JP2022017637A - Method for discriminating printed matter - Google Patents

Abstract

To solve the problem that there is a need for a special chemical element contained in ink or a need for multiple inks to impart information to a chemical element, in order to discriminate authenticity of printed matters having high security.SOLUTION: A method for discriminating printed matters includes: an information imparting part which expresses information formed according to differentiation in irradiation timings of light with a prescribed wavelength, by using ink that cures by being irradiated with light of the prescribed wavelength, on a part of a permeable substrate; and a concealing part disposed around the information imparting part. In the method for discriminating printed matters, the same light as the light of the prescribed wavelength or light having a different wavelength is scanned while focusing on the information imparting part and/or the concealing part, and reflectance is obtained for conversion to image information of a plane surface. Then, a plurality of the image information of the plane surface are superposed to form one piece of synthetic image information, in order to read the information imparting part according to a difference in surface shape between the information imparting part and the concealing part.SELECTED DRAWING: Figure 1

Description

The present invention is the final in forgery and falsification of banknotes, which are security printed matter requiring authenticity, passports as products including securities and personal identification elements, identification cards, cards, toll tickets, and various certificates. It is related to the authenticity discrimination method.

Various counterfeiting and alteration prevention technologies are applied to products containing security printed matter and personal identification elements. Squid technology for the general public to easily determine the presence or absence of forgery or alteration, color change ink, fluorescent ink, magnetic ink for determining the presence or absence of forgery or alteration with an optical change device (OVD) or machine, Forgery prevention technology such as infrared transmission absorption ink is introduced into one or more printed products to confront counterfeiting or alteration.

However, as for the elements as anti-counterfeiting / alteration technology, counterfeiting / alteration is repeated by all means, such as manufacturing by obtaining the exact same material or adding similar elements by another material or method. It has been. Even if new forgery / alteration prevention technology that is difficult to counterfeit / alter is developed due to technological progress, new counterfeit / alteration products will appear for that technology. In other words, counterfeiting / anti-counterfeiting technology and counterfeiting / alteration technology have always been in a shield-and-spear relationship, and no matter how good anti-counterfeiting technology is applied, counterfeiting and alteration products will occur.

Therefore, a authenticity discrimination method for detecting a fake or a fake product is required. For example, by printing specific information with an ink containing a special element and then concealing the portion with another ink, the specific information cannot be identified with the naked eye. However, a technique for reading specific information by performing mapping analysis of a special element on this printed matter using a fluorescent X-ray analyzer has been proposed (see, for example, Patent Document 1).

Further, after printing on paper in the form of personal information using ink in which predetermined information is given to each of a plurality of elements in advance, a pattern is printed in which the portion is covered with another ink. Then, as in Patent Document 1, a technique has been proposed in which a plurality of elements are mapped and analyzed for each element using a fluorescent X-ray analyzer, and the information is read as personal information based on the information given in advance. (See, for example, Patent Document 2).

Japanese Unexamined Patent Publication No. 2000-218920 Japanese Unexamined Patent Publication No. 2000-25155

However, since the method for discriminating printed matter of Patent Document 1 and Patent Document 2 requires adding a special element to the ink, printing is first performed with the ink containing this special element, and then printing is performed. It was limited to special uses because it had to be printed for concealment. The reason is that there is a risk that the position and contents of the given confidential information may be leaked until the printed matter to which the information is given by the ink containing a special element is concealed by the printing in the next process.

Further, since the image is constructed by the mapping method by moving the sample stage, a region of 5 mm × 5 mm or more is required to add information as the resolution of the image. Therefore, the area of the camouflage print portion including the area required for concealment becomes large, which makes the design uncomfortable and makes it easy to infer the concealment position.

Further, it cannot be used as a general-purpose method in a commonly used digital printing method in which a special element is added to ink. Therefore, it is difficult to implement the identification method by adding variable information.

Further, in the method for discriminating printed matter in Patent Document 2, not only is it necessary to prepare a wide variety of inks because information is given to the elements in advance, but also the printing process becomes complicated, so that the ink is erroneously injected. There is a risk of giving personal information.

In order to solve the above-mentioned problems, the present invention is a method for identifying printed matter that identifies information given as an image due to a difference in the shape of minute surface irregularities of an ink film generated by a difference in the penetration time of the ink until the ink is cured. I will provide a.

