Diagnostic device, control method thereof, program, and image forming device

Abstract

To provide a mechanism for suitably diagnosing a sign of abnormality of an image formation device, while suppressing a processing load, for example.SOLUTION: When an image is formed on a recording medium by an image formation part (printing part), a diagnosis device determines whether or not to execute sign diagnosis processing to detect a sign of abnormality of an image formation device. The diagnosis device executes sign diagnosis processing on a read-out image obtained by reading an image formed by the image formation part by a read-out part, when determining that it executes the sign diagnosis processing, and makes the image formation part perform automatic repair before the sign of the abnormality reaches a predetermined level of abnormality, when detecting the sign of the abnormality.SELECTED DRAWING: Figure 4

Description

[Technical Field]

[0001] The present invention relates to a diagnostic device that diagnoses an apparatus from a scanned image of a formed image, a control method therefor, a program, and an image forming apparatus. [Background technology]

[0002] Some abnormalities in printed images deteriorate in image quality as the number of printed sheets increases. Based on this characteristic, it is possible to detect "image abnormalities at an image quality level acceptable to the user" (hereinafter referred to as "signs") and predict the occurrence of "image abnormalities at an image quality level not acceptable to the user" (hereinafter referred to as "image defects"). This makes it possible to repair abnormalities that cause image abnormalities while maintaining the image quality level desired by the user. Patent Document 1 proposes a technology that outputs a test chart to detect signs and predict the occurrence of image defects in order to determine in advance when to replace components. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Application Publication No. 2019-203997 Summary of the Invention [Problem to be solved by the invention]

[0004] However, the above-mentioned conventional technology has the following problem: In a configuration in which a test chart is used to predict image abnormalities, the test chart must be output during printing to perform the prediction process, which may reduce printing productivity.

[0005] The present invention has been made in consideration of at least one of the above problems, and provides a mechanism for appropriately diagnosing a precursor to an abnormality in an image forming apparatus while suppressing the processing load. [Means for solving the problem]

[0006] The present invention provides a diagnostic device, for example, comprising: a determining unit that determines whether to execute a precursor diagnosis process for detecting a precursor of an abnormality in an image forming unit when an image is formed on a recording medium by the image forming unit; If it is determined that the precursor diagnosis process should not be performed, the precursor diagnosis process is not performed, The system is characterized by comprising a diagnostic means which, when it is determined that the precursor diagnosis process should be performed, performs the precursor diagnosis process on a read image obtained by reading an image formed by the image forming means, and an automatic repair means which, when a precursor to the abnormality is detected by the diagnostic means, automatically repairs the image forming means before the precursor to the abnormality reaches a predetermined level of abnormality.

[0007] The present invention also provides, for example, an image forming apparatus, the image forming apparatus including: an image forming unit that forms an image on a recording medium; and a determining unit that, when the image is formed on the recording medium by the image forming unit, determines whether or not to execute a symptom diagnosis process that detects a symptom of an abnormality in the image forming unit. If it is determined that the precursor diagnosis process should not be performed, the precursor diagnosis process is not performed, The system is characterized by comprising a diagnostic means which, when it is determined that the precursor diagnosis process should be performed, performs the precursor diagnosis process on a read image obtained by reading an image formed by the image forming means, and an automatic repair means which, when a precursor to the abnormality is detected by the diagnostic means, automatically repairs the image forming means before the precursor to the abnormality reaches a predetermined level of abnormality.

[0008] The present invention also provides a diagnostic device, for example, comprising: a setting means for setting a number of sheets; a diagnostic means for executing a sign diagnostic process for detecting a sign of an abnormality in the image forming means on a read image obtained by reading an image formed by the image forming means each time the number of images formed on a recording medium by the image forming means reaches the number of sheets set by the setting means; and an automatic repair means for automatically repairing the image forming means when the sign of the abnormality is detected by the diagnostic means. When the previously detected abnormality precursor is close to the predetermined level, the diagnostic means advances the timing of executing the precursor diagnosis process. It is characterized by: [Effects of the Invention]

[0009] According to the present invention, it is possible to predict image abnormalities while suppressing the processing load without reducing the productivity of image formation. [Brief explanation of the drawings]

[0010] [Figure 1] FIG. 1 is a diagram showing an example of a network configuration including a printing system according to an embodiment. [Figure 2] FIG. 1 is a cross-sectional view showing an example of the hardware configuration of an image forming apparatus according to an embodiment. [Figure 3] FIG. 2 is a block diagram showing the internal configuration of an image forming apparatus, an external controller, and a client PC according to an embodiment. [Figure 4] 1 is a flowchart showing a procedure for precursor diagnosis according to an embodiment. [Figure 5] FIG. 10 is a diagram showing image abnormality levels according to an embodiment. [Figure 6] 10A and 10B are diagrams showing examples of diagnosable area settings for diagnosable items in RIP data according to an embodiment; [Figure 7] 10 illustrates a feature extractable map for each feature extractable item according to one embodiment. [Figure 8] 10 is a flowchart showing a procedure for executing a precursor diagnosis according to an embodiment; [Figure 9] FIG. 10 is a schematic diagram of a screen displaying the results of a sign diagnosis according to one embodiment. [Figure 10] FIG. 10 is a diagram showing the transition of the size and contrast of a premonition according to one embodiment. [Figure 11] FIG. 10 is a diagram showing a deterioration prediction table according to an embodiment. [Figure 12] 10 is a flowchart showing a procedure for symptom diagnosis when symptom diagnosis determination is performed after image reading according to an embodiment. [Figure 13] 10 is a flowchart showing a procedure for executing a sign diagnosis when a sign diagnosis determination is performed after image reading according to an embodiment. [Figure 14] FIG. 10 is a diagram illustrating an example of periodic precursor occurrence according to one embodiment. [Figure 15] FIG. 10 is a diagram showing an example of correspondence between parts and period information according to an embodiment. [Figure 16] FIG. 10 is a diagram illustrating an example in which a precursor occurs periodically across consecutive pages according to an embodiment. [Figure 17] 10 is a flowchart showing a procedure for symptom diagnosis when consecutive images are used as target images for symptom diagnosis according to one embodiment. [Figure 18] 10 is a flowchart showing a procedure for performing a sign diagnosis in parallel with an inspection process according to an embodiment. [Figure 19] FIG. 10 is a diagram showing an example of a screen displaying the results of the inspection process and the results of the symptom diagnosis side by side according to an embodiment. DETAILED DESCRIPTION OF THE INVENTION

[0011] Hereinafter, embodiments will be described in detail with reference to the accompanying drawings. Note that the following embodiments do not limit the scope of the invention claimed. Although multiple features are described in the embodiments, not all of these multiple features are necessarily essential to the invention, and multiple features may be combined arbitrarily. Furthermore, in the accompanying drawings, the same reference numerals are used to designate the same or similar components, and redundant explanations will be omitted.

[0012] First Embodiment <System configuration> A first embodiment of the present invention will be described below. An example of a network configuration including a printing system (image processing system) according to this embodiment will be described with reference to FIG. 1. As shown in FIG. 1, the printing system 100 includes an image forming apparatus 101 and an external controller 102. The image forming apparatus 101 and the external controller 102 are connected to each other via an internal LAN 105 and a video cable 106 so as to be able to communicate with each other. The external controller 102 is connected to a client PC 103 via an external LAN 104 so as to be able to communicate with each other. While this embodiment will be described taking as an example a configuration in which the image forming apparatus 101 and the external controller 102 are provided separately, this is not intended to limit the present invention. For example, the external controller 102 may be provided integrally with the image forming apparatus 101. In this case, the image forming apparatus 101 and the client PC 103 are connected so as to be able to communicate with each other.

