Anti-counterfeiting printed materials

Abstract

The present invention provides an anti-counterfeiting printed material that exhibits spectral reflectance, has a bright hue in the visible wavelength range, offers minimal hue limitations during design, has high resistance to counterfeiting, and is formed by simple means. [Solution] A printed image is formed by laminating a first printed image and a second printed image on a part of a substrate, the colors of the first printed image and the second printed image are different, the maximum reflectance in the visible wavelength range of the first and second printed images is 40% or more, the average spectral reflectance of the first printed image in the wavelength range of 830nm to 850nm and the wavelength range of 900nm to 950nm is 65% or less, the average spectral reflectance of the second printed image in the wavelength range of 830nm to 850nm is 65% or less, and the average spectral reflectance in the wavelength range of 900nm to 950nm is 90% or more, and the image density of the printed image visible in the wavelength range of 830nm to 850nm and the printed image visible in the wavelength range of 900nm to 950nm are different.

Description

Technical Field

[0001] The present invention relates to a printed matter using a pair of inks having different spectral reflectances in the near-infrared region, and more particularly to a security printed matter in which different images are printed in two different wavelength regions within the near-infrared region.

Background Art

[0002] When a general printing ink is prepared to form a printing area, it is known that the aforementioned printing area absorbs light in the visible wavelength region and transmits light in the infrared wavelength region. Therefore, when producing a security printed matter, a printing area having a function of absorbing light in the infrared wavelength region is formed, and authenticity discrimination is performed by irradiating light in the infrared wavelength region. As a printing ink used to form a printing area having a function of absorbing light in the infrared wavelength region, a printing ink containing carbon black (for example, C.I. Pigment Black 7), which is a material that absorbs light in the near-infrared wavelength region, ITO, or the like is used.

[0003] On the other hand, with the development of printing equipment and digital devices such as printers, color copiers, and scanners, it has become possible to easily produce sophisticated replicas of security printed matters such as valuable printed matters. Therefore, security printed matters with enhanced forgery resistance by various anti-forgery technologies have been proposed.

[0004] Patent Document 1 discloses an anti-counterfeiting printed material in which an image is formed on at least a part of a substrate by a first printed area printed with a first ink and a second printed area printed with a second ink, wherein the first and second printed areas are visible as the same color in the visible light region, the first printed area has a reflectance of 80% or more in the wavelength region of 780 to 1000 nm, the second printed area has a reflectance of 20 to 60% in the wavelength region of 780 to 830 nm and a reflectance of 80% or more in the wavelength region of 900 to 1000 nm, and under a first wavelength in the infrared region, only the second printed area is visible, and under a second wavelength different from the first wavelength, neither the first nor the second printed area is visible.

[0005] Patent Document 2 discloses a thermal transfer material comprising a thermal transfer ink layer formed on a substrate, wherein the thermal transfer ink layer is a layer containing a near-infrared absorbent (excluding carbon black), and the near-infrared absorbent is a phthalocyanine-based compound that absorbs light with a wavelength of 700 nm.

[0006] Patent Document 3, disclosed by the present applicant, discloses an anti-counterfeiting printed material having a titanyl phthalocyanine pigment in the ink used to produce the printed image, with a maximum reflectance of 40% or more in the visible wavelength region, an average spectral reflectance of 85% or more in the wavelength region of 900 nm to 950 nm, and a printing region in which the average spectral reflectance in the wavelength region of 830 nm to 850 nm is 30% or more lower than the average spectral reflectance in the wavelength region of 900 nm to 950 nm. [Prior art documents] [Patent Documents]

[0007] [Patent Document 1] Japanese Patent Publication No. 2011-178009 [Patent Document 2] Japanese Patent Application Publication No. 1-30788 [Patent Document 3] Patent Application No. 2023-156598 [Overview of the Initiative] [Problems that the invention aims to solve]

[0008] To date, many anti-counterfeiting printed materials have been known to use ink compositions containing carbon black, which exhibits absorption in the infrared region. Anti-counterfeiting printed materials formed from such ink compositions exhibit absorption across the entire wavelength range from the visible wavelength region to the near-infrared region. As a result, when the printed layer is viewed in the visible wavelength region, it tends to appear in a dark hue, which imposes design constraints. Furthermore, since it always exhibits absorption at all wavelengths in the infrared region, it is easy to determine whether it is genuine or not. Moreover, carbon black is readily available as a commercially available product, and the production of printed materials is easy, which has led to a weakening of its resistance to counterfeiting.

[0009] The technology described in Patent Document 1, as a method that does not use carbon black, involves formulating ink with a green pigment having a special spectral wavelength to produce a printed image, which has the problem that the hue of the printed image is limited to green.

[0010] Furthermore, the technology described in Patent Document 2 also involves incorporating phthalocyanine-based dyes into the ink to create printed images, which are absorbed in the near-infrared region. However, this has the same effect as when a small amount of carbon black is incorporated, resulting in the problem of low resistance to counterfeiting.

[0011] Furthermore, the technology described in Patent Document 3 has extremely high resistance to counterfeiting because it changes from absorption to transmission in the near-infrared region, but it has the problem that if the material is obtained, the infrared function can be reproduced.

[0012] The problem that this invention aims to solve is to provide an anti-counterfeiting printed material with improved resistance to counterfeiting by reducing the hue restrictions during design and by applying changes in brightness, saturation, or hue based on wavelength to the image observed in the infrared region. [Means for solving the problem]

[0013] As a result of diligent research to solve the above problems, we have found that the above problems can be solved by using anti-counterfeiting printed materials having a printed image in which the maximum reflectance in the visible wavelength region is within a specific range and the average spectral reflectance in two infrared wavelength regions is within a specific range, and thus we have completed the present invention.

[0014] The present invention relates to an anti-counterfeiting printed material having a printed image consisting of a first printed image and a second printed image formed on at least a portion of a substrate, wherein the first printed image and the second printed image are laminated, the colors of the first printed image and the second printed image are different, the maximum reflectance of the first printed image and the second printed image in the visible wavelength region is 40% or more, the first printed image has an average spectral reflectance of 65% or less in the wavelength region of 830nm to 850nm and the wavelength region of 900nm to 950nm, the second printed image has an average spectral reflectance of 65% or less in the wavelength region of 830nm to 850nm and an average spectral reflectance of 90% or more in the wavelength region of 900nm to 950nm, and the image density of the printed image visible in the wavelength region of 830nm to 850nm and the printed image visible in the wavelength region of 900nm to 950nm are different. [Effects of the Invention]

[0015] This invention provides anti-counterfeiting printed materials with improved resistance to counterfeiting by reducing the hue limitations during design and by applying wavelength-dependent variations to images observed in the infrared region.

