JP2012061775A - Printing medium having transmissive latent image - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a printed matter having a latent image to be applied to prevent forgery and duplication on banknotes, passports, securities, product tags and various certificates.
A concealing layer for suppressing the permeability of a base material is laminated on a base material made of a permeable material, and further, a first coloring material is used so as to form an image-like shape thereon. An image forming layer is formed using the element, the cutout portion or the second element having a highly transparent colored material and the third element having an infrared absorbing dye, and the element width of each element in the image forming layer is determined. A partially different image is formed, a visible image by the first element, a first latent image that is visible when the substrate by the second element is confirmed under transmitted light, and an infrared by the third element It is a printed matter having a second latent image that is visible when confirmed under a light source.
[Selection] Figure 1

Description

  The present invention is intended for banknotes, passports, securities, product tags, various certificates, and particularly cards such as ID cards, three different images, images under reflected light, images under transmitted light, and The present invention relates to a print medium that makes it difficult to forge and duplicate by forming an image under an infrared light source.

  In recent years, counterfeit products of valuable printing media such as banknotes, passports, and securities have become a serious problem due to the high functionality and high image quality of copiers. For this reason, various techniques have been developed for valuable print media so that they cannot be reproduced by a copying machine. As one of them, there is a technology that exhibits a copy prevention effect and a watermark effect under transmitted light by forming an image using a transparent or translucent substrate.

  For example, a first printed layer, a concealing layer, and a second printed layer are laminated on one side of a transparent or translucent substrate, and an opening that penetrates from the second printed layer to the first printed layer is provided. An anti-counterfeit print medium in which a display unit composed of a dot-like or halftone dot-like pattern is formed is disclosed (for example, see Patent Document 1).

  In the anti-counterfeit print medium described in Patent Document 1, the opening other than the pattern is a transparent watermark that exposes the base material. Reproducibility is difficult, and in particular, a special authenticity determination device is not required, and since authenticity can be easily discriminated by visual observation under transmitted light, there is high discrimination between a genuine product and a duplicate product. In addition, it is also possible to use an ink mixed with a magnetic material, an ink containing two or more kinds of metallic materials, or a combination of various functional inks for the printing layer. Thus, it is possible to achieve a further anti-counterfeit effect.

  Other techniques relating to copying and anti-counterfeiting include the use of functional inks that are difficult to reproduce such as color, gloss, or light emission. Functional inks include magnetic inks, fluorescent inks, and infrared absorbing inks that exhibit absorption characteristics in the infrared region. Precious print media using these functional inks are effective for copying on a copier, but for simple characters and designs, if materials are available, they can be forged relatively easily. There is a problem of being able to.

  Therefore, the present applicant not only uses functional ink, but also has a high-definition line drawing configuration, so that a visible image and a forgery image that can be seen only under specific observation conditions can appear. The prevention printed matter is proposed (for example, refer patent document 2).

  The anti-counterfeit printed matter described in Patent Document 2 is composed of a first image line and a second image line, and the first image line is formed of infrared absorbing ink and has two image line widths W1 and W2. have. A visible image is formed by an image line having an image line width W1. The second image line is formed of infrared transmission ink and has two image line widths W3 and W4. A latent image is formed by an image line having an image line width W3. The second image line is formed on the first image line, and the image line widths have a relationship of W1> W2 ≧ W3> W4. Further, it is assumed that the first image line and the second image line are visually recognized in the same color under a visible light source.

  In the anti-counterfeit printed matter of Patent Document 2, only a visible image formed by an image line having an image line width W1 in the first image line is visible under a visible light source. Furthermore, when the image is observed using a discrimination device such as an infrared camera, the first image line cannot be observed, and is newly formed by the image line having the image line width W3 in the second image line. A latent image can be observed.

  Further, a planar image of three or more layers is formed in the transparent region, and the transparent region is laminated with a transparent substrate sheet provided with the planar image on one side or both sides. An anti-counterfeit carrier made of an absorbing material and an infrared transmitting material is disclosed (for example, see Patent Document 3).

  Since the anti-counterfeit carrier described in Patent Document 3 is a transparent base sheet, it is possible to visually recognize the planar images formed on the laminated layers in a synthesized state. If a discrimination device capable of reading an infrared image is used, it is possible to confirm only a planar image formed using an infrared absorbing material and an infrared transmitting material.

Japanese Patent Application Laid-Open No. 10-76745 JP 2008-265189 A JP 2006-68987 A

  However, the print medium described in Patent Document 1 has a transparent watermark formed by having an opening penetrating from the second print layer to the first print layer. Therefore, the print medium is transparent under transmitted light. It is possible to easily determine whether it is true or not, but the transparent watermark by the opening is a simple pattern, and once the layer structure is known, it can be forged and imitated relatively easily. There was a problem of being able to do it.

  In addition, the transparent watermark by the opening is a simple pattern and does not form a design having a continuous tone, so that it is desired to form a design with a high design. .

  Furthermore, when confirming a transparent watermark under transmitted light, the pattern and visible information formed on the second printed layer can be visually recognized together, and can be visually recognized as individual images. Therefore, since it did not produce an image switching effect (switching effect), a further advanced anti-counterfeiting technology was demanded.

  Further, the anti-counterfeit printed matter described in Patent Document 2 has a special line drawing configuration and inexpensively displays two images, a visible image recognizable with visible light and a latent image recognizable with a discrimination device such as an infrared camera. We were able to achieve that. However, since the latent image cannot be viewed without using a discrimination device such as an infrared camera, for example, inspectors in various window operations such as banking, immigration examination, etc. There was a problem that could not be done. Therefore, there is a need for a forgery-preventing printed matter that is provided with a technique capable of determining authenticity by visual observation without using a special determination device in addition to appraisal authenticity determination using a special determination device.

  In addition, the anti-counterfeit carrier described in Patent Document 3 is formed by laminating a transparent base sheet and forming a planar image on each layer, so that each planar image formed on each layer is synthesized. Since the viewing state of the planar image of each layer can be changed by tilting the viewing angle, it is possible to discriminate by visual observation, and at least one planar image is formed. Since the layer is formed using an infrared absorbing material and an infrared transmitting material, by using a discrimination device that can read an infrared image, appraisal authenticity discrimination can also be performed, and visual discrimination and appraisal using a discrimination device However, since the planar image formed on the transparent base sheet is a simple pattern, if the layer configuration is known, Manner easily there is a possibility that the forged.

  Furthermore, for an infrared image that can be viewed under an infrared light source, a plane image of one layer may be formed using an infrared absorbing material and an infrared transmitting material, and the material for forming an image is simply a function. Since it has the problem that the same image can be formed if only the material can be obtained, obtain a material with special functionality. Even if it can be done, there has been a demand for a print medium with higher security that has a configuration in which the same image or the like cannot be easily formed.

  The present invention aims to solve the above-mentioned problems, and makes it difficult to forge and duplicate by using a precise image line configuration, and it is easy to use under transmitted light without using a special discrimination device. A print medium having a latent image that can be confirmed is proposed. It is another object of the present invention to propose a print medium capable of performing two different types of discrimination, that is, a latent image that can be checked for authenticity using a discrimination device in addition to discrimination under transmitted light.

  According to the present invention, a transmission latent image region is formed on a part of a substrate made of a transparent material, and the transmission latent image region on the substrate is formed of at least a part of a colorless and / or colored transparent material. Is formed with a concealing layer made of a concealing material for suppressing the permeability of the permeable material, and i) the concealing layer is obtained from the first concealment area ratio where the concealing material for concealing the permeability of the substrate is applied. A first concealing area and a hollow area that is not coated with a concealing material to partially expose the substrate, or ii) the concealing layer is a first concealment area ratio that conceals the permeability of the substrate. And a second concealment region composed of a second concealment area ratio lower than the first concealment area ratio, and a plurality of first elements and first layers on the concealment layer. 2 elements are arranged in a line to form an image forming layer The plurality of first elements are divided into a first pattern portion and a first background portion by partially varying the element width depending on the colored color material to form a visible image, and the concealment layer is a hollow region. In the case of i), a second area where no colored coloring material is applied is formed in the first element, and the second pattern is obtained by partially varying the element width in the second area. The cutout area and the second area are arranged at the same place, and a plurality of second areas are arranged to form a first latent image, and the concealment layer is the second background area. In the case of ii) having a concealed area, a second element having a transmittance of 3% or more and 100% or less is formed by a colored coloring material in the first element, and the element width of the second element is increased. It is divided into the second pattern part and the second background part by making it partially different, and the second concealment area and The second element is arranged at the same location, and a plurality of the second elements are arranged to form a first latent image, so that the first element and the second element have the same color in the diffused light region. By forming the transparent latent image, a visible image is visually recognized in the diffused light region under the visible light source, and the first latent image is visible when the substrate is observed under the transmitted light. It is a print medium.

  In the case of i) in which the concealing layer has a cutout region, the print medium having a transmission latent image of the present invention has the same shape and size, or the concealment layer has a concealment layer. In the case of ii) having the second concealment region, the second concealment region and the second element are characterized by having the same shape and size.

  In the present invention, a transmission latent image region is formed on a base material which is at least partially made of a colorless and / or colored transmission material and contains an infrared absorbing dye or does not contain an infrared absorbing dye. In the latent image area, there is formed a concealing layer made of a concealing material that does not contain an infrared absorbing dye and suppresses the transmissivity of the translucent material, and iii) the concealing layer conceals the transparency of the substrate. A first concealment region comprising a first concealment area ratio provided with a concealment material and a cutout region not provided with a concealment material to partially expose the substrate, or iv) the concealment layer comprises a base A first concealment area composed of a first concealment area ratio provided with a concealment material concealing the permeability of the material, and a second concealment area composed of a second concealment area ratio lower than the first concealment area ratio Formed by A plurality of first elements, second elements, and third elements are arranged in a line on the covering layer to form an image forming layer. The plurality of first elements include an infrared absorbing dye. The first element is divided into a first pattern part and a first background part by partially varying the element width by a non-colored color material, and v) the third element is a color material containing an infrared absorbing dye, Arranged so as to overlap within the first element, or vi) the third element is partially overlapped with the first element by a colored coloring material containing an infrared absorbing dye, and the first element The second latent image is formed in a direction different from the element and divided into a third pattern portion and a third background portion by partially changing the element width of the third element. In the case of iii) having a hollow area, the base material contains an infrared absorbing dye, and a colored coloring material is applied in the third element. A second element is formed, and the second element is divided into a second pattern portion and a second background portion by partially varying the element width, and the cutout region and the second element are located at the same location. In the case of iv) in which the first latent image is formed by arranging a plurality of second elements and the concealing layer has the second concealment region, the second element is the third element In the element, it is arranged so as to overlap with the same location as the second concealed region, and when the substrate contains an infrared absorbing dye, the transmittance is 3% or more and 100% or less, and it contains or does not contain the infrared absorbing dye If the substrate does not contain an infrared absorbing dye, the transmittance is 3% or more and 100% or less, and the colored material containing the infrared absorbing dye is used to form an element width. The second pattern and the second background can be changed In the case of v) in which the first latent image is segmented to form the third element and the third element is arranged so as to overlap the first element, the first pattern portion and the first background portion are visible. In the case of vi) in which an image is formed or the third element is partially overlapped with the first element, the first pattern portion, the third background portion, and the first background portion A visible image having the same density of the third pattern portion is formed, and the first element, the second element, and the third element are formed so as to have the same color in the diffused light region. In the diffused light region, a visible image is visually recognized. When the substrate is observed under infrared light, the second latent image is visually recognized. Further, when the substrate is observed under transmitted light, the first latent image is visible. This is a printing medium having a transmission latent image.

  Further, in the case of the printing medium having a transmission latent image of the present invention in which the concealing layer has a hollow area iii), the hollow area and the second element have the same shape and size, or the concealing layer has In the case of iv) having the second concealment region, the second concealment region and the second element are characterized by having the same shape and size.

  In the printing medium having a transmission latent image of the present invention, the third element is partially overlapped with the first element by a colored color material containing an infrared absorbing dye, and the first element and Are iv) arranged in different directions, the element width of the first element forming the first pattern part and the element of the third element forming the third background part The width is equal, and the element width of the first element forming the first background portion is equal to the element width of the third element forming the third pattern portion.

  In the printing medium having a transmission latent image of the present invention, the third element is partially overlapped with the first element by a colored color material containing an infrared absorbing dye, and the first element and Is the case of iv) arranged in different directions, wherein the pattern formed by the first element and the third pattern portion have the same shape and size and are formed at the same position And

  The print medium having a transmission latent image according to the present invention is characterized in that the first element, the second element, and the third element are all arranged at the same first pitch.

  In the printing medium having a transmission latent image according to the present invention, the first element, the second element, and the third element may be composed of at least one of an image line or a group of microelements, or a combination of each. Features.

  The printing medium having a transmission latent image of the present invention is characterized in that the color material containing the infrared absorbing dye is a colored ink containing a material having at least one absorption peak in the infrared region.

  The printing medium having a transmission latent image of the present invention is characterized in that the color material not containing an infrared absorbing dye is a colored ink of cyan, magenta and yellow, or a single color special color ink.

  The print medium having the transmission latent image of the present invention can visually recognize the visible image when observed under a visible light source, and can visually recognize the first latent image when the print medium is observed under transmitted light. When observed under an infrared light source, the second latent image is visible. That is, it is possible to form three images with different viewing conditions on a single print medium. In particular, each image can be switched (confirmed by switching images) under different viewing conditions. .

  In addition, since the print medium having the transmission latent image of the present invention can confirm the image under transmitted light, the authenticity determination can be performed by a simple visual method and an infrared image can be acquired. Therefore, both simple discrimination and appraisal discrimination can be performed.

  In addition, the print medium having a transmission latent image of the present invention can be easily produced in a design in which three images are overlapped in the same region by a special image line configuration, and is subject to design restrictions. Therefore, a gradation image can be formed.

