Inspection device, inspection method, and program

Abstract

To reduce false detection of a preprinted part of an inspection image.SOLUTION: The present invention is an inspection device that inspects printed matter in which a printing device prints print data on a printed medium on which a preprinted part has been printed in advance, and includes a print image reading unit that reads the printed medium and generates first image data 11, a mask image generating unit that generates a mask image 15 in which the preprinted part in the first image data is enlarged, a differential image generating unit that generates a differential image between the second image data generated by the print image reading unit reading the printed matter and a master image generated from the print data, a mask processing unit that performs mask processing on the differential image using the mask image, and a defect determination processing unit that determines whether the printed matter has a defect on the basis of the differential image after the mask processing is performed.SELECTED DRAWING: Figure 9

Description

[Technical field]

[0001] The present invention relates to an inspection device, an inspection method, and a program. [Background technology]

[0002] 2. Description of the Related Art Printing devices that form an image on paper based on print data and output a printout, and inspection devices that read the printout to generate an inspection image and compare the print data with the inspection image to inspect the quality of the printout, are known.

[0003] Also, a masking process is known for a print medium on which a preprinted portion such as a form has already been printed. When a printing device prints print data on preprinted paper, an inspection device reads the preprinted paper in advance to generate a mask image, and then masks the inspection image with the mask image to inspect whether the print data other than the preprinted portion has been properly printed (see, for example, Patent Document 1). Patent Document 1 discloses a technique for reading preprinted paper in advance and generating a mask image from the preprinted paper. The mask image makes it possible to prevent erroneous detection of the preprinted portion. Summary of the Invention [Problem to be solved by the invention]

[0004] However, with conventional technology, there is a risk that the preprinted portion of the inspection image will be detected as a defect. Due to misalignment of the preprinted portion on the print medium or skew of the print medium, the preprinted portion of the read inspection image may not completely match the preprinted portion of the print medium. This may result in the preprinted portion of the inspection image being erroneously detected as a defect.

[0005] In view of the above-mentioned problems, the present invention provides a technique for reducing erroneous detection of a preprint portion of an inspection image as a defect. [Means for solving the problem]

[0006] In view of the above problems, the present invention provides an inspection device for inspecting a printed matter on which print data is printed on a printing medium on which a preprint portion has already been printed, the inspection device comprising: a print image reading unit that reads the printing medium and generates first image data; a mask image generation unit that generates a mask image that enlarges the preprint portion in the first image data; a differential image generation unit that generates a differential image between second image data generated by the print image reading unit reading the printed matter and a master image generated from the print data; a mask processing unit that performs mask processing on the differential image using the mask image; and a defect determination processing unit that determines whether or not the printed matter has a defect based on the differential image after the mask processing. Effect of the Invention

[0007] The present invention can provide a technique for reducing erroneous detection of a preprinted portion of an inspection image as a defect. [Brief description of the drawings]

[0008] [Figure 1] FIG. 1 is a diagram illustrating an example of a system configuration of a printing system. [Diagram 2] 1 is a functional block diagram of a DFE. FIG. [Diagram 3] FIG. 2 is an example of a functional block diagram illustrating functions of a printer. [Figure 4] FIG. 2 is an example of a functional block diagram illustrating functions of an inspection device divided into blocks. [Diagram 5] FIG. 4 illustrates an example of job management information. [Figure 6] FIG. 13 is a diagram illustrating an example of an expansion / contraction filter. [Figure 7] FIG. 11 is a diagram illustrating an example of expansion processing range information. [Figure 8] FIG. 11 is a diagram showing an example of unmasked region information. [Figure 9] 11A to 11C are diagrams illustrating a method for generating a mask image in a preprint mask generation mode. [Figure 10]11A and 11B are diagrams illustrating a method for automatically creating a margin using a difference image. [Figure 11] 11A to 11C are diagrams illustrating a method for removing dirt on a preprinted paper from a mask area. [Figure 12] 13A and 13B are diagrams illustrating a method for adding a margin only to a specified area. [Figure 13] FIG. 13 is a diagram showing an example of a margin setting screen displayed on an operation unit. [Figure 14] FIG. 13 is a diagram showing an example of a margin setting screen in which an unmasked region has been set. [Figure 15] FIG. 13 is a diagram showing an example of a confirmation dialog box that is displayed when the decision button is pressed. [Figure 16] 13A and 13B are diagrams illustrating a method for setting a margin only in an expansion processing range. [Figure 17] 13A and 13B are diagrams illustrating a method for setting margins by switching between partial margin setting and full margin setting. [Figure 18] FIG. 11 is a flowchart illustrating a flow of generating a mask image by dilation processing. [Figure 19] FIG. 13 is a flowchart illustrating in detail a flow of mask image generation in an OR synthesis process. [Figure 20] FIG. 13 is an example of a flowchart illustrating the process of step S004 or S017 in detail. [Figure 21] FIG. 13 is an example of a flowchart illustrating a process in which a mask image generating unit changes an expansion level when a margin setting button (expansion button, contraction button) is pressed. [Figure 22] FIG. 11 is a flowchart illustrating an example of a process for setting an unmasked region. [Diagram 23] FIG. 13 is a flowchart illustrating an example of a process for deleting an unmasked region. [Figure 24] 13 is a flowchart illustrating a process performed when a margin setting range selection / cancellation button is pressed. FIG. [Diagram 25] FIG. 11 is a flowchart illustrating an example of a page switching process. [Figure 26] FIG. 13 is a flowchart illustrating an example of a process when a margin is determined. [Figure 27] FIG. 13 is a flowchart illustrating an example of a process performed when a cancel button is pressed. [Figure 28] 13 is an example of a flowchart illustrating a process in which the user I / F unit changes the type of frame line. [Figure 29] 13 is an example of a flowchart illustrating a process in which the user I / F unit changes the color of a frame line. [Diagram 30] 1 is a diagram illustrating a flow of printing, generation of an inspection image, generation of a difference image, mask processing, and inspection. [Diagram 31] 11A to 11C are diagrams illustrating a method for generating a mask image from a preprinted sheet containing an image in a preprinted mask generation mode. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0009] A printing system and an inspection method performed by the printing system will be described below as an example of an embodiment of the present invention.

[0010] <Testing procedure> First, the overall flow of inspection of a printed matter will be described with reference to Fig. 30. Fig. 30 is a diagram for explaining the flow of printing, generation of an inspection image, generation of a difference image, mask processing, and inspection.

[0011] (1) A printer prints prepared print data 61 on preprinted paper 62. The preprinted paper 62 is paper on which a format such as ruled lines has already been printed.

[0012] (2) The printer outputs a printout 63 in which the print data 61 is printed on preprinted paper 62. The inspection device inspects the quality of this printout 63.

[0013] (3) For this reason, the inspection device reads the printed matter 63 with a scanner or the like, and generates an inspection image 64 (an example of second image data).

[0014] (4) The inspection device generates a difference image 17, which is the difference between the inspection image 64 and a master image 65 generated from the print data 61. Therefore, when the print quality is ideal, only the format remains in the difference image 17. In Figure 30, a stain 29 that was caused during the printing process is present in the difference image. The stain 29 may be caused during printing or during reading.

[0015] (5) The inspection device masks the difference image 17 using a mask image 15 that has been generated in advance based on a preprint image (an example of first image data) obtained by reading a preprint paper.

[0016] (6) In an ideal case, the masked difference image 18 would be pure white, and in this case, it would be determined that there is no abnormality. In Figure 30, it can be seen that there is a stain 29 in the masked difference image 18, so that an abnormality in the print can be detected.

[0017] However, due to misalignment of the format on the preprinted paper, skew of the preprinted paper, etc., the format part of the read inspection image may not completely match the format part of the mask image. For this reason, the inspection device may not be able to completely mask the format part of the inspection image, and may erroneously detect the format part as a defect.

[0018] Therefore, the printing system of this embodiment performs a process to enlarge the format portion in the mask image. The enlargement process can be a margin setting process or a flag image synthesis process described later. Since the format portion is enlarged by these processes, even if distortion occurs due to misalignment of the format on the preprinted paper or skew of the preprinted paper, the format portion in the inspection image can be masked, and the format portion can be prevented from being erroneously detected as a defect.

