JP5315580B2 - Latent image printed matter - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a latent image printed matter of which the image changes into different images having no correlation at all under a case being observed under reflective light, and under a case being observed under transmitted light in the field of precious printed matters such as bank notes, passports, securities, identification cards, and traffic tickets which are security printed matters requiring forgery preventing effects. <P>SOLUTION: The latent image printed matter has a printed image at least on part of a base material. The printed image is constituted of a background element group and an information element group. In addition, the background element group is divided into a first printing element group and a second printing element group. The first printing element group is printed with a first ink, and the second printing element group and the information element group are printed with a second ink. A correlative property is imparted in spectral reflectances of the information element, the first printing element, the second printing element and the base material, and a correlative property is imparted in the spectral reflectances of the information element group, the first printing element, the second printing element and the base material. Thus, the latent image printed matter which is superior in the truth/false discrimination and forgery preventing effects, which is constituted by forming a reflective image and a transmitted image, is provided by imparting the correlative property in the spectral reflectances of the information element group, the first printing element, the second printing element and the base material. <P>COPYRIGHT: (C)2011,JPO&amp;INPIT

Description

  In the field of valuable printed matter such as banknotes, passports, securities, identification cards, cards, and passports, which are security printed matters that require anti-counterfeiting effects, the present invention and transmitted light This relates to a latent image print that changes to a different image with no correlation when observed below.

  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. As one of anti-counterfeiting techniques for preventing such duplication and forgery, there is a technique using a metameric pair ink.

  Anti-counterfeiting technology using metameric pair inks utilizes the characteristics that the ink looks the same color or looks different due to the light source and type of illumination and the filter that transmits light of a specific wavelength. is there. In the field of anti-counterfeit printing, a method of utilizing the optical characteristics due to the ink metamerism is conventionally performed.

  For example, it looks the same color under normal light such as sunlight, fluorescent light or incandescent light bulb, but it is viewed under a light source having a predetermined spectral energy distribution, through a predetermined filter, or passed through a predetermined filter. Disclosed is an image forming body characterized in that a pattern is formed on a base material so that a pattern can be contrasted and observed by two kinds of colorants having one of different colors that looks different when viewed under bright light. (For example, refer to Patent Document 1).

  In addition, the present applicant uses a special halftone dot composition by combining a metameric pair ink and a plurality of fine halftone dots and a pixel structure, when observed at the first wavelength in the visible light region, and In the past, there have been applications for authenticity distinguishable printed matter characterized in that different images that are completely uncorrelated are observed when observed at the second wavelength in the visible light range (for example, Patent Document 2 and (See Patent Document 3).

  On the other hand, as one of the representative techniques for preventing counterfeiting, there is a so-called watermark in which a pattern is formed by the density or thinness of a sheet so that the pattern can be visually recognized under transmitted light. However, since this technology needs to be formed at the paper manufacturing stage, it cannot be manufactured unless it is a paper manufacturer. In addition, even if manufactured by a paper manufacturer, there is a problem that the manufacturing cost increases. As a method for reproducing the image, there is a forgery prevention technique for forming a transmission image corresponding to the watermark using a special ink (for example, see Patent Document 4) in a printing process (for example, see Patent Document 5). ). This technology also has a feature that copying is impossible even if a digital device is used.

Japanese Patent Publication No. 60-58711 Japanese Patent No. 4273507 JP 2008-49570 A JP 2000-290571 A JP-A-6-228900

  However, with respect to the techniques described in Patent Document 1, Patent Document 2 and Patent Document 3, in order to determine the authenticity of the anti-counterfeit printed matter formed with the metameric pair ink, a light source having a predetermined spectral energy distribution is used. They had to look down, look through a predetermined filter, or look under the light that passed through the predetermined filter, and had to provide a dedicated light source or filter. This is a problem that everyone who has a printed material like a watermark cannot easily determine authenticity, and the number of persons who can determine is limited.

  In addition, regarding anti-counterfeiting technology using watermark printing that authenticates a transmitted image such as a watermark under transmitted light using a specific ink, penetrating ink itself is commercially available from many manufacturers. However, there is a problem that it is easy to obtain and is easy for a counterfeiter to manufacture. In addition, even if it is formed with semi-transparent or transparent ink, the area where the ink penetrates is observed as a dark color such as oil stain, so compared with the watermark that forms the pattern due to the density or thinness of the paper There is a problem that the transmitted image is easily visually recognized even under reflected light. When the amount of ink is suppressed to such a level that it is difficult to visually recognize as a reflected image, the transmitted image becomes unclear, and when the amount of ink is increased to such an extent that the transmitted image is easily visible, it tends to appear strongly as a reflected image.

  The present invention is intended to solve the above-mentioned problems, and is observed in the same color under reflected light when printed on a base material, but is used as a pair ink by combining two inks having different transmittances. In addition, it is a printed matter that forms an image with a special and complicated halftone dot configuration, and does not require a special light source or filter like a forgery prevention printed matter formed with a metameric pair ink, and is commercially available like watermark printing. It cannot be formed simply by obtaining ink, and the image that can be observed under reflected light and the image that can be observed under transmitted light are different images that have no correlation at all. Involved in excellent latent image prints.

  The latent image printed material of the present invention is a latent image printed material having a printed image of a color different from that of the substrate on at least a part of the substrate, and the printed image is formed with a certain area ratio formed by arranging a plurality of elements. A background element group and an information element group in which a plurality of elements are arranged so as not to overlap with the elements forming the background element group. The background element group is formed by a difference in ink. The printing element group is divided into the second printing element group, the first printing element group and the information element group are formed with the first ink, and the second printing element group is formed with the second ink. The spectral reflectance of the first printing element group has a spectral reflectance equal to the spectral reflectance of the second printing element group, and the spectral reflectance of the first printing element group, The spectral reflectance of the printing element group and the spectral reflectance of the information element group are based on the spectral reflectance of the substrate. The spectral transmittance of the first print element group has a higher spectral transmittance than the spectral transmittance of the second print element group and the spectral transmittance of the information element group; and The spectral transmittance of the second printing element group and the spectral transmittance of the information element group have a spectral transmittance equal to the spectral transmittance of the substrate, and when observed under transmitted light, the second printing element group The printed image is visually recognized when visually recognized and observed under reflected light.

  The latent image printed matter of the present invention is characterized in that the elements forming the background element group are pixels and / or image lines.

  The latent image printed matter of the present invention is characterized in that the elements forming the information element group are pixels and / or image lines.

  In the latent image printed matter of the present invention, in the wavelength region from 400 nm to 700 nm, the integral value of the transmission spectrum in the first printing element group is 120% or more of the integral value of the transmission spectrum in the second printing element group and the information element group. Have

  The latent image printed matter of the present invention is characterized in that the first ink and / or the second ink are mixed with a functional material.

  In the latent image printed matter of the present invention, authenticity can be determined by confirming that different images are observed when the printed matter is observed under reflected light and when observed under transmitted light, There is no need for special light sources or filters, and no need for special tools.

