JP7148927B2 - anti-counterfeit printed matter - Google Patents

Description

In the field of security printed matter such as banknotes, passports, negotiable securities, identification cards, cards, transit tickets, etc., which require an anti-counterfeiting effect, the present invention can be used to obtain different images depending on the angle of incident light. It is related to anti-counterfeiting printed matter that changes to

With the recent development of digital devices such as scanners, printers, and color copiers, it has become possible to easily produce elaborate copies of valuable printed materials. As one of anti-counterfeiting techniques for preventing such duplication and counterfeiting, there have been many techniques in which an optical security element such as a hologram whose image changes depending on the viewing angle of printed matter is attached.

However, unlike conventional anti-counterfeiting technology that uses printing with ink, holograms are formed using complex manufacturing processes and special materials. It is time-consuming and expensive. For this reason, special light-reflecting powders such as metal inks, interference mica, oxide flake mica, aluminum flakes, and optically variable flakes are blended into inks and paints. There are anti-counterfeiting printed matter that can be formed by a general printing method, which realizes an image change similar to that of a hologram by using a halftone dot configuration.

The present applicant has found that information recognized by the human eye at a specific site in the printed matter at a specific viewing angle, while using common and relatively inexpensive materials and simple printing means, We have already applied for inventions related to anti-counterfeiting information carriers that change to completely different information by changing reference).

The techniques of Patent Literatures 1 and 2 are techniques for forming anti-counterfeit printed matter by superimposing an image of transparent ink on an image of glittering ink. This technology does not require color adjustment for images with glitter ink, and does not allow latent images to be visualized under diffusely reflected light. However, since invisible transparent ink is used, there is a problem that it is difficult to control print quality during manufacturing. Specifically, even if there is a printing problem where the ink is not printed at all, it is difficult for workers to quickly detect quality abnormalities because transparent ink is used that is invisible to the naked eye. was there.

As a countermeasure for this, we use a transparent luminescent ink, which is a mixture of transparent ink and UV-excited luminescent pigment, and irradiate UV rays during printing to determine whether the transparent ink has been printed without any problems. was common. However, if such countermeasures are used, quality control at the time of manufacturing becomes possible, but on the other hand, the configuration of the latent image can be easily grasped by looking at the luminescence image that appears when the product is irradiated with ultraviolet light. could give clues to the structure of anti-counterfeiting technology, and there was a problem with respect to resistance to counterfeiting.

On the other hand, the technique of Patent Literature 3 is a technique that realizes an image change effect by forming two images using a glitter material and a colored ink having the same color as the glitter material as a pair of inks. Further, in one form of the technique of Patent Document 4, a glittering ink and a colored ink having a lighter color (lower density) than the glittering ink are used as a pair of inks, and an image is formed under diffusely reflected light and specularly reflected light. It is a technology that realizes the change effect. The technique of Patent Document 5 is a technique that achieves an image change effect under diffusely reflected light and specularly reflected light by using a pair of bright ink and ink having the same dark hue as the bright ink. As described above, the techniques disclosed in Patent Literatures 3 to 5 enable the printed pattern to be visually recognized by using colored ink, and can solve the above-described problem.

Japanese Patent No. 4604209 Japanese Patent No. 5358819 Japanese Patent No. 5245102 Japanese Patent No. 5360725 JP 2017-100331 A

Anti-counterfeiting technology applied to security printed matter is not used by itself in reality, but is integrated with various design elements such as background patterns, colored patterns, portraits and letters to form part of the printed matter. Of course, using a large number of inks solely to create an anti-counterfeit technique limits the number of inks that can be used for other design elements. For example, the techniques of Patent Documents 1 and 2 use glitter ink and transparent ink, so printing is performed with a limited number of printing press units, such as a four-color printing press (four-cylinder printing press). In some cases, by occupying two units, the amount of ink allocated to designs other than anti-counterfeit technology is reduced, and there are restrictions on the color design of the entire printed matter.

Further, the techniques of Patent Documents 3 to 5 are technologies that can be formed by using two colored inks as a pair of inks, have high latent image hiding properties, and do not require the use of transparent inks. must have at least the same hue. For this reason, when forming the anti-counterfeiting technology from Patent Document 3 to Patent Document 5 with a printing machine with a limited number of printing units, it is necessary to use glitter ink of the same color as the colored ink used for other design elements. In addition, there is a constraint on the color design of the printed image that produces an image change effect under diffusely reflected light and under specularly reflected light.

