JP5768596B2 - Page misalignment inspection system, printing system, printed matter, page misalignment inspection method - Google Patents

Description

The present invention relates to a page misalignment inspection system and the like for inspecting a page misalignment of printing on a medium on which a transparent ink is printed on a print such as color printing.

  In variable printing that differs depending on the page to be printed, if there is missing or duplicated printing, the printing order in which each page was printed does not correspond to the correct printing order in which each page should be printed. Will occur. In variable printing, it is important to avoid such page misalignment and to maintain consistency in the order of pages and the correspondence between front and back surfaces of pages. For this reason, various inspection techniques have been developed for inspecting page misalignment and ensuring consistency of page order and the like.

  As an example of page misalignment inspection in a medium that has been printed in color, for example, print permutation information of page numbers to be printed together with print data is acquired or set in advance, and the page numbers printed on the medium are displayed in the visible range. The image is taken by an imaging system composed of a wavelength illumination and a camera. Then, a page number is read from a photographed image by OCR (Optical Character Recognition) processing, and the read page number is compared with the page number to be printed to check the consistency of the page order and the like. (For example, refer to Patent Document 1).

By the way, as an example of variable printing, there is a case where printing with transparent ink is further performed on color printing or the like. The purpose of printing such a transparent ink includes security, desensitization by desensitizing ink, surface coating, and the like. In these cases, the printing position and content may be changed depending on the page.
For example, desensitizing ink is a pressure-sensitive copying sheet that transfers the content on the transfer sheet onto the receiving sheet using the pressure at the time of writing. However, the printing position of the desensitizing ink differs depending on the configuration of the entry column of the color printed page.

  Even in such a medium, it is desirable to inspect page misalignment in both printing such as color printing and transparent ink printing as described above. This is because when a page misalignment occurs, for example, there is a problem that the printing position of the transparent ink does not correspond to the printing position such as color printing.

JP 2005-251050 A

  When inspecting page misalignment in both printing such as color printing and transparent ink printing, for example, in order to visualize transparent ink under specific conditions, a fluorescent agent that is issued in the visible range by absorbing ultraviolet light is used. It is conceivable to mix with transparent ink. Then, a page number is printed on each medium during printing such as color printing and transparent ink printing.

  As for the page number printed in color or the like, the page number can be read from the photographed image obtained by photographing the page number in the same manner as described above to inspect the page deviation. On the other hand, the page number printed with transparent ink is photographed by an imaging system for transparent ink printing, which is composed of an ultraviolet wavelength illumination and a camera. From this photographed image data, as described above, the page number can be read by OCR processing, checked against the page number to be printed, and page misalignment can be inspected.

  However, the above method requires two types of imaging systems in which the illumination wavelength is changed for the page misalignment inspection, and there is a problem that the cost for the inspection increases.

  The present invention has been made in view of such problems, and its purpose is a page misalignment inspection system and the like that can inspect page misalignment of a medium on which transparent ink is printed on printing such as color printing with a simple apparatus configuration. Is to provide.

  A first invention for achieving the above-described object is a page misalignment inspection system for inspecting a page misalignment at the time of printing, which includes an image capturing device and an image processing device, and the image capturing device includes: The page identification symbol is printed, the second page identification symbol is printed with transparent ink that absorbs and emits ultraviolet light, and the transparent ink is printed at a position covering the first page identification symbol. The image processing device captures images of the first page identification symbol and the second page identification symbol captured by the imaging device. And a page misalignment inspection unit that detects page misalignment based on the captured image, and the page misalignment inspection unit includes the first page identification symbol and the Page identification symbol detection means for detecting two page identification symbols, and page deviation determination means for determining page deviation based on the detected first page identification symbol and the second page identification symbol. It is a page misalignment inspection system characterized by having.

