JP5828184B2 - Latent image printed matter - Google Patents

Description

  The present invention relates to a latent image printed matter. In particular, in the field of valuable printed matter such as banknotes, passports, securities, identification cards, cards, and passports that are security printed matter that requires anti-counterfeiting effects, images that can be observed under visible light have a specific wavelength band. This is related to a special image line structure that changes to a completely different image when observed with the light of the above, and a latent image printed matter that can be formed thereby.

  With recent developments in digital devices such as scanners, printers, and color copiers, it has become possible to easily produce elaborate copies of precious printed matter. Therefore, in order to prevent duplication and forgery as described above, various anti-counterfeit technologies that are not reproducible by simple copying, such as squeeze, are required. Among such anti-counterfeiting technologies is a technology that consists of a combination of a complex image line configuration and various functional inks with special functions, and a visible image that is visible under visible light, and a specific A technology having a so-called image change effect in which a latent image visually recognized under the above conditions is a different image having no correlation is known as a conventional technology.

  The present applicant uses two inks as a pair ink that are observed in the same color under visible light, but are observed in different colors under light in a specific wavelength band, and have a special halftone dot. It is a printed matter configured according to the configuration, and has an image change effect in which an image viewed under visible light and an image viewed with light in a specific wavelength band are different images that have no correlation at all. An invention relating to a latent image printed material characterized by the above has already been filed (see, for example, Patent Document 1 and Patent Document 2).

  In addition, the present applicant is a printed matter having two patterns composed of a plurality of regularly arranged lines, a first pattern printed with a material that does not absorb or excite at a specific wavelength, and a specific pattern. The second pattern printed with a material that absorbs or excites at the wavelength is configured by changing the image line width or the arrangement of the image lines, and the image line forming the second pattern configures the first pattern. The anti-counterfeit printed matter is arranged so as to overlap the image line of the image line, and the first pattern is visually recognized under observation under visible light, and the first pattern is observed under light under a specific wavelength band. An invention relating to a latent image printed matter having a so-called image change effect in which the pattern 2 is visually recognized has already been filed (see, for example, Patent Document 3).

  Also, a printed line in which a line is composed of a latent image portion and a non-latent image portion having a width of approximately 1: 1, and the line is a latent image portion and a non-latent image object, and the phase is shifted by 1/2 pitch, When a line film having a line pattern of the same shape as the line is superimposed, the non-latent image part is hidden by the line pattern of this line film and only the latent image part appears as an image is filed (For example, refer to Patent Document 4).

Japanese Patent No. 3544536 Japanese Patent No. 4395598 Japanese Patent No. 4512789 JP 2001-213042 A

  However, with respect to the technologies described in Patent Documents 1 and 2 of the prior art, both the visible image and the latent image can form an image with high contrast and rich gradation expression, but the paired inks used must be of the same color. Therefore, it was necessary to perform strict color matching during ink production. In addition, since the two images that make up the printed material do not have overlapping areas and are completely next to each other, so-called `` tweeping '', the most difficult printing composition that does not allow slight deviation, There is a problem that extremely high technology is necessary for continuous production.

  In addition, regarding the technique described in Patent Document 3, it is necessary to superimpose different lines on one image line, and as in the techniques described in Patent Document 1 and Patent Document 2, high-precision printing is performed in manufacturing. It was something that demanded. In addition, when the present technology is configured using a material having a certain color density, such as an infrared absorbing material, the density of the region where the image line is superimposed partially increases and is originally visually recognized. There existed a subject that the 2nd pattern which should not be visually recognized.

  Although the technology described in Patent Document 4 is easy to form, it was effective technology for counterfeiting and duplication prevention at the time of development. However, since it does not have the counterfeit resistance necessary for the authenticity discrimination technique, it cannot function as a reference for authenticity determination.

  An object of the present invention is to solve such a conventional problem, and is a printed matter having a structure in which a latent image is concealed in a visible image by shading caused by interference between two image lines, and has a high degree of printing. The image that can be manufactured at low cost without the need for color matching or strict ink color matching, and the image that is visible under visible light and the image that is visible under light in a specific wavelength band are completely correlated. The present invention provides a latent image printed material having a so-called change effect, which is a different image.

In order to solve the above-mentioned problem, the invention according to claim 1 of the present invention has a printed image having a color different from that of the substrate on at least a part of the substrate,
The printed image is formed by superimposing a first image and a second image,
The first image has a plurality of first image lines that are sequentially arranged at a specific pitch in a specific direction with a first ink,
The second image has a plurality of second image lines that are continuously arranged at the same pitch as the specific pitch in the same direction as the specific direction with the second ink,
i) The first image has first significant information formed by shifting a part of the first image line in a phase in the specific direction, or
ii) the second image has first significant information formed by shifting a part of the second image line in a phase in the specific direction;
The first drawing line is configured such that the background drawing line and the information drawing line do not overlap,
The first image has second significant information formed by the information image line constituting the first image line,
The hues of the first ink and the second ink are close, and the color density of the first image line under visible light is lighter than the color density of the second image line under visible light,
The first image line has a higher color density than the second image line under light of a specific wavelength band,
When observed under visible light, first significant information is visible in the printed image, and when observed under light of the specific wavelength band, second significant information is present in the printed image. Is a latent image printed matter characterized by being visible.

