Latent image print

Abstract

The present invention provides a latent image print that can improve the visibility of the visible image while ensuring the accuracy of reading the latent image. [Solution] The latent image printed material according to the present invention comprises a first printed pattern formed in at least a portion of the printing area of ​​a substrate. The first printed pattern consists of lines with partially different angles, and the latent image is made visible by a reading device that reads the difference in angles of the lines. In addition, a printed element of a figure consisting of line segments and curves or a combination thereof, with angles different from those of the lines, is placed adjacent to at least one end of the plurality of lines constituting the first printed pattern.

Description

Technical Field

[0001] The present invention relates to a latent image printed matter that can be output by a printing machine in the field of valuable printed matters such as banknotes, passports, securities, identity certificates, cards, tickets, etc. that require anti-counterfeiting effects.

Background Art

[0002] In valuable printed matters such as banknotes, passports, securities, certificates, important documents, etc., it is important to prevent forgery and alteration. As one of these anti-counterfeiting measures, there is a latent image printed matter in which characters, figures, etc. are made latent so that they cannot be recognized visually by complicating the arrangement of halftone dots or ruled lines or forming a printed pattern with a special material or the like.

[0003] In such a latent image printed matter, there is known a latent image printed matter in which ruled lines having the same shape, size, and color are provided in the latent image portion and the background portion, and the arranged angles are different (see, for example, Patent Document 1). The latent image printed matters disclosed in Patent Document 1 and Patent Document 2 can be visualized by a reading device that extracts edges.

[0004] In the latent image printed matter disclosed in Patent Document 1, a third ruled line is arranged at a position that does not overlap with the first ruled line and the second ruled line having different angles from each other. Note that Patent Document 1 discloses that a visible image is formed by arranging halftone dots by an FM screen at a position that does not overlap with the first ruled line and the second ruled line.

[0005] Also, Patent Document 2 also discloses a latent image printed matter in which three types of ruled lines are arranged. In the technique disclosed in Patent Document 2, when visualizing a latent image from a latent image printed matter in which first ruled lines and second ruled lines having different angles are formed according to color components of a color image, the first ruled line and the second ruled line are colored with different colors, so that a color latent image can be visually recognized.

Prior Art Documents

Patent Documents

[0006] [Patent Document 1] Patent No. 6976527 [Patent Document 2] Patent No. 7323112 [Overview of the Initiative] [Problems that the invention aims to solve]

[0007] However, in the latent image print disclosed in Patent Document 1, when halftone dots were placed in positions that did not overlap with the first and second lines to form a visible image, the halftone dots constituting the visible image were sometimes edge-extracted, which reduced the accuracy of reading the latent image. In such cases, in order to avoid affecting the reading of the latent image, it was necessary to make the visible image a faint image, which sometimes resulted in insufficient visibility of the visible image.

[0008] Therefore, the present invention aims to provide a latent image print that can improve the visibility of the visible image while ensuring the accuracy of reading the latent image. [Means for solving the problem]

[0009] The latent image printed material according to the present invention comprises a first printed pattern that is visible as a uniform density, comprising a plurality of lines of a different color from the substrate arranged in a printing area of ​​at least a part of the substrate, wherein the lines arranged in the printing area have partially different angles, and the latent image is made visible by a reading device that reads the difference in angles of the lines, wherein a second printed pattern is formed by placing a graphic printing element consisting of line segments and curves or a combination thereof, in a direction different from the angle of the lines, adjacent to at least one end of the plurality of lines constituting the first printed pattern.

[0010] Furthermore, the latent image print according to the present invention is characterized in that printed elements are placed adjacent to the ends of all the lines constituting the first printed pattern, and the printed elements are partially different in color and size.

