JP5589162B2 - Copy protection ink and copy protection printed matter - Google Patents

Description

  The present invention relates to an anti-copying ink and an anti-copying printed matter that make it difficult to forge with a color copying machine or the like in valuable printed matter such as securities, certificates, admission tickets and various tickets.

  In recent years, with the development of digital devices such as scanners, printers, and color copiers, it has become possible to easily produce elaborate copies of precious printed matter. As one of the countermeasures, many methods using a metameric pair ink applying metamerism have been tried. The method of visual discrimination of precious printed matter using metameric pair ink is that the ink is judged to have the same color or different hue due to the type of light source to illuminate and the presence of a filter that transmits a specific wavelength. Is used.

  The above-mentioned metameric pair ink is recognized as a uniform color under a specific light source, but is two types of ink having different spectral reflectances at a specific wavelength with relatively low visibility in the visible light region. . The anti-counterfeiting technology and image printed matter formed using this ink have a metameric property so that a pattern can be recognized under a specific light source and a specific wavelength transmission filter (for example, Patent Document 1).

  Further, it is disclosed that a hue of a copy is made different by using a color material having a sharp peak in the vicinity of at least one of 400 nm, 500 nm, 600 nm, and 700 nm (see, for example, Patent Document 2). .

  In addition, an arbitrary colorant (first colorant) containing a yellow component having a spectral reflectance peak at least around 500 nm and a high spectral reflectance of 30% or more over the entire visible light region of the spectral reflectance. An ink containing a colorant (second colorant) having the colorant ratio of the first colorant and the second colorant in the range of 1: 1 to 1:20. An anti-counterfeiting ink and a forgery-preventing printed matter that are copied by changing the color due to removal or reduction of a yellow component that is difficult to be recognized by a photoreceptor are disclosed (for example, see Patent Document 3).

  Moreover, the spectral reflectance of the part which overlaps with at least one part of the area | region in which visible information is formed by the colored ink which contains the weight ratio of a pigment in the range of 1-15% among the base-material surfaces of printed matter. A forgery-preventing printed material that is 40% or more and is copied by changing the color of the yellow component, which is a color separation component obtained from colored ink, is disclosed (for example, see Patent Document 4).

JP 54-159004 A Japanese Patent Laid-Open No. 54-120009 Japanese Patent No. 2999354 Japanese Patent No. 3370753

  However, the metameric pair ink of Patent Document 1 recognizes a pattern by changing the reflectance near 650 nm, which is low in human visibility, in the visible light region. Even if it is visually recognized as a color, it is visually recognized as a different hue except under a specific light source, so that it is difficult to match the hues of the paired inks, and there remains a problem that the pattern can be visually recognized without using a filter. It was.

  Further, the metameric pair ink is a well-known technique that is generally known to give an anti-copying effect by using materials having different reflectances in the vicinity of the wavelength region of 650 nm. Since the same ink can be produced if it is understood, there is a problem that an elaborate counterfeit product may be produced.

  Further, as in Patent Document 2, the use of a color material having a sharp peak in the vicinity of at least one of 400 nm, 500 nm, 600 nm, and 700 nm only designates a region with low human visibility. However, since a specific method or the like is not disclosed, many problems remain until realization.

  In Patent Documents 3 and 4, by limiting to a light hue ink that has a high spectral reflectance in the visible light region and is difficult to be reproduced by a color copying machine, a yellow component with a high lightness is eliminated or reduced. Since setting is an essential condition, the overall color density is low. As a result, the color reproduction area is narrow, and the design is limited. Therefore, problems remain.

  The present invention has been considered in view of the foregoing points, and has a metameric property, has almost no hue change under a light source to be visually recognized, and a method of making the reflectance around a commonly used wavelength region ratio of 650 nm different. The present invention relates to an ink and printed matter having a high color density and an anti-copying effect that are not used and are not limited by design or the like.

