Overprint inspection apparatus, overprint inspection method, and computer readable medium

Abstract

The present application provides a kind of overprint inspection device, overprint inspection method and computer readable medium, can reduce the data quantity of comparison processing object. Overprint inspection device includes processor, and the processor detects the defect of overprint processing by the comparison of subsequent image and subsequent printing data, the subsequent image is detected from the overprinted printing medium formed by using the overprint processing, the overprint processing is to the overprinted printing medium printed with the preceding image based on preceding printing data, and the subsequent image based on the subsequent printing data is printed.

Description

Technical Field

[0001] This disclosure relates to a print inspection apparatus, a print inspection method, and a computer-readable medium. Background Technology

[0002] Previously, printing media with printed images underwent further processing of the printed image. This printing processing was called "post-printing processing." In this specification, the printing media with the image printed on it but before post-printing processing is referred to as the "pre-post-printing printing media," the image printed on the pre-post-printing printing media is referred to as the "prior image," and the printing media after post-printing processing is referred to as the "post-post-printing printing media." Furthermore, the image printed on the post-post-printing printing media is referred to as the "post-post-printing image." If post-printing processing is performed appropriately, the post-post-printing image becomes an image formed by combining the prior image and the subsequent image.

[0003] On the other hand, conventionally, after printing data onto a printing medium, the printing data is compared with an image obtained by optically reading the printed medium (i.e., the image printed on the printing medium) to detect defects in the printing process. For example, if the consistency between the printing data and the image is above a predetermined threshold, the printing process can be determined to be "good"; if the consistency is below the threshold, the printing process can be determined to be "defective". Defects in the printing process include, for example, problems in the process of converting the printing data to a raster format (data corruption) and problems in the process of printing the printing data onto the printing medium (skimming, smudges, etc.).

[0004] Here, as Figure 12 As shown, consider the following situation: in the preliminary image forming apparatus, a preliminary image is printed based on preliminary printing data; in the subsequent image forming apparatus, a follow-up printing process is performed to print a subsequent image based on subsequent printing data on the pre-printing printing medium; and in the follow-up printing inspection apparatus, defects in the follow-up printing process are detected.

[0005] In the follow-up printing process in the subsequent image forming apparatus, the subsequent printing data represents the subsequent image ( Figure 12 The example shows an image of a batter. Subsequent printing data is used, and on the reprinted printing medium, not only is the subsequent image printed, but also the preceding image (…). Figure 12 (The example uses the number "1"). That is, even if the reprinting process is performed accurately, the subsequent printing data will differ from the reprinted image.

[0006] Therefore, if the reprint inspection device simply compares the subsequent printing data with the reprinted image, it cannot properly detect defects in the reprint process.

[0007] In view of this, Japanese Patent Application Publication No. 2011-70548 discloses an image inspection device that generates an image of the pre-printed elements printed on the pre-printed paper with reduced quality based on an image of the pre-printed paper obtained by photographing the pre-printed paper as a pre-printing medium and an image of the post-printed medium obtained by photographing the post-printed medium. The device then compares the generated image of the inspection object with additional recorded data as subsequent printing data to detect defects in the reprinting process. Summary of the Invention

[0008] Furthermore, taking the method disclosed in the aforementioned patent publication as an example, when detecting defects in the reprinting process by comparing printing data with an image printed on a printing medium, a comparison is considered using three types of data: prior printing data, subsequent printing data, and the reprinted image. For example, a comparison is considered between combined data obtained by combining prior and subsequent printing data and the reprinted image. Moreover, a comparison is considered between image data obtained by subtracting prior printing data from the reprinted image and subsequent printing data. Alternatively, a comparison is considered between image data obtained by subtracting subsequent printing data from the reprinted image and prior printing data.

[0009] However, when comparing prior print data, subsequent print data, and reprinted images, the amount of data to be compared may increase compared to comparing subsequent images with subsequent print data. If the amount of data to be compared increases, problems such as increased processing load may arise.

[0010] The purpose of this disclosure is to reduce the amount of data in the comparison processing object when detecting defects in the follow-up processing of printing a subsequent image based on subsequent printing data on a printing medium where a preceding image based on preceding printing data has been printed, by comparing printing data with an image printed on a printing medium, compared to the case of comparing preceding printing data, subsequent printing data, and an image printed on a printing medium where the follow-up processing has been completed.

[0011] According to a first aspect of this disclosure, a follow-up printing inspection apparatus is provided, comprising a processor that detects defects in the follow-up printing process by comparing a subsequent image with subsequent printing data. The subsequent image is detected from a post-follow-up printing medium formed using the follow-up printing process. The follow-up printing process is the printing of the subsequent image based on the subsequent printing data onto a pre-follow-up printing medium having a prior image based on prior printing data.

[0012] According to a second aspect of this disclosure, in the reprinting process, the subsequent image is printed using a specific color not used in the preceding image, the subsequent image being detected from the reprinted printing medium by a sensor that detects the specific color.

[0013] According to a third aspect of this disclosure, the subsequent image is an image detected from a specific region determined based on the subsequent printing data, the specific region being the area in the post-printing medium where the subsequent image is printed.

[0014] According to the fourth aspect of this disclosure, when the preceding image and the subsequent image overlap in the post-printing medium, the processor detects defects in the post-printing process by comparing the preceding printing data, the subsequent printing data, and the image printed on the post-printing medium.

[0015] According to the fifth aspect of this disclosure, the processor uses image data acquired by optically reading the pre-printing medium as the preliminary printing data.

[0016] According to the sixth aspect of this disclosure, for the multi-page pre-printing medium, a multi-page post-printing medium is formed by a post-printing process based on the subsequent printing data of the multi-page. In pages where the preceding image and the subsequent image do not overlap, the processor detects defects in the post-printing process by comparing the subsequent image detected from the page with the subsequent printing data. In pages where the preceding image and the subsequent image overlap, the processor detects defects in the post-printing process by comparing the preceding image, the subsequent image, and the image printed on the post-printing medium.