[0019] <Terminology> Expansion processing is a process in which, if there is at least one pixel with a pixel value of 1 around the pixel of interest, the pixel is output with a pixel value of 1 at the coordinates of the output image corresponding to the pixel of interest. Contraction processing is a process in which, if there is at least one pixel with a pixel value of 0 around the pixel of interest, the pixel is output with a pixel value of 0 at the coordinates of the output image corresponding to the pixel of interest. In other words, expansion processing expands pixels with a pixel value of 1, and contraction processing narrows pixels with a pixel value of 1 (expands pixels with a pixel value of 0).

[0020] Margin means an extra or allowance, and means that the masking process is carried out wider than usual.

[0021] The print medium is a printing paper on which a preprinted portion such as a form has already been printed. The print medium includes, for example, forms, postcards, etc. on which ruled lines, input fields for letters and numbers, images such as a company logo, or advertisements are printed. The preprinted portion includes forms, input fields, images such as a company logo, advertisements, etc. that are printed on the print medium in advance. In this embodiment, the print medium will be described using the term preprinted paper.

[0022] The inspection image is an image generated by reading a printed matter printed on preprinted paper based on print data, and is the image that is the subject of quality control. The part of the inspection image that is the subject of inspection is the part of the inspection image that is not masked by the mask image (the part other than the mask image).

[0023] A mask image is an image generated by reading preprinted paper. Therefore, the mask image is an image of the printed form portion. The inspection device masks the inspection image with the mask image, making it possible to inspect the image quality of the printout resulting from the print data without including the form portion. Masking refers to image processing that removes unnecessary parts from the image data. The unnecessary parts are specified by the mask image.

[0024] The master image is an image obtained by converting an image that has been RIP-processed based on print data into RGB. In this embodiment, the master image is used when generating a mask image and when generating a difference image from an inspection image. However, a RIP image is not essential when generating a mask image.

[0025] The detection mode during actual printing is a mode in which an actual printed matter is printed and the quality of the printed matter (which may be a full print or a random inspection) is inspected. The preprint mask generation mode is a mode in which a mask image is generated.

[0026] <System configuration example> Fig. 1 shows a schematic system configuration diagram of a printing system 100. The system configuration in Fig. 1 is just an example, and any configuration capable of performing the defect detection described in this embodiment may be used.

[0027] The printing system 100 has a printer 101, an inspection device 103, and a stacker 104. All or two of the printer 101, the inspection device 103, and the stacker 104 may be integrated. The printer 101 is a device that receives data such as characters, images, or figures, and prints the data on paper or the like. The printer 101 may also be called a printing device, an MFP (Multifunction Peripheral / Printer / Product), a multifunction machine, or the like.

[0028] An operation unit 102 of the printer 101 is installed on the top surface of the printer 101. The operation unit 102 has a display (touch panel) and a keyboard, and displays an operation screen. The operation unit 102 displays the operation screen of the printing system 100, and accepts various operations from the user.

[0029] The printer 101 receives a print job including an RIP image from an external device such as a DFE (Digital Front End) or a PC (Personal Computer) described later, or receives an instruction to execute a print job stored in the printer 101. In this embodiment, as an example, the RIP image is 8 bit 600 dpi for each of CMYK.

[0030] The printer 101 obtains paper from the paper feed unit 105 according to the contents of the print job instructed to be executed, and conveys the paper along the path indicated by the dotted line in the figure. The printer 101 forms an image on the paper using drums 113, 114, 115, and 116. The drums 113, 114, 115, and 116 respectively superimpose K (black), C (cyan), M (magenta), and Y (yellow) toner images on the belt 111, transfer the color toner images to the paper conveyed to the roller 112, and fix the toner images on the paper by heat and pressure using roller 117. In the case of single-sided printing, the paper is directly discharged to the inspection device 103. In the case of double-sided printing, the paper is reversed by a reversing path 118 and conveyed to the roller 112, where the color toner images are transferred and fixed to the other side of the paper by the drums 113, 114, 115, and 116, and then discharged to the inspection device 103.

[0031] The inspection device 103 is a device that inspects the print quality of a printout output by the printer 101. The inspection device 103 has an operation unit 133 of the inspection device 103. The function of the operation unit 133 may be the same as that of the operation unit 102. The inspection device 103 does not need to have the operation unit 133, and the operation unit 102 of the printer body may also serve as this unit. The operation unit 133 of the inspection device 103 may also be a PC connected via a LAN or the like. In this case, the PC displays the inspection results using, for example, a web browser or a dedicated app.

[0032] The inspection device 103 reads the image on the paper discharged from the printer 101, one side at a time, using reading devices 131 and 132 (an example of a reading unit), transports the paper in the direction of the arrow on the path, and discharges the paper to a stacker 104. In this embodiment, as an example, the read image is 8 bit and 200 dpi for each of RGB.

[0033] The stacker 104 stacks (piles up) the paper discharged from the inspection device 103 on a tray 141 .

[0034] <dfe> The DFE 150 will be described with reference to Fig. 2. The DFE 150 is a general term for a device that processes data to be input to a printer. The DFE 150 generates RIP data (raster data) to be printed by the printer 101 from print data such as PostScript data.

[0035] Fig. 2 is an example of a functional block diagram of the DFE 150. The printer 101 in Fig. 1 and a DFE panel 151 for displaying a user interface are connected to the DFE 150. The DFE panel 151 is a user interface having a display (touch panel) and a keyboard.

[0036] The DFE 150 has a system control unit 501, a network I / F unit 502, a user I / F unit 505, a storage unit 503, a printer I / F unit 504, and a colorimeter I / F unit 506. The DFE 150 has a computer that performs control and processing. Each functional unit of the DFE 150 is a function or means realized by the CPU executing instructions included in one or more programs installed in this computer.

[0037] A user I / F unit 505 included in the DFE 150 generates a screen to be displayed on the DFE panel 151 using the UI display information, and displays it on the DFE panel 151. The UI display information includes a plurality of display components that configure the screen and their layout.

[0038] A network I / F unit 502 included in the DFE 150 is a communication interface that connects the DFE 150 to a LAN. The network I / F unit 502 receives a print job from the LAN and transmits it to the system control unit 501.

[0039] Furthermore, a print job may be stored in storage unit 503, and system control unit 501 may acquire the print job from storage unit 503. That is, system control unit 501 may receive the print job via network I / F unit 502, or may acquire the print job from storage unit 503.

[0040] The DFE 150 includes a system control unit 501. The system control unit 501 controls the entire DFE 150. The system control unit 501 includes a job information processing unit 551, a RIP processing unit 552, a storage unit 553, and a tone correction data generating unit 554.

[0041] The job information processing unit 551 manages the status of the print job, input to the printer 101, progress of the print job (acquired from the printer 101), etc., as job management information related to the print job in the storage unit 553. The job information processing unit 551 inputs print job data that combines job management information and RIP image data to the printer 101. The storage unit 553 stores print job data related to the print job (for example, job ID, file name, job registration date and time, job owner, etc.).

[0042] The gradation correction data generating unit 554 adjusts the print data so that it is printed with the same gradation, density, and color as the original. For example, the gradation correction data generating unit 554 increases or decreases the gradation, increases or decreases the density, or increases or decreases the warm colors or blue colors.

[0043] The RIP processor 552 generates RIP data for printing print data such as PostScript data by the printer 101. The RIP data is halftone dot data (whether or not to print dots) for each color of toner.

[0044] Furthermore, a printer I / F unit 504 included in the DFE 150 is an interface for communicating with the printer 101. The printer I / F unit 504 transmits to the printer 101 print job data that the system control unit 501 has decided to input.

[0045] Furthermore, a colorimeter I / F unit 506 included in the DFE 150 is an interface for communicating with the colorimeter 152. The colorimeter I / F unit 506 transmits colorimetric data generated by the colorimeter 152 measuring the color of a color chart to the printer 101. The colorimeter 152 is a measuring device that quantitatively measures color.