  The latent image printed matter of the present invention cannot be formed by simply printing a commercially available penetrating ink, and in forming this, when printed on a base material, it is the same color under penetrating ink and reflected light. Therefore, it is necessary to produce another ink having optical characteristics with different transmittances. For this purpose, it is impossible to easily counterfeit because it requires skills and equipment for ink production. .

  In the latent image printed matter of the present invention, by using a special halftone dot configuration, an image observed under reflected light and an image observed under transmitted light can be made to have no correlation at all. There is a high degree of freedom in design.

  The latent image printed material of the present invention is characterized in that the transmitted image is visualized as a reflected image in the first place, and it is necessary to limit the amount of penetrating ink transferred to paper as in the conventional watermark printing technique. Therefore, a very clear transmission image can be formed.

  The latent image printed matter formed by the above method can be manufactured by offset printing, which is a highly productive printing method, so it has excellent cost performance, and transmission images cannot be reproduced even with the latest digital equipment. Therefore, the anti-counterfeiting effect is excellent.

(A) shows a latent image printed material according to the present invention, (b) shows a background element group, and (c) shows an information element group. (A) shows the 1st printing element group in this invention, (b) shows the 2nd printing element group in this invention. (A) shows the 2nd printing element group and information element group which are formed with 2nd ink in this invention, (b) shows the 1st printing element group which is formed with 1st ink in this invention. Show. The spectral reflectance of a 1st ink, a 2nd ink, and a base material is shown. The spectral transmittance of a 1st ink, a 2nd ink, and a base material is shown. (A) shows the image in which the latent image printed material in the present invention is visually recognized under reflected light, and (b) shows the image in which the latent image printed material in the present invention is visually recognized under transmitted light. The integrated value of the transmission spectrum is shown. (A) shows a latent image printed material according to an embodiment of the present invention, (b) shows a background element group, and (c) shows an information element group. (A) shows the 1st printing element group in one Example of this invention, (b) shows the 2nd printing element group in one Example of this invention. (A) shows the 2nd printing element group and information element group which are formed with the second ink in one embodiment of the present invention, and (b) is formed with the first ink in one embodiment of the present invention. 1 shows a first printing element group. (A) shows an image in which the latent image printed matter in one embodiment of the present invention is visually recognized under reflected light, and (b) shows an image in which the latent image printed matter in one embodiment of the present invention is visually recognized under transmitted light. Show. (A) shows a latent image printed material according to an embodiment of the present invention, (b) shows a background element group, and (c) shows an information element group. (A) shows the 1st printing element group in one Example of this invention, (b) shows the 2nd printing element group in one Example of this invention. (A) shows the 2nd printing element group and information element group which are formed with the second ink in one embodiment of the present invention, and (b) is formed with the first ink in one embodiment of the present invention. 1 shows a first printing element group. (A) shows an image in which the latent image printed matter in one embodiment of the present invention is visually recognized under reflected light, and (b) shows an image in which the latent image printed matter in one embodiment of the present invention is visually recognized under transmitted light. Show. (A) shows a latent image printed material according to an embodiment of the present invention, (b) shows a background element group, and (c) shows an information element group. (A) shows the 1st printing element group in one Example of this invention, (b) shows the 2nd printing element group in one Example of this invention. (A) shows the 2nd printing element group and information element group which are formed with the second ink in one embodiment of the present invention, and (b) is formed with the first ink in one embodiment of the present invention. 1 shows a first printing element group. (A) shows an image in which the latent image printed matter in one embodiment of the present invention is visually recognized under reflected light, and (b) shows an image in which the latent image printed matter in one embodiment of the present invention is visually recognized under transmitted light. Show. (A) shows a latent image printed material according to an embodiment of the present invention, (b) shows a background element group, and (c) shows an information element group. (A) shows the 1st printing element group in one Example of this invention, (b) shows the 2nd printing element group in one Example of this invention. (A) shows the 2nd printing element group and information element group which are formed with the second ink in one embodiment of the present invention, and (b) is formed with the first ink in one embodiment of the present invention. 1 shows a first printing element group. (A) shows an image in which the latent image printed matter in one embodiment of the present invention is visually recognized under reflected light, and (b) shows an image in which the latent image printed matter in one embodiment of the present invention is visually recognized under transmitted light. Show. (A) shows a latent image printed material according to an embodiment of the present invention, (b) shows a background element group, and (c) shows an information element group. (A) shows the 1st printing element group in one Example of this invention, (b) shows the 2nd printing element group in one Example of this invention. (A) shows the 2nd printing element group and information element group which are formed with the second ink in one embodiment of the present invention, and (b) is formed with the first ink in one embodiment of the present invention. 1 shows a first printing element group. (A) shows an image in which the latent image printed matter in one embodiment of the present invention is visually recognized under reflected light, and (b) shows an image in which the latent image printed matter in one embodiment of the present invention is visually recognized under transmitted light. Show.

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

  Next, the present invention will be described with reference to the drawings. FIG. 1A shows a latent image printed material according to the present invention, FIG. 1B shows a background element group, and FIG. 1C shows an information element group. FIG. 2A shows a first printing element group in the present invention, and FIG. 2B shows a second printing element group in the present invention. FIG. 3A shows a second printing element group and an information element group formed with the second ink in the present invention, and FIG. 3B shows a first printing element group formed with the first ink in the present invention. A print element group is shown. FIG. 4 shows the spectral reflectance of the first ink, the second ink and the substrate. FIG. 5 shows the spectral transmittance of the first ink, the second ink and the substrate. 6A shows an image in which the latent image printed material in the present invention is visually recognized under reflected light, and FIG. 6B shows an image in which the latent image printed material in the present invention is visually recognized under transmitted light. FIG. 7 shows the integral value of the transmission spectrum. FIG. 8A shows a latent image printed material according to an embodiment of the present invention, FIG. 8B shows a background element group, and FIG. 8C shows an information element group. FIG. 9A shows a first printing element group in one embodiment of the present invention, and FIG. 9B shows a second printing element group in one embodiment of the present invention. FIG. 10A shows a second printing element group and an information element group formed with the second ink in one embodiment of the present invention, and FIG. 10B shows the first printing element group and the information element group formed in the second embodiment. 1 shows a first group of printing elements formed with ink. FIG. 11A shows an image in which the latent image printed material in one embodiment of the present invention is visually recognized under reflected light, and FIG. 11B shows the latent image printed material in an embodiment of the present invention visually recognized in transmitted light. The image to be displayed is shown. FIG. 12A shows a latent image printed material according to an embodiment of the present invention, FIG. 12B shows a background element group, and FIG. 12C shows an information element group. FIG. 13A shows a first printing element group in one embodiment of the present invention, and FIG. 13B shows a second printing element group in one embodiment of the present invention. FIG. 14A shows a second printing element group and an information element group formed with the second ink in one embodiment of the present invention, and FIG. 14B shows the first printing element group and the information element group formed in the second embodiment. 1 shows a first group of printing elements formed with ink. FIG. 15A shows an image in which the latent image printed matter in one embodiment of the present invention is visually recognized under reflected light, and FIG. 15B shows the latent image printed matter in one embodiment of the present invention visually recognized under transmitted light. The image to be displayed is shown. FIG. 16A shows a latent image printed material according to an embodiment of the present invention, FIG. 16B shows a background element group, and FIG. 16C shows an information element group. FIG. 17A shows a first printing element group in one embodiment of the present invention, and FIG. 17B shows a second printing element group in one embodiment of the present invention. FIG. 18A shows a second printing element group and an information element group formed with the second ink in one embodiment of the present invention, and FIG. 18B shows the first printing element group and the information element group formed in the second embodiment. 1 shows a first group of printing elements formed with ink. FIG. 19A shows an image in which the latent image printed matter in one embodiment of the present invention is visually recognized under reflected light, and FIG. 19B shows the latent image printed matter in one embodiment of the present invention visually recognized under transmitted light. The image to be displayed is shown. FIG. 20A shows a latent image printed material according to an embodiment of the present invention, FIG. 20B shows a background element group, and FIG. 20C shows an information element group. FIG. 21A shows a first printing element group in one embodiment of the present invention, and FIG. 21B shows a second printing element group in one embodiment of the present invention. FIG. 22A shows a second printing element group and an information element group formed with the second ink in one embodiment of the present invention, and FIG. 22B shows the first printing element group and the information element group formed in the second embodiment. 1 shows a first group of printing elements formed with ink. FIG. 23A shows an image in which the latent image printed matter in one embodiment of the present invention is visually recognized under reflected light, and FIG. 23B shows the latent image printed matter in one embodiment of the present invention visually recognized under transmitted light. The image to be displayed is shown. FIG. 24A shows a latent image printed material according to an embodiment of the present invention, FIG. 24B shows a background element group, and FIG. 24C shows an information element group. FIG. 25A shows a first printing element group in one embodiment of the present invention, and FIG. 25B shows a second printing element group in one embodiment of the present invention. FIG. 26A shows a second printing element group and an information element group formed with the second ink in one embodiment of the present invention, and FIG. 1 shows a first group of printing elements formed with ink. FIG. 27A shows an image in which the latent image printed matter in one embodiment of the present invention is visually recognized under reflected light, and FIG. 27B shows the latent image printed matter in one embodiment of the present invention visually recognized under transmitted light. The image to be displayed is shown.