In the invention according to claim 2 of the present invention, the shift between the pitch of the first image line and the pitch of the second image line is in the range of 90% to 110% on the basis of the case where the first image line completely matches, The latent image printed matter according to claim 1, wherein a difference between the line angles of the first image line and the second image line is within 3 degrees.

In the invention according to claim 3 of the present invention, the difference in the line area ratio between the background image line and the information image line is 5% or more and 40% or less, and the background image line and the second image line The latent image printed matter according to claim 1 or 2, wherein the image area ratio is in the range of 20% to 80% .

According to a fourth aspect of the present invention, the plurality of background image lines constituting the first image, the plurality of information image lines constituting the first image, and the plurality constituting the second image. The latent image printed matter according to claim 1, wherein the total area ratio of the second image lines is 100% or more and 180% or less.

Since this invention is the above structure, there exists an effect as shown below.
That is, unlike the prior art, the latent image printed matter of the present invention is visualized by the shading generated by the interference between two image lines, and the printing is shifted from the normal position. However, if the misalignment is within a certain range, the change in the density difference remains in a very small range. The second significant information can be easily concealed visually because it is camouflaged by the resulting shading. Therefore, in order to realize the effect of changing the image according to the change of the observation method as in the prior art, strict printing accuracy is not required and the manufacturing is extremely easy.

  Further, unlike the prior art, the latent image print of the present invention does not require the two paired inks to be of the same color, the second ink has a hue close to the first ink, and the second ink It should be darker than the first ink. This is because the labor of color matching at the time of ink design can be remarkably reduced, and since there are many combinations of such first ink and second ink, the degree of freedom of color selection in the design is expanded. There is.

  Latent image printed matter formed by the above method is excellent in cost performance because it can be manufactured by offset printing, which is a highly productive printing method, and it is not possible to achieve a change effect even with the latest digital equipment. Since it is possible, it has an excellent anti-counterfeit effect. In addition, since both the information element and the latent image element have high visibility, it is easy to distinguish between a genuine product and a counterfeit product, and the practical effect of being excellent in authenticity discrimination performance is exhibited.

It is a top view which shows the latent image printed matter in embodiment of this invention. It is the schematic which shows the structure of the latent image printed matter in embodiment of this invention. It is the schematic which shows the structure of the 1st image in embodiment of this invention. It is the schematic which shows the structure of the 2nd image in embodiment of this invention. It is the schematic which shows the positional relationship of the overlap of the 1st image and 2nd image in embodiment of this invention. It is a figure which shows the effect in one Example of this invention. It is a top view which shows the latent image printed matter in one Example of this invention. It is the schematic which shows the structure of the latent image printed matter in one Example of this invention. It is the schematic which shows the structure of the 1st image in one Example of this invention. It is the schematic which shows the structure of the 2nd image in one Example of this invention. It is the schematic which shows the positional relationship of the overlap of the 1st image and 2nd image in one Example of this invention. It is a figure which shows the effect in one Example of this invention. It is a top view which shows the latent image printed matter in one Example of this invention. It is the schematic which shows the structure of the latent image printed matter in one Example of this invention. It is the schematic which shows the structure of the 1st image in one Example of this invention. It is the schematic which shows the structure of the 2nd image in one Example of this invention. It is a figure which shows the spectral reflection characteristic of the pair ink in one Example of this invention. It is the schematic which shows the positional relationship of the overlap of the 1st image and 2nd image in one Example of this invention. It is a figure which shows the effect in one Example of this invention. It is a top view which shows the latent image printed matter in one Example of this invention. It is the schematic which shows the structure of the latent image printed matter in one Example of this invention. It is the schematic which shows the structure of the 1st image in one Example of this invention. It is the schematic which shows the structure of the 2nd image in one Example of this invention. It is the schematic which shows the positional relationship of the overlap of the 1st image and 2nd image in one Example of this invention. It is a figure which shows the effect in one Example of this invention.

  Embodiments for carrying out the present invention will be described with reference to the drawings. However, the present invention is not limited to the modes for carrying out the invention described below, and various other embodiments are included within the scope of the technology described in the claims.

  FIG. 1 shows a latent image printed material (1) according to the present invention. The latent image printed matter (1) is formed by forming a printed image (3) having a color different from that of the substrate on at least a part of the substrate (2). For convenience of explanation, the characters “NPB” are shown in the print image (3), but the characters “NPB” are actually invisible under visible light, and only the characters “NIPPON” are visualized. ing.

  FIG. 2 shows the configuration of the print image (3). The print image (3) includes a first image (4) and a second image (5), and both the first image (4) and the second image (5) are different from the base material (2). Need to have color.

  FIG. 3 shows a first image (4) and an enlarged view of a part thereof. The first image (4) is formed by continuously arranging the first image line (6) having the image line width W1 at a pitch P1 in a specific direction (direction S1 in the drawing). Further, a region (7) having a different image area ratio is provided in a part of the first image line (6), and the letters “NPB” of the alphabet as the second significant information are formed. Hereinafter, among the first drawing lines, the drawing line forming a flat background other than the second significant information indicated by the drawing line including the vertical line is defined as the background drawing line (6). Among the lines, an image line forming the second significant information indicated by a square pixel is defined as an information image line (7). In the present embodiment, the information image line (7) is assigned to the upper and lower positions adjacent to the background image line (6), and the region having the image line width W2 slightly thicker than the image line width W1 is provided. Although the second significant information is formed, the second significant information may be formed by any method as long as the method is a method of forming the shade by the difference in the area ratio.

