JPH1081060A - Copy preventing medium and method for producing the same - Google Patents

Abstract

(57) [Problem] To provide a copy protection medium having a forgery prevention effect by a color copier and a method for producing the same. A latent pattern is formed on at least two types of light reflecting portions A and B having different reflectivities on the surface of a copy preventing medium, and the latent pattern is made visible by a color copy machine. The latent pattern is formed by a physical method such as pressing a roughened surface of a stamper in a predetermined pattern against the metal thin film layer 13 provided on the base material 11. A different light reflection part is formed.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a copy protection medium having a function of discriminating a copy which has been forged or falsified by using a copying machine, and a method for producing the same.

[0002]

2. Description of the Related Art Banknotes, gift certificates, stock certificates, receivables, etc., such as banknotes, gift certificates, stock certificates, bonds, etc., which should have been subjected to advanced counterfeiting measures in recent years due to technological advances in copying machines such as color copiers. , Admission tickets, invitation tickets, commuter passes, and copies of copy-prevention media such as ID cards have come to market and have become a social problem. As a method of suppressing forgery using these copying machines, it has been conventionally known to form a part of information on a copy prevention medium using silver ink made of aluminum powder or the like. Even if the copy prevention medium using the silver ink is forged by a copying machine such as a color copier, the silver color of the glossy silver ink is not reproduced in the copy. Therefore, by looking at the silver color of the silver ink,
Since it is possible to determine whether a copy is a forged copy using a copying machine, silver ink has an effect of preventing forgery. Similarly, a hologram or a diffraction structure of a diffraction grating cannot be reproduced by a copying machine, and is provided on a part of a copy protection medium. Diffraction structures such as holograms and diffraction gratings can change the diffraction light dynamically by changing the observation direction and illumination direction. The authenticity of the copy prevention medium can be determined. Further, in Japanese Patent Application Laid-Open No. 7-309062, two types of halftone dots formed at different screen rulings having different pitches and having the same density are adjacently formed in a pattern so that they cannot be visually discriminated. It has been proposed to provide for copy protection media. When this copy protection medium is copied by a copying machine such as a color copying machine, the low resolution of the copying machine causes
The density balance of the different types of halftone dots has collapsed, and patterns have become apparent.

[0003]

The silver ink is obtained by mixing a flat metal powder made of aluminum or the like with a transparent vehicle, and has a variation in the direction of the flat metal powder. Therefore, from a macro perspective, the reflective surface of the silver ink is a rough surface. On the other hand, a color copier irradiates light from a light source at an angle of 45 degrees with respect to the normal to the surface of the copy object, and a light receiving unit installed at a direction of 0 degrees with respect to the normal to the surface. The scattered light from the surface is received, and the information of the copy object is reproduced according to the received light intensity.
Therefore, the reflection surface of the silver ink scatters and reflects light from the light source of the color copier, and makes a part of the reflected light incident on the light receiving portion of the color copier. Based on the intensity of this incident light, the color copier replaces the silver ink portion of the copy with
The reproduction is reproduced in a light grayish hue without gloss.
However, such a change in which the silver color with a weak shine of silver ink is reproduced in light gray in a copy is lacking in its own impact, so some people do not notice this change and copy the copy. May be mistaken for a genuine copy-prevention medium, and with such a change, there is a problem that counterfeiting by a copying machine cannot be suppressed. Also, when a hologram or a diffraction grating is provided in a part of the copy protection medium, the reproduced image of the hologram or the diffraction grating in the direction of 0 degree by the illuminating light incident from the direction of 45 degrees due to the structure of the color copier described above. Is reproduced on a copy. By the way, in the work of discriminating a copy in a short time at the time of congestion or the work of discriminating a copy in darkness,
A dynamic change in diffracted light due to the diffractive structure cannot be sufficiently confirmed, and there is a problem that a copy is mistaken for a real copy prevention medium. Furthermore, the method proposed in Japanese Patent Application Laid-Open No. 7-309062 relies on the resolution of the copying machine, so that the anti-counterfeiting effect is reduced as the performance of the copying machine, such as the resolution and reproducibility, is improved. There is a problem that is expected. SUMMARY OF THE INVENTION The present invention has been made in view of the above-described problems, and has as its object to provide a copy prevention medium and a method for preparing the same, which can easily perform the authenticity discrimination work only by visual observation.

