Image inspection system, image inspection device, and inspection level setting support method

Abstract

Set the inspection level appropriately. [Solution] The image inspection system 100 transports the printed material fed from the paper feed unit 21, which already has content printed on the paper, to the transport path, and with the printing operation of the image forming unit turned OFF, it has an inspection level setting support mode in which it detects image defects based on the first read image obtained by reading the printed material with the image reading unit 25, thereby setting an inspection level threshold.

Description

Technical Field

[0001] The present invention relates to an image inspection system, an image inspection apparatus, and an inspection level setting support method.

Background Art

[0002] Conventionally, there has been an inspection technique for inspecting an image by reading an image formed on a recording material such as paper by an image forming apparatus with a reading apparatus installed in the image forming apparatus and reading the image on the conveyed paper, and comparing this with a reference image.

[0003] In the image inspection system disclosed in Patent Document 1, an image with a pseudo defect added is output for an input image. And a technique has been proposed for determining a threshold value for determining a defect in a read image based on a difference between a defect read image obtained by reading the output result and a master image serving as a reference generated from the input image.

Prior Art Documents

Patent Documents

[0004]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0005] However, in the inspection technique disclosed in Patent Document 1, for input image data, an image simulating pseudo - generated dirt or toner adhesion in a streak shape is image - processed and printed. Therefore, the characteristics such as appearance and impression are somewhat different from those of actual defects, and in the printed chart for threshold setting, there is a possibility that actual image defects are not sufficiently reflected. The present invention has been made in view of the above circumstances, and an object thereof is to appropriately set an inspection level by setting a threshold value of the inspection level using a printed matter in which a defect has actually occurred. [Means for solving the problem]

[0006] The above objectives of the present invention are achieved by the following means.

[0007] (1) Paper feeding section and An image forming unit that forms an image on paper fed from the aforementioned paper feeding unit and transported, The system includes an image reading unit, which is located downstream of the image forming unit on the transport path through which the paper is transported, and reads the image on the paper. An image inspection system that uses a read image generated by the reading of the image reading unit to detect image defects using a set inspection level threshold, An image inspection system having an inspection level setting support mode that transports printed materials fed from a paper feed unit, which already has content printed on the paper, to the transport path, and, with the printing operation of the image forming unit turned OFF, detects image defects based on a first read image obtained by reading the printed materials with the image reading unit, thereby setting a threshold for the inspection level.

[0008] (2) The image inspection system described in (1) above, wherein the content is user content containing image defects, not a test chart.

[0009] (3) Using the RIP image of the user content as the reference image, The image inspection system according to (2) above, wherein the first read image is used as an inspection image, and image defects are detected by comparative inspection between the inspection image and the reference image.

[0010] (4) Among the printed materials obtained by printing the RIP image of the user content in the image forming unit, A printed document without image defects is used as the correct paper sample. The correct paper sample is fed and transported from the paper feed unit where the correct paper sample is set. With the printing operation of the image forming unit turned OFF, the correct paper sample is read by the image reading unit, and the second read image obtained is used as the reference image. The image inspection system according to (2) above, wherein the first read image is used as an inspection image, and image defects are detected by comparative inspection between the inspection image and the reference image.

[0011] (5) Multiple test levels with different thresholds are pre-set, and multiple test results for each of the multiple test levels are presented to the user. The image inspection system described in (3) or (4) above, which registers the inspection level used in the inspection result selected by the user from among the presented inspection results as a preset value to be used for inspection.

[0012] (6) The image inspection system described in (5) above, wherein for one type of image defect, there are multiple setting items, and for each setting item, multiple inspection levels are pre-set, and the inspection is performed using a combination of the inspection levels of the multiple setting items, and the inspection results of the combination of the inspection levels of the multiple setting items are presented to the user.

[0013] (7) The image inspection system described in (6) above, wherein the presentation to the user is a display on the display unit.

[0014] (8) The image inspection system described in (6) above, wherein the output to the user is the inspection result report.

[0015] (9) A reference image generated based on the RIP image of the print data of the print job, The image inspection system according to (5) above, which performs a normal image inspection mode, wherein the RIP image is printed by the image forming unit, the printed material is read by the image reading unit, the read image obtained is used as the inspection image, and image defects are detected by comparison inspection with the inspection image.

[0016] (10) The image inspection system according to (9) above, wherein the processing time of the inspection level setting support mode is longer than the maximum processing time allowed in the normal image inspection mode.

[0017] (11) The image forming unit is an inkjet type image forming unit that forms an image by ejecting ink from nozzles of a head module onto a sheet, and the image inspection system according to (1) above.

[0018] (12) When executing the inspection level setting support mode, the image forming unit moves the carriage on which the head module is installed to a retracted position where it is retracted to a position not facing the sheet, and the image inspection system according to (11) above.

[0019] (13) An image inspection apparatus that is disposed downstream of the image forming unit on a conveyance path along which a sheet is conveyed, and detects an image defect using a set inspection level threshold value with a read image generated by reading an image on the sheet by an image reading unit, feeding and conveying the printed matter from a paper feeding unit on which a printed matter printed with user content including an image defect and not a test chart is set, and in a state where the printing operation of the image forming unit is turned off, detecting an image defect based on a first read image obtained by reading the printed matter by the image reading unit, and having an inspection level setting support mode for setting the threshold value of the inspection level.

[0020] (14) A paper feeding unit, an image forming unit that forms an image on a sheet fed and conveyed from the paper feeding unit, an image reading unit that is disposed downstream of the image forming unit on a conveyance path along which a sheet is conveyed and reads an image on the sheet, and An inspection level setting support method for image inspection executed in an image inspection system that detects an image defect using a set inspection level threshold value with a read image generated by reading of the image reading unit, feeding and conveying the printed matter from a paper feeding unit on which a printed matter printed with user content including an image defect and not a test chart is set, and In a state where the printing operation of the image forming unit is operated in a normal printing state, printing white paper data with substantially no image as the original image of a print job on the printed matter; A method for assisting in setting an inspection level, comprising: detecting an image defect based on a read image obtained by reading the printed matter with the image reading unit, and setting the threshold value of the inspection level.

Advantages of the Invention

[0021] The image inspection system according to the present invention conveys a printed matter fed from a paper feeding unit on which a printed matter with content already printed on paper is set to a conveyance path, and in a state where the printing operation of the image forming unit is turned off, detects an image defect based on a first read image obtained by reading the printed matter with an image reading unit, and has an inspection level setting support mode for setting a threshold value of the inspection level. By doing so, since the threshold value of the inspection level is set using an actually defective printed matter, the inspection level can be set appropriately.