[0011] Furthermore, the latent image print according to the present invention is characterized in that a part of one printing element has a first halftone dot formed with an ink having infrared absorption properties, and a printing element different from the one printing element has a second halftone dot formed with an ink having infrared transmission properties and is visible as the same color as the first halftone dot. [Effects of the Invention]

[0012] According to the latent image print of the present invention, the printing elements constituting the second print pattern, which is visible as a visible image, are arranged adjacent to the ends of the lines constituting the first print pattern, and the printing elements are made up of line segments and curves or combinations thereof, which are in a direction different from the angle of the lines constituting the first print pattern. This makes it possible to improve the contrast of the visible image without affecting the accuracy of reading the latent image visualized from the first print pattern. [Brief explanation of the drawing]

[0013] [Figure 1] This is a plan view of a latent image print according to the first embodiment. [Figure 2] This diagram shows the structure of the printed pattern formed on a latent image print. [Figure 3] This is a diagram illustrating the composition of a printed pattern in detail. [Figure 4] This is a schematic diagram illustrating a method for visualizing a latent image from a first printed pattern. [Figure 5] This figure shows examples of printing elements that make up the second printed pattern. [Figure 6] This is a plan view of a latent image print according to the second embodiment. [Figure 7] This figure shows an example of printing elements that constitute the second printed pattern of the second embodiment. [Figure 8] This figure shows another example of a printing element that constitutes the second printed pattern of the second embodiment. [Figure 9] This figure shows another example of a printing element that constitutes the second printed pattern of the second embodiment. [Figure 10]It is a diagram for enlarging and explaining a partial area of a printed pattern according to the third embodiment. [Figure 11] It is a diagram for enlarging and explaining another partial area of a printed pattern according to the third embodiment.

Mode for Carrying Out the Invention

[0014] Embodiments of the present invention will be described with reference to the drawings. However, the present invention is not limited to the best mode for implementation described below, and various other modes can be implemented as long as they are within the scope of the technical idea described in the claims.

[0015] (First Embodiment) FIG. 1 is a plan view of a latent image printed matter (1) according to the first embodiment. The latent image printed matter (1) shown in FIG. 1 includes a printed pattern (20) formed in a printing area (11) of a base material (10). For the base material (10), as long as the printed pattern (20) can be formed, paper, film, a composite base material obtained by coating paper with film, or the like can be used.

[0016] FIG. 2 is a diagram showing the configuration of the printed pattern (20) according to the first embodiment. The printed pattern (20) shown in FIG. 2 is composed of a first printed pattern (21) in which a latent image is visualized by a reading device (100) described later, and a second printed pattern (22) that forms a visible image. In the present invention, the designs of the latent image and the visible image may be numbers, symbols, logos, etc., and are not particularly limited. However, in the present embodiment, an example in which the latent image is composed of the letter "A" and the visible image is composed of the letter "C" will be described.

[0017] (The First Printed Pattern) The structure of the first printed pattern (21) will be explained using Figure 3. As shown in the enlarged view of Figure 3, the first printed pattern (21) has a plurality of units (210) divided into a grid, and each unit (210) has one first line (211) or one second line (212). In the enlarged view of Figure 3, the areas of the units (210) are shown with solid lines to make it easier to understand where the first line (211) or the second line (212) is placed, but these are not actually printed on the latent image print (1). The first line (211) and the second line (212) are formed from a material having a different color from the color of the substrate (10), such as ink. The material used to form the first stroke (211) and the second stroke (212) is not particularly limited as long as it is a different color from the base material (10). Common materials such as CMYK inks or special color inks such as green, brown, and purple can be used.

[0018] In the first printed pattern (21) shown in Figure 3, the first stroke (211) and the second stroke (212) are composed of straight lines with equal width and length, and the area ratio of the first stroke (211) and the second stroke (212) is equal in each unit (210). Here, the area ratio is the ratio of the area of ​​the first stroke (211) or the second stroke (212) to the area of ​​a unit (210) having a fixed area within the printed area (11). Due to the configuration in which the area ratios of the first stroke (211) and the second stroke (212) are equal in each unit (210), the area ratios of the first stroke (211) and the second stroke (212) distributed throughout the entire printed area (11) are equal, and the printed pattern (20) is perceived as having a uniform density.

