Printed matter and verification method of validity of printed matter

Abstract

To provide a printed matter having a high counterfeit prevention effect compared with conventional configurations.SOLUTION: A printed matter includes, on a surface of a light-colored base material, a first two-dimensional code 4 printed in a dark color and not absorbing infrared light in a prescribed band and a second two-dimensional code 3 printed with infrared light absorbing ink 22 absorbing infrared light in a prescribed band. The second two-dimensional code 3 is printed to overlap the first two-dimensional code 4 by using colored ink as the infrared light absorbing ink 22, so that the dark color of the first two-dimensional code 4 is not printed, and a portion printed with the infrared light absorbing ink 22 exhibits a prescribed light color that is easily distinguishable from the light color of the surface of the base material.SELECTED DRAWING: Figure 3

Description

[Technical Field]

[0001] The present invention relates to a printed matter that is required to be protected from counterfeiting. [Background technology]

[0002] In order to prevent counterfeiting of printed materials such as tickets, it has been proposed to print a visible two-dimensional code that is easy to read under visible light illumination but difficult to read under near-infrared light illumination, and a transparent two-dimensional code that is difficult to read under visible light illumination but easy to read under near-infrared light illumination, and to record information in each two-dimensional code to verify the authenticity of the printed material (see Patent Document 1). [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Application Publication No. 2018-089840 Summary of the Invention [Problem to be solved by the invention]

[0004] The transparent two-dimensional code disclosed in Patent Document 1 is difficult to read when illuminated with visible light, and can only be printed using transparent, infrared-absorbing ink. This makes it more difficult to counterfeit than printed matter printed with only a visible two-dimensional code. However, with advances in printing technology, there is a demand for printed matter that is even more difficult to counterfeit.

[0005] The present invention has been made in view of the above-mentioned current situation, and aims to provide a printed matter that has a higher anti-counterfeiting effect than the above-mentioned conventional configurations. [Means for solving the problem]

[0006] The present invention is a printed matter comprising a first two-dimensional code that does not absorb infrared light in a predetermined band and is printed in a dark color on the surface of a light-colored substrate, and a second two-dimensional code that is printed in infrared light-absorbing ink that absorbs infrared light in the predetermined band, wherein the infrared light-absorbing ink is colored ink, the second two-dimensional code is printed so as to overlap the first two-dimensional code, the dark color of the first two-dimensional code is not printed, and the area where the infrared light-absorbing ink is printed exhibits a predetermined light color that is easily distinguishable from the light color of the substrate surface.

[0007] The authenticity of the printed matter of the present invention can be confirmed not only by (1) whether proper information can be read from the first two-dimensional code under visible light illumination and (2) whether proper information can be read from the second two-dimensional code under infrared light illumination, but also by (3) whether the color of the infrared-absorbing ink appears under visible light illumination. In other words, to counterfeit the printed matter of the present invention, it is not enough to simply print the second two-dimensional code with infrared-absorbing ink; the color of the infrared-absorbing ink must also be reproduced, making it more difficult to counterfeit than conventional configurations. Furthermore, with the present invention, the color of the infrared-absorbing ink can be confirmed under visible light illumination, so the presence of the second two-dimensional code can be easily confirmed even without infrared light illumination.

[0008] The infrared light absorbing ink is light in the light areas of the first two-dimensional code and dark in the dark areas of the first two-dimensional code, so it does not interfere with the reading of the first two-dimensional code. Also, under visible light illumination, the pattern of the first optical code interferes with the reading of the second two-dimensional code, so the recorded data of the second two-dimensional code cannot be read under visible light illumination.

[0009] In the present invention, a configuration is proposed in which the infrared light absorbing ink is printed so that at least a specific portion of the first two-dimensional code exhibits the predetermined bright color.

[0010] In this configuration, the first two-dimensional code is detected from an image captured under visible light illumination, and the color of a specific portion of the first two-dimensional code in the image is determined, making it possible to easily determine whether the second two-dimensional code has been printed properly.

[0011] In addition, the present invention proposes a configuration in which the second two-dimensional code is printed so that it overlaps almost entirely with the first two-dimensional code.

[0012] With this configuration, it is possible to reliably prevent the second two-dimensional code from being detected under visible light illumination, and it is also possible to minimize the printing area of ​​the first two-dimensional code and the second two-dimensional code on the printed material, thereby minimizing the range that needs to be imaged when reading the two two-dimensional codes.