  The “image line” used in the present specification is an image element formed by continuously arranging halftone dots, which are the minimum units for forming the print image (3), in a certain direction for a certain distance without a gap. It is a dotted line, a broken line, a straight line, a curved line, or a wavy line, and any image line shape is included in the technical idea of the present invention. Further, the “line area ratio” used in the present invention refers to the ratio of the area of the line to a certain area.

  FIG. 4 shows a second image (5) and an enlarged view of a part thereof. The second image (5) is formed by continuously arranging the second image lines (8A, 8B) having the image line width W3 at a pitch P1 in a specific direction (direction S1 in the drawing). A part of the line (8A) is provided with a region (8B) having a different phase in a specific direction (S1 direction in the figure), and the letters “NIPPON” of the alphabet as the first significant information are formed.

  FIG. 5 shows the positional relationship of the overlap between the first image (4) and the second image (5). The positional relationship on the layer structure of the first image (4) and the second image (5) may be either the upper layer or the lower layer, and it is only necessary to maintain a positional relationship in which the images overlap each other. As shown in FIG. 5, the most appropriate positional relationship is that the center of the image line of the background image line (6) in the S1 direction and one of the image lines of the two second image lines (8A, 8B). It is only necessary to have a positional relationship in which the center of the image line completely coincides, and the image line widths (w1) and (w3) shown in FIGS. 3 and 4 may be different. In this case, the first significant information visualized by interference appears with the highest contrast in the negative or positive.

  In the case of the positional relationship shown in FIG. 5, the first significant information appears in a positive state with the highest contrast. Further, when the positional relationship of the overlap between the first image (4) and the second image (5) deviates from this positional relationship by half of the pitch P1, the first significant information has the highest contrast and is negative. Appears in the state of. Further, when the positional relationship of the overlap between the first image (4) and the second image (5) is shifted by one pitch (P1) from the positional relationship of FIG. Appears in the positive state with the same highest contrast as 5. When the positional relationship of the overlap between the first image (4) and the second image (5) is as described above, the first significant information is visualized with the highest contrast.

  On the contrary, the contrast of the first significant information is the lowest because the first image (4) and the second image are separated by a distance of 1/4 and 3/4 of the pitch (P1) from the positional relationship of FIG. This is a case where the positional relationship of the overlap of the image (5) is shifted. Since the present invention uses the fact that contrast is caused by the phenomenon of interference, in this case, the first significant information visualized by the interference becomes invisible, and conversely the second significant information becomes Therefore, the image change effect of the present invention is lost. Accordingly, the positional relationship of the overlap between the first image (4) and the second image (5) is shifted from the positional relationship of FIG. 5 by a distance of 1/4 and 3/4 of the pitch (P1). It is not preferable to become.

  As described above, when the second significant information is formed in the range of the appropriate line area ratio, and the background line (6) and the second line (8) are formed in the range of the desired area ratio. Even if the printing is misaligned, if the displacement is not a quarter distance or a third distance of the pitch (P1) in a specific direction (direction S1 in the figure), the first Since significant information is visualized, the change effect of the present invention can be secured.

  The first image (4) is formed with the first ink, and the second image (5) is formed with the second ink. In the observation under visible light, the first ink and the second ink do not have to be the same color as in the conventional technique, and the hues only need to be close. As used herein, “close hue” means that the hues must not be extremely different, such as red and green, but are arranged in the order of the longest wavelength of light, such as blue and green, yellow and orange. Of the seven hues of red, orange, yellow, green, blue, and indigo, the hues are close to each other.

  The color density of the first image line under visible light needs to be less than or equal to the color density of the second image line under visible light. That is, the color density under visible light is lighter for the first image line than for the second image line. This is because when the first image line is darker than the second image line, the second significant information is reflected in the first significant information in the observation under visible light, resulting in an unclear image. This is to avoid that. The “color density” used in the present specification is a color density measurement value when measured with a densitometer such as a Gretag densitometer (manufactured by Gretag Macbeth), and colors of cyan, magenta, yellow, and black. Of the densities (Dc, Dm, Dy, Dk), the color density of the main component showing the highest value is indicated.

  On the other hand, in observation under light of a specific wavelength band, the first image line formed with the first ink is visually recognized as being darker than the second image line formed with the second ink. It is necessary to have. As used herein, the phrase “observation under a specific wavelength band” refers to observing a printed material with light in a wavelength band other than visible light such as infrared or ultraviolet, or blue, green or red. It refers to a state where observation is performed only with light in a specific wavelength band in visible light. In addition, it may be either used by irradiating the printed material with light of the specific wavelength band, or when receiving reflected light generated from the printed material. For example, an image may be acquired with visible light using ultraviolet light as irradiation light, or an image may be acquired with infrared light by making visible light incident.

  As an example, when a specific wavelength band is infrared, a material that absorbs infrared light may be used for the first ink, and a material that does not absorb infrared light may be used for the second ink. An ultraviolet-excited luminescent material may be used for the first ink, and a material that is not excited by ultraviolet rays may be used for the second ink. Not absorbing infrared rays includes transmission and reflection.