[0013] The client PC 103 can issue a print instruction to the external controller 102 via the external LAN 104. A printer driver is installed in the client PC 103, and has the function of converting image data to be printed into a page description language (PDL) that can be processed by the external controller 102. A user who wishes to print can issue a print instruction via the printer driver from various applications installed on the client PC 103 by operating the client PC 103. The printer driver transmits PDL data, which is print data, to the external controller 102 based on the print instruction from the user. The PDL data is print data specified by the user, or data generated or selected within the client PC 103. Upon receiving the PDL data from the client PC 103, the external controller 102 analyzes and interprets the received PDL data. Based on the interpretation result, the external controller 102 performs rasterization processing to generate a bitmap image (print image data) with a resolution matching the image forming apparatus 101, and issues a print instruction by submitting a print job to the image forming apparatus 101.

[0014] Next, the image forming apparatus 101 will be described. The image forming apparatus 101 is connected to a plurality of devices with different functions and is configured to be capable of complex printing processes such as bookbinding. The image forming apparatus 101 has a printing unit 107 (image forming unit), an inserter 108, a symptom diagnosis unit 109, a stacker 110, and a finisher 111. Each module will be described below.

[0015] The printing unit 107 prints an image according to the contents of the print job and ejects the printed recording medium (paper, sheet, etc.). The printed recording medium ejected from the printing unit 107 is transported inside each device in the order of the symptom diagnosis unit 109, stacker 110, and finisher 111. In this embodiment, the image forming device 101 of the printing system 100 is an example of an image forming device, but the printing unit 107 included in the image forming device 101 may also be referred to as the image forming device. The printing unit 107 forms (prints) an image on the recording medium, which is fed and transported from a paper feed unit arranged below the printing unit 107, using toner (color material), which is the recording medium.

[0016] The inserter 108 is a device that inserts, for example, partition recording media to separate a series of recording media conveyed from the printing unit 107 at any desired position. The symptom diagnosis unit 109 is a device that detects "image abnormalities at a level of image quality acceptable to the user" (hereinafter referred to as "precursors") for the image forming apparatus 101 based on the printed recording media conveyed through the conveyance path after the images are printed by the printing unit 107. It also predicts "image abnormalities at a level of image quality unacceptable to the user" (hereinafter referred to as "image defects"). Specifically, the symptom diagnosis unit 109 reads the images printed on the conveyed printed recording media and performs a diagnosis based on the resulting read image. The symptom diagnosis detects precursors based on the difference in read signal values within the read image and predicts image defects based on the detected precursor information. Detailed processing by the symptom diagnosis unit will be described later. The use of the symptom diagnosis unit is not limited to the above example. The image forming apparatus 101 may also be equipped with an inspection system that inspects printed recording media for printing abnormalities and a diagnostic system that diagnoses abnormalities in the image forming apparatus 101 based on image defects.

[0017] The stacker 110 is a device capable of stacking a large number of printed recording media. The finisher 111 is a device capable of performing finishing processes such as stapling, punching, and saddle stitching on the conveyed printed recording media. The recording media processed by the finisher 111 are discharged to a predetermined discharge tray.

[0018] 1, an external controller 102 is connected to the image forming apparatus 101, but this embodiment can also be applied to a different configuration. For example, a configuration may be used in which the image forming apparatus 101 is connected to an external LAN 104, and print data is sent from a client PC 103 to the image forming apparatus 101 without going through the external controller 102. In this case, data analysis and rasterization of the print data are performed by the image forming apparatus 101.

[0019] <Hardware Configuration of Image Forming Apparatus 101> An example of the hardware configuration of the image forming apparatus 101 according to this embodiment will be described with reference to Fig. 2. A specific example of the operation of the image forming apparatus 101 will be described below with reference to Fig. 2. In the printing unit 107, various recording media (paper) are stored in the paper feed decks. During image formation, the uppermost recording media stored in each paper feed deck are separated one by one and fed to the conveying path 303.

[0020] Each of the image forming stations 304 to 307 includes a photosensitive drum (photoconductor) and forms a toner image on the photosensitive drum using toner of a different color. Specifically, the image forming stations 304 to 307 form a toner image using toner of yellow (Y), magenta (M), cyan (C), and black (K), respectively.

[0021] The toner images of each color formed in the image forming stations 304 to 307 are transferred onto the intermediate transfer belt 308 in order, superimposed on top of each other (primary transfer). The toner images transferred onto the intermediate transfer belt 308 are transported to a secondary transfer position 309 as the intermediate transfer belt 308 rotates. At the secondary transfer position 309, the toner image is transferred from the intermediate transfer belt 308 to a recording medium transported along a transport path 303 (secondary transfer). After the secondary transfer, the recording medium is transported to a fixing unit 311. The fixing unit 311 includes a pressure roller and a heating roller. As the recording medium passes between these rollers, heat and pressure are applied to the recording medium, thereby fixing the toner image to the recording medium. After passing through the fixing unit 311, the recording medium is transported along a transport path 312 to a connection point 315 between the printing unit 107 and the symptom diagnosis unit 109. In this manner, a color image is formed (printed) on the recording medium.

[0022] If further fixing processing is required depending on the type of recording medium, the recording medium that has passed through fixing unit 311 is guided to conveyance path 314 provided with fixing unit 313. Fixing unit 313 performs further fixing processing on the recording medium conveyed along conveyance path 314. The recording medium that has passed through fixing unit 313 is conveyed to connection point 315. Furthermore, if a double-sided printing operation mode is set, an image is printed on the first side, and the recording medium conveyed along conveyance path 312 or conveyance path 314 is guided to reversing path 316. The recording medium that has been reversed by reversing path 316 is guided to double-sided conveyance path 317 and conveyed to secondary transfer position 309. As a result, a toner image is transferred to the second side of the recording medium, which is opposite to the first side, at secondary transfer position 309. Thereafter, the recording medium passes through fixing unit 311 (and fixing unit 313), completing the formation of a color image on the second side of the recording medium.

[0023] After image formation (printing) in the printing unit 107 is completed, the printed recording medium is transported to the connection point 315 and then transported into the symptom diagnosis unit 109. The symptom diagnosis unit 109 includes image reading units 331 and 332, each having a contact image sensor (CIS), on a transport path 330 along which the printed recording medium from the printing unit 107 is transported. The image reading units 331 and 332 are positioned opposite each other across the transport path 330. The image reading units 331 and 332 are configured to read the top surface (first surface) and bottom surface (second surface) of the recording medium, respectively. Note that the image reading unit may be configured with a charge coupled device (CCD) or a line scan camera instead of a CIS, for example.

[0024] The precursor diagnosis unit 109 executes the precursor diagnosis process based on an instruction to execute the precursor diagnosis process. Specifically, the instruction to execute the precursor diagnosis process may be a method that determines whether to execute the precursor diagnosis process, such as a method of previously associating whether to execute the precursor diagnosis process with a print job or a method of pressing a precursor image diagnosis execution button at the start of the job. Alternatively, an automatic setting method, such as automatically setting the precursor image diagnosis to be executed immediately upon startup, may be used. When instructed to execute the precursor diagnosis process, the precursor diagnosis unit 109 determines whether images printed on printed recording media conveyed along the conveyance path 330 will be used for precursor diagnosis. Then, using scanned images of recording media determined to be subject to precursor diagnosis, the unit executes image precursor diagnosis process to determine whether a precursor has occurred in the image forming apparatus 101. Recording media determined not to be subject to precursor diagnosis are not used as target images for the image precursor diagnosis process. Specifically, when a printed recording medium being transported that has been determined to be a target for symptom diagnosis reaches a predetermined position, the symptom diagnosis unit 109 executes a reading process to read an image of the printed recording medium using the image reading units 331 and 332. Recording media that are not a target for diagnosis may be subjected to the same reading process as recording media that are a target for diagnosis, or may not be subjected to the reading process. Recording media that have passed the symptom diagnosis unit 109 are transported to the stacker 110 in order.