[0004]

According to the present invention, there is provided a copy preventing medium comprising: a first light reflecting portion including a first metal thin film layer;
And a second light reflecting portion including the metal thin film layer, wherein the first metal thin film layer and the second metal thin film layer are made of the same material, and a surface of the first metal thin film layer is provided. Since the state is different from the surface state of the second metal thin film layer, the reflectance of the first light reflecting portion and the reflectance of the second light reflecting portion can be different. If a latent pattern is formed by the first light reflecting portion and the second light reflecting portion provided adjacent to each other, the reproduction state of the first light reflecting portion and the second light reflecting portion in the copy , A latent pattern appears. If a camouflage pattern is formed on the first light reflecting portion and the second light reflecting portion, the difference in reflectance between the first light reflecting portion and the second light reflecting portion in the copy preventing medium is determined by camouflage. can do. Individual information may be formed on the first light reflecting portion and the second light reflecting portion. Further, a method for producing a copy prevention medium according to the present invention is a method for producing a copy prevention medium having a first light reflection portion and a second light reflection portion, wherein a step of preparing a base material, Forming a metal thin film layer thereon, partially changing the surface state of the metal thin film layer, and forming the metal thin film layer whose partial surface state has not been changed to a first light reflecting portion. And the step of using the metal thin film layer whose surface state has been partially changed as a second light reflecting portion, so that the reflectance of the first light reflecting portion and the reflection of the second light reflecting portion Copy protection media with different rates can be made.

[0005]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described below in detail with reference to the drawings. FIG. 1 is a diagram for explaining the principle of a copy protection medium according to the present invention. Generally, in a copying machine, as shown in FIG. 1, light is radiated from a light source at an angle of 45 degrees with respect to the normal to the surface of the object to be copied, and the light is reflected and scattered on the surface of the object to be copied. Among the lights, there is adopted a method in which light reflected at an angle of 0 degrees with respect to the normal is received by a light receiving unit provided in that direction, the received light intensity is read, and the received light intensity is reproduced. In the present application, all angles are angles with respect to a normal line.
In addition, many copy-preventing media, which are to be copied, are multi-color printed. In a color copier, for each component of the three primary colors, the reflected light from the surface of the copy received at the light receiving unit is received. The received light intensity is measured, and the density gradation and color tone of the copy are reproduced according to the received light intensity. FIG. 1A is a diagram showing a case in which general white paper is used as a copy object. The illumination light is reflected and scattered on the surface of the copy object, and only the light reflected in the angle direction of 0 degrees reaches the light receiving unit, and the light receiving intensity is measured. Based on the received light intensity, the density gradation and color tone of the copy are reproduced on the copy. For general white paper,
The distribution of the reflected scattered light is substantially uniform, and the reflectance in the 0-degree angle direction is larger than that of silver ink or metallic luster described later, and is reproduced white in a copy by a copying machine. On the other hand, FIG. 1B is a diagram showing a case where a metallic glossy surface such as a mirror surface is used as a copy object. The illuminating light emitted at an angle of 45 degrees is specularly reflected at an angle of -45 degrees on a metallic glossy surface. do not do. Therefore, the metallic glossy surface is reproduced black on the copy by the copying machine. FIG. 1C is a diagram showing a case where the printing surface using silver ink is a copy object. The printing surface with silver ink,
The distribution of the reflected scattered light is more deviated in the regular reflection direction than general white paper, and exhibits an intermediate characteristic between general white paper and a metallic glossy surface. It is an intermediate value. Therefore, the printed surface of the silver ink is reproduced by the copier in a light gray color with no shine on the copy. The shine of the metallic glossy surface or the printing surface by silver ink is such that part of the light emitted from various angles is specularly reflected on the metallic glossy surface or the surface of the metal powder of the silver ink, and this reflected light is Because it comes into my eyes. By the way, a copier such as a color copier cannot receive regular reflection light and cannot reproduce a regular reflection surface due to its structure, and therefore cannot reproduce these glossy surfaces. Here, the ratio of the reflected light in the 0-degree angle direction of the copy to the illumination light from the light source provided in the 45-degree angle direction of the color copier, that is, the 45-degree irradiation and the 0-degree reflectance (Hereinafter, referred to as “reflectance 45-0”) can be expressed by the following equation. Reflectivity 45-0 = 0 reflected light amount at 0 degree / irradiated light amount at 45 degree × 100

The reflectance 45-0 of the light reflecting portion formed on the surface of the copy and the visual sensation, the reflection density and the visual sensation of the light reflection portion reproduced on the copy by the copying machine, and the Table 1 shows the results of examining the evaluation of the difference from the copy.