[0019] If the vertical and horizontal dimensions of a unit (210) are small, the lines formed within the unit (210) will not be recognized by near vision and will be observed as a uniform density. However, if each unit (210) is large, the lines formed within the unit (210) will be observed as lines. The latent image printed material (1) of the present invention is intended to form a highly concealable latent image, and it is preferable that the lines formed within the unit (210) are not recognized as lines by near vision. For this reason, the vertical and horizontal dimensions of the unit (210) are preferably in the range of 0.18 mm to 0.50 mm.

[0020] In the first printed pattern (21) shown in Figure 3, the first line (211) and the second line (212) are shown as straight lines of equal length. However, in the present invention, the shapes of the first line (211) and the second line (212) may be not only straight lines, but also dotted or dashed lines, as long as the reading device that extracts edges can distinguish and extract the first line (211) and the second line (212). In the following description, an example in which the first line (211) and the second line (212) are formed as straight lines will be described.

[0021] In the present invention, the first stroke (211) and the second stroke (212) have different angles of inclination with respect to the horizontal direction, corresponding to the pattern of the latent image visualized by the edge-extracting reader. The first printed pattern (21) shown in Figure 3 is an example in which the pattern of the latent image visualized by the reader is the letter "A", the first stroke (211) is placed in the area of ​​the letter "A" and is inclined at 45 degrees with respect to the horizontal direction, and the second stroke (212) is placed in the area surrounding the letter "A" and is inclined at 135 degrees with respect to the horizontal direction. In other words, it shows an example in which the angle between the first stroke (211) and the second stroke (212) differs by 90 degrees. As mentioned above, if the first stroke (211) and the second stroke (212) can be distinguished by the edge-extracting reader, the angle between the first stroke (211) and the second stroke (212) is not limited to 90 degrees.

[0022] (Second printing pattern) As shown in Figure 3, the second printed pattern (22) is composed of printed elements (221) positioned to form the letter "C" in the visible image, adjacent to the ends of the first stroke (211) and the second stroke (212). Note that, as shown in the enlarged view of Figure 3, the printed elements (221) do not need to be placed in all the spaces between the ends of the first stroke (211) and the ends of the second stroke (212), between the ends of the first stroke (211) themselves, and between the ends of the second stroke (212) themselves. Depending on the shape of the second printed pattern (22), they only need to be placed in at least one of the ends of the first stroke (211) and the second stroke (212).

[0023] The color of the print element (221) may be the same as the color of the first stroke (211) and the second stroke (212), or it may be a different color. Furthermore, the material used to form the print element (221) can be a common material such as CMYK ink, or a special color ink such as green, brown, or purple.

[0024] In the present invention, the printed element (221) is composed of a figure consisting of either a line segment and a curve, or a combination thereof, in a direction different from the angle of the first line (211) and the second line (212). This is to prevent the printed element (221) from being extracted and the visible image from being visualized as noise when the latent image is visualized by the reading device described later, if the figure of the printed element (221) is composed of a figure that includes a line segment in the same direction as the angle of the first line (211) and the second line (212).

[0025] In this embodiment, as shown in the enlarged view of Figure 3, an example of a printed element (221) composed of curves will be described, specifically one composed of a "circle". In the form in which the printed element (221) is composed of a circle, the diameter of the circle is larger than the width of the first stroke (211) and the width of the second stroke (212). In this embodiment, the second printed pattern (22), in which multiple printed elements (221) are arranged, is a visible image in which the letter "C" can be seen with the naked eye.

[0026] Figure 4 is a schematic diagram illustrating a method for visualizing the latent image of the letter "A" from a first printed pattern (21). The first printed pattern (21) can be visualized using the reading device (100) shown in Figure 4. The reading device (100) is, for example, a smartphone. This smartphone has a camera function for capturing an image of the first printed pattern (21), an image processing function for processing the image captured by the camera function to visualize the latent image from the first printed pattern (21), and a display function for displaying the visualized latent image.