  FIG. 1A shows a latent image print (1) according to the present invention. In the latent image printed matter (1), a printed image (3) having a color different from that of the base material is formed on the base material (2), and the printed image (3) has a background shown in FIG. It consists of an element group (4) and an information element group (5) shown in FIG. The background element group (4) shown in FIG. 1B is visually recognized with a certain gradation (density) by regularly arranging elements (6) having a certain form. In the information element group (5) shown in FIG. 1C, the element (7) having a different form from the element (6) forming the background element group (4) forms the background element group (4). The information element group (5) causes a gradation difference (density difference) in the background element group (4) and is visually recognized as the letter “A” in the alphabet. The In other words, the printed image (3) is an element forming the information element group (5) in a flat gradation generated by the plurality of elements (6) forming the background element group (4). By arranging (7), a portion with an area ratio higher than that of the background element group (4) is generated in the arranged portion, and the letter “A” is formed by the portion where the difference in area ratio occurs. The Rukoto.

  The “element (6) forming the background element (4)” in the present invention refers to a pixel or an image line, and the “element (7) forming the information element (5)” in the present invention. The term “pixel” refers to a pixel or an image line. The “pixel” here is a halftone dot shape that is used as one element for forming the print image (3) and expresses a change in shading with an area ratio (the size of a point). The “image line” means a broken line, a broken line, a straight line, a curve, or a wavy line, and any image line shape is included in the technical idea of the present invention.

  The “information element group (5) is different from the element (6) that forms the background element group (4) in the element (7) that forms the background element group (4) ( “Different forms” in “arranged so as not to overlap with 6) only have to be different in size, shape, or phase.

  In the present invention, the element (6) forming the background element group (4) is composed of pixels and / or lines, and the element (7) forming the information element group (5) is composed of pixels and / or lines. Become. However, in the case of the information element group (5), a rectangular image which is one of the elements (7) may be arranged adjacent to each other without any gap, and a solid image may be formed. Thus, a gradation image may be used. Thus, in the element (7) of the information element group (5), part of the area ratio in the print image (3) is made different so as not to overlap with the element (6) of the background element group (4). Any form may be used as long as it is a form. In addition, with regard to the combination of the element (6) forming the background element group (4) and the element (7) forming the information element group (5), the latent image printed material of the present invention can be produced in all combinations. . In the embodiment for carrying out the present invention, the element (6) forming the background element group (4) and the element (7) forming the information element group (5) are halftone dots. explain.

  In the case of the latent image printed material (1) shown in FIG. 1, in the background element group (4) shown in FIG. 1 (b), a plurality of elements (6) forming halftone dots of a certain size are regularly arranged. The information element group (5) shown in FIG. 1 (c) has a larger diameter than the element (6) forming the background element group (4). A plurality of elements (7) composed of halftone dots are regularly arranged so as not to overlap with the elements (6) forming the background element group (4).

  Thus, the printed image (3) forms the information element group (5) in the flat gradation created by the plurality of elements (6) forming the background element group (4). Element (7) is arranged, a portion having a higher gradation than the background element group (4) is generated in the arranged portion, and the letter “A” is formed by the portion where the gradation difference occurs. Is done.

  In the present embodiment, the background element group (4) is formed from a plurality of elements (6) that form halftone dots of a certain size, and the information element group (5) forms the background element group (4). However, the present invention is not limited to this form, and the present invention is not limited to the flat shape. The area ratio may be different depending on the plurality of elements (7) forming the information element group (5) so as to produce a gradation difference with respect to the background element group (4) having a different gradation. .

  For example, a mode in which the halftone dots forming the information element group (5) are shifted in phase between the halftone dots forming the background element group (4), and the halftone dots forming the background element group (4) A form in which a solid image forming the information element group (5) is arranged in a part of the area other than the point, and the information element group (5) is formed between the lines forming the background element group (4). A form in which the image lines to be arranged are arranged adjacent to each other, and a form in which the gradation image forming the information element group (5) is arranged in a part of the region other than the halftone dots forming the background element group (4) It is done. These forms will be specifically described in Examples 1 to 5 described later.

  The element (6) forming the background element group (4) and the element (7) forming the information element group (5) need to be formed so as not to overlap. This is because when the element (6) forming the background element group (4) and the element (7) forming the information element group (5) are formed overlappingly, the gradation is increased only by the overlapping part. Therefore, when the latent image printed material (1) of the present invention is observed under reflected light, the problem that the characters “OK” that the first printing element group (8) that should not be visually recognized can be visually recognized is visually recognized. This is because.

  FIG. 2 shows two element groups constituting the background element group (4). FIG. 2A shows the first printing element group (8), and FIG. 2B shows the second printing element group (9). The first printing element group (8) shown in FIG. 2 (a) is configured to form the letters “OK” of the alphabet, and the second printing element group (9) shown in FIG. In this configuration, the characters “OK” in the first print element group (8) are removed from the element group (4). As described above, the first print element group (8) and the second print element group (9) form a pair image, and characters, symbols, and the like included in the first print element group (8). The meaningful image is camouflaged by the second print element group (9) and is hidden in the background element group (4) having a certain gradation.