Brief Description of the Drawings

[0022] Advantages and features provided by one or more embodiments of the present invention will be more fully understood from the following detailed description and the accompanying drawings. However, these are for illustrative purposes only and are not intended to limit the present invention. [Figure 1] It is a diagram showing a schematic configuration of an image inspection system 100 according to the present embodiment. [Figure 2] It is a block diagram showing a configuration of an image inspection system 100. [Figure 3] It is a schematic diagram for explaining a printed matter. [Figure 4] It is a flowchart showing a process of an inspection level setting support mode in the first embodiment. [Figure 5] It is a subroutine flowchart showing a process of step S14. [Figure 6A] It is an example of an operation screen used in step S120. [Figure 6B]This is an example of the operation screen used in step S120. [Figure 6C] This is an example of the operation screen used in step S120. [Figure 6D] This is an example of the operation screen used in step S130. [Figure 7] This is a subroutine flowchart showing the processing of step S19 in the first embodiment. [Figure 8A] This is an example of an operation screen for setting the test level and checking the results for that test level. [Figure 8B] This is an example of an operation screen for setting the test level and checking the results for that test level. [Figure 9] This table shows the types of image defects and example settings, along with the inspection level range. [Figure 10] This flowchart shows the image inspection process performed using preset values ​​set in the inspection level setting support mode. [Figure 11A] This is a subroutine flowchart showing the processing of step S19 in the second embodiment. [Figure 11B] This is a subroutine flowchart showing a modified version of Figure 11A. [Figure 12A] In the second embodiment, this is an example of the output of the test results presented to the user. [Figure 12B] This is an excerpt of some of the outputs from Figure 12A. [Figure 13] This is a flowchart showing the processing of the inspection level setting support mode in the third embodiment. [Figure 14] This is a subroutine flowchart showing the process in step S21. [Modes for carrying out the invention]

[0023] Embodiments of the present invention will be described below with reference to the attached drawings. However, the scope of the present invention is not limited to the disclosed embodiments. In the description of the drawings, the same elements are denoted by the same reference numerals, and redundant descriptions are omitted. Also, the dimensional ratios in the drawings are exaggerated for illustrative purposes and may differ from the actual ratios.

[0024] (Overall configuration of the image inspection system 100) The image inspection system 100 according to this embodiment will be described below with reference to Figures 1 and 2. Figure 1 is a diagram showing the schematic configuration of the image inspection system 100, and Figure 2 is a block diagram showing the configuration of the image inspection system.

[0025] The image inspection system 100 includes a DFE (Digital Front End) 10, a main unit printing unit 20, a main unit operation control unit 30, an image inspection unit 40, an operation display unit 50, a communication unit 60, a storage unit 70, and the like. These are interconnected by signal lines.

[0026] The operation display unit 50 includes a touchscreen, a numeric keypad, a start button, a stop button, etc. The operation display unit 50 displays the status of the image inspection system 100 and is used for inputting various instructions from the user through the functions of the main unit operation control unit 30. In this embodiment, the user sets the inspection level. The operation display unit 50 is also used to present the image inspection results to the user. The communication unit 60 is an interface for communicating with other devices. The image inspection system 100 communicates with the terminal device 90 via the communication unit 60. The storage unit 70 stores various data. The storage unit 70 stores various job lists, thresholds for multiple inspection levels, and preset values ​​for inspection levels (these will be described later).

[0027] The terminal device 90 is a PC (personal computer) and is operated by a user such as an administrator or operator who operates the image inspection system 100. The terminal device 90 may be used to present inspection results to the user when the inspection level setting support mode is executed in the image inspection system 100. The terminal device 90 may also be included in the image inspection system 100.

[0028] The DFE10 functions as a RIP (Raster Image Processor) 110, a color correction unit 120, a test chart generation unit 130, an ICC profile generation unit 140, and a job management unit 150. The DFE10 receives print jobs from terminal devices 90, etc., via a communication unit 60. A print job includes print data (hereinafter also referred to as the original image) and print settings. The job management unit 150 manages the start, end, progress, and execution order of these print jobs. The RIP 110 performs rasterization processing to convert the print data into page-level bitmap data based on the print settings of the print job. The ICC profile generation unit 140 generates color correction information related to ICC profiles, which are standardized by the ICC (International Color Consortium), in order to enable consistent color reproduction across different devices. The color correction unit 120 performs color correction based on the color correction information. The test chart generation unit 130 generates a test chart for calibration.

[0029] (Main body printing section 20) The main printing unit 20 includes a paper feeding unit 21, a transport unit 22, an image forming unit 23, a UV irradiation unit 24, an image reading unit 25, and a paper discharge unit 26.

[0030] The paper feeding unit 21 accommodates multiple sheets of paper 80 used for image formation and feeds them out one sheet at a time. The paper feeding unit 21 includes a paper feeding tray 211. The paper feeding tray 211 is plate-shaped and can hold one or more sheets of paper 80. The paper feeding tray 11 moves up and down according to the amount of paper 80 placed on it. The paper feeding tray 11 is held in a position where the top sheet of paper 80 is transported by the transport unit 22.

[0031] The transport unit 22 includes a first transport unit 221, a transfer unit 222, and a second transport unit 223. The image forming unit 23 includes an image forming drum 230, a paper heating unit 231, and multiple head modules (HM) 232 corresponding to the colors Y (yellow), M (magenta), C (cyan), and K (black). The image forming unit 23 is an inkjet type image forming unit, and therefore is not affected by malfunctions caused by the printing operation being turned off. In contrast, for example, in the electrophotographic method, the external additives contained in the toner function as lubricants on the photoreceptor drum, so there is a risk of malfunctions occurring when the printing operation is turned off, but this is not a problem in the inkjet method.

[0032] The first transport unit 221 includes a plurality of rollers (two in this case) and a ring-shaped belt. The belt is rotationally driven by the plurality of rollers. The first transport unit 221 includes a transport mechanism for transporting paper 80 on the belt and a supply unit that transfers the best of the paper 80 placed on the paper tray 211 to the belt. The first transport unit 221 transports the paper 80 transferred to the belt by the supply unit in conjunction with the rotational movement of the belt.

