description of the Related Art Recently, for securities such as stock certificates, bonds, checks, and gift certificates, and related products that replace cash vouchers such as ID cards, credit cards, cash cards, etc., machine-readable bar codes, confidential information, etc. Mark is printed or magnetically recorded on the medium.

[0003] By the way, since bar code or secret information printed by black light or magnetically recorded may be tampered with in related products such as securities and cash vouchers.
It is necessary to verify the authenticity of the barcode and confidential information. Conventionally, when checking the authenticity of a barcode or secret information of this kind by using a machine, there are fluorescence, emission of light, and reading of magnetic recording.

[0004]

However, since black light is easily available, it is immediately known where on the medium the fluorescent ink is contained, and since magnetic recording is widely known, it is easy to be forged.

Therefore, recently, along with the development of the infrared absorbing printing ink, there is one in which a bar code or secret information is printed on a medium with this ink. This infrared absorbing printing ink has sufficient absorption characteristics in the infrared region, but does not absorb in the visible region.

Therefore, if a bar code for reading check or secret information is printed on a medium with such infrared absorbing printing ink, it is not known where on the medium these are, so it is effective in preventing forgery and falsification. Is.

However, if only the infrared region is checked by the reader, if the bar code or the secret information is printed with a smear ink containing carbon black, it will absorb any deviation between the visible region and the infrared region. However, there is a problem that even a product printed with Sumi ink is judged to be a genuine product.

According to the present invention, the authenticity of a mark with an invisible ink can be surely judged, such as a bar code for reading check or secret information printed on a medium with infrared absorbing printing ink. The purpose is to provide a method.

[0009]

In order to achieve the above object, the present invention is to identify the authenticity of a mark made by an invisible ink by the following method. According to the first aspect of the present invention, the authenticity of the mark of the medium in which the process ink is read and the mark is overprinted on the reading mark such as the barcode or the secret information printed by the infrared absorbing ink is overwritten. The mark is irradiated with infrared light and visible light, the infrared light is absorbed, and the visible light is reflected.

According to a second aspect of the present invention, the authenticity of the mark of the medium obtained by reading the process ink on the reading mark of the bar code or secret information printed by the infrared absorbing ink and the printed mark is superimposed. When appraising, the mark is first irradiated with infrared light to check the absorption in the infrared region, it is judged whether or not the infrared light has been absorbed, and if the infrared light has been absorbed, the mark is visible in red. Light is irradiated to check absorption in the visible region, and visible light is reflected, so the product is judged to be genuine.

[0011]

In the invention corresponding to claim 1, the mark is irradiated with infrared light and visible light, and when the infrared light is absorbed and visible light is reflected, it is judged to be a genuine product. It is possible to determine whether the product is a counterfeit product or not, and since the authenticity of the mark is determined by the reflection of visible light by checking the visible region, it is possible to distinguish it from the product printed with Sumi ink.

In the invention according to claim 2, since the visible region is checked after the absorption in the infrared region is checked, even if the mark is imitated with visible ink, the infrared region Just by checking the absorption, it is possible to immediately judge the forgery of the mark.

[0013]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below with reference to the drawings. FIG. 2 shows an example of the structure of an object for which the authenticity of a mark is verified by the method of the present invention. That is, as shown in FIG. 2, a mark 1 for reading a bar code, secret information or the like is printed on the securities 1 as a medium with the infrared absorbing ink 2, and the process ink (for example, red) 3 thereon is the same as the read mark. Overprint in size. Therefore, it seems that only the red mark is printed on the appearance.

Here, the infrared absorbing ink is an invisible ink which has a sufficient absorbing property in the infrared region but does not absorb in the visible region, and the process ink absorbs in the visible region. However, it is used as a masking ink that does not absorb in the infrared region. Therefore, it is desirable that the hiding ink has a small difference between the color of the hiding ink and the color of the infrared absorbing ink when the ink is superposed.

FIG. 1 shows an example of the construction of a reading device for marks such as bar codes and secret information printed on securities 1 as described above. In FIG. 1, a first light emitting element 5 that irradiates the mark 4 on the security 1 with infrared light, and a second light emitting element 6 and the mark 4 that similarly irradiate the mark 4 with visible light are shown. Comprised of a light receiving element 7 for detecting the reflected infrared light and reflected light of a wavelength that does not absorb visible light, the visible light to infrared light detected by this light receiving element 7 is converted into an electric signal and arithmetic processing is performed. The data is input to the device 8 and the arithmetic processing necessary for authenticating the mark is executed.