  Since the first printing element group (8) is camouflaged by the second printing element group (9) and hidden in the background element group (4) having a certain gradation, the first printing element group (8) The area ratio of the element group (8) and the area ratio of the second printing element group (9) are the same.

  FIG. 3 shows respective images formed by the first ink and the second ink in the present invention. FIG. 3A shows an image formed with the second ink, which is configured by combining the information element group (5) and the second printing element group (9). FIG. 3B is an image formed with the first ink, and is composed of only the first printing element group (8).

  As described above, the first printing element group (8) formed with the first ink and the second printing element group (9) formed with the second ink are combined to form the background element group (4). And the information element group (5) formed of the second ink is added to the background element group (4), thereby forming the printed image (3) formed on the latent image print in the present invention. Yes.

  Next, the first ink and the second ink used in the present invention will be described. When the first ink is printed on the substrate (2) and when the second ink is printed on the substrate (2) and each printed matter is configured with the same area ratio, when observed under reflected light It has characteristics that are observed in the same color and has different light transmittance.

  Next, the spectral reflectance and spectral transmittance of the print sample formed with the first ink on the substrate (2) and the print sample formed with the second ink will be described. The sample for measuring the spectral reflectance and the spectral transmittance is obtained by using high-quality skin-colored paper as the base material (2) and performing 100% solid printing of the first ink and the second ink. . Further, a VSC5000 manufactured by foster + freeman is used for the measurement of the spectral reflectance and the spectral transmittance.

  Hereinafter, for the sake of clarity, the “printed sample formed with the first ink on the substrate (2)” will be referred to as the “first sample” and the “printed sample on the substrate (2)”. The “printed sample formed with the second ink” is referred to as “second sample”.

  FIG. 4 shows the spectral reflectance (10R) of the first sample, the spectral reflectance (11R) of the second sample, and the spectral reflectance (12R) of the substrate (2). From the graph of FIG. 4, since the spectral reflectance (10R, 11R) of the first sample and the second sample is almost the same, the first sample and the second sample are visually the same color. It can be seen that it is observed. Moreover, although it is similar to the spectral reflectance (10R, 11R) of the first sample and the second sample and the spectral reflectance (12R) of the base material (2), the spectral reflectance of the base material (2) ( Since it is lower than 12R), it can be seen that the first sample and the second sample have characteristics that are recognized by the observer as colors in which the color of the substrate (2) is slightly darkened.

  FIG. 5 shows the spectral transmittance (10T) of the first sample, the spectral transmittance (11T) of the second sample, and the spectral transmittance (12T) of the substrate (2). From the graph of FIG. 5, the spectral transmittance (10T) of the first sample is about 10% higher than the spectral transmittance (11T, 12T) of the second sample and the substrate, and further, The spectral transmittance (11T) is substantially the same as the spectral transmittance (12R) of the substrate (2). A high spectral transmittance means that the image is viewed brightly when observed under transmitted light. Therefore, when observed under transmitted light, the first sample is viewed brighter than the second sample and the base material, and the second sample has the same spectral transmittance (12T) as the base material (2). As a result, it becomes indistinguishable from the base material, and it can be seen that it has a feature that is visually invisible.

  From the above results, the image formed on the substrate (2) with the first ink and the image formed on the substrate (2) with the second ink are under reflected light if the area ratio is equal. When observed with transmitted light, the image formed with the first ink is viewed brightly, and the image formed with the second ink is the same color as the substrate. It turns out that it becomes difficult to see.

  Based on the above results, the effect of the latent image printed material (1) of the present invention will be described. When the latent image printed matter (1) of the present invention is observed under reflected light, the first printing element group (8) formed with the first ink and the second printing element formed with the second ink. Since the printing element group (9) has the same area ratio, the printing element group (9) is visually recognized as the same color, and the character “OK” indicated by the first printing element group (8) is completely camouflaged by the second printing element group. Is done. The observer has the area ratio of the background element group (4) having a flat gradation formed by combining the first printing element group (8) and the second printing element group (9). The information element group (5) composed of the letter “A” formed by the difference is observed with a darker color than the background element group (4). That is, the printed image (3) shown in FIG. 6A is visually recognized in a slightly darker color than the base material (2).

  In addition, when the latent image printed matter (1) of the present invention is observed under transmitted light, the first printing element group (8) formed with the first ink is the first printing element group (8) formed with the second ink. The second printing element group (9) and the information element group (5), and the second printing element group (9) and the second printing element group (9) which are viewed brighter than the base material (2) which is paper and are formed of the second ink. Since the information element group (5) has the same color as the base material (2) and is difficult to visually recognize, the viewer is given a first “OK” character as shown in FIG. Only the printing element group (8) is visible brighter than the substrate (2).

  As described above, when the latent image printed material (1) of the present invention is observed under reflected light, a printed image composed of characters “A” formed at different area ratios in the background element group (4). A first printing element comprising the letters “OK” formed by the first ink when (3) is viewed in a slightly darker color than the substrate (2) and observed under transmitted light Group (7) is visible brighter than substrate (2). As described above, since different images having no correlation are visually recognized in the observation under the reflected light and the transmitted light, the authenticity discrimination is excellent.

  In the embodiment for carrying out the present invention, skin-quality fine paper was used as the base material (2), but the color of the base material is not limited to the skin color. A colored substrate may be used, and the latent image printed material of the present invention can be formed as long as the substrate has a transmittance of 100% and is not transparent. However, the second ink is a color that is observed under reflected light when the first ink penetrates into the substrate, and a color that is observed under reflected light when the second ink penetrates into the substrate. Therefore, if the base material changes, the second ink needs to be toned accordingly.

  First, two pair inks of the first ink and the second ink will be described. When the pair ink is printed on the substrate with the same area ratio, the spectral reflectance of the first ink and the spectral reflectance of the second ink are substantially the same, and the spectral reflectance of the first ink The spectral reflectance of the second ink is lower than the spectral reflectance of the substrate, and further, the spectral transmittance of the first ink needs to be larger than that of the second ink. In addition, as described above, when observed under transmitted light, the observer feels the impression that the second printing element group (9) and the information element group (5) are assimilated with the base material (2) and disappeared. Giving gives a role to further enhance the effect of authenticity determination of the latent image printed matter (1) in the present invention, and therefore the spectrum when the second ink is printed on the substrate (2) at a constant area ratio. The transmittance and the spectral transmittance of the substrate (2) are formed to be the same.

  Spectral reflectance when the first ink is printed on the base material (2) with a constant area ratio, and spectral spectrum when the second ink is printed on the base material (2) with the same area ratio as the first ink The reason why the reflectance is the same and lower than the spectral reflectance of the substrate is that when the latent image printed matter (1) of the present invention is observed under reflected light, the first printing element group (8) and the first printing element group (8) This is because the second printing element group (9) is made the same color and the first printing element group (8) is concealed. If the spectral reflectances are different, when the latent image print (1) of the present invention is observed under reflected light, the first printing element group (8) and the second printing element group (9) Since they are recognized in different colors, there arises a problem that the characters “OK”, which is the meaningful information formed by the first print element group (8), are visually recognized.