  The anti-copying ink of the present invention is an anti-copying ink for preventing copying by a color copying machine, and has at least 18 to 35% by weight of a color pigment and 60 to 82% by weight of a varnish, and has a wavelength region. It has a top peak in the wavelength region of 480 nm to 500 nm in the range of 400 nm to 630 nm, the spectral reflectance of the top peak is 1.6 times or more of the spectral reflectance in the wavelength region of 440 nm, and the spectral reflectance at 540 nm. The anti-copying ink is characterized in that it has a spectral reflectance of 1.6 times or more of the rate and has a spectral reflectance of 440 nm and / or 540 nm of 25% or less.

  The color pigment used in the anti-copying ink of the present invention includes a blue material having a spectral reflectance of 60% or more in the wavelength region 490 nm, a yellow material and a green material, and a red material having a spectral reflectance of 20% or more in the wavelength region 490 nm, It is characterized by being an anti-copying ink using at least three or more selected from an orange material and a purple material.

  The anti-copying ink of the present invention is characterized in that it is an anti-copying ink containing 60 to 85% by weight of an oxidatively polymerizable or energy beam curable varnish.

  The anti-copying ink of the present invention is a non-copying ink containing functional materials such as infrared absorption characteristics, light emission characteristics, and magnetic characteristics.

  The anti-copying printed matter of the present invention is a non-copying printed matter having at least a first region printed with the above-described anti-copying ink on at least a part or all of the substrate.

  The copy-preventing printed matter of the present invention is a copy-preventing printed matter in which a second region is formed on a base material with a color material having the same color as the first color material.

  Since the anti-copying printed matter of the present invention is an anti-copying printed matter having an effect due to a difference in reflectance in a wavelength region different from that of a general metameric ink, there is an effect that it is extremely difficult to manufacture a counterfeit product.

  In addition, since the anti-copying ink and anti-copying printed matter of the present invention can reproduce a large number of hues and can produce an ink with a high color density, it is possible to produce a printed matter with high designability. There is an effect.

Diagram showing spectral reflectance in red and purple materials Diagram showing spectral reflectance in yellow material The figure which shows the spectral reflectance in the copy prevention printed matter of this invention The figure which shows the color difference of the copy prevention printed matter of this invention, and a copy matter The figure which shows the spectral reflectance of the metameric pair ink of Example 1 The figure which shows the copy prevention printed matter of Example 1. The figure which shows the copy of the copy prevention printed matter of Example 1 The figure which shows the color difference of the copy prevention printed matter of Example 1, and a copy matter The figure which shows the spectral reflectance in the copy prevention printed matter of Example 2. The figure which shows the spectral reflectance in the copy of Example 2. The figure which shows the copy prevention printed matter of Example 2. The figure which shows the copy of the copy prevention printed matter of Example 2

  DESCRIPTION OF EMBODIMENTS Embodiments for carrying out the present invention will be described with reference to the drawings. However, the present invention is not limited to the embodiments to be described below, and includes various other embodiments within the scope of the technical idea described in the claims.

  The copy protection printed matter of the present invention has a high color density and a sharp peak near the wavelength region of 490 nm by mixing pigments according to a certain standard without using special pigments, that is, sharp peaks. As a difference in reflectance from the vicinity of the base of the colorant, it is possible to produce a color material having a spectral reflectance of 1.6 times or more of the spectral reflectance at 440 nm and the spectral reflectance at 540 nm. When a printed material using the above-mentioned color material is copied using a color copying machine, the peak near 490 nm, which is low in human visibility, is also read with high sensitivity. Since it is reproduced, a copy-prevented printed matter that can prevent copying by a color copying machine is produced.

  The hue of the copy-prevented printed material of the present invention is not particularly limited. However, since the color of the copy produced by the color copying machine turns blue, it is preferable that the hue of the printed material is different from the color of the copied material. , Gray, green, purple and brown hues can be made.

  As for the pigment used in the color material of the present invention, in addition to the three primary colors of cyan, magenta and yellow, an intermediate color pigment such as orange, green or purple can also be used. It is desirable to select a pigment having a spectral reflectance of a material having a reflectance of a wavelength region of 490 nm that is greater than or equal to a certain value.