An object of the present invention is to solve the above-mentioned problems, and it has the effect of changing the image under diffusely reflected light and under specularly reflected light by forming a pair of inks of chromatic glitter ink and achromatic ink. To provide an anti-counterfeiting printed matter which is a printed matter and can be produced without being subject to color restrictions.

The anti-counterfeiting printed matter of the present invention has a chromatic printed image with partially different densities on at least a part of the base material, and when observed under diffusely reflected light, a visible image due to the shades of the printed image is visually recognized, and the printed image is correct. A counterfeit-preventive printed matter in which a latent image is visible when observed under reflected light, wherein the printed image includes a first image formed with a chromatic ink having a luster and a second image formed with an achromatic ink. Two images are superimposed, and the second image expresses a latent image by partially varying the density in the range of 0.5 or less of the maximum black component density of the image formed with achromatic ink. The first image has a density obtained by subtracting the density of the second image from the density of the printed image under diffusely reflected light, and the density is partially different.

Further, in the anti-counterfeiting printed material of the present invention, the difference between the maximum area ratio and the minimum area ratio of the first image is 70% or less, and the minimum area ratio of the first image is 20% or more. do.

In addition, the anti-counterfeiting printed matter of the present invention has a printed image in chromatic colors and partially different densities on at least a part of the base material, and when observed under diffusely reflected light, a visible image due to the shading of the printed image is visually recognized. , a counterfeit-preventive printed matter in which a latent image is visible when observed under specularly reflected light, the printed image is formed of achromatic ink, and the latent image is revealed by partially different densities; and a chromatic image having a density obtained by subtracting the density of the second image from the density of the printed image under diffusely reflected light and superimposed on the second image, wherein the chromatic image is , a first image formed with chromatic ink having glitter and partially different in density, and formed with ink of the same hue as the ink forming the first image and/or achromatic ink, and a partial characterized by a third image that reveals a latent image with a substantially different density.

The two images constituting the anti-counterfeiting printed matter of the present invention can be formed using chromatic ink and the other using achromatic ink. There is no need to use two inks with the same hue as in the prior art, and the degree of freedom in ink selection is high. In particular, compared with the technique of Patent Document 5, the options for the colors of chromatic inks (bright inks) are remarkably wide, and therefore the degree of freedom in designing the colors of printed images is high.

In addition, since the anti-counterfeiting printed matter of the present invention does not use transparent ink unlike the prior art described in Patent Documents 2 and 3, it is not necessary to manage the latent image by emitting light, and it is formed with achromatic ink. The quality of the resulting image can be visually controlled. Therefore, after the two images are superimposed to form a finished product as a printed image, it is difficult to see through the structure, and the forgery resistance is high.

The achromatic ink used in the present invention is basically light gray to dark gray, and can be diverted from the black ink used in ordinary process color printed matter. Therefore, it is not necessary to prepare two pairs of inks exclusively for forming this technology, and what is necessary to prepare only for forming the anti-counterfeiting technology is 1 Color only. Thus, the technique can be configured with one cylinder in the print unit, and the other print cylinders can be infused with different color inks to form design elements other than anti-counterfeiting techniques. As a result, it is possible to increase the degree of freedom in color design for design elements other than anti-counterfeit technology in printed matter.

1 shows anti-counterfeit printed matter in the present invention. 1 shows an overview of the configuration of a forgery-preventive printed matter according to the present invention; 1 shows an overview of the configuration of a first image in the present invention; FIG. 4 shows a schematic diagram of a method for calculating the density of the first image in the present invention; 1 shows the layer structure of the anti-counterfeit printed matter in the present invention; 3 shows the effect of anti-counterfeiting printed matter in the present invention. 1 shows an overview of the configuration of a forgery-preventive printed matter according to the present invention; 1 shows an overview of the configuration of a forgery-preventive printed matter according to the present invention; 1 shows an overview of the configuration of a forgery-preventive printed matter according to the present 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.