With this configuration, the second page identification symbol by the transparent ink that absorbs and emits ultraviolet light appears as a bright region on an image photographed using illumination in the ultraviolet region.
On the other hand, the printed first page identification symbol emits light from the transparent ink printed on the first page identification symbol and reflects on the medium due to the difference in reflectance from the surrounding area on the medium. Thus, a difference in the amount of light incident on the peripheral area can be made. As a result, the first page identification symbol can be determined based on the luminance difference from the peripheral area on the image.
Therefore, it is possible to detect a page identification symbol by printing such as color printing and a page identification symbol by transparent ink printing based on a photographed image taken by one imaging system using ultraviolet wavelength illumination. It is possible to inspect page misalignment of printing such as printing and transparent ink printing.

The page identification symbol detection means performs an optical character recognition process on the photographed image obtained by inverting the brightness of the second page identification symbol and the surrounding area, thereby the first page identification symbol and the It is desirable to detect the second page identification symbol.
Thereby, it is possible to suitably inspect page misalignment from the captured image using an OCR (optical character recognition) processing technique.

The page misalignment determining means includes the first page identification symbol on the medium, printing permutation information indicating the printing order of the second page identification symbol, the detected first page identification symbol, the second page identification symbol, It is desirable to determine page misalignment by collating the page identification symbols.
Thereby, the detected page identification symbol can be collated with a positive page identification symbol, and a page misalignment inspection can be reliably performed.

  According to a second aspect of the invention, the first page identification symbol is printed on the medium, the second page identification symbol is printed with a transparent ink that absorbs ultraviolet rays and emits light, and the transparent ink is printed on the first page. A printing apparatus that prints at a position that covers the identification symbol; a photographing apparatus that photographs the medium in a state of being illuminated with ultraviolet light; and an image processing apparatus. The image processing apparatus is photographed by the photographing apparatus. A captured image acquisition unit that acquires captured images of the first page identification symbol and the second page identification symbol, and a page misalignment inspection unit that detects page misalignment based on the captured image, The page misalignment inspection unit includes a page identification symbol detection unit that detects the first page identification symbol and the second page identification symbol from the photographed image, and the detected first page identification. No. and based on the second page identification mark, is a printing system characterized by having, a page shift determining means for determining the page displacement.

The page identification symbol detection means performs an optical character recognition process on the photographed image obtained by inverting the brightness of the second page identification symbol and the surrounding area, thereby the first page identification symbol and the It is desirable to detect the second page identification symbol.
Further, the page misalignment determining means includes the first page identification symbol on the medium, print permutation information indicating the print order of the second page identification symbol, the detected first page identification symbol, It is desirable to determine page misalignment by collating the second page identification symbol.

  The second invention is a printing system in which a page misalignment inspection of a printed matter is suitably performed by the page misalignment inspection system of the first invention.

  According to a third aspect of the invention, a first page identification symbol is printed on a medium, a second page identification symbol is printed with a transparent ink that absorbs ultraviolet rays and emits light, and the transparent ink further includes the first page identification symbol. This is a printed matter printed at a position covering the page identification symbol.

  A third invention is a printed matter in which a page misalignment inspection is suitably performed by the page misalignment inspection system of the first invention.

  According to a fourth aspect of the invention, the photographing apparatus prints the first page identification symbol, prints the second page identification symbol with transparent ink that absorbs ultraviolet rays and emits light, and the transparent ink further includes the first page identification symbol. The step of photographing the medium printed at a position covering the page identification symbol is performed in a state where the medium is illuminated with ultraviolet rays, and the image processing apparatus captures the first page identification symbol and the first photographed by the photographing device. A captured image acquisition step of acquiring a captured image of the page identification symbol 2 and a page misalignment inspection step of detecting a page misalignment based on the captured image. In the page misalignment inspection step, Detecting the first page identification symbol and the second page identification symbol, and based on the detected first page identification symbol and the second page identification symbol. A page shift inspection method characterized by judging the page displacement.

When detecting the first page identification symbol and the second page identification symbol, an optical character recognition process is performed on the photographed image obtained by inverting the brightness of the second page identification symbol and its surrounding area. Is desirable.
Further, when determining page misalignment, the first page identification symbol on the medium, the print permutation information indicating the print order of the second page identification symbol, and the detected first page identification symbol, It is desirable to collate the second page identification symbol.

  The fourth invention relates to a page misalignment inspection method by the page misalignment inspection system of the first invention.