[0017] According to a seventh aspect of this disclosure, a computer-readable medium is provided, storing a program that causes a computer to perform processing, wherein the processing detects defects in a follow-up printing process by comparing a subsequent image with subsequent printing data, the subsequent image being detected from a post-follow-up printing medium formed using the follow-up printing process, the follow-up printing process being the printing of the subsequent image based on the subsequent printing data onto a pre-follow-up printing medium having a prior image based on prior printing data.

[0018] According to the eighth aspect of this disclosure, a method for checking follow-up printing is provided, which detects defects in follow-up printing by comparing a subsequent image with subsequent printing data. The subsequent image is detected from a post-follow-up printing medium formed using the follow-up printing process. The follow-up printing process is to print the subsequent image based on the subsequent printing data on a pre-follow-up printing medium that has a prior image based on prior printing data.

[0019] (Effect)

[0020] According to the first, seventh, or eighth scheme, when detecting defects in the follow-up printing process of printing a subsequent image based on subsequent printing data on a printing medium where a preceding image based on preceding printing data has been printed, by comparing printing data with an image printed on the printing medium, the amount of data in the comparison processing object can be reduced compared to the case of comparing preceding printing data, subsequent printing data, and an image printed on the printing medium after the follow-up printing process.

[0021] According to the second scheme, subsequent images can be detected from the reprinted printing medium by using a sensor that detects specific colors.

[0022] According to the third scheme, subsequent images can be detected from specific areas of the reprinted printing medium.

[0023] According to the fourth scheme, when the preceding image and the subsequent image overlap in the reprinted printing medium, defects in the reprinting process can be detected by comparing the preceding printing data, the subsequent printing data, and the image printed on the reprinted printing medium.

[0024] According to the fifth scheme, a preliminary image can be acquired by a pre-printing medium reading unit.

[0025] According to the sixth scheme, in pages where the preceding image and the subsequent image do not overlap, defects in the follow-up printing process can be detected by comparing the subsequent image with the subsequent printing data. In pages where the preceding image and the subsequent image overlap, defects in the follow-up printing process can be detected by comparing the preceding image, the subsequent image, and the image printed on the follow-up printing medium. Attached Figure Description

[0026] Figure 1 This is a schematic diagram of the traceability system of this embodiment.

[0027] Figure 2 This is a schematic diagram of the printing control device according to this embodiment.

[0028] Figure 3A This is a diagram illustrating an example of the content of pre-printed data.

[0029] Figure 3B This is a diagram showing an example of a printing medium before reprinting.

[0030] Figure 4A This is a diagram illustrating an example of the content of subsequent printed data.

[0031] Figure 4B This is a diagram showing an example of a printing medium after reprinting.

[0032] Figure 5 It is a conceptual diagram representing a specific area where subsequent images will be printed.

[0033] Figure 6 This is a schematic diagram of the structure of the print inspection device according to this embodiment.

[0034] Figure 7 It is a diagram representing a subsequent image detected from the reprinted printed medium.

[0035] Figure 8 This is another example of a diagram representing the content of subsequent printing data.

[0036] Figure 9 This is a diagram showing another example of a printing medium after reprinting.

[0037] Figure 10 This is a flowchart illustrating the processing flow of the printing control device in this embodiment.

[0038] Figure 11 This is a flowchart illustrating the processing flow of the print inspection device in this embodiment.

[0039] Figure 12 This diagram illustrates the previous reprint process. Detailed Implementation

[0040] Figure 1 This is a schematic diagram of the structure of the tracking system 10 according to this embodiment. The tracking system 10 is a system that performs tracking processing and detects defects in the tracking process. The tracking system 10 is not limited to this; for example, it can be installed in a printing company that performs production printing processes. Figure 1 As shown, the tracking system 10 comprises a printing control device 12, a preliminary image forming device 14, a subsequent image forming device 16, and a tracking inspection device 18. The printing control device 12 is communicatively connected to the preliminary image forming device 14, the printing control device 12 is communicatively connected to the subsequent image forming device 16, and the printing control device 12 is communicatively connected to the tracking inspection device 18.

[0041] The printing control device 12 is a device that controls the preceding image forming apparatus 14, the subsequent image forming apparatus 16, and the follow-up inspection device 18. In other words, the printing control device 12 is a device that controls the follow-up processing and the detection and processing of defects in the follow-up processing. Furthermore, the printing control device 12 also functions as an interface with the user of the follow-up system 10. For details regarding the printing control device 12, please refer to... Figure 2 We'll discuss that later.

[0042] Both the preliminary image forming apparatus 14 and the subsequent image forming apparatus 16 are printers. Specifically, the preliminary image forming apparatus 14 and the subsequent image forming apparatus 16 are respectively configured to include a receiving unit that receives a printing request (i.e., a printing job) from the printing control device 12, a conveying unit that conveys printing media such as paper, a conversion unit that converts non-raster format printing data contained in the printing job into raster format (a format that the printing unit can recognize, as described later), and a printing unit that prints an image corresponding to the printing data on the printing media.

[0043] Here, the follow-up printing process in the follow-up printing system 10 will be described. First, the printing control device 12 sends a preliminary printing job containing preliminary printing data representing a preliminary image to the preliminary image forming device 14, and a follow-up printing job containing follow-up printing data representing a follow-up image to the follow-up image forming device 16. The preliminary image forming device 14 prints a preliminary image onto the printing medium based on the preliminary printing job. The printing medium with the preliminary image printed on it is the pre-follow-up printing medium 20. The pre-follow-up printing medium 20 is transported to the follow-up image forming device 16 by the user or by the transport unit of the preliminary image forming device 14. Next, the follow-up image forming device 16 prints a follow-up image onto the pre-follow-up printing medium 20 based on the follow-up printing job. That is, the follow-up image forming device 16 performs the follow-up printing process. The printing medium with both the preliminary image and the follow-up image printed on it is the post-follow-up printing medium 22. The post-follow-up printing medium 22 is transported to the follow-up inspection device 18 by the user or by the transport unit of the follow-up image forming device 16.

[0044] The reprint inspection device 18 detects defects in the reprinting process performed by the subsequent image forming apparatus 16. Details of the structure of the reprint inspection device 18 and the defect detection process performed by the reprint inspection device 18 will be described later. Alternatively, the reprint inspection device 18 can also detect defects in the printing process performed by the preliminary image forming apparatus 14 before detecting defects in the reprinting process. Specifically, the reprint inspection device 18 can also detect defects in the printing process performed by the preliminary image forming apparatus 14 by comparing preliminary printing data with a preliminary image obtained by optically reading the pre-reprinting printing medium 20 (e.g., scanning by a scanner or imaging by a camera).