  FIG. 6 shows the effect of the latent image print (1) of the present invention. FIG. 6A shows an image that can be observed in the printed image (3) when the latent image print (1) of the present invention is observed under visible light. Note that the term “observation under visible light” used in the present specification specifically refers to the light (9) emitted from the light source (9) and the printed matter (1), as shown in FIG. So-called diffusely reflected light is relatively different from the angle (incidence angle) formed and the angle (reflection angle) formed by the reflected light from the printed matter (1) and reaching the viewer's viewpoint (10) with the printed matter (1). It is an observation under a large number of environments, and the light applied to the printed material has a wavelength of visible light from 400 nm to 700 nm.

  In the observation under visible light shown in FIG. 6A, the letter “NIPPON” as the first significant information in the printed image (3) is positive (11A) or negative (11B). Appear. As used in this specification, “positive” refers to a state in which significant information is dark and the surrounding background is light, and one “negative” is a state in which significant information is light and the surrounding background is dark. Point to.

  At this time, whether the first significant information appears positively or negatively is determined by the positional relationship of the overlap between the first image (4) and the second image (5). Specifically, taking the image line configuration of the present embodiment as an example, if the background image line (6) overlaps the second image line (8A) representing the background around the first significant information, One significant information is visualized in a positive (11A) state, and when it is superimposed on a second image line (8B) representing the first significant information, the first significant information becomes a negative (11B) state. Visualized.

  On the other hand, in observation with light of a specific wavelength band, the letters “NPB” of the alphabet, which is the second significant information, appear in the printed image (3). The characteristics required for the first ink and the second ink vary depending on which range the wavelength band of light used for observation is set. If the wavelength of light used for observation is in the infrared region, the first ink may contain a material that absorbs infrared light, and the second ink may not contain this. In that case, the authentication device (12) shown in FIG. 6 (b) becomes an infrared viewer, and when this infrared viewer is used, as shown in FIG. 6 (b), the first ink formed with the first ink is used. Only the image (4) is visible.

  The principle that only the first image (4) can be observed in the observation of light in a specific wavelength band will be described. The letters “NIPPON”, which is the first significant information that has been visually recognized by observation under visible light, are information that has been visualized by the interference of two drawing lines. However, when observing with light of a specific wavelength band, one of the two lines is invisible or one of the two lines causing interference because the contrast is reduced. As a result of disappearance, the phenomenon of interference itself is lost, and the shading formed by the interference disappears or becomes extremely small. Therefore, the first significant information becomes invisible, and the first image (4) that has been concealed visually appears in the shading caused by the interference until then.

  In the conventional technology having an image change effect, the density of the visible image (second significant information of the present invention) is generally constituted by the difference in the area ratio created by the second ink. Yes, whether or not the visible image disappears in observation with light of a specific wavelength band largely depends on the optical characteristics of the second ink used. That is, if the second ink does not absorb light in a specific wavelength band, the visible image disappears well, but if it absorbs even a small amount of light in the specific wavelength band, the visible image becomes difficult to disappear. In particular, whether or not a visible image formed with a high density (high area ratio) can be lost under light of a specific wavelength band depends on the optical characteristics of the second ink. Therefore, in the prior art, whether or not the second ink having the desired optical characteristics can be found is extremely important.

  However, in the present invention, the visible image observed under visible light is an image caused by interference, and there is no need to create a shade of the visible image by providing a difference in area ratio using the second ink. That is, since the second image (5) of the present invention itself is a flat image having no contrast, it is visually compared with an image having a contrast as in the conventional art. The disappearance effect of is much higher. Therefore, even when it is formed using a second ink that has only optical properties that have been determined not to have the desired performance, visible images can be easily lost in observation under specific conditions. be able to. This is one of the great advantages of the present technology over the conventional technology having the same effect.

  In the present invention, it is most preferable that the pitch of the first image (4) and the second image (5) is the same pitch (P1). In the printed matter to be manufactured, the pitch may not completely match. In this case, moiré occurs in the image due to the deviation of the pitch of the two image lines. Although such moiré affects the visibility of the first significant information, the first significant information can be visually recognized. Since the first image (4) and the second image (5) are slightly shifted in pitch, the configuration of the present invention is also included. In addition, in order to actively control such difficult situations that occur at actual manufacturing sites, the pitch of the two images is slightly shifted in advance at the stage of the drawing line design, or the angle between the two drawing lines is set. There is a case where a slightly deliberate design in which moire is generated is used. Such a configuration is also included in the scope of the configuration of the present invention. Specifically, the desired pitch deviation that is intentionally formed is based on the pitch (P1) that is the pitch of the first image (4) or the pitch of the second image (5). The value in the case of 100% is 100% ± 10%, that is, a range of 90% to 110%, and it is desirable to keep the difference in the angle of view within 3 degrees. If it is out of this range, it depends on the printing area, but the change in shading due to moire becomes too large, or the pitch of the moire becomes finer, and the influence on the visibility of the first significant information becomes large. It is desirable.