  According to the present invention, it is possible to provide a page misalignment inspection system and the like that can inspect page misalignment of a medium on which transparent ink is printed on printing such as color printing with a simple apparatus configuration.

The figure shown about the page shift inspection system 1 provided in the printing system 10 The figure which shows the page 5a of the printing paper 5 by which color printing and transparent ink printing were made | formed The figure which shows the hardware constitutions of the image processing apparatus 25 The figure which shows the function structure of the image processing apparatus 25. The figure which shows the printing permutation data 60 The flowchart which shows the flow of the whole process in the page gap inspection system 1. The figure explaining the picked-up image data 40 Flowchart showing the flow of page misalignment inspection in the page misalignment inspection system 1 The figure which shows the light-dark inverted image data 50 The figure which shows another example of the printing permutation data 60

  Hereinafter, embodiments of the page misalignment inspection system of the present invention will be described with reference to the drawings. First, with reference to FIG. 1, the outline of the page misalignment inspection system 1 of the present embodiment will be described. The page misalignment inspection system 1 of this embodiment is provided in the printing system 10 shown in FIG.

This printing system 10 stores print data and page number (page identification symbol) data corresponding to each print data for each of color printing and transparent ink printing in the print management server 11 along with the printing order. Accordingly, the printing device 12 performs variable printing for each page while conveying the roll-shaped printing paper 5 (medium). The printed paper 5 after printing is subjected to post-processing by a post-processing device such as a cutting machine (not shown) to obtain a target printed matter.
As described above, transparent ink printing is performed for the purpose of security, desensitization with desensitizing ink, surface coating, and the like.

As shown in FIG. 2, the printing apparatus 12 prints the color printing area 8 on each page 5a of the printing paper 5 during color printing, and at the predetermined position, the color ink page number 31 (first page identification symbol). When the transparent ink is printed, the transparent ink printing area 9 is printed and the transparent ink page number 32 (second page identification symbol) is printed at a predetermined position. In addition, the solid 33 is printed so as to cover the color ink page number 31 widely.
As the transparent ink, a known ink corresponding to the above-mentioned purpose is used, and a fluorescent agent that emits light by absorbing ultraviolet rays is blended. Known fluorescent agents can be used as appropriate. The transparent ink printing area 9, the transparent ink page number 32, and the solid 33 are invisible in a normal state.

  In the present embodiment, the printing paper 5 is substantially white, and color printing causes the color ink page number 31 to be a portion where the reflectance is lower than the background color of the printing paper 5. Further, reference numeral 5b in FIG. 2 denotes a cutting line, and the roll-shaped printing paper 5 is cut into a sheet by the cutting line 5b by the cutting machine.

  A page misalignment inspection system 1 shown in FIG. 1 inspects for the presence of page misalignment in the above-described color printing and transparent ink printing, and includes a PLC 21, an image processing device 25, a camera 27, a monitor 29, and the like.

  The PLC 21 receives a signal indicating the conveyance position of the page 5a of the printing paper 5 input from the sensor 23 disposed between the printing device 12 and the camera 27 in the conveyance direction of the printing paper 5 indicated by the arrow in FIG. Thus, a signal for controlling the camera 27 is sent to the image processing device 25 so that the color ink page number 31 and the transparent ink page number 32 of the page 5a are photographed at a predetermined timing when the page 5a comes to the position of the camera 27. Output.

The image processing device 25 controls the camera 27 based on the signal from the PLC 21 to photograph the color ink page number 31 and the transparent ink page number 32 of each page 5a of the printing paper 5, and obtain photographed image data.
Further, based on the photographed image data and the print permutation data indicating the print order of the color ink page number 31 and the transparent ink page number 32 acquired from the print management server 11 on each page 5a, color printing and transparency are performed by a method described later. The ink printing page deviation is inspected, and the inspection result is output to the monitor 29.

