JP2017030326A - Counterfeit prevention document and method for manufacturing counterfeit prevention document - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a counterfeit prevention document which comprises a watermark ensign part having a high counterfeit prevention effect, and a method for manufacturing the same.SOLUTION: A counterfeit prevention document comprises a watermark ensign part which is configured from a watermark main image 11 which can be visually recognized by transmission of light, and a watermark confidential image 12 which has a lower light transmissivity compared with the watermark main image 11. Therefore, although the watermark main image 11 can be visually recognized when the image is visually inspected therethrough, the watermark confidential image 12 is hard to be visually inspected. Consequently, the watermark confidential image 12 is hard to be copied and authenticity determination can be performed by existence or absence of the watermark confidential image 12 thereby enhancing counterfeit prevention effect. Further, since the watermark main image 11 and the watermark confidential image 12 can be printed by one printing plate, a time and a cost required for a printing process can be suppressed thereby enhancing productivity.SELECTED DRAWING: Figure 3

Description

  The present invention relates to an anti-counterfeit form used for securities and certificates, and a method for manufacturing an anti-counterfeit form.

  Various forms such as securities and certificates have been proposed that have an image that can determine authenticity and prevent counterfeiting. Specifically, a form in which a watermark mark is formed on a base paper is conventionally known. Since the watermark mark can be visually recognized by seeing through the paper surface, whether or not the watermark mark is visible can be determined as to whether the watermark mark is a genuine form. As this watermark mark, what is constituted by unevenness formed on the base paper is well known. The watermark mark having such a configuration can be visually recognized by causing a difference in light transmittance due to the difference in thickness due to the unevenness and making the paper surface transparent.

  On the other hand, the watermark mark has been proposed to be printed with an ink containing titanium oxide as a white pigment in addition to the above-described configuration of the unevenness of the paper surface (for example, Patent Document 1). In such a configuration, the portion printed with the ink has a lower light transmittance than the portion not printed with the ink, so that the watermark mark can be visually recognized through the paper.

JP 2001-26177 A

  By the way, in many cases, the watermark mark described above is a relatively simple character or pattern so that it can be easily determined authenticity when viewed through the paper. The watermark mark itself is widely known, and its formation technique is already known as described above. For this reason, the watermark mark may be easily confirmed and copied, and its anti-counterfeiting effect is limited. Therefore, a watermark mark having a high anti-counterfeit effect has been demanded.

  The present invention proposes an anti-counterfeit form provided with a watermark mark that exhibits a high anti-counterfeit effect, and a method for manufacturing the anti-counterfeit form.

  The present invention provides a watermark mark in which the transmissivity is different between a printed portion on which a paper-colored light-shielding ink containing titanium oxide as a white pigment is printed and applied to a non-printed portion on which the surface is not coated. The watermark mark portion includes a watermark main image that is visible by light transmission and a watermark that is less visible by light transmission than the watermark main image. A forgery prevention form characterized by comprising a secret image.

  In such a configuration, the watermark mark portion can be visually recognized by distinguishing the watermark portion by viewing the watermark portion because the light transmittance is lower than the non-print portion in the printed portion on which the shielding ink is printed. Therefore, the watermark main image constituting the watermark mark portion can be visually recognized. In addition to the watermark main image, the watermark mark portion includes a watermark concealment image that is difficult to visually recognize when viewed through a watermark. Here, it can be said that a general “watermark mark” can visually recognize an image by viewing it through a watermark, and it can be said that it can be visually recognized visually. Therefore, according to the configuration of the present invention, since the watermark main image can be visually recognized by viewing through the watermark, it is difficult to conceive that there are further watermark concealed images that are difficult to visually recognize, and the effect of hiding the existence is extremely high. . As a result, for example, a person who tries to forge is satisfied that the watermark main image can be visually recognized, and it is difficult to conceive the existence of the watermark confidential image. Therefore, only the watermark main image is copied and forged. And since this watermark does not have a watermark concealment image, it can be accurately and easily determined to be a fake by authenticity determination. Thus, according to the configuration of the present invention, the effect of preventing forgery can be improved.