The present invention uses an ink having photopolymerization properties that cures by irradiating at least a part of a substrate of a porous material having permeability with light of a predetermined wavelength, and the light of a predetermined wavelength is used. It is a method for identifying a printed matter including a print pattern portion consisting of an information addition unit representing information formed at different irradiation timings and a concealing unit arranged around the information addition unit, and is an information addition unit and / or. Focusing on the concealing part, it scans light of the same or different wavelength as the light of a predetermined wavelength, acquires the reflected light from the information giving part and / or the concealing part, converts it into flat image information, and converts it into a flat image. Multiple pieces of information are superimposed to form one composite image information, and the information is read by distinguishing the information addition part from the print pattern part by the difference in surface shape between the information addition part and the concealing part using the composite image information. A method for identifying a characteristic printed matter.

Information can be embedded and read in the printed part by using the principle that the surface shape of the printed part is different depending on the penetrating state of the ink. Since laser light or electron beam is used to give the information, even a minute area Information can be given and it cannot be identified with the naked eye, but it can be read only by a special device, so it is effective as an appraisal identification.

From this, it can be used as a non-destructive authenticity determination method as a preliminary check of security printed matter and certificates suspected of being forged or altered.

It is a figure which shows the outline of the printed matter of this invention. It is an example figure of the printed matter of this invention. It is a figure which shows the schematic diagram of the confocal laser scanning microscope. It is an example figure which shows the Example of the printed matter of this invention.

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 technical ideas described in the claims. ..

The base material used for the printed matter which is the object for carrying out the present invention is a porous material such as paper through which ink permeates. Examples of the porous material include high-quality paper, coated paper, paperboard, synthetic paper, non-woven fabric, ceramics, woven fabric, and composites thereof. As the ink, an ink that is cured by ultraviolet light, visible light, electron beam, or the like is used. As the printing method, letterpress, offset, gravure, flexo, screen, inkjet printing and the like are used.

First, printing is performed on at least a part of the base material by the above-mentioned ink and printing method. In printing, there may be solid printing or a part where printing is not performed in the entire printing area, but in order to effectively carry out the identification method of the present invention, it is easy to clearly confirm the surface shape of the ink. Solid printing is preferable for the surface area.

Next, the printed surface is irradiated with light having a predetermined wavelength at which the ink can be cured to form an information imparting unit (3) representing information (characters, images, etc.). The predetermined wavelength referred to here is not particularly limited as long as the ink can absorb light and carry out polymerization curing such as a laser and an electron beam. After that, the ink on the entire surface of the printed surface is cured with light having a curable wavelength or an electron beam at a slight interval at the timing (timing) of irradiating light with a predetermined wavelength. The interval time is set within a range in which the printed information cannot be discerned by the naked eye, and is adjusted by the printed area, the viscosity of the ink, the porosity of the base material, and the interface energy between the ink and the base material.

After the information is formed and before the entire surface is cured, the ink in the concealing portion (4) that does not form the information permeates. As a result, the surface shape of the ink of the concealing portion (4) that does not form information is different from that of the information giving portion (3) that forms information. The surface shape of the information giving portion (3) to which information is given is smooth, and the surface shape of the concealing portion (4) to which information is not given is uneven. On the contrary, if the concealed portion (4) to which the information is not attached is cured first and the information imparting portion (3) to which the information is attached is cured after the interval time, the surface shape of the negative / positive inversion can be obtained. Hereinafter, in the present embodiment, the printing pattern portion (2) having a configuration in which the information giving portion (3) is cured first, the timing of irradiating the light with an interval is delayed, and then the concealing portion (4) is cured. It is explained as.

The printed area composed of the information addition unit (3) and the concealment unit (4) is referred to as a print pattern unit (2). Since this printed pattern portion (2) is printed with the same ink having photocuring characteristics, it is necessary that the information imparting portion (3) and the concealing portion (4) cannot be distinguished by the naked eye. (4) is arranged around the information giving unit (3) in order to hide the information of the information giving unit (3). Therefore, it is preferable that the concealing part (4) is formed so as to cover the entire circumference of the information giving part (3), but if the information cannot be confirmed with the naked eye, the surrounding of the information giving part (3) is one. It does not have to be adjacent to the part concealing part (4).