[0025] The stacker 110 includes a stack tray 341 as a tray on which printed recording media transported from the symptom diagnosis unit 109, which is disposed upstream in the transport direction of the printed recording media, are stacked. The printed recording media that have passed through the symptom diagnosis unit 109 are transported along a transport path 344 within the stacker 110. The printed recording media transported along the transport path 344 are guided to a transport path 345, whereby the printed recording media are stacked on the stack tray 341. Printed recording media that are transported in the stacker 110 without being stacked or ejected are transported via a transport path 348 to the subsequent finisher 111.

[0026] The stacker 110 further includes an inverting unit 349 for inverting the orientation of the printed recording medium being transported. The inverting unit 349 is used, for example, to make the orientation of the recording medium input into the stacker 110 the same as the orientation of the printed recording medium when it is stacked on the stack tray 341 and output from the stacker 110. Note that the inverting operation by the inverting unit 349 is not performed on printed recording media that are not stacked in the stacker 110 and are transported to the finisher 111.

[0027] The finisher 111 executes a finishing function specified by a user on a printed recording medium transported from the symptom diagnosis unit 109, which is disposed upstream in the transport direction of the printed recording medium. In this embodiment, the finisher 111 has finishing functions such as a staple function (one-point or two-point binding), a punch function (two-hole or three-hole), and a saddle stitch binding function. The finisher 111 includes two paper output trays 351 and 352. When a finishing process is not performed by the finisher 111, the printed recording medium transported to the finisher 111 is ejected to the paper output tray 351 via a transport path 353. When a finishing process such as stapling is performed by the finisher 111, the printed recording medium transported to the finisher 111 is guided to a transport path 354. The finisher 111 uses a finishing processing unit 355 to perform a finishing process specified by the user on the printed recording medium transported along the transport path 354, and ejects the printed recording medium on which the finishing process has been performed onto the paper ejection tray 352.

[0028] <Functional configuration> The functional configurations of the image forming apparatus 101, external controller 102, and client PC 103 according to this embodiment will be described with reference to Fig. 3. The printing unit 107 of the image forming apparatus 101 includes a communication I / F (interface) 201, a network I / F 204, a video I / F 205, a CPU 206, a memory 207, an HDD unit 208, and a UI display unit 225. The printing unit 107 further includes an image processing unit 202 and a print unit 203. These units are connected to each other via a system bus 209 so as to be able to send and receive data to and from each other.

[0029] The communication I / F 201 is connected to the symptom diagnosis unit 109, stacker 110, and finisher 111 via a communication cable 260. The CPU 206 communicates with each device via the communication I / F 201 to control the respective devices. The network I / F 204 is connected to the external controller 102 via the internal LAN 105 and is used for communicating control data and the like. The video I / F 205 is connected to the external controller 102 via a video cable 106 and is used for communicating data such as image data. Note that the printing unit 107 (image forming apparatus 101) and the external controller 102 may be connected only by the video cable 106, as long as the external controller 102 can control the operation of the image forming apparatus 101. The HDD unit 208 stores various programs and data. The CPU 206 controls the overall operation of the printing unit 107 by executing programs stored in the HDD unit 208. The HDD unit 208 also stores the total number of printed sheets, which is a count of how many sheets have been printed, and this is used to determine whether to perform automatic repair. The memory 207 stores programs and data required for the CPU 206 to perform various processes. The memory 207 operates as a work area for the CPU 206. The UI display unit 225 accepts various setting inputs and operation instructions from the user and is used to display various information such as setting information and the processing status of print jobs. For example, it accepts various instructions from the user, such as instructions to perform and set predictive diagnosis, and paper information settings.

[0030] The symptom diagnosis unit 109 includes a communication I / F 211, a CPU 214, a memory 215, an HDD unit 216, image reading units 331 and 332, and a UI display unit 241. These devices are connected via a system bus 219 so as to be able to send and receive data to and from each other. The communication I / F 211 is connected to the printing unit 107 via a communication cable 260. The CPU 214 performs communication necessary for controlling the symptom diagnosis unit 109 via the communication I / F 211. The CPU 214 controls the operation of the symptom diagnosis unit 109 by executing a control program stored in the memory 215. The memory 215 stores a control program for the symptom diagnosis unit 109. The image reading units 331 and 332 read images from a transported recording medium in accordance with instructions from the CPU 214. The CPU 214 diagnoses whether a symptom has occurred in the image forming apparatus 101 based on the read images for symptom diagnosis read by the image reading units 331 and 332.

[0031] The UI display unit 241 is used to display the results of the sign diagnosis, setting screens, etc. The operation unit also serves as the UI display unit 241 and is operated by the user to accept various instructions from the user, such as changing the settings of the sign diagnosis unit 109 and issuing instructions to perform image sign diagnosis. The HDD unit 216 stores various setting information and image data required for image sign diagnosis. The various setting information and image data stored in the HDD unit 216 can be reused.

[0032] The stacker 110 controls whether the printed recording medium conveyed along the conveyance path is discharged to a stack tray, discharged to an escape tray, or conveyed to a finisher 111 connected downstream in the conveyance direction of the printed recording medium. The finisher 111 controls the conveyance and discharge of the printed recording medium, and performs finishing processes such as stapling, punching, or saddle-stitching.

[0033] The external controller 102 includes a CPU 251, a memory 252, an HDD unit 253, a keyboard 256, a display unit 254, network I / Fs 255 and 257, and a video I / F 258. These devices are connected via a system bus 259 so that they can send and receive data to and from each other. The CPU 251 executes programs stored in the HDD unit 253 to control the overall operation of the external controller 102, such as receiving print data from the client PC 103, RIP processing, and sending print data to the image forming apparatus 101. The memory 252 stores programs and data required for the CPU 251 to perform various processes. The memory 252 operates as a work area for the CPU 251.

[0034] The HDD unit 253 stores various programs and data. The keyboard 256 is used for inputting operation instructions for the external controller 102 from the user. The display unit 254 is, for example, a display, and is used for displaying information about applications currently running in the external controller 102 and an operation screen. The network I / F 255 is connected to the client PC 103 via the external LAN 104 and is used for communicating data such as print instructions. The network I / F 257 is connected to the printing unit 107 via the internal LAN 105 and is used for communicating data such as print instructions. The external controller 102 is configured to be able to communicate with the printing unit 107, the symptom diagnosis unit 109, the stacker 110, and the finisher 111 via the internal LAN 105 and a communication cable 260. The video I / F 258 is connected to the printing unit 107 via the video cable 106 and is used for communicating data such as image data (print data).

[0035] The client PC 103 includes a CPU 261, a memory 262, an HDD unit 263, a display unit 264, a keyboard 265, and a network I / F 266. These devices are connected via a system bus 269 so that they can send and receive data to and from each other. The CPU 261 controls the operation of each device via the system bus 269 by executing a program stored in the HDD unit 263. This enables various processes to be performed by the client PC 103. For example, the CPU 261 generates print data and issues print instructions by executing a document processing program stored in the HDD unit 263. The memory 262 stores programs and data required for the CPU 261 to perform various processes. The memory 262 operates as a work area for the CPU 261.

[0036] The HDD unit 263 stores various applications such as a word processing program, programs such as a printer driver, and various data. The display unit 264 is, for example, a display, and is used to display information about applications running on the client PC 103 and an operation screen. The keyboard 265 is used to input operation instructions for the client PC 103 from the user. The network I / F 266 is communicably connected to the external controller 102 via the external LAN 104. The CPU 261 communicates with the external controller 102 via the network I / F 266.

[0037] <Predictive diagnosis processing> The processing procedure for the printing operation and the symptom diagnosis processing according to this embodiment will be described with reference to FIG. 4. Note that FIG. 4 shows the overall flow from the work before the symptom diagnosis starts to the execution of the symptom diagnosis and the execution of automatic repair. The symbol "S" in the description of the flowchart represents a step. This also applies to the following description of the flowcharts. The processing described below is executed by the CPU 206 of the printing unit 107, the CPU 214 of the symptom diagnosis unit 109, and the CPU 251 of the external controller 102. Here, the description will be given assuming that various CPUs cooperate to execute the processing described below, but it is also possible to have a single integrated CPU provided in the image forming apparatus execute all the processing.