  Moreover, it does not specifically limit about the pigment used for a color material, A well-known pigment can be used. For example, dyed lake pigments such as acid dye-based lakes and basic dye-based lakes, insoluble azo pigments such as monoazo yellow, disazo yellow, β-naphthol, naphthol AS, pyrazolone and benzimidazolone, and condensed azo pigments. Azo pigments such as pigments and azo lake pigments, condensed polycyclic systems such as phthalocyanine, quinacridone, anthraquinone, perylene, perinone, indigo, dioxazine, quinophthalone, isoindolinone and diketopyrrolopyrrole A pigment or the like can be used.

  As for the blending ratio of each pigment, since it is necessary to be aware of subtractive color mixing that occurs when several types of pigments are mixed, it varies depending on the type of pigment selected, but a pigment having a wavelength region of 490 nm and a reflectance of 60% or more It is desirable to select Therefore, it is important to select red and purple pigments having a low reflectance near 490 nm. These pigments preferably have a reflectance at 490 nm of 20% or more, and when using a pigment of 20% or less, It is desirable that the above-described reflectance is 50% or less of the pigment having a reflectance of 20% or more.

  Regarding these conditions, each color pigment is made up of 30% by weight of primary color ink, and an IGT color developing machine from IGT / Testing Systems Japan is used to create a 1 μm thick color developed product. Hitachi High-Technologies Corporation Spectral reflectance was measured using a spectrophotometer “U-4100” manufactured by the company.

  As a pigment that can be used in the anti-copying ink of the present invention, the red pigment has a low reflectance in the vicinity of the wavelength region of 490 nm, and thus varies depending on the hue of the ink to be reproduced. A pigment such as red A, red B or red C having a reflectance of 20% or more is used in an addition amount of 10% or less. However, when the addition amount is small, for example, the addition amount corresponding to the ratio in which the reflectance in the wavelength region 490 nm is lower than that of the above-described monochromatic ink added with 10% of red A, that is, the spectrum of red A Since the reflectance is about 30%, when using red F having a spectral reflectance of about 15%, the red pigment of 20% or less can be used by setting the red A to 50% or less, which is 5% or less. Is possible.

  Further, even when a purple material containing a red component is used, it can be used as a material for the copy-preventing ink of the present invention by setting the amount to be the same as that of the red D to G described above.

  As shown in FIG. 2, the yellow pigment is selected from yellow pigments A, B, C and D having a reflectance of 40% or more in the wavelength region 490 nm. More preferably, it is preferable to select a yellow color containing a large amount of C components from 2G to 10G, and it is desirable to use yellow materials A and B. Since the same can be said for the yellow pigment as described above, other materials can be used by adjusting the addition amount. The blue and green pigments are not particularly limited because most of the pigments have a reflectance in the wavelength region near 490 nm of 60% or more.

  The entire pigment content needs to be a pigment content that does not reduce the reflectance in the wavelength region of 490 nm too much in consideration of the fact that the reflectance of the entire visible light region due to the subtractive color mixing is lowered. Therefore, although it varies depending on the pigment to be selected, it is necessary to make it 35% by weight or less, preferably 30% by weight or less in consideration of the concentration of the coloring material. However, since it is a feature of the present invention that the overall printing density is high, the blending ratio of the color pigment needs to be 18% by weight or more, and preferably the pigment content is 20% by weight or more. The amount of varnish added can be in the range of 60 wt% to 82 wt% in accordance with the amount of color pigment added, and in addition, a curable catalyst, a dispersant or various functional materials are added. can do.

  Next, an example of the blending ratio in the anti-copying ink of the present invention is shown below. In addition, the spectral reflectance of 490 nm in the green pigment, blue pigment, and yellow pigment used for the following mixing | blending is 60% or more. However, since the spectral reflectance of the purple pigment is 20% or less, the addition amount is 5% or less.