(First embodiment)
First, an embodiment of the present invention will be described with reference to FIGS. 1 to 6. FIG. FIG. 1 shows an anti-counterfeit printed matter (1) according to the present invention. An anti-counterfeit printed matter (1) has a chromatic printed image (3) on a substrate (2). FIG. 1 shows an example in which the printed image (3) is formed on a part of the base material (2), but the printed image (3) may be formed on the entire base material (2). The printed image (3) represents a visible image under diffusely reflected light. Note that the visible image in the first embodiment refers to the Chinese character "sakura" and the circle surrounding it. That is, in the present invention, the entire pattern represented by the printed image (3) under diffusely reflected light is a visible image. Note that, in the present invention, the image represented by the visible image is not limited to the characters "cherry blossom", but may be other characters, symbols, other patterns, or various images such as people and landscapes. It may be a gradation image. Also, in the present embodiment, an ellipse is arranged around the outer periphery of the printed image (3), but this is an accessory for making it easier to grasp the positional relationship of each image in the description of this specification. , is irrelevant to its function.

The printed image (3) is formed by superimposing the first image (4) and the second image (5) shown in FIG. The first image (4) is formed with a chromatic ink having glitter (hereinafter referred to as "chromatic ink"), and the second image (5) is formed with achromatic normal ink (hereinafter referred to as "achromatic ink"). (referred to as "colored ink"). The second image (5) alone represents a latent image (in the first embodiment, a “cherry blossom petal” design), while the first image (4) alone represents a visible image. Instead, the visible image is represented by overlapping with the second image (5).

In a first embodiment, the visible image consists of representing a simple binary image. In this case, as shown in FIG. 3, the first image (4) consists of an information portion (4A) and a background portion (4B). The information part (4A) constitutes the character of the kanji "cherry blossom" represented by the printed image (3) under diffusely reflected light by its outline, and the information part (4A) further includes a second image to be described later. It consists of a first information section (4A-1) superimposed on the latent image section (5A) of (5) and a second information section (4A-2) other than that. One background portion (4B) is an image obtained by removing the information portion (4A) from the first image (4), and the background portion (4B) is the latent image portion ( 5A), and a second background portion (4B-2).

The second image (5), on the other hand, consists of a latent image portion (5A) and a background portion (5B), as shown in FIG. Constructs a latent image. The latent image portion (5A) constitutes a "cherry blossom petal" pattern by its outline, and the background portion (5B) has the same size as the print image (3) and is the area of the print image (3). The region excluding the region of the latent image portion (5A) is in contact with the latent image portion (5A). One of the latent image portion (5A) and the background portion (5B) is dark and the other is light, so that the latent image can be expressed in a relationship of different shades. If the latent image portion (5A) is dark, the image will be positive, and if the background portion (5B) is dark, the image will be negative. Also, either the latent image portion (5A) or the background portion (5B) must be formed with an arbitrary area ratio greater than 0, but the other may have an area ratio of 0.

In the following description of the present embodiment, a configuration in which the area ratio of the latent image portion (5A) is higher than that of the background portion (5B) and the area ratio of the background portion (5B) is zero will be described. In the present invention, the entire pattern represented by the printed image (3) under specularly reflected light is the latent image. The second image (5) is formed with a normal achromatic ink containing black or gray pigments or dyes as coloring materials without containing luster pigments as coloring materials in the ink.

When a visible image is represented by a binary image as in the first embodiment, the information portion (4A) and the background portion (4B) in the first image (4) must have predetermined densities, and , must have a density difference from each other. This is an essential condition for representing visible images by shading. Details of the predetermined densities of the information portion (4A) and the background portion (4B) in the first image (4) will be described later. It is formed with an area ratio of 20% or more, and the two regions are provided with the color of chromatic ink. The information portion (4A) and the background portion (4B) of the first image (4) must have a predetermined density. ) may have a reflection density of 0, that is, there may be a region not formed by achromatic ink.

In addition, the respective regions of the first image (4), the first information portion (4A-1), the second information portion (4A-2), the first background portion (4B-1), the second The background portion (4B-2) of has different shades. The gradation configuration of each area of the first image (4) will be described. The density of the first image (4) is the density obtained by subtracting the density of the second image (5) overlapping the same position from the density of the visible image represented by the printed image (3) under diffusely reflected light. be. A specific description will be given with reference to FIG.