[0045] Figure 2This is a schematic diagram of the printing control device 12. The printing control device 12 can be any device as long as it performs the functions described below. For example, the printing control device 12 can be a computer attached to the preceding image forming apparatus 14, the subsequent image forming apparatus 16, and the overprint inspection apparatus 18. Alternatively, the printing control device 12 can also be, for example, a server computer capable of communicating with the preceding image forming apparatus 14, the subsequent image forming apparatus 16, the overprint inspection apparatus 18, and the user terminal used by the user.

[0046] The communication interface 30 may include, for example, a network adapter or a dedicated adapter for connecting the printing control device 12 to other devices (the preliminary image forming apparatus 14, the subsequent image forming apparatus 16, and the overprint inspection device 18). The communication interface 30 functions to communicate with other devices. For example, the communication interface 30 receives printing jobs from the user terminal used by the user of the overprint system 10. Furthermore, the communication interface 30 sends printing data to the preliminary image forming apparatus 14 and the subsequent image forming apparatus 16. Moreover, the communication interface 30 sends inspection instruction information related to the overprint processing inspection to the overprint inspection device 18 (details described later). Finally, the communication interface 30 receives the overprint processing inspection results from the overprint inspection device 18.

[0047] The input interface 32 may include, for example, buttons or a touch panel. The input interface 32 is used to input instructions from the user of the tracking system 10 to the printing control device 12.

[0048] The display 34 may include, for example, a liquid crystal display. Various information related to the tracking system 10 is displayed on the display 34. For example, the inspection results of the tracking process performed by the tracking inspection device 18 are displayed on the display 34.

[0049] The memory 36 may include, for example, a hard disk drive (HDD), a solid-state drive (SSD), read-only memory (ROM), or random access memory (RAM). The memory 36 may be provided independently of the processor 38 (described later), or at least partially within the processor 38. The memory 36 stores printing control programs for operating the various parts of the printing control device 12. Furthermore, the memory 36 temporarily holds printing jobs input by the user.

[0050] The printing operation in this embodiment includes printing data representing an image of the object to be printed. As described above, the data format of the printing data included in the printing operation sent by the printing control device 12 is a non-raster format that cannot be recognized by the preliminary image forming apparatus 14 and the subsequent image forming apparatus 16. After the printing data is converted into a raster format by the preliminary image forming apparatus 14 or the subsequent image forming apparatus 16, the image corresponding to the printing data is printed onto the printing medium. As a printing operation, there is a preliminary printing operation for the preliminary image forming apparatus 14 and a subsequent printing operation for the subsequent image forming apparatus 16. The preliminary printing operation includes preliminary printing data representing a preliminary image, and the subsequent printing operation includes subsequent printing data representing a subsequent image. Examples of the content of the preliminary printing data, although not limited to this, include, for example, borders or grid lines. Examples of the content of the subsequent printing data, although not limited to this, include, for example, text or numbers within or along the border lines. Moreover, sometimes the content of the preliminary printing data is set to an image of a first color, and the content of the subsequent printing data is set to an image of a second color different from the first color, that is, the preliminary image and the subsequent image are printed in different colors. In addition, in this specification, without making a special distinction between prior printing data and subsequent printing data, they are collectively referred to as "printing data".

[0051] Processor 38 refers to a processor in a broad sense, comprising at least one general-purpose processing device (such as a central processing unit (CPU)) or a special-purpose processing device (such as a graphics processing unit (GPU), application-specific integrated circuit (ASIC), field-programmable gate array (FPGA), or programmable logic device). Processor 38 may also not consist of a single processing device, but rather be configured through the cooperation of multiple processing devices located in physically separate locations. Figure 2 As shown, the processor 38 functions as a printing instruction unit 40, an inspection instruction unit 42, an overlap determination unit 44, and a data binding unit 46 through the printing control program stored in the memory 36.

[0052] The printing instruction unit 40 sends printing jobs containing printing data to the preliminary image forming apparatus 14 and the subsequent image forming apparatus 16. Specifically, the printing instruction unit 40 sends a preliminary job containing preliminary printing data representing a preliminary image to the preliminary image forming apparatus 14, and a subsequent job containing subsequent printing data representing a subsequent image to the subsequent image forming apparatus 16.

[0053] Figure 3A This is a diagram illustrating an example of the content of pre-printed data. Figure 3A In the example, the advance print job is an instruction to print six pages of printing media, and the advance print data represents six pages of advance images. Figure 3A In the example, the content of the preliminary print data includes the text "1" to "6" printed on pages one through six respectively. The content of the preliminary print data may not represent a multi-page preliminary image, but may represent a single-page preliminary image.

[0054] Figure 3B It means based on inclusion Figure 3A The example shown is a pre-printing operation of the pre-printed data, where the pre-printed image is printed on a pre-printing medium 20 containing the pre-printed image by the pre-printing image forming apparatus 14. In this example, the pre-printed data represents six pages of pre-printed images, therefore the pre-printing medium 20 also contains six pages, with the text "1" to "6" as pre-printed images printed on the first to sixth pages respectively. Of course, if the content of the pre-printed data represents a single page of pre-printed images, the pre-printing medium 20 is also a single page.

[0055] In this example, we assume the preliminary image is printed in black. Specifically, this can be done either by specifying black and white printing in the printing settings of the preliminary print job, or by ensuring that the preliminary image itself, as represented by the preliminary print data, is black.

[0056] Compare Figure 3A and Figure 3B It is known that if the preliminary image forming apparatus 14 accurately performs the printing process based on the preliminary printing operation, the content of the preliminary printing data (the image represented by the preliminary printing data) is consistent with the preliminary image printed on the pre-printing medium 20.

[0057] Figure 4A This is an example diagram illustrating the content of subsequent print data. As mentioned above, in this example, the preceding print job is an instruction to print six pages, and correspondingly, the subsequent print job is also an instruction to print six pages. Therefore, the subsequent print data represents six pages of subsequent images. If the preceding print job is an instruction to print a single page, then the subsequent print job could also instruct the printing of a single page.