[0033] The image forming unit 23 forms an image on the paper 80 by ejecting ink onto the paper 80. The ink is, for example, UV ink. When UV light is not irradiated, UV ink undergoes a phase change between a gel state and a liquid (sol) state depending on the temperature. UV ink has a phase change temperature of, for example, about 100°C, and uniformly liquefies (becomes a sol) when heated above this phase change temperature. On the other hand, this ink gels at temperatures below the phase change temperature, including normal room temperature (0°C to 30°C).

[0034] The image forming drum 230 carries the paper 80 along its cylindrical outer surface and transports the paper 80 as it rotates. The transport surface of the image forming drum 230 faces the paper heating unit 231, multiple head modules 232, UV irradiation unit 24, and image reading unit 25. The paper 80 carried and transported by the image forming drum 230 undergoes image formation processing.

[0035] The transfer unit 222 is provided between the first transport unit 221 and the image forming drum 230. The transfer unit 222 transfers the paper 80 transported by the first transport unit 221 to the image forming drum 230. The transfer unit includes a swing arm and a cylindrical transfer drum, etc. The swing arm supports one end of the paper 80 transported by the first transport unit 221. The transfer drum transfers the paper 80 supported by the swing arm to the image forming drum 230. The transfer unit 222 picks up the paper 80 on the transport unit 221 with the swing arm and transfers it to the transfer drum, thereby guiding the paper 80 in a direction along the outer circumferential surface of the image forming drum 230 and transferring it to the image forming drum 230.

[0036] The paper heating unit 231 heats the paper 80 supported on the image forming drum 230. The paper heating unit 231 includes, for example, an infrared heater and generates heat in response to the application of electricity. The paper heating unit 231 is located near the outer surface of the image forming drum 230 and upstream of the head module 232, along the direction in which the paper 80 is transported by the rotation of the image forming drum 230. The heating of the paper heating unit 231 is controlled by the main printing unit 20 (control unit) so that the paper 80 supported on the image forming drum 230 and passing near the paper heating unit 231 reaches a predetermined temperature.

[0037] Multiple head modules 232 form an image on the paper 80 supported on the image forming drum 230 by ejecting C, M, Y, and K inks. A head module 232 is provided individually for each CMYK color. In Figure 1, the head modules 232 corresponding to each YMCK color are provided in this order along the transport direction of the paper 80, which is transported as the image forming drum 230 rotates.

[0038] In this embodiment, multiple head modules 232 are mounted on the carriage for each color. On each carriage, multiple head modules are arranged alternately in a staggered pattern. The multiple head modules 232 mounted on the carriage as a whole are provided with a length (width) that covers the entire length (width) of the paper 80 with the maximum printable width in the direction perpendicular to the transport direction of the paper 80. In other words, the image forming unit 23 is a one-pass line head type inkjet recording device. The head module 232 can be configured as a line head by arranging multiple inkjet heads (not shown). Furthermore, a retraction mechanism is connected to the carriage on which the head modules 232 are mounted, and the retraction mechanism moves the carriage and the head modules 232 contained therein in the rotation axis direction of the image forming drum 230. The retraction mechanism moves the carriage axially inward by a distance equivalent to the maximum paper width (several hundred mm (e.g., 600 mm)). In other words, the head module 232, which is positioned on the carriage, is moved to a retracted position where it does not face the image forming drum 230 (or the paper 80 on which it is supported). This prevents dirt (ink) from the head module 232 from adhering to the paper 80, and also prevents damage to both the paper 80 and the head module 232 from contact.

[0039] The UV irradiation unit 24 irradiates energy rays to cure the ink after it has been ejected onto the paper 80. The UV irradiation unit 24 includes a fluorescent tube, such as a low-pressure mercury lamp, and irradiates energy rays such as ultraviolet light by emitting light from the fluorescent tube. The UV irradiation unit 24 is located near the outer surface of the image forming drum 230 and is positioned downstream of the head module 232 in the direction of transport of the paper 80 due to the rotation of the image forming drum 230. The UV irradiation unit 24 irradiates energy rays onto the paper 80, which is supported on the image forming drum 230 and has ink ejected from it, and cures the ink ejected onto the paper 80 by the action of these energy rays.

[0040] The image reading unit 25 optically reads an image on the recording medium and generates image data (also called read data). The image reading unit 25 is located downstream of the image forming unit 23 on the transport path. The image data generated by the image reading unit 25 is sent to the image inspection unit 40. The image reading unit 25 is a sheet-feed scanner that reads while transporting the original paper. The image reading unit 25 includes a sensor array, a lens optical system, an LED (Light Emitting Diode) light source, and a housing that houses these components. The sensor array is a color or monochrome line sensor in which multiple optical elements (e.g., CCD (Charge Coupled Device)) are arranged in a line along the main scanning direction, and the reading area in the main scanning direction corresponds to the entire width of the recording medium. The optical system consists of multiple mirrors and lenses. Light from the LED light source illuminates the surface of the recording medium at the reading position. The image at this reading position is guided by the optical system and formed on the sensor array. It is preferable that the reading resolution of the image reading unit 25 be higher than the printing resolution of the image forming unit 23. For example, if the printing resolution of the image forming unit 23 is 1200 dpi (dots per inch), it is preferable that the reading resolution of the image reading unit 25 be higher, such as 2400 dpi or 4800 dpi.

[0041] The second transport unit 223 transports the paper 80, which has been irradiated with energy rays by the UV irradiation unit 24, from the image forming drum 230 to the paper discharge unit 26. The second transport unit 223 includes a plurality of rollers (two in this case), a ring-shaped belt, etc. The belt is rotationally driven by the plurality of rollers. The second transport unit 223 includes a transport mechanism for transporting the paper 80 on the belt, and a cylindrical transfer drum for transferring the paper 80 from the image forming drum 230 to the transport mechanism. The second transport unit 223 transports the paper 80 transferred to the belt by the transfer drum and sends it to the paper discharge unit 26 via the belt.

[0042] The paper output unit 26 stores the paper 80 that has been fed out from the image forming unit 23 by the second transport unit 223. The paper output unit 26 includes a plate-shaped paper output tray 261, etc., and places the image-formed paper 80 on the paper output tray 31. In addition to the paper output tray 261, the paper output unit 26 may also include a purge tray. Paper 80 that has been determined to be defective by image inspection is discharged into the purge tray.

[0043] (Main unit operation control unit 30) The main unit operation control unit 30 functions as a paper setting 310, print setting 320, print command 330, image quality adjustment 340, and carriage operation 350 through processing via the operation display unit 50 or the terminal device 90. Paper setting 310 sets the paper stored in the paper tray 211 based on user input via the operation display unit 50 or the like. Paper settings include, for example, paper type, basis weight, and paper size.

