Printed matter inspection device, printed matter inspection method, and program

Abstract

To provide a system for inspecting a printed matter that can set a proper inspection level while taking an account of a printing condition such as sheet properties.SOLUTION: A device for inspecting a printed matter determines a range in which an inspection level (sensitivity in inspecting defects) can be set in the parameters for inspecting a defect of a printed matter according to a sheet type or the like that is a printing condition of a printed matter.SELECTED DRAWING: Figure 6

Description

[Technical Field]

[0001] The technology of the present disclosure relates to a technology for inspecting printed matter. [Background technology]

[0002] Conventionally, inspection systems have been used that automatically inspect the quality of printed matter and, based on the inspection results, reprint or sort acceptable and unacceptable products. For such inspection systems, the criteria for determining whether or not a printed matter has defects are important, and Patent Document 1 discloses a method for setting inspection parameters that serve as the criteria depending on the environment in which the printed matter is used. Specifically, the technology discloses a technique that acquires the distance (observation distance) at which the printed matter is viewed as usage environment information, and, if the distance is long, lowers the defect detection level (inspection level) or reduces the number of types. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Publication No. 2020-94891 Summary of the Invention [Problem to be solved by the invention]

[0004] In the technology of Patent Document 1, a high inspection level is set when the print is observed from a short distance. However, if the recording medium (paper) used for printing contains foreign matter (impurities) or is soiled, this will be detected as a defect even if there is no problem with the printing process itself. As a result, a greater number of rejected products than expected will be generated. This requires the user to reset the inspection level according to the characteristics of the paper being used, significantly reducing usability.

[0005] The technology disclosed herein has been made in consideration of the above-mentioned problems, and aims to provide an inspection system for printed matter that can set an appropriate inspection level taking into account printing conditions such as paper characteristics. [Means for solving the problem]

[0006] The inspection device according to the present disclosure includes a control means for controlling a settable range of an inspection level for inspecting a printed matter based on printing conditions of the printed matter, a setting means for setting the inspection level, and an inspection means for performing a process for detecting defects from a read image obtained by reading the printed matter based on the set inspection level. the control means determines a plurality of level values ​​that can be set as the inspection level based on the printing conditions, displays the determined level values ​​on the display means in a manner that allows the user to select the level, accepts a selection operation from the user, and displays a warning on the display means if it is predicted that the reject rate will exceed a threshold value when the inspection level related to the accepted selection operation from the user is applied. It is characterized by: [Effects of the Invention]

[0007] According to the technology of the present disclosure, it is possible to provide an inspection system for printed matter that can set an appropriate inspection level taking into account printing conditions such as paper characteristics. [Brief explanation of the drawings]

[0008] [Figure 1] FIG. 1 is a diagram showing an example of the configuration of a printing system. [Figure 2] FIG. 2 is a diagram showing the hardware configuration of a printing module. [Figure 3] FIG. 2 is a diagram showing the hardware of the inspection module. [Figure 4] FIG. 2 is a block diagram showing the main functional configuration of an inspection module. [Figure 5] 10 is an example of a list associating paper types with inspection levels. [Figure 6] 10 is a flowchart showing a specific flow of an inspection parameter setting process. [Figure 7] FIG. 10 is a diagram showing an initial state of an inspection parameter setting screen. [Figure 8] (a) is an example of an inspection parameter setting screen in which the display has been changed so that only inspection levels compatible with plain paper can be selected, and (b) is an example of an inspection parameter setting screen in which the display has been changed so that only inspection levels compatible with coated paper can be selected. [Figure 9]An example of predicted waste rate for plain paper. [Figure 10] An example of a warning message when the predicted waste rate is about to be exceeded. [Figure 11] (a) and (b) are examples of the inspection parameter setting screen showing the predicted paper waste rate. DETAILED DESCRIPTION OF THE INVENTION

[0009] Hereinafter, embodiments of the present invention will be described with reference to the accompanying drawings. However, the components described in these embodiments are merely examples and are not intended to limit the scope of the present invention.