[0058] Figure 4A In the example, subsequent print data includes images of batters printed in the upper right corner of the first, third, and fifth pages. No images are included on the second, fourth, and sixth pages. That is, Figure 4A In the example, subsequent printing data indicates that the batter's image is printed only on the first, third, and fifth pages, and that nothing is printed on the second, fourth, and sixth pages.

[0059] Figure 4B It means based on inclusion Figure 4A The subsequent printing operation of the subsequent printing data shown is performed by the follow-up printing process of the subsequent image forming apparatus 16. Figure 3B The diagram shows a post-printing medium 22 printed with subsequent images on a pre-printing medium 20. (See diagram for reference.) Figure 4B As shown, in the reprinted printing medium 22, on the first, third, and fifth pages, the text "1", "3", or "5" as the preceding image and the image of the batter as the subsequent image are printed as reprinted images. On the second, fourth, and sixth pages, the text "2", "4", or "6" as the preceding image are printed as reprinted images.

[0060] In this embodiment, it is assumed that in the follow-up printing process, the subsequent image is printed using a color not used in the preceding image (referred to as a "specific color" in this specification). Specifically, color printing is specified in the printing settings of the subsequent printing job, and the color of the subsequent image itself, as represented by the subsequent printing data, is the specific color. In this example, as described above, the preceding image is printed in black, therefore the subsequent image is printed in a color other than black. For example, it is assumed that the subsequent image is printed in red. Moreover, the specific color can also be multiple colors. For example, if the preceding image is printed in black, the subsequent image can also be printed in multiple specific colors other than black (e.g., red, blue, yellow, etc.).

[0061] Furthermore, when the preliminary image is printed using multiple colors, the subsequent image is printed in a specific color other than those used in the preliminary image. For example, if the preliminary image is printed in black and red, the subsequent image is printed in blue, which is the specific color. Moreover, as in this example, when the reprinted printing medium 22 contains multiple pages, the subsequent images on each page do not necessarily have to be printed in the same color, as long as they are specific colors. For example, if the preliminary image is printed in black, the subsequent image on the first page can be printed in red, the subsequent image on the third page in blue, and the subsequent image on the fifth page in yellow. In this case, the colors of the subsequent images on each page can also be multiple specific colors.

[0062] Compare Figure 4A and Figure 4B It is known that, after printing on the reprinting medium 22 (which has both prior and subsequent images printed on it), Figure 4B Even if the subsequent image forming apparatus 16 accurately performs the printing process based on the subsequent printing operation in the first, third and fifth pages of the paper, the content of the subsequent printing data (the image represented by the subsequent printing data) is not consistent with the image printed on the post-printing medium 22.

[0063] return Figure 2 The inspection instruction unit 42 sends the inspection information required for the reprint processing, namely the inspection information and the inspection instruction for the reprint processing, to the reprint inspection device 18, thereby causing the reprint inspection device 18 to perform the reprint inspection.

[0064] In this embodiment, the inspection instruction unit 42 sends specific color information, representing a specific color for printing subsequent images, to the print inspection device 18 as inspection information. The inspection instruction unit 42 can determine the specific color by analyzing subsequent printing data. Alternatively, if a user inputs a specific color through the input interface 32, the inspection instruction unit 42 can determine the specific color based on the user input.

[0065] When subsequent images are printed in multiple colors, the specific color information represents multiple specific colors. Furthermore, when the reprinted printing medium 22 contains multiple pages and the subsequent images of each page are different specific colors, the inspection instruction unit 42 sends information that associates the page number of the reprinted printing medium 22 with the specific color used in the printing of the subsequent image of the page as specific color information to the reprint inspection device 18.

[0066] Furthermore, the inspection instruction unit 42 may replace the specific color information, or in addition to the specific color information, send specific area information, which represents the area in the printed medium 22 where subsequent images will be printed, as inspection information to the print inspection device 18. The inspection instruction unit 42 can determine the specific area by analyzing subsequent printing data.

[0067] Figure 5 This is a conceptual diagram representing a specific area 50. Subsequent printing data contains information not only representing the shape or color of the subsequent image, but also indicating the printing position of the subsequent image on the reprinted printing medium 22. For example, if the subsequent printing data is... Figure 4A As shown above, the subsequent printing data indicates that subsequent images will be printed in the upper right corner area of ​​the first, third, and fifth pages of the reprinted printing medium 22. Therefore, the inspection indicator 42 can determine the upper right corner area of ​​the first, third, and fifth pages of the reprinted printing medium 22 as a specific area 50 based on the subsequent printing data.

[0068] When multiple subsequent images are printed separately on a single page of the reprinted printing medium 22, the specific area indicated by the specific area information may also be multiple areas within a single page. Furthermore, when the reprinted printing medium 22 comprises multiple pages and the subsequent images on each page are printed in different areas, the inspection instruction unit 42 sends information that associates the page number of the reprinted printing medium 22 with the specific area 50 on the page where the subsequent image is printed as specific area information to the reprint inspection device 18.

[0069] Furthermore, if the inspection instruction unit 42 sends the specific area information as inspection information to the reprint inspection device 18 instead of the specific color information, the subsequent image may not be printed in a specific color.

[0070] The overlap determination unit 44 and the data combination unit 46 will be described later.

[0071] Figure 6 This is a schematic diagram of the structure of the print inspection device 18. In this embodiment, the print inspection device 18 is connected to the subsequent image forming apparatus 16, but the print inspection device 18 and the subsequent image forming apparatus 16 can also be separately provided and communicatively connected to each other. In addition, the print inspection device 18 can be any device as long as it performs the functions described below.

[0072] The communication interface 60 may include, for example, a network adapter or a dedicated adapter for connecting the print inspection device 18 to other devices (especially the subsequent image forming apparatus 16 and the print inspection device 18). The communication interface 60 functions to communicate with other devices. For example, the communication interface 60 receives advance printing data and subsequent printing data from the printing control device 12. Furthermore, the communication interface 60 receives the inspection information and inspection instructions from the printing control device 12. Finally, the communication interface 60 sends the inspection results of the print inspection process to the printing control device 12.