[0044] The print settings 320 configures print settings based on user input via the operation display unit 50, etc. The print command 330 accepts a print execution command based on user input via the operation display unit 50, etc. The image quality adjustment 340 starts image quality adjustment based on user input via the operation display unit 50, etc. The carriage operation 350 activates the retraction mechanism in response to user input, causing the carriage on which the head module 232 is located to move to the retracted position or the image forming position.

[0045] (Image Inspection Department 40) The image inspection unit 40 includes a CPU, RAM, ROM, etc. The image inspection unit 40 functions as a RIP image acquisition unit 410, a read image acquisition unit 420, an inspection level setting unit 430, a comparison inspection unit 440, an inspection result presentation unit 450, a report generation unit 460, and an inspection preset value setting unit 470. The image inspection unit 40 corresponds to an image inspection device.

[0046] The RIP image acquisition unit 410 acquires the RIP image generated by the DFE 10. The read image acquisition unit 420 acquires the read image generated by the image reading unit 25. The inspection level setting unit 430 sets the inspection level based on user input via the operation display unit 50, etc. The set inspection level is used as a preset value for subsequent image inspections.

[0047] The comparison inspection unit 440 performs the following processes a1 to a3.

[0048] (Process a1) Generation of reference image: Here, the reference image can be of either type 1 or type 2 as follows.

[0049] "Type 1" is a RIP image generated by applying various processing steps as needed to the original image. Here, these various processing steps are those that establish a one-to-one correspondence between the pixels of the scanned image and the pixels of the reference image, such as processing related to position, resolution, color, etc.

[0050] "Type 2" is a scanned image obtained by the image reading unit 25 after the printed material provided by the user and placed in the paper feed tray 211 has been transported and read. This printed material is a selected print from among those obtained by printing the same original image (print data), and is evaluated by the user visually, etc., as a print without image defects or a print in which no image defects can be detected (hereinafter also referred to as the correct paper sample). Hereinafter, the scanned image obtained by reading this correct paper sample with the image reading unit 25 will also be referred to as the "second scanned image" (the first scanned image will be described later).

[0051] (Relationship between various samples, reference samples, and test samples) Here, we will explain various samples, reference samples, and inspection samples. Figure 3 is a schematic diagram illustrating printed materials. Figure 3(a) shows Type 1. In Type 1, the original image is used as the reference image, and the RIP image obtained by RIP processing with RIP110 is used as the reference image. Figure 3(b) shows Type 2. In Type 2, the above-mentioned correct paper sample is used as the reference image, and the read image (second read image) obtained by feeding and transporting this paper and reading it with the image reading unit 25 is used as the reference image.

[0052] Figure 3(c) shows an inspection sample. The inspection sample is a printout selected by the user from among multiple printouts obtained by printing the same source image (print data) as in Figure 3(a) or Figure 3(b), and is a read image obtained by reading a printout containing image defects. This printout containing image defects is not a test chart with defects intentionally added, but a printout with user content printed on it, which naturally came to contain image defects (hereinafter also referred to as a defective paper sample). The determination of these image defects was evaluated by the user by visual inspection, etc. In the example in Figure 3(c), there are two streaks and two stains as image defects. Figure 3(d) is a test chart with artificial streaks added to a uniform halftone background as a comparative example, and Figure 3(e) is a printout with user content printed on it, which naturally came to contain image defects. In Figure 3(e), it is a printout with the source image of user content printed on it, and natural streaks have occurred during printing. In the inspection level setting support mode, instead of using a test chart of artificial defects like the one in Figure 3(d), a sample containing natural defects like the one in Figure 3(e) is used as the inspection sample shown in Figure 3(c).

[0053] In Figure 3(c), the user-selected inspection sample (defective paper sample) is fed and transported, and the image obtained from reading it by the image reading unit 25 is used as the inspection image. This image obtained from reading the defective paper sample is called the "first reading image".

[0054] (Process a2) Generation of difference image: The comparison inspection unit 440 generates a difference image by comparing a reference image with a read image (hereinafter also referred to as the inspection image) obtained by reading the image formed on the paper to be inspected. Specifically, it calculates the difference (error) in pixel values ​​for each corresponding pixel in both images and obtains a difference image (image data on a page-by-page basis). There are two types of comparisons: in comparison 1 using a type 1 reference sample, the reference image of the RIP image is compared with the inspection image, and in comparison 2 using a type 2 reference sample, the second read image is compared with the inspection image.

[0055] In the normal image inspection mode, the paper subject to inspection is the paper on which the RIP image of the original document has been printed. In the normal image inspection mode, the scanned image obtained by reading this normal printed material is the subject of inspection. On the other hand, in the inspection level setting support mode, the paper subject to inspection is the aforementioned "defective paper sample". In the inspection level setting support mode, with the printing operation of the image forming unit 23 of the main unit print unit 20 turned OFF, the scanned image obtained by reading this defective paper sample with the image reading unit 25 is the subject of inspection.

[0056] (Process a3) Image defect detection using inspection level (preset value): The comparison inspection unit 440 analyzes the difference image and, through clustering, groups pixels whose pixel value (difference pixel value) is equal to or greater than a predetermined value into connected or consecutive blocks. For each of these blocks (hereinafter also referred to as defect candidates), a pass / fail judgment is made by comparing it with an inspection level threshold, and if it is above the threshold, it is determined to be an image defect. The types of image defects subject to inspection include smudges, streaks, etc. In addition, there are multiple inspection settings (also referred to as setting items) for each type of image defect. For example, for smudges, there are settings for size, density, edge sensitivity, and tolerance for smudges in the reference image (see Figure 9 below).

[0057] The inspection result display unit 450 presents the inspection results to the user through the operation display unit 50, etc. (see Figure 8A, described later). Based on these presented inspection results, the user makes a judgment on the appropriateness of the inspection level.

[0058] The report generation unit 460 generates a report that visualizes the inspection results of the comparative inspection unit 440. The report includes the read image of the inspection target (image of the defective paper sample), the presence or absence of image defects at each inspection level, and information indicating the type, location (XY coordinates on the page), and number of occurrences of the image defects. In addition, areas (blocks) determined to be image defects are annotated by surrounding the image defect or indicating the vicinity with arrows or symbols. The report is output in PDF file format, or converted from PDF to a file format such as JPEG and displayed on the operation display unit 50. An example of the report will be described later (Figure 12A, etc.).