It is a figure which shows an example of the printing medium which has a permeation | transmission latent image. It is a figure which shows an example of a visible image and a 1st latent image. It is a figure for demonstrating the layer structure of a transmission latent image area | region. It is a figure for demonstrating the aspect of the concealment layer in the 1st aspect of 1st Embodiment. It is an example of the top view and schematic diagram which show the transmission latent image area | region in the 1st aspect of 1st Embodiment. It is a figure which shows an example of the element in connection with this invention. It is a figure which shows an example which makes a part of element width in connection with this invention differ. It is a figure for demonstrating the layer structure of the three layers in the 1st aspect of 1st Embodiment. It is the figure which showed three positional relationships of the printing medium which has the transmission latent image image formed by the 1st aspect of 1st Embodiment, a visible light source, and a viewpoint. It is a graph which shows color difference (DELTA) E of each 1st element and 2nd element under reflected light (diffuse light) and transmitted light. It is the top view and schematic diagram at the time of visually recognizing the printing medium formed by the 1st aspect of 1st Embodiment under the reflected light (diffuse light) under the visible light source (R) of a fixed position. . It is the top view and schematic diagram at the time of visually recognizing the printing medium formed by the 1st aspect of 1st Embodiment under the transmitted light under the visible light source of a fixed position. It is a schematic diagram which shows the structure of the concealment layer of the 2nd aspect of 1st Embodiment. It is a schematic diagram which shows the structure of the image forming layer of the 2nd aspect of 1st Embodiment. It is a figure for demonstrating the layer structure of the three layers of the 2nd aspect of 1st Embodiment. It is a schematic diagram which shows the structure of the image forming layer of the 3rd aspect of 1st Embodiment. It is a figure for demonstrating the layer structure of the three layers of the 3rd aspect of 1st Embodiment. It is a figure for demonstrating the aspect of the concealment layer in the 1st aspect of 2nd Embodiment. It is an example of the top view and schematic diagram which show the transmission latent image area | region of 2nd Embodiment. It is a figure for demonstrating the layer structure of the three layers in the 1st aspect of 2nd Embodiment. It is a graph which shows an example of the spectral transmittance of white ink and magenta ink. It is a graph which shows an example of the spectral reflectance of PET film, white ink, magenta ink, and black ink. It is the top view and schematic diagram at the time of visually recognizing the printing medium formed by the 1st aspect of 2nd Embodiment under the reflected light (diffuse light) under the visible light source (R) of a fixed position. . It is the top view and schematic diagram at the time of visually recognizing the printing medium formed by the 1st aspect of 2nd Embodiment under the transmitted light under the visible light source of a fixed position. It is the top view and schematic diagram at the time of observing the printing medium formed by the 1st aspect of 2nd Embodiment through apparatuses, such as an infrared display device, under the infrared light source of a fixed position. It is a figure for demonstrating the aspect of the concealment layer in the 2nd aspect of 2nd Embodiment. It is a schematic diagram which shows the structure of the image forming layer of the 2nd aspect of 2nd Embodiment. It is a figure for demonstrating the layer structure of the three layers in the 2nd aspect of 2nd Embodiment. It is a schematic diagram which shows the structure of the image forming layer of the 3rd aspect of 2nd Embodiment. It is a figure for demonstrating the layer structure of the three layers in the 3rd aspect of 2nd Embodiment. It is a schematic diagram which shows the modification of the element structure which concerns on this invention. It is an example of the top view and schematic diagram which show the transmission latent image area | region of 3rd Embodiment. It is a figure explaining the layer structure of a permeable material. 3 is a diagram for explaining a layer configuration of three layers in Example 1. FIG. It is a figure explaining the certificate of Example 2. FIG. It is a figure which shows the visible image in Example 2, a 1st latent image, and a 2nd latent image. 6 is a diagram for explaining a layer configuration of three layers in Example 2. FIG.

  Embodiments of the present invention will be described with reference to the drawings. However, the present invention is not limited to the embodiments to be described below, and various other embodiments can be implemented within the scope of the technical idea described in the claims.

  FIG. 1 is a diagram showing an example of a print medium (1) (hereinafter referred to as “print medium”) having a transmission latent image in the present invention. As shown in FIG. 1A, the print medium (1) has a transmission latent image region (2) in which a transmission latent image according to the present invention is formed at least partially.

  This print medium (1) can visually recognize a visible image (3) as shown in FIG. 2 (a) under reflected light (diffused light) under a visible light source, and under transmitted light under a visible light source. The first latent image (4) as shown in FIG. 2 (b) can be visually recognized. The principle of visual recognition of these two images will be described later.

  The transmission latent image region (2) is composed of three layers as shown in FIG. 1 (b) which is a cross-sectional view of the print medium (1). The transmission latent image region (2) may be formed on a part of the print medium (1) as shown in FIG. 1, but the entire surface of the print medium (1) is formed as the transmission latent image region (2). You may do it. For the three layers constituting the transmission latent image region (2), the base material (7), the concealing layer (8), and the image forming layer (9) are formed in order from the bottom layer. ing. These three layers will be described next.

  First, the base material (7) will be described. The base material (7) is formed using a transparent material (6) that is at least partially colorless and / or colored. As the colorless (transparent) transparent base material, there is a transparent film formed of a material such as PET or vinyl chloride. In addition, as the colored transparent base material, there are those obtained by adding coloring components such as dyes and pigments to the above-mentioned colorless (transparent) PET film and the like, and transparent colored inks and colored films are laminated. It may be formed. An example of the layer structure of the permeable material will be described later.

  Further, a transparent metallic glossy film (such as PICASUS manufactured by Toray Industries, Inc.) may be used for the base material (7). The metallic glossy film is a polyester film formed by laminating different kinds of polymers and is a transmissive material capable of obtaining a metallic gloss without using a metal.

  In FIG. 1B, the entire surface of the print medium (1), that is, the base material itself is described as being formed of a transparent material. However, the base material (7) of the present invention is not limited to this. Alternatively, a part of the base material (7) may be formed of a permeable material.

  For example, as shown in FIG. 3, the transmissive material (6) may be formed only in a portion corresponding to the transmission latent image region (2).

  Next, the concealment layer (8) which is the second layer will be described. The concealment layer (8) is formed on the base material (7) formed of the above-described permeable material, and plays a role in suppressing the permeability of the base material (7) as the lower layer. The hiding layer (8) needs to have a color that does not affect the visible image (3) formed by the image forming layer (9) formed on the hiding layer (8). Therefore, although the concealing layer (8) can use white ink or the like, it is a concealing material capable of suppressing the transparency of the base material (7) and affects the visible image (3) of the image forming layer (9). The material is not particularly limited as long as the material does not give any. In the present embodiment, description will be made by forming using white ink. Examples of the white ink include Dicure RTX white manufactured by DIC Corporation as UV ink for offset printing, and LIOJET FV03 White manufactured by Toyo Ink Manufacturing Co., Ltd. as UV ink for inkjet printing.

  FIG. 4A is a schematic diagram in which a part of the concealment layer (8) is enlarged, but the concealment layer (8) corresponds to a third image forming layer (9) described later. , Formed from one region. As described above, this region has a role of concealing the transparency of the base material (7) as a lower layer, and is therefore defined as a first concealment region (11) having a first concealment area ratio. Moreover, the area | region which does not form a concealment material is defined as a hollow area | region (10), and since the concealment material is not formed in this hollow area | region (10), it will be in the state which the base material (7) exposed. In addition, the description about the concealment area ratio is mentioned later.

  The positional relationship, shape, and size of the first concealment region (11) constituting the concealment layer (8) correspond to the element configuration of the image forming layer (9). The corresponding relationship between the concealment layer (8) and the image forming layer (9) will be described when explaining the visual recognition principle described later. Further, in the present invention, an element is a group of minute elements composed of an image line and / or a dot or a pixel, and a specific description will be given later.

  The cutout region (10) will be described. The hollow region (10) is formed in the first concealment region (11), and as shown in FIG. 4 (b) which is an (enlarged) cross-sectional view at Z1-Z2 in FIG. 4 (a), White ink is not applied to the cutout region (10). Therefore, when the print medium (1) is observed from above, the base material (7) under the concealment layer (8) can be confirmed from the cutout region (10).

  This cut-out area (10) is also arranged corresponding to the element configuration of the image forming layer (9) described later, and in the present invention, a first latent image that can be confirmed under transmitted light is formed. Has become an important role. The positional relationship with the image forming layer (9) will be described later.

  Next, the image forming layer (9) which is the third layer will be described. The image forming layer (9) is to form a visible image (3) including a continuous tone image that is visible under reflected light (diffused light) under a visible light source. Therefore, the element configuration of the image forming layer (9) will be described with reference to FIG. Note that the visible image (3) including the continuous tone image may be a binary image having no continuous tone.

(First aspect of the first embodiment)
FIG. 5 is an example of a plan view and a schematic view showing the transmission latent image region (2) of the first aspect of the first embodiment. As shown in FIG. 5A, the print medium (1) of the present invention is visible in at least a part of the transmission latent image region (2) on the base material (7) made of a transmission material such as a plastic card. An image (3) is formed by printing. The visible image (3) is a concealing material for suppressing the transparency of the commonly used cyan (C), magenta (M), yellow (Y) and black (Bk) inks and the above-described transmissive materials. It is formed with a certain white ink. The visible image (3) is generated by superposing two images composed of lines on the same plane so as to overlap each other with a special line structure. The special image line configuration will be described later.

  In the transmission latent image region (2) shown in FIG. 5A, a visible image (3) and a first latent image (4) that is a latent image are formed. The first latent image (4) is embedded in the visible image (3), and the visible image (3) is visible under reflected light (diffused light) under a visible light source, but transmitted light. Below, it becomes possible to visually recognize the first latent image (4). The transmission latent image region (2) of the present invention shown in FIG. 5A is referred to as a normal viewing condition (hereinafter referred to as “first viewing condition”) under a visible light source by the element configuration shown in FIG. ) And a visual recognition condition (hereinafter referred to as “second visual recognition condition”) in which the base material (7) is seen through the light source under a visible light source, the different patterns can be visually recognized.

  When the transmission latent image region (2) shown in FIG. 5 (a) is observed under reflected light (diffused light) under a visible light source, as shown in FIG. 5 (c1), a visible image (3) Can be visually recognized. Further, when the substrate (7) is seen through the visible light source under the visible light source, that is, when the transmission latent image region (2) shown in FIG. 5 (a) is observed under the transmitted light under the visible light source. As shown in FIG. 5 (c2), it can be visually recognized as the first latent image (4). As described above, the visible image (3) shown in FIG. 5A has different patterns that appear by changing the observation conditions. The visual recognition principle will be described later.

  Here, an element structure is demonstrated using the schematic diagram of FIG.5 (b). As shown in FIG. 5 (b), the visible image (3) is formed on the concealment layer (8) formed on the base material (7) on the first element (14) and the image forming layer (9). It is formed by a second element (15).

  A plurality of first elements (14) are arranged at a first pitch (d1) in the first direction (X). In the first element (14), the second element (15) is arranged so as to overlap. The visible image (3) is formed by changing the element width or area ratio of each element within a predetermined range. In addition, the arrangement | positioning location of the 1st element (14) and the 2nd element (15) in a visible image (3) is not limited to this, The aspect of another form is mentioned later. The “predetermined range” here will be described later.

  An element in the present invention is a plurality of lines or dots or pixels arranged in a line. FIG. 6 is a diagram illustrating an example of elements. The drawing line is, for example, a straight line shown in FIG. 6A, a broken line shown in FIG. 6B, a wavy line shown in FIG. 6C, or a broken wavy line shown in FIG. The shade of the printed part is reproduced by the width of the width. The line width is generally 30 to 1000 μm. A plurality of points arranged in a line form are points formed on a printed material by a mesh screen, a contact screen or the like, and the density of the printed material is reproduced by the size of this point. Since a plurality of points arranged in a line form are a collection of minute points, they are visually recognized as one line by the naked eye. The shape of the dot is not limited to a circular dot, and random dots and a special halftone dot generation method proposed in Japanese Patent Application Laid-Open No. 11-268228 previously filed by the present applicant are taken into account. A special halftone dot shape having a degree of freedom obtained by converting the input image into a continuous tone halftone dot composed of a halftone screen may be used.

  A plurality of pixels arranged in a line is a minimum unit obtained by dividing a two-dimensional image such as a figure or a character by vertical and horizontal lines. The pixel shape is, for example, a circular shape as shown in FIG. 6E, an elliptical shape (not shown), a rectangular shape shown in FIG. 6E, or a polygonal shape such as a triangular shape shown in FIG. It is also good. The pixels may be arranged at different angles as shown in FIG. 6 (g). Furthermore, as shown in FIG. 6H, a character shape may be used. In that case, in order to enhance the forgery prevention effect, the character fonts may be arranged differently as shown in FIG. The character shape shown in FIG. 6H is generally called a minute character or a special halftone dot, but is a pixel in the present invention. In addition, since a plurality of pixels arranged in a line form is an aggregate of minute pixels, it is visually recognized as one line by the naked eye. In the present invention, a group in which these elements are formed by a collection of minute points and pixels is defined as a “minute element group”. Therefore, the elements shown in FIGS. 6E to 6H are formed by the microelement group of the present invention.

  Further, as shown in FIG. 6 (i), two or more types of drawing lines are combined, such as a wavy line and a broken wavy line, or as shown in FIG. 6 (j), a character shape, a circular shape and a rectangular shape are used. For example, two or more types of pixels may be combined. Furthermore, a combination of two or more of a plurality of point groups and pixel groups arranged linearly as shown in FIGS. 6A to 6J may be used. In addition, about 1st Embodiment, an element is demonstrated as a drawing line.

  FIG. 7 is a diagram illustrating an example of changing the element width or the area ratio within a predetermined range. As shown in FIG. 7A, changing the element width or the area ratio within a predetermined range of the image line means changing the image line width within the predetermined range (L1). Further, as shown in FIG. 7B, changing the element width or the area ratio within a predetermined range of a plurality of points arranged in a line form means that the points arranged in a line form are changed in a predetermined range (L1). , To make the size of the points different. Further, as shown in FIG. 7C, changing the element width or the area ratio within a predetermined range of the pixels means changing the number of pixels within the predetermined range (L1). In addition, since the element configuration described above is described as an image line, changing the element width or area ratio within a predetermined range means that the image line width is varied within the predetermined range. Here, the “predetermined range” refers to a range in which the width of an element is changed so that each image to be formed is set, and may be set as appropriate according to the shape of the image to be formed.

  FIG. 5C1 is a diagram illustrating an example of a visible image (3) and a first element (14) that forms the visible image. A plurality of first elements (14) are arranged to form a visible image (3) that is visible under reflected light (diffused light) under a visible light source. The visible image (3) is formed by arranging a plurality of first elements (14) at the first pitch (d1) in the first direction (X). The visible image (3) is obtained by changing the image line width within the predetermined range in the first element (14) to a maximum image line width (W1) and a minimum image line width (W2). Are divided into a pattern portion (14a) and a first background portion (14b). The first pattern portion (14a) is a region for forming a character “A”, and the first background portion (14b) is a region for forming a background other than a region for forming a character “A”. The first element (14) is formed using a colored color material.

  In the first embodiment, the second element (15) is configured in the first element (14). The first element (14) and the second element (15) are visible in the same color under reflected light (diffused light) under a visible light source, so that only the first element (14) is visible. . Thereby, under the reflected light (diffused light) under the visible light source, only the visible image (3) composed of the first element (14) is visible with the naked eye.

  The color matching in the present invention means that the color difference ΔE is less than 6. Generally, when the color difference ΔE is around 6, there is a possibility that the difference is visually recognized. However, as described above, in the present invention, the first element (14) and the second element (15) are configured with an image line width that cannot be visually recognized by distinguishing each region. Therefore, as described above, if the color difference ΔE is less than 6, the second element (15) cannot be visually recognized in the diffuse light reflection region under the visible light source, and the first element (14) and the second element (15) are visible as the same color.

The color difference in the present invention is defined by ΔE in the CIE 1976 L ^* a ^* b ^* color system. The CIE 1976 L ^* a ^* b ^* color system is a color space recommended by the CIE (International Lighting Commission) in 1976, and is defined in JIS Z 8729 in the Japanese Industrial Standards. The color difference is a distance in a color space between two colors, and the color difference in the CIE 1976 L ^* a ^* b ^* color system is the difference between the L ^* difference, the a ^* difference, and the b ^* difference between the two colors. It can be obtained by adding each squared and taking the square root.

  The color difference ΔE changes, for example, by producing a printing ink and applying it as a printing part on a base material using a transmissive material to produce the printing medium A. Similarly, a printing ink is prepared and applied as a printing portion on a base material using a non-permeable material to prepare a printing medium B. Let e be the color difference ΔE between the print medium A and the print medium B in the reflected light (diffused light) under the illumination light source installed at a fixed position. Next, the color difference ΔE between the print medium A and the print medium B with transmitted light is measured under an illumination light source in which the print medium A and the print medium B are installed at fixed positions. If the measured color difference ΔE is a value different from e described above, the color difference ΔE has changed.

  Note that due to metamerism, when observed under reflected light (diffused light) under a visible light source, the color visually recognized by the naked eye was observed under reflected light (diffused light) under a specific light source. In this case, even when the first element (14) and the second element (15) are visually recognized in different colors, it is assumed that the first element (14) and the second element (15) are formed in the same color.