  In addition, when the first ink is printed on the substrate (2) with a constant area ratio, the second ink is printed on the substrate (2) with the same area ratio as the first ink. The spectral transmittance when the second ink is printed on the base material (2) with a constant area ratio is made substantially the same as the spectral transmittance of the base material (2). When the latent image printed matter (1) of the present invention is observed under transmitted light, the second printing element group (9) and the information element group (5) are the same color as the base material (2), This is because the printing element group (8) is observed brighter than the substrate (2) and the second printing element group (9) formed with the first ink and the information element group (5). If the spectral transmittance of the first printing element group (8) and the second printing element group (9) is the same as that of the information element group (5), the latent image printed matter (1) of the present invention is transmitted. When observed under light, the first printing element group (8), the second printing element group (9), and the information element group (5) are all observed, resulting in a change from the image that can be observed under reflected light. It will disappear. Further, even when the second printing element group (9) and the information element group (5) and the base material (2) are not the same color under transmitted light, the latent image printed material (1) of the present invention is observed under transmitted light. In this case, since the second print element group (9) and the information element group (5) are also visually recognized, the characters “OK” and the information element group (the first print element group (8)) ( The character “A”, which is an image formed by 5), is mixed, resulting in an unclear image.

Regarding the difference in spectral transmittance between when the first ink is printed on the base material (2) and when the second ink is printed on the base material (2), it is easy to visually check the authenticity. For the purpose, the integral value of the transmission spectrum of the first ink in the wavelength range of 400 nm to 700 nm, which is visible light, needs to reach 120% or more of the integral value of the transmission spectrum of the second ink.
The integral value of the transmission spectrum is the first print sample indicated by the hatched portion in FIG. 7B with respect to the area ratio of the spectral transmittance (11T) of the second print sample indicated by the hatched portion in FIG. It is represented by the ratio of the area ratio of the spectral transmittance (10T).

  This is because when the integral value of the transmission spectrum of the second print sample is smaller than 120% of the integral value of the transmission spectrum of the first print sample, the latent image print (1) of the present invention was observed under transmitted light. The visibility of the first printing element group (8) at the time is reduced. Further, the upper limit of the integral value of the transmission spectrum of the first ink is preferably as large as possible since the visibility when the latent image print (1) of the present invention is observed under transmitted light is improved.

  For the first ink, a penetrating ink may be used. Even if the ink is marketed as transparent or translucent, when it is formed on the substrate with an appropriate printed film thickness, the printed part looks like an oil stain and is visualized in a darker color than the substrate Therefore, it has the characteristic of forming a visible image under the reflected light necessary for the present invention. The desired properties of the first ink are that it penetrates the substrate sufficiently during printing and the spectral transmittance of the printing area increases, the ink itself is nearly transparent or translucent, and the color changes over time. Is small and there is little bleeding. If these characteristics are satisfied, there is no problem even if an ink other than those sold as penetrating ink is used.

  The first ink may be colored and translucent by adding a small amount of a coloring pigment. In this case, the degree of freedom in design is improved. However, if the ink is excessively colored, care must be taken because the spectral transmittance is lowered even if the ink has excellent permeability. It is necessary to determine an appropriate blending ratio of the pigment. In this case, the second ink needs to be colored in the same way to finish the same color as the first ink.

  Moreover, a functional material may be mixed with the first ink and the second ink to give a special authentication function. For example, a luminescent pigment may be mixed with any ink to impart the characteristic that any printing element emits light when irradiated with black light, or an infrared absorbing material may be mixed to provide an infrared authentication function. Is possible. In addition, phosphorescent pigments, phosphorescent pigments, photochromic pigments, temperature indicating materials, thermochromic materials, and the like can be given. As mentioned earlier, the penetrating ink is used for the first ink. However, some penetrating inks exhibit infrared absorption characteristics when printed, and have such characteristics. By using the ink as the first ink, it is possible to visually recognize the first printing element group with a simple discriminating tool such as an infrared viewer.

  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 it is possible to use ink having high penetrability, 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.

  Further, the configuration of elements for forming the latent image printed material (1) of the present invention is not limited to the configuration described in the embodiment. As a configuration of the elements, the first printing element group (8) and the second printing element group (9) are combined to form a fixed background element group (4), and the background element group (4) It is only necessary that the print image is configured by forming the information element group (5) at a different area ratio.

  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. In Example 1, high-quality paper (manufactured by Nippon Paper Industries Co., Ltd.) was used as the base material (2-1).

  FIG. 8A shows a latent image print (1-1) according to the present invention. In the latent image print (1-1), a print image (3-1) having a color different from that of the base material is formed on the base material (2-1), and the print image (3-1) is It consists of a background element group (4-1) shown in FIG. 8 (b) and an information element group (5-1) shown in FIG. 8 (c). The background element group (4-1) shown in FIG. 8 (b) has a certain gradation by arranging the elements (6-1) having a halftone dot with a diameter of 1 mm regularly at a pitch of 2 mm. The information element group (5-1) shown in FIG. 8C has a diameter 2 mm larger than the element (6-1) forming the background element group (4-1) and the line width 0. Element (7-1) consisting of halftone dots with a 25 mm outline is regularly arranged at a pitch of 2 mm so as not to overlap with the background element group (4-1), and the information element group (4-1) Causes a difference in area ratio and is visually recognized as the letter “A” in the alphabet. That is, the print image (3-1) includes an information element group (5-) in a flat gradation created by a plurality of elements (6-1) forming the background element group (4-1). By arranging the element (7-1) forming 1), a portion having a higher area ratio than the background element group (4-1) is generated in the arranged part, and the difference in the area ratio is The letter “A” is formed by the resulting portion.

  FIG. 9 shows two element groups constituting the background element group (4-1). FIG. 9A shows the first printing element group (8-1), and FIG. 9B shows the second printing element group (9-1). The first printing element group (8-1) shown in FIG. 9A is a configuration showing the letters “OK” of the alphabet, and the second printing element group (9-1) shown in FIG. ) Has a configuration in which the characters “OK” of the first print element group (8-1) are removed from the background element group (4-1).

  FIG. 10 shows respective images formed by the first ink and the second ink. FIG. 10A shows an image formed with the second ink, and has a configuration in which the information element group (5-1) and the second printing element group (9-1) are combined. The image shown in FIG. 10A was printed on the substrate (2-1) by offset printing using the second ink produced with the formulation shown in Table 1. FIG. 10B is an image formed with the first ink, and is composed of only the first printing element group (8-1). The image shown in FIG. 10B was printed on the substrate (2-1) by offset printing using the offset ink “Unimark” manufactured by Teikoku Ink & Co., Ltd.

  The first ink and the second ink have substantially the same spectral reflectance when printed on the substrate with the same area ratio, and the first ink has a spectral transmittance higher than that of the second ink. Has great properties. Therefore, when the first ink and the second ink are printed on the base material with the same area ratio, they are observed in the same color in the observation under the reflected light, and the first ink in the observation under the transmitted light. The printed image appears brighter than the image printed with the second ink. In the case of Example 1, the integral value of the transmission spectrum in the first printing element group has 150% of the integral value of the transmission spectrum in the second printing element group and the information element group.