The camera 27 is a photographing device that photographs the color ink page number 31 and the transparent ink page number 32 of each page 5 a of the printing paper 5. The printing paper 5 is photographed in a state of being illuminated by an ultraviolet LED (Light Emitting Diode) illumination 26. The camera 27, the ultraviolet LED illumination 26, and the printing paper 5 photographed by the camera 27 are in the dark box 7 where the incident light is blocked.
The page misalignment inspection system 1 according to the present embodiment performs a page misalignment inspection on the printing paper 5 printed on one side, and images one side of the printing paper 5 facing the camera 27.

  The monitor 29 is a display device that displays a page misalignment inspection result input from the image processing device 25. It is also possible to input the photographic image data of the color ink page number 31 and the transparent ink page number 32 from the image processing device 25 and display them. In this case, the page is visually viewed from the photographic image displayed on the monitor 29. It is also possible to confirm the presence or absence of deviation.

  Next, the hardware configuration of the image processing apparatus 25 will be described with reference to FIG. As shown in FIG. 3, the image processing apparatus 25 is configured by connecting a control unit 201, a storage unit 202, a communication I / F unit 206, a peripheral device I / F unit 207, and the like via a bus 209.

The control unit 201 includes a CPU (Central Processing Unit), a ROM (Read Only Memory), a RAM (Random Access Memory), and the like.
The CPU calls a program stored in the storage unit 202, ROM, or the like to a work memory area on the RAM and executes it, and drives and controls each unit connected via the bus 209. The ROM permanently holds the control program, data, and the like for the image processing device 25. The RAM temporarily holds the loaded program and data, and includes a work area used by the control unit 201 to perform various processes described later.

  The storage unit 202 stores a program executed by the control unit 201, data necessary for program execution, and the like. These program codes are read as necessary by the control unit 201, transferred to the RAM, and read and executed by the CPU.

The communication I / F 206 is a communication interface having a communication control device, a communication port, and the like, and performs communication control that mediates communication with various devices.
A peripheral device I / F (interface) 207 is an interface for connecting the peripheral device to the image processing device 25, and the image processing device 25 transmits and receives data to and from the peripheral device via the peripheral device I / F 207.
The bus 209 is a path that mediates transmission / reception of control signals, data signals, and the like between the devices.

Next, the functional configuration of the image processing apparatus 25 will be described with reference to FIG.
As illustrated in FIG. 4, the image processing apparatus 25 includes a captured image acquisition unit 251, a page misalignment inspection unit 252, and an inspection result output unit 257, and stores captured image data 40 and print permutation data 60 in the storage unit 202. .

  In the photographed image acquisition unit 251, the control unit 201 of the image processing device 25 controls the camera 27 to photograph the color ink page number 31 and the transparent ink page number 32 of each page 5 a of the printing paper 5. Data 40 is acquired from the camera 27 and stored in the storage unit 202.

The page misalignment inspection unit 252 detects the page misalignment by the control unit 201 of the image processing device 25 based on the captured image data 40 and the print permutation data 60 acquired from the print management server 11. The unit 253, the page deviation determination unit 254, and the like.
As shown in FIG. 5, the print order data 60 indicates the print order on each page 5 a for each of the color ink page number 31 and the transparent ink page number 32.

  The page number detection means 253 detects the color ink page number 31 and the transparent ink page number 32 from the photographed image data 40.

  The page misalignment determining means 254 compares the detected color ink page number 31 and transparent ink page number 32 with the page number of the print permutation data 60 to determine page misalignment.

  The inspection result output unit 257 is for the control unit 201 of the image processing apparatus 25 to output the page misalignment inspection result to the monitor 29 or the like.

Next, a page misalignment inspection processing procedure in the page misalignment inspection system 1 will be described with reference to FIGS.
First, the overall processing procedure of the page misalignment inspection system 1 will be described with reference to FIG.

In the page misalignment inspection system 1, first, the color ink page number 31 and the transparent ink page number 32 for the page 5 a of the printing paper 5 on which the color printing and the transparent ink printing have been performed as described with reference to FIG. Is captured by the camera 27, and the captured image data 40 is acquired (S101). At the time of shooting, the printing paper 5 is irradiated with light having an ultraviolet wavelength by the ultraviolet LED illumination 26.
As described above, since the position of the page 5a of the printing paper 5 before being conveyed to the position of the camera 27 is detected by the sensor 23, this detection signal input to the PLC 21 by the sensor 23 is used as a trigger from the PLC 21. By outputting a control signal to the image processing device 25 at a predetermined timing, the color ink page number 31 and the transparent ink page number 32 of the page 5a can be photographed when it is conveyed to the position of the camera 27.