[0016] Furthermore, by comparing the average spectral reflectance in two infrared wavelength regions with the printed image, or by comparing the printed image as visible with an infrared visualization device, it is possible to provide anti-counterfeiting printed materials that can be easily authenticated. [Brief explanation of the drawing]

[0017] [Figure 1] A figure showing an anti-counterfeiting printed material S, which is an embodiment of the present invention. [Figure 2]Figure showing the printed image of the present invention visually recognized in the visible wavelength region. [Figure 3] Figure showing the first printed image and the second printed image constituting the printed image of the present invention visually recognized in the visible wavelength region. [Figure 4] Figure showing the printed image of the present invention visually recognized at a wavelength of 830 nm by an infrared visualization device. [Figure 5] Figure showing the printed image of the present invention visually recognized at a wavelength of 940 nm by an infrared visualization device. [Figure 6] Figure showing the spectral reflectance when the first printed image of the present invention is red and the second printed image is blue. [Figure 7] Figure showing the spectral reflectance when the first printed image of the present invention is blue and the second printed image is yellow. [Figure 8] Figure showing the spectral reflectance when the first printed image of the present invention is yellow and the second printed image is red. [Figure 9] Figure showing the spectral reflectance of Comparative Example 1. [Figure 10] Figure showing the printed image of Comparative Example 1 visually recognized in the visible wavelength region. [Figure 11] Figure showing the printed image of Comparative Example 1 visually recognized at a wavelength of 830 nm by an infrared visualization device. [Figure 12] Figure showing the printed image of Comparative Example 1 visually recognized at a wavelength of 940 nm by an infrared visualization device. [Figure 13] Figure showing the spectral reflectance of Comparative Example 2. [Figure 14] Figure showing the printed image of Comparative Example 2 visually recognized in the visible wavelength region. [Figure 15] Figure showing the printed image of Comparative Example 2 visually recognized at a wavelength of 830 nm by an infrared visualization device. [Figure 16] Figure showing the printed image of Comparative Example 2 visually recognized at a wavelength of 940 nm by an infrared visualization device.

Embodiments for Carrying Out the Invention

[0018] Hereinafter, the present invention will be described in detail. An embodiment of the present invention is an anti-counterfeiting printed matter S.

[0019] It should be noted that the present invention is not limited to the following embodiments, and should be understood to include various other embodiments as long as they fall within the scope of the technical idea described in the claims.

[0020] [Anti-counterfeiting print S] The anti-counterfeiting printed material S according to an embodiment of the present invention has a printed image P formed on a substrate B, as shown in Figure 1. Figure 2 is an enlarged view of the printed image P, and Figure 3 shows the configuration of the printed image P in Figure 2. Figure 3(a) is the first printed image P1, and Figure 3(b) is the second printed image P2. Since the second printed image P2 is provided within the area of ​​the first printed image P1, the first printed image P1 and the second printed image P2 are stacked on top of each other. In this case, by using different colors and narrowing the line width of the first printed image P1 and the second printed image P2, the printed image P can be visually perceived as a composite color of the colors of the first printed image P1 and the second printed image P2. Note that since it is difficult to match the colors of each printed line of the first printed image P1 and the second printed image P2, different colors or similar colors are preferable. For this reason, "different colors" in the present invention also include similar colors. Furthermore, while the printed image P is indicated by a number, there are no particular limitations; you can choose any text, mark, or design as you see fit.

[0021] For the line design of the first printed image P1 and the second printed image P2, the lower limit of the line width for the contour lines and lines within the contour lines of the first printed image P1 and the lines of the second printed image P2 is 0.1 mm, and the line pitch is 0.2 mm, with a line width of 0.2 mm and a line pitch of 0.4 mm or more being preferable.

[0022] <Reflectance in each wavelength range> Next, we will explain the spectral reflectance in each wavelength range of the first printed image P1 and the second printed image P2.

[0023] (Maximum reflectance in the visible light wavelength range) The maximum reflectance in the visible wavelength region of the first printed image P1 and the second printed image P2 is 40% or more. Preferably it is 50% or more, more preferably 60% or more, and even more preferably 65% ​​or more.

[0024] If the maximum reflectance in the visible wavelength range is 40% or less, the hue of the printed image P will become darker in the visible wavelength range, which may restrict the design colors and limit the freedom of color. Also, if the ink used for the printed image P contains carbon black and absorbs in the infrared wavelength range, the reflectance in the visible wavelength range will be 40% or less. Therefore, if the maximum reflectance is 40% or more, a difference will be created compared to printed images containing carbon black, allowing for greater differentiation.

[0025] Furthermore, if the maximum reflectance in the visible wavelength range is 40% or higher, the hue of the printed image P becomes brighter in the visible wavelength range, allowing for greater freedom of color without being restricted by design colors. In addition, since the printed image P can have a hue similar to that of inks normally used in printing, it is difficult for people to detect that anti-counterfeiting measures have been taken.

[0026] In the present invention, the "visible wavelength region" has a lower limit of wavelength range of 360 nm to 400 nm, preferably 380 nm, and more preferably 400 nm, and an upper limit of wavelength range of 760 nm to 830 nm, preferably 800 nm, and more preferably 760 nm.

[0027] The maximum reflectance in the visible wavelength region can be obtained by measuring it using a spectrophotometer.

[0028] (Average spectral reflectance in the wavelength range of 830nm to 850nm) Next, the average spectral reflectance of the first printed image P1 and the second printed image P2 in the wavelength range of 830 nm to 850 nm will be described. The average spectral reflectance of the first printed image P1 and the second printed image P2 in the wavelength range of 830 nm to 850 nm is 65% or less. Preferably it is 60% or less, and more preferably 55% or less. When the average spectral reflectance is 65% or less, it is in the relative absorption region, and therefore when viewed with an infrared visualization device, it can be seen as a blackish color.

[0029] The average spectral reflectance in the wavelength range of 830 nm to 850 nm can be obtained by using a spectrophotometer to measure the spectral reflectance at predetermined wavelength intervals, preferably 1 nm intervals, starting from 830 nm, and then calculating the average value of the spectral reflectance.