In the anti-counterfeit printed matter (1) of the present invention, the first image (4) of the printed image (3) is composed of chromatic inks, and the second image (5) is composed of achromatic inks. The calculation of the density of the first image (4) is basically based on the reflection density Db of the black component. Assuming that the printed image (3) is formed in dark brown, as shown in FIG. 0, the other area of the printed image (3) has a density of 1.3 in reflection density Db of the black component, and the latent image portion (5A) of the second image (5) is black. If the component reflection density Db has a density of 0.2, the density of each area of the first image (4) is reduced from the density of the printed image (3) to the density of each area of the second image (5) It is a relationship that reduces .

In the printed image (3) having the configuration shown in FIG. The reflection density Db0.8 is obtained by subtracting the reflection density Db0.2 of the black component of the latent image portion (5A) of the image (5). , the black component reflection density Db remains at 1.0. Further, the first background portion (4B-1) is obtained from the reflection density Db1.3 of the black components other than the “cherry blossom” of the printed image (3) to the black of the latent image portion (5B) of the second image (5). The reflection density Db1.1 is obtained by subtracting the reflection density Db0.2 of the component, and the second background portion (4B-2) has a reflection density Db of 1 for the black component in the area other than the "cherry blossom" of the print image (3). .3. In addition, when the reflection density Db of the black component of the second image (5) is higher than that of the black component of the first image (4), the configuration of the second embodiment described later can be used.

In the first embodiment of the present invention, when the reflection density Db of the black component of the second image (5) exceeds a certain value, the concealability of the latent image is impaired. ) should not exceed 0.5. This is essential in constructing the forgery-preventive printed matter (1) of the first embodiment of the present invention. In order to provide a structure with a high hiding effect for the latent image represented by the second image (5), the maximum reflection density Db of the black component in the second image (5) is desirably 0.3 or less. Preferably. In order to obtain the contrast of the latent image under specularly reflected light, the reflection density Db of the latent image portion (5A) of the second image (5) is preferably 0.1 or more.

Once the reflection density Db of the black component is determined, the design of the first image (4) is completed by converting it into an area ratio based on the level of the reflection density. For example, if the area ratio of the second background portion (4B-2) with a reflection density of 1.3 is assumed to be 85%, the area ratio of the first information portion (4A-1) with a reflection density of 0.8 is The ratio of the reflection density is about 52%, the area ratio of the second information part (4A-2) with a reflection density of 1.0 is about 65%, and the first background part (4B-2) with a reflection density of 1.1 is about 65%. The area ratio of 1) should be about 72%. At this time, the difference between the maximum area ratio and the minimum area ratio in the first image (4) should be 60% or less, and the minimum area ratio in the first image (4) should be 20% or more. It is desirable to design Although it depends on the density of the chromatic ink, basically the difference between the maximum area ratio and the minimum area ratio of the first image (4) exceeds 70%, or the minimum area in the first image (4) If the ratio is less than 20%, the concealability of the latent image is greatly reduced, which may cause the problem of the latent image becoming visible under diffusely reflected light. If such a problem occurs, it is necessary to use the configuration of the second embodiment, which will be described later.

In the present invention, the density of the first image (4) is designed based only on the reflection density Db of the black component. In addition to the reflection density Db of the black component, the reflection density Dc of the blue component, the reflection density Dm of the red component, and the reflection density Dy of the yellow component each have an arbitrary value. Therefore, when the first image (4) and the second image (5) overlap to form the printed image (3), the blue, red, and yellow components other than the black component are out of balance, and the color tone is partially large. difference may occur and the latent image may become visible. In order to prevent this problem, first, it is desirable to set the difference between the maximum area ratio and the minimum area ratio in the first image (4) to 70% or less and the minimum area ratio to 20% or more. This is a device for minimizing the difference in hue between the chromatic ink and the achromatic ink.

Generally, in the achromatic ink, the reflection density Db of the black component, the reflection density Dc of the blue component, the reflection density Dm of the red component, and the reflection density Dy of the yellow component exist in a well-balanced manner with substantially equal values. Color inks have arbitrary values of reflection density Db of black component, reflection density Dc of blue component, reflection density Dm of red component, and reflection density Dy of yellow component. Therefore, if chromatic ink and achromatic ink are simply arranged side by side, there is no way to eliminate the difference in hue caused by the difference in reflection density balance of each color component. However, in the present invention, two inks are superimposed, and the difference in hue between the two inks is converted into a pseudo density difference, so that the first information part (4A-1) and the second information When the second image (5) is laminated on the part (4A-2) and when the second image (5) is laminated on the first background part (4B-1) and the second background part (4B-2) It is possible to match the colors when laminated.