  FIG. 5C2 shows an example of the first latent image (4) and the second element (15) that forms the first latent image. The second element (15) is a first latent image (see FIG. 5 (c2)) that is visible by observing the substrate (7) with a light source under a visible light source. 4). The second element (15) is arranged so as to overlap within the first element (14). In the first latent image (4), a plurality of second elements (15) are arranged in the first direction (X) at the same first pitch (d1) as the first elements (14). Is formed. The first latent image (4) is obtained by changing the image line width to the maximum image line width (W3) and the minimum image line width (W4) within a predetermined range in the second element (15). It is divided into a second pattern portion (15a) and a second background portion (15b). The second pattern portion (15a) is a region for forming a character “C”, and the second background portion (15b) is a region for forming a background other than a region for forming a character “C”. . The “predetermined range” in the second element (15) is the same as the meaning of the first element (14) described above.

  FIG. 5B shows a state in which the first element (14) and the second element (15) described above are overprinted on the print medium (1). The maximum image line width (W3) of the second element (15) is equal to or smaller than the minimum image line width (W2) of the first element (14). Thereby, the 2nd element (15) can be arranged in any of the 1st pattern part (14a) and the 1st background part (14b) in the 1st element (14).

  In the first aspect of the first embodiment, the second element (15) is not cut and the second element (15) is cut out. By doing so, the second element (15) in the actual print medium (1) is transferred to the substrate (7) via the cutout area (10) where the concealing material is not printed and the second element (15). ) Can be confirmed, and as a result, the second element (15) is formed of a permeable material.

  FIG. 8 shows the configuration. As shown in FIG. 8A, a concealing layer (8) made of a concealing material is formed on a transparent substrate (7), and an image forming layer (for example, printing ink) is formed on the concealing layer (8). 9) is formed. However, the second element (15) has no color material (for example, printing ink). The second element (15) having no coloring material (for example, printing ink) and the concavity layer (8) are arranged so that the cutout area (10) to which no concealment material is applied is at the same position. Yes.

  In FIG. 8A, FIG. 8B shows a cross-sectional view at Z1-Z2. As shown in FIG. 8A, in the image forming layer (9), nothing is printed on the second element (15), and at the same time, part of the concealing layer (8) is also concealing material. This is a cutout region (10) that is not subjected to. The cutout area (10) to which no concealing material is applied has the same size and the same shape as the second element (15).

  The reason why the concealing material is printed on the transparent base material (7) is that it does not affect the visibility of the visible image (3), and thus has a role of concealing the transparency. .

(Image viewing principle in the first embodiment)
Under the reflected light (diffused light) under the visible light source, the first element (14) and the second element (15) are visually recognized in the same color, and the first latent image (4) is visually recognized by the naked eye. The first latent image (4) can be visually recognized by the naked eye under transmitted light under a visible light source. In general, the color of an object is determined by a light source, an observation environment (temperature), a spectral reflectance of the object, and the like. Although the way of visually recognizing colors varies depending on these observation conditions, in the present invention, the observation conditions are assumed to be constant conditions (for example, observation conditions: the light source is D65, the observation environment is 20 ° C., etc.).

  FIG. 9 shows a visible light source (R) when the print medium (1) according to the present invention is observed under reflected light (diffused light) and transmitted light with respect to a visible light source (R) at a fixed position. FIG. 4 is a diagram showing three positional relationships between viewpoints (E1, E2) and print medium (1). When the visible light source (R), the viewpoint (E1), and the print medium (1) are in the positional relationship shown in FIG. 9A, the observation is performed under reflected light (diffused light). When the visible light source (R), the viewpoint (E2), and the print medium (1) are in the positional relationship shown in FIG. 9B, the observation is performed under transmitted light.

  Next, the principle that the color difference ΔE between the first element (14) and the second element (15) changes to a predetermined value due to a change in the observation position will be described. As described above, the reflected light (diffused light) in the present invention is a position where the light receiving angle is −10 to 10 ° when the incident light angle from the illumination light source at a fixed position is 45 °, and the transmitted light and Is a position where the print medium (1) is placed on a straight line connecting the illumination light source at a fixed position and the viewpoint (E2), and the print medium (1) is observed with respect to the illumination light source. In the print medium (1), the first element (14) and the second element (15) are the same color in the positional relationship meaning the reflected light (diffused light) shown in FIG. In this case, the respective regions cannot be distinguished and visually recognized, and only the visible image (3) is visually recognized.

  On the other hand, in the transmitted light shown in FIG. 9B, the second element (15) is formed of a base material (7) using a transmissive material. Thereby, by changing the observation position from the reflected light (diffuse light) to the transmitted light with respect to the illumination light source at the fixed position, the brightness and / or the color is changed, and the first element (14) and the second element are changed. The color difference ΔE of the element (15) changes by a predetermined value. Therefore, the second element (15) becomes visible and the first latent image (4) becomes visible.

  FIG. 10 is a graph showing the color difference ΔE between the first element (14) and the second element (15) under reflected light (diffused light) or transmitted light according to the present invention. The left side shows the color difference ΔE between the first element (14) and the second element (15) in the reflected light (diffused light), and the right side of FIG. 10 shows the first element (14) and the first element under the transmitted light. The color difference ΔE of the second element (15) is shown. 10 is the same as that shown in FIG. 5B.

  The measurement sample is a measurement sample A (4 × 4 cm), a second element (15) having a constant width of 140 μm and a pitch of 600 μm, and a PET film having a thickness of 0.2 mm as a substrate ( 7) and on the base material (7), as the concealment layer (8), the cutout region (10) in the first concealment region (11) has the same line width and pitch as the second element (15). Using white ink (LIOJET FV03 White manufactured by Toyo Ink Manufacturing Co., Ltd.), the first hiding region (11) is solid-printed by inkjet printing, and the first element (14) is formed as an image forming layer (9). The second element (15) was printed by inkjet printing without printing.

  The measurement sample B (4 × 4 cm) has a first element (14) having a constant width of 140 μm and a pitch of 600 μm, and a PET film having a thickness of 0.2 mm as a base material (7). On the base material (7), only the first concealment region (11) (with no hollow region (10)) is used as the concealment layer (8), and white ink (LIOJET FV03 white, manufactured by Toyo Ink Manufacturing Co., Ltd.) is used. Using solid printing by inkjet printing, the first element (14) was used as the image forming layer (9) without printing the second element (15), and the process ink (LIOJET FV03 Black, manufactured by Toyo Ink Manufacturing Co., Ltd.) was used. ) Using inkjet printing.

  The graph showing the color difference ΔE between the first element (14) and the second element (15) under the reflected light (diffused light) shown in FIG. 10, and the first element (under the transmitted light shown in FIG. 14) and the color difference ΔE of the second element (15) is obtained by using a self-recording spectrophotometer (manufactured by HITACHI, model U-4000) and spectral reflectances of the measurement sample A and the measurement sample B at wavelengths of 400 to 700 nm and The spectral transmittance was measured, and the color difference ΔE was calculated from the obtained value.

  As shown in FIG. 10, under reflected light (diffuse light), the color difference ΔE between the first element (14) and the second element (15) shows a relatively small value of 1.51. ing. As described above, if the color difference ΔE is less than 6, it is visually recognized as the same color. Therefore, under the reflected light (diffused light), the first element (14) and the second element (15) are the same color. I can say that. Therefore, the first element (14) and the second element (15) are difficult to identify with the naked eye. As a result, the first latent image formed in the transmission latent image region (2). (4) cannot be visually recognized.

  Conversely, under the transmitted light shown in FIG. 10, the color difference ΔE between the first element (14) and the second element (15) is 7.12. The color difference ΔE between the first element (14) and the second element (15) under reflected light (diffuse light) is 1.51, whereas the first element (14) and the second element under transmitted light are 1.51. The color difference ΔE from the second element (15) is 7.12. That is, the color difference ΔE changes by 5.61 from 1.51 to 7.12 by changing the observation position from below reflected light (diffused light) to below transmitted light. Therefore, when the color difference ΔE changes by 5 or more, the first element (14) and the second element (15) can be identified with the naked eye, and as a result, in the transmission latent image area (2). It is possible to visually recognize the formed first latent image (4).

  Note that, under the same observation conditions, the reflected light (diffused light) and the transmitted light can be switched by changing the observation position with respect to the visible light source (R). That is, the first element (14) and the second element (15) can be identified with the naked eye by viewing the substrate (7) with respect to the visible light source (R). As a result, the first latent image (4) formed in the transmission latent image region (2) can be visually recognized.

(Visual image viewing principle)
FIG. 11 is a plan view when the transmission latent image region (2) of the printing medium (1) according to the present invention is viewed with the naked eye under reflected light (diffused light) under a visible light source (R) at a fixed position. FIG. The transmission latent image region (2) shown in FIG. 11 (a1) is, as shown in FIG. 11 (a2), the first element (14) under reflected light (diffused light) under the visible light source (R). Becomes visible with the naked eye. That is, the visible image (3) can be visually recognized. The second element (15) is visually recognized as the same color as the first element (14) under reflected light (diffused light) under a visible light source, so that it cannot be distinguished with the naked eye, The first latent image (4) formed by the second element (15) cannot be viewed with the naked eye.

  FIG. 11B is a schematic diagram when the print medium (1) is viewed with the naked eye under reflected light (diffused light) under a visible light source (R) at a fixed position. The principle of visual recognition of the visible image (3) under reflected light (diffused light) under the visible light source (R) will be described with reference to FIG. When the print medium (1) is viewed with the naked eye under reflected light (diffused light) under the visible light source (R), first, the visible light source (R) is moved toward the first element (14). The incident light (R1) generates specularly reflected light and diffused light (R2), and diffused light (R2) is obtained from the reflected light (diffused light).

  For the second element (15), the incident light (R1) from the visible light source (R) generates specularly reflected light and diffused light (R3), and the reflected light (diffused light) is diffused light (R3). ) Is obtained. Since the first element (14) and the second element (15) are formed so as to have the same color when observed under reflected light (diffused light) under a visible light source, diffusion in each region is performed. The difference in light cannot be confirmed with the naked eye.

  Under reflected light (diffused light) under a visible light source, the intensity of the diffused light in the visible image (3) and the first latent image (4) is substantially constant. Therefore, the second element (15) is arranged so as to overlap within the first element (14), and the line width of the first element (14) is made larger than that of the second element (15). Thus, the first latent image (4) is hidden in the visible image (3). Therefore, when the print medium (1) is observed under reflected light (diffused light) under a visible light source, only the visible image (3) composed of the first element (14) can be visually recognized. The first latent image (4) composed of the second element (15) cannot be visually recognized.

(First latent image image viewing principle)
12A and 12B are a plan view and a schematic view when the transmission latent image region (2) of the print medium (1) is viewed with the naked eye under transmitted light under the visible light source (R) at a fixed position. In the transmission latent image region (2) shown in FIG. 12 (a1), as shown in FIG. 12 (a2), the second element (15) is visually recognized by the naked eye under the transmitted light under the visible light source (R). It becomes possible. That is, the first latent image (4) can be visually recognized. The second element (15) can be distinguished from the first element (14) with the naked eye because the color difference ΔE is changed and viewed under transmitted light under a visible light source. The first latent image (4) formed in (15) can be viewed with the naked eye.

  The visual recognition principle of the first latent image (4) under the transmitted light under the visible light source (R) will be described with reference to FIG. When the print medium (1) is viewed with the naked eye under transmitted light under the visible light source (R), first, incident light from the visible light source (R) is applied to the first element (14). Through (R1), transmitted light (R4) is obtained. Further, in the second element (15) that forms the first latent image (4), transmitted light (R5) is obtained.

  Therefore, the second element (15) is formed of a transmissive material, and the transmitted light (R5) of the second element (15) is more than the transmitted light (R4) of the first element (14). Due to the difference in brightness, a difference in color difference ΔE occurs in the second element (15) with respect to the first element (14), and the first latent image (4) is visually recognized as a latent image. be able to. Therefore, when the print medium (1) is observed under transmitted light under a visible light source, the first latent image (4) can be newly visually recognized.

(Second aspect of the first embodiment)
Next, another embodiment of the present invention will be described. Since the base material (7) which is the first layer is the same as the first aspect of the first embodiment, it will be omitted. In addition, a part of the concealing layer (8) as the second layer and a part of the image forming layer (9) as the third layer are also omitted from the description of the first aspect of the first embodiment. And

  In the second aspect of the first embodiment, as different from the first aspect of the first embodiment, in the concealing layer (8) and the image forming layer (9), a hollow region is formed in each layer. The latent image is formed by the difference between the hidden area ratio and the transmittance without forming.

  First, the layer structure in the concealment layer (8) will be described with reference to FIG. Since the concealing layer (8) plays the role of concealing the transparency of the base material (7) as in the first aspect of the first embodiment, it is also formed using white ink. However, although white ink is printed also in the portion corresponding to the cutout region (10) in the first aspect of the first embodiment, it is formed with a hidden area ratio lower than the peripheral hidden area ratio. And this region is defined as a second concealment region (12). The first concealment region (11) is formed with the first concealment area ratio, and the second concealment region (12) is formed with the second concealment area ratio.

  Therefore, the relationship between the first hidden area ratio and the second hidden area ratio of the first hidden area (11) and the second hidden area (12) constituting the hidden layer (8) is as follows. It becomes. However, since it is necessary for the second concealment region (12) to be such that the transparency of the lower layer base material (7) can be visually recognized in the transmitted light, the second concealment area ratio is 0%. It is necessary to make the range less than 100%.

  Moreover, since it is necessary for the 1st concealment area | region (11) to suppress the transmittance | permeability of the base material (7) of a lower layer in the transmitted light, about 1st concealment area ratio is larger than 0% and 100% or less. It is necessary to be in the range. As described above, the second concealment region (12) is defined separately from the cutout region (10) in the first aspect of the first embodiment by printing white ink. The second concealed area ratio may be 0%. For example, as in the first aspect of the first embodiment, the first concealment area ratio of the first concealment region (11) is 100%, and the second concealment area of the second concealment region (12). The rate may be 0%.

  By making the second concealed area (12) have a concealed area ratio lower than that of the first concealed area (11), it is possible to visually recognize the transparency in the base material (7) under transmitted light as described above. Therefore, the first latent image (4) is formed by arranging a plurality of second concealment regions (12). Even when both the first concealment area ratio and the second concealment area ratio are set to be close to 0% or 0%, that is, even when the concealment layer (8) is substantially omitted, the printed matter is the first one. If the transmittance of the second concealment area (12) (second element (15)) is higher than that of the first concealment area (11) (first element (14)), the first latent area under transmitted light The image image (4) is visible. However, if the first hidden area ratio and the second hidden area ratio are approximated, the visibility of the first latent image (4) under transmitted light may be reduced. Therefore, the first hidden area ratio and It is necessary to appropriately set the second concealment area ratio.

  Here, the concealment area ratio is the ratio of the area where the concealment material is formed per unit area of the first concealment region (11) or the second concealment region (12) in the concealment layer (8). For example, in the second concealment region (12), the second concealment area ratio of 80% means that the ratio of the area in which the concealment material is formed in the second concealment region (12) is 80%.