[0030] (Average spectral reflectance in the wavelength range of 900nm to 950nm) Next, we will explain the average spectral reflectance of the first printed image P1 and the second printed image P2 in the wavelength range of 900 nm to 950 nm. First, the average spectral reflectance of the first printed image P1 in the wavelength range of 900 nm to 950 nm is 90% or more. Preferably, it is 95% or more. When the average spectral reflectance is 90% or more, it is a relatively reflective region, and therefore, when viewed with an infrared visualization device, it will be seen as a white-ish color.

[0031] On the other hand, the average spectral reflectance of the second printed image P2 in the wavelength range of 900 nm to 950 nm is 65% or less. Preferably it is 60% or less, and more preferably 55% or less. When the average spectral reflectance is 65% or less, it is in a relatively absorbent region, and therefore, when viewed with an infrared visualization device, it can be seen as a blackish color.

[0032] The average spectral reflectance in the wavelength range of 900 nm to 950 nm can be obtained by using a spectrophotometer to measure the spectral reflectance at predetermined wavelength intervals, preferably 1 nm intervals, starting from 900 nm, and then calculating the average value of the spectral reflectance.

[0033] Therefore, when the printed image P is viewed with an infrared visualization device, as shown in Figure 4, in the wavelength range of 830nm to 850nm, both the first printed image P1 and the second printed image P2 appear as blackish tones. Furthermore, in the wavelength range of 900nm to 950nm, as shown in Figure 5, the first printed image P1 appears as a blackish tone, while the second printed image P2 appears as white. Thus, although the printed image P appears as a blackish hue in both the wavelength range of 830nm to 850nm and the wavelength range of 900nm to 950nm, the density of the blackish printed image that can be viewed differs between the two ranges, making it easy to determine whether the image is genuine or not.

[0034] (Adjustment of the reflectivity of the first printed image P1 and the second printed image P2) The method for adjusting the maximum reflectance in the visible wavelength region, the average spectral reflectance in the wavelength region of 830 nm to 850 nm, and the average spectral reflectance in the wavelength region of 900 nm to 950 nm of the first printed image P1 and the second printed image P2 to a predetermined range is not particularly limited.

[0035] Furthermore, as a means to achieve a maximum reflectance of 40% or more in the visible wavelength region in the first printed image P1 and the second printed image P2, one example is to use an ink composition in which the amount of dark-colored components such as black in the visible wavelength region is suppressed as the ink composition that forms the printed image P.

[0036] Next, as a means to ensure that the first printed image P1 does not appear dark in the visible wavelength region, and that the average spectral reflectance in the wavelength region of 830nm to 850nm is 65% or less, and the average spectral reflectance in the wavelength region of 900nm to 950nm is 65% or less, some blue pigments and some green pigments, in particular phthalocyanine pigments. On the other hand, as a means to ensure that the second printed image P2 does not appear dark in the visible wavelength region, and that the average spectral reflectance in the wavelength region of 830nm to 850nm is 65% or less, and the average spectral reflectance in the wavelength region of 900nm to 950nm is 90% or more, some blue pigments and some green pigments, in particular titanyl phthalocyanine pigments. Note that the configurations of the first printed image P1 and the second printed image P2 may be reversed.

[0037] <Specific examples of anti-counterfeiting printed materials S> Figure 1 shows a specific example of an anti-counterfeiting printed material S according to an embodiment of the present invention. As shown in Figure 1, the anti-counterfeiting printed material S has a printed image P printed on a part of the substrate B. Figure 2 is an enlarged view of the printed image P, and Figure 3 shows the composition of the printed image P in Figure 2, which consists of a first printed image P1 and a second printed image P2. For example, the first printed image P1 in Figure 3(a) consists of the outline of "1000" and lines in the lower left direction, and the second printed image P2 in Figure 3(b) consists of lines in the lower right direction, with the line area ratio of the printed lines in the lower left and lower right directions being approximately the same. There are no particular restrictions on the form of the first and second printed images, and they can be appropriately selected from straight lines, curves, arcs, halftones, substrate patterns, etc.

[0038] In the embodiment of the present invention, the anti-counterfeiting printed material S allows the printed image P (the "1000" design in Figures 1 and 2) to be visible in vivid colors within the visible wavelength range.

[0039] (Example using printed image P in purple) In Figure 1, the first printed image P1 of the anti-counterfeiting printed material S is red, and the second printed image P2 is blue. The printed image P of the anti-counterfeiting printed material S is visible as a composite color of purple. Figure 6 shows the spectral reflectance of the first printed image P1 and the second printed image P2, with the solid line representing the first printed image P1 and the dotted line representing the second printed image P2.

[0040] In the visible wavelength range, the first printed image P1, which is red, has a reflectivity characteristic of red (wavelength 620nm) of 77%, and the second printed image P2, which is blue, has a reflectivity characteristic of blue (wavelength 470nm) of 60%. Therefore, since both the first printed image P1 and the second printed image P2 are bright hues, the purple color of the combined printed image P is also visible as a bright hue.

[0041] Furthermore, the average spectral reflectance in the wavelength range of 830 nm to 850 nm is 57% for the first printed image P1 and 62% for the second printed image P2. Therefore, as shown in Figure 4, when the first printed image P1 and the second printed image P2 are viewed using an infrared visualization device, they appear as dark colors, and thus the printed image P can be viewed as a dark color.

[0042] Furthermore, the average spectral reflectance in the wavelength range of 900nm to 950nm is 65% for the first printed image P1 and 95% for the second printed image P2, resulting in a 30% difference. Therefore, as shown in Figure 5, when the first printed image P1 is viewed using an infrared visualization device, it appears as a black color, and when the second printed image P2 is viewed, it appears as a white color, so printed image P appears as a black color. However, compared to the wavelength range of 830nm to 850nm, the first printed image P1 appears as a white color, resulting in approximately half the image density of the black color (image density of printed image P2 only). Therefore, a clear difference in the density of printed images occurs between the wavelength range of 830nm to 850nm and the wavelength range of 900nm to 950nm, making it easy to determine authenticity.

[0043] (Example with printed image P shown in green) In Figure 1, the first printed image P1 of the anti-counterfeiting printed material S is blue, and the second printed image P2 is yellow. The printed image P of the anti-counterfeiting printed material S is visible as a composite color in green. Figure 7 shows the spectral reflectance of the first printed image P1 and the second printed image P2, with the solid line representing the first printed image P1 and the dotted line representing the second printed image P2.