First, the achromatic ink that constitutes the second image (5) cannot express the specific hue of chromatic ink, but it expresses simple shading (difference in density) or light and shade (difference in light and shade). You can. Therefore, the area ratio of the chromatic inks in the first image (4) is kept at a certain level or more (minimum area ratio of 20% or more), and the chromatic inks are always placed in all areas of the first image (4). , there is no hue difference in the first image (4). At this time, since the first image (4) contains only a simple density difference due to the chromatic ink, the density difference in the first image (4) is treated as a pair of achromatic color inks. It becomes possible to supplement with ink. Of course, the densities of the chromatic ink and the achromatic ink are not exactly the same because the reflection density balance of each color component is different, but unless the density difference in the first image (4) is large ( The difference between the maximum area ratio and the minimum area ratio is 70% or less), the area whose density is complemented with achromatic ink, for example, the color of the first information part (4A-1) and the second information part (4A-2) It becomes difficult to recognize the difference in ingredients at first glance.

Since achromatic colors basically maintain the basic color components of black, blue, red, and yellow in a well-balanced manner, they can be said to be the most suitable colors for complementing colors of all hues. There are limits to the densities that inks can replace and complement chromatic inks. Depending on the relationship between the two colors of the chromatic ink and the achromatic ink, the effect of compensating for the density difference of the first image (4) with the achromatic ink is lost when the density exceeds a certain level. This is the reason why the reflection density of the black component in the second image (5) composed of achromatic ink is set to 0.5 or less.

As described above, in the first embodiment of the present invention, the latent image can be hidden in the visible image in spite of using chromatic ink and achromatic ink having different hues. This is because the inks are superimposed, the first image (4) has an appropriate area ratio limit, and the density of the achromatic ink in the second image (5) is limited. It is difficult to obtain the effect of the present invention.

In the present invention, the method of complementing the density difference in the first image (4) formed with chromatic ink with the shade of the second image (5) formed with achromatic ink is, in other words, It can also be said that this is a method of camouflaging the latent image by adjusting the brightness of the printed image (3) (visible image). As a matter of course, when there is a large color difference between chromatic and achromatic colors, it is possible that the difference in hue cannot be completely covered and the latent image cannot be made completely invisible. A countermeasure for that case will be described in a second embodiment.

Next, specific colors and optical characteristics of the chromatic inks forming the first image (4) and the achromatic inks forming the second image (5) will be described. First, the chromatic inks forming the first image (4) will be described.

A chromatic ink must have a predetermined density that is visible under diffusely reflected light. The color of the chromatic ink may be the same as that of the substrate (2) or may be different from that of the substrate (2). It is preferable because the visibility of a visible image under reflected light is high. Further, the reflection density Db of the black component of the first image (4) formed with chromatic ink is higher than the reflection density Db of the black component of the second image (5) formed with achromatic ink. It is desirable for the second image (5) to have better hiding power. However, even if this condition is not satisfied, the concealing effect of the latent image can be maintained by using the configuration described in the second embodiment. In the present invention, since there is no constraint on the hue between paired inks, the options for color design of the printed image (3) under diffusely reflected light are greatly expanded. For example, when the second image (5) is achromatic, in Patent Document 5, the color of the printed image (3) had to be achromatic due to restrictions on hue design. Any chromatic color such as blue, red, yellow, etc. can be used for the printed image (3).

Regarding the optical properties of chromatic inks, there are so-called light-dark flip-flop properties, in which light is strongly reflected under specular reflection light and the color changes to a faint color, or the so-called light-dark flip-flop property, in which light is strongly reflected under specular reflection light and the hue changes, is called It must have at least one characteristic of color flip-flop properties. In the present specification, having at least one characteristic of a bright-and-dark flip-flop property or a color flip-flop property is defined as "having luster". In any case, it is necessary for chromatic inks to differ greatly in the color under diffusely reflected light and the color under specularly reflected light. becomes higher.