[0013] In addition, the present invention proposes a configuration in which the size of each cell constituting the second two-dimensional code is equal to or larger than the size of each cell constituting the first two-dimensional code.

[0014] Because the imaging elements of typical cameras are sensitive to invisible light such as near-infrared light, a typical camera can capture an image of the second two-dimensional code, but the image quality will be coarser than when capturing an image of the first two-dimensional code under visible light illumination. With this configuration, the cells of the second two-dimensional code are sized to be easier to distinguish than the cells of the first two-dimensional code, making it possible to compensate for the decrease in readability due to the coarse image quality and equalize the readability of the first and second two-dimensional codes.

[0015] In addition, in the present invention, a configuration is proposed in which the first two-dimensional code is printed in almost black on the almost white surface of the substrate, and the predetermined light color has a reflection density (OD value) within the range of 0.03 to 0.6.

[0016] The "predetermined bright color" according to the present invention is required to be a color that can be reliably determined as a bright color (bright cell) when imaged with a typical two-dimensional code reader. According to the inventor's research, when the first two-dimensional code is printed in almost black, the "predetermined bright color" preferably has a reflection density (OD value) of 0.6 or less. Furthermore, when the color of the substrate surface is almost white, the "predetermined bright color" preferably has a reflection density (OD value) of 0.03 or more. Such a color can be easily distinguished from the white color of the substrate surface.

[0017] The present invention can be suitably applied to tickets that are susceptible to counterfeiting, such as train tickets and admission tickets. When the present invention is applied to a ticket, a configuration is proposed in which information for verifying the validity of the ticket is recorded in the first two-dimensional code and the second two-dimensional code, respectively.

[0018] In addition, as another aspect of the present invention, a method for verifying the validity of the above-mentioned printed matter is proposed, which includes a first step of capturing an image including the first two-dimensional code and the second two-dimensional code under illumination with visible light, a second step of detecting the first two-dimensional code included in the image, and a third step of determining whether the second two-dimensional code is printed so as to overlap the first two-dimensional code based on the color tone of the portion of the first two-dimensional code in the image that exhibits the specified light color.

[0019] According to this validation method, it is possible to determine whether or not a second two-dimensional code is printed based only on an image captured under visible light illumination before capturing an image under infrared light illumination. [Effects of the Invention]

[0020] As described above, the printed matter of the present invention can provide improved anti-counterfeiting effects compared to conventional configurations in which a transparent two-dimensional code that is difficult to see under visible light illumination is printed.

[0021] Furthermore, according to the method for verifying a printed matter of the present invention, it becomes possible to easily verify whether a printed matter is counterfeit. [Brief explanation of the drawings]

[0022] [Figure 1] 1A is a front view of the anti-counterfeit ticket 1 of the embodiment imaged under white light illumination, and FIG. 1B is a front view of the anti-counterfeit ticket 1 of the embodiment imaged under near-infrared light illumination. [Figure 2] 1 is an exploded perspective view of a counterfeit-proof ticket 1 according to an embodiment of the present invention. [Figure 3] (A) is a surface view of the two-dimensional code printing section 6 before the visible code 4 is printed, and (B) is a surface view of the two-dimensional code printing section 6 after the visible code 4 is printed. [Figure 4] FIG. 2 is a system configuration diagram of a ticket management system 9. [Figure 5] 10 is a flowchart showing the control process of ticket issuing processing. [Figure 6] FIG. 2 is a block diagram of the ticket gate 12. [Figure 7] 10 is a flowchart showing the control process of ticket gate processing. [Figure 8] 10 is a flowchart showing the control process content of the validity confirmation process. DETAILED DESCRIPTION OF THE INVENTION

[0023] The embodiments of the present invention will be described with reference to the following examples. In the following examples, the first two-dimensional code according to the present invention corresponds to the visible code 4, and the second two-dimensional code according to the present invention corresponds to the infrared code 3. Furthermore, the infrared light in the predetermined band according to the present invention corresponds to near-infrared light. Furthermore, the "light color of the substrate surface" according to the present invention corresponds to white, and the "predetermined light color" according to the present invention corresponds to bright yellow-green.

[0024] As shown in Fig. 1(A), the printed matter of this embodiment is a counterfeit-proof railway ticket 1. On the counterfeit-proof ticket 1, two-dimensional codes 3 and 4 for verifying the validity of the ticket are printed in a two-dimensional code printing area 6 on the front side of the base material 2. Furthermore, text information 5 indicating ticket information is printed in areas other than the two-dimensional code printing area 6. Although not shown in the figure, the back side of the counterfeit-proof ticket 1 is plain white.