Next, the operation will be described with reference to the flow chart shown in FIG. Now, the process ink used as the visible ink (red) absorbs (the reflectance is small) in the region where the wavelength of red is, for example, 400 nm to 600 nm as shown in FIG. 4, and is reflected (reflection) when the wavelength is larger than this. The infrared absorption ink used as a visible ink has a wavelength in the infrared region of 720n.
It is assumed that a material that gradually exhibits absorption from m and has a maximum absorption at 1000 nm is selected.

Under these conditions, the first light emitting element 5 irradiates the mark 4 with infrared light, and when the reflected light is received by the light receiving element 7, it is converted into an electric signal and the arithmetic processing unit 8 is operated. To enter.

In this arithmetic processing unit 8, the absorption in the infrared region is checked in step S1, and if the absorption coefficient shows the maximum at 1000 nm in step S2, it is judged to be genuine, and the process proceeds to step S3. If it does not show absorption in the infrared region, it is judged as a counterfeit product in step 6 and the fact is output.

Next, when it is determined in step S2 that the bill is genuine, the first light emitting element 5 irradiates the mark 4 with red light, and the reflected light is received by the light receiving element 7.
This is converted into an electric signal and input to the arithmetic processing unit 8.

Then, in the arithmetic processing unit 8, step S3
In step S4, if the absorption in the visible region is checked, for example, if the red wavelength shows 650 nm and reflection is shown, it is judged as a genuine product in step S5, and if it is not reflected, it is judged as a counterfeit product in step S6. Is output.

As described above, in this embodiment, the process ink (for example, red) 3 is read and the mark is overprinted on the mark for reading the bar code or secret information printed by the infrared absorbing ink 2 (this example). In order to verify the authenticity of the mark of securities 1 overprinted with the same size as the read mark), the mark was irradiated with infrared light to check the absorption in the infrared region, and the infrared light was absorbed. It is judged as genuine, and the mark is irradiated with red visible light to check the absorption in the visible region, and since it is judged as genuine by reflecting visible light, for example, the mark is made with red visible ink. Even if you imitate, just by checking the absorption in the infrared region, you can immediately determine that it is a counterfeit product.

In addition, when the bar code or secret information is printed with a smear ink containing carbon black, it has the property of absorbing any deviation between the visible region and the infrared region, so only the infrared region is checked. However, since the authenticity of the mark is determined by the reflection of visible light by checking the visible area in this embodiment, it is possible to distinguish it from the one printed with Sumi Ink and print with Sumi Ink. It is no longer possible to judge the marked mark as a genuine note.

In the above-mentioned embodiment, the absorption check in the visible region is performed after the absorption check in the infrared region. However, it is possible to determine the genuine product and the counterfeit product by reversing the order.

Further, in the above-mentioned embodiment, the first light emitting element irradiates infrared light and the second light emitting element irradiates visible light. However, as shown in FIG. 10A provided with a light emitting element 9 for irradiating light including light and facing the optical path from the light emitting element 9 and transmitting only infrared light
Alternatively, the filter 10B that transmits only visible light may be detachably provided, and the filter 10B may be switched to the filter 10B after use.

[0025]

As described above, according to the present invention, it is possible to reliably determine the authenticity of a mark such as a bar code for reading check or secret information printed on a medium with infrared absorbing printing ink. It is possible to provide a method of authenticating a mark by using an invisible ink.

[Brief description of drawings]

FIG. 1 is a diagram showing a configuration example of a mark reading device for explaining a method of the present invention.

FIG. 2 is a diagram showing a configuration example of an object whose authenticity of a mark is verified by the method of the present invention.

FIG. 3 is a flow chart for explaining an embodiment of the method of the present invention.

FIG. 4 is a characteristic curve diagram showing absorption rates of infrared light and visible light of visible ink and invisible ink.

FIG. 5 is a diagram showing a configuration example of another mark reading device for explaining the method of the present invention.

[Explanation of symbols]

1 ... Securities, 2 ... Infrared absorbing ink, 3 ... Process ink, 4 ... Mark, 5 ... First light emitting element, 6
...... Second light emitting element, 7 ...... Light receiving element, 8 ...... Arithmetic processing device.

Claims (2)

[Claims] 1. A red mark is applied to a mark on a medium in which a process ink is read and a mark is overprinted on a mark for reading a bar code or confidential information printed with infrared absorbing ink. A method of authenticating a mark with an invisible ink, which comprises irradiating external light and visible light, absorbing infrared light, and judging that the visible light is reflected as a genuine product. 2. When the authenticity of the mark of the medium in which the process ink is read and the mark is overprinted on the mark for reading the bar code or confidential information printed with the infrared absorbing ink is first judged as the mark. Irradiate infrared light to check absorption in the infrared region, determine whether infrared light has been absorbed, and then irradiate the mark with red visible light on condition that infrared light has been absorbed. A method of authenticating a mark with an invisible ink, characterized by checking the absorption in the visible region and judging that it is a genuine product by reflecting visible light.