Commercially available chromatic metallic inks such as bluish-golden and reddish-golden may be used as the chromatic ink having a light-and-dark flip-flop property. Coloring pigments such as red, blue, and yellow may be blended into the achromatic silver ink to make it chromatic. Pigments that can be used in these inks include aluminum powder, copper powder, zinc powder, tin powder, brass powder, iron phosphide, and the like.

On the other hand, as the chromatic ink having a color flip-flop property, a pearl ink having a body color called a dichroic pearl ink may be used, a commercially available pearl ink may be colored and used, or a transparent ink may be used. A colored pearl ink or the like may be prepared and used by blending a pearl pigment and a coloring pigment. In addition, as a luster material exhibiting color flip-flop properties, there are general pearl pigments such as iridescent pearl pigments and scaly pigments, glass flake pigments, cholesteric liquid crystal pigments, and the like. By utilizing these, it is possible to obtain a chromatic ink having luster. The above is the description of the chromatic ink.

Next, the achromatic ink used for the second image (5) will be described. Gray or black ink may be used as the achromatic ink used in the present invention. However, any of them must have at least a visible density when the second image (5) is formed. As for the color, it is most desirable to use black ink in order to increase the degree of freedom in design. One of the features of the present invention is that the achromatic ink, which is one of the paired inks, is used in common with the ink that constitutes the design elements other than the anti-counterfeiting technology, such as background patterns, colored patterns, and characters, so that the anti-counterfeiting technology can be improved. There is no need to use two colors of dedicated ink just for formation. A configuration in which characters and background patterns other than the printed image (3) are formed using solid black ink, and the area for forming the second image (5) of the present invention is slightly reduced and used as gray, Most efficient.

Further, it is desirable that the optical properties of the achromatic ink are matte. It is desirable that the color under diffusely reflected light and the color under specularly reflected light do not change significantly without strongly reflecting light under specularly reflected light. This is because the greater the difference between the color of the chromatic ink under specularly reflected light and the color of the achromatic ink under specularly reflected light, the higher the visibility of the latent image appearing under specularly reflected light. The above is the description of the achromatic ink.

In addition, functional materials such as luminous pigments such as fluorescent pigments, phosphorescent pigments and luminous pigments, IR absorbing pigments, photochromic pigments, thermochromic materials and thermochromic materials may be added to the chromatic and achromatic inks.

Next, the stacking order of the first image (4) and the second image (5) will be described with reference to FIG. The anti-counterfeit printed matter (1) of the present invention is formed by printing a first image (4) on a substrate (2) and then superimposing a second image (5) thereon, as shown in FIG. Considering the concealability of the latent image, the lamination order in which the first image (4) is superimposed on the second image (5) is preferable. However, in the case of the layer structure shown in FIG. 5, the incident light that enters the first image (4) is blocked by the achromatic ink superimposed thereon, and the visibility of the latent image under specularly reflected light is high. demonstrated. For this reason, considering the visibility of the latent image, it is desirable that the stacking order is such that the second image (5) is superimposed on the first image (4).

The effects of the anti-counterfeiting printed matter (1) produced with the above configuration will be described with reference to FIG. When the positional relationship between the light source (6), the anti-counterfeiting printed matter (1), and the observer (7) is observed at an observation angle in which diffusely reflected light is dominant as shown in FIG. A visible image of the kanji characters for "cherry blossom" is visually recognized in the image. Under the diffusely reflected light, the cherry blossom petal mark, which is the latent image, cannot be visually recognized.

On the other hand, when the anti-counterfeiting printed matter (1) is observed at an observation angle in which the specularly reflected light is dominant as shown in FIG. completely disappears, and the cherry blossom petal mark, which is the latent image, is visually recognized.

The basic principle of the two-image change of the present invention is as follows. At the observation angle shown in FIG. 6(a) where the diffusely reflected light is dominant, the visible image is visually recognized due to the difference in density in the printed image (3). A latent image in a visible image is invisible, or becomes unrecognizable as it blends into the shading of the visible image. On the other hand, at an observation angle where regular reflected light is dominant, as shown in FIG. By reflecting and changing light, the visual density difference in the area other than the second image (5) becomes relatively small, and the gradation (shading) is compressed, making the first image (4) invisible. becomes. The color of the one second image (5) does not change, and as a result, the latent image represented by the second image (5) is visible under specularly reflected light. This is the principle of the image change effect in the anti-counterfeit printed matter (1) of the present invention.