  The effect in Example 1 of this invention is demonstrated using FIG. When the latent image print (1-1) of the present invention is observed under reflected light, it is formed with the first printing element group (8-1) formed with the first ink and the second ink. Since the second print element group (9-1) is visually recognized to be substantially the same color, the observer will receive the printed image (3-1) shown in FIG. It can be visually recognized at a density slightly darker than the paper color of 1).

  When the latent image print (1-1) of the present invention is observed under transmitted light, the second print element group (9-1) and the information element group (5- 1) is the same color as the skin-colored paper which is the base material (2-1), and the first printing element group (8-1) formed with the first ink includes the base material (2-1) and Since it is viewed brighter than the first printing element group (9-1) and the information element group (5-1) formed with the second ink, the observer sees as shown in FIG. The first printing element group (8-1) consisting of the letters “OK” formed by the first ink is visible brighter than the base material (2-1).

  As described above, when observed under reflected light, the difference in area ratio is generated by forming the information element group (5-1) in the background element group (4-1). When the printed image (3-1) composed of characters is viewed darker than the base material (2-1) and is observed under transmitted light, the printed image (3-1) is composed of characters “OK” formed by the first ink. One printing element group (8-1) is visually recognized brighter than the base material (2-1). In this way, different images with no correlation were confirmed in observation under reflected light and transmitted light.

  A second embodiment of the present invention will be described with reference to FIGS. In Example 2, a general white-colored fine paper (manufactured by Nippon Paper Industries Co., Ltd.) was used as the base material (2-2).

  FIG. 12A shows a latent image printed material (1-2) according to the present invention. In the latent image printed matter (1-2), a printed image (3-2) having a color different from that of the substrate is formed on the substrate (2-2), and the printed image (3-2) It consists of a background element group (4-2) shown in FIG. 12 (b) and an information element group (5-2) shown in FIG. 12 (c). In the background element group (4-2) shown in FIG. 12 (b), the elements (6-2) having halftone dots having a diameter of 0.5 mm are regularly arranged at a pitch of 0.8 mm. The information element group (5-2) shown in FIG. 12C, which is visually recognized with gradation, has the same diameter of 0. 0 as the element (6-2) forming the background element group (4-2). Elements (7-2) having a halftone dot of 5 mm are regularly arranged at a pitch of 0.8 mm so as not to overlap with the background element group (4-2), and the information element group (4-2) A difference in area ratio occurs, which is visually recognized as the letter “COPY” in the alphabet. The element (6-2) constituting the background element group (4-2) and the element (7-2) constituting the information element group (5-2) have a phase of 0.4 mm vertically and horizontally. Are different, there is no overlapping part. Therefore, the print image (3-2) includes the information element group (5-2) in the flat gradation created by the plurality of elements (6-2) forming the background element group (4-2). ) Forming the portion (7-2) forming a portion, a portion having a higher area ratio than the background element group (4-2) is generated in the arranged portion, and a difference in the area ratio is generated. The characters “COPY” are formed by the portions.

  FIG. 13 shows two element groups constituting the background element group (4-2). FIG. 13A shows the first printing element group (8-2), and FIG. 13B shows the second printing element group (9-2). The first print element group (8-2) shown in (a) is a configuration showing the letters “OK” of the alphabet, and the second print element group (9-2) shown in (b) is a background. In this configuration, the character “OK” of the first print element group (8-2) is removed from the element group (4-2).

  FIG. 14 shows respective images formed by the first ink and the second ink. (A) is an image formed with the second ink, and has a configuration in which the information element group (5-2) and the second printing element group (9-2) are combined. The image shown in FIG. 14A was printed on the substrate (2-2) by offset printing using the second ink prepared with the formulation shown in Table 2. (B) is an image formed with the first ink, and is composed only of the first printing element group (8-2). The image shown in FIG. 14B was printed on the substrate (2-2) by offset printing using the offset ink “Unimark” manufactured by Teikoku Mfg. Co., Ltd.

  The first ink and the second ink have substantially the same spectral reflectance when printed on the substrate with the same area ratio, and the first ink has a spectral transmittance higher than that of the second ink. Has great properties. Therefore, when the first ink and the second ink are printed on the base material with the same area ratio, they are observed in the same color in the observation under the reflected light, and the first ink in the observation under the transmitted light. The printed image appears brighter than the image printed with the second ink. In the case of Example 2, the integral value of the transmission spectrum in the first printing element group has 140% of the integral value of the transmission spectrum in the second printing element group and the information element group.

  The effect in Example 2 of this invention is demonstrated using FIG. When the latent image printed matter (1-2) of the present invention is observed under reflected light, it is formed with the first printing element group (8-2) formed with the first ink and the second ink. Since the second printing element group (9-2) is visually recognized to be almost the same color, the printed image (3-2) including the characters “COPY” shown in FIG. However, it can be visually recognized at a density slightly darker than the color of the paper as the base material (2-2).

  When the latent image printed material (1-2) of the present invention is observed under transmitted light, the second printing element group (9-2) and the information element group (5- 2) is the same color as the skin-colored paper which is the base material (2-2), and the first printing element group (8-2) formed with the first ink includes the base material (2-2) and Since it is viewed brighter than the first printing element group (9-2) and the information element group (5-2) formed with the second ink, as shown in FIG. The first printing element group (8-2) consisting of the letters “OK” formed by the first ink is brighter than the base material (2-2).

  As described above, when observed under reflected light, the information element group (5-2) is formed in the background element group (4-2), resulting in a difference in area ratio. When the printed image (3-2) composed of characters is viewed darker than the substrate (2-2) and is observed under transmitted light, the printed image (3-2) composed of characters “OK” formed by the first ink is used. One printing element group (8-2) is visually recognized brighter than the base material (2-2). In this way, different images with no correlation were confirmed in observation under reflected light and transmitted light.

  A third embodiment of the present invention will be described with reference to FIGS. In Example 3, a general white-colored high-quality paper (manufactured by Nippon Paper Industries Co., Ltd.) was used as the base material (2-3).

  FIG. 16A shows a latent image print (1-3) in the present invention. In the latent image print (1-3), a print image (3-3) having a color different from that of the base material is formed on the base material (2-3), and the print image (3-3) It is composed of a background element group (4-3) shown in FIG. 16B and an information element group (5-3) shown in FIG. In the background element group (4-3) shown in FIG. 16 (b), the elements (6-3) having a halftone dot having a diameter of 0.3 mm are regularly arranged at a pitch of 0.5 mm. The information element group (5-3) shown in FIG. 16 (c) is solidly touched with the element (6-3) forming the background element group (4-3). The area ratio is different depending on the information element group (4-3) and is visually recognized as the letter “COPY”. As described above, even when a solid element is formed as an element, the element (6-3) that forms the background element group (4-3) and the element (7-) that forms the information element group (5-3) 3) is configured not to overlap. The background print image (3-3) includes an information element group (5-3) in a flat gradation created by a plurality of elements (6-3) forming the background element group (4-3). When the element (7-3) forming the pattern is arranged, a portion having a higher area ratio than the background element group (4-3) is generated in the arranged part, and a difference in the area ratio is generated. The character “COPY” is formed by the portion.