  Therefore, lowering the hidden area ratio of the second hidden area ratio than the first hidden area ratio means that the ratio of hiding the base material (7) as the lower layer is lowered by lowering the hidden area ratio. A decrease in the permeability of the second concealment region (12) is suppressed as compared with the first concealment region (11). That is, when the print medium (1) is changed from the reflected light (diffused light) to the transmitted light with respect to the illumination light source at a fixed position, the image forming layer (11) corresponding to the first concealment region (11) 9) The transmitted light of the second element (15) of the image forming layer (9) corresponding to the second concealed region (12) is brighter than the transmitted light of the first element (14) of 9). This is because the visibility of the first latent image (4) under transmitted light is not lowered.

  Further, by forming a concealment material in the second concealment region (12), the brightness (intensity) of the transmitted light of the first concealment region (11) and the transmitted light of the second concealment region is approximated, The visibility of the first latent image (4) under transmitted light may be reduced. Therefore, the second concealment area ratio of the second concealment region (12) needs to be set as appropriate while paying attention to the transmitted light of the second concealment region (12).

  Next, the image forming layer (9) in the second aspect of the first embodiment will be described. About this image formation layer (9), the visible image (3) visible under the reflected light (diffused light) under a visible light source is formed like the 1st aspect of 1st Embodiment. Yes, the basic element configuration for forming a visible image is the same as the first aspect of the first embodiment.

  In the first aspect of the first embodiment, a hollow region (8) formed in the concealment layer (8) is formed in the first element (14) to form the first latent image (4). 10), the second element (15) is formed in a hollowed-out state. However, in the second aspect of the first embodiment, the first element of the first embodiment is used. The second element (15) is formed with an ink layer having a high transmittance without performing hollowing in the portion corresponding to the hollowed second element (15) in the aspect of the substrate (7) With the permeability of

  For the second element (15) in the image forming layer (9), there are two formation methods. First, as the second aspect of the first embodiment, FIG. The second will be described as a third aspect of the first embodiment described later.

  As shown in FIG. 14, the image forming layer (9) includes a first element (14) for forming a visible image (3) and a second element for forming a first latent image (4). The place including the element (15) is the same as the first aspect of the first embodiment. However, as described above, in the first element (14), the second element (15) for forming the first latent image (4) is distinguished from the first element (14). I can't.

  In FIG. 14A, in order to show the positional relationship between the first concealment region (11) and the second concealment region (12) in the lower layer, the first element (14) is illustrated by an image line. However, as shown in FIG. 14B as a cross-sectional view, there is actually no region corresponding to the second element (15) in the first element (14). However, since the area illustrated by the image line is an area for forming the first latent image (4) in the second aspect of the first embodiment, Similarly to the first aspect of the embodiment, the second element (15) is defined.

  The second element (15) is constituted entirely by the first element (14) in the first aspect of the first embodiment. However, it is necessary to set the transmittance so that the transmittance of the lowermost base material (7) can be visually recognized in the transmitted light through the second concealment region (12) in the concealment layer (8) which is the lower layer. There is. Therefore, the transmittance of the second element (15) needs to be in the range of 3% to 100%. In the present invention, setting the transmittance of the second element (15) in the range of 3% to 100% means that the spectral transmittance of the second element itself is 3% to 100% in a specific wavelength region. In other words, the state where the lowermost base material (7) cannot be confirmed at all is defined as 0%, and the state where the lowermost base material (7) is completely transmitted is defined as 100%. It means a range of 3% or more and 100% or less when used as a reference.

  The second element (15) forms the second element (15) so that the first latent image (4) cannot be viewed under reflected light (diffused light). By doing so, the substrate (7) visible through the second concealment region (12) in the concealment layer (8) under the reflected light (diffused light), and the first concealment in the concealment layer (8) It is necessary to make the colors of the region (11) be the same color. Under reflected light (diffused light), the first element (14) and the second element (15) are formed so as to have the same color.

  FIG. 15 illustrates the layer configuration in the second mode of the first embodiment. As shown in FIG. 15A, the first concealment region (11) of the concealment layer (8) formed on the substrate (7) and the image formation layer (9) of the concealment layer (9) formed further thereon. The first element (14) is arranged at the same position, the second element (15) of the imaging layer (9) is arranged in the first element (14), and likewise the second concealment area. (12) and the second element (15) are arranged at the same position. As shown in FIG. 15B, the second concealment region (12) formed in the concealment layer (8), which is the region where the first latent image (4) is actually formed, is placed on the second concealment region (12). The second element (with a transmittance of 3% or more and 100% or less) formed so that the first element (14) and the second element (15) have the same color under reflected light (diffused light). 15) is arranged.

  With the layer configuration shown in FIG. 15, as in the first aspect of the first embodiment, the first layer of the image forming layer (9) is reflected under reflected light (diffused light) under a visible light source. The visible image (3) formed by the element (14) is visible. Then, when the print medium (1) is smeared with respect to the light source, the second concealment area (12) having a concealment area ratio lower than that of the first concealment area (11) via the second element (15). ) Can further confirm the base material (7), thereby forming the second element (15), and the first latent body formed by arranging a plurality of the second elements (15). The image image (4) can be visually recognized.

(Third aspect of the first embodiment)
Next, as a third aspect of the first embodiment, apart from the first forming method in the image forming layer (9), the second forming method of the second element (15) is described. This will be described with reference to FIG. The first element (14) is the same as the image forming layer (9) (second aspect of the first embodiment) described above. However, in the second element (15), concealment of the lower layer is performed. It forms in the location applicable to the same position as the 2nd concealment area | region (12) formed in a layer (8). Therefore, the first element (14) and the second element (15) are formed of two colors. The second element (15) is formed in the range of the transmittance of 3% to 100%. If it is lower than this range, the transparency of the lowermost substrate (7) cannot be confirmed.

  As described above, the second concealment region (12) formed in the concealment layer (8) has a concealment area ratio so low that the permeability of the base material (7) can be confirmed. By forming the transmittance of the second element (15) high, the transparency of the lowermost base material (7) can be confirmed in the transmitted light through the second concealing region (12) in the lower layer. However, in the reflected light (diffused light), the first latent image (4) is invisible, so the first element (14) and the second element (15) are reflected light (diffused light). ) In the lower part, it is formed so as to be the same color.

  FIG. 17 illustrates the layer configuration of the third aspect in the first embodiment. As shown in FIGS. 17A and 17B, the first concealment region (11) of the concealment layer (8) formed on the substrate (7), and the image forming layer (9) formed thereon. ) First element (14) is arranged in the same position.

  With the layer configuration shown in FIG. 17, the image forming layer (diffused light) under the reflected light (diffused light) under the visible light source is the same as the first aspect and the second aspect in the first embodiment. The visible image (3) formed by the first element (14) of 9) is viewed. Then, when the print medium (1) is smeared with respect to the light source, the second concealment area (12) having a concealment area ratio lower than that of the first concealment area (11) via the second element (15). ), The second element (15) is formed, and the first element formed by arranging a plurality of the second elements (15). It becomes possible to visually recognize the latent image (4).

  The third aspect of the first embodiment is characterized in that a hollow region is not formed in each of the concealing layer (8) and the image forming layer (9), but the concealing layer (8) or A cutout region may be formed in either one of the image forming layers (9).

(First aspect of the second embodiment)
Next, another embodiment of the present invention will be described. The base material (7) which is the first layer is omitted because it is the same as that of the first embodiment, but in the first aspect of the second embodiment, the first layer under transmitted light is omitted. In addition to the visual effect of one latent image, the visual effect of the second latent image under an infrared light source is achieved. Therefore, the base material (7) which is the first layer is preferably formed of a transmissive material containing an infrared absorbing dye, and a specific description thereof will be described later.

  FIG. 18A is an enlarged schematic view of a part of the concealment layer (8), which is the second layer. The concealment layer (8) is the first aspect of the first embodiment. The first concealment region (11) formed of the concealment material is provided so as to correspond to the image forming layer (9) which is the third layer in the same manner as in FIG. Moreover, it has the hollow area | region (10) which does not form a concealment material, and since the concealment material is not formed in the hollow area | region (10), it is in the state which the base material (7) exposed.

  FIG. 19 is an example of a plan view and a schematic view showing a transmission latent image region according to the first aspect of the second embodiment. As shown in FIG. 19A, the print medium (1) of the present invention is similar to the first embodiment in that at least part of the transmission medium on the base material (7) made of a transparent material such as a plastic card is transmitted. A visible image (3) is formed in the latent image region (2) by printing.

  In the transmission latent image region (2) shown in FIG. 19A, a visible image (3), a first latent image (4) and a second latent image (5) which are latent images are embedded. It is. By embedding each image in the visible image (3), the visible image (3) is visually recognized under a visible light source. Under different predetermined viewing conditions, a different pattern is visually recognized for each predetermined viewing condition. It becomes possible. The transmission latent image region (2) of the present invention shown in FIG. 19A has a normal viewing condition (first viewing condition) under a visible light source and a visible light source under the configuration shown in FIG. 19B. Different visual patterns can be visually recognized according to the visual recognition condition (second visual recognition condition) that allows the base material (7) to pass through the light source and the visual observation condition (third visual recognition condition) that observation is performed under the infrared light source. it can.

  When the transmission latent image region (2) shown in FIG. 19 (a) is observed under reflected light (diffused light) under a visible light source, as shown in FIG. 19 (c1), a visible image (3) Can be visually recognized. When the transmission latent image region (2) shown in FIG. 19A is observed under transmission light under a visible light source, as shown in FIG. 19C3, the first latent image (4) is displayed. ), It is possible to visually recognize an image composed of characters, a face image, and the like. Furthermore, when observing with an appraisal device such as an infrared camera, as shown in FIG. 19 (c2), as the second latent image (5), an image composed of characters, face images, etc. is visually recognized. It becomes possible to do. As described above, the visible image (3) shown in FIG. 19A has three different patterns. The visual recognition principle will be described later.

  FIG. 19B is a schematic diagram showing a first aspect of the second embodiment. As shown in FIG. 19 (b), the visible image (3) has a first element (14) and a second element (15) on the concealment layer (8) formed on the substrate (7). And a third element (16).

  A plurality of first elements (14) are arranged at a first pitch (d1) in the first direction (X). In the 1st element (14), the 3rd element (16) is superimposed and arrange | positioned. Furthermore, the second element (15) is arranged so as to overlap in the third element (16). Accordingly, the first element (14), the second element (15), and the third element (16) are all arranged with the same first pitch (d1). The visible image (3) is formed by changing the element width or area ratio of each element within a predetermined range. In addition, the arrangement | positioning location of the 1st element (14) in the visible image (3), the 2nd element (15), and the 3rd element (16) is not limited to this, About the aspect of this form Will be described later.

Each element can be formed by a plurality of lines or dots or pixels arranged in a line as described with reference to FIG. 6 in the first embodiment. Since the details of each are the same as those in the first embodiment, description thereof is omitted here. In the following description, it is assumed that each element is formed by an image line (straight line).

  FIG. 19C1 is a diagram illustrating an example of the visible image (3) and the first element (14). A plurality of first elements (14) are arranged to form a visible image (3) that is visible under reflected light (diffused light) under a visible light source. The visible image (3) is formed by arranging a plurality of first elements (14) at the first pitch (d1) in the first direction (X). In the first element (14), the visible image (3) is obtained by partially varying the image line width as a maximum image line width (W1) and a minimum image line width (W2) within a predetermined range. Are divided into a pattern portion (14a) and a first background portion (14b). The first pattern portion (14a) is a region where the character “A” is formed in FIG. 19C1, and the first background portion (14b) is a background other than the region where the character “A” is formed. Is a region to form.

  The first element (14) is formed of a color material that does not contain an infrared absorbing dye. The first element (14) is formed of a color material that does not contain an infrared absorbing pigment, so that the visible image (3) can be viewed when observed using a special appraisal device such as an infrared camera. become unable.

  In addition, it does not specifically limit in the color material which does not contain an infrared absorption pigment | dye, if it does not have an infrared absorption characteristic, Well-known gravure ink, screen ink, process ink, etc. can be used. For example, among the basic four-color inks, cyan (C), magenta (M), and yellow (Y) have the property of not absorbing infrared rays, and if these three colors are superimposed, a black system can be expressed. The same effect as a black color material that does not absorb infrared rays can be obtained. Further, chromo fine black ink having infrared transmission characteristics (manufactured by Dainichi Seika Kogyo Co., Ltd.) and dye-based ink for inkjet printers (for example, dye-based black ink manufactured by Canon, etc.) can be used.

  In the second embodiment, the third element (16) is configured in the first element (14), and the second element (15) is further configured in the third element (16). . The first element (14), the second element (15), and the third element (16) are visually recognized in the same color under reflected light (diffused light) under a visible light source. Only (14) is visible. Thereby, under the reflected light (diffused light) under the visible light source, only the visible image (3) composed of the first element (14) is visible with the naked eye.

  In the present invention, the first element (14), the second element (15), and the third element (16) are configured with a line width that cannot be distinguished and visually recognized by the naked eye. Yes. Therefore, if the color difference ΔE is less than 6 as described above, the third element (16) cannot be visually recognized in the diffuse light reflection region under the visible light source, and the first element ( 14), the second element (15) and the third element (16) are viewed as the same color.

  FIG. 19C2 is a diagram illustrating an example of a third element (16) that forms the second latent image (5). The third element (16) is an area for forming the second latent image (5) visible in the infrared light source shown in FIG. 19 (c2). The third element (16) is arranged so as to overlap within the first element (14). The second latent image (5) has the third element (16) in the first direction (X) with the same first pitch (1) as the first element (14) and the second element (15). It is formed by arranging a plurality in d1). In the third latent image (5), in the third element (16), the image line width is partially different as a maximum image line width (W5) and a minimum image line width (W6) within a predetermined range. Thus, it is divided into a third pattern portion (16a) and a third background portion (16b). The third pattern portion (16a) is a region where the second latent image pattern (5a) having a shape of “B” in FIG. 19 (c2) is formed, and the third background portion (16b) is “B” "Is a region for forming a background other than a region for forming characters". "

  FIG. 19B shows a state in which the first element (14), the second element (15), and the third element (16) described above are overprinted on the print medium (1). is there. The maximum image line width (W5) of the third element (16) is equal to or smaller than the minimum image line width (W2) of the first element (14). Thereby, the 3rd element (16) can be arranged in any of the 1st pattern part (14a) and the 1st background part (14b) in the 1st element (14).

  The third element (16) is the same color as the first element (14) and the second element (15) under reflected light (diffused light), and is formed using a color material containing an infrared absorbing dye. . Accordingly, the third element (16) cannot be visually recognized with the naked eye under reflected light (diffused light) under a visible light source, and the first element (14) and the second element (15) And the third element (16) is viewed as the same color.

  FIG. 19 (c3) is a diagram illustrating an example of the second element (15) that forms the first latent image (4). The second element (15) is a first latent image (shown in FIG. 19 (c3)) that is visible by observing the base material (7) with respect to the light source under a visible light source. 4). The second element (15) is arranged so as to overlap with the third element (16). The first latent image (4) has the second element (15) arranged in the first direction (X) with the same first pitch (1) as the first element (14) and the third element (16). It is formed by arranging a plurality in d1). In the second latent image (4), in the second element (15), the image line width is partially different between the maximum image line width (W3) and the minimum image line width (W4) within a predetermined range. Thus, it is divided into a second pattern portion (15a) and a second background portion (15b). The second pattern portion (15a) is a region where the character “C” in FIG. 19C3 is formed, and the second background portion (15b) is a background other than the region where the character “C” is formed. Is a region to form.