[0073] The scanner 62 is configured to include, for example, a light source and a charge-coupled device (CCD) image sensor. The scanner 62 optically reads the reprinted printed medium 22 on which the reprinted image is printed, to obtain read image data representing the reprinted image (hereinafter referred to as "reprinted image data"). Alternatively, in order to obtain the reprinted image data from the reprinted printed medium 22, a camera that captures images of the reprinted printed medium 22 may be provided in the reprint inspection device 18 instead of the scanner 62.

[0074] The color sensor 64 is a sensor capable of detecting a specified color. A photoelectric sensor can be used as the color sensor 64. The photoelectric sensor can be a sensor whose detected color can be set. Alternatively, multiple photoelectric sensors capable of detecting a single color can be provided, and only the photoelectric sensor detecting the set color can be operated, thereby enabling the detection of the set color. This type of photoelectric sensor can directly sense the printed media 22 after reprinting. In this case, the scanner 62 is not required to acquire the reprinted image data. Furthermore, the color sensor 64 can also be a color recognition sensor with a color detection function that detects the color of each pixel in the reprinted image data. With this type of color recognition sensor, since the color of each pixel can be recognized, only the pixels of the set color can be detected by setting the color to be detected.

[0075] The memory 66 may include, for example, ROM or RAM. The memory 66 may be provided independently of the processor 72 (described later), or at least partially within the processor 72. The memory 66 stores a print tracking inspection program for operating the various parts of the print tracking inspection device 18. Furthermore, the memory 66 temporarily holds the print tracking image data acquired by the scanner 62.

[0076] OK tray 68 and NG tray 70 are trays for discharging the reprinted printing media 22 after the reprinting process has been checked by the processor 72 (described later). Reprinted printing media 22 whose reprinting process inspection result is "good" are discharged to OK tray 68, and reprinted printing media 22 whose reprinting process inspection result is "bad" are discharged to NG tray 70.

[0077] Processor 72 refers to a processing device in a broad sense, comprising at least one general-purpose processing device (such as a CPU) and a special-purpose processing device (such as a GPU, ASIC, FPGA, or programmable logic device). Processor 72 may also not consist of a single processing device, but rather be configured through the cooperation of multiple processing devices located in physically separate locations. Figure 6 As shown, the processor 72 performs the functions of the image detection unit 74 and the defect detection unit 76 through the print inspection program stored in the memory 66.

[0078] The image detection unit 74 performs processing to detect subsequent images from the reprinted printing medium 22 based on the inspection information received from the printing control device 12.

[0079] First, the case where the specific color information is received from the printing control device 12 as inspection information will be explained. As described above, the specific color represented by the specific color information received from the printing control device 12 is the color of the subsequent image. Therefore, after the image detection unit 74 sets the color detected by the color sensor 64 as the color represented by the specific color information, it detects the specific color from the reprinted image data acquired by the scanner 62, or directly from the reprinted printing medium 22, via the color sensor 64. This enables the detection of the subsequent image. For example, when the reprinted printing medium 22 is... Figure 4B In the case of the printing medium shown, the text "1" to "6" which serves as the preceding image is printed in a color other than a specific color (e.g., black), while the image of the batter, which serves as the subsequent image, is printed in a specific color (e.g., red). By setting the color detected by the color sensor 64 to the specific color, thus... Figure 7 As shown, only subsequent images are detected.

[0080] When specific color information represents multiple colors, i.e., when subsequent images are printed in multiple colors, the image detection unit 74 can detect subsequent images from the reprinted printing medium 22 by setting the color detected by the color sensor 64 to the multiple colors. Furthermore, when the specific color information is information that associates the page number of the reprinted printing medium 22 with a specific color, i.e., when the reprinted printing medium 22 contains multiple pages and the subsequent images on each page are different specific colors, the image detection unit 74 changes the specific color detected by the color sensor 64 for each page of the reprinted printing medium 22 (or reprinted image data) based on the specific color information, thereby enabling the detection of subsequent images from each page of the reprinted printing medium 22.

[0081] Upon receiving the specific area information as inspection information from the printing control device 12, the image detection unit 74 cuts out and extracts the specific area 50 represented by the specific area information (see reference) from the post-printing image data acquired by the scanner 62. Figure 5 Therefore, subsequent images can be detected. Furthermore, when the specific region information is information that associates the page number of the reprinted printing medium 22 with the specific region 50, that is, when the reprinted printing medium 22 contains multiple pages and the subsequent images of each page are printed in different regions, the image detection unit 74 cuts out different specific regions 50 for each page of the reprinted image data based on the specific region information, thereby enabling the detection of subsequent images from each page of the reprinted printing medium 22.

[0082] Furthermore, upon receiving specific color information and specific area information as inspection information from the printing control device 12, the image detection unit 74 causes the color sensor 64 to detect a specific color from a specific area 50 in the reprinted printing medium 22 or the reprinted image data, thereby detecting the subsequent image. This reduces the processing load for detecting the subsequent image compared to using the color sensor 64 to sense the entire reprinted printing medium 22 or the reprinted image data. Moreover, considering the case where the specific area 50 contains at least a portion of an image other than the subsequent image (i.e., a preceding image), detecting a specific color from the specific area 50 using the color sensor 64 allows for the exclusion of at least a portion of the preceding image. Therefore, compared to simply cutting out a specific area 50 of the reprinted image data for detection as the subsequent image, the subsequent image can be detected with higher accuracy.

[0083] The processing performed by the image detection unit 74 thereby detects the image in the post-printing medium 22. Figure 7 The subsequent images shown. Comparison. Figure 4A and Figure 7 It is known that as long as proper follow-up processing is performed in the subsequent image forming apparatus 16, the subsequent printing data will be consistent with the subsequent image detected from the follow-up printing medium 22.

[0084] The defect detection unit 76 detects defects in the follow-up printing process in the subsequent image forming apparatus 16 by comparing the subsequent image detected by the image detection unit 74 with the subsequent printing data. The subsequent printing data can be acquired from the printing control device 12 or the subsequent image forming apparatus 16. The defect detection unit 76 converts the subsequent printing data acquired from the printing control device 12 or the subsequent image forming apparatus 16 into a raster format and compares the raster format subsequent printing data with the subsequent image detected by the image detection unit 74. Alternatively, the defect detection unit 76 can also acquire the subsequent printing data that has been converted to a raster format from the subsequent image forming apparatus 16.