[Table 1] The light reflecting portion of the object to be copied as the sample for the above measurement is an aluminum-deposited surface, and by controlling the surface roughness of the substrate on which aluminum is deposited, light reflecting portions having different reflectivities of 45-0 are obtained. Was. The measurement of the reflectance 45-0 of the light reflection portion of the copy was performed using a visual filter with a Macbeth print contrast meter "PCM-2". Hereinafter, all values of the reflectance 45-0 are measured values by this apparatus. The reflection density of the light reflection portion reproduced in the copy was measured by a Macbeth reflection densitometer RD-918S (visual filter). This reflection densitometer irradiates illumination light from an angle direction of 45 degrees, receives a light amount reflected in an angle direction of 0 degrees, and performs reflection density conversion. Further, the column of visual sensation visually expresses the light reflection portion in the copy, and the reproduced light reflection portion in the copy, and the column of evaluation includes the light reflection portion of the copy and the copy. The light reflection portion reproduced in step (1) was shown to ten humans, and at a glance, it was confirmed whether or not a copy could be discriminated, and the number of discriminated persons was described. From Table 1, if the light reflecting portion of the copy is reproduced in black or dark gray with no shine in the copy, the difference becomes obvious, so that anyone can see the difference and copy the copy. Even a person who is not familiar with the object notices the abnormality of black or dark gray reproduced in the copy, so that the light reflecting portion has a function of authenticity determination. However, in the case where the object to be copied has only a single light reflecting portion, when copying with a copying machine such as a color copying machine, if the copy density is adjusted based on the reproduction color of the light reflecting portion in the copy. For example, in some cases, the light reflecting portion is reproduced in gray, and a person who does not know the copy cannot clearly determine whether or not the copy has been copied. Therefore, in the present invention, by providing two or more types of light reflecting portions having different reflectances on the copy-preventing medium, it is difficult to forge by adjusting the copy density and to reproduce the two or more types of light reflecting portions in the copy. Depending on the state, it can be clearly judged visually that the copy is a copy.

FIG. 2 is a plan view showing a copy protection medium according to the present invention. Hereinafter, for the sake of easy understanding, the “first light reflecting portion” has a reflectivity of 45−− more than the “second light reflecting portion”.
Description will be made assuming that 0 is small. As shown in FIG. 2A, the copy protection medium 1 includes an individual information display area K and a latent pattern area S. Individual information display area K
For example, if it is a bank note, it consists of characters such as amount, serial number, name of factory, etc., and figures such as a person image, Bank of Japan seal, Ayamon, etc. Individual information 4 unique to the medium itself is provided by appropriate means such as printing or printing. In the latent pattern region S, two types of light reflecting portions having different reflectivities 45-0, that is, a first light reflecting portion A and a second light reflecting portion B are provided adjacent to each other. A latent pattern 3 is formed by the boundary between the light reflecting portions A and B. Latent pattern 3
May be appropriately selected from warning characters or marks such as "copy", "fake", and "invalid". The light reflecting portions A and B
Is such that the difference between the light reflecting portions A and B in the copy protection medium can be overlooked by visual observation. Preferably in the range of 10 to 10 percent,
A range of 3 to 5% is desirable from the balance between the two. Here, the difference between the reflectances 45-0 of the light reflecting portions A and B is
If it exceeds 10%, it is a genuine copy protection medium 1.
However, since the latent pattern 3 that must be difficult to see becomes apparent and can be easily identified by visual inspection, the copy prevention medium may be mistaken for a copy. Further, if the difference between the reflectances 45-0 of the light reflecting portions A and B is less than 2%, even a copy copied by a color copier becomes apparent due to the difference in reflectance between the two light reflecting portions. In some cases, the latent pattern 3 that should be performed does not become apparent, and the copied matter cannot be easily recognized. Further, in order to make the latent pattern 3 of the copy preventing medium 1 more difficult to recognize, the camouflage pattern 5 composed of fine characters, patterns, wavy lines, etc.
Is formed by printing.