[0038] In S401, the CPU 214 of the symptom diagnosis unit 109 receives a symptom diagnosis instruction from a user or service technician via the UI display unit 241, which also serves as the operation unit, and confirms the settings for the symptom diagnosis process. In this embodiment, a screen for receiving an instruction to start symptom diagnosis is displayed on the UI display unit 241, and upon receiving the start instruction, a predetermined level of image abnormality (image defect) is set as the symptom diagnosis setting. Note that the start instruction is not limited to the above example, and any instruction that indicates the execution of symptom diagnosis may be used. For example, a job and the execution of symptom diagnosis may be linked in advance, and upon receiving a symptom diagnosis execution job, it may be determined that an instruction to start symptom diagnosis has been issued. Here, a configuration in which an instruction is received via the UI display unit 241 of the symptom diagnosis unit 109 is described, but this is not intended to limit the present invention. Instructions may also be received from the client PC 103 via the external controller 102.

[0039] In this embodiment, the setting of the precursor diagnosis is performed by classifying the predetermined level for determining an image defect into nine levels based on the size and contrast of the image abnormality. Here, a case where the level for determining an image defect is selected according to user input will be described. FIG. 5 shows an example of the image abnormality levels. The image abnormality level 501 selected by the user as the criterion (predetermined level) for determining an image defect is set such that the lower the level, the larger the size 502 of the image abnormality and the higher the contrast 503. On the other hand, the higher the level, the smaller the size 502 of the image abnormality and the lower the contrast 503. Note that the setting of the image abnormality level is not limited to the above levels and can be set arbitrarily depending on the performance of the image forming apparatus, etc. Also, as long as it is a level for determining an image defect, it may be set by selecting only parameters such as size or contrast. Alternatively, a method of setting a numerical value instead of a level may be used. Once the setting of the precursor diagnosis is completed, the print job proceeds to print processing. As described above, according to this embodiment, multiple image abnormality levels are classified according to at least one parameter of the size and contrast of the abnormality.

[0040] In S402, the CPU 206 of the printing unit 107 accepts a print instruction from the client PC 103 or the external controller 102 and starts a print operation. Specifically, the CPU 251 of the external controller 102 performs PDL interpretation of the text, such as font type, size, and specified paper position, from the description in the PDF file based on the PDF print job accepted in S401. Next, the CPU 251 creates RIP data rasterized into a bitmap in accordance with the resolution setting interpreted in the PDL interpretation in S402. The CPU 251 links feature-extractable items from the RIP data. Details of the feature-extractable items will be described later.

[0041] The CPU 251 temporarily stores the created RIP data as a reference image in the HDD unit 253 of the external controller 102, linking it to a diagnosable item. The reference image stored in the HDD unit 253 is then sent to the symptom diagnosis unit 109 and stored in the HDD unit 216 of the symptom diagnosis unit 109. Furthermore, the CPU 251 transmits the RIP data from the video I / F 258 via the video cable 106 to the video I / F 205 of the printing unit 107. The CPU 206 of the printing unit 107 performs halftone processing on the RIP data received by the video I / F 205, and causes the printing unit 203 to print the image data after halftone processing.

[0042] In S403, the CPU 214 of the symptom diagnosis unit 109 determines whether the printed recording medium is to be subject to symptom diagnosis. As the number of printed sheets increases, the print quality gradually deteriorates, eventually changing to image defects, so symptom diagnosis does not need to be performed for each page. Therefore, the CPU 214 determines based on the judgment conditions whether the printed recording medium is a recording medium subject to symptom diagnosis or a recording medium not subject to symptom diagnosis. Details of the judgment conditions for symptom diagnosis subjects will be described later. If the printed recording medium is determined to be an image not subject to symptom diagnosis (No), proceed to S402. On the other hand, if the printed recording medium is determined to be a recording medium subject to symptom diagnosis (Yes), proceed to S404.

[0043] In S404, the CPU 214 performs a precursor diagnosis, which will be described later, and saves the results of this diagnosis in the HDD unit 216. In S405, the CPU 214 determines whether to perform automatic repair. In this embodiment, the timing for performing automatic repair is set to a predetermined number of sheets predicted in the precursor diagnosis, and the number of printed sheets saved in the HDD unit 208 is read out, and automatic repair is performed when the number of printed sheets reaches this predetermined number. Details of the automatic repair to be performed and the number of sheets to be set as the timing for performing automatic repair will be described later. If it is not the number of sheets to perform automatic repair (No), the process proceeds to S406. If it is the number of sheets to perform automatic repair (Yes), the process proceeds to S406, and automatic repair is performed.

[0044] In S406, the CPU 214 causes the printing unit 107 to perform automatic repair in accordance with the symptom diagnosis results stored in the HDD unit 216. After the automatic repair is performed, the process proceeds to S406. In S407, the CPU 206 of the printing unit 107 determines whether the job has ended. If the job is continuing (No in S406), the process proceeds to S402, and if the job has ended (Yes in S405), the process of this flowchart ends.

[0045] <Feature extraction items> Feature-extractable items according to this embodiment will be described with reference to FIGS. 6 and 7. FIG. 6 shows the feature extraction process according to this embodiment. FIG. 7 shows an example of a feature-extractable map for each feature-extractable item. In this embodiment, eight feature-extractable items are set, consisting of four colors, cyan, magenta, yellow, and black, and two combinations: whether an abnormality is occurring in a darker direction (positive contrast direction) or a lighter direction (negative contrast direction). Reference numeral 700 denotes a feature-extractable map (701 to 708) in which, for each feature-extractable item, pixels from which a feature can be extracted are represented as 1, and pixels from which a feature cannot be extracted are represented as 0.

[0046] For example, suppose an image anomaly occurs in image 605 printed from RIP data 601 including a monochrome (black and white) high-density black region 602, a low-density black region 603, and a white region 604. If a vertical streak 612 in the negative contrast direction occurs at main scanning position X1, the image anomaly is evident in high-density black region 606, but not in white region 608 or low-density black region 607. In other words, for the feature of negative black contrast, feature extraction is possible in locations where the black density is above a certain density. Therefore, map 708 of feature extractable items for the negative black contrast direction sets a diagnosable 1 to pixels where the black density exceeds 40% (615), and stores other pixels as 0 (616, 617), indicating that feature extraction is not possible.

[0047] Also, when vertical streaks 613 with a positive contrast in black occur at the position of the main scanning position X2, the vertical streaks become apparent in the white background portion 611 and the portion 610 with a low black density, but do not become apparent in the portion 609 with a high black density. That is, for the feature of the black contrast in the positive direction, feature extraction is possible in the portion where the black density is below a certain density. Therefore, the map 707 of the feature extraction possible items in the positive direction of the black contrast sets 1 that can be diagnosed for pixels with a black density of 60% or less (620, 621), and stores 0 as an undiagnosable area for other pixels (619).

[0048] And in the monochrome (for black and white printing) RIP data 601, it is impossible to extract features in the minus (paper white) direction of cyan, magenta, and yellow. Therefore, in the case of monochrome RIP data, the contrast minus directions of cyan, magenta, and yellow are stored as non-feature extraction possible items in the feature extraction possible maps 702, 704, and 706. Also, the feature extraction of cyan, magenta, and yellow in the plus direction is stored in the feature extraction possible maps 701, 703, and 705, assuming that it is only possible in the white background area 604 without black.

[0049] Note that the setting of diagnosable items is not limited to the above colors and contrast directions, and may be set by area or flatness. Furthermore, it is not limited to the shape of the map, and any method that can identify the possible area for the feature extraction items may be used. For example, instead of determining for each pixel, the RIP data may be divided into a plurality of blocks, and whether each block is diagnosable may be set.