  In the first latent image (4), it is possible to form only the second pattern portion (15a) without providing the second background portion (15b). However, under reflected light (diffused light), the second element (15) and the third element (16) are visually recognized as the same color by the naked eye, but the second background portion (15b) is not provided. Since the first latent image (4) is formed only by the second pattern portion (15a), the first latent image (4) and the second latent image (4) are formed in the visible image (3). There may be a difference in the size of the image (5), whereby the second element (15) and the third element (16) are identified with the naked eye even under reflected light (diffused light). Could be possible. Therefore, in order to further improve the concealment property of the second pattern portion (15a), it is preferable to provide the second background portion (15b).

  As shown in FIG. 19B, the maximum image line width (W3) of the second element (15) is equal to or smaller than the minimum image line width (W6) of the third element (16). Thereby, the 2nd element (15) can be arranged in any of the 3rd pattern part (16a) and the 3rd background part (16b) in the 3rd element (16).

  Note that the second element (15) is not printed in the third element (16), and the second element (15) is cut out in the third element (16). By doing so, the second element (15) in the actual print medium (1) is transferred to the substrate (7) via the cutout area (10) where the concealing material is not printed and the second element (15). ) Can be confirmed, and as a result, the second element (15) is formed of a permeable material.

  FIG. 20 shows the configuration. As shown in FIG. 20 (a), a concealing layer (8) made of a concealing material is formed on a transparent substrate (7), and an image forming layer (for example, printing ink) is formed on the concealing layer (8). 9) is formed. However, it is preferable to use a coloring material containing an infrared absorbing dye for the transmissive substrate (7), and a specific description thereof will be described later. As for the second element (15), neither the color material containing the infrared absorbing dye nor the color material not containing the infrared absorbing dye is disposed, and there is no color material (for example, printing ink). . The second element (15) having no coloring material (for example, printing ink) and the cutout region (10) where the concealing material is not applied in the concealing layer (8) are arranged at the same position.

  In FIG. 20A, FIG. 20B shows a cross-sectional view at Z1-Z2. As shown in FIG. 20A, in the image forming layer (9), nothing is printed on the second element (15), and at the same time, part of the concealing layer (8) is also concealing material. This is a cutout region (10) that is not subjected to. The cut-out area (10) to which no concealing material is applied has the same size and the same shape as the second element (15).

  The reason why the transparent material containing the infrared absorbing dye is used for the base material (7) is that the visibility of the second latent image (5) is not affected. In the case of using a transparent material that does not contain an infrared absorbing dye, the second element formed by partially exposing the transparent material that is the base material (7) when the print medium is observed under an infrared light source In (15), the concentration is observed to be low (whiter). On the other hand, the third element (16) formed using a color material containing an infrared absorbing dye is observed to have a high concentration (darkness). Therefore, when the second latent image (5) is observed under an infrared light source, the second element (15) affects the visibility of the second latent image (5).

  The reason why the concealing material is printed on the transparent base material (7) is that it does not affect the visibility of the visible image (3), and thus has a role of concealing the transparency. .

  Moreover, the reason for using the concealment material that does not contain the infrared absorbing dye is that it does not affect the visibility of the second latent image (5). When a concealing material containing an infrared absorbing dye is used, when the print medium is observed under an infrared light source, the first element (14), the second element (15), and the third element (16) are: All are observed to be high (dark). Therefore, the third element (16) cannot be distinguished from other elements, and as a result, the second latent image (5) that can be observed under the infrared light source cannot be viewed.

  Furthermore, the concealing layer (8) formed of the concealing material preferably has a transmittance in the infrared region lower than 80%. When the transmittance of the concealing layer (8) in the infrared region is 80% or more, the concealing layer (8) that conceals the base material (7) is transmitted when the print medium is observed under an infrared light source. The first element (14) is transmitted and the substrate (7) is observed. Therefore, when the base material (7) contains an infrared absorbing pigment, the concentration is observed to be high (blackish). Therefore, the third element (16) cannot be distinguished from other elements, and as a result, the second latent image (5) that can be observed under an infrared light source cannot be viewed. It is not preferable that the transmittance of the concealing layer (8) in the infrared region is 80% or more.

  FIG. 21 is a graph showing an example of the spectral transmittance of white ink and magenta ink according to the present invention. FIG. 21 (a) shows the spectral transmittance of the concealment material according to the present invention, using a white ink (LIOJET FV03 White manufactured by Toyo Ink Manufacturing Co., Ltd.) as a measurement sample, and colorless (transparent) infrared absorbing dye by inkjet printing. A PET film that did not contain a solid film was used. FIG. 21B is a spectral transmittance of the concealment material in the present invention. Using white ink (LIOJET FV03 White manufactured by Toyo Ink Mfg. Co., Ltd.) as a measurement sample, FIG. The sample shown in (2) was printed at a lower print density.

  FIG. 21 (c) shows the spectral transmittance of the color material that does not contain the infrared absorbing dye in the present invention, using magenta ink (LIOJET FV03 magenta manufactured by Toyo Ink Manufacturing Co., Ltd.) as a measurement sample, and PET film by inkjet printing. A solid-printed one was used. The spectral transmittance shown in FIG. 21 shows the spectral transmittance of each measurement sample divided by the spectral transmittance of a colorless (transparent) PET film as a base material. , And measured using a self-recording spectrophotometer (manufactured by HITACHI, model U-4000).

  Comparing changes in spectral transmittance in the infrared region of 760 to 800 nm, the spectral transmittance of the concealing material (a) is substantially constant at about 50% in any region. The spectral transmittance of the concealment material (b) printed at a lower print density is about 80% in the infrared region, and is therefore higher than that of the solid concealment material (a) printed. Infrared transmitting colorant (c) containing no infrared absorbing dye is about 95% in the infrared region, so it is compared with solid white ink (a) and white ink (b) printed with a reduced printing density. The value is high. At the same wavelength, in the case of a coloring material that does not contain an infrared absorbing dye, the density with the lower spectral transmittance is visually recognized as higher (whiter), and conversely, the density with the higher spectral transmittance is lower (transparent). It is visible. In addition, when observing using an infrared camera, the concealment material (a) is observed in white, the concealment material (b) printed at a reduced print density is observed as pale white, and the infrared transmission color material (C) was observed almost transparently.

  FIG. 22 is a graph showing an example of the spectral reflectance of the base material (7) according to the present invention, the hiding material for forming the hiding layer (8), the ink not containing the infrared absorbing dye, and the ink containing the infrared absorbing dye. . (A) in FIG. 22 is the spectral reflectance of the substrate (7) in the present invention, and a colorless (transparent) PET film having a thickness of 0.2 mm not containing an infrared absorbing dye was used as a measurement sample. . (B) is the spectral reflectance of the concealing layer (8) in the present invention, using a white ink (LIOJET FV03 White manufactured by Toyo Ink Manufacturing Co., Ltd.) as a measurement sample, and solidifying the PET film by inkjet printing. A printed one was used. (C) is the spectral reflectance of the coloring material that does not contain the infrared absorbing pigment in the present invention, and as a measurement sample, magenta ink (LIOJET FV03 Magenta manufactured by Toyo Ink Manufacturing Co., Ltd.) is used to form a PET film by inkjet printing. A solid-printed one was used. (D) is the spectral reflectance of the color material containing the infrared absorbing pigment in the present invention, and a black ink (LIOJET FV03 Black, manufactured by Toyo Ink Manufacturing Co., Ltd.) is used as a measurement sample, and solid on the PET film by inkjet printing. A printed one was used.

  In addition, the spectral reflectance shown in FIG. 22 was measured using a self-recording spectrophotometer (U-4000 type manufactured by HITACHI).

  Comparing changes in spectral reflectance in the visible light region of 400 to 760 nm and the infrared region of 760 to 800 nm, the spectral reflectance in the PET film (a) is substantially constant at around 95% in any region. is there. The spectral reflectance of the white ink (b) is substantially the same as that of the PET film (a) in both the visible light region and the infrared region, except for the short wavelength in the visible light region. The spectral reflectance of magenta ink (c) is substantially constant at around 95% in the infrared region. The spectral reflectance in the black ink (d) is substantially constant at around 5% in the infrared region. Note that, at the same wavelength, the density with the higher spectral reflectance is visually recognized as low (whiter), and the density with the lower spectral reflectance is visually recognized as higher (blackish). When observed using an infrared camera, the PET film (a) and the magenta ink (c) are visually recognized as whitish (substantially transparent), the white ink (b) is visually recognized as white, and the black ink (d). Was observed black.

  When observed in the infrared region using a special appraisal device such as an infrared camera, the third element (16) is visually recognized as having a high density (blackish). Similarly, since the base material (7) is a transmissive material containing an infrared absorbing dye, the second element (15) is visually recognized as having a high concentration (blackish). That is, in the infrared region, the second element (15) and the third element (16) cannot be identified. As a result, the first latent image (4) cannot be visually recognized. In the second latent image (5), an image line having a uniform density forms an image line group and is visually recognized as a formed image.

  A color material containing an infrared absorbing pigment includes black (Bk) mainly composed of carbon black. However, it is not limited to this as long as it is a colorant (especially ink) that absorbs light in the infrared region (for example, organic dyes having absorption in the infrared region such as polymethylene, phthalocyanine, azo, and anthraquinone) Compounds, and examples of the inorganic infrared absorber include antimony-doped tin oxide and tin-doped indium oxide). The first element (14), the second element (15), and the third element (16) can be formed on the print medium (1) by superimposing or tapping, but in the present invention, It is preferable to form them by superposition. When forming by tapping, high printing accuracy is required. When the printing accuracy is low, a printed portion is generated around each element. As a result, the first element (14), the second element (15), and the third element (16) do not have the same color under reflected light (diffused light) under a visible light source. Therefore, the first latent image (4) and the second latent image (5) may be visible.

  Furthermore, when observed in the infrared region, the above-mentioned printed portion transmits infrared rays. As a result, the printed part is visually recognized as having a low density, so that the second element (15) and the third element (16) in the infrared region do not become a solid region having a uniform density. One latent image (4) may be observable.

(Visual image viewing principle)
FIG. 23 is a plan view when the transmission latent image region (2) of the printing medium (1) according to the present invention is viewed with the naked eye under reflected light (diffused light) under a visible light source (R) at a fixed position. FIG. The transmission latent image region (2) shown in FIG. 23 (a1) has a first element (14) under reflected light (diffused light) under the visible light source (R) as shown in FIG. 23 (a2). Becomes visible with the naked eye. That is, the visible image (3) can be visually recognized. The first element (14), the second element (15), and the third element (16) are visually recognized in the same color under the reflected light (diffused light) under the visible light source, and are thus distinguished by the naked eye. The first latent image (4) formed by the second element (15) and the second latent image (5) formed by the third element (16) are not visible to the naked eye. It cannot be seen.

  FIG. 23B is a schematic diagram when the printing medium (1) is viewed with the naked eye under reflected light (diffused light) under a visible light source (R) at a fixed position. The visual recognition principle of the visible image (3) under reflected light (diffused light) under the visible light source (R) will be described with reference to FIG. When the print medium (1) is viewed with the naked eye in the reflected light (diffused light) under the visible light source (R), the incident light from the visible light source (R) is first applied to the first element (14). (R1) generates specularly reflected light and diffused light (R2), and diffused light (R2) is obtained under reflected light (diffused light).

  For the second element (15), the incident light (R1) from the visible light source (R) generates specularly reflected light and diffused light (R3). Under reflected light (diffused light), diffused light ( R3) is obtained. In the third element (16), the incident light (R1) from the visible light source (R) generates specularly reflected light and diffused light (R2). Under reflected light (diffused light), diffused light ( R2) is obtained. The first element (14), the second element (15), and the third element (16) are formed so as to have the same color when observed under reflected light (diffused light) under a visible light source. Therefore, the difference in diffused light in each region cannot be confirmed with the naked eye.

  In the second embodiment, the third element (16) is arranged so as to overlap in the first element (14), and the second element (15) is further superimposed in the third element (16). It is arranged. The maximum and minimum image line widths in the first element (14), the maximum and minimum image line widths in the second element (15), and the maximum and image line widths in the third element (16). The relationship between the image line widths is as follows: the minimum image line width of the first element (14) ≧ the maximum image line width of the third element (16) and the minimum image line width of the third element (16) ≧ 2nd. This is the maximum line width of the element (15).

  Under reflected light (diffused light) under a visible light source, the intensity of diffused light in the visible image (3), the first latent image (4), and the second latent image (5) is substantially constant. is there. Accordingly, the third element (16) is arranged so as to overlap within the first element (14), and the second element (15) is arranged so as to overlap within the third element (16). The first latent image (4) and the second latent image are obtained by making the line width of the element (14) larger than that of the second element (15) and the third element (16). (5) is hidden in the visible image (3). Therefore, when the print medium (1) is observed under reflected light (diffused light) under a visible light source, only the visible image (3) constituted by the first element (14) can be visually recognized. The first latent image (4) constituted by the second element (15) and the second latent image (5) constituted by the third element (16) cannot be visually recognized.

(First latent image image viewing principle)
FIG. 24 is a plan view and a schematic view when the transmission latent image region (2) of the print medium (1) is visually recognized by the naked eye under the transmitted light under the visible light source (R) at a fixed position. In the transmission latent image region (2) shown in FIG. 24 (a1), the second element (15) is visible with the naked eye under the transmitted light under the visible light source (R) shown in FIG. 24 (b). Become. That is, the first latent image (4) can be visually recognized. The second element (15) is visually distinguished from the first element (14) and the third element (16) by changing the color difference ΔE under a transmitted light under a visible light source. Thus, the first latent image (4) formed by the second element (15) can be visually recognized.

  The visual recognition principle of the first latent image (4) in the transmitted light under the visible light source (R) will be described with reference to FIG. When the print medium (1) is viewed with the naked eye in the transmitted light under the visible light source (R), the incident light from the visible light source (R) (first) is first applied to the first element (14). Transmitted light (R4) is obtained by R1). In the second element (15) that forms the first latent image (4), the transmitted light (R5) is obtained by the incident light (R1) from the visible light source (R). In the third element (16) that forms the second latent image (5), the transmitted light (R4) is obtained by the incident light (R1) from the visible light source (R).

  Therefore, the second element (15) is formed of a transmissive material, and the transmitted light (R5) of the second element (15) is transmitted through the first element (14) and the third element (16). The transmitted light (R4) of the second element (15) is higher than a certain color difference ΔE with respect to the first element (14) and the third element (16). The first latent image (4) can be visually recognized as the latent image. Therefore, under the transmitted light under the visible light source, the first latent image (4) can be visually recognized when the print medium (1) is observed.

  Note that, under the transmitted light under the visible light source, the first light depends on the difference in the intensity of the incident light (R1) from the visible light source (R), the transmittance of the base material (7), or the transmittance of the ink in each region. There may be a difference in transmitted light (R4) between the element (14) and the third element (16), and the color difference ΔE between the first element (14) and the third element (16) may change.

  However, since the second element (15) is formed using a permeable material, the amount of change in the color difference ΔE between the first element (14) and the third element (16) is the second element (15). This is smaller than the amount of change in the color difference ΔE between (15) and the third element (16). Therefore, it becomes impossible to distinguish the first element (14) and the third element (16) due to the visual masking effect. That is, the second latent image (5) cannot be visually recognized. Therefore, when the transmission latent image region (2) is viewed with the naked eye under the transmitted light under the visible light source (R), the first latent image (4) is visible.

  The visual masking effect is due to the characteristics of human visual recognition. When two large and small stimuli are given close in time and space, only large stimuli are strongly recognized and small stimuli are not recognized. It is known that a masking phenomenon (only a large stimulus can be seen) occurs, which is difficult to recognize and as a result, the small stimulus cannot be seen, and this is called a visual masking effect. Note that, depending on the setting of the element width of the second element (15) and the selection of the permeable material forming the second element (15), the first element (14) and the third element (16) The change amount of the color difference ΔE approximates the change amount of the color difference ΔE between the second element (15) and the third element (16), the visual masking effect is weakened, and the first latent image (4) is visually recognized. May decrease.