[0025] As shown in FIG. 1(A), two types of two-dimensional codes 3 and 4 are printed on the two-dimensional code printing unit 6 so that they overlap almost entirely. One of the two-dimensional codes is a black-and-white visible code 4 that can be read under visible light illumination. The other two-dimensional code is an infrared code 3 that can be read under near-infrared light illumination. Specifically, the visible code 4 is a typical QR Code (registered trademark) that complies with the standard (JIS X 0510) and is composed of a pattern of light and dark cells. While the visible code 4 is composed of a pattern of light and dark cells, the infrared code 3 is composed of a pattern of first cells with high near-infrared light reflectivity and second cells with low near-infrared light reflectivity. The infrared code 3 complies with the QR code standard (JIS X 0510) except for being composed of two types of cells with different near-infrared light reflectivity.

[0026] The base material 2 of the anti-counterfeit ticket 1 is plain white thermal paper with a thermal layer 20 on the front side. As shown in Figure 2, the visible code 4 is formed by using a thermal printer to thermally color the thermal layer 20 black in the dark cell areas. Meanwhile, the infrared code 3 is formed by solid printing infrared light absorbing ink 22, which has near-infrared light absorption properties, in the second cell areas on top of the thermal layer 20 of the base material 2.

[0027] The thermosensitive layer 20 on the front side of the substrate 2 reflects near-infrared light in the same way in both the uncolored white parts and the thermocolored black parts. For this reason, in an infrared image taken of the anti-counterfeit ticket 1 under near-infrared light illumination, the pattern of the visible code 4 disappears from the two-dimensional code printed area 6, and only the pattern of the infrared code 3 appears, as shown in Figure 1(B). Note that the text information 5 is printed on the thermosensitive layer 20 by a thermal printer, so the text information 5 also disappears in the infrared image of Figure 1(B).

[0028] The infrared light absorbing ink 22 forming the infrared code 3 is a yellow-green ink that transmits the undercolor. As shown in Figure 3, the areas where the infrared light absorbing ink 22 is solid printed and overlaps with the white parts of the thermosensitive layer 20 appear bright yellow-green (shown as gray in Figures 1 to 3) due to mixing with the undercolor, and the areas where it overlaps with the black parts of the thermosensitive layer 20 appear black due to mixing with the undercolor.

[0029] 3(B), in the black portion of the thermosensitive layer 20, the portion printed with the infrared light-absorbing ink 22 and the portion not printed are both black, making it difficult to distinguish between them under visible light illumination. Since the infrared code 3 is printed so that it entirely overlaps the visible code 4, with this configuration, the infrared code 3 is hidden by the printing pattern of the visible code 4 under visible light illumination, making it difficult to read.

[0030] On the other hand, even if the infrared code 3 (infrared light absorbing ink 22) is printed so as to overlap the visible code 4, the black parts of the thermosensitive layer 20 appear dark (black) and the white parts of the thermosensitive layer 20 appear light (white or light yellow-green), so in an image captured under visible light illumination, the light and dark cells of the visible code 4 can be easily distinguished by the difference in brightness.

[0031] As described above, in an image captured under visible light illumination, the anti-counterfeit ticket 1 of this embodiment allows the light-colored cells of the visible code 4 in the two-dimensional code printed area 6 to be easily distinguished by differences in brightness, making it possible to read the information recorded in the visible code 4 based on this image. Furthermore, in an infrared image captured under near-infrared light illumination of the anti-counterfeit ticket 1, the pattern of the first and second cells of the infrared code 3 appears as a light-dark pattern in the two-dimensional code printed area 6, as shown in FIG. 1(B), making it possible to read the information recorded in the infrared code 3 based on this infrared image. Furthermore, the anti-counterfeit ticket 1 of this embodiment provides superior anti-counterfeiting effects compared to tickets on which only the visible code 4 is printed, because it is difficult to read the infrared code 3 in an image captured under visible light illumination and it is difficult to reproduce the pattern of the infrared code 3 with ordinary printer ink.