[0027] In this embodiment, the reading device (100) visualizes the latent image of the letter "A" from the first printed pattern (21) by reading the difference in angle between the first stroke (211) and the second stroke (212). Specifically, as described in Japanese Patent Publication No. 6976527, a differential filter is applied according to the angle of the first stroke (211) or the second stroke (212) arranged in each unit (210) of the first printed pattern (21) to create a difference in the number of white pixels in the output image. For example, the differential filter makes it less likely for the edges of the first stroke (211) to be emphasized, and more likely for the edges of the second stroke (212) to be emphasized.

[0028] Next, the reading device (100) averages the image output by the differential filter over a unit area and converts it into a density value. Finally, the reading device (100) displays the character "A", which is the first printed pattern (21), as a latent image on the screen (110). The reading device (100) may also be configured to acquire an image using, for example, a scanner connected to a computer, and then display the visualized image on a display screen after processing it with software installed on the computer.

[0029] In the latent image print (1) according to the first embodiment configured as described above, the printed element (221) is composed of a shape that does not interfere with the reading operation of the first line (211) and the second line (212) by the reading device (100), and is positioned in a location that does not affect the reading of the first line (211) and the second line (212). This makes it possible to improve the visibility of the visible image while ensuring the accuracy of latent image reading. Note that if the size of the printed element (221) (diameter in the case of a circle) is larger than the length of the first line (211) and the second line (212), the length of the first line (211) and the second line (212) extracted by the reading device (100) will be shorter, and the contrast of the visible latent image will decrease. For this reason, it is preferable that the size of the printed element (221) (diameter in the case of a circle) be half or less of the length of the first line (211) and the second line (212). Furthermore, it is preferable to set the size of the printed element (221) (diameter in the case of a circle) to one-third or less of the length of the first line (211) and the second line (212) because this provides a good balance between the latent image visualized by the reading device (100) and the visible image that can be seen with the naked eye.

[0030] Furthermore, the reading device (100) may display the latent image as a color image based on colors preset according to the angles of the first line (211) and the second line (212), as described in Japanese Patent Publication No. 7323112. Specifically, the reading device (100) converts the first line (211) to blue and the second line (212) to yellow, so that the letter "A" is visualized in blue and the area around it is visualized in yellow. According to Japanese Patent Publication No. 7323112, the lines constituting the first printed pattern (21) can also be configured to include three lines with different angles, and by coloring each of the lines with different angles with a different color, a colorful latent image can be visualized.

[0031] (Other examples of print elements) In the first embodiment, an example in which the printed element (221) is composed of a circle was described, but when the edges of the first line (211) and the second line (212) are extracted by the reading device (100), any shape that is not affected by the pattern of the latent image is acceptable. Other examples of the printed element (221) include, as shown in Figure 5(a), an example composed of a curve, which may be an "ellipse". Also, as an example consisting of line segments in directions different from the angles of the first line (211) and the second line (212), it may be a square with sides in directions different from the angles of the first line (211) and the second line (212), as shown in Figure 5(b). Furthermore, the shape of the printed element (221) may be a rectangle, a triangle, etc., as long as it is a shape with sides in directions different from the angles of the first line (211) and the second line (212) (not shown). Furthermore, the shape of the print element (221) may be composed of line segments and curves in directions different from the angles of the first line (211) and the second line (212), as shown in Figure 5(c). Note that the size (outline) of the print element (221) shown in Figure 5 is always larger than the width of the first line (211) and the second line (212). The meaning of "direction different from the angle of the lines" here is, using Figure 5(b) as an example, that in a configuration where the first line (211) is inclined at 45 degrees to the horizontal and the second line (212) is inclined at 135 degrees to the horizontal, the directions of the four sides constituting the square are angles different from 45 degrees and 135 degrees.