[0044] In the visible wavelength range, the first blue printed image P1 exhibits a reflectivity characteristic unique to blue (wavelength 470 nm) of 63%, while the second yellow printed image P2 exhibits a reflectivity characteristic unique to yellow (wavelength 510 nm) of 64%. Therefore, since both the first and second printed images P1 and P2 are bright hues, the green color of the combined and visible printed image P is also visible as a bright hue.

[0045] Furthermore, the average spectral reflectance in the wavelength range of 830 nm to 850 nm is 59% for the first printed image P1 and 60% for the second printed image P2. Therefore, as shown in Figure 4, when the first printed image P1 and the second printed image P2 are viewed using an infrared visualization device, they appear as dark colors, and thus the printed image P can be viewed as a dark color.

[0046] Furthermore, the average spectral reflectance in the wavelength range of 900nm to 950nm is 63% for the first printed image P1 and 95% for the second printed image P2, resulting in a difference of 32%. Therefore, as shown in Figure 5, when the first printed image P1 is viewed using an infrared visualization device, it appears as a black color, and when the second printed image P2 is viewed, it appears as a white color, so printed image P appears as a black color. However, compared to the wavelength range of 830nm to 850nm, the first printed image P1 appears as a white color, resulting in an image density of approximately half that of the black color (image density of printed image P2 only). Therefore, there is a clear difference in the density of the printed images between the wavelength range of 830nm to 850nm and the wavelength range of 900nm to 950nm, making it easy to determine authenticity.

[0047] (Example using orange for printed image P) In Figure 1, the first printed image P1 of the anti-counterfeiting printed material S is yellow, and the second printed image P2 is red, so the printed image P of the anti-counterfeiting printed material S is visible as an orange composite color. Figure 8 shows the spectral reflectance of the first printed image P1 and the second printed image P2, with the solid line representing the first printed image P1 and the dotted line representing the second printed image P2.

[0048] In the visible wavelength region, the first printed image P1, which is yellow, has a reflectivity characteristic of yellow (wavelength 510 nm) of 64%, and the second printed image P2, which is red, has a reflectivity characteristic of red (wavelength 620 nm) of 61%. Therefore, since both the first printed image P1 and the second printed image P2 are bright hues, the orange color of the combined printed image P is also visible as a bright hue.

[0049] Furthermore, the average spectral reflectance in the wavelength range of 830 nm to 850 nm is 59% for the first printed image P1 and 61% for the second printed image P2. Therefore, as shown in Figure 4, when the first printed image P1 and the second printed image P2 are viewed using an infrared visualization device, they appear as dark colors, and thus the printed image P can be viewed as a dark color.

[0050] Furthermore, the average spectral reflectance in the wavelength range of 900nm to 950nm is 64% for the first printed image P1 and 96% for the second printed image P2, resulting in a difference of 32%. Therefore, as shown in Figure 5, when the first printed image P1 is viewed using an infrared visualization device, it appears as a black color, and when the second printed image P2 is viewed, it appears as a white color, so printed image P appears as a black color. However, compared to the wavelength range of 830nm to 850nm, the first printed image P1 appears as a white color, resulting in an image density of approximately half that of the black color (image density of printed image P2 only). Therefore, a clear difference in the density of printed images occurs between the wavelength range of 830nm to 850nm and the wavelength range of 900nm to 950nm, making it easy to distinguish between genuine and fake. In this embodiment of the present invention, a combination of red, blue, and yellow has been described, but other colors may be used.

[0051] <Authenticity determination method> The anti-counterfeiting printed material S according to the embodiment of the present invention can be used to determine authenticity by utilizing the characteristic spectral reflectance characteristics of the printed image P in the visible wavelength region and the infrared wavelength region.

[0052] In determining the authenticity of the anti-counterfeiting printed material S of the present invention, the printed image P is viewed using an infrared visualization device in the wavelength range of 830nm to 850nm and then in the wavelength range of 900nm to 950nm. The difference in the visible printed image can then be confirmed to determine its authenticity. Specifically, when the printed image P is viewed using an infrared visualization device, the printed image in the wavelength range of 830nm to 850nm shown in Figure 4 and the printed image in the wavelength range of 900nm to 950nm shown in Figure 5 are different, making it easy to determine its authenticity.

[0053] For determining the authenticity of a printed image P, an infrared visualization device such as an infrared camera, CCD, or CMOS sensor can be used.

[0054] In addition, infrared monitors and general image sensors can be used. To read only a specific wavelength range, a filter that cuts out visible light and a light source that emits only light of a specific wavelength (such as an infrared LED) can be used in combination with the image sensor, or a bandpass filter that transmits only light of a specific wavelength and a light source that emits near-infrared light (such as an incandescent light bulb) can be used.

[0055] <Application> The anti-counterfeiting printed material S according to an embodiment of the present invention can be used as various printed materials that require anti-counterfeiting measures. In particular, it can be used as security printed materials that require advanced anti-counterfeiting technology or printed materials that require aesthetic appeal, such as banknotes, revenue stamps, postage stamps, gift certificates, monetary vouchers, admission tickets, securities, various certificates, passports, security labels, etc.

[0056] <Printing method / base material S> The printing method used to produce the anti-counterfeiting printed material S according to the embodiment of the present invention is not particularly limited. For example, printing methods such as offset printing (offset printing with dampening solution, offset printing without dampening solution), intaglio printing, relief printing, lithographic printing, stencil printing, letterpress printing, screen printing, gravure printing, flexographic printing, electrophotographic printing, and inkjet printing can be used. When printing the anti-counterfeiting printed material S, one of these printing methods may be used alone, or two or more printing methods may be used.

[0057] The base material B used in producing the anti-counterfeiting printed material S according to an embodiment of the present invention is not particularly limited. A base material B of any shape, such as a sheet or a three-dimensional shape, can be used. Examples of materials constituting the base material B include paper, plastic, metal, glass, ceramic, wood, and composites of two or more of these materials. However, it is preferable to use a material that reflects infrared rays for the base material B.