[0032] In particular, in this embodiment, the portions of the infrared code 3 where the infrared-absorbing ink 22 is printed in the light-colored cells of the visible code 4 (the uncolored portions of the thermosensitive layer 20) are bright yellow-green. Because this color is easily distinguishable from the white surface of the substrate 2, in this embodiment, whether a specific infrared-absorbing ink 22 is printed can be determined by determining whether the light-colored cells of the visible code 4 contain yellow-green. Therefore, the validity of the anti-counterfeit ticket 1 of this embodiment can be verified not only by (1) whether the visible code 4 contains appropriate information and (2) whether the infrared code 3 contains appropriate information, but also by (3) whether the light-colored cells of the visible code 4 contain yellow-green. In other words, to counterfeit the anti-counterfeit ticket 1 of this embodiment, it is not enough to simply print the infrared code 3 with a general infrared-absorbing ink; it is also necessary to obtain infrared-absorbing ink 22 of a specific color (yellow-green). Therefore, the anti-counterfeit ticket 1 of this embodiment is more difficult to counterfeit than the conventional configuration.

[0033] Furthermore, in this embodiment, infrared light absorbing ink 22 is always printed in a specific portion of the visible code 4 under visible light illumination. Specifically, as shown in Fig. 3, by arranging the eye-shaped position detection patterns 23, 24 of the infrared code 3 and the visible code 4 so that they overlap, infrared light absorbing ink 22 is always printed in the upper left corner of the light-colored frame-shaped portion that constitutes the upper left position detection pattern 24, and this portion appears yellowish-green. With this configuration, it is possible to easily determine whether infrared light absorbing ink 22 is printed or not by simply detecting the visible code 4 from an image captured under visible light illumination and determining the color of the specific portion.

[0034] In this embodiment, the infrared code 3 and the visible code 4 are printed to be approximately the same size and almost entirely overlapping on the two-dimensional code printing section 6. This configuration reliably prevents the infrared code 3 from being detected under visible light illumination, and also minimizes the area of ​​the two-dimensional code printing section 6. Furthermore, the imaging range required to read the infrared code 3 and the visible code 4 can be minimized.

[0035] Furthermore, in this embodiment, the infrared code 3 is printed as a lower version of the QR code (having a smaller total number of cells) than the visible code 4, and as a result, the size of each cell of the infrared code 3 is larger than that of the visible code 4. Since the infrared light image used to read the infrared code 3 generally has lower image quality than an image captured under visible light illumination, this configuration makes it possible to make the readability of the infrared code 3 closer to that of the visible code 4 by compensating for the lower image quality of the infrared light image with the larger cells.

[0036] Furthermore, in this embodiment, the infrared code 3 is printed with infrared light absorbing ink 22 on top of the thermosensitive layer 20 on which the visible code 4 is printed, so that the image of the infrared code 3 can be captured more clearly than when the infrared code 3 is printed on a layer below the visible code 4, and the readability of the infrared code 3 can be made closer to that of the visible code 4. Note that, since the visible code 4 is printed on the thermosensitive layer 20 by a thermal printer, the visible code 4 can be printed on the thermosensitive layer 20 after the infrared light absorbing ink 22 has been printed on the thermosensitive layer 20.

[0037] A specific example of how the anti-counterfeit ticket 1 of this embodiment can be used will be described below. 4 is a schematic diagram of a railway ticket management system 9 that uses the counterfeit-proof ticket 1 of this embodiment. The ticket management system 9 comprises an information management server 10 that manages information on the counterfeit-proof ticket 1, a ticket issuing machine 11 that issues the counterfeit-proof ticket 1, and a ticket gate 12, all connected via a communication line 13.

[0038] In the ticket management system 9, in addition to the anti-counterfeit ticket 1 of the embodiment, a regular ticket is also used in which only the visible code 4 is printed on the two-dimensional code printing section 6, and no infrared code 3 is printed. Specifically, high-value tickets that are more likely to be counterfeited or copied are issued as anti-counterfeit tickets 1, and low-value tickets that are less likely to be counterfeited or copied are issued as regular tickets, which have low issuance costs.

[0039] A ticket ID is recorded in the visible code 4 of the anti-counterfeit ticket 1 and the regular ticket. The ticket ID is a unique ID assigned to each ticket when it is issued, and is made up of a combination of the ticket issuing machine ID, the date of issuance, and a serial number. The ticket issuing machine ID is an ID assigned to each ticket issuing machine 11, and the serial number is a consecutive number assigned to each ticket issued by that ticket issuing machine 11.

[0040] A passcode is recorded in the infrared code 3 of the anti-counterfeit ticket 1. The passcode is a number that the information management server 10 uses to verify the authenticity of the ticket paper.