[0032] (Second Embodiment) In the second embodiment, the printed pattern (20) is configured such that the printed elements (221) constituting the second printed pattern (22) are adjacent to all the ends of the first lines (211) and second lines (212) constituting the first printed pattern (21). In the second embodiment, there are two ways in which the visible image formed by the second printed pattern (22) can be constructed, and these will be described in turn. The same reference numerals are used for components that are the same as those in the latent image printed material (1) according to the first embodiment described above, and detailed explanations are omitted.

[0033] Figure 6 is a diagram showing the first example of the configuration of a visible image by the second printed pattern (22), and is an enlarged view of a part of the printed area (11). In the first configuration of the visible image of the second embodiment, as shown in Figure 6, the printed elements (221) are adjacent at all ends of the first stroke (221) and the second stroke (212), and furthermore, the colors of the printed elements (221) are partially different in the second printed pattern (22). In Figure 6, the printed elements (221) of different colors are shown as code (221A) and code (221B), respectively. For example, if a blue printed element (221A) is formed corresponding to the area of ​​the letter "C" in the visible image, and the rest is a yellow printed element (221B), then an image can be seen in which the letter "C" is blue and the area around it is yellow.

[0034] Figure 6 illustrates an example in which a second printed pattern (22) is composed of two different colored printed elements (221A, 221B), but the second printed pattern (22) may be composed of three or more colored printed elements (221).

[0035] Furthermore, as shown in Figure 7, the print elements (221) may have different colors within a single print element (221). As examples of different colors within a single print element (221), Figure 7(a) shows an example of a print element (221) with different colors on the left and right sides, and Figure 7(b) shows an example of a print element (221) with three different colors. Note that the configuration of different colors within a single print element (221) is not limited to the examples shown in Figure 7, and the colors constituting the print element (221) may be made different as appropriate according to the colors of the pattern represented by the visible image.

[0036] Furthermore, as shown in Figure 8, the print element (221) may be composed of a collection of halftone dots (d). In this case, a single print element (221) is formed by arranging multiple halftone dots (d) inside the outline of a circular print element (221). Note that if the halftone dots (d) are arranged without gaps inside the outline of a circular print element (221), the configuration will be the same as the print element (221) shown in Figure 3. Figure 8(b) shows an example where there are more halftone dots (d) per unit area of ​​the print region (11) compared to the configuration in Figure 8(a), and Figure 8(c) shows an example where there are fewer halftone dots (d) per unit area of ​​the print region (11) compared to the configuration in Figure 8(a). When the visible image of the letter "C" is formed using any of the print elements (221) shown in Figures 8(a) to 8(c), the overall density of the visible "C" can be adjusted according to the number of halftone dots (d) arranged per unit area of ​​the print region (11). Furthermore, within the visible image of the letter "C", if the proportion of halftone dots (d) constituting the print element (221) is varied, as shown in Figures 8(a) to 8(c), it is possible to create variations in shade within the letter "C".

[0037] Furthermore, the printing element (221) may be composed of a collection of halftone dots (d) of different colors. Figure 8(d) shows an example in which the printing element (221) is composed of halftone dots formed by process CMYK inks. In Figure 8(d), halftone dots formed by cyan ink are denoted as code (d1), halftone dots formed by magenta ink as code (d2), halftone dots formed by yellow ink as code (d3), and halftone dots formed by black ink as code (d4). The configuration shown in Figure 8(d) is an example of a printing element (221) composed of halftone dots (d) of different colors. Similar to the configuration shown in Figure 7, the colors of the halftone dots (d) constituting the printing element (221) may be appropriately varied according to the colors of the pattern represented by the visible image. Note that the color of the halftone dots (d) for color representation of the visible image is not limited to CMYK inks, but may be formed by spot inks such as green, orange, and brown.