FIG. 2B is a view showing a copy 2 obtained by copying the copy protection medium 1 shown in FIG. 2A by a copying machine such as a color copying machine. The individual information display area K ′ of the copy 2 is reproduced almost in the same manner as the individual information display area K of the copy protection medium 1. On the other hand, in the reproduction area S 'of the latent pattern area of the copy 2 corresponding to the latent pattern area S of the copy protection medium 1, as shown in FIG. 2B, the reproduction area A' of the first light reflection portion A. Due to the difference in the reproduction state of the reproduction area B ′ of the second light reflection portion B, the latent pattern 3 that was difficult to see on the copy prevention medium 1 becomes apparent in the copy 2 and easily becomes a check pattern 3 ′. You will be able to see it visually. The manifestation of this latent pattern 3
Unlike a delicate change in density or color tone of a specific portion of the copy protection medium 1, a pattern that is difficult to see on the copy protection medium 1 appears in a copy, and therefore has an impact. Therefore,
Even if a person who is not familiar with the copy protection medium 1 can see the abnormality just by looking at the copy, the function of judging the copy by this manifestation has a great effect.

Further, as described above, a metallic glossy surface such as an aluminum vapor-deposited surface is reproduced as light gray in a copy when the reflectance 45-0 exceeds 30% and becomes 40 to 50%. The function of determining a copy is reduced. However, by having two types of light reflecting portions as in the copy prevention medium of the present invention, even if the reflectance 45-0 exceeds 30%, the copy does not have a thin fog on the reproduced light reflecting portion. Has occurred, but in that,
The reproduction areas of the two light reflecting portions having different densities are in a state of being seen. When the reflectance 45-0 of the light reflection portion exceeds 30%, the light reflection portion becomes slightly glossy, and unnaturalness when the entire copy protection medium is viewed is reduced.

Here, the location of the copy protection medium 1 where the latent pattern 3 is provided is not limited to the example of FIG. 2A, and may be any position on the copy protection medium 1. It is preferable to provide the forged copy in a place where the copy is easily noticeable using a copying machine. Further, the latent pattern display area S and the individual information display area K do not need to be partitioned as shown in FIG. 2A, and may overlap as appropriate, and the individual information display 4 is placed on the light reflecting portions A and B. May be provided.

Next, a method for producing a copy protection medium according to the present invention will be described. FIG. 3 is a schematic cross-sectional view for explaining the latent pattern area S of the copy protection medium 1 according to the present invention. In the embodiment shown in FIG. 3, a metal thin film layer 13 is formed on a base material 11 by a vacuum evaporation method. Next, when the surface of the metal thin film layer 13 is partially embossed by a stamper 14 having an uneven surface, the surface of the metal thin film layer 13 is roughened according to the surface roughness of the uneven surface. The reflectance 45-0 of the embossed surface 12 of the embossed metal thin film layer 13 is increased as compared with the surface of the non-embossed metal thin film layer 13. Here, the surface of the metal thin film layer 13 that has not been embossed is referred to as a first light reflecting portion, the embossed surface 1.
Reference numeral 2 denotes a second light reflecting portion. As the substrate 11, any material having high adhesion to metal can be used, and for example, a plastic sheet of a polyvinyl chloride sheet can be used. Further, even those having poor adhesion to metal can be used by providing an anchor layer such as a polyester resin between the base material 11 and the metal thin film layer 13. Further, in the case of high-quality paper such as high-quality paper having poor permeability and surface state, a filler layer of vinyl chloride-vinyl acetate copolymer resin or the like may be provided. Metal thin film layer 13
As a material, a metal reflecting material, for example, a metal such as aluminum can be used, and is formed to have a thickness capable of sufficiently reflecting light, for example, a thickness of 200 to 1000 angstroms. The metal thin film layer 13 can be formed by a thin film forming means such as a vacuum evaporation method and a sputtering method. Instead of a simple metal such as aluminum, a transparent metal compound having a high refractive index such as zinc sulfide is used as the metal thin film layer 13.
As may be used. A metal compound having a high refractive index reflects a part of incident light in a specular reflection direction due to a difference in refractive index at an interface, so that a copy of a portion where a metal compound is formed is compared with a portion where no metal compound is formed. It is reproduced with darkness. A metal compound having a high refractive index does not have a metallic luster in a copy protection medium like a metal simple substance, and the naturalness as a copy protection medium increases. When the surface of the base material 11 is not smooth, the metal thin film layer 13 has a constant reflectance 45-0 according to the surface roughness of the base material 11, By providing an anchor layer, the reflectance 45-0 of the metal thin film layer 13 can be controlled by the amount and particle size of the fine particles added to the material of the anchor layer. Stamper 14
As the stamper, a bumper made of nickel or the like having a pattern formed in a pattern shape can be used.
The uneven surface is embossed on the metal thin film layer 13.
As a method of forming an uneven surface on the stamper 14,
Conventional methods for forming concavities and convexities, such as etching, polishing with an abrasive, and sandblasting, may be used. The embossing method may be a flat pressure method as shown in FIG. 3, or a roll method in which the stamper 14 is wound around a metal roll, that is, a linear pressure method. , Embossing with high reproducibility can be performed. Further, when the layer adjacent to the metal thin film layer 13 is a thermoplastic resin, if the stamper 14 is heated, embossing becomes easy.