[0041] A method for issuing tickets in the ticket management system 9 will now be described. The anti-counterfeit ticket 1 and regular tickets are issued by a common ticket issuing machine 11. The ticket issuing machine 11 is equipped with a control computer and a thermal printer for printing the visible code 4 and character information 5. Regular paper and special paper are loaded into the ticket issuing machine 11.

[0042] Regular paper is printing paper on which the infrared code 3 is not printed on the base material 2. When issuing a regular ticket, the ticket issuing machine 11 prints a visible code 4 that records the ticket ID in the two-dimensional code printing section 6 of the regular paper, and also prints text information 5 in the other parts.

[0043] The special paper is printed paper on which an infrared code 3 recording a passcode has been printed in advance on the base material 2. When issuing an anti-counterfeit ticket 1, a visible code 4 is printed on the thermosensitive layer 20 so as to overlap the infrared code 3 already printed on the special paper, and text information 5 is printed in the remaining portion. In this way, by preparing special paper on which the infrared code 3 has been printed in advance, the anti-counterfeit ticket 1 can be easily issued in the same way as a regular ticket, simply by later printing the visible code 4 and text information 5 with a thermal printer.

[0044] 5 is a flowchart showing the control content of the ticket issuing process executed by the ticket issuing machine 11. The ticket issuing process is executed by the control computer of the ticket issuing machine 11 when payment for the ticket purchase is completed and the ticket is issued to the user. In the ticket issuing process, first, a ticket ID is assigned to the ticket to be issued (S1). Specifically, a ticket ID is generated by combining the ticket issuing machine ID, the date of issuance, and a serial number. Next, data for a visible code 4 that records the assigned ticket ID is generated (S2), and data for character information 5 to be printed on the ticket is also generated (S3). The ticket issuing machine 11 then determines whether the ticket to be issued is a counterfeit-proof ticket 1 (S4). If the ticket to be issued is a regular ticket, the generated visible code 4 and character information 5 are printed on regular paper using a thermal printer (S5, S6), and the printed regular ticket is sent to the receipt slot of the ticket issuing machine 11 (S9). On the other hand, if the ticket to be issued is a counterfeit-proof ticket 1, the generated visible code 4 and character information 5 are printed on special paper using a thermal printer (S7, S8). Note that the visible code 4 is printed so as to be appropriately overlapped with the already printed infrared code 3, as described above. Then, the printed anti-counterfeit ticket 1 is sent to the receiving port of the ticket issuing machine 11 (S9).

[0045] When the ticket issuing machine 11 issues a ticket through the above ticket issuing process, it transmits the ticket information of the ticket (ticket ID, expiration date, permitted boarding area, fare, passenger classification, etc.) to the information management server 10. The information management server 10 stores the ticket information received from the ticket issuing machine 11 in a database.

[0046] The ticket gate 12 is an automatic ticket gate that is compatible with both counterfeit-proof tickets 1 and regular tickets. As shown in Fig. 6, the ticket gate 12 includes a control computer 14, a gate opening / closing device 15, a ticket imaging device 16, an alarm device 18, and a communication device 19.

[0047] The ticket imaging device 16 is equipped with a transparent reading table on which the ticket is placed, a lighting device that illuminates the reading table from below, and a camera that captures an image of the ticket placed on the reading table, and is configured to output the image captured by the camera to the control computer 14 at regular intervals.

[0048] The lighting device is equipped with a normal light source that emits white light and a special light source that emits near-infrared light, and by switching the light source to be turned on in accordance with commands from the control computer 14, the reading table is selectively illuminated with white light or near-infrared light.

[0049] The camera is positioned with its focus on the reading table, captures images of the reading unit at predetermined intervals, and outputs the captured images to control computer 14. Under white light illumination (when the normal light source is on), the camera captures a general color image and outputs it to control computer 14. Since the camera's imaging element is sensitive not only to visible light but also to near-infrared light, under near-infrared light illumination (when the special light source is on), the camera captures a near-infrared image and outputs it to control computer 14.

[0050] When an image of the two-dimensional code printed section 6 of the ticket is input from the ticket imaging device 16, the control computer 14 reads the information recorded in the QR code in the image and requests the information management server 10 via the communication device 19 to confirm the validity of the ticket. In response to the validity confirmation request from the ticket gate 12, the information management server 10 compares the transmitted ticket ID with the ticket information in its database, replies to the ticket gate 12 with a response of "valid" or "invalid," and updates the ticket information in the database as necessary. If the result of the validity confirmation is "valid," the control computer 14 then activates the gate opening / closing device 15 to open the gate of the ticket gate 12. On the other hand, if the result of the validity confirmation is "invalid," the notification device 18 notifies the user of an error.