Next, the part on which the information is printed is read using a special device. The special device is a surface shape measuring device, a confocal laser scanning microscope, a scanning electron microscope, or the like that can observe the uneven shape of a minute surface. Therefore, it is not necessary to hide the information with another ink or the like. In addition, by using a high-performance laser or electron beam, it is possible to add information to minute parts at the nano level.

(Information added)
1 (a) is a plan view showing the structure of the printed matter (A1) of the present invention, and FIG. 1 (b) is a cross-sectional view taken along the line XX'of FIG. 1 (a). As shown in FIG. 1A, the printed matter (A1) includes a printed pattern portion (2) in a region where at least a part of the base material (1) is printed. This print pattern portion (2) first forms the information imparting portion (3) by photopolymerizing and curing the ink using light of a predetermined wavelength such as laser light, and then until the timing of irradiation with the next light. After setting an interval in time, the entire surface of the printed pattern portion (2) is cured by photopolymerization to form a concealing portion (4) around the information imparting portion (3).

As shown in FIG. 1 (b), the surface of the information-imparting portion (3) on the base material (1) is fairly smooth because it cures instantly after printing, but the other concealing portions (4) are inks. The surface becomes a complicated uneven shape due to the penetration of ink. The information giving unit (3) is an example of the pattern of "A", but the information giving unit (3) is not limited to this in the present invention, and the building shown in FIG. 1 (c). It may be fixed information of patterns such as landscapes, illustrations, characters, and figures, or as shown in FIG. 1 (d), different information in each printed matter, for example, variable information such as personal information and serial number. It is also possible to add information and read it.

For example, as shown in FIG. 2A, in the printed matter (A1), a printed pattern portion (2) is formed on at least a part of the base material (1), and an information giving portion (2) is formed on the printed pattern portion (2). This is an example of a card that forms personal information of a facial image as 3). As shown in FIG. 2B, a printed pattern portion (2) composed of an information giving portion (3) and a concealing portion (4) is formed on the base material (1), and a laminate (14) is further laminated. This is just one example. For convenience of explanation, the information addition part (3) is shown by a dotted line in this specification, but since it is actually the same ink as the concealment part (4), the difference cannot be visually recognized with the naked eye, and the facial image situation is I can't confirm.

The base material (1) used for the printed matter (A1) may be a porous material, and may be high-quality paper, coated paper, paperboard, synthetic paper, non-woven fabric, ceramics, woven fabric, or a composite thereof.

In the case of the surface shape measuring device and the confocal laser scanning microscope, the laser light is transmitted to the printed matter (A1) on which the information addition unit (3) is formed, and the information addition unit (3) is used. As long as the other conditions for observing the difference in surface shape of the concealing portion (4) are satisfied and the laser light can be focused on the information giving portion (3) and the concealing portion (4). Even if the printed matter (A1) is subjected to overcoating or laminating processing, it does not affect the identification at all.

(Information identification method)
For reading the information addition unit (3) of the printed matter (A1), a device capable of observing the three-dimensional shape of the printed ink surface by irradiating with light of a predetermined wavelength is used. For example, a confocal laser scanning microscope, a surface shape measuring device, and a scanning electron microscope are used. Confocal laser scanning microscopes and surface shape measuring devices use laser light for information identification, and scanning electron microscopes use electron beams for information identification. Both methods read information from reflected images of illuminated light or electrons. In this embodiment, the reading principle will be described by taking a confocal laser scanning microscope as an example. FIG. 3 shows a schematic view of a confocal laser scanning microscope.

The laser light from any laser light source (5) mounted on the confocal laser scanning microscope is focused by the lens (6) on the excitation pinhole (7), and the dichroic bead is used. It is reflected in the direction of the scanning device (9) by the transducer (8). The irradiation light is focused on the focal plane (11) through the microscope objective lens (10), and the spot-shaped beam is scanned on the XY plane of the sample.

The specularly reflected light from the sample is introduced into the detector (12). A detection pinhole (13) is arranged in front of the detector (12). The detection pinhole (13) eliminates the specularly reflected light from the out-of-focus surface and introduces only the specularly reflected light from the in-focus area into the detector (12).