  The area ratio of the second significant information formed in the first image (4) depends on the coloring power of the two inks used, but a coloring material having a strong coloring power such as black or wrinkle was used. Even in this case, it is necessary to design the first image (4) such that the difference from the area ratio of the background around the second significant information is 5% or more and 40% or less. When formed with an area ratio of less than 5%, it is difficult to visually recognize when observed with light of a specific wavelength band, and when the second significant information is formed with an area ratio of more than 40%, This is because it is impossible to completely conceal the second significant information in observation under visible light.

  The area ratio of the first image (4) and the second image (5) excluding the region where the second significant information is formed is most preferably designed within a range of plus or minus 30% centering on 50%. desirable. This means that if either image is completely solid with a dot area ratio of 100% (the printed surface has no difference in density or white areas and the entire surface is filled) or nothing is printed, When two images are formed by a group of non-image lines and when the two images are superimposed, interference occurs, but in the overlap of image areas with an area ratio of less than 20% or more than 80%, The entire image is too dark or too light, and the density tends to be biased. The contrast between the first significant information and the surrounding background does not occur, and the first significant information is visible. This is because of a decrease.

  Further, since the visible image of the latent image printed material (1) of the present invention is visualized by interference, the total area ratio of the first image (4) and the second image (5) is also important. The total area ratio of the first image (4) and the second image (5) is preferably 100% or more and 180% or less. The total area ratio of the first image (4) and the second image (5) is the same as the area ratio of the first image (4) excluding the area where the second significant information is formed. Is the total value of the three area ratios of the area ratio of the first image and the area ratio of the second image (5). Among these, the area ratio of the first image (4) and the second image excluding the region where the second significant information is formed is 80% at the maximum as described above, and the second significant information is formed. Since the difference with the area ratio of the surrounding background is 5% or more and 40%, the region thus obtained can be up to 40% (80% -40%). The maximum value of all of these is 80% + 80% + 40% = 200%. However, since the second significant information needs to be formed in the first image, the region where the second significant information is formed. The total area ratio of the area ratio of the first image (4) excluding the area ratio of the first image in the area where the second significant information is formed cannot exceed 100%. Therefore, the maximum area ratio of the first image is 100%, and when the maximum area ratio of the second image is 80%, the maximum area ratio is 180%. The higher the total area ratio, the higher the concealability of the second significant information. On the other hand, the first significant information becomes darker and the contrast is lowered, so that the first image (4) according to the design. It is necessary to adjust the area ratio of the second image (5).

  Further, the first ink and the second ink may be provided with functionality other than that the contrast is different under light of a specific wavelength band. For example, characteristics such as a thermochromic material, a photochromic material, or the like that changes in color depending on temperature or the amount of light to be irradiated, or a characteristic that strongly reflects light like a glittering material may be added. In these cases, it is possible to add an effect that the entire image changes due to temperature change or light change, or that only the first image (4) appears.

  The printing method of the latent image printed material in the present invention can be formed by any printing method such as offset printing, flexographic printing, letterpress printing, gravure printing, screen printing, intaglio printing. Further, if functional ink can be used, it can be formed by IJP or the like. In this case, so-called variable printing can be performed in which information on one output item is changed.

  The substrate constituting the latent image printed matter of the present invention is selected depending on the product and the like, for example, polyethylene terephthalate (PET) used for securities papers and cards including fine paper used for banknotes, securities, etc. However, it is not limited to these.

  Hereinafter, examples of the latent image printed matter produced specifically will be described in detail according to the best mode for carrying out the invention described above, but the present invention is not limited to these examples.

  A first embodiment of the present invention will be described with reference to FIGS. The first embodiment is an example in which light of a specific wavelength band used for authentication of second significant information is infrared. FIG. 7 is a diagram illustrating the latent image printed matter (1-1). The latent image print (1-1) is formed by forming a print image (3-1) on a base material (2-1). In Example 1, white high quality paper (manufactured by Nippon Paper Industries Co., Ltd.) was used for the base material (2-1).

  FIG. 8 shows two images included in the print image (3-1). The printed image has a dark black color and includes a first image (4-1) that is dark black and a second image (5-1) that is slightly bluish black. For convenience of explanation, the characters “NPB” are represented in the print image (3-1). However, in actuality, the characters “NPB” are invisible under visible light, and the characters “NIPPON” are displayed. Only is visible.

  FIG. 9 shows a first image (4-1) and an enlarged view of a part thereof. The first image (4-1) is formed by continuously arranging first image lines (6-1) having an image line width of 0.2 mm at a pitch of 0.4 mm in the S1 direction. In the present embodiment, a region (7-1) having a different image area ratio is provided in the first image (4-1), and the letters “NPB” of the alphabet, which is the second significant information, are provided. Formed. In this example, unlike the first embodiment, in addition to the first image line (6-1), the second significant information is set to 0 so that it does not overlap the first image line (6-1). A first image line (7-1) having an image line width of .08 mm was continuously arranged in the S1 direction at a pitch of 0.4 mm at a position not overlapping the first image line (6-1). Hereinafter, the first image line (6-1) having a line width of 0.2 mm is set as the background image line (6-1), and another image line width of 0.08 mm forming the second significant information is set. One image line (7-1) will be described as an information image line (7-1). The information image line (7-1) is arranged at a position not overlapping the background image line (6-1) in the first image (4-1), so that the first image (4-1) ) To create a shade based on the difference in area ratio and visualize the second significant information. This first image was printed on a substrate (2-1) by a wet offset printing method using a black ink containing carbon black which is an infrared absorbing material.