  Next, the control unit 201 of the image processing apparatus 25 performs a page misalignment inspection based on the captured image data 40 acquired in S101 and the print permutation data 60 acquired in advance from the print management server 11 (step S102). This procedure will be described later.

  The inspection result is output from the image processing device 25 to the monitor 29 and displayed on the monitor 29 (S103). Thereby, the operator can confirm the inspection result.

  Next, the page misalignment inspection in S102 will be described.

  Here, the photographed image data 40 will be described with reference to FIG. 7 before explaining the page misalignment inspection.

At the time of photographing by the camera 27, as shown in FIG. 7A, in the transparent ink page number 32, the transparent ink 321 emits visible light by absorption of ultraviolet rays, and the emitted light 322 and the emitted light are emitted on the printing paper 5. The reflected light 323 reflected by the light enters the lens of the camera 27.
Therefore, as shown in FIG. 7C, on the photographed image data 40, the transparent ink page number 32 is a bright region having a higher luminance (high pixel value) than the peripheral region where the transparent ink 321 does not exist.

On the other hand, the color ink page number 31 is a portion where the reflectance decreases on the printing paper 5 as described above. As shown in FIG. 7B, the emitted light 322 and the reflected light 323 from the transparent ink 321 printed as a solid 33 on the color ink page number 31 are incident on the lens of the camera 27. The amount of reflected light 323a that reflects the 31 color ink 324 is lower than the amount of reflected light 323b that reflects on the printing paper 5 in the peripheral region.
Therefore, as shown in FIG. 7C, the color ink page number 31 appears as a dark area with lower luminance (lower pixel value) than the surrounding area on the captured image data 40.

FIG. 8 shows a flow of page misalignment inspection in the image processing apparatus 25.
When the page misalignment inspection is performed, first, the control unit 201 of the image processing device 25 has a pixel value equal to or greater than a threshold value for the acquired image data 40 as described above with respect to the transparent ink page number 32 and its peripheral region. By performing processing such as binarization, in which the area of the image is a dark area and the area below the threshold is a light area, the light / dark inverted image data 50 obtained by inverting the light / dark of the transparent ink page number 32 and its surrounding area is acquired. (S201).
An example of the bright / dark inverted image data 50 is shown in FIG. As a result of the light / dark reversal processing, the transparent ink page number 32 appears as a dark region having a lower luminance than the peripheral region on the light / dark reversal image data 50, as with the color ink page number 31.

  Next, the image processing device 25 performs known OCR processing on the light / dark inverted image data 50 to read and detect the color ink page number 31 and the transparent ink page number 32 (step S202).

Then, the image processing device 25 detects the color ink page number 31 and the transparent ink page number 32 to be printed on the page 5a of the printing paper 5 based on the print permutation data 60 acquired from the print management server 11 in advance. The color ink page number 31 and the transparent ink page number 32 are compared and collated to determine whether or not there is a page shift (step S203).
For example, when “124” is detected after “122” is detected for the transparent ink page number 32, “123” is not “123” after “122” from the collation with the print permutation data 60 shown in FIG. It is determined that page misalignment has occurred.

  As described above, the page misalignment inspection in S102 is performed. In the present embodiment, the color ink page number 31 on the printing paper 5 is a portion where the reflectance is lower than the surroundings, but the reverse may be possible. That is, even when the color ink page number 31 has a higher reflectance than the surrounding area, the page number can be detected by the same procedure. In this case, the color ink page number 31 appears on the captured image data 40 as a bright area having a higher luminance than the peripheral area, so that the above-described bright / dark reversal can be omitted and the process can proceed to OCR processing.

  As described above, in the present embodiment, color images and transparent ink printing are not used, but based on a photographed image photographed by one imaging system using ultraviolet wavelength illumination, color images are used. Since the page number by printing and transparent ink printing can be detected, it is possible to inspect page misalignment between color printing and transparent ink printing with a simple apparatus configuration.