[0059] The inspection preset value setting unit 470 executes the inspection level setting support mode. In the inspection level setting support mode, the inspection preset value setting unit 470 sets the preset value by one of the following methods b1 or b2.

[0060] (b1) The inspection results at the current inspection level setting (preset value) are presented to the user, and the user's judgment on the validity of this inspection level is obtained. For example, the results are displayed on the operation display unit 50 or the display unit of the terminal device 90. In addition, the user requests a change in the inspection level (increase / decrease / speed) through the presenting device, and the user is then presented with the inspection results at the changed inspection level, and the user's judgment on the validity of the changed inspection level is obtained. If the user responds that it is valid, the inspection preset value setting unit 470 sets that inspection level as a preset value and stores it in the storage unit 70.

[0061] (b2) The user is presented with the inspection results for each of the multiple inspection levels, along with the setting value for that inspection level. The presentation method may be, for example, output as a PDF or printed. The user selects an inspection result for an appropriate inspection level from among the multiple inspection results presented. The user sends the selection result to the image inspection system 100 through the operation display unit 50 or the input unit of the terminal device 90. The inspection preset value setting unit 470 receives this and sets the inspection level (or combination of inspection levels) as a preset value and stores it in the storage unit 70.

[0062] (Inspection level setting support mode) Next, with reference to Figures 4 to 9, the inspection level setting support mode performed in the image inspection system 100 according to the first embodiment will be described.

[0063] Figure 4 is a flowchart showing the processing in the inspection level setting support mode.

[0064] (Step S11) The user issues an instruction to start the inspection level setting support mode through the operation screen of the operation display unit 50 or the operation screen of a web application running on the terminal device 90 (hereinafter, these are collectively referred to simply as the operation screen).

[0065] (Step S12) The image inspection system 100 starts the inspection level setting support mode in response to instructions.

[0066] (Step S13) The user selects either type 1 or type 2 of the reference image through the operation screen. Figure 6A shows an example of the operation screen used in step S13, etc. The user can select RIP or scan using the radio buttons in area a11. These correspond to types 1 and 2, respectively, as explained in Figure 3, etc.

[0067] (Step S14) The comparison inspection unit 440 generates and saves a reference image. Figure 5 is a subroutine flowchart showing the process in step S14.

[0068] (Step S110) As shown in Figure 5, the comparison inspection unit 440 determines the type of reference image based on the user's instructions in step S13. If it is type 1 (RIP image), the comparison inspection unit 440 proceeds to step S120; if it is type 2 (scan method), it proceeds to step S140.

[0069] (Step S120) The comparison inspection unit 440 receives instructions to identify the original image. In the example in Figure 6A, the user has selected "RIP" in area a11, so area a13 is grayed out and selection is disabled. Next, the user presses the button in area a12. This transitions to the operation screen shown in Figure 6B. On the operation screen in Figure 6B, the user selects the desired print job (a job containing the reference original image). As shown in Figure 6B, after selecting a row of print jobs, pressing the selection button a15 transitions to the operation screen shown in Figure 6C. On the operation screen in Figure 6C, the original images for each of the multiple pages included in the selected print job are displayed in a list. After the user selects the desired page, pressing the selection button a16 completes the selection of the original image (image data).

[0070] (Step S130) The comparison inspection unit 440 starts generating a RIP image in response to the press of the selection button a16. Here, the comparison inspection unit 440 generates a RIP image by performing various appropriate processing on the original image selected by the user in step S120. This RIP image is used as a reference image.

[0071] (Step S140) Figure 6D shows an example of the operation screen used in step S140. When the user selects scan using the radio button in area a11, area a12 is grayed out and the selection is disabled. After the user places a correct paper sample (labeled "reference sample" in Figure 6D) in the paper tray 211, the user presses the button in area a13. As described above, the correct paper sample is a printed document that the user has evaluated visually or otherwise and which has no image defects, or in which no image defects can be detected. Pressing the button in area a13 acts as a trigger to start the correct paper sample being fed from the paper tray 211. At this time, the main unit print unit 20 turns off the printing operation of the image forming unit 23. Specifically, the main unit print unit 20 does not operate the paper heating unit 231 or the head module 232. The UV irradiation unit 24 is also not operated. At this time, the carriage including the head module 232 may also be moved to the retracted position by the retraction mechanism.

[0072] (Step S150) The image reading unit 25 reads the printed material, i.e., the correct answer sheet sample, that has been transported to the reading position and generates a read image. This read image is used as a reference image.

[0073] (Step S160) The comparison inspection unit 440 saves the reference image generated in step S130 or step S150 to the storage unit 70 or page memory (cache memory, etc.). This completes the processing of the subroutine flowchart in Figure 5 (return), and the process returns to the main flowchart in Figure 4 from step S14 onwards.

[0074] (Step S15) The user places a defective paper sample in the paper tray 211. After placing the sample, the user presses the scan start button a14 on the operation screen shown in Figure 6A or Figure 6D (in Figure 6A, the defective paper sample is labeled as "inspection sample"). Here, the defective paper sample is, as described above, a printed document containing image defects, not a test chart with defects intentionally added, but a printed document with user content printed on it that naturally contains image defects. The source image from which the defective paper sample was printed is (a) the same as the source image of the reference image selected in step S120 in the case of type 1, or (b) the same as the source image of the correct paper sample set in step S140 in the case of type 2.

[0075] (Step S16) Pressing the button in area a14 acts as a trigger, causing a defective paper sample to be fed from the paper tray 211. At this time, the main unit print unit 20 turns off the printing operation of the image forming unit 23, similar to step S140.

[0076] (Step S17) The image reading unit 25 reads the printed material, i.e., the defective paper sample, that has been transported to the reading position and generates a read image. This read image is used as an inspection image.

[0077] (Step S18) The inspection level setting unit 430 retrieves an inspection preset from the storage unit 70 and sets it as the inspection level. The inspection preset value here is either a previously set value or the default value.

[0078] (Step S19) Here, the image inspection system 100 interacts with the user, and the inspection result presentation and inspection level determination processes described below are executed.

[0079] Figure 7 is a subroutine flowchart showing the processing of step S19 in the first embodiment.

[0080] (Step S210) The comparison inspection unit 440 performs the inspection by comparing the reference image and the inspection image at the previously set inspection level. The reference image is generated in step S14, and the inspection image is generated in step S17 based on the defective paper sample. Note that in the first inspection in step S210 (when step S2550 is not performed), the inspection level used is the inspection level acquired in step S18.