  FIG. 17 shows two element groups constituting the background element group (4-3). FIG. 17A shows the first printing element group (8-3), and FIG. 17B shows the second printing element group (9-3). The first printing element group (8-3) shown in FIG. 17A has a configuration showing the letters “OK” of the alphabet, and the second printing element group (9-3) shown in FIG. ) Is obtained by removing the characters “OK” from the first printing element group (8-3) from the background element group (4-3).

  FIG. 18 shows respective images formed by the first ink and the second ink. FIG. 18A shows an image formed with the second ink, and has a configuration in which the information element group (5-3) and the second printing element group (9-3) are combined. The image shown in FIG. 18A was printed on the substrate (2-3) by offset printing using the second ink produced with the formulation shown in Table 2. FIG. 18B shows an image formed with the first ink, which is composed of only the first printing element group (8-3). The image shown in FIG. 18B was printed on the substrate (2-3) by offset printing using a DIC offset ink OP varnish “High Gloss”.

  The first ink and the second ink have substantially the same spectral reflectance when printed on the substrate with the same area ratio, and the first ink has a spectral transmittance higher than that of the second ink. Has great properties. Therefore, when the first ink and the second ink are printed on the base material with the same area ratio, they are observed in the same color in the observation under the reflected light, and the first ink in the observation under the transmitted light. The printed image appears brighter than the image printed with the second ink. In the case of Example 3, the integral value of the transmission spectrum in the first printing element group has 140% of the integral value of the transmission spectrum in the second printing element group and the information element group.

  The effect in Example 3 of this invention is demonstrated using FIG. When the latent image printed matter (1-3) of the present invention is observed under reflected light, it is formed with the first printing element group (8-3) formed with the first ink and the second ink. Since the second printing element group (9-3) is visually recognized in almost the same color, the printed image (3-3) composed of the characters “COPY” shown in FIG. However, it can be visually recognized with a density slightly darker than the color of the paper as the substrate (2-3).

  Further, when the latent image printed material (1-3) of the present invention is observed under transmitted light, the second printing element group (9-3) and the information element group (5- 3) is the same color as the skin-colored paper which is the base material (2-3), and the first printing element group (8-3) formed with the first ink includes the base material (2-3) and Since it is viewed brighter than the first printing element group (9-3) and the information element group (5-3) formed with the second ink, the observer sees as shown in FIG. The first printing element group (8-3) consisting of the letters “OK” formed by the first ink is brighter than the base material (2-3).

  As described above, when observed under reflected light, the information element group (5-3) is formed in the background element group (4-3), resulting in a difference in area ratio. When the printed image (3-3) composed of characters is viewed darker than the base material (2-3) and is observed under transmitted light, the printed image (3-3) is composed of characters “OK” formed by the first ink. One printing element group (8-3) is visually recognized brighter than the substrate (2-3). In this way, different images with no correlation were confirmed in observation under reflected light and transmitted light.

  A fourth embodiment of the present invention will be described with reference to FIGS. In Example 4, high-quality white paper (manufactured by Nippon Paper Industries Co., Ltd.) was used as the base material (2-4).

  FIG. 20A shows a latent image printed material (1-4) according to the present invention. In the latent image print (1-4), a print image (3-4) having a color different from that of the base material is formed on the base material (2-4), and the print image (3-4) is: It consists of a background element group (4-4) shown in FIG. 20B and an information element group (5-4) shown in FIG. In the background element group (4-4) shown in FIG. 20B, the elements (6-4) having an image line width of 0.25 mm are regularly arranged at a pitch of 0.5 mm. The information element group (5-4) shown in FIG. 20C is in contact with the element (6-4) forming the background element group (4-4). Elements (7-4) forming an image line with an image line width of 0.25 mm are arranged at a pitch of 0.5 mm, and an area ratio difference is caused by the information element group (4-4). "Is visually recognized. As described above, even when the image is formed by the elements of the line that touches as an element, the element (6-4) forming the background element group (4-4) and the element (5-4) forming the information element group (5-4) ( 7-4) are configured alternately so as not to overlap. That is, the print image (3-4) includes the information element group (5-4) in a flat gradation created by the plurality of elements (6-4) forming the background element group (4-4). ) Is formed, a portion having a higher area ratio than the background element group (4-4) is generated in the arranged portion, and a difference in the area ratio is generated. The characters “COPY” are formed by the portions.

  FIG. 21 shows two element groups constituting the background element group (4-4). FIG. 21A shows the first printing element group (8-4), and FIG. 21B shows the second printing element group (9-4). The first printing element group (8-4) shown in FIG. 21A is a configuration showing the letters “OK” of the alphabet, and the second printing element group (9-4) shown in FIG. ) Has a configuration in which the characters “OK” of the first print element group (8-4) are removed from the background element group (4-4).

  FIG. 22 shows respective images formed by the first ink and the second ink. FIG. 22A shows an image formed with the second ink, which is configured by combining the information element group (5-4) and the second printing element group (9-4). The image shown in FIG. 22A was printed on the substrate (2-4) by offset printing using the second ink produced with the formulation shown in Table 2. FIG. 22B shows an image formed with the first ink, and is composed of only the first printing element group (8-4). The image shown in FIG. 22B was printed on the substrate (2-4) by offset printing using a DIC offset ink OP varnish “high gloss”.

  The first ink and the second ink have substantially the same spectral reflectance when printed on the substrate with the same area ratio, and the first ink has a spectral transmittance higher than that of the second ink. Has great properties. Therefore, when the first ink and the second ink are printed on the base material with the same area ratio, they are observed in the same color in the observation under the reflected light, and the first ink in the observation under the transmitted light. The printed image appears brighter than the image printed with the second ink. In the case of Example 4, the integral value of the transmission spectrum in the first printing element group has 140% of the integral value of the transmission spectrum in the second printing element group and the information element group.

  The effect in Example 4 of this invention is demonstrated using FIG. When the latent image printed matter (1-4) of the present invention is observed under reflected light, it is formed with the first printing element group (8-4) formed with the first ink and the second ink. Since the second print element group (9-4) is visually recognized in almost the same color, the printed image (3-4) including the characters “COPY” shown in FIG. However, it can be visually recognized at a density slightly darker than the color of the paper as the base material (2-4).

  When the latent image print (1-4) of the present invention is observed under transmitted light, the second print element group (9-4) and the information element group (5- 4) is the same color as the skin-colored paper which is the base material (2-4), and the first printing element group (8-4) formed with the first ink includes the base material (2-4) and Since it is viewed brighter than the first printing element group (9-4) and the information element group (5-4) formed with the second ink, the observer sees as shown in FIG. The first printing element group (8-4) consisting of the letters “OK” formed by the first ink is visible brighter than the substrate (2-4).

  As described above, when observed under reflected light, the information element group (5-4) is formed in the background element group (4-4), resulting in a difference in area ratio. When the printed image (3-4) composed of characters is viewed darker than the base material (2-4) and is observed under transmitted light, the printed image (3-4) composed of characters “OK” formed by the first ink is used. One printing element group (8-4) is visually recognized brighter than the substrate (2-4). In this way, different images having no correlation were observed in observation under reflected light and transmitted light.