[0038] In the latent image print (1) according to the second embodiment configured as described above, the print elements (221A) and (221B) are composed of figures that do not interfere with the reading operation of the first line (211) and the second line (212) by the reading device (100), and are arranged in a location that does not affect the reading of the first line (211) and the second line (212). This makes it possible to improve the visibility of the visible image while ensuring the accuracy of reading the latent image.

[0039] Furthermore, in this embodiment, a printed element (221) is adjacent to the end of all the lines (211, 212). Therefore, it is possible to enhance the camouflage effect of the latent image pattern consisting of the first line (211) and the second line (212).

[0040] Figure 9 is a diagram showing a second example of the configuration of a visible image by the second printed pattern (22), and is an enlarged view of a part of the printed area (11). In the second configuration of the visible image of the second embodiment, as shown in Figure 9, the printed elements (221) are adjacent at all ends of the first stroke (211) and the second stroke (212), and furthermore, in the second printed pattern (22), the printed elements (221) have the same color and are partially different in size. In Figure 9, the printed elements (221) of different sizes are shown as symbols (221a) and (221b), respectively, and an example is shown where the diameter of printed element (221a) is larger than the diameter of printed element (221b). In this configuration, areas formed by larger diameter printing elements (221a) appear darker than areas formed by smaller diameter printing elements (221b). For example, if the letter "C" is formed by printing elements (221a), the letter "C" will appear darker than the surrounding area.

[0041] Figure 9 illustrates an example in which a second printed pattern (22) is composed of two printed elements (221a, 221b) of different sizes. However, by composing the second printed pattern (22) with three or more printed elements (221) of different sizes, the range of grayscale expression that the second printed pattern (22) can represent can be widened.

[0042] In the latent image printed matter (1) configured as described above, similar to the second embodiment described above, the printing elements (221a) and the printing elements (221b) are formed of a pattern that does not interfere with the reading operations of the first scanning line (211) and the second scanning line (212) by the reading device (100), and are arranged at locations that do not affect the reading of the first scanning line (211) and the second scanning line (212). Thereby, it becomes possible to improve the visibility of the visible image while ensuring the reading accuracy of the latent image. Also, the printing element (221a) or the printing element (222b) is adjacent to the ends of all the scanning lines (211, 212). Therefore, it is also possible to enhance the camouflage effect of the pattern of the latent image formed by the first scanning line (211) and the second scanning line (212).

[0043] (Third Embodiment) The third embodiment is a form in which the printing element (221) is constituted by a set of halftone dots (d) in the latent image printed matter (1) of the second embodiment. Further, it is a latent image printed matter (1) in which a latent image different from the latent image by the reading device (100) can be confirmed when observed using an infrared camera. Regarding the configuration of the first printed pattern (21), since it is the same as that of the first embodiment, the description thereof is omitted, and the configuration of the second printed pattern (22) will be described.

[0044] The configuration of the second printed pattern (22) in an example of the third embodiment will be described with reference to FIG. 10. Here, in the second printed pattern (22) shown in FIG. 10, an example of a visible image in which the character "C" is blue and the periphery thereof is yellow will be described, and an example in which the character "positive" can be confirmed when observed using an infrared camera.

[0045] As shown in the enlarged view of FIG. 10, in the region around the character "C", printing elements (221A, 221B) of different colors are arranged respectively. In the present embodiment, among the printing elements (221A), the printing element (221A) arranged in the region of the character "C" and overlapping with the character "positive" is, as shown in the enlarged view of FIG. 10(b), the dot (d1) formed by cyan ink for expressing the blue color of the character "C" and the dot (hereinafter referred to as "the first dot (B1)") formed by carbon black ink having infrared absorption characteristics are formed. On the other hand, the printing element arranged in the region of the character "C" and not overlapping with the character "positive" is, as shown in the enlarged view of FIG. 10(c), the dot (d1) for expressing the blue color of the character "C" and the dot (hereinafter referred to as "the second dot (B2)") formed by black ink obtained by mixing cyan ink, magenta ink and yellow ink which are visually recognized as the same black color as the first dot (B1). General cyan ink, magenta ink and yellow ink have infrared transmission characteristics, and the second dot (B2) is formed using ink having infrared transmission characteristics.