Further, by performing OCR processing on the transparent ink page number 32 of the photographed image data 40 and the light / dark inverted image data 50 obtained by reversing the brightness of the surrounding area, the color ink page number 31 and the transparent ink page number 32 are obtained. Therefore, the page misalignment can be suitably inspected from the captured image data 40 using the OCR processing technique.
In addition, the print permutation data 60 indicating the print order of the color ink page number 31 and the transparent ink page number 32 on each page 5a of the printing paper 5 is compared with the detected color ink page number 31 and the transparent ink page number 32. Therefore, the detected page number is collated with the positive page number, and the page misalignment can be reliably checked.

  Further, in the present embodiment, the detection of page misalignment when single-sided printing is performed has been described. However, as a modification of the present embodiment, when printing on the front and back surfaces of the printing paper 5, the page misalignment is similarly inspected. Can do. In this case, a camera 27 and an ultraviolet LED illumination 26 for photographing the front and back surfaces of the printing paper 5 are provided, and on the front and back surfaces, the printed color ink page number 31 and the transparent ink page are the same as described above. Take number 32. Then, the color ink page number 31 and the transparent ink page number 32 are detected from the photographed image data 40.

  As shown in FIG. 10, the printing sequence data 60 indicates the printing order of the color ink page number 31 and the transparent ink page number 32 for each of the front and back surfaces, and the detected color ink page number 31 and the transparent ink page number 32. It is possible to determine whether or not there is a page shift by comparing this with the above. For example, when “122” is detected after detecting “121” as the color ink page number 31 on the surface of the printing paper 5, after the comparison with the print permutation data 60 shown in FIG. Instead of “123”, it is determined that a page shift has occurred.

  Further, the method for determining the page shift based on the detected page number is not limited to this. For example, the read color ink page number 31 and the transparent ink page number 32 may be compared, and whether or not there is a page shift may be determined based on whether or not they match. In this case, it is not always necessary to acquire the print permutation data 60 from the print management server 11.

In this embodiment, the page number is used for the page misalignment inspection process. However, the page number may be replaced with another symbol that can identify each page 5a of the printing paper 5, and a preset character or the like is used. Is also possible.
Furthermore, in this embodiment, the transparent ink 321 is printed as the solid 33 on the color ink page number 31, but the present invention is not limited to this, and halftone printing may be performed.
In addition, the page misalignment inspection according to the present embodiment can be similarly applied to monochrome printing instead of color printing.

In addition, an alarm device such as a lamp may be connected to the PLC 21, and an alarm device may issue an alarm when a page shift occurs. That is, when a page shift is detected by the image processing device 25, a signal indicating this is output to the PLC 21, and the PLC 21 receives this signal and outputs a control signal to the alarm device so as to give an alarm such as lighting of the lamp. Keep it. As a result, the operator can be alerted that a page shift has occurred. In addition to the lamp, the alarm device may emit an alarm by sound.
Further, an information processing device such as a general-purpose computer may be connected to the PLC 21 to perform tabulation of page misalignment inspection results. That is, the inspection result is output from the image processing device 25 to the PLC 21, and the inspection result is output from the PLC 21 to the computer. As a result, the page misalignment inspection results can be aggregated by the computer, and management data such as the page misalignment occurrence rate can be calculated.

  The preferred embodiments of the present invention have been described above with reference to the accompanying drawings, but the present invention is not limited to such examples. It will be apparent to those skilled in the art that various changes or modifications can be conceived within the scope of the technical idea disclosed in the present application, and these naturally belong to the technical scope of the present invention. Understood.

1 ... …… Page misalignment inspection system 5 ……… Printing paper 7 ……… Dark box 10 ……… Print system 11 ……… Print management server 12 ……… Printing device 21 ……… PLC
25 ……… Image processing device 26 ……… Ultraviolet LED illumination 27 ……… Camera 29 ……… Monitor 31 ……… Color ink page number 32 ……… Transparent ink page number 33 ……… Solid 40 ……… Photographing Image data 60... Print permutation data 251... Captured image acquisition section 252... Page misalignment inspection section 253... Page number detection means 254.