[0051] FIG. 7 is a flowchart showing the control content of the decryption process executed by the control computer 14 of the ticket examiner 12 at the time of ticket examination. In the ticket inspection process, the control computer 14 first turns on the illumination device of the ticket imaging device 16 with a normal light source (S50). If a color image including a QR code (visible code 4) is detected from the color image input from the ticket imaging device 16 (S51: Yes), the control computer 14 reads the recorded information (ticket ID) of the visible code 4 (S52) and crops the color image of the visible code 4 from the color image (S53). The cropped image does not need to include the entire visible code 4; it is sufficient if it includes a specific portion that allows the information management server 10 to determine whether or not the color of the infrared light-absorbing ink 22 is present. The control computer 14 then transmits the ticket ID read from the visible code 4 and the cropped image to the information management server 10, requesting confirmation of the validity of the ticket (S54).

[0052] In the next step S55, it is determined whether a passcode has been requested by the information management server 10. If the ticket for which validation has been requested is a counterfeit-proof ticket 1, a passcode is requested. If a passcode has been requested (S55: Yes), the control computer 14 turns on the special light source of the ticket imaging device 16 (S56). Then, if a QR code (infrared code 3) is read from the infrared light image input from the ticket imaging device 16 (S57: Yes), the control computer 14 reads the passcode read from the infrared code 3 and transmits it to the information management server 10 (S59). On the other hand, if a certain period of time has passed without the QR code (infrared code 3) being read (S58: Yes), an error is reported (S62).

[0053] If the result of the validity check notified by the information management server 10 is "valid" (S60: Yes), the control computer 14 opens the gate of the ticket gate 12 to allow the person to pass through the gate (S61). On the other hand, if the result of the validity check is "invalid" (S60: No), an error is reported (S62).

[0054] FIG. 8 is a flowchart showing the control content of the validity confirmation process executed by the information management server 10 when confirming the validity of a ticket. In the validity confirmation process, the information management server 10 first waits until a validity confirmation request is received from the ticket gate 12 (S71). If a validity confirmation request is received, the information management server 10 compares the transmitted ticket ID with the ticket information in the database to determine whether the ticket with that ticket ID is valid (S72). If the information management server 10 determines that the ticket ID is invalid (S73: No), it notifies the ticket gate 12 that requested the validity confirmation of the confirmation result that the ticket is "invalid." On the other hand, if the information management server 10 determines that the ticket ID is valid (S73: Yes) and that the ticket associated with that ticket ID is not a counterfeit-proof ticket 1 (a regular ticket) (S74: No), it updates the ticket information in the database (S81) and notifies the ticket gate 12 that requested the validity confirmation of the confirmation result that the ticket is "valid" (S82).

[0055] Furthermore, if it is determined that the ticket ID is valid (S73: Yes) and that the ticket associated with that ticket ID is a counterfeit-proof ticket 1 (S74: Yes), it checks whether a specific color (bright yellow-green or a color similar to it) is included in a specific portion of the image of the visible code 4 received from the ticket gate 12 (S75). Specifically, it is determined that the specific color is included if the specific portion includes pixels with RGB values ​​in the numerical range corresponding to the specific color. If it is determined that the specific color is not included (S76: No), it notifies the ticket gate 12 that requested the validity check of the ticket as being "invalid."

[0056] On the other hand, if it is determined in step S76 that the ticket has a specific color, the ticket gate 12 that requested the validation is requested to transmit a passcode (S77). The transmitted passcode is then compared with a specified value (S78, S79), and if it does not match the specified value (S80: No), the ticket gate 12 that requested the validation is notified of the confirmation result that the ticket is invalid. On the other hand, if the passcode matches the specified value (S80: Yes), the ticket information in the database is updated (S81), and the ticket gate 12 that requested the validation is notified of the confirmation result that the ticket is valid (S82).