  Therefore, the change amount of the color difference ΔE between the second element (15) and the third element (16) is larger than the change amount of the color difference ΔE between the first element (14) and the third element (16). Thus, it is preferable to set the element width of the second element (15) or to appropriately select the permeable material forming the second element (15).

(The principle of visual recognition of the second latent image pattern)
FIG. 25 is a plan view and a schematic view when the transmission latent image region (2) of the print medium (1) according to the present invention is observed through an infrared display device or the like under an infrared light source (K). The principle that the second latent image (5) can be observed under the infrared light source (K) will be described with reference to FIG. When the transmission latent image region (2) of the print medium (1) is observed with an infrared display device under an infrared light source (K), the first element (14) is an infrared absorbing dye as shown in FIG. Since it is configured using a color material that does not contain, it is observed white.

  As described above, since the third element (16) is configured using the color material containing the infrared absorbing dye, the spectral reflectance is low in the infrared region, so that the concentration is high and the image is observed as black. Further, in the first aspect of the second embodiment, the second element (15) is made of a permeable material that is a base material (7) through a cutout region (10) to which no concealment material is applied. Since the substrate (7) is a transparent material containing an infrared-absorbing dye, it is set to be the same color as the third element (16) under reflected light (diffused light). Thus, when observed in the infrared region, the second element (15) and the third element (16) are observed at substantially the same concentration. Therefore, the second latent image (5) can be observed in the infrared region.

(Second aspect of the second embodiment)
Next, another embodiment of the present invention will be described. In the first aspect of the second embodiment, for the base material (7) as the first layer, a transparent material containing an infrared absorbing dye is used for the base material (7). In the second aspect, any of a transparent material containing an infrared absorbing dye and a transparent material not containing an infrared absorbing dye can be used for the substrate (7). A specific description of each case will be described later. It should be noted that a part of the concealing layer (8) that is the second layer and a part of the image forming layer (9) that is the third layer are omitted from the overlap with the first aspect of the second embodiment. I decided to.

  The second aspect of the second embodiment is different from the first aspect of the second embodiment in that the concavity layer (8) and the image forming layer (9) have a hollow region in each layer. The latent image is formed by the difference between the hidden area ratio and the transmittance without forming.

  First, the layer structure in the concealment layer (8) will be described with reference to FIG. Since the concealing layer (8) plays the role of concealing the transparency of the base material (7) as in the first aspect of the second embodiment, it is formed using white ink. However, although white ink is printed also on the portion corresponding to the cutout region (10) in the first aspect of the second embodiment, it is formed with a hidden area ratio lower than the surrounding hidden area ratio. As in the second aspect of the first embodiment, this area is defined as a second concealment area (12).

  Therefore, the relationship between the first concealment area ratio of the first concealment region (11) and the second concealment area ratio of the second concealment region (12) constituting the concealment layer (8) is as follows. Hiding area ratio> second hiding area ratio. However, since it is necessary for the second concealment region (12) to be accompanied by the transparency of the base material (7) in the lower layer in the transmitted light, the second concealment area ratio is in the range of 0% or more and less than 100%. It is necessary to.

  Moreover, since it is necessary for the 1st concealment area | region (11) to suppress the transmittance | permeability of the base material (7) of a lower layer in the transmitted light, about 1st concealment area ratio is larger than 0% and 100% or less. It is necessary to be in the range. As described above, the second concealment region (12) is defined as being separated from the cutout region (10) in the first aspect of the second embodiment by printing white ink. The second concealment area ratio of the second concealment region (12) may be 0%. For example, as in the first aspect of the second embodiment, the first hidden area ratio of the first hidden area (11) is 100%, and the second hidden area ratio of the second hidden area (12). May be 0%.

  By making the second concealed region (12) have a concealed area ratio lower than that of the first concealed region (11), as described above, the difference in transparency in the base material (7) is visually recognized in the transmitted light. Therefore, the first latent image (4) is formed by arranging a plurality of second concealment regions (12). Even if the first hidden area ratio and the second hidden area ratio are set to be approximately 0% or 0%, that is, a setting in which the hidden layer (8) is substantially omitted, the second hidden area as a printed matter. If the transparency of (12) is higher than that of the first element (14), the first latent image (4) under transmitted light is visible. However, if the first hidden area ratio and the second hidden area ratio are approximated, the visibility of the first latent image (4) in the transmitted light may be reduced. Therefore, the first hidden area ratio and the second hidden area ratio It is necessary to appropriately set the concealment area ratio of 2.

  Next, the image forming layer (9) in the second aspect of the second embodiment will be described. About this image formation layer (9), the visible image (3) visible under the reflected light (diffuse light) under a visible light source is formed like the 1st aspect of 2nd Embodiment. The basic element configuration for forming a visible image is the same as the first aspect of the second embodiment.

  In the first aspect of the second embodiment, a hollow region (8) formed in the concealment layer (8) is formed in the first element (14) in order to form the first latent image (4). The second element (15) was formed in the same position as 10) with the hollowed out state, but in the second aspect, it corresponds to the second element (15) in the first aspect. The part to be formed is not cut out, but formed with an ink layer having a high transmittance, and is accompanied by the permeability of the base material (7) which is the lowermost layer.

  For the second element (15) in the image forming layer (9), there are two formation methods. First, as the second aspect of the second embodiment, FIG. The second will be described as the third aspect of the second embodiment to be described later.

  As shown in FIG. 27, the image forming layer (9) includes a first element (14) for forming the visible image (3) and a second element for forming the first latent image (4). The third element (16) for forming the second element (15) and the third element (16) for forming the second latent image (5) is the same as the first aspect of the second embodiment. However, as described above, in the third element (16), the second element (15) for forming the first latent image (4) is distinguished from the third element (16). Can not do it.

  In FIG. 27A, in order to show the positional relationship with the first hidden area (11) and the second hidden area (13) in the lower layer, the first element (14) is illustrated by an image line. However, as shown in the cross-sectional view of FIG. 27B, there is actually no region corresponding to the second element (15) in the third element (16). However, since the area illustrated by the image line is an area for forming the first latent image (4) in the second mode of the second embodiment, The second element (15) is defined as in the first aspect of the form.

  The 2nd element (15) is comprised by the 3rd element (16) in the 1st aspect of 2nd Embodiment. However, it is necessary to set the transmittance so that the transmittance of the lowermost base material (7) can be visually recognized in the transmitted light through the second concealment region (12) in the concealment layer (8) which is the lower layer. There is. Therefore, the transmittance of the second element (15) needs to be in the range of 3% to 100%.

  The second element (15) forms the second element (15) so that the first latent image (4) cannot be viewed under reflected light (diffused light). By doing so, under the reflected light (diffused light), the first concealment region in the base material (7) and the concealment layer (8) that is visible through the second concealment region (12) in the concealment layer (8) It is necessary for the color of (11) to be the same color. Under the so-called reflected light (diffused light), the third element (16) and the second element (15) are formed so as to have the same color.

  When the lowermost base material (7) is a transparent material that does not contain an infrared absorbing dye, the second element (15) must be formed of a coloring material containing an infrared absorbing dye. When the material (7) is a transmissive material containing an infrared absorbing dye, the second element (15) is not particularly limited. This is because the visibility of the second latent image (5) is not affected. That is, it is formed of a color material containing an infrared absorbing dye when the lowermost base material (7) is observed through the second element (15), that is, the second element (15) under an infrared light source. This is so that the third element (16) is observed at the same concentration.

  FIG. 28 illustrates the layer configuration in the second mode of the second embodiment. As shown in FIG. 28 (a), the first concealment region (11) of the concealment layer (8) formed on the substrate (7) and the image formation layer (9) of the concealment layer (9) formed further thereon. The first element (14) and the third element (16) are arranged at the same position, the third element (16) is arranged in the first element (14), and the first element (14) of the image forming layer (9) is arranged. The second element (15) is arranged in the third element (16). Similarly, the second concealment area (12) and the second element (15) are arranged at the same position. As shown in FIG. 28B, the second concealment region (12) formed in the concealment layer (8), which is the region for forming the first latent image (4), is over the second concealment region (12). The second element (15) having a transmittance in the range of 3% to 100% formed so that the second element (15) and the third element (16) have the same color under reflected light (diffused light) It will be arranged.

  28, the first element of the image forming layer (9) under reflected light (diffused light) under a visible light source, as in the first aspect of the second embodiment. The visible image (3) formed by (14) is visually recognized. Then, when the print medium (1) is smeared against the light source, the second concealment area (12) having a concealment area ratio lower than that of the first concealment area (11) via the image forming layer (9). Further, the base material (7) can be confirmed. Therefore, the region in the image forming layer (9) where the substrate (7) can be confirmed through the second concealed region (12) results in the second element (15), and this second It is possible to visually recognize the first latent image (4) formed by arranging a plurality of elements (15).

(Third aspect of the second embodiment)
Next, as a third aspect of the second embodiment, apart from the first forming method in the image forming layer (9), the second forming method of the second element (15) is described. This will be described with reference to FIG. The first element (14) is the same as the image forming layer (9) of the second aspect of the second embodiment described above. However, in the second element (15), a lower concealing layer is used. It forms in the location applicable to the same position as the 2nd concealment area | region (12) formed in (8). Therefore, the second element (15) and the third element (16) are formed of two colors. The second element (15) is formed in the range of the transmittance of 3% to 100%. If it is lower than this range, the transparency of the lowermost substrate (7) cannot be confirmed.

  As described above, the second concealment region (12) formed in the concealment layer (8) has a concealment area ratio so low that the permeability of the base material (7) can be confirmed. By forming the transmittance of the second element (15) high, the transparency of the lowermost base material (7) can be confirmed in the transmitted light through the second concealing region (12) as the lower layer. . However, in order to make the first latent image (4) invisible under reflected light (diffuse light), the second element (15) and the third element (16) have the same color. To form.

  When the lowermost base material (7) is a transparent material that does not contain an infrared absorbing dye, the second element (15) must be formed of a coloring material containing an infrared absorbing dye. In the case where the material (7) is a transparent material containing an infrared absorbing dye, the second element (15) is not particularly limited.

  FIG. 30 illustrates the layer configuration of the third aspect in the second embodiment. As shown in FIGS. 30A and 30B, the first concealment region (11) of the concealment layer (8) formed on the substrate (7) and the image forming layer (11) formed thereon ( 9) the first element (14) and the third element (16) are arranged at the same position, the third element (16) is arranged in the first element (14), and the third element (14) The second element (15) is arranged in the element (16), and the second concealment region (12) and the second element (15) are arranged at the same position. As shown in FIG. 30 (b), the second concealment region (12) formed in the concealment layer (8), which is the region for forming the first latent image (4), is transmitted over the second concealment region (12). The second element (15) in the range of 3% to 100% is disposed, and the second element (15) and the third element (16) are visually recognized as the same color under reflected light (diffused light). As shown, it is formed of two colors.

  With the layer configuration shown in FIG. 30, the image forming layer (diffused light) under the reflected light (diffused light) under the visible light source is the same as the first aspect and the second aspect in the second embodiment. The visible image (3) formed by the first element (14) of 9) is viewed. Then, when the print medium (1) is smeared with respect to the light source, the second concealment region (12) having a concealment area ratio lower than that of the first concealment region (11) via the second element (15). Further, the base material (7) can be confirmed. Therefore, it is possible to visually recognize the formed first latent image (4) by arranging a plurality of the second elements (15).

  Note that the third aspect of the second embodiment is characterized in that a hollow region is not formed in each of the concealing layer (8) and the image forming layer (9), but the image forming layer (9) Any one of the second elements (15) may be formed as a hollow region.

(Modification)
FIG. 31 is a schematic diagram showing a modification of the element configuration according to the present invention. So far, each element has been described as being composed of an image line. However, as described above, each element is not limited to an image line, and a third element as shown in FIG. (16) may be an image line, and the second element (15) may be a microelement group in which a plurality of points are arranged in the same direction (T). In FIG. 31 (a), a schematic enlarged view is shown, but in actuality, the microelement group is formed by a collection of microscopic points, so that it is visually recognized as one image line. The Therefore, by using a microelement group, the microelement group is copied as one image line when copying using a printer, a copying machine, or the like. Thereby, the anti-counterfeiting effect is improved as compared with the element configuration combining only the image lines.

  Further, as shown in FIG. 31 (b), both the second element (15) and the third element (16) may be a microelement group in which a plurality of points are arranged in the same direction (T). Furthermore, as shown in FIG. 31 (c), the second element (15) is a group of minute elements in which a plurality of halftone dots are arranged in the same direction (T), and the third element (16) is A microelement group in which a plurality of pixels are arranged in the same direction (T) may be used. By using a combination of an image line or a microelement group, it becomes more difficult to duplicate, and the forgery prevention effect is improved. However, the second element (15) is arranged in the third element (16) as in the case where the second element (15) and the third element (16) described above are formed by an image line. It must be.

  In addition, when the second element (15) and / or the third element (16) is configured by a microelement group, it is necessary to arrange a plurality of points and / or pixels in the same direction. If they are arranged in different directions, periodic solid areas are generated in the visible image (3), the first latent image (4) and the second latent image (5), which is not preferable.

  The first latent image (4) and the second latent image (5) may be formed by a phase or pitch shift of the second element (15) and / or the third element (16). . As shown in FIG. 31 (d), the second element (15) forming the first latent image (4) includes a second pattern portion (15a) and a second background portion (15b). . While the second elements (15) are arranged at the first pitch (d1), the second pattern portion (15a) and the second background portion (15b) each have the second pitch (d2). It is arranged with. The second pitch (d2) is twice the first pitch (d1) of the third element (16) that forms the second latent image (5). The second element (15) of the second pattern part (15a) and the second element (15) of the second background part (15b) are arranged one by one with respect to the third element (16). Are alternately arranged.

  Further, the second pattern portion (15a) and the second background portion (15b) are configured by shifting the phase in the vertical direction with respect to the image lines of the first element (14) and the third element (16). is doing. Thus, the first latent image (4) has a relief pattern. Furthermore, as shown in FIG. 31 (e), when forming a relief pattern, the second element and the third element are not limited to the image line structure, but are composed of a group of minute elements including dots and pixels. You may do it.

(Third embodiment)
FIG. 32 is a plan view and a schematic view showing a third embodiment according to the present invention. Note that the element configuration of the image forming layer (9) will be described as being formed with an image line in the same manner as in the first and second embodiments. As shown in FIGS. 32 (a) and 32 (b), the visible image (3) has the first element (14), the second element (15), and the third element (9) as the image forming layer (9). 16). A plurality of first elements (14) are arranged at a first pitch (d1) in the first direction (X). The third element (16) has a first pitch (d1) in a second direction (Y) that is different from the first direction (X) in which the first elements (14) are arranged. Several are arranged. Since the first element (14) and the third element are arranged so that at least a part thereof is overlapped, the first element (14) and the third element are formed in a lattice pattern as shown in FIG. Furthermore, the second element (15) is arranged so as to overlap in the third element (16).

  FIG. 32 (c1) is a diagram illustrating an example of the first element (14). A plurality of first elements (14) are arranged so that a second latent image (5), which will be described later, is difficult to view under reflected light (diffused light) under a visible light source. It is formed by arranging a plurality of first elements (14) at a first pitch (d1) in the first direction (X). The plurality of first elements (14) arranged in the first element (14) have different image line widths within a predetermined range and are partially different between the maximum image line width (W1) and the minimum image line width (W2). By doing so, it is divided into a first pattern portion (14a) and a first background portion (14b). The first pattern portion (14a) is a region for forming a pattern of the shape of the letter “A” in FIG. 32C1, and the first background portion (14b) forms the background of the character “A”. It is an area to do.