[0050] <S404: Precursor Diagnosis Execution Process> The details of the sign diagnosis processing in S404 according to this embodiment will be described with reference to Fig. 8. Fig. 8 is a flowchart showing the steps of the image sign diagnosis processing executed by the sign diagnosis unit 109. The processing described below is executed by the CPU 214 of the sign diagnosis unit 109. Note that the processing may be executed by the CPU 206 of the printing unit 107 or the CPU 251 of the external controller 102, or may be executed in cooperation with these CPUs.

[0051] In S801, the CPU 214 executes a process of reading a recording medium that is the target of symptom diagnosis using the image reading units 331 and 332. The read image of the recording medium that is the target of diagnosis is saved in the HDD unit 216 of the symptom diagnosis unit 109 as the target image for symptom diagnosis. Once the target image for symptom diagnosis has been saved, the process proceeds to S802. In S802, the CPU 214 detects symptoms by comparing a reference image with the target image for symptom diagnosis to determine a symptom of an abnormality in the printing unit 107. In this embodiment, the reference image is compared with the target tomographic image for symptom diagnosis to obtain a difference value. The symptom diagnosis unit 109 may also include a correction unit that corrects the nonlinearity between the signal value and brightness of the target image for symptom diagnosis acquired by the image reading unit 331, and may correct the signal value of the symptom diagnosis image before obtaining the difference image data.

[0052] If the acquired difference value exceeds the threshold, the symptom diagnosis unit 109 determines that a difference exists and sets 1 to the difference image data. On the other hand, if the difference value is below the threshold, it sets 0 to the difference image data. In this embodiment, the threshold value is a value that is even smaller in size and lower in contrast than the level set in S401. For example, if level 7 (510: size 400 μm, contrast 30%) is set as an image defect in S401, level 9 (504: size 200 μm, contrast 10%) is set as the detection threshold. The symptom diagnosis unit 109 saves the difference image data, which is binary data indicating the presence or absence of a difference, in the HDD unit 216 and proceeds to S803.

[0053] When the creation of the differential image data is completed, in S803 the CPU 214 determines whether or not a precursor has occurred. This determination is made based on whether or not data containing 1 exists in the differential image data. If the determination result indicates that a precursor has not occurred (No in S803), the CPU 214 ends the processing of this flowchart. On the other hand, if the determination result indicates that a precursor has occurred (the differential image data contains 1) (Yes in S803), the CPU 214 proceeds to S804.

[0054] In S804, the CPU 214 extracts features for identifying parts in the printing unit 107 where a warning sign of an abnormality is occurring from the target image data for warning sign diagnosis, the difference image data, and the diagnosable items linked to the reference image. The CPU 214 extracts difference features from the target image for warning sign diagnosis and the diagnosable items corresponding to the difference areas determined to have a difference from the difference image data in S802. In this feature extraction process, for example, color material information and contrast information are obtained from the difference image according to the diagnosable items. The color material information indicates which color (yellow, magenta, cyan, or black) is causing the warning sign. The contrast information indicates, as a positive or negative numerical value, whether the contrast of the warning sign is in the positive or negative direction. Here, the CPU 214 does not extract as features colors not set in the diagnosable items determined from the RIP data, or the positive or negative contrast directions.

[0055] Furthermore, the CPU 214 acquires size information such as the width (size in the main scanning direction) and height (size in the sub-scanning direction) of the precursor, and shape information such as the shape of a dot (dot), vertical streak, or horizontal streak. In this embodiment, an example is described in which the shape information is acquired based on the aspect ratio of the width and height of the acquired size information. Specifically, if the aspect ratio calculated by dividing the width by the height exceeds a predetermined threshold, the shape is determined to be a horizontal streak. If the aspect ratio is equal to or less than the threshold, the shape is determined to be a vertical streak, and if it does not fit either category, it is determined to be a dot. Note that the acquisition of shape information is not limited to the above example, and any method can be used to identify the shape of the precursor, such as a dot, horizontal streak, or vertical streak. For example, a width equal to or greater than a threshold may be determined to be a horizontal streak, a height equal to or greater than a threshold may be determined to be a vertical streak, and anything else may be determined to be a dot. Other characteristics include coordinate information indicating the position in a direction perpendicular to the transport direction of the recording medium within the printing unit 107, and periodic information indicating that precursors of similar characteristics occur periodically in the transport direction of the recording medium within the printing unit 107.

[0056] In S805, the CPU 214 identifies the part in the printing unit 107 or the image reading unit 331 that is the cause of the sign, based on the feature information of the differential region obtained in S804. From the differential region, combinations of the same color with high similarity are selected, and it is possible to identify which part is causing the sign based on the periodic information of the selected combination. In this embodiment, a case will be described in which the determination of combinations with high similarity is obtained using a known template matching technique.

[0057] The images of the precursors are compared using template matching, and the highest value is determined to be the similarity between the precursors. The precursors whose obtained similarity is equal to or greater than a predetermined threshold are determined to be a highly similar combination. The similarity determination method is not limited to the above, and any method for determining whether the precursors are similar to each other may be used. For example, a method for determining the similarity between images using machine learning or a method for obtaining similarity by comparing feature amounts or feature points of precursor images may be used. The CPU 214 reads the current number of prints stored in the HDD unit 208, associates the extracted features with the occurring parts, and stores them in the HDD unit 216, and proceeds to S806.

[0058] In S806, the CPU 214 predicts the number of prints that will result in image defects based on the causative parts identified in S805, the size and contrast of the precursor, characteristic information of past precursors stored in the HDD unit 216, and a deterioration level table for each part. The prediction method will be described in detail later. The CPU 214 saves the predicted number of prints in the HDD unit 216 and proceeds to S807.

[0059] In S807, the CPU 214 determines whether automatic repair is possible. Cases that cannot be automatically repaired include those that require user action, such as cleaning dirt from the reading glass surfaces of the image reading units 331 and 332 of the symptom diagnosis unit 109 or adjusting the recording medium to be used, or those that require service personnel action, such as replacing parts. Cases that cannot be automatically repaired also include those that deal with reading abnormalities in the image reading units and fibers or foreign matter that are present on the recording medium before image formation. If automatic repair is not possible, the process proceeds to S808.

[0060] On the other hand, an item that can be automatically restored is an action that can be automatically restored by the printing unit 107, such as cleaning the wire or grid of the corona charger of the photosensitive drum provided in the image forming stations 304 to 307 of the printing unit 107 using a charger cleaning mechanism (not shown). If an item can be automatically restored, the process proceeds to S809.

[0061] In step S808, the CPU 214 displays on the UI display unit 241 of the symptom diagnosis unit 109 that automatic repair is not possible and that action is required, and then ends the processing of this flowchart. Figure 9 shows an example of the display of the diagnosis results when action is required. The result display, as shown in 901, shows the number of remaining pages until the image defect occurs, calculated by subtracting the current number of printed pages from the number of printed pages at which the image defect is predicted to occur, which is stored in the HDD unit 216. Based on the diagnosis results, necessary action steps 902, such as "cleaning the reading glass surface" or "notifying a service technician," are also displayed. The notification of the action step is not limited to the above, and any method that allows the results to be confirmed may be used. The diagnosis result screen may be displayed on the display unit 264 of the client PC 103, the display unit 254 of the external controller 102, or the UI display unit 225 of the printing unit 107. The notification content may also be displayed by displaying whether or not a symptom was detected alongside detailed content, or by displaying a timeline or images side by side.

[0062] On the other hand, in step S809, the CPU 214 stores the details of automatic repair in the HDD unit 216, linked to the number of sheets up to the image defect stored in the HDD unit 216, and ends the processing of this flowchart. For example, if a warning sign has occurred in the corona charger of the photosensitive drum, cleaning of the corona charger wire is stored as the details of automatic repair.