[0010] [Embodiment 1] 1 is a diagram showing an example of the configuration of a printing system according to this embodiment. In the printing system, an image forming apparatus 100 having an inspection function is communicably connected to a client PC 130 and a print server 140 via a network 120. The image forming apparatus 100 also includes a printing module 111, an inspection module 112, and a finisher 113.

[0011] The print module 111 is a module that prints out print data sent from the client PC 130 or the print server 140. The print module 111 also functions as a main module that controls the entire image forming apparatus 100.

[0012] The inspection module 112 is a module that inspects whether or not there are defects in the printed matter output from the printing module 111. Here, defects refer to things that occur during the printing process that reduce the quality of the printed matter, such as stains caused by coloring material adhering to unintended locations, or color loss caused by insufficient coloring material adhering to intended locations.

[0013] The finisher 113 is a module that performs post-processing (such as bookbinding) as necessary on the printed matter inspected by the inspection module 112, and ejects the paper to an ejection destination according to the inspection result.

[0014] The printing module 111, inspection module 112, and finisher 113 are connected to each other via communication cables, and the image forming apparatus 100 can perform printing, inspection, post-processing, and paper discharge in an integrated manner. Note that the printing module 111, inspection module 112, and finisher 113 that make up the image forming apparatus 100 may each be an independent device.

[0015] <Internal structure of the printing module> 2 is a diagram showing the internal configuration of the print module 111. The print module 111 has a printer controller 200, a printer engine 210, and a UI unit 220. The printer controller 200 is a controller that controls the entire print module 111. The printer engine 210 is a printer engine that forms an image on paper using a predetermined printing method such as electrophotography or inkjet printing. The UI unit 220 is an interface that allows the user to set printing conditions and is composed of a touch panel display or the like.

[0016] First, a description will be given of the printer controller 200. The printer controller 200 includes a network I / F 201, a CPU 202, a RAM 203, a ROM 204, an image processing unit 205, an engine I / F 206, a communication I / F 207, and a system bus 208.

[0017] The network I / F 201 is an interface for sending and receiving data to and from the client PC 130 and the print server 140 via the network 120. The CPU 202 is an arithmetic processing unit that controls the entire print module 111. The RAM 203 is a volatile memory that serves as a work area when the CPU 202 executes various commands, and the ROM 204 is a non-volatile memory that stores data such as programs executed by the CPU 202 at startup and various setting values. The image processing unit 205 performs predetermined image processing on image data to be printed that is received from the network 120, and generates print data that can be processed by the printer engine 210. The engine I / F 206 is an interface for passing the print data generated by the image processing unit 205 to the printer engine 210. The communication I / F 207 is an interface for communicating with the inspection module 112 and the finisher 113. The system bus 208 is an internal bus that connects the above-mentioned components in the print module 111 to each other.

[0018] When a user prints a document created using a document application or the like, the user converts image data of the document or the like into PDL data format using the client PC 130 or the print server 140 and sends the PDL data to the image forming apparatus 100. Upon receiving the PDL data, the image forming apparatus 100 stores it in RAM 203. Information on printing conditions, such as paper type and paper size, specified by the user via the UI unit 220 is also stored in RAM 203. The CPU 202 then issues a print instruction to the printer engine 210 based on the printing conditions stored in RAM 203. For example, if coated paper is specified as the paper type in the printing conditions, the CPU 202 instructs the printer engine 210 to feed paper from a paper cassette (not shown) that stores coated paper. The image processing unit 205 acquires the PDL data stored in RAM 203, performs predetermined image processing, and converts it into print data. This image processing includes rasterization, which analyzes the PDL to generate multi-level bitmap data, and screen processing, which converts multi-level bitmap data into binary bitmap data. The binary bitmap data obtained by image processing is sent to the printer engine 210 via the engine I / F 206. Then, the printer engine 210 forms an image on paper using color materials based on the binary bitmap data provided by the printer controller 200.

[0019] As described above, various processes from receiving the PDL data to printing it on paper are controlled by the CPU 202, so that a full-color image is formed on the specified paper, and the resulting printout is output to the inspection module 112. Note that the recording medium is not limited to paper, and may be a plastic sheet, a metal sheet, or the like.