  Here, the watermark main image is formed by an image composed of a printing portion on which a light-shielding ink is applied, an image composed of a non-printing portion defined by the printing portion, and both the printing portion and the non-printing portion. Any of the images may be used. Even in the case of the watermark concealment image, the image may be any of the image formed by the printing unit, the image formed by the non-printing unit, and the image formed by both.

  Note that since the watermark concealment image is difficult to visually recognize only by viewing through the watermark, it is required to use a specific device that can visually recognize the watermark concealment image for authenticity determination.

  In the forgery prevention form of the present invention described above, a configuration is proposed in which the watermark concealment image is composed of one or a plurality of micro characters having a character size of 100 μm or more and 1000 μm or less.

  Here, the micro characters may be not only characters constituting a language such as hiragana, katakana, kanji, and English characters, but also numbers and symbols. As the symbols, graphic symbols such as “◯”, “Δ”, and other symbols such as “×”, “+”, “→” can be used. Further, it is preferable that the watermark concealed image has a plurality of micro characters arranged in a predetermined order so as to indicate predetermined concealment information. Thereby, authenticity determination can be performed more easily and accurately. In addition, as a micro character, a character size of 200 μm or more and 800 μm or less is preferable in consideration of balance between confidentiality, printing accuracy, and productivity.

  In such a configuration, since the watermark concealment image is composed of extremely fine micro characters, when viewed through the watermark, the watermark concealment image is extremely difficult to be seen and has high concealment. This is because it is difficult to see even if it is a very fine micro character, and the micro character can be seen by the difference in transmittance between the printed portion and the non-printed portion on which the paper-color shading ink is applied. It depends on what you are doing. Therefore, the watermark concealment image of this configuration is harder to be duplicated, and since it is possible to reliably determine a fake by authenticity determination, the forgery prevention effect is further improved.

  In the forgery-preventing form of the present invention described above, a configuration is proposed in which the watermark concealment image is composed of colored text drawn with an ultrathin line having a width of 200 μm or less. Here, considering the balance between secrecy, printing accuracy, and productivity, it is preferable that the fine line of the coloring has a line width of 100 μm or more and 200 μm or less.

  Since the watermark concealment image having such a configuration is drawn with ultra fine lines, it is extremely difficult to visually recognize the image when viewed through the watermark and has high concealment. This is due to the fact that the ultra-thin line can be seen by the difference in transmittance between the printed portion and the non-printed portion on which the paper-colored light-shielding ink is applied. Therefore, the watermark concealment image of this configuration is harder to be duplicated, and since it is possible to reliably determine a fake by authenticity determination, the forgery prevention effect is further improved.

  In the forgery prevention form of the present invention described above, the light-shielding ink is proposed to have a titanium oxide content of 30% or more and 70% or less.

  In such a configuration, by setting the content of titanium oxide in the above range, it is possible to cause a clear difference in the transmittance between the printed portion and the non-printed portion. The main image is clearly visible. Furthermore, since the light-shielding ink having this content is excellent in workability during printing, the productivity is high during production.

  In addition, as the light-shielding ink, one having a titanium oxide content of 40% or more and 60% or less is more preferable. By setting it as this content, the above-mentioned effect is further improved.

  On the other hand, the present invention is a method for manufacturing the forgery-preventing form described above, comprising a printing step of printing a watermark mark portion by one printing plate for printing a watermark main image and a watermark concealment image. It is a manufacturing method of the forgery prevention form characterized.

  In this method, since both the watermark main image and the watermark concealment image can be printed at once by printing with one printing plate, the time and cost for the printing process can be suppressed. Here, the watermark concealment image constitutes a watermark mark portion together with the watermark main image, and is printed on the one printing plate with the shading ink. Then, by appropriately determining the printing conditions, both can be printed with one printing plate, and even the extremely fine images such as the above-described micro image or extra fine line coloring can be printed with high accuracy. Therefore, according to this manufacturing method, the forgery prevention form which exhibits the desired effect mentioned above can be manufactured stably, and its productivity can be improved.