[0063] <Setting the criteria for predictive diagnosis> The conditions for determining whether a printed recording medium is a target for symptom diagnosis in S403 of FIG. 4 will be described. Because the print quality gradually deteriorates toward image defects as the number of printed sheets increases, symptom diagnosis does not necessarily need to be performed on every page. Therefore, in this embodiment, the timing for performing symptom diagnosis is determined. For example, when the symptom diagnosis count stored in the HDD unit 216 reaches a predetermined number of printed sheets, such as every 200 sheets, the image is determined to be a target for symptom diagnosis. If the symptom diagnosis count is determined not to be a target for symptom diagnosis (No in S403), the count is incremented by one and stored in the HDD unit 216, thereby increasing the count to the number of sheets that meet the symptom diagnosis target criteria. If the number of sheets that meet the symptom diagnosis target criteria and the symptom diagnosis count are equal, the symptom diagnosis process S404 is executed. When the process is completed, the symptom diagnosis count is reset (to 0) and stored in the HDD unit 216. Note that the number of sheets that meet the criteria for symptom diagnosis is not limited to a predetermined number, but may be a number set by the user. Furthermore, the criteria for determining whether to perform a precursor diagnosis are not limited to the number of printed sheets, but may be any criteria that allows for tracking of precursors without reducing productivity. For example, the next precursor diagnosis may be started once the diagnostic results of the precursor diagnosis are obtained. This is effective when the execution time of the precursor diagnosis process is longer than the time it takes to print on one sheet of recording medium.

[0064] <Predicted number of image defects> 10 and 11, the prediction of the number of prints that will result in an image defect in S806 will be described. In this embodiment, the precursor diagnosis unit 109 predicts the number of prints that will result in an image defect based on the size and contrast information of the precursor for the same part that was saved in the HDD unit 216 during a previous precursor diagnosis. Here, a method for predicting the number of prints that will result in an image defect from the changes in the size and contrast of the precursor that has occurred will be described. 1001 indicates the size of the precursor on the vertical axis and the number of prints on the horizontal axis. 1012 indicates the contrast of the precursor on the vertical axis and the number of prints on the horizontal axis.

[0065] For example, as shown in Figure 10, assume that the current precursor diagnosis result is that 300 sheets have been printed, precursor B for the black drum has occurred, and the size is 275 μm and the contrast is 20%. If the previous precursor diagnosis saved information for precursor A, which showed 100 sheets printed, with the black drum having a size of 270 μm and a contrast of 19%, then after 200 sheets of printing, the size has deteriorated by 5 μm and the contrast by 1%. This explains the predicted number of defective images when deterioration is proportional to the number of sheets printed.

[0066] If the image abnormality level set in S401 is level 7 (506), a size of 400 μm and a contrast of 30% are the criteria for determining image defects. Therefore, from the perspective of size, based on 1001, it can be predicted that the image will deteriorate to image defect C after 5,000 sheets. From the perspective of contrast, based on 1012, it can be predicted that the image will deteriorate to image defect D after 2,000 sheets. When determining the predicted number of sheets until either size or contrast reaches the image defect level (level 7), the contrast is determined to be image defective after 2,000 sheets, which is less than the predicted number of sheets from the perspective of size (5,000 sheets). Therefore, the predicted result until image defect occurs is determined to be 2,000 sheets. Therefore, since the current number of printed sheets is 300, it can be predicted that the image may deteriorate to the image abnormality level after 2,000 sheets, that is, 2,300 sheets. The CPU 214 saves the predicted number of printed sheets until image defect occurs in S806 in the HDD unit 216 and proceeds to S807.

[0067] Alternatively, the number of sheets and the degradation rate, which indicate the degree of degradation for each part in terms of size and contrast, may be stored in advance, and the data may be acquired by referencing these. The case where a degradation prediction table for each part is stored in advance will be described. Fig. 11 shows an example of a degradation prediction table 1100. The degradation prediction table 1100 stores information on how much size 1102 and contrast 1103 will deteriorate per 100 sheets for a part 1101.

[0068] For example, consider a black drum with a 275 μm size and 20% contrast, and the image failure level is set to level 7 (506). In this case, the image failure level of 400 μm size and 30% contrast occurs when the size is 400 μm - 275 μm = 125 μm and the contrast is 30% - 20% = 10%. The photoconductor drum deteriorates by 2.5 μm size and 0.5% contrast per 100 sheets. Therefore, the number of sheets until the image failure occurs is 125 μm ÷ 2.5 μm × 100 sheets = 5,000 sheets in terms of size, and 10% ÷ 0.5% × 100 sheets = 2,000 sheets in terms of contrast. To determine the predicted number of sheets until either the size or contrast reaches the image failure level, as in Figure 10, it can be determined that the image failure level will be reached in 2,000 sheets. In other words, if the current number of printed sheets is 300, it can be predicted that the image quality will reach the level of a defective image when the number of printed sheets reaches 2300 sheets after 2000 sheets. The prediction method only requires predicting how many sheets will need to be printed before the image quality reaches the level of a defective image based on the detected precursor. Prediction can be made based on not only the past one time but also multiple past trends. Alternatively, a method can be used in which the precursor image, feature values, and image abnormality level are input to predict how many sheets will need to be printed before the image quality becomes defective using machine learning.

[0069] As described above, the diagnostic device according to this embodiment determines whether to execute a precursor diagnosis process to detect a precursor to an abnormality in the image forming device when an image is formed on a recording medium by the image forming unit (printing unit). Furthermore, when it is determined that a precursor diagnosis process should be executed, the diagnostic device executes a precursor diagnosis process on the read image obtained by reading the image formed by the image forming unit using the reading unit. If a precursor to an abnormality is detected, the diagnostic device automatically repairs the image forming unit before the precursor to the abnormality reaches a predetermined level. Thus, according to this embodiment, by determining whether an image on a printed recording medium is a target image for precursor diagnosis and then executing the precursor diagnosis, it is possible to perform a precursor diagnosis with reduced processing load without reducing productivity. In other words, this embodiment provides a mechanism for appropriately diagnosing precursors to an abnormality in an image forming device while reducing the processing load. <Variation 1> The present invention is not limited to the above embodiment and can be modified in various ways. Below, a first modification of the first embodiment will be described. In the first embodiment, a printed recording medium is determined whether it is a recording medium for which a sign diagnosis is to be performed in the sign diagnosis execution determination step (S403), and the recording medium for which a sign is to be performed is read in step S802 during sign diagnosis execution step (S404). However, a configuration may also be adopted in which, after the printed recording medium is read, it is determined whether the read image is an image for which a sign diagnosis is to be performed.

[0070] <Precursor diagnosis processing> The processing procedure for the symptom diagnosis process in this modified example will be described with reference to Figures 12 and 13. In this modified example 1, a read image is determined to be a target image for symptom diagnosis, and symptom diagnosis is then performed. The same step numbers are used for processes similar to those in the flowchart of Figure 4, and descriptions thereof will be omitted. The processes described below are performed by the CPU 206 of the printing unit 107, the CPU 214 of the symptom diagnosis unit 109, and the CPU 251 of the external controller 102. Here, various CPUs are described in cooperation to perform the processes described below, but a single integrated CPU provided in the image forming apparatus may also perform all processes.

[0071] When printing is executed in S402, the CPU 214 of the symptom diagnosis unit 109 executes a process of reading the printed recording medium in S1201. The read image is saved in the HDD unit 216 of the symptom diagnosis unit 109. Once the read image is saved, the process proceeds to S1202. In S1202, the CPU 214 determines whether the read image is to be subject to symptom diagnosis. Specifically, the CPU 214 determines whether the read image is a subject image for symptom diagnosis based on the criteria for determining subject to symptom diagnosis. If it is subject to symptom diagnosis (Yes in S1202), the process proceeds to S1203; if it is not subject to symptom diagnosis (No in S1202), the process proceeds to S405.

[0072] The detailed processing procedure of the precursor diagnosis execution process (S1203) will be described with reference to Figure 13. The processing described below is executed, for example, by the CPU 214 of the precursor diagnosis unit 109. Note that it may also be executed by the CPU 206 of the printing unit 107 or the CPU 251 of the external controller 102, or in cooperation with these CPUs. Processes similar to those in the flowchart of Figure 8 are assigned the same step numbers, and descriptions thereof will be omitted.