[0058] [Printing ink] In the anti-counterfeiting printed material S according to an embodiment of the present invention, the first printing ink that forms the first printed image P1 has a maximum reflectance of 40% or more in the visible wavelength region, an average spectral reflectance of 65% or less in the wavelength region of 830 nm to 850 nm, and an average spectral reflectance of 65% or less in the wavelength region of 900 nm to 950 nm. On the other hand, the second printing ink that forms the second printed image P2 has a maximum reflectance of 40% or more in the visible wavelength region, an average spectral reflectance of 65% or less in the wavelength region of 830 nm to 850 nm, and an average spectral reflectance of 90% or more in the wavelength region of 900 nm to 950 nm. The ink composition is not particularly limited as long as it contains at least one coloring agent.

[0059] The first and second printing inks contain at least one colorant, a varnish, and optionally an auxiliary agent.

[0060] The first printing ink of the present invention is preferably an ink composition containing at least one colorant, which includes a phthalocyanine-based pigment. Furthermore, the content of the phthalocyanine-based pigment is preferably 0.3% by mass or more and 25% by mass or less, based on the total amount of the ink composition.

[0061] As a phthalocyanine-based pigment, it is preferable that the compound is represented by the following formula (1).

[0062] (chemical 1) TIFF2026055579000002.tif75109 (In formula (1), M is one of Mg, Al, Ti, V, Cr, Mn, Fe, Co, Ni, Zn, Ga, Mo, Ru, Pd, In, Sn, Sb, Bi, La, or Ce, and R11 to R44 may be the same or different from each other, for example, hydrogen, halogen, alkyl group, alkoxy group, cycloalkyl group, alkynyl group, aryl group, arylalkyl group, aryloxy group, heteroaryl group, acyl group, carboxyl group, hydroxyl group, amino group, sulfonic acid group, nitro group, etc., and may have substituents, and two or more may be bonded together to form a ring.)

[0063] <Compound represented by formula (1)> In the present invention, the compound represented by formula (1) is not particularly limited. For example, one or more compounds selected from the group consisting of phthalocyanine derivatives (e.g., formula (1-1) below), naphthalocyanine derivatives (e.g., formula (1-2) below), and anthracocyanine derivatives (e.g., formula (1-3) below) may be used. (chemical 1-1, 1-2, 1-3) TIFF2026055579000003.tif52114

[0064] In formula (1), M is one of Mg, Al, Ti, V, Cr, Mn, Fe, Co, Ni, Zn, Ga, Mo, Ru, Pd, In, Sn, Sb, Bi, La, or Ce. Of these, M is preferably one of Mg, Al, Ti, V, Cr, Mn, Fe, Co, Ni, Zn, In, Sn, La, or Ce, more preferably one of Mg, Al, Ti, Cr, Mn, Fe, Co, Ni, Zn, or Sn, and even more preferably one of Mg, Al, Mn, Fe, Co, Ni, Zn, or Sn.

[0065] In formula (1), R11 to R44 may be the same or different from each other, and may be, for example, hydrogen, halogen, alkyl group, alkoxy group, cycloalkyl group, alkynyl group, aryl group, arylalkyl group, aryloxy group, heteroaryl group, acyl group, carboxyl group, hydroxyl group, amino group, sulfonic acid group, nitro group, etc. These may have substituents, and two or more may be bonded together to form a ring. In formula (1), when R12 and R13, R22 and R23, R32 and R33 and R42 and R43 are bonded together to form a ring, a naphthalocyanine derivative or anthracocyanine derivative is obtained.

[0066] Among R11 to R44, alkyl groups include, for example, alkyl groups having 1 to 24 carbon atoms. Specifically, examples include methyl group, ethyl group, n-propyl group, isopropyl group, n-butyl group, isobutyl group, tert-butyl group, pentyl group, hexyl group, octyl group, etc. Among R11 to R44, alkoxy groups include, for example, alkoxy groups having 1 to 24 carbon atoms. Specifically, examples include methoxy group, ethoxy group, n-propoxy group, isopropoxy group, n-butoxy group, isobutoxy group, tert-butoxy group, pentyloxy group, hexyloxy group, octyloxy group, etc. Among R11 to R44, cycloalkyl groups include, for example, cycloalkyl groups having 3 to 24 carbon atoms. Specifically, examples include cyclopropyloxy group, cyclobutyloxy group, cyclopentyloxy group, cyclohexyloxy group, etc. Among R11 to R44, examples of alkenyl groups include alkenyl groups having 1 to 24 carbon atoms. Specifically, examples include ethenyl, propenyl, butenyl, pentenyl, hexenyl, and octenyl groups. Among R11 to R44, examples of alkynyl groups include alkynyl groups having 1 to 24 carbon atoms.

[0067] Specifically, examples include ethynyl group, propynyl group, butynyl group, pentynyl group, hexynyl group, octinyl group, etc. Among R11 to R44, examples of aryl groups include aryl groups having 5 to 24 carbon atoms. Specifically, examples include phenyl group, naphthyl group, biphenyl group, etc. Among R11 to R44, examples of arylalkyl groups include arylalkyl groups having 7 to 24 carbon atoms.

[0068] Specifically, examples include monophenylmethyl group, monophenylpropyl group, triphenylmethyl group, etc. Among R11 to R44, examples of aryloxy groups include aryloxy groups having 5 to 24 carbon atoms. Specifically, examples include phenoxy group, naphthyloxy group, biphenyloxy group, etc. Among R11 to R44, examples of heteroaryl groups include heteroaryl groups having 4 to 24 carbon atoms. Specifically, examples include thiophenyl group, furanyl group, carbazole group, benzothiophenyl group, benzofuranyl group, indolyl group, pyrrolyl group, pyridyl group, etc. Among R11 to R44, examples of acyl groups include acyl groups having 1 to 24 carbon atoms.

[0069] Specifically, examples include acetyl groups, propionyl groups, butanoyl groups, pentanoyl groups, and heptanoyl groups. Among R11 to R44, examples of amino groups include amino groups with 0 to 24 carbon atoms. Specifically, examples include amino groups (-NH2 groups), methylamino groups, dimethylamino groups, and diphenylamino groups.

[0070] Examples of substituents that R11 to R44 may have include one or more selected from the group consisting of halogens, alkyl groups, alkoxy groups, cycloalkyl groups, alkynyl groups, aryl groups, arylalkyl groups, aryloxy groups, heteroaryl groups, acyl groups, carboxyl groups, hydroxyl groups, amino groups, sulfonic acid groups, or nitro groups. These substituents can be the same as those for R11 to R44. The substituents may be crosslinked with each other, and the substituents as a whole may form a cyclic structure (aromatic group). Substituents may have further substituents.