[0046] <About the printer functions> 3 is a functional block diagram for explaining the functions of the printer 101. The printer 101 has a system control unit 201, a user I / F unit 202, a DFE I / F unit 207, a network I / F unit 203, an external I / F control unit 204, a storage unit 205, an image processing control unit 208, a printing control unit 209, and a mechanism control unit 206. The printer 101 has a computer for performing control and processing. Each functional unit of the printer 101 is a function or means realized by a CPU executing instructions included in one or more programs installed in this computer.

[0047] The system control unit 201 controls the entire printer 101. The system control unit 201 is connected to a user I / F unit 202, a DFE I / F unit 207, a network I / F unit 203, an external I / F control unit 204, a storage unit 205, an image processing control unit 208, a printing control unit 209, and a mechanism control unit 206.

[0048] The user I / F unit 202 is an interface for connecting the system control unit 201 and the operation unit 102 shown in FIG.

[0049] The DFE I / F unit 207 is an interface that enables communication (for example, reception of print job data) between the system control unit 201 and the DFE 150 shown in FIG.

[0050] A network I / F unit 203 is an interface for connecting the system control unit 201 to a network such as a LAN and for the printer 101 to communicate with devices on the network.

[0051] The external I / F control unit 204 is an interface for the printer 101 to communicate with other devices (the inspection device 103, the stacker 104, etc.).

[0052] The storage unit 205 is a storage unit realized by a hard disk drive (HDD), a solid state drive (SSD), etc. The storage unit 205 stores, for example, print job data.

[0053] A mechanism control unit 206 controls each mechanism within the printer 101, such as paper transport within the printer 101, the transfer process, and double-sided / single-sided printing control.

[0054] The printing control unit 209 instructs the mechanism control unit 206 to control the timing of each mechanism, and also performs overall control of image formation on paper. The image processing control unit 208 processes the image transferred by the mechanism control unit 206.

[0055] The system control unit 201 has a memory 251, a job processing unit 252, a RIP processing unit 253, and a job information generating unit 254. The memory 251 is a working memory for the system control unit 201. When the job information generating unit 254 receives print job data from the DFE 150, it generates a job ID in the printer, the reception date and time, progress, and the like, and stores them in the storage unit 205. When the print job has not been RIP-processed, the RIP processing unit 253 performs RIP processing on the print data. The job processing unit 252 inquires of the printing control unit 209 about the availability of print jobs, and determines the print job to be executed from among the print job data stored in the storage unit 205 according to the priority and the like.

[0056] <Inspection equipment functions> 4 is a functional block diagram explaining the functions of the inspection device 103 by dividing them into blocks. The inspection device 103 has a system control unit 301, a master image generating unit 308, a difference image generating unit 309, a print image reading unit 307, an external I / F control unit 304, a user I / F unit 302, a storage unit 305, a network I / F unit 303, and a mechanism control unit 306. The inspection device has a computer that performs control and processing. Each functional unit of the inspection device 103 is a function or means realized by a CPU executing instructions included in one or more programs installed in this computer.

[0057] The system control unit 301 controls the entire inspection device 103. A master image generating unit 308, a differential image generating unit 309, a print image reading unit 307, an external I / F control unit 304, a user I / F unit 302, a storage unit 305, a network I / F unit 303, and a mechanism control unit 306 are connected to the system control unit 301.

[0058] The user I / F unit 302 is an interface for connecting the system control unit 301 and the operation unit 133 in Fig. 1. The user I / F unit 302 causes the information of the system control unit 301 to be displayed on the operation unit 133.

[0059] The network I / F unit 303 is an interface for connecting the system control unit 301 to a network such as a LAN.

[0060] The external I / F control unit 304 is an interface with other devices (for example, the printer 101, the stacker 104, etc.).

[0061] A mechanism control unit 306 controls the operation of each mechanism of the inspection device 103, such as paper transport, double-sided / single-sided reading of paper, and paper discharge.

[0062] The storage unit 305 is a storage means realized by an HDD, an SSD, etc. The storage unit 305 stores, for example, an inspection image, a flag image, a mask intermediate image, a mask image, a master image, and an inspection result, which will be described later.

[0063] The printed image reading unit 307 reads both sides of the paper conveyed from the printer 101 using the reading devices 131 and 132, and outputs an inspection image. The printed image reading unit 307 generates an inspection image in an actual printing detection mode described below, and generates a preprint image in a preprint mask generation mode. The actual printing detection mode is a mode in which a printed matter is inspected while a print job is being executed, and the preprint mask generation mode is a mode in which a mask image is generated from preprinted paper before execution of the print job starts.

[0064] In the detection mode during actual printing, the master image generating unit 308 changes the color space (CMYK to RGB) of the RIP image sent by the DFE 150. This RIP image is generated from print data to be formed on paper.

[0065] In the preprint mask generation mode, the master image generation unit 308 generates a master image that is entirely white. Therefore, in the preprint mask generation mode, a RIP image is not necessary. Note that the white in the master image refers to the white of the paper. The same applies hereinafter.

[0066] The difference image generating unit 309 generates a difference image in both the actual printing detection mode and the preprint mask generation mode. The difference image is generated by comparing a master image (print data) with an inspection image, or a master image (blank paper) with a preprint image. The difference image is an image that represents the difference in pixel value for each pixel of two images. In the actual printing detection mode, the RIP image is generated from the print data formed on paper, and the inspection image is a scanned copy of the printout, so that normally the pixel values ​​of the difference image will be less than the threshold value.

[0067] The system control unit 301 has a storage unit 351, a job management data processing unit 352, a flag image generation unit 356, a mask image generation unit 357, a mask processing unit 358, and a defect discrimination processing unit 355. The flag image generation unit 356 and the mask image generation unit 357 function in a preprint mask generation mode.

[0068] A flag image generating unit 356 performs threshold processing on the difference image to binarize it, thereby generating a “flag image.” The threshold value is stored in the storage unit 305, for example, and is read out to the storage unit 351 when processing is performed.

[0069] The mask image generation unit 357 applies a dilation / erosion filter (see FIG. 6) to the entire flag image or to a specified region. The image after application of the dilation / erosion filter is called a mask intermediate image. The mask intermediate image is intermediate data between the flag image and the mask image shown below. The mask intermediate image is stored in, for example, the storage unit 351. The dilation / erosion filter is stored in, for example, the storage unit 305, and is read out to the storage unit 351 when the filter process is executed.

[0070] Furthermore, the mask image generating unit 357 can generate a mask intermediate image by OR-composing a plurality of flag images. A dilation / erosion filter may be applied to this mask intermediate image.

[0071] The specified area to which the dilation / erosion filter is applied is defined in the dilation processing range information (see FIG. 7). The dilation processing range information is stored in the storage unit 305, for example, and is read out to the storage unit 351 when the dilation processing is executed. If there is no dilation processing range information (the initial state is the front surface), the mask image generation unit 357 applies the dilation / erosion filter to the entire flag image.

[0072] The mask image generating unit 357 refers to the unmasked region information (see FIG. 8) stored in the storage unit 351, for example, and unmasks a specified region in the masked intermediate image. The masked intermediate image after this processing is called a mask image. The mask image generating unit 357 does not process the masked intermediate image if there is no unmasked region information. The mask image is stored in the storage unit 305.

[0073] The following describes functions related to print jobs. Since these functions are related to print jobs, they are used in the actual printing detection mode.

[0074] In the actual printing detection mode, the system control unit 301 receives the print management information (included in the job management information) via the external I / F control unit 304 and stores it in the storage unit 351 in the system control unit 301. The job management data processing unit 352 extracts the post-processing machine information from the job management information shown in FIG. 5 and transmits it via the external I / F control unit 304 to the stacker 104, which is the post-processing device downstream of the inspection device 103. The job management data processing unit 352 reads out the print management information from the storage unit 351. The job management data processing unit 352 transfers the print management information to the master image generating unit 308, the difference image generating unit 309, the print image reading unit 307, and the mechanism control unit 306 so that they can process the print job. The transferred print management information is the job management information shown in FIG. 5 excluding the post-processing machine information.