[0073] In S1301, the CPU 214 of the symptom diagnosis unit 109 reads out the scanned image stored in the HDD unit 216 in S1201 as a target image for symptom diagnosis. In S802, the CPU 214 executes symptom diagnosis processing using the read target image. The subsequent processing is the same as in the flowchart of FIG. 8, and therefore description thereof will be omitted.

[0074] <Variation 2> Next, a second modification of the first embodiment will be described. In the first embodiment, a set number of sheets is used as a condition for determining whether a precursor diagnosis target is to be performed. However, the present invention does not intend to limit the condition for determining whether a precursor diagnosis target is to be performed to the above. Here, an example will be described in which the condition for determining whether a precursor diagnosis target is to be performed is other than the set number of sheets.

[0075] If a previously detected precursor is close to the level of an image defect, a more accurate prediction can be achieved by advancing the timing of the precursor diagnosis and updating the precursor transitions 1001 and 1012 more precisely. To achieve this, a configuration may be adopted in which the number of images, which is the determination condition for precursor diagnosis, is reduced according to the size or contrast of the previously detected precursor. A more accurate prediction can be achieved by advancing the timing of the precursor diagnosis and updating the precursor transitions 1001 and 1012 more precisely. For example, if the number of images remaining until the image defect level predicted in S807 is close to the image defect level, such as 300 images, in this modified example, a more accurate prediction can be achieved by changing the next precursor diagnosis from 200 images later to 50 images later.

[0076] Furthermore, if the speed of deterioration leading to image defects is known in advance based on the precursor, the timing of precursor diagnosis may be changed according to the type of precursor detected. Specifically, if a precursor for a part with a fast deterioration rate is detected in the deterioration prediction table 1100 shown in FIG. 11, the number of sheets of judgment conditions for the precursor diagnosis target may be reduced, and the timing of precursor diagnosis may be advanced to track the precursor. For example, the size deterioration rate for the developing unit per 100 sheets is 2 μm, while the size deterioration rate for the photosensitive drum per 100 sheets is 2.5 μm, which is large and therefore tends to deteriorate quickly. Therefore, if a precursor for the photosensitive drum is detected, the number of sheets of judgment conditions for the precursor diagnosis target may be reduced, and the timing of precursor tracking (precursor diagnosis) may be advanced to enable diagnosis according to the degree of deterioration of the precursor.

[0077] Furthermore, the criteria for determining whether a symptom is to be diagnosed need not be the entire page, but rather a portion of the page, such as a range limited by main scanning position or a range in which features can be extracted from feature-extractable items. Symptoms are characterized by periodically occurring in the same color at the same main scanning position as the symptom-occurring part. Figure 14 shows an example of occurrence at the same main scanning position. For example, suppose a periodicity correspondence table that corresponds parts with periodicity information has been prepared in advance. Figure 15 shows an example of a periodicity correspondence table.

[0078] Assume that a scratch has occurred in the development unit at the main scanning position 1401, and periodic precursor 1407 has been detected in image 1402, which is the target of precursor diagnosis. The precursor occurs every 37 mm at the main scanning position corresponding to the position 1401. In image 1403, which is the target of precursor diagnosis after 200 sheets of RIP data 601 have been printed, the precursor also occurs in range 1408 of the same main scanning position. Therefore, range 1408, which is narrowed down by the main scanning position, rather than the entire image, may be used as the criteria for determining the target of precursor diagnosis. Furthermore, in image 1403, according to the feature extractable map 707 for the positive direction of black, feature extraction is not possible in area 1404 for abnormalities in the positive direction of black, but is possible only in areas 1405 and 1406. Therefore, the feature extractable areas of the map of feature extractable items may be used as the criteria for determining the target of precursor diagnosis.

[0079] These conditions may be combined to include the "number of sheets" and the "area where feature extraction is possible with the feature extractable item." For example, the conditions for a precursor diagnosis target are that the set number of sheets is 200 and that the period occurrence position is a location where feature extraction is possible with the feature extractable item. When the precursor count number reaches 200, if the period occurrence position is in an area where feature extraction with the feature extractable item is not possible, the precursor diagnosis target is determined not to be a target (No in S403), and the precursor count number is not changed and processing proceeds to the next step. The precursor count number for the next page is also 200, which is equal to the set number, so whether or not a precursor diagnosis target is determined based on whether feature extraction is possible with the feature extractable item at the period occurrence position. The subsequent processing is similar to that of the above embodiment, and therefore description thereof will be omitted.

[0080] <Second embodiment> The following describes a second embodiment of the present invention. In the first embodiment, precursor diagnosis was performed using a single target image for precursor diagnosis. In the present embodiment, however, a precursor diagnosis is performed using multiple consecutive target images for precursor diagnosis. In the first embodiment, when performing the precursor diagnosis process, the part in which the precursor occurred was identified using the precursor features detected from a single target image for precursor diagnosis. However, depending on the part, precursors may occur periodically across multiple pages. For example, FIG. 16 shows an example in which precursors occur periodically across multiple pages when parts correspond to periodic information as shown in FIG. 15.

[0081] In the example of Figure 16, when printing is performed on an A3 recording medium with a length of 420 mm in the transport direction, the development unit has a periodic cycle of 37 mm, so multiple precursors occur periodically in the transport direction on a single sheet. However, because the photosensitive drum 307 has a periodic cycle of 264 mm, only one precursor 1603 occurs on a single page 1602, so feature extraction S805 may not be able to extract periodic features. Furthermore, the next page 1604 also has a periodic precursor 1605, so if 1603 and 1605 are included, periodic features can be extracted in feature extraction S805. Therefore, in this embodiment, we will describe a case where precursor feature extraction is performed on multiple consecutive pages, such as 1602 and 1604, rather than the single page 1602, as the diagnostic target images.

[0082] The detailed processing procedure of the precursor diagnosis execution process of S404 in this embodiment will be described with reference to Figure 17. The processing described below is executed, for example, by the CPU 214 of the precursor diagnosis unit 109. Note that it may also be executed by the CPU 206 of the printing unit 107 or the CPU 251 of the external controller 102, or in cooperation with these CPUs. Processing similar to that in the flowchart of Figure 8 is assigned the same step numbers, and description thereof will be omitted.

[0083] First, in the symptom diagnosis target determination S403, the CPU 214 determines that a specified number of consecutive images, rather than one, are the target for symptom diagnosis. In this embodiment, we will describe a case where the number of consecutive images is five, and the determination condition for symptom diagnosis targets is set to execute symptom diagnosis every 100 images. The determination condition for symptom diagnosis targets is to execute symptom diagnosis for five consecutive images every 100 images. In other words, not only the 100th symptom count image stored in the HDD unit 216, but also the 100th to 104th consecutive images are determined to be diagnostic target images.

[0084] If a sign is detected in S802, the CPU 214 determines in S1701 whether the sign detection process S802 has been completed for the specified number of consecutive images (5). If it has been completed (Yes in S1701), the process proceeds to S803, and if the sign detection process S802 has not been completed for all consecutive sign target images (No in S1701), the process returns to S801.

[0085] In S803, the CPU 214 determines whether a precursor has occurred. If a precursor has occurred (Yes in S803), the process proceeds to S1702. If a precursor has not occurred (No in S803), the process of this flowchart ends.

[0086] In S1702, the CPU 214 extracts the characteristics of a precursor when a precursor occurs. This embodiment describes the extraction of periodic characteristics, which differs from the first embodiment. The CPU 214 extracts periodic characteristics based on the coordinates of the precursor and the continuity of printing. Specifically, if a similar precursor exists not only within the page but also in subsequent pages at a later period in the transport direction, the CPU 214 determines that the precursors have periodic characteristics. Once extraction of all precursor characteristics, including periodic information, is complete, the process proceeds to S805.