Claims (10)

A page misalignment inspection system for inspecting a page misalignment at the time of printing, including a photographing device and an image processing device,
In the photographing apparatus, a first page identification symbol is printed, a second page identification symbol is printed with transparent ink that absorbs ultraviolet rays and emits light, and the transparent ink further displays the first page identification symbol. Take a picture of the medium printed on the cover, illuminated by ultraviolet rays,
The image processing apparatus includes:
A captured image acquisition unit that acquires captured images of the first page identification symbol and the second page identification symbol captured by the imaging device;
A page deviation inspection unit for detecting page deviation based on the captured image,
The page misalignment inspection unit
Page identification symbol detection means for detecting the first page identification symbol and the second page identification symbol from the captured image;
A page misalignment inspection system comprising: a page misalignment determination unit that determines a page misalignment based on the detected first page identification symbol and the second page identification symbol.   The page identification symbol detection means performs an optical character recognition process on the photographed image obtained by inverting the brightness of the second page identification symbol and the surrounding area, thereby the first page identification symbol and the The page misalignment inspection system according to claim 1, wherein a second page identification symbol is detected.   The page misalignment determining means includes the first page identification symbol on the medium, printing permutation information indicating the printing order of the second page identification symbol, the detected first page identification symbol, the second page identification symbol, The page misalignment inspection system according to claim 1, wherein the page misalignment is determined by collating the page identification symbols. A first page identification symbol is printed on the medium, a second page identification symbol is printed with transparent ink that absorbs ultraviolet rays and emits light, and the transparent ink is placed at a position covering the first page identification symbol. A printing device for printing;
A photographing device for photographing the medium while being illuminated with ultraviolet rays;
An image processing device,
The image processing apparatus includes:
A captured image acquisition unit that acquires captured images of the first page identification symbol and the second page identification symbol captured by the imaging device;
A page deviation inspection unit for detecting page deviation based on the captured image,
The page misalignment inspection unit
Page identification symbol detection means for detecting the first page identification symbol and the second page identification symbol from the captured image;
A printing system comprising: a page deviation determination unit configured to determine a page deviation based on the detected first page identification symbol and the second page identification symbol.   The page identification symbol detection means performs an optical character recognition process on the photographed image obtained by inverting the brightness of the second page identification symbol and the surrounding area, thereby the first page identification symbol and the The printing system according to claim 4, wherein a second page identification symbol is detected.   The page misalignment determining means includes the first page identification symbol on the medium, printing permutation information indicating the printing order of the second page identification symbol, the detected first page identification symbol, the second page identification symbol, The printing system according to claim 4, wherein the page deviation is determined by collating the page identification symbols.   The first page identification symbol is printed on the medium, the second page identification symbol is printed with transparent ink that absorbs and emits ultraviolet light, and the transparent ink covers the first page identification symbol. Printed material printed on. The photographing apparatus prints the first page identification symbol, prints the second page identification symbol with transparent ink that absorbs ultraviolet rays and emits light, and the transparent ink covers the first page identification symbol. Performing a step of photographing the medium printed at the position illuminated by ultraviolet rays;
The image processing device
A captured image acquisition step of acquiring captured images of the first page identification symbol and the second page identification symbol captured by the imaging device;
A page misalignment inspection step for detecting page misalignment based on the captured image; and
In the page misalignment inspection step,
Detecting the first page identification symbol and the second page identification symbol from the captured image;
A page misalignment inspection method, wherein page misalignment is determined based on the detected first page identification symbol and the second page identification symbol.   When detecting the first page identification symbol and the second page identification symbol, an optical character recognition process is performed on the photographed image obtained by inverting the brightness of the second page identification symbol and its surrounding area. The page misalignment inspection method according to claim 8.   When determining page misalignment, the first page identification symbol on the medium, the print permutation information indicating the print order of the second page identification symbol, the detected first page identification symbol, the first page identification symbol, 10. The page misalignment inspection method according to claim 8, wherein two page identification symbols are collated.

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