[0075] In the actual printing detection mode, the system control unit 301 performs the following processes. The print image reading unit 307 reads the print (generates an inspection image). A differential image is generated between the inspection image by the differential image generation unit 309 and a master image generated from the print data (RIP data). Mask processing by the mask processing unit 358 using a mask image for the difference image. Defect discrimination processing by the defect discrimination processing unit 355 using a preset defect discrimination threshold value. The defect discrimination processing unit 355 judges whether or not an edge having an intensity greater than the defect discrimination threshold value is detected in the masked difference image. If an edge is detected, the defect discrimination processing unit 355 judges that there is an abnormality, and if not, it judges that there is no abnormality. The detected edge may have any shape, such as a point or a line.

[0076] <<Job management information>> 5 shows an example of job management information. This job management information is for when the printer 101 performs normal print processing (detection during actual printing mode). During print processing, print data is generated for each page by at least one of the DFE 150 and the printer 101. The print job is processed based on the job management information.

[0077] The job management information has the fields of parameter, remarks, and initial value. The parameter is the item name, the remarks is an explanation of the parameter, and the initial value indicates the value when the system control unit 201 of the printer 101 receives it.

[0078] The job creation source is information that indicates the job output source, and includes information on whether the job is a print job input from the DFE 150 or internal data of the printer 101.

[0079] The creation time is information about the date and time when the job creator created the job information.

[0080] The page ID is an identification number for a print page. The page ID is incremented by 1 for each page processed after the power is turned on. A numeric value is set for the page ID when printing is performed.

[0081] The print side identifies whether the print job is single-sided, double-sided, with the front side printed (duplex front), or the back side printed (duplex back).

[0082] The paper ID is identification information for the paper used for printing. In the case of double-sided printing, the page IDs printed on the same paper will have the same paper ID. The paper ID is incremented by +1 for each sheet of paper processed after the power is turned on. A numerical value is set for the paper ID when printing is executed.

[0083] The copy ID is identification information for each copy. The copy ID is incremented by 1 for each copy that is printed after the power is turned on. The copy ID is set to a value when printing is performed.

[0084] The job ID is identification information for each job. The job ID is incremented by 1 for each completed job output after the power is turned on. The job ID is set to a value when printing is performed.

[0085] The paper type is information about the type of paper used for printing. The paper size is information about the size of the paper. The job type indicates whether the print job is a print job subject to defect detection, a print job not subject to defect detection, or an interleaf for defect detection and identification.

[0086] <<Dilation / Erosion Filter>> Dilation / contraction processing using a dilation / contraction filter involves performing calculations on a binarized black-and-white image using a 3x3 pixel dilation / contraction filter, and determining the pixel at the coordinates of the output image corresponding to the pixel of interest (the center pixel) based on the pixel values ​​of the pixel of interest and its surrounding pixels (above, below, left, and right).

[0087] FIG. 6 shows an example of a dilation / erosion filter. The dilation / erosion filter is used in image processing to dilate a flag image. The dilation / erosion filter has a filter size of 3×3 required for dilating by 1 pix (pixel). To dilate by N pix, the mask image generating unit 357 repeats the filter process N times.

[0088] In the expansion process, if there is even one pixel with a pixel value of 1 in the vicinity of the pixel of interest, the pixel at the coordinates of the output image corresponding to the pixel of interest is replaced with 1. In the contraction process, if there is even one pixel with a pixel value of 0 in the vicinity of the pixel of interest, the pixel at the coordinates of the output image corresponding to the pixel of interest is replaced with 0. Here, replacement means changing the pixel value of the coordinates of the output image corresponding to the pixel of interest to 1 or 0.

[0089] <<Expansion processing range information>> FIG. 7 shows an example of the expansion processing range information. The expansion processing range information defines the area where the mask image generating unit 357 performs the expansion / contraction filter processing. The expansion processing range information has the x and y coordinates of the upper left vertex and the x and y coordinates of the lower right vertex of the area where the expansion / contraction filter processing is performed. A plurality of ranges may be specified on one page. Also, in consideration of specifying different ranges on the front and back of a printed matter, two pieces of expansion processing range information, one for the front side and one for the back side, may be defined. Also, the user can perform a reduction process on the expansion processing range, and the expansion processing range may be referred to as a reduction processing range.

[0090] The user can set the expansion processing range information as described below. In the initial state before the user sets the expansion processing range information, the expansion processing range information is the entire range of one page.

[0091] <<Unmask area information>> 8 shows an example of the unmasking area information. The unmasking area information defines an area where the mask processing unit 358 will unmask (not mask) the mask information. The unmasking area information has the x and y coordinates of the upper left vertex and the x and y coordinates of the lower right vertex of the area where the mask information will be unmasked. As will be described later, the unmasking area information is information for preventing the mask processing unit 358 from masking the difference image with dirt when dirt or the like is present in the mask image where only the format portion should be present.

[0092] Considering that the positions of stains differ between the front and back of a printed matter, two pieces of unmasked area information may be defined, one for the front side and one for the back side.

[0093] <Mask image generation example> Next, a method for generating the mask image 15 will be described with reference to Fig. 9. Fig. 9 is a diagram for explaining a method for generating the mask image 15 in the preprint mask generation mode. Image data generated by the print image reading unit 307 by reading the preprint paper is called a preprint image 11. Moreover, image data in which the entire surface is white generated by the master image generating unit 308 is called a master image 12.

[0094] (1) The differential image generating unit 309 generates a differential image between the preprint image 11 and the master image 12. Because the master image 12 is blank, the preprint image 11 may be used as the differential image without using the master image. However, by generating a differential image using the master image 12 in this manner, the inspection device 103 can make the process flow the same in the actual printing detection mode and the preprint mask generation mode.

[0095] (2) The flag image generating unit 356 binarizes the difference image to generate the flag image 13. In the flag image 13, pixels with a pixel value of 1 and a flag set correspond to the format portion.

[0096] (3) The mask image generating unit 357 performs an expansion process on the flag image 13 to generate a mask intermediate image 14. The expansion process thickens the ruled lines 22 in the mask intermediate image 14. The parts that are thicker than the ruled lines 22 in the preprint image 11 or the flag image 13 are the "margins." By doing so, the ruled lines 22 become thicker, so that even if the ruled lines in the inspection image are misaligned or skewed, they can be easily masked by the mask image. Also, even if the ruled lines 22 are interrupted in the mask intermediate image 14, they can be connected by the expansion process.

[0097] (4) The mask image generating unit 357 refers to the unmasked region information (see FIG. 8) and unmasks a specified region of the masked intermediate image 14, thereby generating a masked image 15. Although not shown in the figure, by unmasking, pixels with a pixel value of 1 in a part of the masked intermediate image 14 are replaced with pixels with a pixel value of 0 (see FIG. 11).

[0098] 9, the inspection device 103 expands the portion that already has pixels with a pixel value of 1, but the user may set a mask area at any location. For example, if a header or footer (date or page number) is printed, but not in the preprint image, the user may set a mask area for the header or footer if this is not to be inspected.

[0099] <Auto margin setting example> Next, a method for automatically setting a margin will be described with reference to Fig. 10. That is, in this embodiment, a margin can be set without the mask image generating unit 357 expanding using an expansion / contraction filter. Fig. 10 is a diagram for explaining a method for automatically creating a margin using a difference image.

[0100] (1) The difference image generating unit 309 generates n difference images from the n preprint images 11 and the n master images 12.

[0101] (2) The flag image generating unit 356 binarizes the difference image to generate n flag images 13.

[0102] The mask image generating unit 357 OR-combines n flag images 13 in the order they were generated. OR-combining refers to arranging pixels with a pixel value of 1 from n flag images 13 into one image. Since the format portion shifts slightly for each read image due to misalignment of the format on the preprinted paper or skew of the preprinted paper, the OR-combined composite flag image 16 can be used as a mask intermediate image 14 with a margin. As shown in FIG. 10, the OR-combined composite flag image 16 has thicker ruled lines 22 than one preprinted image 11.