  As described above, the forgery-preventing form of the present invention includes a watermark mark portion that is composed of a watermark main image that is visible through light transmission and a watermark concealment image that is less transparent than the watermark main image. Therefore, when viewed through a watermark, the watermark main image can be viewed, but the watermark concealed image is difficult to view. Therefore, even if it is duplicated, since the watermark concealment image is difficult to be duplicated, it is possible to accurately and easily determine the authenticity based on the presence or absence of the watermark concealment image. Therefore, the forgery prevention form of the present invention is highly effective in preventing forgery.

  In addition, as described above, the method for manufacturing a forgery-preventing form according to the present invention is a method in which the watermark main image and the watermark concealment image are printed with a single printing plate. And productivity is high.

It is explanatory drawing which expands and shows the watermark mark part 2 of the forgery prevention form 1 of Example 1. FIG. It is explanatory drawing at the time of seeing the watermark mark part 2 through the watermark. It is explanatory drawing which expanded and looked at the X section in FIG. 2 with the microscope of UV illumination type. It is explanatory drawing which shows the watermark printing process in the manufacturing process of the forgery prevention form. It is explanatory drawing which expands and shows the watermark mark part 32 of the forgery prevention form 31 of Example 2. FIG. It is explanatory drawing when the watermark mark part 32 is seen through. It is explanatory drawing which expanded and looked at the Y section in FIG. 6 with the microscope of UV illumination type. It is a graph which shows the result of having observed the watermark mark part 2 of Example 1 and the result of having observed the watermark mark part 32 of Example 2 (b).

  Embodiments according to the present invention will be described according to the following Examples 1 and 2.

  The counterfeit prevention form 1 of the first embodiment is used for securities, certificates, etc., and the watermark mark part 2 is printed on the surface of the white base paper 10 as shown in FIGS. Yes. The watermark mark portion 2 is formed by printing and applying the same white light-shielding ink as that of the base paper 10. In addition, the base paper 10 of a present Example is a sheet-like base material concerning this invention.

  Here, the light-shielding ink is made of an ultraviolet curable ink containing titanium oxide, which is a white pigment, and is cured by irradiating ultraviolet light after printing and coating, and thus has quick drying properties and heat resistance. For this reason, it is suitably used for printing means such as a laser printer that rapidly applies high heat and requires quick drying, and has high printing accuracy and good finish.

  Since titanium oxide, which is a white pigment, has an effect of blocking light, in the watermark mark portion 2, the printing portion 5 on which the light-shielding ink is printed is compared with the non-printing portion 6 on which the light-shielding ink is not printed. Therefore, the light transmittance is low. In particular, in Example 1, since the light-shielding ink has a titanium oxide content of 40% to 60%, the difference in transmittance between the printing unit 5 and the non-printing unit 6 is relatively large. Therefore, when the paper is viewed through the paper, the printing unit 5 and the non-printing part 5 are not printed as shown in FIG. The image formed with the portion 6 can be clearly seen.

  In addition, as shown in FIG. 1, the forgery prevention form 1 of the first embodiment has halftone printing or the same on the surface of the base paper 10 so as to cover the watermark mark portion 2 formed by printing and applying a light-shielding ink. A decorative pattern 7 for concealment is formed by repeated printing of figures. The decorative pattern 7 is printed with colored ink. For this reason, the watermark pattern portion 2 can be more effectively concealed by the decoration pattern 7, and the watermark mark portion 2 cannot be confirmed unless it is viewed through light.

Next, the main part of the present invention will be described.
In the first embodiment, as shown in FIG. 1, the watermark mark part 2 includes a printing part 5 formed in a predetermined pattern (for example, a flower pattern) and a non-printing part 6 around the printing part 5. Composed. When the watermark mark portion 2 is viewed through light, the flower image indicated by the printing portion 5 can be visually recognized due to the difference in transmittance between the printing portion 5 and the non-printing portion 6 as shown in FIG. . The flower image that can be seen through the watermark mark portion 2 in this way is the watermark main image 11 according to the present invention.

  Here, since the printing part 5 of Example 1 is formed by printing and coating so that the light-shielding ink is solidly applied, the boundary with the surrounding non-printing part 6 is clearly expressed. Therefore, when viewed through a watermark, the watermark main image 11 can be viewed more clearly.