  In the second embodiment described above, the pattern of the shape of the letter “A” formed in the visible image (3) under the reflected light (diffused light) under the visible light source is visible. In the embodiment, it cannot be visually recognized. The visual recognition principle will be described later.

  The first element (14) is the same color as the second element (15) and the third element (16) under reflected light (diffused light), and does not contain an infrared absorbing dye (for example, printing) Ink). The first element (14) is formed of a color material that does not include infrared absorption characteristics, so that the visible image (3) can be visually recognized when observed using a special appraisal device such as an infrared camera. become unable.

  FIG. 32 (c2) is a diagram showing an example of the second latent image (5) and the third element (16). A plurality of third elements (16) are arranged to form a second latent image (5) visible under an infrared light source. Further, the second latent image (5) is superimposed on the plurality of first elements (14) arranged as described above with different arrangement angles, so that under reflected light (diffused light) under a visible light source, A visible lattice-like visible image (3) is formed. The visual recognition principle of the visible image (3) will be described later.

  At least a part of the third element (16) is arranged so as to overlap the first element (14). The second latent image (5) is formed by arranging a plurality of third elements (16) in the second direction (Y) at the same pitch as the first pitch (d1). The second direction (Y) is a direction different from the first direction (X) and is a direction excluding the direction parallel to the first element (14). The first direction (X) and the second direction (Y) are preferably different in the vertical direction in order to make the second latent image (5) difficult to view under a visible light source. The second latent image (5) is obtained by changing the image line width to the maximum image line width (W1) and the minimum image line width (W2) within a predetermined range in the third element (16). It is divided into a third pattern part (16a) and a third background part (16b). The third pattern portion (16a) is a region for forming a pattern having a shape of a letter “A” as shown in FIG. 32 (c2), and the third background portion (16b) is a second latent image. This is the area that forms the background of the letter “A” in (5).

  The first pattern portion (14a) and the first background portion (14b) formed by the first element (14) are the third pattern portion (16a) and the third pattern portion formed by the third element (16). The configuration of the background portion (16b) and the image line width are in conflict. For example, in the first element (14), when the line width (W1) of the first pattern portion (14a) is set and the line width of the first background portion (14b) is set to (W2), The image line width (W2) in the third pattern portion (16a) is set to the same image line width as that of the first background portion (14b), and on the contrary, the image line width (W1) in the third background portion (16b) is The line width is the same as that of the first pattern portion (14a). That is, the pattern formed by the first element (14) (in fact, it cannot be visually recognized) and the second latent image (5) are configured to have a negative-positive relationship.

  The pattern of the letter “A” formed by the plurality of first elements (14) and the pattern of the letter “A” formed in the second latent image (5) And are equal in size and formed in the same region.

  Further, the third element (16) is color-matched with the first element (14) and the second element (15) under reflected light (diffused light), and uses a color material containing an infrared absorbing dye. Form. Thereby, by forming each in the same region, the density of the letter “A” by the first pattern portion (14a) and the third pattern portion (16a) in the diffuse light reflection region under the visible light source, The background density of the character “A” by the background portion (14b) of the first and the third background portion (16b) is the same as the visible image (3), and to the naked eye, the first element (14) and the second element ( 15) and the third element (16) are visually recognized as the same color, and the pattern having the shape of the letter “A” cannot be visually recognized.

  Under reflected light (diffused light) under a visible light source, all the elements of the first element (14), the second element (15), and the third element (16) are visually recognized in the same color. Further, as described above, the plurality of first elements (14) arranged in a negative / positive relationship and the third element (16) for forming the second latent image (5) are formed so as to overlap each other. In the latent image pattern region (2), the image area ratio is equal in all regions. That is, under the reflected light (diffused light) under the visible light source, the pattern of the shape of the letter “A” cannot be visually recognized, and the lattice-like visible having the same density as illustrated in FIG. Image (3) is visually recognized.

  FIG. 32 (c3) is a diagram illustrating an example of the first latent image (4) and the second element (15). A plurality of second elements (15) are arranged, so that the first latent image (4) that can be visually recognized by observing the base material (7) against the light source under a visible light source. Form. The second element (15) is arranged so as to overlap with the third element (16). The first latent image (4) is formed by arranging a plurality of second elements (15) at the same pitch as the first pitch (d1) in the second direction (Y). The first latent image (4) is obtained by changing the image line width to the maximum image line width (W3) and the minimum image line width (W4) within a predetermined range in the second element (15). It is divided into two pattern portions (15a) and a second background portion (15b). The second pattern portion (15a) is a region where the first latent image (4) having a shape of “C” is formed, and the second background portion (15b) is the first latent image (4). This is the area that forms the background.

  FIG. 32 (b) shows the third embodiment in which the first element (14), the second element (15) and the third element (16) described above are overprinted as an image forming layer (9). It shows the state. The maximum image line width (W3) of the second element (15) is set to be equal to or smaller than the minimum image line width (W2) of the third element (16). Thereby, the 2nd element (15) can be arranged in any of the 3rd pattern part (16a) and the 3rd background part (16b) in the 3rd element (16). Note that the second element (15) changes the observation angle from below reflected light (diffuse light) to below transmitted light with respect to the illumination light source at a fixed position, as in the first and second embodiments. By doing so, the color difference ΔE between the second element (15) and the third element (16) is formed using a transmissive material whose value changes by a predetermined value.

  In the third embodiment, a visible image can be visually recognized when observed under reflected light (diffused light) under a visible light source, and the first latent image is obtained by observing the print medium under transmitted light. A visible print medium could be produced. In the first embodiment, only one transmissive material forming the base material (7) or different color materials forming the second element (15) can be used for one printing. It is possible to form two images with different viewing conditions on the medium. For example, when observing under reflected light (diffused light) under a visible light source, the visible image (3) can be viewed, and the first latent image (4) can be observed by observing the printed matter under transmitted light. The first latent image appears again when the image is observed using an appraisal device such as an infrared camera. This will be described below.

  In the first aspect, the second aspect, or the third aspect of the first embodiment, the first element (14) is formed using ink that does not contain an infrared absorbing dye. Moreover, the base material (7) is made of a transparent material containing an infrared absorbing dye, or the second element (15) is formed of a color material (for example, printing ink) containing an infrared absorbing dye. As a result, the second element (15) forms a first latent image (4) that can be observed under two different observation conditions, that is, the transmitted light under a visible light source and the infrared region. This is because the first element (14) and the second element (15) are visually recognized in the same color under reflected light (diffused light) under a visible light source, making it impossible to distinguish them with the naked eye. The first latent image (4) formed by the second element (15) cannot be viewed with the naked eye.

  In addition, the second element (15) is visible with the naked eye under transmitted light under a visible light source. That is, the first latent image (4) can be visually recognized. This is because the first element (14) and the second element (15) can be distinguished with the naked eye because the color difference ΔE changes in the transmitted light under the visible light source. The first latent image (4) formed by the element (15) can be visually recognized with the naked eye. Furthermore, in the transmitted light under a visible light source, it is possible to make a combined pattern in which the first element (14) and the second element (15) are combined.

  Further, when observed through an infrared display device or the like under an infrared light source, the transparent material contains an infrared absorbing dye via the second element (15) and further via the second concealing region (12). The second element (15) formed using the base material (7) or the ink containing the infrared absorbing dye can be observed. As described above, the second element (15) is disposed within the first element (14). That is, the first latent image (4) appears again under the infrared light source.

  The visible image (3), the first latent image (4), and the second latent image (5) of the present invention are not particularly limited, such as letters, numbers, symbols, designs, or landscapes, and are appropriately selected. It is possible to design. Moreover, although the drawing line shape in the first element (14) has been described as a straight line group, if a plurality of drawing lines are arranged at the same pitch, a straight line, a wavy line, a concentric circle line, or There is no limitation, such as a wave concentric line. Furthermore, when the second element (15) and the third element (16) are made into a microelement group, a circular dot is used as a point shape, but is not limited to a circular shape. A shape such as a polygon, a random shape, or a halftone dot shape proposed in Japanese Patent No. 3478474 filed earlier by the present applicant may be used.

  As the color material for forming the first element (14), the second element (15) and the third element (16) constituting the image forming layer (9), known gravure ink, screen ink, Colored inks such as process inks and inks for inkjet printers can be used. The method for forming each element is not particularly limited, such as an offset printing method, a gravure printing method, a screen printing method, a flexographic printing method, an ink jet printer, a laser printer, or the like.

  The base material (7) used in the present invention is not particularly limited as long as at least a part thereof is made of a colorless and / or colored transmissive material, and paper such as high-quality paper, coated paper, and art paper. Leaves, films and the like can be used, and the transmittance of the permeable material is in the range of 3% to 100%.

  Moreover, the base material (7) made of a permeable material is not limited to being formed of one layer, and a layer structure as shown in FIG. 33 is possible. For example, FIG. 33A shows a single layer structure made of a colorless (transparent) transparent material (18), and FIG. 33B shows a single layer structure made of a colored transparent material (19a). 33 (c) shows a two-layer structure composed of a colorless (transparent) transparent material (18) and a colored transparent material (19a), and FIG. 33 (d) shows a colored transparent material (19a). ) And a colored transmissive material (19b), FIG. 33 (e) shows the transmissive properties of the colored transmissive material (19a), the colored transmissive material (19b) and the colorless (transparent). A three-layer structure made of the material (18) is a colorless (transparent) transparent material (18) in the lower layer. FIG. 33 (f) shows a colorless structure in the three-layer structure of FIG. 33 (e). (Transparent) transparent material (18) is disposed in the intermediate layer, and FIG. 33 (g) shows only the intermediate layer. FIG. 33 (h) shows a colored transmissive material (19a), a colored transmissive material (19b), and a colorless (transparent) transmissive material ( 18).

  Hereinafter, the present invention will be described more specifically with reference to examples, but the present invention is not limited thereto.

  As Example 1, as shown in FIG. 1, a card-type certificate (1) in which a transmission latent image region (2) according to the present invention was formed in the lower left part was produced. When this certificate (1) is observed under reflected light (diffused light) under a visible light source, the transmission latent image region (2) can be confirmed as “A” of the Gothic body shown in FIG. If the certificate (1) is confirmed against the light source under transmitted light, the transmitted latent image area (2) can be confirmed as the Gothic “C” shown in FIG. 2 (b). it can.

  The base material (7) of the certificate (1) in Example 1 was a colorless (transparent) PET film having a thickness of 0.2 mm. Therefore, in Example 1, the permeable material was used on the entire surface of the base material, that is, the base material itself.

  Next, except for the transmission latent image region (2) on the base material (7), solid printing was performed using white ink (LIOJET FV03 white manufactured by Toyo Ink Manufacturing Co., Ltd.), and the transmission latent image region (2) was the same. Using the white ink, the first concealed area (11) for suppressing the permeability of the PET film of the base material (7) and the area where the white ink is not printed ("cutout area (10)" in the above-described embodiment) ) To form a concealing layer (8).

  The first concealment region (11) was printed with a concealment area ratio of 100% (solid). Further, the cutout region (10) where the white ink is not printed is at the same position as the second element (15) of the image forming layer (9) printed on the white ink.

  Next, an image forming layer (9) was formed on the entire surface of the concealing layer (8) formed with white ink using process ink (LIOJET FV03 cyan, magenta, yellow and black, manufactured by Toyo Ink Manufacturing Co., Ltd.). . For this image forming layer (9), normal printing is performed with halftone dots other than the transmission latent image region (2), and the transmission latent image region (2) is the first embodiment as shown in FIG. The pattern shown in FIG. 5A was formed by the first element configuration in the form.

  Each element in the transmission latent image region (2) of the image forming layer (9) was a straight line-shaped image line having a pitch of 600 μm and equally spaced. The first element (14) had a maximum image line width (W1) of 180 μm and a minimum image line width (W2) of 110 μm. The second element (15) had a maximum image line width (W3) of 110 μm and a minimum image line width (W4) of 30 μm.

  The image forming layer (9) was formed according to the third aspect of the first embodiment shown in FIG. The first element (14) was printed in black by superimposing process inks (LIOJET FV03 cyan, magenta and yellow, manufactured by Toyo Ink Manufacturing Co., Ltd.). In accordance with the gradation of “A” of the Gothic body shown in FIG. 2A, the image line width of the first element (14) is a maximum image line width (W1) of 180 μm and a minimum image line width (W2) of 110 μm. A visible image (3) was formed by changing within the range.

  Next, as described above, the second element (15) is located at the same position as the cutout area (10) where the white ink of the concealing layer (8) is not printed. Accordingly, the second element (15) of the image forming layer (9) and the cutout area (10) of the concealing layer (8) are in the same position, so that the area has the second element (15). In this state, the PET film of the substrate (7) can be confirmed.

  In order not to make the first latent image (4) formed by the second element (15) visible under reflected light (diffused light), the second element (15) is reflected light (diffused light). Below, it printed using process ink (LIOJET FV03 black by Toyo Ink Manufacturing Co., Ltd.) so that it might become the same color as the 1st element (14). In accordance with the gradation of “C” of the Gothic body shown in FIG. 2B, the image line width of the second element (15) is 110 μm for the maximum image line width (W3) and 30 μm for the minimum image line width (W4). The first latent image (4) was formed by changing within the range. The color difference ΔE between the first element (14) and the second element (15) under reflected light (diffused light) was 1.20.

  FIG. 34 schematically shows the configuration of the transmission latent image region (2) in the certificate (1) of Example 1 and the configuration of regions other than the transmission latent image region (2). FIG. 34 (a) shows a configuration of a region other than the transmission latent image region (2), and a white ink is printed on a colorless (transparent) PET film that is a transparent substrate (7). Furthermore, a halftone dot for forming a visible image (3) is printed with the process ink.

  FIG. 34 (b) shows the configuration of the transmission latent image region (2), and FIG. 34 (c) shows a cross-sectional view at Z1-Z2. As shown in FIG. 34 (b), on the colorless (transparent) PET film which is the transparent base material (7), the first concealment region (11) is formed of white ink as the concealment layer (8). Printed, part of which is a cutout area (10) where no concealing material is applied. A first element (14) is printed on the first concealment area (11) and a second element (15) is printed on the cutout area (10), in particular this cutout area. (10) and the second element (15) are printed at the same position.

  In addition, if it supplements about the 2nd element (15) formed on the hollow area | region (10) in the concealment layer (8), in FIG.34 (c), the 2nd element (15) on the hollow area | region (10) will be shown. The area corresponding to the cut-out region (10) is formed in a state like a cavity, but this is only a schematic representation, and there is a cavity in the actual print medium (1). I do not mean. As a layer structure of the printing medium, it means that a concealing layer (8) having a cutout region (10) is formed on a substrate (7) and an image forming layer (9) is formed thereon, This means that the second element (15) constituting the image forming layer (9) is printed at the same position as the cutout region (10) where the hiding layer (8) does not exist.

  By adopting such a positional relationship between the layer configuration and the element configuration, it is possible to confirm the permeability of the base material (7) through the cutout region (10) in the second element (15) as described above. It becomes. Further, since the transparency of the base material (7) is suppressed by the white ink in the areas other than the cut-out area (10), it is visible by the process ink printed on the white ink without any transparency. An image (3) is formed.