[0103] (3) The mask image generating unit 357 may further perform an expansion process of the number of pixels designated by the user on the composite flag image 16. If the deviation between the read images is large, gaps may appear in the composite flag image 16, and these can be filled by the expansion process.

[0104] (4) The mask image generating unit 357 references the unmasked region information (see FIG. 8) and generates the mask image 15 by unmasking a specified region of the masked intermediate image 14.

[0105] <Example of how to deal with stains on pre-printed paper> Next, a method for removing stains on a preprinted paper from a mask area will be described with reference to Fig. 11. In this specification, components with the same reference numerals perform similar functions, so that the description of components that have already been described may be omitted or only differences may be described.

[0106] As shown in Fig. 11, if there is a stain 21 on the preprint paper, the stain 21 is also reflected in the preprint image 11 and flag image 13 generated by reading it. If the stain 21 is in a position that is actually to be inspected, that part may be masked, and there is a risk that the inspection image may not be extracted due to the masking process. Therefore, the mask image generating unit 357 sets an area where masking is not performed in the masking region information based on the coordinates of the stain 21 specified by the user. In the example of Fig. 11, the coordinates of the stain 21 are set in the masking region information.

[0107] Therefore, as shown in FIG. 11, the stain 21 remains in the mask intermediate image 14, but the stain 21 can be removed from the mask image 15.

[0108] <Add margins only to specified areas> FIG. 12 is a diagram explaining a method for adding margins only to specified areas. For example, since the deviation due to skew becomes large in the sub-scanning direction (mainly downstream), the user may wish to expand the margins only in those areas where the deviation becomes large. Alternatively, there may be cases where the margins should not be expanded in some parts of preprinted paper because the printing space for characters is narrow. In such cases, the user can specify the range for which the expansion process is to be performed by specifying the expansion process range 26, as described below.

[0109] The dilation processing range 26 specified by the user is registered in the dilation processing range information (FIG. 7). During the dilation processing, the mask image generation unit 357 can add a margin only to the inside of the dilation processing range 26 based on the dilation processing range information.

[0110] <Example of margin setting screen> As shown in Fig. 13, the inspection device 103 can display a screen for setting a margin. Fig. 13 shows an example of a margin setting screen 50 displayed on the operation unit 133 or the operation unit 102. The margin setting screen 50 may be displayed by a PC.

[0111] The margin setting screen 50 has a mask image display field 43, margin setting buttons 36 (expand button 34, contract button 35), mask release button 38 (select button 39, eraser button 40), setting value 37, decision button 41, and cancel button 42. If the preprint images 11 are different on the front and back, a page back button 44, a current page 46, and a page forward button 45 are displayed.

[0112] The selection button 39 is a button that the user presses when specifying an area from which the user wants to unmask with a mouse or a fingertip (on a touch panel). The eraser button 40 is a button that deletes the area from which the user wants to unmask, which the user specified with the selection button 39.

[0113] The decision button 41 is a button for saving the margin settings (mask image, expansion processing range information, and mask release area information) that have been set on the margin setting screen 50, and for closing the margin setting screen 50. The cancel button 42 is a button for closing the margin setting screen 50 without saving the margin settings.

[0114] The mask image display field 43 visually displays the mask intermediate image. This mask intermediate image will ultimately become the mask image. The margin setting button 36 is a button that allows the user to adjust the degree of expansion or reduction processing (margin width). The margin setting button 36 also displays the current setting value 37. The initial value of the setting value 37 is 0, and 0 indicates no margin. When the user presses the expansion button 34, the setting value 37 increases by one. When the user presses the reduction button 35, the setting value 37 decreases by one.

[0115] Note that a negative value cannot be set for setting value 37. Setting value 37 is managed individually for each area in which a margin is set, so when the user changes the margin setting area, setting value 37 becomes zero once. Setting value 37 until the user changes the margin setting area is stored in memory unit 351.

[0116] The mask intermediate image in the mask image display field 43 is updated in real time each time the margin setting button 36 is pressed. Fig. 13(b) shows a mask intermediate image when the setting value is "2". In Fig. 13(b), the lines are thicker than in Fig. 13(a). If the user presses the reduction button 35 on the mask intermediate image in Fig. 13(b) to return the setting value to "0", the lines will become thinner and the mask intermediate image will return to that of Fig. 13(a).

[0117] 14(a) shows the margin setting screen 50 in which the unmasking area 24 has been set. The user can specify the mask area for which he or she wishes to unmask the area by using the selection button 39. If there is dirt on the preprinted paper, the user can unmask that area.

[0118] When the user presses the selection button 39, he or she can specify a rectangular unmask area 24 using a mouse operation or a fingertip. Next, when the user presses the eraser button 40 and then clicks or taps on the unmask area 24, the frame indicating the unmask area 24 is erased. Thus, the user can cancel the unmask area 24. The unmask area 24 set in this way is saved in the unmask area information as shown in FIG. 8. Multiple unmask areas 24 can be set. The unmask area 24 is not limited to a rectangle, and the user may select a circle or triangle, or draw any shape freehand.

[0119] Once the unmaskable area 24 and margin settings (setting values ​​for each margin setting area) have been determined, the user presses the decision button 41. If the user presses the cancel button 42, the margins are returned to the default state. In addition, all frames indicating the unmaskable area 24 are deleted.

[0120] The user can also increase the margin after specifying the unmasked area 24. In this case, the stain 21 also expands, so the user I / F unit 302 automatically expands the unmasked area 24 by the amount of expansion. FIG. 14(b) shows the unmasked area 24 expanded in accordance with the expansion of the stain 21. In this way, even if the stain portion expands due to an increase in the margin setting value 37, the unmasked area also increases, so it is possible to unmask the stain portion. Conversely, if the user reduces the margin from 2 to 1, for example, the stain portion also shrinks, so the user I / F unit 302 automatically reduces the unmasked area 24 by that amount. The unmasked area information in FIG. 8 is also updated based on the results of this process.

[0121] When the user presses the border type button 32, the user can select the type of border that indicates the unmasked region 24. The type of border can be, for example, a solid line or a dashed dot line. When the user presses the border color button 33, the user can specify the color of the border that indicates the unmasked region 24. The inspection device 103 can change the display to suit the user's preferences and ease of viewing.

[0122] 15 shows the confirmation dialog box 25 that is displayed when the decision button 41 is pressed. The confirmation dialog box is displayed when the decision button 41 for the first page is pressed if the preprinted paper is single-sided, or when the decision buttons 41 for both the first and second pages are pressed if the preprinted paper is double-sided.

[0123] When the user presses the decision button 41, the mask image is stored in the storage unit 305, and the margin setting screen 50 is closed. When the user presses the cancel button 42, the margin setting can be continued.

[0124] Fig. 16 is a diagram for explaining a setting method for setting margins only in the expansion processing range. As explained in Fig. 12, when the user sets margins only in the expansion processing range, the user presses the margin setting range select / cancel button 31. When canceling the margin setting for only the specified area, the user presses the same button again.

[0125] When the user presses the margin setting range select / cancel button 31 once, the margin setting screen 50 enters a range selection state, and the user can specify the rectangular expansion processing range 26 with a mouse or a finger. Since the expansion processing range 26 can be determined by the coordinates of the rectangular area, the mask image generation unit 357 can perform expansion processing only on the expansion processing range 26. The coordinates of the expansion processing range 26 are set in the expansion processing range information in FIG. 7.

[0126] When the margin setting range is selected, the margin setting using the margin setting button 36 applies only to the expansion processing range 26. In Fig. 16(a), the lower part of the mask intermediate image is the expansion processing range 26, so when the margin is set using the margin setting button 36, the margin is set only below the mask intermediate image, as shown in Fig. 16(b).

[0127] When the user presses the margin setting range select / cancel button 31, it becomes possible to set margins for the entire surface of the mask intermediate image.

[0128] The operations using the margin setting range select / cancel button 31 and the mask release button 38 (selection button 39) are mutually exclusive. In other words, if the user presses the mask release button 38 when the margin setting range is selected, the margin setting range selection is released. Conversely, if the user presses the margin setting range select / cancel button 31 when the mask release area 24 is set, the mask release area 24 setting is released.