[0057] As described above, when the counterfeit-proof ticket 1 of this embodiment is placed on the reader of the ticket gate 12, the validity of the counterfeit-proof ticket 1 is confirmed by the following (1) to (3). (1) Checking the ticket ID recorded in the visible code 4 (2) Verification of the passcode recorded on the infrared code 3 (3) Check whether a specific part of the color image contains yellow-green pixels. For this reason, in order to counterfeit the anti-counterfeit ticket 1 of this embodiment, it is not enough to simply print the infrared code 3 with ordinary infrared-absorbing ink, but it is also necessary to obtain a specific color of infrared-absorbing ink 22. Therefore, the anti-counterfeit ticket 1 of this embodiment is more difficult to counterfeit than the conventional configuration. In particular, the above-mentioned ticket inspection process and validity confirmation process have the advantage that by checking (3) above using a color image captured under white light illumination, it is possible to determine whether or not the infrared code 3 is printed on the ticket without capturing an infrared light image.

[0058] The method for verifying the validity of a printed matter of the present invention is realized by the ticket examination process (FIG. 7) of the ticket examination machine 12 and the validity confirmation process (FIG. 8) of the information management server 10. The first and second steps of the present invention are realized in steps S50 to S52 of the ticket examination process (FIG. 7). Meanwhile, the third step of the present invention is realized by S75 of the validity confirmation process (FIG. 8).

[0059] <Test item> The anti-counterfeit ticket 1 of the above embodiment was produced as a prototype under the following conditions. 1. Base material Material: plain white thermal paper Reflection density of uncolored area (white): 0.02 to 0.11 (OD value) Reflection density of colored area (black): 1.3 (OD value) 2. Visible Code Size: 2cm x 2cm Format: QR code (version 3) Printing method: Thermal printing in black on the thermal layer 3. Infrared Code Size: 1.8cm x 1.8cm Format: QR code (version 1) Printing method: Solid printing of yellow-green infrared absorbing ink 4. Placement of QR code The visible code was printed so as to overlap the entire infrared code, and the infrared-absorbing ink was aligned so that the printed portion appeared in the bright colored portion of the position detection pattern at the upper left of the visible code. 5. Print density of infrared absorbing ink Several prototypes were made using infrared absorbing ink with different print densities. The reflection density (OD value) of the uncolored portion of the substrate was measured for the infrared-absorbing ink printed portion of each test sample. Note that all OD values ​​were measured for K (total density) of the CMYK colors. As a result, the test sample with the lightest print density was 0.02, and the test sample with the darkest print density was 0.8.

[0060] <Test 1> For the test samples, color images of the two-dimensional code printed on the test samples were captured under white light illumination, and the QR code contained in the captured color image was attempted to be read using a general-purpose QR code reading program. As a result, the information recorded in the visible code was read for all test samples, but the information recorded in the infrared code was not read. This result suggests that even if a light-colored infrared code is printed over a dark-colored visible code, the visible code can be read from an image captured under visible light illumination, but the infrared code cannot be read from the same image. However, reading errors were confirmed for test samples where the reflection density (OD value) of the infrared-absorbing ink printed area exceeded 0.6. This suggests that if the reflection density (OD value) of the color of the infrared-absorbing ink printed area becomes too high, it becomes difficult to read the visible code 4.

[0061] <Test 2> For the test products, an infrared image of the two-dimensional code printed area was captured under near-infrared light illumination, and an attempt was made to read the QR code contained in the captured image using the same QR code reading program as in Test 1. As a result, the information recorded in the infrared code was read for all test products, but the information recorded in the visible code was not read.

[0062] <Test 3> A color image of the printed two-dimensional code of the test product was captured under white light illumination. A comparison product was also prepared, with only a visible code printed and no infrared code printed. A color image of the printed two-dimensional code of the comparison product was also captured under white light illumination. Based on the RGB values ​​of the pixels in the color images of the test product and comparison product, it was determined whether a bright yellow-green color was present in the specified detection target area (the light-colored portion of the position detection pattern in the upper left corner of the visible code). As a result, test samples with a reflection density (OD value) of the infrared-absorbing ink printed area exceeding 0.03 were determined to contain bright yellow-green in the designated detection area. On the other hand, test samples with a reflection density (OD value) of the infrared-absorbing ink printed area below 0.03 and the comparison sample were determined not to contain bright yellow-green in the designated detection area. These results suggest that by increasing the reflection density (OD value) of the printed area with infrared light absorbing ink, it can be easily distinguished from the white of the substrate.

[0063] Although examples of the present invention have been described above, the embodiments of the present invention are not limited to the configurations of the above examples, and can be modified as appropriate within the scope of the invention.

[0064] For example, the printed matter of the present invention can be applied to various types of vouchers, such as tickets other than railway tickets, certificates, and permits, and the information recorded in the two-dimensional code of the present invention is not limited to the ticket ID and passcode mentioned above, but can be any information that can be used to confirm the validity and authenticity of the printed matter.