  FIG. 10 shows a second image (5-1) and an enlarged view of a part thereof. The second image (5-1) is formed by continuously arranging second image lines (8A-1, 8B-1) having an image line width of 0.3 mm at a pitch of 0.4 mm in the S1 direction, In addition, in the second image (5-1), a part of the second image line (8A-1) is shifted by 0.2 mm in the S1 direction, and regions (8B -1) is provided, and the letters “NIPPON” of the alphabet as the first significant information are formed. This second image is overlaid on the first image (4-1) by wet offset printing using a bluish, slightly dark black ink containing chromofine black as a main component, which does not contain an infrared absorbing material. Printed together.

  FIG. 11 shows the positional relationship of the overlap between the first image (4-1) and the second image (5-1). In this embodiment, the center of the image line of the background image (6-1) of the first image (4-1) and the second image line (8A-1) of the second image (5-1). The images were overlaid with a positional relationship where the image line centers coincided.

  The latent image printed matter (1-1) of Example 1 was formed with the above configuration. The effect of the latent image printed matter of this embodiment will be described with reference to FIG. FIG. 12A shows an image that can be visually recognized in the printed image (3-1) when the latent image printed matter (1-1) of this embodiment is observed under visible light. In the observation under visible light shown in FIG. 12 (a), the letter “NIPPON” of the alphabet, which is the first significant information, is black positive (11A-1) in the printed image (3-1). Appeared in. If the phase of printing is shifted by 0.2 mm in the S1 direction from the positional relationship shown in FIG. 11, the letter “NIPPON”, which is the first significant information, is negative (11B-1). ).

  On the other hand, when an infrared viewer (12-1) is used as an authentication device and observed with infrared rays, as shown in FIG. 12 (b), only the first image (4-1) formed with the first ink is present. That is, the letters “NPB” of the alphabet, which is the second significant information, were visible.

  As described above, the first significant information can be visually recognized in the observation with visible light, and the second significant information can be visually recognized in the observation with one infrared ray. The effect of changing the image in the printed image (3-1) according to the observation conditions could be confirmed.

  A second embodiment of the present invention will be described with reference to FIGS. The second embodiment is an example in which light of a specific wavelength band is red light. FIG. 13 shows the latent image printed material (1-2). The latent image print (1-2) is formed by forming a print image (3-2) on a substrate (2-2). In this example, white fine paper (manufactured by Nippon Paper Industries Co., Ltd.) was used as the base material (2-2).

  FIG. 14 shows two images included in the print image (3-2). The printed image has a brown color and includes a first image (4-2) that is light brown and a second image (5-2) that is dark brown. For convenience of explanation, the characters “NPB” are represented in the print image (3-2), but the characters “NPB” are actually invisible under visible light, and only the characters “NIPPON” are displayed. Is visualized.

  FIG. 15 shows a first image (4-2) and an enlarged view of a part thereof. In the second embodiment, unlike the above-described embodiment and the first embodiment, not only the second significant information but also the first significant information is simultaneously formed in the first image (4-2). It consists of

  First, the first image (4-2) has two first image lines (6A-2, 6B-2) having an image line width of 0.2 mm. The two first image lines (6A-2, 6B-2) are continuously arranged at a pitch of 0.4 mm in the S1 direction. One first image line (6A-2) and the other first image line (6B-2) are shifted by 0.2 mm in the S1 direction. The first image line (6B-2) Is formed by forming the letters “NIPPON” of the alphabet as the first significant information.

  In this first image (4-2), regions (7A-2, 7B-2) having different image area ratios are provided in part of the first image lines (6A-2, 6B-2). The letters “NPB”, which is the second significant information, are formed. In the second embodiment, the second significant information is not overlapped with the first image line (6A-2, 6B-2) separately from the first image line (6A-2, 6B-2). A position where the first image line (7A-2, 7B-2) having an image line width of 0.06 mm does not overlap the first image line (6A-2, 6B-2) at a pitch of 0.4 mm in the S1 direction. And arranged continuously. Hereinafter, the first image line (6A-2, 6B-2) having an image line width of 0.2 mm is set as the background image line (6A-2, 6B-2), and 0.06 mm forming the second significant information. The other first image lines (7A-2, 7B-2) of the image line width will be described as information image lines (7A-2, 7B-2). The information image line (7A-2, 7B-2) is arranged at a position that does not overlap with the background image line (6A-2, 6B-2) in the first image (4-2). The first image (4-2) is created by creating shading due to the difference in area ratio and visualizing the second significant information. This first image was formed by a wet offset printing method using a light brown metameric pair ink A having a remarkable light absorption characteristic at a wavelength of 660 nm to 700 nm.

  FIG. 16 shows a second image (5-2) and an enlarged view of a part thereof. The second image (5-2) is formed by continuously arranging second image lines (8-2) having an image line width of 0.3 mm in the S1 direction at a pitch of 0.4 mm. This second image is overlaid on the first image (4-2) by wet offset printing method using dark brown metameric pair ink B, which has no light absorption characteristics at wavelengths of 660 nm to 700 nm. Printed together. For reference, spectral reflectances of the metameric pair ink A and the metameric pair ink B are shown in FIG. The spectral reflectance of the metameric pair ink A is shown in a graph 13-2, and the spectral reflectance of the metameric pair ink B is shown in a graph 14-2. The two inks have substantially the same spectral reflectance from 400 nm to 600 nm, but the reflectance of light in the wavelength band of 600 nm to 700 nm is greatly different.