[0081] (Step S220, S230) The inspection result presentation unit 450 presents the inspection results to the user. Figure 8A is an example of an operation screen displayed on the operation display unit 50 or terminal device 90. On the operation screen, area a1 shows inspection levels for multiple setting items for the types of image defects, such as dirt and streaks. Area a22 shows the inspection results for that inspection level. Figure 9 shows examples of these image defect types and setting items. For example, for dirt image defects, there are setting items 1 to 4 related to "size of dirt," "intensity of dirt," "edge sensitivity," and "tolerance for dirt in the reference image." For streak image defects, there are setting items 1 to 5 related to "streak intensity," "highlight exclusion," "edge sensitivity," "back-image sensitivity," and "streak length determination." Each setting item has multiple preset levels, for example, 10 levels. The thresholds for each of the multiple inspection levels for each item are stored in the storage unit 70 beforehand.

[0082] Here, the user can select one of three default levels: lenient, normal, or strict. For each setting item, the higher the level value, the stricter the judgment becomes, and defects are more easily detected. If the level is too low, false positives (false detections) are likely to occur, where image defects that should be detected are not found. Conversely, if the level is too high, false positives (false detections) are likely to occur, where normal images are mistakenly identified as defective. One of the default setting levels selected by the user is stored as a preset value in the memory unit 70. In the example shown in Figure 8A, the default value of "normal" is set as the preset value for the inspection level of each item.

[0083] Area a22 displays the scanned image of the defective paper sample, which is the inspection image to be inspected. This scanned image contains defect candidates c1, c2, c3, and c4, which are clusters of difference pixels. Of these defect candidates c1 to c4, the comparative inspection unit 440 at the inspection level shown in area a21 determines that defect candidates c1 and c2 are image defects. Defect candidates c3 and c4 are not determined to be image defects. The image defects c1 and c2, which were determined to be image defects, are marked with annotation marks m1 and m2. Mark m1 is an arrow corresponding to the type of streak of the image defect, and mark m2 is a ring surrounding it corresponding to the type of stain. The user can easily check the inspection results at the current inspection level by looking at the displayed image of the defective paper sample shown in area a22 on the operation screen.

[0084] (Step S240) If the user is dissatisfied with the test results, they will not complete the adjustment (NO), but will proceed to step S250. On the other hand, if they are satisfied with the test results, they will decide to complete the adjustment (YES) and proceed to step S260.

[0085] (Step S250) The user readjusts the inspection level and notifies the system of the adjusted inspection level settings. Specifically, on the operation screen shown in Figure 8A, the user can change the inspection level by pulling down the downward-pointing triangle located next to each setting. After changing the level of up to one or more setting items, the user presses the execute button a23, and the adjusted settings are notified to the image inspection system 100.

[0086] (Steps S210~S230) In response, the image inspection system 100 re-executes steps S210-S230, performs a re-inspection with the adjusted inspection level settings, and presents the inspection results to the user. The user then refers to the inspection results.

[0087] Figure 8B shows an example of the operation screen displayed according to the adjusted inspection level. In Figure 8B, the setting of the area enclosed by the dashed line in area a21 has been changed to a stricter setting, and the inspection results after this change are shown in area a22.

[0088] Area a22 in Figure 8B shows the scanned image of the defective paper sample, which is the inspection image to be inspected. Of the defect candidates c1 to c4, the comparative inspection unit 440, at the inspection level shown in area a21, determines that defect candidates c3 and c4 are also image defects in addition to defect candidates c1 and c2. Accordingly, annotation marks m3 and m4 are also assigned to image defects c3 and c4.

[0089] (Step S260) If the user determines that the adjustment is complete (that they are satisfied with the current inspection level settings for the inspection results), they can press the preset button a24, which will notify the image inspection system 100 of this.

[0090] (Step S270) The inspection preset value setting unit 470 sets the current inspection level to a preset value in response to the notification. This completes the processing of the subroutine flowchart in Figure 7 (return), and the process returns to step S19 onwards in the main flowchart in Figure 4.

[0091] (Step S20) The inspection preset value setting unit 470 registers the inspection level as a preset value in the storage unit 70 and then terminates (end).

[0092] In this embodiment, the printed material fed from the paper feed unit, which already has content printed on it, is transported to the transport path. With the printing operation of the image forming unit turned OFF, the printed material is read by the image reading unit, and an inspection level setting support mode is provided to detect image defects based on the first read image obtained, thereby setting the threshold for the inspection level. In addition, multiple inspection levels with different thresholds are pre-set in the inspection level setting support mode. Multiple inspection results for each of the multiple inspection levels are presented to the user, and the threshold for the inspection level used in the inspection result selected by the user from the presented inspection results is registered as a preset value to be used for inspection. This allows the inspection level to be set appropriately by setting the threshold for the inspection level using a printed material in which defects actually occurred.

[0093] (Normal image inspection mode) Next, with reference to Figure 10, the normal image inspection mode performed by the image inspection system 100 will be described. In the normal image inspection mode, images are inspected using preset values ​​registered through the inspection level setting support mode processing shown in Figure 4 and other figures described above.

[0094] (Step S31) When the image inspection system 100 receives a print job from a user via the operation display unit 50 or terminal device 90, it starts the print job (YES). The data of the received print job includes print data (original image) and print settings.

[0095] (Step S32) The RIP110 generates a RIP image from the original image based on the print settings of the print job. The RIP image acquisition unit 410 of the image inspection unit 40 acquires this image and uses it as a reference image.

[0096] (Step S33) The main unit's printing unit 20 prints on the paper fed from the paper tray 211 based on the RIP image.

[0097] (Step S34) The image reading unit 25 reads the image formed on the paper as the object to be inspected and generates a read image. The read image acquisition unit 420 of the image inspection unit 40 acquires this read image and uses it as an inspection image.

[0098] (Step S35) The comparison inspection unit 440 and the storage unit 70 acquire a preset value for the inspection level. The image is then inspected by performing image defect detection using this inspection level (preset value) (as described in (a3) ​​above). If one or more image defects are found during the image inspection, the paper (printed material) is determined to be defective, and the paper is ejected into the purge tray. This process is continued until the print job is completed (end).