(Example of blending gray ink in the present invention)
Purple pigment 4.5% by weight
Green pigment 10.5% by weight
7.0% by weight of yellow pigment
Blue pigment 0.5% by weight
Varnish 62.5% by weight
Auxiliary agent 15.0% by weight

  FIG. 3 shows the spectral reflectance of the ink prepared by the above formulation. For the spectral reflectance shown in FIG. 3, a color developed product having a film thickness of 1 μm was prepared using the above ink using an IGT color developing machine manufactured by IGT Testing Systems Japan, and a spectrophotometer manufactured by Hitachi High-Technologies Corporation “ It is the result of measuring the spectral reflectance using “U-4100”, and is visually recognized as gray when visually observed under visible light.

  It can also be seen that the peak formed near 490 nm, which is weak to human visibility, is the highest peak in the wavelength range of 400 nm to 630 nm. As the actual spectral reflectance value, the spectral reflectance at 440 nm is 12.98, the spectral reflectance at 490 nm is 23.56, the spectral reflectance at 540 nm is 11.48, and the spectral reflectance at 490 nm is It is 1.8 times the spectral transmittance of 440 nm and 2.05 times the spectral reflectance of 540 nm. Furthermore, since the spectral reflectances at 440 nm and 540 nm, which are the characteristics of the present invention, are both 25% or less, it can be seen that the hue is high in density.

FIG. 4 shows the result of measuring the color difference between a copied product obtained by copying the above-described developed product with a color copying machine and the developed product. The color copiers used are as follows. Copy machine 1 C450 manufactured by Konica Minolta
Copier 2 C252 manufactured by Konica Minolta
Copier 3 Image Press C1 manufactured by Canon
Copy machine 4 Fuji Xerox Co., Ltd. Fuji Xerox Docucolor 4055F
Copier 5 Fuji Xerox Fuji Xerox Docucolor Copier 6 Sharp MX-4500FN
Make a copy using the above 6 types of copiers, and for the color difference, the spectral reflectance is the hue of the printed material (L *, a *, b *) using a GretagMacbeth spectrophotometer (SpectroEye Gretag). And the color difference (ΔE) was calculated.

  As for ΔE of the copied material, most of the copied material produced by the copying machine had a color change of ΔE6 or more, but the copied material obtained by the copying machine 3 had a color change of about ΔE3 and a low numerical value. However, as the blend of this ink does not use the black pigment necessary to easily reproduce gray, it is reproduced by blending the three primary colors in a balanced manner, and color changes are seen in the copy. However, the value of ΔE is low. Therefore, a visual evaluation confirmed significant color changes in all copies.

  As for hue, all the copies were shifted in the direction of bluish color and changed from gray to magenta. This is an ink having a sharp peak in the vicinity of 490 nm, which is low in human visual sensitivity, and what was visually recognized as gray without feeling the above peak is markedly read by the copier. In order to reproduce the hue of the color-extended product, the hue of the copy changes.

  In the above-described embodiment, the color material is described as ink. However, when printing is performed using ink, the substrate to be printed is not particularly limited, and can be printed on paper, plastic, film, and metal plate. In addition, the ink used for the copy-preventing printed material of the present invention is not particularly limited to the printing method on the base material such as paper, and the offset printing method, the gravure printing method, the screen printing method, the flexographic printing method, the intaglio printing method. A known printing method such as can be used.

  Hereinafter, examples of the present invention will be described with reference to the drawings. However, the embodiments of the present invention are not limited to the following examples, and are within the scope of the technical idea described in the claims. If present, various other embodiments are included.

  Examples of the copy-prevented printed material of the present invention will be described. First, dark green ink was prepared as the first ink used for the copy-preventing printed material. The composition of the first ink is shown below. The spectral reflectance at 490 nm of the yellow pigment and blue pigment used in this ink is 60% or more. Moreover, about 20% or more of the red pigment was used, but the amount added was 5% or less in order to reproduce dark green.

(Formulation of the first ink in Example 1)
Red pigment 4.0%
Yellow pigment 13.0%
Blue pigment 3.0%
Varnish 70.0%
Auxiliary 10.0%

  In addition, as a paired ink with the above-described dark green metameric ink, a second ink using a common three primary color pigment that is visible as a uniform color under visible light but does not have a sharp peak in the wavelength region of 490 nm. An ink was prepared. The formulation of the second ink is shown below.