  When the print medium (1) produced in Example 1 was observed with the naked eye under reflected light (diffused light) under a visible light source whose illumination light source was at a fixed position, the letter “A”, which is a visible image (3) And the first latent image (4) could not be visually recognized. Next, when the printing medium (1) produced in Example 1 was observed with the naked eye under transmitted light under a visible light source whose illumination light source was at a fixed position, the second element (15) was visually recognized brightly, One latent image (4) was visible.

  When viewed with the naked eye under transmitted light under a visible light source, the transmitted light (R5) of the second element (15) forming the first latent image (4) is transmitted by the first element (14). Since the color difference ΔE between the second element (15) and the first element (14) is greatly changed due to the difference in brightness, the first latent image (4) is visually recognized. It became possible.

  Furthermore, the print medium (1) produced in Example 1 was equipped with a sharp cut filter IR-80 manufactured by Fuji Photo Film Co., Ltd. on an infrared display device (Cortex camera WAT-704R manufactured by Watec Co., Ltd.) under an infrared light source. Observed). Visible image (3) could not be observed. Further, the first latent image (4) composed of the second element (15) is displayed dark (blackish), and the first latent image (4) can be clearly seen again. .

  As Example 2, as shown in FIG. 35, a card type certificate (1 ') having a transmission latent image region (2') according to the present invention formed in the lower right portion was produced. When this certificate (1 ′) is observed under reflected light (diffused light) under a visible light source, the transmission latent image area (2 ′) confirms the figure of “star” shown in FIG. When the certificate (1 ′) is passed through the light source and confirmed under transmitted light, the transmitted latent image area (2 ′) is a Gothic “OK” as shown in FIG. The characters can be visually recognized, and when viewed through an infrared display device or the like under an infrared light source (K), the Gothic “pass” characters shown in FIG. 36B may be confirmed. it can.

  As the base material (7 ') of the certificate (1') in Example 2, a colorless (transparent) PET film having a thickness of 0.2 mm was used. Therefore, in Example 2, the permeable material was used on the entire surface of the base material, that is, the base material itself.

  Next, a solid image is printed on the substrate (7 ′) other than the transmission latent image region (2 ′) using white ink (LIOJET FV03 White manufactured by Toyo Ink Manufacturing Co., Ltd.), and the transmission latent image region (2 ′) is printed. The same white ink is used so that the transparency of the first concealment region (11 ′) and the base material (7 ′) for suppressing the transparency of the PET film of the base material (7 ′) is visible. The concealment layer (8 ′) was formed so as to have the second concealment region (12 ′) having a concealment area ratio.

  The first hidden area (11 ′) was printed with a first hidden area ratio of 100% (solid), and the second hidden area (12 ′) was printed with a second hidden area ratio of 10%. . The second concealment region (12 ') is located at the same position (corresponding to) the second element (15') of the image forming layer (9 ') printed on the white ink.

  Next, an image forming layer (9 ′) is formed on the entire surface of the concealment layer (8 ′) formed with white ink using process ink (LIOJET FV03 cyan, magenta, yellow and black manufactured by Toyo Ink Manufacturing Co., Ltd.). Formed. For this image forming layer (9 ′), normal printing is performed with halftone dots except for the transmission latent image region (2 ′), and the transmission latent image region (2 ′) is the second one as shown in FIG. The pattern of FIG. 36A was formed by the second element configuration in the second embodiment.

  Each element in the transmission latent image region (2 ') of the image forming layer (9') was a straight line-shaped image line having a pitch of 600 μm and an equal interval. The first element (14 ') had a maximum image line width (W1) of 300 μm and a minimum image line width (W2) of 180 μm. The third element (16 ') had a maximum image line width (W5) of 180 μm and a minimum image line width (W6) of 110 μm. The second element (15 ') had a maximum image line width (W3) of 110 μm and a minimum image line width (W4) of 30 μm.

  The image forming layer (9 ') was formed according to the third aspect of the second embodiment shown in FIG. The first element (14 ') was printed in black by superimposing process inks (LIOJET FV03 cyan, magenta and yellow, manufactured by Toyo Ink Manufacturing Co., Ltd.). In accordance with the gradation of the “star” figure shown in FIG. 36A, the image line width of the first element (14 ′) is 300 μm for the maximum image line width (W1) and 180 μm for the minimum image line width (W2). A visible image (3 ′) was formed by changing within the range.

  Next, a third element (16 ') was formed in the first element (14'). In order to prevent the second latent image (5 ′) formed by the third element (16 ′) from being viewed under reflected light (diffused light), the third element (16 ′) Under diffuse light, printing was performed using process ink (LIOJET FV03 Black, manufactured by Toyo Ink Manufacturing Co., Ltd.) so as to be the same color as the first element (14 ′). The image line width of the third element (16 ′) is set to a maximum image line width (W5) of 180 μm and a minimum image line width (W6) of 110 μm in accordance with the Gothic “pass” gradation shown in FIG. And a second latent image (5 ′) was formed. The color difference ΔE between the first element (14 ′) and the third element (16 ′) under reflected light (diffused light) was 1.05.

  Next, as described above, the second element (15 ') was formed at the same position as the second concealment region (12') of the concealment layer (8 '). Accordingly, since the second element (15 ′) of the image forming layer (9 ′) and the second concealment region (12 ′) of the concealment layer (8 ′) are at the same position, the region is The PET film of the base material (7 ′) can be confirmed through the second element (15 ′) and further through the second concealed region (12 ′) of the lower layer.

  In order to prevent the first latent image (4 ′) formed by the second element (15 ′) from being viewed under reflected light (diffused light), the second element (15 ′) It was printed using process ink (LIOJET FV03 Black, manufactured by Toyo Ink Manufacturing Co., Ltd.) so as to be the same color as the third element (16 ′) under diffuse light). In accordance with the gradation of “OK” of the Gothic type shown in FIG. 36C, the image line width of the second element (15 ′) is set to the maximum image line width (W3) of 110 μm and the minimum image line width (W4) of 30 μm. The first latent image (4 ′) was formed by changing within the range. The color difference ΔE between the second element (15 ′) and the third element (16 ′) under reflected light (diffused light) was 0.88.

  FIG. 37 schematically shows the configuration of the transmission latent image region (2 ′) in the certificate (1 ′) of Example 2 and the configuration in the region other than the transmission latent image region (2 ′). FIG. 37 (a) shows a halftone dot configuration in a region other than the transmission latent image region (2 ′), and a white ink is formed on a colorless (transparent) PET film that is a transparent substrate (7 ′). Is printed, and further, a halftone dot for forming a visible image (3) is printed on it with process ink.

  FIG. 37B shows the configuration of the transmission latent image region (2 ′), and FIG. 37C shows a cross-sectional view taken along Z1-Z2. As shown in FIG. 37 (b), on the colorless (transparent) PET film which is the transparent base material (7 ′), the first concealment region (11 ′) and the second concealment region (12 ′ ) Is printed with white ink, the first element (14 ') is printed on the first concealed area (11'), and the third element (16 ') is printed in the first element (14'). ') Was printed, and the second element (15') was printed on the second concealment region (12 '). In particular, the second concealment region (12 ') and the second element (15') are printed at the same position.

  By adopting such a positional relationship between the layer configuration and the element configuration, as described above, in the second element (15 ′), the permeability of the base material (7 ′) through the second concealment region (12 ′). Can be confirmed. In addition, the area other than the second concealment area (12 ') is printed on the white ink in a non-transparent state because the transparency of the base material (7) is suppressed by solid printing of the white ink. A visible image (3 ′) is formed by the processed process ink.

  When the print medium (1 ′) produced in Example 2 was observed with the naked eye under reflected light (diffused light) under a visible light source whose illumination light source was at a fixed position, the “star” shown in FIG. The visible image (3 ′) of the figure could be visually recognized, and the first latent image (4 ′) and the second latent image (5 ′) could not be visually recognized. Next, when the print medium (1 ′) produced in Example 2 was observed with the naked eye under transmitted light under a visible light source whose illumination light source was in a fixed position, the second element (15 ′) was brightly visible. Thus, the first latent image (4 ′) of the characters “OK” shown in FIG.

  When viewed with the naked eye under transmitted light under a visible light source, the transmitted light (R5) of the second element (15 ′) forming the first latent image (4 ′) is the first element (14 ′). ) And the transmitted light (R4) of the third element (16 ′), and the color difference ΔE between the second element (15 ′) and the third element (16 ′) greatly changes due to the difference in brightness. Therefore, the first latent image (4 ′) can be visually recognized.

  Furthermore, the print medium (1 ') produced in Example 2 was mounted with a sharp cut filter IR-80 manufactured by Fuji Photo Film Co., Ltd. on an infrared display device (Corporate Camera WAT-704R manufactured by Watec Co., Ltd.) under an infrared light source. Observed). The visible image (3 ') could not be observed. The second element (15 ') was displayed dark (blackish), and the third element (16') was also displayed dark (blackish). Therefore, the second latent image (5 ′) formed of the third element (16 ′) and having the character “PASS” in the Gothic type as shown in FIG. 36B can be visually recognized. It was. The second element (15 ′) is the same color as the third element (16 ′) under reflected light (diffused light) under a visible light source, and uses a color material containing an infrared absorbing dye. Therefore, since the second element (15 ′) and the third element (16 ′) cannot be identified in the infrared region, the first element formed in the second latent image (5 ′) The latent image (4 ′) could not be visually recognized. As a result, only the second latent image pattern (5 ') could be observed.

1, 1 'print medium having a transmission latent image 2, 2' transmission latent image region 3, 3 'visible image 4, 4' first latent image 5, 5 'second latent image 6, 6' Transparent material 7, 7 'Substrate 8, 8' Hiding layer 9, 9 'Image forming layer 10, 10' Hollow area 11, 11 'First hiding area 12, 12' Second hiding area 14, 14 ' 1st element 14a 1st pattern part 14b 1st background part 15, 15 '2nd element 15a 2nd pattern part 15b 2nd background part 16, 16' 3rd element 16a 3rd pattern part 16b Third background 18 Colorless transparent material 19a, 19b Colored transparent material R Visible light source K Infrared light source d1 First pitch d2 Second pitch L1 Predetermined range X First direction Y Second direction

Claims (10)

In a substrate made of at least a part of a colorless and / or colored transparent material, a transmission latent image region is formed on a part of the substrate made of the transparent material,
In the transmission latent image region on the substrate, a concealing layer made of a concealing material for suppressing the transparency of the transmissive material is formed,
i) The concealment layer includes a first concealment area composed of a first concealment area ratio provided with a concealment material that conceals the permeability of the base material, and the concealment material for partially exposing the base material. Ii) the concealing layer comprises a first concealment area comprising a first concealment area ratio provided with a concealment material concealing the permeability of the substrate, and the first concealment region. Formed by a second concealment region comprising a second concealment area ratio lower than the concealment area ratio of
Furthermore, an image forming layer is formed on the concealment layer by arranging a plurality of first elements and second elements in a line.
The plurality of first elements are divided into a first pattern portion and a first background portion by forming a visible image by partially varying the element width depending on a colored color material,
In the case of i), a second element not formed with the colored coloring material is formed in the first element, and the second pattern portion is formed by partially varying the element width in the second element. And the second background portion, the cut-out area and the second element are arranged at the same location, and a first latent image is formed by arranging a plurality of the second elements,
In the case of ii), a second element having a transmittance of 3% or more and 100% or less is formed in the first element by the colored color material, and the element width is partially different in the second element. In this way, the second pattern portion and the second background portion are divided, the second concealment region and the second element are arranged at the same location, and a plurality of the second elements are arranged to form the first A latent image is formed,
By forming the first element and the second element so as to have the same color in the diffused light region, the visible image is visually recognized in the diffused light region under the visible light source, and the base material is transmitted under the transmitted light. A printing medium having a transmission latent image, wherein the first latent image can be visually recognized when observed with a lens. In the case of i), the cutout area and the second element have the same shape and size, or
2. The print medium having a transmission latent image according to claim 1, wherein in the case of ii), the second concealment area and the second element have the same shape and size. The print medium having a transmission latent image according to claim 1, wherein the first element and the second element are arranged at an equal first pitch. 4. The transmission latent according to claim 1, wherein the first element and the second element are made of at least one of an image line or a group of microelements, or a combination thereof. 5. A print medium having an image. A transmission latent image region is formed on a substrate that is at least partially made of a colorless and / or colored transparent material and includes an infrared absorbing dye or no infrared absorbing dye;
In the transmission latent image region, a concealing layer made of a concealing material that does not contain an infrared absorbing dye and suppresses the transmittance of the transmissive material is formed,
iii) The concealing layer includes a first concealing area composed of a first concealing area ratio provided with a concealing material concealing the permeability of the base material, and the concealing material for partially exposing the base material. Or iv) the concealing layer includes a first concealment area composed of a first concealment area ratio provided with a concealment material concealing the permeability of the substrate, and the first concealment region Formed by a second concealment region comprising a second concealment area ratio lower than the concealment area ratio of
Furthermore, on the concealment layer, a plurality of first elements, second elements and third elements are arranged in a line to form an image forming layer,
The plurality of first elements are divided into a first pattern part and a first background part by making the element width partly different by a colored color material not containing an infrared absorbing dye,
v) The third element is arranged so as to overlap within the first element by the colored coloring material containing an infrared absorbing dye, or
vi) The third element is partially overlapped with the first element and arranged in a direction different from the first element by the colored coloring material containing an infrared absorbing dye,
In the third element, the second latent image is formed by dividing the element width partially into a third pattern portion and a third background portion,
In the case of iii), the base material contains an infrared-absorbing dye, a second element that is not provided with a colored coloring material is formed in the third element, and a part of the element width of the second element is formed. It is divided into a second pattern portion and a second background portion by making them different, and the cutout region and the second element are arranged at the same location, and a plurality of the second elements are arranged to form the first A latent image is formed,
In the case of iv), the second element is disposed in the third element so as to overlap with the second concealment region, and when the substrate contains an infrared absorbing dye, the transmittance is 3% or more and 100% or less, and formed of a colored material containing or not containing an infrared absorbing dye, or when the substrate does not contain an infrared absorbing dye, the transmittance is 3% or more and 100% or less, and infrared rays Formed by the colored color material containing an absorbing dye, and the first latent image is formed by dividing the element width into a second pattern portion and a second background portion,
In the case of v), a visible image composed of the first pattern portion and the first background portion is formed, or
In the case of vi), visible images having the same density of the first pattern portion and the third background portion and the first background portion and the third pattern portion are formed,
By forming the first element, the second element, and the third element so as to have the same color in the diffused light region, the visible image is visually recognized in the diffused light region under the visible light source, and the base The second latent image is visible when the material is observed under infrared light, and the first latent image is visible when the substrate is observed under transmitted light. A print medium having an image. In the case of iii), the cutout area and the second element have the same shape and size, or
6. The print medium having a transmission latent image according to claim 5, wherein in the case of iv), the second concealment area and the second element have the same shape and size. In the case of vi), the element width of the first element forming the first pattern portion and the element width of the third element forming the third background portion are: And the element width of the first element forming the first background portion is equal to the element width of the third element forming the third pattern portion, A printing medium having a transmission latent image according to claim 5. In the case of vi), the pattern formed by the first element and the third pattern portion have the same shape and size, and are formed at the same position. 8. A print medium having the transmission latent image image according to 7. The transmission latent according to claim 5, wherein the first element, the second element, and the third element are all arranged at an equal first pitch. A print medium having an image. The said 1st element, the said 2nd element, and the said 3rd element consist of at least one of a drawing line or a microelement group, or each combination, The any one of Claims 5 thru | or 9 characterized by the above-mentioned. A print medium having the transmission latent image image according to the item.

Images