  Further, in the first embodiment, as shown in FIG. 3, the watermark concealment image 12 composed of a plurality of micro characters is formed as a white image without applying the light-shielding ink inside the printing unit 5. The watermark concealment image 12 is configured by arranging a plurality of micro characters having a character size of 300 μm to 400 μm, and may be formed, for example, by arranging a plurality of alphanumeric characters in a predetermined order. The watermark concealment image 12 is difficult to see even if it is an extremely small micro character, and can be viewed due to a difference in transmittance with the light-shielding ink applied to the periphery. It cannot be visually recognized only by doing (see FIG. 8A). Furthermore, in the configuration of the first embodiment, since the printing unit 5 is formed by solid coating of light-shielding ink and the boundary with the surrounding non-printing unit 6 is clear, the watermark main image is viewed when viewed through a watermark. 11 is clearly visible, but the watermark concealed image 12 outlined in the printing unit 5 is not conspicuous, and the effect of concealing the presence of the watermark concealed image 12 is high.

  Such a watermark concealment image 12 can be visually recognized by using, for example, a microscope. However, there are various types of microscopes, and the types that can clearly see the watermark concealment image 12 are limited. A general optical microscope irradiates an object with visible light and observes it with an optical lens. A ring illumination type in which a light source is arranged obliquely above the object, or the light source directly above the object. There are epi-illumination types and so on. As a result of observing the watermark mark portion 2 with a ring illumination type microscope, it was difficult to visually recognize the watermark concealment image 12 as shown in FIG. This is because, since the light source is obliquely above the object, it is difficult for a difference in brightness to occur between the light reflected on the paper surface and the light reflected on the ink surface coated with the light-shielding ink. Further, as a result of observation with an epi-illumination type microscope, the presence of the watermark concealment image 12 can be visually recognized, but it is difficult to clearly see the content. This is because the light irradiated from directly above is specularly reflected, and this is due to the difference in brightness of the reflected light due to the difference in smoothness between the ink surface coated with light-shielding ink and the paper surface not coated. Since the difference is small, the contents cannot be clearly seen as described above. On the other hand, some optical microscopes are of the UV illumination type that emits ultraviolet light. The UV illumination type has a limited use and is expensive as compared with the type that emits visible light. When the watermark mark portion 2 is observed with a UV illumination type microscope, the watermark concealment image 12 can be clearly seen and the contents thereof can be clearly confirmed. This is because, while paper reflects ultraviolet light, the light-shielding ink of the present invention absorbs ultraviolet light, so that there is a clear difference in reflected light between the paper surface and the ink surface. Note that if the electron microscope such as SEM is used, the watermark concealment image 12 can be clearly seen, but the use of the electron microscope is more limited and more expensive.

  Thus, in order to visually recognize the watermark concealment image 12 accurately, a special microscope is required and it is extremely difficult to visually recognize it. And since the visual recognition method is limited, the confidentiality of the watermark concealment image 12 is extremely high. Note that the method of visually recognizing the watermark concealment image 12 is limited to the fact that the watermark concealment image 12 can be viewed due to a difference in transmittance with the surrounding light-shielding ink, in addition to being a very small micro character. The

  When the anti-counterfeit form 1 of the first embodiment is viewed through the light, it reflects the light at the printing unit 5 of the watermark mark part 2 and transmits the light at the non-printing part 6, so that the contrast causes the The watermark main image 11 constituting the watermark mark part 2 can be clearly seen. This watermark main image 11 can be used for authenticity determination of the forgery prevention form 1, and as described above, when the forgery prevention form 1 is used for securities, certificates, etc., it is visually observed through light. By doing so, the presence or absence can be confirmed, and the authenticity of the securities or certificates can be determined. The counterfeit prevention form 1 is formed by printing the watermark mark portion 2 with the same white shielding ink as that of the base paper, and is covered with the decorative pattern 7, so that the watermark mark is not transparent to light. The presence of the part 2 cannot be confirmed, and the effect of hiding the watermark mark part 2 is high.