  FIG. 18 shows the positional relationship of the overlap between the first image (4-2) and the second image (5-2). In Example 2, the image line center of the first image line (6B-2) and the image line center of the second image line (8-2) were overlapped with each other.

  With the above configuration, the latent image printed material (1-2) of Example 2 was formed. The effect of the latent image printed matter of Example 2 will be described with reference to FIG. FIG. 19A shows an image that can be visually recognized in the printed image (3-2) when the latent image printed material (1-2) of Example 2 is observed under visible light. In the observation under visible light shown in FIG. 19A, the letter “NIPPON” of the alphabet which is the first significant information in the printed image (3-2) is a light brown negative (11B-2). Appeared in state. If the printing phase is shifted by 0.2 mm in the S1 direction from the positional relationship shown in FIG. 18, the letter “NIPPON” of the alphabet, which is the first significant information, is a dark brown positive ( It appears in the state of 11A-2).

  On the other hand, as the authentication device, a filter (SC66 manufactured by Fuji Film) (12-2) that transmits only light having a wavelength of 660 nm to 700 nm was used, and the latent image printed material (1-2) was observed with light having a red wavelength. In this case, as shown in FIG. 19B, only the first image (4-2) formed with the first ink, that is, the letters “NPB” of the alphabet as the second significant information can be visually recognized. It was.

  As described above, the first significant information can be visually recognized in the observation with visible light, and the second significant information can be visually recognized in the observation with one red light. The effect of changing the image in the printed image (3-2) according to the observation conditions could be confirmed.

  A third embodiment of the present invention will be described with reference to FIGS. As in the first embodiment, the third embodiment is an example in which light of a specific wavelength band is infrared, and the first significant information forming method is slightly different from the previous examples. FIG. 20 shows the latent image print (1-3). The latent image print (1-3) is formed by forming a print image (3-3) on a base material (2-3). In this example, white fine paper (manufactured by Nippon Paper Industries Co., Ltd.) was used as the base material (2-3).

  FIG. 21 shows two images included in the print image (3-3). The printed image (3-3) has a dark black color, and includes a first image (4-3) that is dark black and a second image (5-3) that is slightly bluish black. It consists of For convenience of explanation, the characters “NPB” are shown in the print image (3-3). However, the characters “NPB” are actually invisible under visible light, and only the characters “NIPPON” are displayed. Is visualized.

  FIG. 22 shows a first image (4-3) and an enlarged view of a part thereof. The first image (4-3) is formed by continuously arranging first image lines (6-3) having an image line width of 0.2 mm at a pitch of 0.4 mm in the S1 direction. In the first image (4-3), a region (7-3) having a different line area ratio is provided, and letters “NPB” of the alphabet as the second significant information are formed. In the third embodiment, as in the first embodiment, apart from the first image line (6-3), the second significant information is not overlapped with the first image line (6-3). The first image line (7-3) having an image line width of 0.08 mm was continuously arranged in the S1 direction at a pitch of 0.4 mm at a position not overlapping the first image line (6-3). . Hereinafter, the first image line (6-3) having a line width of 0.2 mm is set as the background image line (6-3), and another image line width of 0.08 mm forming the second significant information is set. One image line (7-3) will be described as an information image line (7-3). The information image line (7-3) is arranged at a position not overlapping the background image line (6-3) in the first image (4-3), so that the first image (4-3) is arranged. ) To create a shade based on the difference in area ratio and visualize the second significant information. This first image was printed on the substrate (2-3) by a wet offset printing method using black ink containing carbon black, which is an infrared absorbing material.

  FIG. 23 shows a second image (5-3) and an enlarged view of a part thereof. The second image (5-3) is composed of three second lines (8A-3, 8B-3, 8C-3). Each of the second image lines is formed by continuously arranging image lines having a line width of 0.2 mm at a pitch of 0.4 mm in the S1 direction, and each image line is 0. 0 in the S1 direction. The phase is shifted by 1 mm. The set of one second drawing line (8A-3) represents the background of the alphabet “NIPPON” as the first significant information, and the set of one second drawing line (8B-3) It represents the letter “NIPPON” of the alphabet that is one significant information, and the set of one second drawing line (8C-3) represents the outline of the alphabet “NIPPON” that is the first significant information. Become.

  Advantages of the second image (5-3) having three types of image lines having different phases in the S1 direction as shown in FIG. 23 are as follows. The first significant information is visualized by the interference between the first drawing line and the second drawing line. Taking the embodiment (FIG. 5) as an example, when the first image line (6) and the two second image lines (8A, 8B) overlap, the image overlapped depending on the phase shift in the S1 direction. A combination of lines (first image line (6) and second image line (8A), first image line (6) and second image line (8B)) has the same density. There is. Specifically, the center of the first image line (6) and the center of the second image line (8A) are shifted by a quarter (0.1 mm) of the pitch in the S1 direction. When the image line center of the image line (6) and the image line center of the second image line (8B) are similarly shifted by a quarter (0.1 mm) of the pitch in the S1 direction, The first image line (6) and the second image line (8A), and the first image line (6) and the second image line (8B)) all have a density of about 50%.