[0046] The printing element (221A) shown in FIG. 10(b) and the printing element (221A) shown in FIG. 10(c) have corresponding dots (d1) and corresponding first dots (B1) and second dots (B2), and are visually recognized as the same color, but in an infrared camera, only the first dot (B1) having infrared absorption characteristics is confirmed.

[0047] FIG. 10(d) is a diagram showing another example of the printing element (221A) that is visually recognized as having the same color as the printing element (221A) shown in FIG. 10(a). Halftone dots (d1) for expressing the blue color of the character "C", halftone dots formed by cyan ink having infrared transmission characteristics (hereinafter referred to as "second - 1 halftone dots (B2 - 1)"), halftone dots formed by magenta ink having infrared transmission characteristics (hereinafter referred to as "second - 2 halftone dots (B2 - 2)"), and halftone dots formed by yellow ink having infrared transmission characteristics (hereinafter referred to as "second - 3 halftone dots (B2 - 3)") are formed. As shown in FIG. 10(d), even when halftone dots (B2 - 1, B2 - 2, B2 - 3) are formed by cyan ink, magenta ink, and yellow ink, when observed visually, since the respective colors are mixed and visually recognized as black, it can be visually recognized in the same way as the first halftone dots (B1).

[0048] FIG. 11(a) is a diagram showing the configuration of a printing element (221B) that is arranged in a region around the character "C" and overlaps with the character "正". In this case, halftone dots (d3) formed by yellow ink for expressing the yellow around the character "C" and the first halftone dots (B1) formed by carbon black ink having infrared absorption characteristics are formed. On the other hand, the printing element (221B) that is arranged in a region around the character "C" and does not overlap with the character "正" is, as shown in the enlarged view of FIG. 11(b), halftone dots (d3) for expressing the yellow around the character "C" and second halftone dots (B2) formed by black ink obtained by mixing cyan ink, magenta ink, and yellow ink that are visually recognized as the same black color as the first halftone dots (B1). Also, for the second halftone dots (B2) shown in FIG. 11(b), as shown in FIG. 11(c), second - 1 halftone dots (B2 - 1) formed by cyan ink having infrared transmission characteristics, second - 2 halftone dots (B2 - 2) formed by magenta ink having infrared transmission characteristics, and second - 3 halftone dots (B2 - 3) formed by yellow ink having infrared transmission characteristics may be formed.

[0049] The printed element (221B) shown in Figure 11(a) and the printed elements (221B) shown in Figures 11(b) and 11(c) appear to be the same color, but an infrared camera can only detect the first halftone dot (B1) which has infrared absorption properties.

[0050] In the latent image printed material (1) according to the embodiment configured as described above, the latent image consisting of the first line (211) and the second line (212) can be visualized by using a reader (100). Furthermore, the visible image consisting of the printed elements (221A) and (221B) can be viewed with the naked eye. In addition, by photographing the latent image printed material (1) with an infrared camera, the latent image consisting of the first halftone dot (B1) formed with infrared-absorbing ink can be visualized. In particular, the latent image printed material (1) of the third embodiment can enhance its anti-counterfeiting effect by including printed elements (221) that can be displayed with a special camera in this way.

[0051] In the third embodiment, the latent image print (1) contains, in detail, a first black halftone dot (B1) and a second black halftone dot (B2) in the printed elements (221A, 221B). As a result, the visible image of the letter "C" is perceived as a dark blue, and the area around the letter "C" is perceived as a dark yellow. However, if the size of the halftone dots (B1, B2) is smaller than the size of the halftone dots (d1, d3), the effect is less. Therefore, if the color of the visible image is prioritized, the size of the halftone dots (B1, B2) should be made smaller than the size of the halftone dots (d1, d3), and if the contrast of the latent image obtained by an infrared camera is prioritized, the size of the halftone dots (B1, B2) should be made larger.