[0020] <Internal structure of the inspection module> FIG. 3 is a diagram showing the internal configuration of the inspection module 112. The inspection module 112 includes an inspection controller 300, an image reading unit 310, and a UI unit 320. The inspection controller 300 is a controller that controls the entire inspection module 112. The image reading unit 310 acquires a read image (inspection image) to be inspected by, for example, taking a photograph of the printed paper output from the print module 111 using a camera (not shown). The UI unit 320 is configured with a touch panel display or the like, and provides a user interface that enables the user to set inspection conditions such as paper type and inspection level prior to the inspection process and to check the inspection results. The inspection level can be set in stages by providing multiple level values, for example, from 1 to 6. In this embodiment, the level values ​​are associated with the detection content so that the higher the level value, the higher the inspection sensitivity (i.e., so that finer defects can be detected).

[0021] The inspection controller 300 has a communication I / F 301, a CPU 302, RAM 303, ROM 304, and a system bus 305. The communication I / F 301 is an interface for data communication with the print module 111 and the finisher 113. The CPU 302 is an arithmetic processing unit that controls the entire inspection module 112. The RAM 303 is a volatile memory that serves as a work area when the CPU 302 executes various commands, and the ROM 304 is a non-volatile memory that stores programs executed by the CPU 302 at startup and data such as various setting values. The system bus 305 is an internal bus that interconnects the above-mentioned components within the inspection module 112.

[0022] The UI unit 320 is an interface that allows the user to set the inspection level and check the inspection results, and is configured with a touch panel display or the like.

[0023] <Inspection module functional configuration> 4 is a block diagram showing the main functional configuration of the inspection module 112. The inspection module 112 comprises an inspection parameter DB 400, a UI control unit 401, a parameter setting unit 402, and an inspection processing unit 403.

[0024] The inspection parameter DB 400 is a database that stores inspection parameter information, such as various printing conditions, such as the type and size of paper usable during printing (paper type, paper size), paper transport speed, and available inspection levels. In particular, in this embodiment, a list is stored that associates paper types with the availability of inspection level settings for each level value. Coated paper often contains smaller and fewer impurities than plain paper, and is often used for high-quality prints. Therefore, when printing using coated paper, the user is permitted to set a high inspection level. On the other hand, when printing using plain paper, it is anticipated that a certain number of impurities larger than a certain size will be present. Therefore, the user is prevented from setting a high inspection level that would result in such impurities being detected as print defects. Note that in the case of coated paper, a too low inspection level can result in long inspection times. Therefore, it is desirable to prevent the user from setting a low inspection level for coated paper. Based on this premise, a list such as that shown in FIG. 5 is created and stored. In the list of Figure 5, six levels of inspection sensitivity are provided, from 1 to 6, in order of decreasing sensitivity. For both plain paper and coated paper, the level values ​​that the user can use (can be set) are marked with "OK," and the level values ​​that the user cannot use (cannot be set) are marked with "NO." The list data that is actually stored is held in a data structure in which a flag value of "1" is assigned to "OK" to indicate that it is valid, and a flag value of "0" is assigned to "NO" to indicate that it is invalid.

[0025] The UI control unit 401 performs control processing such as displaying various user interface screens (UI screens) on the UI unit 320 for the user to perform various operations and give instructions, and changing the display contents of the UI screens.

[0026] The parameter setting unit 402 sets the inspection parameters to be actually applied in the inspection process based on the user's selection operation via a predetermined UI screen. The process of setting the inspection parameters will be described in detail later.

[0027] The inspection processing unit 403 executes inspection processing in accordance with the inspection parameters set by the parameter setting unit 402 .

[0028] <Inspection module operation overview> Next, we will explain the outline of the operation related to the inspection of printed matter in the inspection module 112. In the inspection module 112, first, an inspection parameter setting process is performed as a preparatory process, specifically, a process of setting the paper type and inspection level. In this embodiment, we will explain an example of controlling the UI screen for setting the inspection parameters so that an appropriate inspection level is set in consideration of the characteristics of the paper used in the printing process in this inspection parameter setting process.