FIG. 4 is a sectional view showing the completed copy preventing medium. The copy protection medium 1 has a camouflage pattern printing layer 15 made of a color pattern printed thereon by a printing method such as offset printing or silk printing. Further, the individual information print layer 16
Is provided by printing or printing. Finally,
Protective layer 1 made of polyester resin or acrylic resin
7 are provided. Although the embodiments of the present invention have been described above, the present invention is not limited to these embodiments, and various modifications are possible within the scope of the invention. Instead, three or more types may be used. In addition, instead of embossing an uneven surface on the surface of a smooth metal thin film layer, embossing is performed on a rough metal thin film layer with a stamper having a smooth surface as a convex part, and partially embossing. A smooth surface may be created. In addition, as the protective layer 17, a transparent plastic film may be laminated, or a colored layer in which a dye or a pigment is mixed in a polyester resin or an acrylic resin may be provided.

(Example 1) An anchor agent made of a polyester resin was applied to the entire surface of a base material made of high-quality paper (90 kg / m ² ) to a thickness of 10 μm by gravure printing to form a filling layer. The center line average roughness (R
a) was 0.18 to 0.20 μm. Next, aluminum was vacuum-deposited on this filling layer to a thickness of 500 Å to provide a metal thin film layer. The reflectance 45-0 of this metal thin film layer was 10%. On the other hand, a nickel stamper having a convex portion in the form of a background portion excluding the character portion of "COPY", which is a latent pattern, was formed, and the surface of the convex portion was polished with a polishing tape to form surface irregularities. The stamper and the metal thin film layer are superimposed on each other, and a pressure of 10 kg / cm ² is applied to emboss the surface irregularities of the protrusions of the stamper on the surface of the metal thin film layer. Was formed, and a second light reflecting portion having surface irregularities serving as a background thereof was formed. Here, the center line average roughness (Ra) of the first light reflecting portion is 0.19 μm, the reflectance 45-0 is 13%, and the center line average roughness of the second light reflecting portion is Ra. Its (Ra) was 0.25 μm and its reflectivity 45-0 was 17%.
Next, using an ink containing a blue dye, a camouflage pattern printing layer composed of a color pattern was formed by gravure printing. The individual information display was performed by gravure printing to form an individual information print layer. Further, a protective layer was provided by gravure printing on the camouflage pattern printing layer and the individual information printing layer, thereby completing a copy prevention medium. In the copy prevention medium thus created, the latent pattern “CO” consisting of the boundary between the first light reflecting portion and the second light reflecting portion is used.
“PY” was difficult to determine visually. Also,
This copy prevention medium is transferred to a color copier (CLC500,
When the image was copied by Canon Inc., the character "COPY" as a latent pattern became apparent, and it could be easily identified as a copy.