[0099] The above describes the processing in normal image inspection mode. In normal image inspection mode, the image inspection unit 40 continuously transports the paper 80 and forms an image on the paper, while performing image inspection using the read image obtained by the downstream image reading unit 25 on the transport path. In this case, the maximum allowable processing time in normal image inspection mode is the cycle of the continuously transported paper 80. For example, with a printing speed of 3000 sheets / hour, the maximum allowable processing time is 1.2 seconds per sheet. The inspection level setting support mode described above does not have such constraints, so the processing time in inspection level setting support mode is longer than the "maximum allowable processing time" of normal image inspection mode.

[0100] (Second embodiment) Next, with reference to Figures 11A, 11B, and 12, the inspection level setting support mode in the second embodiment will be described. In the first embodiment described above, the inspection results were presented to the user by displaying them on the display unit (Figure 8A, etc.). In the second embodiment, the inspection results are presented to the user by outputting an inspection result report, as will be described below.

[0101] Figure 11A is a subroutine flowchart showing the process of step S19 in Figure 4 in the second embodiment.

[0102] (Step S410) The inspection preset value setting unit 470 of the image inspection unit 40 adds all combinations of inspection levels to the queue. For example, if the type of image defect is dirt, and there are four inspection level setting items, each of which can be set in 10 steps, then there are n=1000 (=10^4) possible combinations. The inspection preset value setting unit 470 adds, for example, 1000 combinations to the queue. In this case, the inspection preset value setting unit 470 may use fixed values ​​for some settings to prevent them from changing. For example, in the example shown in Figure 9, the dirt setting 3 (edge ​​sensitivity) and setting 4 (standard tolerance), which do not change the default Lv between loose / normal / strict, may be set to fixed values. In this case, n=100 (=10 2 ) This will be the case.

[0103] Figure 11B is a modified version of Figure 11A. Step S410 in Figure 11A may be modified to step S415 shown in Figure 11B. In step S415, the default is used as the baseline, and combinations of levels one level above and below the default are added to the queue. The default is shown in Figure 9. For example, if "normal" is selected as the default, each setting item is changed in three stages instead of 10: default value, default value + 1, and default value - 1. In this case, since there are four setting items and three stages each, the total number of combinations is n=81 (=3^4), which helps to prevent the number of test results from becoming enormous.

[0104] (Step S420) The comparison inspection unit 440 selects a combination of inspection levels from the queue and performs the inspection under these conditions. The inspection here is the same as in step S210 described above, except that the inspection levels used are different.

[0105] (Step S430) The inspection preset value setting unit 470 repeats the process in step S420 if all combinations have not been completed (NO), and proceeds to step S440 if all combinations have been completed (YES).

[0106] (Step S440) The report generation unit 460 creates an inspection results report describing each combination of inspection levels and the corresponding inspection results. The image inspection unit 40 also sends the generated report to the user. The report can be output as a PDF file or printed on paper. Figure 12A shows an example of the inspection results output presented to the user in the second embodiment. In Figure 12A, the report is output as one PDF page file for each combination of inspection levels, totaling n pages.

[0107] Figure 12B shows the content of four pages from the n pages of Figure 12A with different combinations of inspection levels. In Figure 12B (1), the inspection level is too lenient (small numerical value), resulting in false positives. In Figure 12B (1), no image defects were detected. In Figure 12B (2), the inspection level is slightly too lenient, resulting in false positives. In Figure 12B (2), some image defects were detected, but some were not. In Figure 12B (3), detection was successful. In Figure 12B (4), the inspection level is too strict, resulting in false positives. In Figure 12B (4), areas that are not image defects were identified as image defects.

[0108] (Step S450, S460) The user reviews the output report and selects the combination of test levels that yielded the desired test result. For example, from the combinations that yielded the desired test result (test level C), the user selects the combination of test levels with the least stringent conditions. The user then enters the selected combination through the operation screen. For example, in the example in Figure 12B, the user enters the number (e.g., test level C) listed on the page that yielded the desired test result.

[0109] (Step S470) The inspection preset value setting unit 470 determines preset values ​​based on the input. For example, if inspection level C is input, the unit determines the inspection level (each inspection item) corresponding to inspection level C shown in Figure 12B as a preset value.

[0110] Thus, in the second embodiment, the results are presented to the user by outputting a report of the test results. Even in this manner, the same effects as in the first embodiment can be obtained.

[0111] (Third embodiment) Next, with reference to Figures 13 and 14, the inspection level setting support mode in the third embodiment will be described. In the embodiments described above, such as the first embodiment, the printing operation was turned OFF in the inspection level setting support mode. In the third embodiment, the printing operation is not turned OFF, and a blank page is printed. A blank page here means a page that is essentially free of images, that is, a document image in which no images are drawn at all, or where very few images are drawn.

[0112] Figure 13 is a flowchart showing the processing of the inspection level setting support mode in the third embodiment. Figure 14 is a subroutine flowchart showing the processing of step S21 in Figure 13. In Figure 13, steps other than S21 and S22 correspond directly to Figure 4. Similarly, in Figure 14, steps other than S145 correspond directly to Figure 5. For corresponding processes, the same step number is used to omit further explanation.

[0113] (Steps S11-S13) The processes up to this point are the same as steps S11 to S13 in Figure 4.

[0114] (Step S21) In step S21, the comparison inspection unit 440 generates and saves a reference image. Figure 14 is a subroutine flowchart showing the process in step S21.

[0115] (Steps S110, S145) The comparative inspection unit 440 proceeds to step S145 if it is type 2 (scanning method). The processing for type 1 (RIP image) is the same as in the first embodiment of Figure 4, and therefore the explanation is omitted.

[0116] In step S145, the user places the correct answer sheet sample in the paper tray 211 and presses the button in area a13 of Figure 6D. Pressing the button in area a13 acts as a trigger, and the correct answer sheet sample is fed from the paper tray 211. At this time, unlike the first embodiment, the main unit print unit 20 turns on the printing operation of the image forming unit 23. Specifically, the main unit print unit 20 operates the paper heating unit 231, the head module 232, the UV irradiation unit 24, etc. At this time, the image inspection unit 40 prints a blank sheet as the original image. That is, no additional images are printed on the correct answer sheet sample.

[0117] (Steps S120, S130, S150, S160) The process is the same as in Figure 5, so the explanation is omitted. The comparison inspection unit 440 saves the reference image generated in step S150 to the storage unit 70 or page memory (cache memory, etc.). This completes the processing of the subroutine flowchart in Figure 14 (return), and the process returns to the main flowchart in Figure 13 from step S21 onwards.