As described above, according to the present invention, the anti-counterfeit printed matter (1) having the effect of changing the image depending on the viewing angle can be produced by combining chromatic ink and achromatic ink. The above is the description of the first embodiment.

(Second embodiment)
In the second embodiment, in addition to the first image (4) and the second image (5), an anti-counterfeit medium ( 1). Since the basic configuration, production method, and the like of the first image (4) and the second image (5) are the same as in the example of the first embodiment, description thereof is omitted.

The method described in the first embodiment, that is, the method of complementing the density difference of the chromatic color in the first image (4) with the achromatic color of the second image (5), can be Depending on the color relationship of the colored inks, there may be cases where the second image (5) cannot be completely hidden. Specifically, in the chromatic color of the first image (4), when the color component of a specific hue is extremely high, or when the chromatic color of the first image (4) is a pale color with little black component is the case. In the second embodiment, in such a case, the second image (5) or the missing color component in the first image (4) is complemented by the third image (8), thereby This configuration enhances the concealing effect of the second image (5).

Suppose that the chromatic color of the first image (4) is yellow with high saturation, and in the portion where the second image (5) overlaps the first image (4), the yellow component If the latent image cannot be concealed due to the lack of the latent image, as shown in FIG. 7, the latent image portion (5A) of the second image (5) is filled with the missing yellow component of the third image (5). The second image (8) is overprinted on the second image (5). The third image (8) is formed using normal colored ink.

Also, if the chromatic color of the first image (4) is a light color with little black component, and the second image (5) portion of the printed image has a darker black component, the latent image If the image cannot be hidden, as shown in FIG. 8, a third image (8) obtained by filling in the background portion (5B) of the second image (5) composed of the missing black component is replaced with the second image (8). It is superimposed on the image (5) and reprinted.

Furthermore, if the chromatic color of the first image (4) is yellow with high saturation and the chromatic color of the first image (4) is a pale color with less black component, , the latent image portion (5A) of the second image (5) is filled with the missing yellow component, and the background portion (5B) of the second image (5) is filled with the missing black component. ) is overprinted on the second image (5).

In this way, the anti-counterfeit printed matter (1) of the second embodiment includes the first image (4), the second image (5), and the color of the third image (8). Thus, a printed image (3) is formed in which the concealability of the second image (5) is improved when observed under conditions in which diffusely reflected light is dominant. However, if the third image (8) is used on the other hand, there are many cases where the work is troublesome and basically the number of colors to be printed increases. It is desirable to complete with the form described in one embodiment.

In the form using the third image (8), process color printing based on black, blue, red, and yellow and printing with chromatic ink are performed in printing the anti-counterfeiting printed matter (1). It is desirable to apply it on the premise that In this case, it is easy to supplement the insufficient color components for concealment of the latent image by the process color printing section, and it is efficient without increasing the number of printing colors.

As for the stacking order of the third image (8), if the negative-positive state of the third image (8) and the second image (5) are the same as shown in FIG. is printed on a layer above the first image (4). Conversely, if the negative/positive states of the third image (8) and the second image (5) are reversed as shown in FIG. ) is desired to be printed on a layer below. This is a device for enhancing the visibility of the latent image appearing under specularly reflected light. In the form of FIG. 9, there is no particular difference whether the third image (8) is above or below the first image (4).

As described above, in addition to the first image (4) and the second image (5), by adding the third image (8) that complements the missing color components in each region, the The effect can be further enhanced by compensating for the color components that cannot be buried only by superimposing the first image (4) and the second image (5). The above is the description of the second embodiment.

In the present invention, the angle at which diffusely reflected light is dominant refers to an angle in which specularly reflected light is almost absent and the proportion of diffusely reflected light is extremely large. On the other hand, the angle at which specularly reflected light is dominant refers to an angle at which diffusely reflected light is less and the ratio of specularly reflected light is greater.

When superimposing the first image (4) and the second image (5), the redundancy of printing can be ensured by thickening the outline of the boundary portion of the images and overlapping the two images. can. Although the appropriate range differs depending on the density of the chromatic ink and the achromatic ink, specifically, an overlapping region of about 0.05 mm to 0.30 mm may be provided. As the overlap increases, printing becomes easier, but the density of the overlap increases and the hiding power of the latent image area (5A) decreases.