  Further, the watermark mark portion 2 of the first embodiment also includes a watermark concealment image 12 composed of a plurality of micro characters. Since the watermark concealment image 12 is not only a very small micro character but also visible due to a difference in transmittance with the surrounding light-shielding ink, it cannot be visually recognized only by seeing through the watermark as described above. Furthermore, it is difficult to visually recognize even a general optical microscope using visible light, and a special microscope such as a UV illumination type optical microscope or an electron microscope is required to clearly view the watermark concealment image 12. And As described above, since the watermark concealment image 12 has extremely high concealment and cannot be visually recognized without using the special microscope, the authenticity determination accuracy of the forgery prevention form 1 can be remarkably improved by using it for authenticity determination. That is, the watermark main image 11 is relatively easy to see by seeing through the light, and may be duplicated. However, the watermark concealment image 12 cannot be visually confirmed, and the contents of the image are accurately displayed. Since it requires a special microscope to know, it is very unlikely to be duplicated. Therefore, authenticity of the watermarked confidential image 12 can be determined with high accuracy by authenticating it using a UV illumination type microscope. Since the watermark concealment image 12 is composed of a plurality of micro characters, even if a person who tries to forge can confirm the presence and content of the image, it cannot be reproduced with high accuracy. It is extremely difficult. Therefore, the effect of preventing forgery is also high.

  Further, if the watermark concealment image 12 is a predetermined information content represented by a plurality of micro characters, the information content can be easily known by visually recognizing with the above-mentioned special microscope. It is also possible to effectively increase the accuracy of authenticity determination.

Next, the manufacturing method of the forgery prevention form 1 of Example 1 mentioned above is demonstrated.
The process for producing the forgery prevention form 1 includes a first printing process for printing the watermark mark portion 2 on the surface of the base paper, a second printing process for printing the decorative pattern 7, and a third printing for printing desired information. A printing process. In addition, when the forgery prevention form 1 is configured to further include a latent image or the like in addition to the watermark mark portion 2, a printing process for printing the latent image is also performed. The second printing process, the third printing process, the latent image printing process, and the like described above can be performed in the same manner as the previous printing process, and thus the details thereof are omitted.

  Said 1st printing process is comprised from the watermark printing process which prints the watermark mark part 2 on a base paper, and the drying process which dries the light-shielding ink which carried out printing application | coating. In the watermark printing process, as shown in FIG. 4, a plate roller 52 having a printing plate 57 on its outer peripheral surface, a pressure roller 53 disposed so as to face the plate roller 52, and the plate roller 52 A plate printing apparatus 51 provided with an ink roller 54 for attaching light-shielding ink is used. The printing plate 57 on the outer peripheral surface of the plate roller 52 is formed with irregularities (not shown), and the ink roller 54 comes into contact with the surface of the printing plate 57, thereby causing the printing plate 57 to move from the ink roller 54. The light-shielding ink is attached to the convex portion (not shown). The watermark mark portion 2 is printed by transferring the shading ink from the printing plate 57 of the plate roller 52 onto the surface of the base paper 10 passing between the plate roller 52 and the pressure roller 53. Here, the printing plate 57 of the plate roller 52 transfers the light-shielding ink attached to the convex portion and performs printing application, so that the convex portion forms the shape of the printing portion 5. Furthermore, a concave portion that forms the shape of the watermark concealment image 12 is formed on the convex portion.

  As described above, the plate roller 52 provided with the one printing plate 57 is pressed against the surface of the base paper 10 to transfer the light-shielding ink attached to the convex portions to the surface of the base paper 10, thereby 5 and the non-printing part 6 are formed. Thereby, the watermark mark part 2 provided with the watermark main image 11 and the watermark concealment image 12 is printed. Here, in this embodiment, light-shielding ink is attached from the ink roller 54 to the convex portion of the printing plate 57 so that the watermark main image 11 can be clearly printed and the watermark concealed image 12 can be printed with high accuracy. The amount of adhesion is set appropriately. The amount of adhesion is set as appropriate according to the character size of the micro characters constituting the watermark concealment image 12.