[0129] Figure 17 is a diagram explaining a method of setting margins by switching between partial margin setting and full margin setting. In Figure 17(a), an expansion processing range 26 (an example of a first expansion processing range) is specified. As shown in Figure 17(b), the user presses the expansion button 34 to increase the margin only in the expansion processing range 26 (an example of a first expansion process).

[0130] Next, as shown in Fig. 17(c), the user releases the margin setting for the expansion processing range 26, switches to the full margin (an example of a second expansion processing range), and increases the margin by one (an example of a second expansion processing). In this case, the margin of the entire surface of the mask intermediate image becomes thicker by one, including the expansion processing range 26 in Fig. 17(b) where the margin setting value is already large. In this way, the user can perform expansion processing partially on the mask intermediate image, so that areas that require a large margin can be expanded separately from areas that do not.

[0131] Next, when the user reduces the margin by one while keeping the full margin (presses the reduction button 35), the margin of the entire surface of the mask intermediate image is reduced by one set value, as shown in FIG. 17(d). In FIG. 17(c), when the user releases the margin setting and sets the margin to the entire surface, the set value 37 of the margin setting button 36 becomes "0". After that, the set value 37 becomes "1" at the end of FIG. 17(c), and becomes "0" in the state of FIG. 17(d), so the user cannot reduce the margin beyond the state of FIG. 17(d). That is, the mask image generating unit 357 reduces the format part of the entire surface that is not included in the expansion processing range 26, with the expansion by the expansion processing performed on the full surface margin as the limit. In this way, the user can manage the margin for each expansion processing range 26 or the entire surface, and it is possible to prevent the expansion of the margin performed in the expansion processing range 26 from being erroneously canceled when the full surface margin is set. To reduce the margin beyond the state of FIG. 17(d), the user needs to select the expansion processing range 26 again.

[0132] <Processing flow> The flow of the above margin setting process will be described in detail below.

[0133] <<Flow of mask image generation by expansion processing>> FIG. 18 is a flowchart illustrating the flow of generating a mask image by the expansion process.

[0134] S001: The printer conveys the pre-printed paper from the paper feed tray to the inspection device 103. The differential image generation unit 309 generates a differential image from the pre-printed image 11 read by the printed image reading unit 307 of the inspection device 103 and the master image 12 with an all-white surface.

[0135] S002: The flag image generation unit 356 binarizes the differential image with a threshold value to generate a flag image 13. The threshold value may be fixed or may be specified by the user.

[0136] S003: The flag image generation unit 356 saves the flag image 13 in the storage units 351 and 305. The flag image 13 in the storage unit 305 is used for the cancellation process described later (leaving the original flag image 13 for cancellation).

[0137] S004: For the flag image 13 saved in the storage unit 351, the mask image generation unit 357 performs margin setting processing. The mask cancellation process may or may not be present, but is described as being present in this embodiment.

[0138] S005: The mask image generation unit 357 saves the mask image for which the margin setting process has been completed in the storage unit 305.

[0139] <<Flow of mask image generation in OR composition processing>> FIG. 19 is a flowchart for explaining in detail the flow of mask image generation in OR composition processing.

[0140] S011: The user sets the number of pre-printed papers to be read. When the number is 1, a flag image 13 as shown in FIG. 9 is generated. When the number is N, as shown in FIG. 10, a flag image 13 obtained by OR-combining the variations for each reading is generated.

[0141] S012: The printer conveys the pre-printed paper from the paper feed tray to the inspection device 103. The differential image generation unit 309 generates a differential image from the pre-printed image 11 read by the printed image reading unit 307 of the inspection device 103 and the master image 12 with an all-white surface.

[0142] S013: The flag image generating unit 356 binarizes the difference image using a threshold value, and generates a plurality of flag images 13. The threshold value may be fixed or may be specified by the user.

[0143] S014: The mask image generating unit 357 performs OR synthesis on the multiple flag images 13 to generate a mask intermediate image.

[0144] S015: If the process has not been completed for the number of sheets read out set in step S011, the process proceeds to step S012; if the process has been completed, the process proceeds to step S016.

[0145] S016: The mask image generation unit 357 stores the intermediate mask image generated in step S014 in the storage units 351 and 305.

[0146] S017: In step S016, the mask image generating unit 357 performs a margin setting process on the mask intermediate image stored in the storage unit 351. The mask release process may or may not be performed, but this embodiment will be described assuming that it is performed.

[0147] S018: The mask image generating unit 357 stores in the storage unit 305 the image obtained by completing the process of step S017 as a mask image.

[0148] <<Details of step S004 or S017>> FIG. 20 is a flow chart illustrating the process of step S004 or S017 in detail.

[0149] S101: On the margin setting screen 50 of FIG. 13 or the like, the user I / F unit 302 draws an intermediate mask image in the mask image display field 43.

[0150] S102: The inspection device 103 waits for the following events. Note that the margin setting range select / cancel button 31 may or may not be present, but in this embodiment it is described as being present. If the margin setting range is not specified, the margin setting process is performed on the entire image. The margin setting button 36 (increase button 34, decrease button 35) was pressed (see Figure 21) The mask release button 38 (selection button 39) was pressed (see Figure 22) The mask release button 38 (eraser button 40) was pressed (see Figure 23) - Margin setting range select / cancel button 31 was pressed (see Fig. 24) - A page switching button (page back button 44, page forward button 45) was pressed (see Figure 25) - The decision button 41 was pressed (see Figure 26) - Cancel button 42 was pressed (see Figure 27) - Border type button 32 was pressed (see Fig. 28) - Border color button 33 was pressed (see Figure 29) FIG. 21 shows a flow chart in which the mask image generating unit 357 changes the expansion level when the margin setting button 36 (expansion button 34, contraction button 35) is pressed.

[0151] S103: When the margin setting button 36 (expansion button 34, reduction button 35) is pressed, the mask image generation unit 357 performs expansion processing on the flag image 13 stored in the memory unit 351 in step S003 of FIG. 18, within a range based on the expansion processing range information of FIG. 7. It is assumed that the expansion processing range information is initialized to coordinates that surround the entire mask intermediate image. However, if the margin determination flag is ON in step S122 described below, no processing is performed and the process returns to waiting for an event. Also, although the expansion processing range information is initialized to coordinates that surround the entire mask intermediate image, the expansion processing range may have been updated in step S115 described below.

[0152] S104: The user I / F unit 302 updates the mask image display field 43 with the intermediate mask image after the expansion process.

[0153] S105: In response to the pressing of the margin setting button 36, the mask image generating unit 357 adjusts the mask release area information to the extent that it exists, and overwrites and saves it in the memory unit 351. Specifically, when the user presses the expand button 34, the mask image generating unit 357 rewrites the information so that the mask release area becomes larger. When the user presses the shrink button 35, the mask image generating unit 357 rewrites the information so that the mask release area becomes smaller. This is because the size of the mask release area 24 increases or decreases depending on the increase or decrease in the margin.

[0154] S106: For the masked intermediate image displayed in the masked image display field 43, the user I / F unit 302 draws a frame representing the unmasked region 24 at the coordinates corresponding to the unmasked region information, and returns to waiting for an event.

[0155] FIG. 22 is a flow chart for explaining the flow when the unmasked region 24 is set.

[0156] S107: When the selection button 39 of the mask release button 38 is pressed, the user I / F unit 302 ends the acceptance of the margin setting range, and the user can now use the mouse to specify the mask release area 24. However, if the margin determination flag is ON in step S122, no processing is performed and the process returns to waiting for an event.

[0157] S108: For example, the mask image generation unit 357 converts the coordinates of the top left and bottom right of the range where the user has left-clicked and dragged into the coordinates of the mask intermediate image, sets these as the unmasked region information of Fig. 8, and saves the unmasked region information in the storage unit 351. The user can specify multiple unmasked regions 24 by repeatedly "dragging while left-clicking."