[0071] Preferably, the compound represented by formula (1) is one that is transparent to visible light, has high reflectivity in the wavelength range of 500 nm to 600 nm, and exhibits absorption in the range of 780 nm to 1000 nm. By having absorption in the near-infrared region below 1000 nm, it becomes possible to produce near-infrared absorption prints with high saturation that cannot be achieved with near-infrared absorption prints using common near-infrared absorption materials such as carbon black or Prussian blue. Examples of compounds represented by formula (1) that exhibit such properties include suzunaphthalocyanine.

[0072] On the other hand, the second printing ink of the present invention is preferably an ink composition containing at least one colorant, which includes a titanyl phthalocyanine-based pigment. Furthermore, the content of the titanyl phthalocyanine-based pigment is preferably 0.3% by mass or more and 25% by mass or less, based on the total amount of the ink composition.

[0073] As for the titanylphthalocyanine pigment, it is preferable that it be a compound represented by the following formula (2).

[0074] (Case 2) TIFF2026055579000004.tif5458 (In formula (2), X 1 , X 2 , X 3 and X 4 These are a halogen atom, an alkyl group, an alkoxy group, a cyano group, or a nitro group, and may be the same or different. a, b, c, and d are integers between 0 and 4, and may be the same or different. If a, b, c, and d are integers between 2 and 4, multiple X 1 , X 2 , X 3 and X 4 These may be the same or different.

[0075] Titanylphthalocyanine pigments are themselves pale blue pigments. In the present invention, the titanylphthalocyanine pigment is preferably titanylphthalocyanine in which a, b, c, and d in formula (2) above are all 0. The crystalline form of titanylphthalocyanine is not particularly limited. Any crystalline form such as Y-type, A-type (β-type), or B-type (α-type) can be used, and Y-type titanylphthalocyanine or B-type titanylphthalocyanine is preferred. Titanylphthalocyanine can be either a synthetic product or a commercially available product.

[0076] <Coloring agent> The compositions required for the first and second printing inks are described below. The colorants are not particularly limited as long as they are components that can color the ink composition to a desired hue. Examples include inorganic colorants, organic colorants, brightening pigments, dyes, fluorescent pigments, extender pigments, etc., in colors such as red, blue, yellow, green, purple, black, white, and orange. The particle surfaces of the colorants may be treated with surface treatment agents such as rosin compounds, silane coupling agents, resins, and pigment derivatives, as needed. In the present invention, the ink composition contains two or more colorants.

[0077] Examples of inorganic coloring pigments include carbon black, iron black, titanium dioxide, zinc oxide, zinc yellow, red iron oxide, yellow iron oxide, ultramarine, Prussian blue, chromium oxide green, cobalt green, and composite oxides (nickel-titanium, chromium-titanium, bismuth-vanadium, cobalt-aluminum, cobalt-aluminum-chromium, ultramarine blue). These may be used individually or in combination of two or more.

[0078] Examples of organic coloring pigments include phthalocyanine pigments, azo pigments, quinacridone pigments, anthraquinone pigments, dioxane pigments, indigo pigments, thioindigo pigments, perinone pigments, perylene pigments, indoline pigments, azomethine pigments, isoindolinone pigments, isoindoline pigments, dioxazine pigments, quinophthalone pigments, metal complex pigments, diketopyrrolopyrrole pigments, polycyclic pigments, surene pigments, benzimidazolon pigments, anthrapyrimidine pigments, nitro pigments, nitroso pigments, and aniline black.

[0079] Examples of luminous pigments include metal powders and foils such as aluminum, copper, zinc, tin, brass, and silver; oxide-coated mica such as titanium dioxide-coated mica; oxide-coated glass flakes; fish scale foil; bismuth oxychloride; and pigments having pearlescent or interference luster. These may be used individually or in combination of two or more types.

[0080] Examples of dyes include water-soluble dyes, oil-soluble dyes, or disperse dyes of colors such as red, blue, yellow, green, purple, black, white, and orange. The dyes may be acid dyes, basic dyes, reactive dyes, direct dyes, or food dyes. These may be used individually or in combination of two or more.

[0081] Examples of fluorescent pigments include pigments that use light in a specific wavelength range as excitation energy and emit light in a wavelength range different from the aforementioned wavelengths.

[0082] Examples of extender pigments include talc, mica, barium sulfate, clay, calcium carbonate, kaolinite, silicon dioxide, bentonite, heavy calcium carbonate, barium carbonate, zirconia, and alumina. These may be used individually or in combination of two or more. The volume-average particle size of the extender pigments can be approximately 0.001 to 100 μm.

[0083] <Varnish> The varnish that constitutes the ink composition is composed of a binder and a liquid component that dissolves or disperses the binder, and after printing, it forms an ink coating film that constitutes the printed image P.

[0084] <Binder> Examples of binders include resins and curable compounds having ethylenically unsaturated bonds, which are used as binders and binders in the field of ink compositions. These may be used individually or in combination of two or more.

[0085] Examples of resins include acrylic resins, polyester resins, styrene resins, polyolefin resins, epoxy resins, polyurethane resins, phenolic resins, rosin resins, alkyd resins, petroleum resins, and hydrocarbon resins. The weight-average molecular weight of these resins can be, for example, between 500 and 1,000,000.

[0086] Examples of curable compounds having ethylenically unsaturated bonds include monofunctional monomers having one ethylenically unsaturated bond in the molecule, and bifunctional or more functional monomers having two or more ethylenically unsaturated bonds in the molecule, which can polymerize and cure ink compositions by light, heat, etc. These may be used individually or in combination of two or more.

[0087] The binder content is not particularly limited. For example, it can be 5% by mass or more and 60% by mass or less, relative to the total amount of the ink composition.

[0088] <Liquid component> The liquid component that forms the varnish is a liquid component that has been used in the preparation of ink compositions to date, and is used to dissolve resins to form varnish or to adjust the viscosity of ink compositions. Examples of liquid components are those that are in a liquid state at printing temperatures (usually 10°C to 40°C), and include organic solvents (e.g., ketone solvents, halogen solvents, hydrocarbon solvents, petroleum solvents, ether solvents, ester solvents, glycol ether solvents, amide solvents, etc.), animal and vegetable oils, animal and vegetable oil derivatives, mineral oils, and water. These may be used individually or in combination of two or more.