[0014]

According to the present invention, there is provided a copy protection medium having a first light reflection portion including a first metal thin film layer and a second light reflection portion including a second metal thin film layer. So,
Since the first metal thin film layer and the second metal thin film layer are made of the same material, and the surface state of the first metal thin film layer and the surface state of the second metal thin film layer are different, the first light reflecting portion Can be made different from the reflectance of the second light reflecting portion, so that a difference occurs in the reproduction state of the first light reflecting portion and the second light reflecting portion in the copy, and the copying machine In addition to making forgery by adjusting the density difficult, it is possible to clearly judge that the copy is a copy, and it is possible to suppress forgery of the copy protection medium by the copy machine and to prevent use of the copy. it can. If the latent pattern is formed, the latent pattern appears due to the difference in the reproducibility between the first light reflecting portion and the second light reflecting portion in the copy, so that a person who does not know the real copy protection medium However, it is possible to easily determine the copy. If the camouflage pattern is formed, it is possible to camouflage the difference in reflectance between the first light reflecting portion and the second light reflecting portion in the copy prevention medium. The difference between the reflection portions can be hardly distinguished visually. Also,
A method for producing a copy protection medium according to the present invention is a method for producing a copy protection medium having a first light reflection portion and a second light reflection portion, comprising the steps of: preparing a base material; ,
Forming a metal thin film layer, partially changing the surface state of the metal thin film layer, and using the metal thin film layer having the partially changed surface state as a first light reflecting portion; Using the metal thin film layer, the surface state of which has not been partially changed, as a second light reflecting portion, the light reflectance of the first light reflecting portion and the light reflectance of the second light reflecting portion. Are different in the reproduction state of the first light reflection portion and the second light reflection portion in the copy, making it difficult to forge by adjusting the density of the copying machine and copying the copy. Thus, it is possible to make a clear determination by visual inspection, to prevent forgery of the copy protection medium by the copying machine, and to create a copy protection medium capable of preventing the use of the copy.

[Brief description of the drawings]

FIG. 1 is a diagram for explaining the principle of a copy protection medium according to the present invention.

FIG. 2 is a plan view showing a copy protection medium according to the present invention.

FIG. 3 is a schematic sectional view for explaining a latent pattern area S of the copy protection medium 1 according to the present invention.

FIG. 4 is a sectional view showing a completed copy prevention medium.

[Explanation of symbols]

 REFERENCE SIGNS LIST 1 copy prevention medium 2 copy 3 latent pattern 3 ′ check pattern 4 individual information 5 camouflage pattern 11 base material 12 embossed surface 13 metal thin film layer 14 stamper 15 camouflage pattern print layer 16 individual information print layer 17 protective layer A first light Reflecting section B Second light reflecting section A 'Reproducing area of first light reflecting section B' Reproducing area of second light reflecting section K Individual information display area K 'Reproducing area of individual information displaying area S Latent pattern area S '' Reproduction area of latent pattern area

Claims (5)

[Claims] 1. An anti-copy medium having a first light reflecting portion including a first metal thin film layer and a second light reflecting portion including a second metal thin film layer, wherein the first metal reflection layer includes a first metal reflection layer. A copy protection medium, wherein the thin film layer and the second metal thin film layer are made of the same material, and the surface condition of the first metal thin film layer is different from the surface condition of the second metal thin film layer. 2. The copy protection medium according to claim 1, wherein a latent pattern is formed by the first light reflection portion and the second light reflection portion provided adjacent to each other. 3. The copy protection medium according to claim 1, wherein a camouflage pattern is formed on the first light reflecting portion and the second light reflecting portion. 4. The copy protection medium according to claim 1, wherein individual information is formed on the first light reflecting portion and the second light reflecting portion. 5. A method for producing a copy prevention medium having a first light reflecting portion and a second light reflecting portion, comprising: preparing a base material; and forming a metal thin film layer on the base material. Performing the step of partially changing the surface state of the metal thin film layer; the step of using the metal thin film layer whose surface state has not been partially changed as the first light reflection portion; Using the metal thin film layer whose surface condition has been changed as a second light reflecting portion.