[0052] Furthermore, in order to briefly explain the configuration of the visible image of the latent image print (1) of the third embodiment, an example was given in which the letter "C" and its surroundings are composed of two different colors. However, the method is not limited to this, and halftone dots (d) of each color can be formed according to the colors of the design represented by the visible image. For example, a single print element (221) may be composed of halftone dots (d) of multiple colors. Also, the color of the halftone dots (d) for color representation of the visible image is not limited to CMYK inks, but may be formed by spot color inks such as green, brown, or purple.

[0053] Furthermore, regarding the configuration of the latent image print (1) of the third embodiment, an example was described in which a first halftone dot (B1) formed by carbon black ink and a second halftone dot (B2) formed by cyan ink, magenta ink, and yellow ink having infrared transmission properties were used. However, it is also acceptable to have a configuration in which only the first halftone dot (B1) is formed by an ink having infrared absorption properties, and the second halftone dot (B2) has infrared transmission properties and is visible as the same color as the first halftone dot (B1). For example, the second halftone dot (B2) may be formed by a black ink having infrared transmission properties, such as chromofine black. Alternatively, for example, the first halftone dot (B1) may be formed by a chromatic ink such as phthalocyanine green or cobalt blue that has infrared absorption properties, and the second halftone dot (B2) may be formed by an ink having infrared transmission properties that is visible as the same color as the first halftone dot (B1).

[0054] Furthermore, while the latent image print (1) of the third embodiment was described as comprising a first halftone dot (B1) having infrared absorption properties and a second halftone dot (B2) that is visible as the same color as the first halftone dot (B1), the properties of the first halftone dot (B1) in the latent image print (1) of the present invention are not limited to infrared absorption properties. For example, the first halftone dot (B1) can be formed by mixing a light-emitting pigment such as a fluorescent pigment, phosphorescent pigment, or luminescent pigment, or a functional material such as an IR-absorbing pigment, photochromic pigment, thermochromic material, or other thermochromic material into the ink, and then forming a second halftone dot (B2) that is visible as the same color as the first halftone dot (B1) but does not have the same properties as the first halftone dot (B1). [Explanation of Symbols]

[0055] 1. Latent image print 10 Base material 11 Print area 20 Print Patterns 21 First Print Pattern 22. Second printing pattern 100 Reader 211 First stroke 212 Second stroke 221, 221A, 221B printing elements d Halftone dots d1, d'1 Halftone dots (cyan) d2, d'2 Halftone dots (magenta) d3, d'3 halftone dots (yellow) d4 halftone (black) B1 First halftone dot (carbon black) B2 Second halftone dot (CMY mixed black)

Claims

1. A latent image print comprising a first printed pattern in which multiple lines of a different color from the substrate are arranged in at least a portion of the printing area of ​​the substrate and are visible as a uniform density, wherein the lines arranged in the printing area have partially different angles, and the latent image is made visible by a reading device that reads the difference in the angles of the lines, A latent image print characterized in that a second print pattern is formed by placing a graphic print element consisting of a line segment, a curve, or a combination thereof, in a direction different from the angle of the line, adjacent to at least one end of the plurality of lines constituting the first print pattern.

2. The printing elements are arranged adjacent to the ends of all the lines that constitute the first printed pattern. The latent image print according to claim 1, characterized in that the print element is partially different in color and size.

3. In a part of one of the aforementioned printing elements, a first halftone dot is formed by an ink having infrared absorption properties, The latent image print according to claim 2, characterized in that a second halftone dot is formed in a printing element different from the aforementioned one printing element, and is made of an ink having infrared transmission properties, and is visible as the same color as the first halftone dot.

Images