  After the watermark printing process by the plate printing apparatus 51, the drying process is performed (not shown). In the drying process, the surface of the base paper to which the light-shielding ink is transferred is irradiated with ultraviolet light. Since the light-shielding ink is an ultraviolet curable ink as described above, it is cured by ultraviolet light, so that the printing unit 5 can be fixed on the surface of the base paper by irradiating with ultraviolet light in this drying step. In addition, since such a drying process can be implemented similarly to the past, it abbreviate | omits about the detail.

  In the manufacturing method of the present embodiment, as described above, the watermark main image 11 and the watermark concealment image 12 can be printed at one time by the one printing plate 57 (plate roller 52) in the watermark printing step. The time and labor required for printing of the section 2 can be reduced as much as possible. In particular, although the watermark concealment image 12 is an extremely fine image composed of micro characters, by appropriately setting the amount of shading ink to be adhered to the printing plate 57 of the plate roller 52, one printing plate 57 can be printed simultaneously with the watermark main image 11. Therefore, according to the watermark printing process of the present embodiment, the watermark mark portion 2 can be printed with high accuracy and the productivity thereof is high.

  In this embodiment, the watermark printing step is a printing step according to the present invention, and the printing plate 57 on the outer peripheral surface of the sales roller 52 is one printing plate according to the present invention.

  As shown in FIGS. 5 and 6, the forgery prevention form 31 of the second embodiment includes a watermark mark portion 32 that includes the same watermark main image 11 as that of the first embodiment, and is drawn with a thin line having a width of 200 μm using light-shielding ink. A watermark concealment image 42 made up of colored shapes is provided. The configuration of the second embodiment is the same as that of the above-described embodiment, except that the watermark mark unit 32 does not include the watermark concealment image 12 made of micro characters but has the watermark concealment image 42 made of coloring. Since it is the same as 1, the same symbol is given to the same component, and the explanation is omitted.

  As in the first embodiment, the watermark main image 11 of the watermark mark unit 32 is configured by the printing unit 5 in which light-shielding ink is solidly applied. On the other hand, as shown in FIG. 7, the watermark concealment image 42 is formed so that the ultrafine line with a width of 200 μm constituting the coloring is drawn by printing application of light-shielding ink and is adjacent to the watermark main image 11. . The watermark concealment image 42 can be seen by the difference in transmittance between the ultrathin line drawn with the light-shielding ink and the surrounding non-printing portion 6, and the ultrathin line is a very thin line having a width of 200 μm. Therefore, it cannot be visually recognized only by seeing through the watermark (see FIG. 8B). Furthermore, in the configuration of the second embodiment, similarly to the first embodiment described above, the watermark main image 11 is formed by solid coating of light-shielding ink, and the boundary with the surrounding non-printing portion 6 is clear. When viewed through a watermark, the watermark main image 11 can be clearly seen, but the watermark concealment image 42 adjacent to the periphery of the watermark main image 11 is not conspicuous, and the effect of concealing the presence of the watermark concealment image 42 is high.

  Even in the watermark concealment image 42 of the second embodiment, it can be clearly seen as shown in FIG. 8B by observing with a UV illumination type optical microscope, as in the first embodiment. And with a general optical microscope using visible light, it is not clearly visible. Therefore, even in the watermark concealment image 42 of the second embodiment, the visual recognition method is limited and the concealment is extremely high.

  The counterfeit prevention form 31 according to the second embodiment can clearly see the watermark main image 11 by viewing it through light. Therefore, as in the first embodiment described above, authenticity can be determined based on the presence or absence of the watermark main image 11 by using it for securities or certificates.

  Furthermore, since the watermark concealment image 42 of the watermark mark portion 32 is composed of coloring drawn with ultrathin lines, it can be viewed through light and a general optical microscope using visible light. A special microscope such as a UV illumination type optical microscope or an electron microscope is required in order to clearly see the image without using the lens. Therefore, even in the watermark concealment image 42 of the second embodiment, as in the first embodiment, the secrecy is extremely high and the accuracy of authenticity determination can be remarkably improved, so that the effect of preventing forgery is also high.