The diameter of the pinhole for capturing only the light at the focused point into the detector (12) is set to the optimum size on the computer. The specularly reflected light detected by the detector (12) is converted into planar image information and becomes an XY planar image. After acquiring a continuous XY plane image in the Z direction while moving the stage in the Z direction from this XY plane image, a composite image of one superposed three-dimensional image is reconstructed from each XY plane image to form an uneven structure on the surface. Can be represented as an XY planar image.

It is important that only a very limited number of people know the information on the assignment position and the identification method of the information addition unit (3). However, considering social contributions, for highly public security printed matter such as banknotes, passports, and certificates, the police and customs will be informed of the location and identification method of the information granting department (3). Therefore, it spreads as a non-destructive authenticity discrimination method as a preliminary check.

Hereinafter, specific examples of identification of the printed matter (A1) carried out according to the embodiment for carrying out the above-mentioned invention will be described in detail, but the present invention is not limited to this embodiment.

(Example 1)
Inkjet photography paper was used as the porous material used for the base material (1). After printing the print pattern part (2) on a part of the base material (1) of this inkjet photographic paper using UV-curable IJP cyan ink, the print pattern part (2) is instantly partially UV-cured and called "A". The information giving portion (3) of information was formed, and after a 1-minute interval had elapsed after printing, UV curing was performed to form a concealing portion (4).

Next, a Leica TCS-SP5 was used as a confocal laser scanning microscope (S1) for reading the information addition unit (3) of the created printed matter (A1). A 10x dry lens was used as the microscope objective lens (10), and an argon laser having an excitation wavelength of 514 nm was used as the laser light source (5). The diameter of the detection pinhole (13) was 70.8 μm. The detection wavelength region of the specularly reflected light was set to 510 nm to 520 nm.

FIGS. 4 (a) and 4 (b) show the observation results of the information-imparting unit (3) and the concealing unit (4) by the confocal laser scanning microscope (S1). The confocal scan image of the XY plane was acquired at a resolution of 1024 pixels × 1024 pixels. By raising the stage of the confocal laser scanning microscope (S1), the focus was moved from the surface of the printed matter (A1) to the inside to obtain an XY planar image.

In the information-imparting portion (3) of FIG. 4A, since the ink is cured before the ink permeates after printing, a considerably smooth cured ink film is formed on the substrate. The concealed portion (4) of FIG. 4 (b) has a clearly different shape from the surface of the information imparting portion (3) in which the ink permeates into the concealed portion (4) at an interval of 1 minute after printing and is cured instantly after printing. Unlike this, the surface shows an uneven shape due to the penetration of the ink into the base material (1).

The difference in surface shape between the information giving part (3) and the concealing part (4) cannot be discerned with the naked eye, but if a confocal laser scanning microscope that can observe the surface shape of a minute region is used, information is given due to the difference in the minute surface shape. Information can be read from the difference in surface shape between the portion (3) and the concealing portion (4).

1 Base material 2 Print pattern part 3 Information addition part 4 Concealment part 5 Laser light source 6 Lens 7 Excitation pinhole 8 Dichroic beam splitter-
9 Scanning device 10 Microscope Objective lens 11 Focal plane 12 Detector 13 Detection pinhole 14 Laminate A1 Printed matter S1 Cofocal laser scanning microscope

Claims (1)

Using an ink having photopolymerization characteristics that cures by irradiating at least a part of the substrate of the porous material having permeability with light of a predetermined wavelength, the irradiation timing of the light of the predetermined wavelength is set. It is a method for identifying a printed matter including a print pattern portion including an information giving portion representing information formed differently and a concealing portion arranged around the information giving portion.
Focusing on the information giving portion and / or the concealing portion, the light having the same or different wavelength as the light having the predetermined wavelength is scanned.
The reflected light from the information giving portion and / or the concealing portion is acquired and converted into flat image information.
A plurality of image information on the plane is superposed to form one composite image information.
A method for identifying a printed matter, which comprises reading the information by distinguishing the information imparting portion from the printed pattern portion by the difference in surface shape between the information imparting portion and the concealing portion using the synthetic image information.

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