[0085] As a specific method for comparing subsequent images with subsequent printing data, known methods can be employed. For example, pattern matching can be performed between the subsequent image and the subsequent printing data to detect differences. Alternatively, features (e.g., edges) can be detected separately from the subsequent image and the subsequent printing data, and the detected features can be compared with each other. Alternatively, the pixel values ​​(brightness values, color values, etc.) of pixels in the subsequent image can be compared with the pixel values ​​of corresponding pixels in the subsequent printing data.

[0086] As described above, as long as proper follow-up processing is performed in the subsequent image forming apparatus 16, the subsequent printing data and the subsequent image detected from the follow-up printing medium 22 should be consistent. Therefore, if the similarity between the detected subsequent image and the subsequent printing data is above a predetermined threshold, the defect detection unit 76 can determine that the follow-up processing related to the follow-up printing medium 22 is "good". On the other hand, if the similarity between the detected subsequent image and the subsequent printing data is below the predetermined threshold, the defect detection unit 76 can determine that the follow-up processing related to the follow-up printing medium 22 is "defective".

[0087] When the reprinted printing medium 22 contains multiple pages, the defect detection unit 76 compares the subsequent image detected by the image detection unit 74 with the subsequent printing data for each page. Specifically, it compares the subsequent image detected from a certain page of the reprinted printing medium 22 with the subsequent printing data corresponding to that page. Thus, the defect detection unit 76 can detect defects in the reprinting process for each page.

[0088] The reprinted printing media 22 (or pages of the reprinted printing media 22) that are determined to be "good" by the defect detection unit 76 are discharged to the OK tray 68. The reprinted printing media 22 (or pages of the reprinted printing media 22) that are determined to be "defective" by the defect detection unit 76 are discharged to the NG tray 70.

[0089] Furthermore, the defect detection unit 76 sends information indicating the inspection results of the reprint processing to the printing control device 12. The processor 38 of the printing control device 12 then displays the inspection results on a display 34 or similar device to notify the user.

[0090] According to this embodiment, the data used for detecting defects in the reprinting process is sufficient only from the subsequent image and subsequent printing data detected in the reprinted printing medium 22. Therefore, compared to the conventional case where three data points—previous printing data, subsequent printing data, and the reprinted image—are compared, the amount of data in the comparison processing object can be reduced. By reducing the amount of data in the comparison processing object, the processing volume and processing time of the comparison processing are reduced, that is, the processing volume and processing time of the reprinting process are reduced.

[0091] Hereinafter, the overlap determination unit 44 and the data connection unit 46 of the printing control device 12 (see reference) will be described. Figure 2 (This will be explained.)

[0092] The overlap determination unit 44 determines whether the preceding image and the subsequent image overlap in the reprinted printing medium 22 after the reprinting process is performed, based on the preceding printing data and the subsequent printing data. In other words, the overlap determination unit 44 determines whether the subsequent image was printed on top of the preceding image during the reprinting process. The preceding printing data has information indicating the shape or printing position of the preceding image on the printing medium 20 before reprinting, and the subsequent printing data has information indicating the shape or printing position of the subsequent image on the reprinted printing medium 22. Therefore, the overlap determination unit 44 can determine whether the preceding image and the subsequent image overlap in the reprinted printing medium 22 based on the preceding printing data and the subsequent printing data.

[0093] When the reprinted printing medium 22 contains multiple pages, the overlap determination unit 44 determines whether the preceding image and the subsequent image overlap for each page. For example, when the preceding printing data and the reprinted printing medium 20 are respectively... Figure 3A , Figure 3B As shown, and the subsequent printing data is Figure 8 In the case shown, the reprinted printing medium 22 becomes Figure 9 As shown. At this time, the overlap determination unit 44 determines that in the first, second, fifth and sixth pages of the reprinted printing medium 22, the preceding image and the subsequent image do not overlap, but in the third and fourth pages of the reprinted printing medium 22, the preceding image and the subsequent image overlap.

[0094] When the overlap determination unit 44 determines that the preceding image and the subsequent image overlap in the reprinted printing medium 22, the data combining unit 46 combines the preceding printing data and the subsequent printing data to generate combined data. Combining the preceding printing data and the subsequent printing data means that the combined data represents the reprinted image where the preceding image shown in the preceding printing data and the subsequent image shown in the subsequent printing data are aligned and overlapped. When the reprinted printing medium 22 contains multiple pages, the data combining unit 46 may also generate combined data only for pages where the preceding and subsequent images overlap, and not for pages where the preceding and subsequent images do not overlap. For example, when the reprinted printing medium 22 is... Figure 9 In the case shown, the data binding unit 46 does not generate binding data for the first, second, fifth, and sixth pages of the reprinted printing medium 22. Instead, it combines the third page of the previously printed data with the third page of the subsequent printed data to generate binding data for the third page, and combines the fourth page of the previously printed data with the fourth page of the subsequent printed data to generate binding data for the fourth page.

[0095] The data binding unit 46 sends the generated binding data as inspection information to the reprint inspection device 18. Furthermore, when the reprinted printing medium 22 contains multiple pages, the data binding unit 46 associates the page number of the reprinted printing medium 22 with the binding data of that page and sends it to the reprint inspection device 18. At this time, regarding pages where the preceding image and the subsequent image do not overlap (… Figure 9 The inspection information for pages 1, 2, 5, and 6 is at least one of the specific color information and specific region information, regarding pages where the preceding image overlaps with the subsequent image. Figure 9 The inspection information (on the third and fourth pages) is combined with the data.

[0096] When the preceding image and subsequent image in the reprint inspection device 18 do not overlap, the defect detection unit 76 detects defects in the reprint process by comparing the subsequent image detected by the image detection unit 74 with the subsequent printing data. However, when the preceding image and subsequent image overlap in the reprinted printing medium 22, the defect is detected by comparing the preceding printing data, the subsequent printing data, and the reprinted image. In this embodiment, the defect detection unit 76 detects defects in the reprint process by comparing the combined data received from the printing control device 12 with the reprinted image data acquired by the scanner 62 through optical reading of the reprinted printing medium 22.