[0158] S109: The user I / F unit 302 draws a frame representing the unmasked region 24 at the coordinates corresponding to the unmasked region information on the masked intermediate image displayed in the masked image display field 43, and returns to waiting for an event.

[0159] FIG. 23 is a flow chart for explaining the flow of deleting the unmasked region 24. As shown in FIG.

[0160] S110: When the eraser button 40 of the mask release button 38 is pressed, the user I / F unit 302 stops accepting the margin setting range, and the user can specify the mask release area 24 with the mouse or fingertip. However, if the margin determination flag is ON in S122, no processing is performed and the process returns to waiting for an event.

[0161] S111: The user presses the frame or inside the frame of the unmaskable area 24 displayed in the mask image display field 43. The mask image generating unit 357 converts the coordinates of the mouse pointer at that time into coordinates of the mask intermediate image, compares them with the coordinates of the unmaskable area information set in the unmaskable area information in Fig. 8, and deletes the corresponding information.

[0162] S112: The user I / F unit 302 redraws the frame of the unmasked area 24 at the coordinates corresponding to the unmasked area information on the masked intermediate image displayed in the masked image display field 43, thereby causing the frame of the previously selected area to disappear. The process then returns to waiting for an event.

[0163] FIG. 24 is a flow chart for explaining the process when the margin setting range selection / cancellation button 31 is pressed.

[0164] S113: If the mode was in the release mode before the margin setting range selection / release button 31 was pressed (i.e., if the mode was switched from the margin setting mode to the release mode), the process proceeds to step S114. If the mode was not in the release mode (i.e., if the mode was switched from the release mode to the margin setting mode), the process proceeds to step S116. Note that the margin setting range release mode is set when the system is started up.

[0165] S114: The mask image generating unit 357 stops accepting the mask release selection due to the exclusive control, and a rectangular area for the margin setting range can be specified with the mouse or a fingertip.

[0166] S115: For example, the mask image generating unit 357 converts the top left and bottom right coordinates of the range dragged by the user while left-clicking into coordinates of the mask intermediate image, and stores them in the storage unit 351 as expansion processing range information.

[0167] S116: The mask image generating unit 357 initializes the expansion processing range information in FIG. 7 to coordinates that surround the entire mask intermediate image, and stores the information in the storage unit 351.

[0168] S117: The user I / F unit 302 draws a frame representing the expansion processing range at the coordinates corresponding to the expansion processing range information for the mask intermediate image displayed in the mask image display field 43, and returns to waiting for an event.

[0169] FIG. 25 is a flow chart illustrating the page switching process.

[0170] S119: When a page switching button (page back button 44, page forward button 45) is pressed, the user I / F unit 302 saves the currently displayed page in the storage unit 351, reads the mask intermediate image of the front or back page from the storage unit 351, and updates the mask intermediate image displayed in the mask image display field 43. However, in the case of single-sided printing, switching is not possible.

[0171] S120: The user I / F unit 302 performs the same process on the unmasked area information and draws a frame representing the unmasked area 24.

[0172] S121: The user I / F unit 302 performs the same process on the expansion processing range information and draws a frame representing the expansion processing range.

[0173] FIG. 26 is a flow chart illustrating the process when the margin is determined.

[0174] S122: When the decision button 41 on the margin setting screen 50 is pressed, the user I / F unit 302 turns ON the margin decision flag for the displayed page, and the mask image generation unit 357 restricts the margin setting (mask image), mask release area designation, and margin setting range designation for the page with the decision flag ON. The margin decision flags for both sides are saved in the memory unit 351. In the case of single-sided printing, the margin decision flag for the back side is fixed to ON.

[0175] S123: If the double-sided determination flag is ON, the process proceeds to step S124; if not ON, the process returns to waiting for an event.

[0176] S124: The user I / F unit 302 displays the dialog box shown in FIG. 15. If the decision button in FIG. 15 is pressed, the process proceeds to step S125. If the cancel button is pressed, the process proceeds to step S126.

[0177] S125: The mask image generating unit 357 stores the mask image in the storage unit 305 and ends the mask image generating process.

[0178] S126: The mask image generating unit 357 turns off the margin determination flag and returns to waiting for an event. In the case of single-sided printing, the back side determination flag remains ON.

[0179] FIG. 27 is a flow chart for explaining the process when the cancel button 42 is pressed.

[0180] S127: When the cancel button 42 on the margin setting screen 50 is pressed, the user I / F unit 302 turns off the margin determination flag of the displayed page.

[0181] S128: The user I / F unit 302 reads the flag image 13 from the storage unit 305, and places it in the storage unit 351. This flag image 13 is the one saved in step S003 in FIG. 18 or step S016 in FIG.

[0182] S129: The mask image generating unit 357 deletes all unmasked area information of the displayed page.

[0183] S130: The mask image generating unit 357 initializes the expansion processing range information of the displayed page.

[0184] S131: The user I / F unit 302 updates the mask intermediate image in the mask image display field 43 with the flag image 13.

[0185] FIG. 28 is a flowchart showing a process in which the user I / F unit 302 changes the type of frame line.

[0186] S132: When the frame type button 32 is pressed, the user can change the frame type of the unmasked region 24 or the expansion processing range 26. The user can select, for example, a solid line, a dotted line, a dashed line, etc. The frame type may be set differently for the front and back.

[0187] S133: The user I / F unit 302 redraws the frame line in the selected line type and returns to waiting for an event. If the color has been changed in step S134 described below, the frame line is displayed in that color.

[0188] FIG. 29 is a flowchart showing a process in which the user I / F unit 302 changes the color of the frame line.

[0189] S134: When the border color button 33 is pressed, the user can change the border color of the unmasked area. The user can select from, for example, black, red, blue, etc. The border color may be set differently for the front and back.

[0190] S135: The user I / F unit 302 redraws the border in the selected color and returns to waiting for an event. If the border type was changed in step S132, the border is displayed in that line type.

[0191] <Major Effects> The device system of this embodiment can set a margin for the format portion in the mask image, which expands the format portion, so that even if the format portion in the preprinted paper is displaced or distorted due to paper skew, etc., the format portion in the inspection image can be masked, and the format portion can be prevented from being erroneously detected as a defect.

[0192] <Other application examples> The above describes the best mode for carrying out the present invention using examples, but the present invention is not limited to these examples in any way, and various modifications and substitutions can be made within the scope that does not deviate from the gist of the present invention.

[0193] For example, the preprinted paper is not limited to a form consisting of ruled lines and tables, and may have an image printed on it in advance. Fig. 31 is a diagram for explaining a method for generating a mask image 15 from a preprinted paper including an image in a preprint mask generation mode. Note that the explanation of Fig. 31 may mainly focus on the differences from Fig. 9. Two images 261 and 262 are formed in the preprinted image 11 in Fig. 31. Even if the images 261 and 262 are formed in this way, the method for generating the mask image 15 is the same. (1) The difference image generating unit 309 generates a difference image between the preprint image 11 and the master image 12 . (2) The flag image generating unit 356 binarizes the difference image to generate the flag image 13. (3) The mask image generating unit 357 performs an expansion process on the flag image 13 to generate a mask intermediate image 14. In Fig. 31, images 261 and 262 are enlarged for convenience of drawing, but in reality, the expansion process is performed. (4) The mask image generating unit 357 refers to the mask release area information and releases the mask of a specified area in the mask intermediate image 14 to generate a mask image 15.

[0194] 13 and the like may be displayed by a PC or the like, rather than by a display attached to the inspection device 103. In this case, the inspection device 103 acts as a web server and transmits screen information of the margin setting screen 50 described in HTML or the like to the PC. A web browser is executed on the PC, and the margin setting screen 50 is displayed. Note that a native application may be executed on the PC.

[0195] In addition, in this embodiment, inspection device 103 generates difference image 17 between inspection image 64 and master image 65, and then masks difference image 17 using mask image 15. However, inspection device 103 may mask inspection image 64 using mask image 15, and then create difference image 17 using master image 65.