[0029] After the preparation process is complete, the print to be inspected, conveyed from the printing module 111, is scanned by the image reader 310, and an inspection image is acquired. The acquired inspection image is stored in RAM 303. An image (difference image) is then generated, showing the difference between a previously prepared reference image and the inspection image obtained by scanning the print. In both the reference image and the inspection image, each pixel has, for example, an 8-bit RGB value (0 to 255). The difference image is an image in which the difference values ​​between corresponding pixels for each RGB channel are calculated and then averaged to form a single channel. Each pixel value of the generated difference image is then inspected for print defects according to the inspection level set in the preparation process. The inspection results are stored in RAM 303, and the presence or absence of print defects and the type of print defects are displayed on the UI unit 320, allowing the user to recognize the inspection results. Furthermore, if a certain number of prints with print defects occur consecutively, the inspection module 112 notifies the printing module 111 of this fact. Upon receiving this notification, the printing module 111 stops printing. Furthermore, the inspection module 112 notifies the print module 111 of the inspection results as needed, and under control via the print module 111, the finisher 113 ejects the printouts that have been inspected to a predetermined output destination.

[0030] <Inspection parameter setting process> Fig. 6 is a flowchart showing a specific flow of inspection parameter setting processing by the parameter setting unit 402 according to this embodiment. The series of processing shown in the flowchart in Fig. 6 is realized by the CPU 302 executing a predetermined program. In the following explanation, the symbol "S" means step.

[0031] First, in S601, a user interface screen for setting inspection parameters (hereinafter referred to as the "inspection parameter setting screen") is displayed on the UI unit 320 in response to a predetermined user operation. FIG. 7 is a diagram showing the initial state of the inspection parameter setting screen according to this embodiment. The initial screen 700 shown in FIG. 7 includes a pull-down menu 701 for selecting a paper type and check boxes 702a to 702f corresponding to six levels of inspection. Also included are a "Confirm" button 703 for confirming the user's selection and a "Cancel" button 704 for canceling the input. Below each check box, an illustration of the size of a defect detectable at each inspection level is displayed. Here, a granular defect is used as an example of a defect to be detected, and its diameter is shown as its size, but this is not limiting. For example, in the case of a streak-like defect, the detectable size of the streak according to the level value (e.g., 0.05 mm to 0.2 mm for width and 0.4 mm to 0.6 mm for length) could be displayed with an illustration. Furthermore, gray patches with different density values ​​(RGB values) may be displayed for each level value of the inspection level, so that the density of detectable defects can also be specified in association with the level value.

[0032] S602 is a process for monitoring a user's selection operation regarding a paper type. For example, if an operation of hovering the mouse over a desired paper type from among the multiple paper types displayed in the pull-down menu 701 and clicking is detected, the process proceeds to S603.

[0033] In S603, the paper type designated by the user is set based on the selection operation regarding the paper type detected in S602.

[0034] In the next step S604, the display of the inspection level values ​​on the inspection parameter setting screen is changed so that only level values ​​that correspond to the paper type set in step S603 can be selected by the user. At this time, the level values ​​that correspond to the set paper type are identified by referring to the list in FIG. 5 described above. FIG. 8(a) shows the inspection parameter setting screen displayed when the paper type is set to "plain paper," in which only level values ​​that correspond to plain paper can be selected. In the inspection parameter setting screen 800 shown in FIG. 8(a), the relatively high inspection levels 4 to 6 are grayed out to prevent the user from selecting them, prompting the user to select from the remaining range of levels 1 to 3. Also, FIG. 8(b) shows the inspection parameter setting screen displayed when the paper type is set to "coated paper," in which only level values ​​that correspond to coated paper can be selected. In the inspection parameter setting screen 810 shown in FIG. 8(b), the level values ​​1 and 2 are grayed out to prevent the user from selecting them, prompting the user to select from the remaining range of levels 3 to 6. Note that as long as the user can recognize the level values ​​of the inspection levels that can be selected by the user and that correspond to the set paper type, it is possible to, for example, display selectable level values ​​in different colors or with different line thicknesses. Alternatively, a message informing the user of the selectable (or non-selectable) level values ​​may be displayed on the screen. Furthermore, it is possible to ensure as wide a range of level value options as possible for the paper type specified by the user. For example, as in the following change patterns 1 and 2, changes may be made to include lower sensitivity level values ​​in the options, or to narrow the intervals between level values ​​to limit the number of selectable level values ​​to a certain number or more.