[0118] (Step S22) As shown in Figure 13, in step S15, the defective paper sample that the user has placed in the paper tray 211 is fed and transported. At this time, the main unit print unit 20 turns on the printing operation of the image forming unit 23, just as in step S145. At this time, just as in step S145, the image inspection unit 40 prints a blank sheet of paper as the original image. In other words, no additional images are printed on the defective paper sample.

[0119] (Steps S17-S20) In step S17, the image reading unit 25 reads the printed material, i.e., the defective paper sample, that has been transported to the reading position and generates a read image. This read image is used as an inspection image. The processing in steps S17 to S20 is as described in Figure 4. The image inspection unit 40 presents the user with inspection results for several different inspection levels, and the user selects the desired inspection result from among them. The inspection preset value setting unit 470 then registers the threshold value of the inspection level used in the selected inspection result as a preset value to be used for inspection.

[0120] In this third embodiment, the same effects as those of the first and second embodiments can be obtained.

[0121] The configuration of the image inspection system 100 described above, and the vibration evaluation method performed by these devices, are described in part in order to explain the features of the above embodiments, and are not limited to the above configuration, and can be modified in various ways within the scope of the claims.

[0122] For example, if the image inspection unit 40 functions as an image inspection device, it may be placed on the terminal device 90.

[0123] Furthermore, the means and methods for performing various processing in the image inspection system 100 according to the above embodiment can be implemented by either a dedicated hardware circuit or a programmed computer. The program may be provided, for example, on a computer-readable recording medium such as a USB memory stick or a DVD (Digital Versatile Disc)-ROM, or it may be provided online via a network such as the Internet. In this case, the program recorded on the computer-readable recording medium is usually transferred to and stored in a storage unit such as a hard disk. The program may also be provided as a standalone application software, or it may be incorporated into the software of the device as a function of the device.

[0124] While embodiments of the present invention have been described and illustrated in detail, the disclosed embodiments are for illustrative purposes only and are not limiting. The scope of the present invention should be interpreted in accordance with the language of the appended claims. [Explanation of Symbols]

[0125] 100 Image Inspection Systems 10 DFE 20 Main unit printing section 21 Paper feed section 22 Conveying section 23 Image forming unit 24 UV irradiation section 25 Image reading unit 26 Paper output section 30 Main Unit Operation Control Unit 40 Imaging Inspection Department 50 Operation display section 60 Communications Department 70 Storage section 90 Terminal devices

Claims

1. The paper feeding section, An image forming unit that forms an image on paper fed from the aforementioned paper feeding unit and transported paper, The system includes an image reading unit, which is located downstream of the image forming unit on the transport path through which the paper is transported, and reads the image on the paper. An image inspection system that uses a read image generated by the reading of the image reading unit to detect image defects using a set inspection level threshold, An image inspection system having an inspection level setting support mode that transports printed materials fed from a paper feed unit, which already has content printed on the paper, to the transport path, and, with the printing operation of the image forming unit turned OFF, detects image defects based on a first read image obtained by reading the printed materials with the image reading unit, thereby setting a threshold for the inspection level.

2. The image inspection system according to claim 1, wherein the content is user content containing image defects, not a test chart.

3. The RIP image of the aforementioned user content is used as the reference image. The image inspection system according to claim 2, wherein the first read image is used as an inspection image, and image defects are detected by comparative inspection between the inspection image and the reference image.

4. Among the printed materials obtained by printing the RIP image of the user content in the image forming unit, A printed document without image defects is used as a correct paper sample. The correct paper sample is fed and transported from the paper feed unit where the correct paper sample is set. With the printing operation of the image forming unit turned OFF, the correct paper sample is read by the image reading unit, and the second read image obtained is used as the reference image. The image inspection system according to claim 2, wherein the first read image is used as an inspection image, and image defects are detected by comparative inspection between the inspection image and the reference image.

5. Multiple test levels, each with a different threshold, are pre-set, and multiple test results based on each of these test levels are presented to the user. The image inspection system according to claim 3 or claim 4, wherein the inspection level used in the inspection result selected by the user from among the presented inspection results is registered as a preset value to be used for inspection.

6. The image inspection system according to claim 5, wherein for a single type of image defect, there are multiple setting items, and for each setting item, multiple inspection levels are pre-set, and the inspection is performed using a combination of the inspection levels of the multiple setting items, and the inspection results of the combination of the inspection levels of the multiple setting items are presented to the user.

7. The image inspection system according to claim 6, wherein the presentation to the user is a display on the display unit.

8. The image inspection system according to claim 6, wherein the information presented to the user is output as a report of the inspection results.

9. A reference image generated based on the RIP image of the print data of the print job, The image inspection system according to claim 5, wherein a normal image inspection mode is performed, in which the RIP image is printed by the image forming unit, the printed material is read by the image reading unit, the read image is used as the inspection image, and image defects are detected by comparison inspection with the inspection image.

10. The image inspection system according to claim 9, wherein the processing time of the inspection level setting support mode is longer than the maximum processing time allowed in the normal image inspection mode.

11. The image inspection system according to claim 1, wherein the image forming unit is an inkjet type image forming unit that ejects ink from the nozzles of a head module onto a sheet of paper to form an image.

12. The image inspection system according to claim 11, wherein when the inspection level setting support mode is executed, the image forming unit moves the carriage on which the head module is installed to a retracted position where it is not facing the paper.

13. An image inspection device that detects image defects using a set inspection level threshold, which is located downstream of the image forming unit on a transport path through which paper is transported, and uses a read image generated by reading an image on the paper from the image reading unit, An image inspection device having an inspection level setting support mode which feeds and transports a printed document containing user content with image defects (not a test chart) from a paper feed unit, and detects image defects based on a first read image obtained by reading the printed document with the image reading unit while the printing operation of the image forming unit is turned OFF, thereby setting a threshold for the inspection level.

14. The paper feeding section, An image forming unit that forms an image on paper fed from the aforementioned paper feeding unit and transported paper, The system includes an image reading unit, which is located downstream of the image forming unit on the transport path through which the paper is transported, and reads the image on the paper. A method for supporting the setting of inspection levels for an image inspection performed in an image inspection system that detects image defects using a set inspection level threshold, using a read image generated by the reading of the image reading unit, The steps include feeding and transporting a printed document from a paper feed unit into which a printed document containing user content with image defects (not a test chart) is set, With the printing operation of the image forming unit in the normal printing state, the step of printing a blank document with virtually no image on the printout as the source image for the print job, A method for supporting the setting of inspection levels, comprising the step of setting a threshold for the inspection level by detecting image defects based on a read image obtained by reading the printed material with the image reading unit.

Images