The printing method of the anti-counterfeit printed matter (1) in the present invention can be formed by any printing method such as offset printing, flexographic printing, letterpress printing, gravure printing, screen printing, and intaglio printing. In addition, if it is possible to use metal ink, it can be formed by various digital output machines such as IJP, laser printers, and sublimation printers. can be implemented.

In the first embodiment and the second embodiment, binary images are used for the visible image and the latent image, but the present invention is not limited to this. A multi-tone image may also be used.

Hereinafter, specific examples of anti-counterfeiting printed matter produced according to the above-described mode for carrying out the invention will be described in detail, but the present invention is not limited to these examples.

An example of the present invention will be described with reference to FIGS. 1 to 6 in the same manner as the embodiment. In the examples, white fancy paper (Gladios CC manufactured by Nippon Paper Industries Co., Ltd.) was used as the substrate (2).

The chromatic ink that forms the first image (4) is a bright pigment obtained by blending 10% of an interference color aluminum pigment (Chroma Shine, manufactured by Toyo Aluminum Co., Ltd.), which is a bright pigment with color flip-flop properties, into a UV varnish. A neutral ink was used. The ink has color flip-flop properties, being brown under diffusely reflected light and glowing pale yellow to green under specularly reflected light. Matte gray ink (UVL Special P420C matte gray manufactured by T&K TOKA) was used as the achromatic ink for forming the second image (5).

The reflection density of each part of the first image (4) and the second image (5) was the numerical value described in the embodiment, and the maximum reflection density of the second image (5) was set to 0.2. As for the stacking order of the printed image (3), the configuration shown in FIG. 5 was adopted. After the first image (4) was printed by UV screen printing using chromatic inks, the second image (5) was printed by UV offset printing using achromatic inks.

FIG. 6 shows the effect of the anti-counterfeit printed matter (1) of the present invention. FIG. 6(a) is an image that is visually recognized when an observer observes the anti-counterfeit printed matter (1) under diffusely reflected light. ” was visually recognized. On the other hand, as shown in FIG. 6(b), when the observer observes the anti-counterfeit printed matter (1) at a specific observation angle under specularly reflected light, the kanji character "sakura" is displayed in the printed image (3). The letters disappeared, and instead the latent image represented by the second image (5), the cherry blossom petal mark, was visible in brown in the yellow light. As described above, the effect of changing two different images was confirmed.

1 Anti-counterfeit printed matter 2 Base material 3 Printed image 4 First image 5 Second image 4A Information section 4A-1 First information section 4A-2 Second information section 4B Background section 4B-1 First background section 4B-2 Second background portion 5A Latent image portion 5B Background portion 6 Light source 7 Observer 8 Third image

Claims (3)

At least a part of the substrate is provided with a printed image of chromatic colors and partially different densities, and when observed under diffusely reflected light, a visible image due to the shades of the printed image is visually recognized, and when observed under specularly reflected light, A forgery-preventive printed matter in which a latent image is visually recognized, wherein the printed image is a first image formed with a chromatic ink having a luster and a second image formed with an achromatic ink superimposed. wherein the second image expresses the latent image by partially differing densities within a range in which the maximum density of the black component of the image formed with the achromatic ink is 0.5 or less, The forgery-preventive printed matter, wherein the first image has a density obtained by subtracting the density of the second image from the density of the printed image under diffusely reflected light, and the density is partially different. 2. The forgery prevention according to claim 1, wherein the difference between the maximum area ratio and the minimum area ratio of the first image is 70% or less, and the minimum area ratio of the first image is 20% or more. printed matter. At least a part of the substrate is provided with a printed image of chromatic colors and partially different densities, and when observed under diffusely reflected light, a visible image due to the shades of the printed image is visually recognized, and when observed under specularly reflected light, A counterfeit-preventive printed matter in which a latent image is visually recognized, wherein the printed image is formed with achromatic ink, and a second image showing the latent image by partially different densities, and diffusely reflected light. and a chromatic image having a density obtained by subtracting the density of the second image from the density of the printed image below and superimposed on the second image, wherein the chromatic image has glitter. A first image formed of chromatic ink having a partially different density, and an ink having the same hue as the ink forming the first image and / or formed of the achromatic ink, partially An anti-counterfeiting printed matter comprising a third image that reveals the latent image with different densities.

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