(Composition of the second ink in Example 1)
Red pigment 3.5%
Yellow pigment 10.5%
Blue pigment 3.0%
Varnish 70.0%
Auxiliary 13.0%

  The spectral reflectance in the above-mentioned pair ink will be described with reference to FIG. The pair inks in FIG. 5 have different reflectances in the vicinity of a wavelength region of 490 nm where the visibility is low, but when viewed with the naked eye, they are visually recognized as dark green. However, when copying with a color copying machine, the spectral reflectance in the visible light region is remarkably reproduced, so the peak in the wavelength region of 490 nm in the first ink is read, and the reflectance around 450 nm is high in line with the peak at 490 nm. Because it is reproduced, the copy turns blue. The spectral reflectance of this ink is characterized by having a top peak in the vicinity of 490 nm in the range of 400 nm to 630 nm, and the spectral reflectance at 490 nm is 2.4 times the spectral reflectance at 440 nm and the spectral reflectance at 540 nm. The value is 1.7 times the transmittance.

  On the other hand, for the second ink, since there is no conspicuous peak or the like in an area where human visibility is low, the reproduced color remains dark green because it is reproduced as a hue substantially equivalent to the hue visually recognized by the naked eye. It is reproduced.

  The anti-copying printed matter produced by offset printing using the above-mentioned metameric pair ink will be described with reference to FIGS. In the copy prevention printed matter of FIG. 6, the first print area is printed with the first ink, and the second print area is printed with the second ink. When the copy-prevented printed material is visually recognized with the naked eye, the first print area and the second print area are printed with the same color ink, so that the printed image is visually recognized as a dark green solid printed material.

  When this printed material is copied by a color copying machine, the first printed area is printed with the first ink as shown in FIG. 7, so that the copied material turns blue and a star-shaped pattern appears. On the other hand, since the second printing area is printed with the second ink, it is reproduced with the same hue as that of the copy-prevented printed matter, and therefore is visually recognized as a star-shaped background pattern.

  Further, FIG. 8 shows data obtained by copying the developed color product produced with the first ink using the above-described six types of copying machines and measuring ΔE. As shown by ΔE in FIG. 8, it can be seen that all the copiers show a high color difference. The gray ink in the above-described embodiment has a low color difference of the copy by the copying machine 3, but the dark green first ink shows a high color difference. It can be seen that the color that can be reproduced differs depending on the type.

  Next, a printed matter using three types of ink that is visually recognized as a uniform color under visible light and that changes colors to red, green, and blue during copying will be described with reference to FIGS. 9, 10, and 11. . The blending in the above three types of inks is as follows.

(Formulation of ink that changes color to red in Example 2)
Purple pigment 4.5%
Red pigment 0.1%
Yellow pigment 18.0%
Varnish 67.0%
Auxiliary 10.4%

(Composition of ink that changes color to green in Example 2)
Green pigment 11.0%
Red pigment 7.0%
Yellow pigment 2.0%
Varnish 70.0%
Auxiliary 10.0%

(Composition of ink that changes color to blue in Example 3)
Green pigment 4.5%
Red pigment 6.0%
Yellow pigment 10.0%
Blue pigment 1.0%
Varnish 68.5%
Auxiliary 10.0%

  The spectral reflectance in the above three types of ink will be described with reference to FIG. FIG. 9 summarizes the spectral reflectances of the three types of inks as a single graph, and FIG. 10 shows the spectral reflectances of the copy of the three types of inks. The copy was prepared using Konica Minolta C450, and the spectral reflectance was evaluated using a spectrophotometer “U-4100” manufactured by Hitachi High-Technologies Corporation.

  As can be seen from the spectral reflectance shown in FIG. 9, the spectral reflectance of the three types of inks is such that the red (7) ink has a significantly higher spectral reflectance near 650 nm. Ink (6) that reproduces reddish color and changes color to green has a sharp peak near 580 nm, so the copying machine reproduces greenish color and changes color to blue (5 ) Has a sharp peak in the vicinity of 490 nm, so that the copying machine reproduces a bluish color. Regarding the characteristics of the reflectance of the ink that changes to blue, it has a top peak in the vicinity of 490 nm within the range of 400 nm to 600 nm, and the spectral reflectance at 490 nm is 2.5 times the spectral reflectance at 440 nm. Yes, the value is 1.7 times the spectral transmittance at 540 nm.