[0097] The comparison between the combined data and the reprinted image data can also be done using the same method as the comparison between subsequent images and subsequent printing data.

[0098] If the similarity between the combined data and the reprinted image data is above a predetermined threshold, the defect detection unit 76 can determine that the reprinting process related to the reprinted printing medium 22 is "good". On the other hand, if the similarity between the combined data and the reprinted image data is below a predetermined threshold, the defect detection unit 76 can determine that the reprinting process related to the reprinted printing medium 22 is "defective".

[0099] Furthermore, regarding the inspection information received from the printing control device 12, consider the case where the inspection information for a portion of the multi-pages of the reprinted printing medium 22 is specific color information or specific area information, and the inspection information for other pages is combined data; that is, the reprinted printing medium 22 contains multiple pages, and only in a portion of the multiple pages does the preceding image overlap with the subsequent image. In this case, the defect detection unit 76 detects defects in the reprinting process on pages where the preceding and subsequent images do not overlap, based on the specific color information or specific area information as inspection information, by comparing the subsequent image detected by the multi-image detection unit 74 with the subsequent printing data. On the other hand, the defect detection unit 76 detects defects in the reprinting process on pages where the preceding and subsequent images overlap, by comparing the combined data as inspection information with the reprinted image data acquired by the scanner 62.

[0100] For example, after reprinting, the printing medium 22 is Figure 9 In the case shown, since the preceding image and the subsequent image do not overlap in the first, second, fifth and sixth pages, the defect detection unit 76 compares the subsequent image detected by the image detection unit 74 with the subsequent printing data. Since the preceding image and the subsequent image overlap in the third and fourth pages, the defect detection unit 76 compares the combined data with the image data after reprinting, thereby detecting defects in the reprinting process.

[0101] Furthermore, in this embodiment, as a method for comparing preliminary printing data, subsequent printing data, and the reprinted image, the combined data of preliminary printing data and subsequent printing data generated by the data combining unit 46 of the printing control device 12 is compared with the reprinted image data, but this method is not limited to this. For example, the defect detection unit 76 may also obtain preliminary printing data and subsequent printing data from the printing control device 12, and compare the difference image data obtained by subtracting the preliminary printing data from the reprinted image data with the subsequent printing data, or compare the difference image data obtained by subtracting the subsequent printing data from the reprinted image data with the preliminary printing data.

[0102] As described above, the image detection unit 74 of the reprint inspection apparatus 18 detects subsequent images by detecting a specific color from the reprinted image data or the reprinted printing medium 22. However, when the preceding image and the subsequent image overlap in the reprinted printing medium 22, the color of the overlapping portion is not necessarily limited to the specific color specified as the color for printing the subsequent image in the reprint process. Therefore, when the preceding image and the subsequent image overlap in the reprinted printing medium 22, the image detection unit 74 may not be able to detect the subsequent image optimally by detecting a specific color from the reprinted printing medium 22.

[0103] Furthermore, when the image detection unit 74 cuts out a specific region 50 from the reprinted image data (see reference...) Figure 5 When detecting subsequent images, if the preceding and subsequent images overlap in the reprinted printing medium 22, the specific region 50 may contain not only the subsequent image but also at least a portion of the preceding image. Therefore, even when the preceding and subsequent images overlap in the reprinted printing medium 22, the image detection unit 74 may not be able to effectively detect the subsequent image by cutting out the specific region 50 from the reprinted image data.

[0104] Therefore, in this embodiment, when the preceding image and the subsequent image overlap in the reprinted printing medium 22, defects in the reprinting process are detected by comparing the preceding printing data, the subsequent printing data, and the reprinted image.

[0105] The following is based on Figure 10 The flowchart shown illustrates the processing flow of the printing control device 12 in this embodiment. Furthermore, it is assumed that the preliminary printing data and subsequent printing data associated with the flowchart represent preliminary and subsequent images of multiple pages.

[0106] In step S10, in the printing control device 12, the processor 38 selects the first page of the multi-page array represented by the preceding printing data and the subsequent printing data.

[0107] In step S12, the overlap determination unit 44 determines whether the preceding image and the subsequent image overlap on the selected page based on the preceding printing data and the subsequent printing data.

[0108] If the preceding image and the subsequent image do not overlap, the process proceeds to step S14. In step S14, the inspection instruction unit 42 obtains specific color information, representing the color of the printed subsequent image (i.e., a specific color), as inspection information based on subsequent printing data. Alternatively, or in addition to this, the inspection instruction unit 42 obtains specific area information, representing the area of ​​the printed subsequent image (i.e., a specific area), as inspection information based on subsequent printing data. The inspection instruction unit 42 retains the obtained inspection information (at least one of the specific color information and the specific area information) in association with the page number.

[0109] If the preceding image and the subsequent image overlap, the process proceeds to step S16. In step S16, the data combining unit 46 combines the preceding printing data of the page with the subsequent printing data of the page to obtain combined data of the page as inspection information. The inspection instruction unit 42 retains the obtained inspection information (combined data) in association with the page number.

[0110] In step S18, the processor 38 determines whether the acquisition and processing of inspection information for all pages has been completed.

[0111] If the processing of all pages has not yet been completed, proceed to step S20, where the processor 38 selects the next page. Next, the processing of steps S12 to S16 is performed on the next page.

[0112] If the processing of all pages has been completed, proceed to step S22. In step S22, the inspection instruction unit 42 sends the inspection information associated with each page and the inspection instruction for the reprint processing to the reprint inspection device 18.

[0113] The following is based on Figure 11 The flowchart shown illustrates the processing flow of the print inspection device 18 in this embodiment.

[0114] In step S30, the processor 72 of the reprint inspection device 18 selects the first page of the reprinted printing medium 22 as the object of inspection.

[0115] In step S32, the defect detection unit 76 determines the type of inspection information of the page received from the printing control device 12.

[0116] If the inspection information of the page is specific color information or specific area information, then proceed to step S34. In step S34, the image detection unit 74 detects subsequent images based on the inspection information from the reprinted image data obtained by the scanner 62 or directly from the reprinted printing medium 22.