[0196] 4 may be included in the server device. In this case, the inspection device 103 and the server device communicate with each other, the server device transmits the read image data and the like to the server device, and receives the inspection results from the server device. The server device also generates a mask image. The server device functions as a web server and causes a margin setting screen 50 to be displayed on a PC.

[0197] Moreover, the configuration example in Fig. 4 and the like is divided according to main functions in order to facilitate understanding of the processing by the inspection device 103. The present invention is not limited by the manner in which the processing units are divided or the names of the processing units. The processing by the inspection device 103 can be divided into more processing units according to the processing contents. Also, it can be divided so that one processing unit includes more processes.

[0198] Furthermore, the printer 101 does not have to be one that prints by electrophotography, but may be one that prints by inkjet, thermal transfer, letterpress, lithographic, intaglio, stencil, or other methods.

[0199] Furthermore, the printing system 100 is not limited to being used for commercial printing, but may also be used in offices, factories, ordinary homes, convenience stores, and the like.

[0200] Furthermore, the processing of the inspection device 103 described in this embodiment may be executed by a server device connected via a network. In the preprint mask generation mode, the inspection device 103 transmits margin settings and a preprint image to the server device, and the server device creates a mask image. In the actual printing detection mode, the inspection device 103 transmits an inspection image and print data to the server device, and the server device generates a difference image, performs mask processing with the mask image, and transmits the inspection results to the inspection device 103.

[0201] Each function of the above-described embodiments can be realized by one or more processing circuits. Here, the term "processing circuit" in this specification includes a processor programmed to execute each function by software, such as a processor implemented by an electronic circuit, and a device such as an ASIC (Application Specific Integrated Circuit), a DSP (Digital Signal Processor), an FPGA (Field Programmable Gate Array), or a conventional circuit module designed to execute each function described above.

[0202] <Additional Notes> [Claim 1] An inspection device for inspecting a printed matter in which print data is printed on a print medium on which a preprinted portion has been printed in advance, comprising: a print image reading unit that reads the print medium and generates first image data; a mask image generating unit that generates a mask image by enlarging the preprint portion in the first image data; a differential image generating unit that generates a differential image between second image data generated by the print image reading unit by reading the print and a master image generated from the print data; a mask processing unit that performs a mask processing on the difference image using the mask image; a defect determination processing unit that determines whether or not the printed matter has a defect based on the differential image that has been subjected to the mask processing; An inspection device having the above structure. [Claim 2] 2. The inspection device according to claim 1, wherein the mask image generating unit enlarges the preprint portion by performing an expansion process on the preprint portion in the first image data. [Claim 3] 2. The inspection device according to claim 1, wherein the mask image generating unit enlarges the preprint portion by combining a plurality of the first image data generated by reading a plurality of the printing media. [Claim 4] a user I / F unit that displays a screen including the first image data and accepts designation of an expansion processing range in the first image data for which the expansion processing is to be performed; The inspection device according to claim 2 , wherein the mask image generating unit performs the expansion process only on an expansion process range. [Claim 5] the screen has an inflation button for receiving inflation; the mask image generating unit repeats the expansion process each time the expansion button is pressed; 5. The inspection device according to claim 4, wherein the user I / F unit updates the first image data every time the expansion process is performed. [Claim 6] the screen has a reduction button for accepting a reduction process for the preprint portion in the first image data, the mask image generating unit repeats the reduction process each time the reduction button is pressed; 6. The inspection apparatus according to claim 5, wherein the user I / F unit updates the first image data every time the reduction process is performed. [Claim 7] When a first expansion processing range is subjected to a first expansion processing and then a second expansion processing range including the first expansion processing range is designated, the mask image generating unit performs a second expansion process in addition to the first expansion process for an area where the first expansion process range and the second expansion process range overlap; The inspection device described in claim 6, wherein a second expansion processing is performed on the preprint portion on which the first expansion processing has not been performed, for an area of ​​the second expansion processing range that does not include the first expansion processing range. [Claim 8] When the reduction button is pressed after the second expansion process is performed, 8. The inspection device according to claim 7, wherein the mask image generating section reduces the preprint portion in the second expansion processing range up to an extent equal to the amount of expansion by the second expansion processing. [Claim 9] the user I / F unit accepts designation of a mask release area for releasing the mask process on a screen including the first image data; 9. The inspection device according to claim 5, wherein the mask processing unit performs mask processing on the difference image by using the mask image, excluding the unmasked region. [Claim 10] the user I / F unit displays a frame indicating the mask release area, 10. The inspection device according to claim 9, wherein, when the expansion button is pressed, the mask image generation section expands the frame. [Claim 11] 2. The inspection device according to claim 1, wherein the preprinted portion is a ruled line forming a table. [Explanation of symbols]

[0203] 100 Printing System 101 Printer 103 Inspection Equipment 104 Stacker [Prior art documents] [Patent documents]

[0204] [Patent Document 1] Patent No. 4127326< / dfe>

Claims

1. An inspection device for inspecting a printed matter in which print data is printed on a print medium on which a preprinted portion has been printed in advance, comprising: a print image reading unit that reads the print medium and generates first image data; a mask image generating unit that generates a mask image by enlarging the preprint portion in the first image data; a differential image generating unit that generates a differential image between second image data generated by the print image reading unit by reading the print and a master image generated from the print data; a mask processing unit that performs a mask processing on the difference image using the mask image; a defect determination processing unit that determines whether or not the printed matter has a defect based on the differential image that has been subjected to the mask processing; An inspection device having the above structure.

2. The inspection device according to claim 1 , wherein the mask image generating section enlarges the preprint portion by performing an expansion process on the preprint portion in the first image data.

3. The inspection device according to claim 1 , wherein the mask image generating unit enlarges the preprint portion by combining a plurality of the first image data generated by reading a plurality of the print media.

4. a user I / F unit that displays a screen including the first image data and accepts designation of an expansion processing range in the first image data for which the expansion processing is to be performed; The inspection apparatus according to claim 2 , wherein the mask image generating section performs the expansion processing only on an expansion processing range.

5. the screen has an inflation button for receiving inflation; the mask image generating unit repeats the expansion process each time the expansion button is pressed; The inspection apparatus according to claim 4 , wherein the user I / F unit updates the first image data each time the expansion process is performed.

6. the screen has a reduction button for accepting a reduction process for the preprint portion in the first image data, the mask image generating unit repeats the reduction process each time the reduction button is pressed; The inspection apparatus according to claim 5 , wherein the user I / F unit updates the first image data every time the reduction process is performed.

7. When a first expansion processing range is subjected to a first expansion processing and then a second expansion processing range including the first expansion processing range is designated, the mask image generating unit performs a second expansion process in addition to the first expansion process for an area where the first expansion process range and the second expansion process range overlap; An inspection device as described in claim 6, wherein for areas of the second expansion processing range that do not include the first expansion processing range, a second expansion processing is performed on the preprint portion that has not been subjected to the first expansion processing.

8. When the reduction button is pressed after the second expansion process is performed, The inspection device according to claim 7 , wherein the mask image generating section reduces the preprint portion in the second expansion processing range up to an extent equal to the amount of expansion by the second expansion processing.

9. the user I / F unit accepts designation of a mask release area for releasing the mask process on a screen including the first image data; 9. The inspection apparatus according to claim 5, wherein the mask processing unit performs mask processing on the difference image using the mask image, excluding the unmasked region.

10. The user I / F unit displays a frame indicating the mask release area, The inspection device according to claim 9 , wherein the mask image generating unit expands the frame when the expansion button is pressed.

11. The inspection device according to claim 1 , wherein the preprinted portion is a ruled line or an image forming a table that is printed in advance on the printing medium.

12. An inspection method in which an inspection device inspects a printed matter in which print data is printed on a print medium on which a preprinted portion has been printed, the method comprising: A process of reading the print medium and generating first image data; generating a mask image by enlarging the preprint portion in the first image data; A process of generating a difference image between second image data generated by reading the printed matter and a master image generated from the print data; performing a masking process on the difference image using the mask image; and determining whether or not the print has a defect based on the difference image that has been subjected to the mask processing; An inspection method having the following features.

13. A program for causing a computer to function as the inspection device according to claim 1.

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