[0089] <Auxiliary agent> The ink composition for forming the anti-counterfeiting printed material S of the present invention may optionally contain auxiliary agents. These auxiliary agents are not particularly limited as long as they are used as auxiliary agents for printing inks. Examples include dispersants, surfactants, drying agents, waxes, gelling agents, viscosity modifiers, antioxidants, and bactericidal / fungal agents. These may be used individually or in combination of two or more.

[0090] The dispersant may be any of anionic, cationic, amphoteric, or nonionic dispersants, and examples include polymer dispersants, low molecular weight compounds (surfactants), and pigment derivatives. These may be used individually or in combination of two or more.

[0091] Examples of surfactants include anionic surfactants, nonionic surfactants, cationic surfactants, amphoteric surfactants, fluorinated surfactants, and silicone surfactants. These may be used individually or in combination of two or more.

[0092] Examples of desiccants include metal dryers formed from various metals and higher fatty acids. These may be used individually or in combination of two or more types.

[0093] Examples of waxes include plant-based waxes, animal-based waxes, petroleum-based waxes, and synthetic waxes. These may be used individually or in combination of two or more types.

[0094] Examples of gelling agents include metal chelate compounds, organic acid metal salts (metal soaps), and metal soap oligomers.

[0095] Examples of viscosity modifiers include the aforementioned animal and vegetable oils and / or derivatives of animal and vegetable oils, polyvinyl alcohol, cellulose compounds, polyamines, polyimines, starch compounds, alginic acid compounds, fatty acid ester compounds, polyacrylic acid compounds, and the like. These may be used individually or in combination of two or more.

[0096] Examples of antioxidants include phenolic antioxidants, amine antioxidants, sulfur-based antioxidants, and phosphorus-based antioxidants. These may be used individually or in combination of two or more.

[0097] Examples of disinfectants and fungicides include sodium dehydroacetate, sodium benzoate, sodium pyridinethion-1-oxide, p-hydroxybenzoate ethyl ester, 1,2-benzisothiazolin-3-one, and their salts. These may be used individually or in combination of two or more. [Examples]

[0098] The present invention will be described in more detail below with reference to examples, but the present invention is not limited thereto. In each example, "parts" refers to parts by mass, and "%" refers to mass percent.

[0099] In Examples 1 to 3, the "average spectral reflectance in the wavelength range of 830 nm to 850 nm" was approximately the same as the "spectral reflectance at a wavelength of 830 nm," so the value of the "spectral reflectance at a wavelength of 830 nm" was used.

[0100] In Examples 1-3 and the Comparative Example, the "average spectral reflectance in the wavelength range of 900 nm to 950 nm" was approximately the same as the "spectral reflectance at a wavelength of 940 nm," so the value of the "spectral reflectance at a wavelength of 940 nm" was used.

[0101] In Examples 1-3, CIPigment Blue 15:3 was used as the blue coloring agent, CIPigment Red 185 as the red coloring agent, and CIPigment Yellow 180 as the yellow coloring agent.

[0102] Furthermore, in Examples 1 to 3, the printed image P in Figure 1 is composed of the first printed image P1 shown in Figure 3(a) and the second printed image P2 shown in Figure 3(b). The outline of the first printed image P1 in Figure 3(a), the stroke width of the stroke in the lower left direction, and the stroke in the lower right direction of the second printed image P2 in Figure 3(b) are composed of 0.3 mm, and the stroke pitch is 0.6 mm.

[0103] [Example 1] Example 1 is an example in which the printed image P of the anti-counterfeiting printed material S shown in Figure 1 is visible in a bright purple color.

[0104] (Ink creation) For the first printed image P1, a red ink was prepared by blending 8.0% by mass of red colorant, 0.2% by mass of blue colorant, and 1.0% by mass of phthalocyanine pigment relative to the total ink volume. On the other hand, for the second printed image P2, a blue ink was prepared by blending 8.0% by mass of blue colorant, 0.2% by mass of yellow colorant, and 1.0% by mass of titanyl phthalocyanine pigment relative to the total ink volume.

[0105] <Visualization of the color tone of printed materials> Using the prepared ink, printing was performed using an offset printing press to obtain an anti-counterfeiting printed material S with the design "1000" printed in a bright purple as the composite color. The spectral reflectances of the first printed image P1 and the second printed image P2 are shown in Figure 6, and further details are as described in the above-mentioned embodiment.

[0106] <Determining the authenticity of printed materials> The obtained anti-counterfeiting printed material S was visually inspected in the visible wavelength range, visually inspected at a wavelength of 830 nm using an infrared visualization device, and visually inspected at a wavelength of 940 nm using an infrared visualization device. The results are shown in Figures 2, 4, and 5.

[0107] When the anti-counterfeiting printed material S according to Example 1 was viewed in the visible wavelength range, the "1000" design appeared as a bright purple color, as shown in Figure 2. Furthermore, when viewed at a wavelength of 830 nm using an infrared visualization device, the "1000" design appeared as a black color, as shown in Figure 4. Moreover, when viewed at a wavelength of 940 nm using an infrared visualization device, the "1000" design appeared as a black color, as shown in Figure 5. Since the "1000" viewed at a wavelength of 940 nm appears as approximately half the black density of the "1000" viewed at a wavelength of 830 nm, it is easy to distinguish between genuine and fake printed materials at each wavelength.

[0108] [Example 2] Example 2 is an example in which the printed image P of the anti-counterfeiting printed material S shown in Figure 1 is visible in a bright green color.

[0109] <Ink creation> For the first printed image P1, a blue ink was prepared by blending 8.0% by mass of a blue colorant and 1.0% by mass of a phthalocyanine-based pigment relative to the total ink volume. On the other hand, for the second printed image P2, a yellow ink was prepared by blending 8.0% by mass of a yellow colorant and 1.0% by mass of a titanyl phthalocyanine-based pigment relative to the total ink volume.

[0110] <Visualization of the color tone of printed materials> Using the prepared ink, printing was performed using an offset printing press to obtain an anti-counterfeiting printed material S with the design "1000" printed in a bright green as the composite color. The spectral reflectances of the first printed image P1 and the second printed image P2 are shown in Figure 7, and further details are as described in the embodiment.

[0111] <Determining the authenticity of printed materials> The resulting anti-counterfeiting printed material S is the same as in Example 1, so its description is omitted.