Even in the forgery prevention form 31 of the second embodiment, it can be similarly manufactured using the manufacturing method in the first embodiment described above.
That is, in the watermark printing step of the first printing step, the plate roller 52 that can print the watermark main image 11 and the watermark concealment image 42 at a time is used (see FIG. 4). Here, the printing plate 57 of the plate roller 52 is formed with a convex portion forming the shape of the watermark main image 11 and a convex portion forming the ultrathin line constituting the watermark concealment image 42. The amount of light-shielding ink attached to the printing plate 57 of the plate roller 52 is appropriately set so that the fine line of the watermark concealment image 42 can be printed with high accuracy. In addition, this adhesion amount is appropriately set according to the line width of the extra fine wire. In the watermark printing process, as in Example 1 described above, a light-shielding ink is attached from the ink roller 54 to the convex portion of the printing plate 57, and the printing plate 57 of the plate roller 52 is pressed against the surface of the base paper 10, The light-shielding ink is transferred onto the surface of the base paper 10, and the watermark main image 11 and the watermark concealment image 42 composed of the fine lines are printed.

  After such a watermark printing step, a drying step of irradiating with ultraviolet light is executed (not shown) as in the first embodiment. Through this drying process, the light-shielding ink transferred to the surface of the base paper 10 is fixed. In the method for manufacturing the forgery prevention form 31 according to the second embodiment, the printing plate of the plate roller 52 used in the watermark printing process is matched with the watermark mark portion 32. Since it is the same, the details are omitted as appropriate.

  In the manufacturing method described above, the watermark main image 11 and the watermark concealment image 42 can be printed at one time by one printing plate (plate roller 52) in the watermark printing step. Time required and labor can be suppressed as much as possible. The watermark mark portion 32 can be printed with high accuracy and the productivity is high.

In this invention, it is not limited to the Example mentioned above, About the structure other than the above-mentioned Example, it can change and implement suitably within the range of the meaning of this invention.
For example, in the first embodiment, the micro characters constituting the watermark concealment image may be drawn with light-shielding ink at a position adjacent to the watermark main image 11. Further, in the second embodiment, the coloring that constitutes the watermark concealment image may be formed inside the watermark main image 11 as a white image without applying light-shielding ink.
In the first and second embodiments, only one of the micro-character watermark concealment image and the chromatic sentence watermark concealment image is provided. It is good also as a structure provided with the watermark concealment image.
Further, in Examples 1 and 2, the printing part is formed by solid coating of light shielding ink, but as another configuration, the printing part can be formed by halftone dots or lines, The gradation may be expressed by the halftone dots or lines.
On the other hand, in the manufacturing methods of the first and second embodiments, the plate roller is used in the watermark printing process. However, the present invention is not limited to this, and a flat plate may be pressed against the surface of the base paper.

1 Anti-counterfeiting document 2,32 Watermark mark part 5 Printing part 6 Non-printing part 10 Base paper (sheet-like substrate)
11 Watermark main image 12, 42 Watermark hidden image 57 Print version

Claims (5)

On the surface of a sheet-like substrate, a watermark mark portion is formed in which the transmissivity differs between a printed portion printed with paper-colored light-shielding ink containing titanium oxide as a white pigment and a non-printed portion not printed. It is made up,
The watermark mark part is:
A watermark main image that is visible by light transmission;
An anti-counterfeit form, comprising: a watermark concealment image that is less visible due to the transmission of light than the watermark main image.   The forgery prevention form according to claim 1, wherein the watermark concealment image is composed of one or a plurality of micro characters having a character size of 100 µm or more and 1000 µm or less.   2. The forgery prevention form according to claim 1, wherein the watermark concealment image is composed of coloring drawn with a fine line having a width of 200 [mu] m or less.   The anti-counterfeit form according to any one of claims 1 to 3, wherein the light-shielding ink has a titanium oxide content of 30% or more and 70% or less. A method for manufacturing a forgery prevention form according to any one of claims 1 to 4,
A method for producing a forgery-preventing form, comprising: a printing step of printing a watermark mark portion with a single printing plate for printing a watermark main image and a watermark concealment image.

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