[0117] Next, in step S36, the defect detection unit 76 compares the subsequent image detected in step S34 with the subsequent printing data received from the printing control device 12.

[0118] If the inspection information of the page is combined data, then proceed to step S38, in which the defect detection unit 76 compares the combined data with the reprinted image data acquired by the scanner 62.

[0119] In step S40, the defect detection unit 76 determines the inspection result of the reprinting process for the page. Specifically, if the similarity between the subsequent image and the subsequent printing data, or the similarity between the combined data and the reprinted image data, is above a predetermined threshold, the defect detection unit 76 considers the inspection result of the reprinting process to be "good". On the other hand, if the similarity between the subsequent image and the subsequent printing data, or the similarity between the combined data and the reprinted image data, is below a predetermined threshold, the defect detection unit 76 considers the inspection result of the reprinting process to be "defective".

[0120] If the inspection result is "good", proceed to step S42, in which the processor 72 discharges the pages of the reprinted printing medium 22 to the OK tray 68.

[0121] If the inspection result is "unsatisfactory", proceed to step S44, in which the processor 72 discharges the page of the reprinted printing medium 22 to the NG tray 70.

[0122] In step S46, the processor 72 determines whether the check process for the reprinting of all pages has been completed.

[0123] If the inspection process for all pages has not yet been completed, proceed to step S48, where the processor 72 selects the next page. Then, the processes of steps S32 to S44 are performed on the next page.

[0124] If the inspection process for all pages has been completed, proceed to step S50, in which the defect detection unit 76 sends the inspection results for the reprint processing of each page to the printing control device 12.

[0125] The embodiments of this disclosure have been described above, but this disclosure is not limited to the described embodiments. Various changes can be made as long as they do not depart from the spirit of this disclosure.

[0126] For example, in this embodiment, the printing control device 12 controls the inspection of the follow-up printing process, but the processing related to the inspection of the follow-up printing process can also be performed within the follow-up printing inspection device 18. That is, the follow-up printing inspection device 18 can also have the functions of the inspection indication unit 42, the overlap determination unit 44, and the data combination unit 46 that are present in the printing control device 12. In this case, the follow-up printing inspection device 18 appropriately receives the advance printing data from the printing control device 12 or the advance image forming device 14, and then receives the subsequent printing data from the printing control device 12 or the subsequent image forming device 16 before performing the processing.

[0127] When the reprint inspection device 18 has the aforementioned functions, consider the case where the reprint inspection device 18 cannot obtain preliminary printing data from the printing control device 12 and the preliminary image forming device 14. In this case, the processor 72 of the reprint inspection device 18 can also use image data obtained by optically reading the pre-reprint printing medium 20 as preliminary printing data. The pre-reprint printing medium 20 can be read by the scanner 62 of the reprint inspection device 18, or by other optical reading devices provided between the preliminary image forming device 14 and the subsequent image forming device 16, and the reprint inspection device 18 obtains the image data from the optical reading devices.

[0128] Furthermore, in this embodiment, the scanner 62, color sensor 64, and image detection unit 74 are provided in the print inspection apparatus 18, but they can also be provided in other apparatuses. For example, they can also be provided in the subsequent image forming apparatus 16.

Claims

1. A post-press inspection apparatus, characterized by, including a processor, the processor detects a defect of the overprint processing by comparing the preceding print data, the subsequent print data, and an image printed on the overprinted print medium, in a case where the preceding image and the subsequent image coincide with each other in the overprinted print medium, the subsequent image being detected from the overprinted print medium formed by the overprint processing which prints the subsequent image based on the subsequent print data on an overprint preceding print medium on which the preceding image based on the preceding print data is printed, the processor detects a defect of the overprint processing by comparing the subsequent image and the subsequent print data, in a case where the preceding image and the subsequent image do not coincide with each other in the overprinted print medium.

2. The overprint inspection apparatus according to claim 1, wherein in the overprint processing, the subsequent image is printed using a specific color which is not used in the preceding image, the subsequent image is detected from the overprinted print medium by a sensor which detects the specific color.

3. The overprint inspection apparatus according to claim 1 or 2, wherein the subsequent image is an image detected from a specific area determined based on the subsequent print data, the specific area being an area in which the subsequent image is printed on the overprinted print medium.

4. The overprint inspection apparatus according to claim 1, wherein image data acquired by optically reading the overprint preceding print medium is used as the preceding print data.

5. The overprint inspection apparatus according to claim 1 or 4, wherein a multi-page overprinted print medium is formed by the overprint processing based on multi-page subsequent print data for the overprint preceding print medium, the processor detects a defect of the overprint processing by comparing the subsequent image detected from the page and the subsequent print data, in a page in which the preceding image and the subsequent image do not coincide with each other, the processor detects a defect of the overprint processing by comparing the preceding image, the subsequent image, and an image printed on the overprinted print medium, in a page in which the preceding image and the subsequent image coincide with each other.

6. A computer-readable medium storing a program which causes a computer to execute a process, wherein the process is to detect a defect of overprint processing by comparing preceding print data, subsequent print data, and an image printed on an overprinted print medium, in a case where a preceding image and a subsequent image coincide with each other in the overprinted print medium, the subsequent image being detected from the overprinted print medium formed by the overprint processing which prints the subsequent image based on the subsequent print data on an overprint preceding print medium on which the preceding image based on the preceding print data is printed, and the process is to detect a defect of the overprint processing by comparing the subsequent image and the subsequent print data, in a case where the preceding image and the subsequent image do not coincide with each other in the overprinted print medium. ​ ​ 7. A post-print inspection method, characterized in that, It is to detect a defect of a re-printing process by comparing preceding printing data, subsequent printing data, and an image printed on a re-printed printing medium, in a case where a preceding image and a subsequent image overlap in the re-printed printing medium, the subsequent image being detected from the re-printed printing medium formed by using the re-printing process, the re-printing process being to print the subsequent image based on the subsequent printing data on a re-printed printing medium on which the preceding image based on the preceding printing data is printed, The re-printing inspection method detects a defect of the re-printing process by comparing the subsequent image and the subsequent printing data in a case where the preceding image and the subsequent image do not overlap in the re-printed printing medium.

Images