  A fifth embodiment of the present invention will be described with reference to FIGS. In Example 5, general white-quality fine paper (manufactured by Nippon Paper Industries Co., Ltd.) was used as the base material (2-5).

  FIG. 24A shows a latent image printed material (1-5) according to the present invention. In the latent image print (1-5), a print image (3-5) having a color different from that of the base material is formed on the base material (2-5), and the print image (3-5) is: It consists of a background element group (4-5) shown in FIG. 24B and an information element group (5-5) shown in FIG. In the background element group (4-5) shown in FIG. 24 (b), the elements (6-5) having a halftone dot having a diameter of 0.25 mm are regularly arranged at a pitch of 0.5 mm. The information element group (5-5) shown in FIG. 24C is finer and more difficult to see than the element (6-5) forming the background element group (4-5). It is formed by elements (7-5) expressing gradations by various halftone dots, and an area ratio difference is generated by the information element group (4-5), which is visually recognized as a “butterfly” image. As described above, even when the elements are formed with gradation, the elements (6-5) forming the background element group (4-5) and the elements (7) forming the information element group (5-5) are used. -5) is configured not to overlap. That is, the print image (3-5) includes the information element group (5-5) in the flat gradation created by the plurality of elements (6-5) forming the background element group (4-5). ) Forming the element (7-5), a portion having a higher area ratio than the background element group (4-5) is generated in the arranged part, and a difference in the area ratio is generated. An image of “butterfly” is formed by the portion.

  FIG. 25 shows two element groups constituting the background element group (4-5). FIG. 25A shows the first printing element group (8-5), and FIG. 25B shows the second printing element group (9-5). The first printing element group (8-5) shown in FIG. 25A is a configuration showing the letters “OK” of the alphabet, and the second printing element group (9-5) shown in FIG. ) Has a configuration in which the characters “OK” of the first print element group (8-5) are removed from the background element group (4-5).

  FIG. 26 shows respective images formed by the first ink and the second ink. FIG. 26A shows an image formed with the second ink, and has a configuration in which the information element group (5-5) and the second printing element group (9-5) are combined. The image shown in FIG. 26A was printed on the substrate (2-5) by offset printing using the second ink prepared with the formulation shown in Table 2. FIG. 26B shows an image formed with the first ink, which is composed of only the first printing element group (8-5). The image shown in FIG. 26B was printed on the substrate (2-5) by offset printing using a DIC offset ink OP varnish “high gloss”.

  The first ink and the second ink have substantially the same spectral reflectance when printed on the substrate with the same area ratio, and the first ink has a spectral transmittance higher than that of the second ink. Has great properties. Therefore, when the first ink and the second ink are printed on the base material with the same area ratio, they are observed in the same color in the observation under the reflected light, and the first ink in the observation under the transmitted light. The printed image appears brighter than the image printed with the second ink. In the case of Example 5, the integral value of the transmission spectrum in the first printing element group has 140% of the integral value of the transmission spectrum in the second printing element group and the information element group.

  The effect in Example 5 of this invention is demonstrated using FIG. When the latent image print (1-5) of the present invention is observed under reflected light, it is formed with the first printing element group (8-5) formed with the first ink and the second ink. Since the second printing element group (9-5) is visually recognized to be substantially the same color, the printed image (3-5) including the image of the “butterfly” shown in FIG. However, it can be visually recognized with a density slightly darker than the color of the paper as the substrate (2-5).

  When the latent image printed material (1-5) of the present invention is observed under transmitted light, the second printing element group (9-5) and the information element group (5- 5) is the same color as the skin-colored paper which is the base material (2-5), and the first printing element group (8-5) formed with the first ink includes the base material (2-5) and Since it is viewed brighter than the first printing element group (9-5) and the information element group (5-5) formed with the second ink, as shown in FIG. The first printing element group (8-5) composed of the characters “OK” formed by the first ink is visible brighter than the base material (2-5).

  As described above, when observed under reflected light, a difference in area ratio is generated by forming the information element group (5-5) in the background element group (4-5). When the printed image (3-5) composed of the image is viewed darker than the base material (3-5) and observed under transmitted light, the printed image (3-5) is composed of the first “OK” character formed by the first ink. One printing element group (8-5) is visually recognized brighter than the substrate (2-5). In this way, different images with no correlation were confirmed in observation under reflected light and transmitted light.

1, 1-1, 1-2, 1-3, 1-4, 1-5 Latent image printed matter 2, 2-1, 2-2, 2-3, 2-4, 2-5 Base material 3, 3 -1, 3-2, 3-3, 3-4, 3-5 Print image 4, 4-1, 4-2, 4-3, 4-4, 5-5 Background element group 5, 5-1, 5-2, 5-3, 5-4, 5-5 Information element groups 6, 6-1, 6-2, 6-3, 6-4, 6-5 Elements 7 and 7- forming a background element group 1, 7-2, 7-3, 7-4, 7-5 Elements 8, 8-1, 8-2, 8-3, 8-4, 8-5 forming an information element group First printing element Group 9, 9-1, 9-2, 9-3, 9-4, 9-5 Second printing element group 10R Spectral reflectance curve 11R of the first print sample Spectral reflectance curve of the second print sample 12R Spectral reflectance curve of substrate 10T Spectral transmittance curve of first print sample 11T Second Spectral transmittance curve of the spectral transmittance curve 12T substrate printed sample

Claims (5)

In a latent image printed matter comprising a printed image on at least a part of a substrate,
The printed image is information formed by arranging a plurality of elements so as not to overlap with a background element group formed with a certain area ratio formed by arranging a plurality of elements and the elements forming the background element group. A group of elements,
The background element group is divided into a first print element group and a second print element group,
The first printing element group is formed of a first ink, the second printing element group and the information element group are formed of a second ink,
The spectral reflectance of the first printing element group has a spectral reflectance equal to the spectral reflectance of the second printing element group, and the spectral reflectance of the first printing element group, the second The spectral reflectance of the printing element group and the spectral reflectance of the information element group have a spectral reflectance lower than the spectral reflectance of the substrate,
The first printing element group has a spectral transmittance higher than the spectral transmittance of the second printing element group and the spectral transmittance of the information element group, and the second printing element group. And the spectral transmittance of the information element group has a spectral transmittance equal to the spectral transmittance of the substrate,
A latent image printed matter, wherein the first printed element group is visually recognized when observed under transmitted light, and the printed image is visually observed when observed under reflected light.   The latent image printed matter according to claim 1, wherein the elements forming the background element group are pixels and / or image lines.   The latent image printed matter according to claim 1, wherein the elements forming the information element group are pixels and / or image lines.   In the wavelength range of 400 nm to 700 nm, the integral value of the transmission spectrum in the first printing element group has 120% or more of the integral value of the transmission spectrum in the second printing element group and the information element group. The latent image printed matter according to any one of claims 1 to 3.   The latent image printed matter according to claim 1, wherein the first ink and / or the second ink is a mixture of functional materials.

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