  The selection of pigments and blending amounts for producing these inks includes black, blue, or green, which has a low spectral reflectance of 650 nm in order to increase the spectral reflectance of 650 nm or more in the case of an ink that changes color to red. Without using a pigment, a purple pigment having a bluish component is used, and the brown color is reproduced by supplementing the bluish component for reproducing the brown color.

  Moreover, since the ink which changes color to green has a sharp peak at 580 nm, the brown color is reproduced by supplementing the blue component with a large amount of green pigment. In addition, since the ink that changes to blue has a sharp peak in the vicinity of 490 nm, a lot of 10G yellow pigment having a spectral reflectance of about 90% on the shorter wavelength side than 490 nm is used, and the spectral reflectance becomes 490 nm. In order to suppress the influence of the above, it is characteristic that brown is reproduced by using a red pigment having a spectral reflectance near 490 nm of 20% or more.

  The printed matter produced using these three types of ink will be described with reference to FIGS. FIG. 11 shows a state in which the printed material is visually recognized under visible light. Since ink that is visually recognized as a uniform color under visible light is used, the printed material is visually recognized as a single color background pattern. However, when this printed matter is copied, each ink changes color to red, green, and blue. As shown in FIG. 12, all three types of ink change to different hues. Appears.

  It is also possible to reproduce a copy having a full color gradation by RGB assuming the hue after copying using these three types of ink (not shown).

DESCRIPTION OF SYMBOLS 1 Copy prevention printed matter of Example 1 2 Copy of copy prevention printed matter of Example 1 3 Spectral reflectance curve in 1st ink of Example 1 4 Spectral reflectance curve in 2nd ink of Example 1 5 Example Ink that changes to blue in 2 6 Ink that changes to green in Example 7 7 Ink that changes to red in Example 8 8 Copy prevention printed matter of Example 2 9 Copy of copy prevention printed matter of Example 2 10 Example 2 Area printed with ink that changes color to blue in Example 11 Area printed with ink that changes color to green in Example 12 Area printed with ink that changes to red color in Example 2 A First printing area in Example 1 B Implementation Second print area in example 1

Claims (6)

Anti-copying ink to prevent duplication by color copiers,
The anti-copying ink has at least 18% to 35% by weight of color pigment and 60% to 82% by weight of varnish;
The colored pigment is selected from a blue material, a yellow material and a green material having a spectral reflectance of 60% or more in a wavelength region of 490 nm, and a red material, an orange material and a purple material having a spectral reflectance of 20% or more in a wavelength region of 490 nm. Including at least three,
The spectral reflectance of the anti-copying ink has a top peak in the wavelength region of 400 nm to 630 nm in the wavelength region of 480 nm to 500 nm, and the spectral reflectance of the top peak is the spectral reflectance in the wavelength region of 440 nm. Anti-copying ink characterized by having a spectral reflectance of 1.6 times or more and 1.6 times or more of the spectral reflectance at 540 nm   2. The anti-copying ink according to claim 1, wherein the anti-copying ink has a spectral reflectance of 25% or less in a wavelength region of 440 nm and / or 540 nm. The anti-copying ink according to claim 1 or 2 , wherein the varnish is an oxidatively polymerizable or energy ray curable varnish. The anti-copying ink according to any one of claims 1 to 3 , wherein the anti-copying ink contains at least one functional material selected from infrared absorption characteristics, light emission characteristics, and magnetic characteristics. An anti-copying printed matter comprising at least a first region printed with the anti-copying ink according to any one of claims 1 to 4 on at least a part or all of a substrate. 6. The anti-copying printed matter according to claim 5 , wherein the anti-copying printed matter has a second region formed of ink of the same color as the anti-copying ink.

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