[0035] <Change Pattern 1> Level 1: Changed from 0.35mm to 0.50mm Level 2: Changed from 0.30mm to 0.45mm Level 3: Changed from 0.25mm to 0.40mm Level 4: Changed from 0.20mm to 0.35mm Level 5: Changed from 0.15mm to 0.30mm Level 6: Changed from 0.10mm to 0.25mm <Change Pattern 2> Level 1: Maintains 0.35mm display Level 2: Changed from 0.30mm to 0.325mm Level 3: Changed from 0.25mm to 0.30mm Level 4: Changed from 0.20mm to 0.275mm Level 5: Changed from 0.15mm to 0.25mm Level 6: 0.10mm display grayed out

[0036] In S605, a process of monitoring a selection operation by the user regarding the inspection level is performed. For example, if it is detected that any of the above-mentioned check boxes 702a to 702f has been checked, the process proceeds to S606.

[0037] In S606, a level value designated by the user is set based on the selection operation regarding the inspection level detected in S605.

[0038] S607 is a process of monitoring whether the user has selected the "OK" button 703 or the "Cancel" button 704. If pressing of the "OK" button 703 is detected, the process proceeds to S608. On the other hand, if pressing of the "Cancel" button 704 is detected, the process ends.

[0039] In S608, the paper type determined in S603 and the level value of the inspection level determined in S606 are determined as inspection parameters to be applied to the inspection process.

[0040] The above is the content of the inspection parameter setting process according to this embodiment.

[0041] <Variation 1> Furthermore, information on the predicted reject rate (also referred to as the "predicted paper waste rate") corresponding to the level value of the inspection level may be linked to the paper type and stored in the inspection parameter DB 101. This information may be used to prompt the user to set an appropriate inspection level. Here, the predicted paper waste rate can be defined as the probability of occurrence of rejects depending on the size of impurities contained in the paper. FIG. 9 shows an example of information on the predicted paper waste rate for plain paper summarized in a graph format. The user checks such predicted paper waste rates for each paper type in advance and stores them in the inspection parameter DB 101. A predetermined threshold (e.g., 20%) is then set in advance, and when the predicted paper waste rate at the level value selected by the user exceeds the threshold, a warning message 1001 is displayed, for example, as shown in FIG. 10. The warning message may be displayed when a checkbox is checked, as shown in FIG. 10, or when the mouse hovers over the display area for each level value.

[0042] Furthermore, as shown in FIG. 11(a) or (b), the predicted paper waste rate may be displayed in association with each level value according to the selected paper type.

[0043] Furthermore, the larger the paper size, the greater the degree to which the paper is deformed during the printing process, which can lead to overdetection of defects and a higher-than-expected rate of paper waste. Therefore, if a paper size larger than a certain size (e.g., A3) is set as the paper size to be used, the higher inspection levels may be grayed out so that they cannot be selected, or a warning message may be displayed when a high inspection level is selected.

[0044] In this way, when a user attempts to select an inspection level value, the predicted paper waste rate for the paper type being set is presented to the user, allowing the user to set an appropriate inspection level taking the paper waste rate into consideration.

[0045] <Variation 2> In the above-described embodiment, the level value of the inspection level that the user can select is controlled according to the set paper type, but the level value that the user can select may also be controlled based on printing conditions other than paper type.

[0046] For example, if the set paper transport speed is high, the inspection must be completed in a short time. Therefore, if the processing time required for the inspection increases or decreases depending on the inspection level (if there is a correlation), control may be performed so that only the inspection level that matches the processing time can be selected. Note that this modified example can also be applied when the paper transport speed is indirectly determined depending on the print quality.

[0047] For example, if the set paper type is thin paper, offset is likely to occur. As a result, the possibility of overdetecting defects increases. Therefore, if thin paper is set, it may be possible to make it impossible to select high inspection levels.