[0112] [Example 3] Example 3 is an example in which the printed image P of the anti-counterfeiting printed material S shown in Figure 1 is visible in a bright orange color.

[0113] <Ink creation> The ink for the first printed image P1 was prepared by blending 8.0% by mass of yellow colorant, 0.2% by mass of blue colorant, and 1.0% by mass of phthalocyanine pigment relative to the total ink volume to create a yellow ink. On the other hand, the ink for the second printed image P2 was prepared by blending 8.0% by mass of red colorant and 1.0% by mass of titanyl phthalocyanine pigment relative to the total ink volume to create a red ink.

[0114] <Visualization of the color tone of printed materials> Using the prepared ink, printing was performed using an offset printing press to obtain an anti-counterfeiting printed material S with the design "1000" printed in a bright green as the composite color. The spectral reflectances of the first printed image P1 and the second printed image P2 are shown in Figure 8, and further details are as described in the embodiment.

[0115] <Determining the authenticity of printed materials> The resulting anti-counterfeiting printed material S is the same as in Example 1, so its description is omitted.

[0116] [Comparative Example 1] Conventionally, carbon black has been widely used as a colorant that exhibits spectral reflectance absorption in the infrared region. Figure 9 shows the spectral reflectance measurements of printing inks of each color (blue, yellow, and red) prepared by mixing 15.0% by mass of each colorant (blue colorant, yellow colorant, and red colorant) with 1.0% by mass of carbon black. The printed image Pa shown in Figure 10 was then printed. The solid line B represents blue ink, the dotted line Y represents yellow ink, and the dashed line R represents red ink.

[0117] In the visible wavelength region shown in Figure 9, blue exhibits a reflectivity characteristic specific to yellow (approximately 43% reflectivity at a wavelength of 470 nm), yellow exhibits a reflectivity characteristic specific to yellow (approximately 39% reflectivity at a wavelength of 510 nm), and red exhibits a reflectivity characteristic specific to red (approximately 48% reflectivity at a wavelength of 620 nm). Therefore, it can be seen that all of these colors have low reflectivity and are dark hues.

[0118] Furthermore, in the infrared wavelength region shown in Figure 9, the 830nm-850nm wavelength range shows a reflectivity of approximately 57% for blue, 55% for yellow, and 58% for red. On the other hand, the 900nm-950nm wavelength range shows a reflectivity of approximately 60% for blue, 58% for yellow, and 61% for red. Therefore, it can be seen that the reflectivity is low and the hues are dark in all colors and wavelengths.

[0119] Therefore, the printed image Pa (labeled "1000" in Figure 11) visible in the wavelength range of 830 nm to 850 nm by the infrared visualization device shown in Figure 11, and the printed image Pa (labeled "1000" in Figure 12) visible in the wavelength range of 900 nm to 950 nm shown in Figure 12, both appear black. Consequently, it is possible to clearly distinguish them from the anti-counterfeiting printed material S according to the embodiment of the present invention.

[0120] [Comparative Example 2] Comparative Example 2 compares the inks with general printing inks. Figure 13 shows the spectral reflectance of printing inks of each color (blue, yellow, and red) prepared by adding 15.0% by mass of each colorant (blue colorant, yellow colorant, and red colorant) to the total ink volume, and then printing the print image Pb shown in Figure 14. The solid line B represents the blue ink, the dotted line Y represents the yellow ink, and the dashed line R represents the red ink.

[0121] In the visible wavelength region shown in Figure 13, blue exhibits a reflectivity characteristic specific to yellow (approximately 72% reflectivity at a wavelength of 470 nm), yellow exhibits a reflectivity characteristic specific to yellow (approximately 68% reflectivity at a wavelength of 510 nm), and red exhibits a reflectivity characteristic specific to red (approximately 81% reflectivity at a wavelength of 620 nm). Therefore, all colors exhibit high reflectivity and are bright hues.

[0122] Furthermore, in the infrared wavelength region shown in Figure 13, the wavelength range of 830nm to 850nm shows a reflectivity of approximately 94% for blue, 96% for yellow, and 96% for red. On the other hand, the wavelength range of 900nm to 950nm also shows a reflectivity of approximately 94% for blue, 96% for yellow, and 96% for red. Therefore, it can be seen that the reflectivity is high and the hues are bright in all colors and wavelengths.

[0123] Therefore, the printed image Pb visible in the wavelength range of 830 nm to 850 nm using the infrared visualization device shown in Figure 15 (labeled "1000" in Figure 15) and the printed image Pb visible in the wavelength range of 900 nm to 950 nm in Figure 16 (labeled "1000" in Figure 16) are both visible as white. Consequently, it is possible to clearly distinguish them from the anti-counterfeiting printed material S according to the embodiment of the present invention.

[0124] Therefore, the printed image P of the anti-counterfeiting printed material S of the present invention is easily distinguishable from printed materials using carbon black because the hue is bright and visible in the visible wavelength range. Furthermore, since the printed images visible in the wavelength range of 830nm to 850nm and the wavelength range of 900nm to 950nm are different, it is easy to determine authenticity, and the material has high resistance to counterfeiting.

[0125] Although the present invention has been described in detail above, various modifications can be made to the above configuration without departing from the scope of the invention. Therefore, all matters included in the above description or shown in the accompanying drawings should be construed as illustrative. [Explanation of Symbols]

[0126] S: Anti-counterfeiting printed matter B: Base material P: Printed image of the present invention P1: A first printed image that constitutes the printed image of the present invention. P2: A second printed image constituting the printed image of the present invention Pa: Printed image of Comparative Example 1 Pb: Printed image of Comparative Example 2

Claims

[Claim 1] An anti-counterfeiting printed material having a printed image consisting of a first printed image and a second printed image formed on at least a portion of the substrate, The first printed image and the second printed image are stacked, The colors of the first printed image and the second printed image are different. The maximum reflectance in the visible wavelength region of the first and second printed images is 40% or more. The first printed image is The average spectral reflectance in the wavelength ranges of 830 nm to 850 nm and 900 nm to 950 nm is 65% or less. The second printed image is, The average spectral reflectance in the wavelength range of 830 nm to 850 nm is 65% or less. The average spectral reflectance in the wavelength range of 900 nm to 950 nm is 90% or higher. An anti-counterfeiting printed material characterized in that the image density of the printed image visible in the wavelength range of 830 nm to 850 nm is different from that of the printed image visible in the wavelength range of 900 nm to 950 nm.

Images