  If all the combinations of overlapping image lines have the same density, the character “NIPPON” in the print image (3) and the background in the vicinity have the same density, One significant information cannot be visually recognized, and as a result, the second significant information is visually recognized even under visible light. The configuration of the second image (5-3) shown in the third embodiment is a configuration that avoids such a problem, and the first significant information is not composed of two types of image lines. By configuring with different types of lines, it is possible to prevent all the lines from having the same density and to avoid the situation where the first significant information cannot be visually recognized.

  Even if two second lines (8A-3, 8B-3) out of the second lines have the same density due to the positional relationship of overlapping with the background line (6-3), The second second line (8C-3) has a completely different density, and the outline of the first significant information is visualized. As described above, the first significant information is composed of three types of lines, so that the three second lines (8A-3, 8B-3, 8C-3) and the background line (6-3) ) No matter how the positional relationship of the overlaps changes, at least one of the background, contour, and information itself of the first significant information must be visualized in contrast with the other two The effect of doing can be secured.

  The second image (5-3) having the above-described configuration is obtained by using the slightly offset black ink mainly containing chromo fine black, which does not include an infrared absorbing material, and the first by wet offset printing. The image was printed on the image (4-3).

  FIG. 24 shows the positional relationship of the overlap between the first image (4-3) and the second image (5-3). In the third embodiment, the center of the image line of the background image line (6-3) of the first image (4-3) and the second image line (8A-3) of the second image (5-3). ) Are superimposed in a positional relationship where the image line centers match.

  With the above configuration, the latent image printed material (1-3) of Example 3 was formed. The effect of the latent image printed matter of Example 3 will be described with reference to FIG. FIG. 25A shows an image that can be visually recognized in the printed image (3-3) when the latent image printed matter (1-3) of the third embodiment is observed under visible light. In the observation under visible light shown in FIG. 25 (a), the letter “NIPPON”, which is the first significant information, is black positive (11A-3) in the printed image (3-3). Appeared in. If the phase of printing is shifted by 0.2 mm in the S1 direction from the positional relationship shown in FIG. 24, the letter “NIPPON” as the first significant information is negative (11B-3). ).

  On the other hand, when an infrared viewer (12-3) is used as an authentication device and observed with infrared rays, as shown in FIG. 25 (b), only the first image (4-3) formed with the first ink is present. That is, the letters “NPB” of the alphabet, which is the second significant information, were visible.

  As described above, in the observation with visible light, the first significant information can be visually recognized, and in the observation with one infrared ray, the second significant information can be visually recognized. It was possible to confirm the effect of changing the image in the printed image (3-3).

1, 1-1, 1-2, 1-3 Latent image printed matter 2, 2-1, 2-2, 2-3 base material 3, 3-1, 3-2, 3-3 printed image 4, 4- 1, 4-2, 4-3 1st image 5, 5-1, 5-2, 5-3 2nd image 6, 6-1, 6-2, 6-3 1st image line (background Streak)
7, 7-1, 7-2, 7-3 First drawing line (information drawing line)
8A, 8B, 8A-1, 8B-1, 8-2, 8A-3, 8B-3, 8C-3 Second image line 9, 9-1, 9-2, 9-3 Light source 10, 10- 1, 10-2, 10-3 Observer's viewpoint 11A, 11B, 11A-1, 11B-1, 11A-2, 11B-2, 11A-3, 11B-3 Images observable under visible light 12, 12 -1, 12-2, 12-3 Authentication device

Claims (4)

At least a part of the substrate has a printed image having a color different from that of the substrate,
The printed image is formed by superimposing a first image and a second image,
The first image has a plurality of first image lines that are sequentially arranged at a specific pitch in a specific direction with a first ink,
The second image has a plurality of second image lines that are continuously arranged at the same pitch as the specific pitch in the same direction as the specific direction with the second ink,
i) The first image has first significant information formed by shifting a part of the first image line in a phase in the specific direction, or
ii) the second image has first significant information formed by shifting a part of the second image line in a phase in the specific direction;
The first drawing line is configured so that the background drawing line and the information drawing line do not overlap,
The first image has second significant information formed by the information image line constituting the first image line,
The hues of the first ink and the second ink are close, and the color density of the first image line under visible light is lighter than the color density of the second image line under visible light,
The first image line has a higher color density than the second image line under light of a specific wavelength band,
When observed under visible light, the first significant information is visible in the printed image. When observed under light of the specific wavelength band, the second significant information is displayed in the printed image. A latent image printed matter characterized in that significant information can be visually recognized. The difference between the pitch of the first image line and the pitch of the second image line is in the range of 90% to 110% on the basis of the case where the first image line and the second image line are completely matched. The latent image printed matter according to claim 1, wherein the difference between the line angles of the two lines is within 3 degrees. The difference in the line area ratio between the background image line and the information line is 5% or more and 40% or less, and the line area ratio between the background image line and the second image line is 20% to 80%. The latent image printed matter according to claim 1 or 2, wherein A total image of the plurality of background lines constituting the first image, the plurality of information lines constituting the first image, and the plurality of second lines constituting the second image. The latent image printed matter according to claim 1, wherein the line area ratio is 100% or more and 180% or less.

Images