[0048] As described above, according to this embodiment, it is possible to set an appropriate inspection level taking into account the characteristics of the recording medium and the like.

[0049] (Other Examples) The technology of the present disclosure can also be realized by supplying a program that realizes one or more functions of the above-described embodiments to a system or device via a network or a storage medium, and having one or more processors in the computer of the system or device read and execute the program. It can also be realized by a circuit (e.g., ASIC) that realizes one or more functions.

Claims

1. a control means for controlling a settable range of an inspection level for inspecting the printed matter based on the printing conditions of the printed matter; a setting means for setting the inspection level; an inspection means for performing a process of detecting defects from a read image obtained by reading the printed matter based on the set inspection level; Equipped with The control means determining a plurality of level values ​​that can be set as the inspection level based on the printing conditions, and displaying the determined level values ​​on a display means in a manner that allows a user to select the level; accepting a selection operation by the user; If the reject rate is expected to exceed a threshold when the inspection level selected by the user is applied, a warning is displayed on the display means. An inspection device characterized by:

2. 2. The inspection apparatus according to claim 1, wherein the control means further displays, on the display means, information about defects detectable at each level value, for each level value that can be selected as an inspection level option.

3. 3. The inspection apparatus according to claim 2, wherein the information about the detectable defect is information indicating the size of the defect.

4. 3. The inspection apparatus according to claim 2, wherein the information about the detectable defect is information representing the density of the defect.

5. 5. The inspection apparatus according to claim 3, wherein the defect is a granular defect or a streak defect.

6. a storage unit for storing parameter information that associates the printing conditions with whether or not each level value of the inspection level can be set, the control means displays, on the display means, level values ​​that can be set under the printing conditions designated by the user among the level values ​​of the inspection levels based on the parameter information, in a manner that can be selected by the user.

2. The inspection device according to claim 1.

7. 7. The inspection device according to claim 6, wherein the control means displays, on the display means, level values ​​of the inspection levels that cannot be set under the printing conditions specified by the user, in a manner that makes them unselectable by the user, based on the parameter information.

8. The inspection device according to any one of claims 2 to 5, characterized in that the control means changes and displays information regarding the detectable defects for each level value so that the number of level values ​​selectable under the printing conditions specified by the user is equal to or greater than a certain number.

9. the printing conditions are the type of recording medium used in the printing process of the printed matter; a settable range of the inspection level is determined according to the type; 9. The inspection device according to claim 1, wherein the inspection device is a semiconductor laser.

10. the printing conditions are the size of a recording medium used in the printing process of the printed matter, The larger the size, the lower the sensitivity corresponding to the settable range of the inspection level is determined to be.

9. The inspection device according to claim 1, wherein the inspection device is a semiconductor laser.

11. the printing condition is a thickness of a recording medium used in the printing process of the printed matter, The thinner the thickness, the lower the sensitivity corresponding to the settable range of the inspection level is determined to be.

9. The inspection device according to claim 1, wherein the inspection device is a semiconductor laser.

12. the printing condition is a conveyance speed of a recording medium in a printing process of the printed matter; a settable range of the inspection level is determined according to the conveying speed; 9. The inspection device according to claim 1, wherein the inspection device is a semiconductor laser.

13. 2. The inspection device according to claim 1, wherein the control means further displays, on the display means, an expected reject rate for each level value that can be selected as an inspection level option for a user's selection operation.

14. a control step of controlling a settable range of an inspection level for inspecting the printed matter based on printing conditions of the printed matter; a setting step of setting the inspection level; an inspection step of performing a process of detecting defects from a read image obtained by reading the printed matter based on the set inspection level; and In the control step, determining a plurality of level values ​​that can be set as the inspection level based on the printing conditions, and displaying the determined level values ​​on a display means in a manner that allows a user to select the level; accepting a selection operation by the user; displaying a warning on the display means when it is predicted that the reject rate will exceed a threshold when the inspection level related to the received user selection operation is applied; An inspection method characterized by:

15. A program for causing a computer to function as the inspection device according to any one of claims 1 to 13.

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