[0065] Furthermore, although the infrared code 3 in the above embodiment is printed in a bright yellow-green color with the infrared light absorbing ink 22, the color of the infrared code 3 can be changed as appropriate as long as it is a bright color that is easily distinguishable from the surface color of the substrate 2. In other words, the surface color of the substrate 2 is not limited to white, and may be a color (such as light gray) that is easily distinguishable from the color of the infrared code 3. Furthermore, the surface of the substrate 2 is not limited to a plain color, and a background pattern may be formed on the surface of the substrate 2.

[0066] Furthermore, although the visible code 4 in the above embodiment is thermally printed on the heat-sensitive layer 20, the base material of the visible code 4 may be non-thermal paper, and the visible code 4 may be printed by an inkjet printer, a laser printer, etc. Furthermore, the visible code 4 may be printed in a color similar to black.

[0067] Furthermore, in the above embodiment, the visible code 4 is printed so as to overlap the entire infrared code 3, but it is sufficient that the visible code 4 overlaps the infrared code 3 to the extent that the infrared code 3 is difficult to read under visible light illumination.

[0068] In addition, the infrared light absorbing ink 22 forming the infrared code 3 and the heat sensitive layer 20 forming the visible code 4 may be covered with a coating layer that does not interfere with reading the infrared code 3 or the visible code 4.

[0069] In addition, one or both of the infrared code 3 and the visible code 4 may be formed as a two-dimensional code other than a QR code.

[0070] Furthermore, in the above embodiment, the presence or absence of the color of the infrared code 3 is confirmed based on a color image captured under illumination with white light, but the illumination light used during imaging can be changed within a range in which the white color of the surface of the substrate 2 and the color of the infrared code 3 can be distinguished. Furthermore, if the white color of the surface of the substrate 2 and the color of the infrared code 3 can be distinguished by differences in brightness, the captured image may be a monochrome image. Furthermore, in the above embodiment, the presence or absence of the color related to the infrared code 3 is determined based on the absolute value of the color value of the captured image, but the presence or absence of the color related to the infrared code 3 may also be determined based on the relative value of the color value of the captured image (color difference from the color of the substrate surface). [Explanation of symbols]

[0071] 1. Anti-counterfeit tickets (printed materials) 2 Base material 3 Infrared code (second 2D code) 4 Visible code (first two-dimensional code) 5. Text information 6. Two-dimensional code printing section 9 Ticket Management System 10 Information Management Server 11 Ticket machine 12 Ticket gates 13. Communication lines 14 Control computer 15 Gate opening and closing device 16 Ticket imaging device 18 Alarm device 19. Communications equipment 20 Heat sensitive layer 22 Infrared light absorbing ink 23,24 Position detection pattern

Claims

1. a first two-dimensional code that is printed in a dark color on the surface of a light-colored substrate and does not absorb infrared light in a predetermined band; a second two-dimensional code printed with infrared light absorbing ink that absorbs infrared light in the predetermined band; Equipped with the infrared light absorbing ink is a colored ink, the second two-dimensional code is printed so as to overlap the first two-dimensional code, A printed matter characterized in that the dark color of the first two-dimensional code is not printed, and the area where the infrared light absorbing ink is printed exhibits a predetermined light color that is easily distinguishable from the light color of the substrate surface.

2. 2. The printed matter according to claim 1, wherein the infrared absorbing ink is printed so that at least a specific portion of the first two-dimensional code exhibits the predetermined bright color.

3. 3. The printed matter according to claim 1, wherein the second two-dimensional code is printed so as to overlap almost entirely with the first two-dimensional code.

4. 3. The printed matter according to claim 1, wherein the size of each cell constituting the second two-dimensional code is equal to or larger than the size of each cell constituting the first two-dimensional code.

5. A ticket, 3. The printed matter according to claim 1, wherein the first two-dimensional code and the second two-dimensional code each contain information for verifying the validity of the ticket.

6. The method for verifying the validity of a printed matter according to claim 5, a first step of capturing an image including the first two-dimensional code and the second two-dimensional code under illumination with visible light; a second step of detecting the first two-dimensional code included in the image; a third step of determining whether the second two-dimensional code is printed so as to overlap the first two-dimensional code based on the color tone of the portion of the first two-dimensional code in the image that exhibits the predetermined bright color; A method for verifying the validity of a printed matter, comprising:

Images