[0087] As described above, the diagnostic device according to this embodiment performs diagnosis using images formed successively on a plurality of recording media as diagnostic target images. In this way, by performing symptom diagnosis using a plurality of consecutive diagnostic target images instead of a single diagnostic target image, it becomes possible to diagnose symptoms even for parts where symptoms occur periodically across multiple images.

[0088] <Third embodiment> A third embodiment of the present invention will be described below. In this embodiment, a case where the symptom diagnosis is linked to an inspection system will be described. This embodiment can be implemented in combination with the first and second embodiments, but the effects of the present invention are not limited to the examples of the first and second embodiments. For example, in conjunction with an inspection system that detects abnormalities in scanned images of printed materials, symptom diagnosis may be performed by using a portion of the scanned image inspected by the inspection system as a symptom diagnosis image. In this embodiment, an example will be described in which the inspection system is executed in parallel with the symptom diagnosis process by the CPU 214 of the symptom diagnosis unit 109, and the symptom diagnosis process is performed using a portion of the scanned image read by the image reading units 331 and 332.

[0089] <Precursor diagnosis processing> A detailed processing procedure of the symptom diagnosis processing in this embodiment will be described with reference to FIG. 18. The configuration of the printing system according to this embodiment and the flow of the symptom diagnosis processing flow are the same as those in the first embodiment, and therefore a description thereof will be omitted. The same step numbers are used for processing that is the same as that in the flowcharts of FIG. 4 and FIG. 12, and a description thereof will be omitted. The processing described below is executed by the CPU 206 of the printing unit 107, the CPU 214 of the symptom diagnosis unit 109, and the CPU 251 of the external controller 102. Here, the processing described below is executed by various CPUs working together, but it is also possible to have a single integrated CPU provided in the image forming apparatus execute all processing.

[0090] In S1801, the CPU 214 of the precursor diagnosis unit 109 sets the image defect level. In this embodiment, image abnormalities at the image defect level are detected as inspection failures, and image abnormalities that pass inspection (not reaching the image defect level) are used as precursors to diagnose the location where the precursor has occurred. Specifically, a case will be described in which level 7 (510: size 300 μm, contrast 30%) of the nine levels of abnormality in FIG. 5 is set as the image defect level. In this case, precursor detection is performed at level 9 (504: size 100 μm, contrast 10%), which has a smaller size and lower contrast than the image defect level. Note that the setting of the precursor level for detecting an image defect is not limited to a level setting. Any method may be used as long as the user can set the degree of degradation that is not acceptable as an image defect, such as by specifying a numerical value or selecting an image.

[0091] When the scanned image is acquired in S1201, in parallel with the symptom diagnosis processing in S1202 and S1203, the CPU 214 executes an inspection processing in S1802 to detect image defects using the scanned image acquired in S1201. Specifically, the CPU 214 reads the scanned image acquired in S1201 from the HDD unit 216 and detects image abnormalities at the image defect level set in S1801.

[0092] Next, in S1803, the CPU 214 displays the inspection results on the UI display unit 241 of the symptom diagnosis unit 109. Figure 19 is an example of an image displaying the results of the inspection process and the symptom diagnosis process. If the CPU 214 detects an image defect, it displays this in the inspection result 1901 of the UI display unit 241 of the symptom diagnosis unit 109, and if no defect is detected, it displays ``no problem'' in the inspection result 1901 of the UI display unit 241, as shown in the result screen 1900. After notifying the detection result, the process proceeds to S405.

[0093] In parallel, in S1202, the CPU 214 determines whether the scanned image used in the inspection process of S1802 is a target image for symptom diagnosis. If it is determined to be a target image for symptom diagnosis, the process proceeds to S1203, where symptom diagnosis process is executed. On the other hand, if it is determined to be a non-target image for symptom diagnosis, the process proceeds to S405. In S1203, the CPU 214 executes symptom diagnosis execution process on the target image for symptom diagnosis, and displays a symptom diagnosis process execution result screen 1910 on the UI display unit 241 alongside the inspection process result 1901 as a symptom diagnosis result 1902. In this embodiment, if there are no symptoms (No in S803), "No symptoms" is displayed on the UI display unit 241 before proceeding. Furthermore, if there are symptoms, in S809 and S808, the number 1903 predicted in S806 is displayed as a symptom diagnosis result 1902 on the UI display unit 241 before proceeding. If automatic repair is not possible (No in S807), a solution 1904 is also displayed in S808.

[0094] The notification of the results of the inspection process and the symptom diagnosis process is not limited to the above, and any method that allows the results to be confirmed may be used. These result screens may be displayed on the display unit 264 of the client PC 103, the display unit 254 of the external controller 102, or the UI display unit 225 of the printing unit 107. Alternatively, a display that switches between the inspection results and the symptom diagnosis results may be used. When the notification of the results is completed in No. of S803, S809, or S808, the process proceeds to S405.

[0095] As described above, the diagnostic device according to this embodiment diagnoses (inspects) an image for abnormalities when an image is formed on a recording medium by the image forming unit, regardless of the result of the determination as to whether or not to execute the precursor diagnosis process. This makes it possible to use a portion of the scanned image inspected in the inspection process to set the precursor detection level in accordance with the inspection level, thereby utilizing the inspection image to diagnose precursors in accordance with the user's image abnormality level.

[0096] The disclosure of this specification includes the following diagnostic device, its control method, program, and image forming device. (Item 1) 1. A diagnostic device comprising: a determining means for determining whether or not to execute a symptom diagnosis process for detecting a symptom of an abnormality in the image forming means when the image forming means forms an image on a recording medium; a diagnostic means for executing the precursor diagnosis process on a read image obtained by reading an image formed by the image forming means, when it is determined that the precursor diagnosis process should be executed; an automatic repair means for automatically repairing the image forming means before the sign of the abnormality reaches a predetermined level when the sign of the abnormality is detected by the diagnostic means; A diagnostic device comprising: (Item 2) The diagnostic means comprises: an extraction means for extracting a feature quantity for identifying in which part of the image forming means the symptom of the abnormality has occurred, from the detected symptom of the abnormality; an identifying unit that identifies a part of the image forming unit in which a sign of the abnormality occurs based on the extracted feature amount; 2. The diagnostic device according to item 1, comprising: (Item 3) 3. The diagnostic device according to item 2, wherein the feature amount includes size information and shape information of the abnormality precursor, and periodic information of occurrence of the abnormality precursor. (Item 4) The diagnostic means further comprises: 4. The diagnostic device according to item 2 or 3, further comprising a prediction means for predicting a timing at which the detected sign of the abnormality will reach the predetermined level of abnormality based on the extracted feature amount. (Item 5) 5. The diagnostic device according to item 4, wherein the prediction means predicts the timing at which the detected precursor to the abnormality will reach the predetermined level of abnormality based on the feature amount and the identified parts. (Item 6) 6. The diagnostic device according to item 4 or 5, wherein the prediction means predicts the number of images formed on recording media by the image forming means as the timing when the detected precursor to the abnormality reaches the predetermined level of abnormality. (Item 7) 7. The diagnostic device according to any one of items 4 to 6, wherein the diagnostic means displays the diagnostic result of the precursor along with the timing at which the predetermined level of abnormality is reached on a display unit. (Item 8) The diagnostic device described in any one of items 1 to 7 is characterized in that the judgment means judges to execute the precursor diagnosis process each time the image formation on the recording medium by the image forming means reaches a predetermined number of sheets, or when the precursor diagnosis process currently being executed is completed. (Item 9) 9. The diagnostic device according to item 8, wherein the predetermined number is set according to a user input. (Item 10) A diagnostic device described in any one of items 2 to 9, characterized in that the judgment means makes a judgment to advance the timing of executing the precursor diagnosis process when the precursor to the abnormality previously detected is close to the predetermined level. (Item 11) The diagnostic device according to any one of items 2 to 7, wherein the determination means determines whether or not to execute the precursor diagnosis process using different determination conditions for each of the identified parts. (Item 12) 12. The diagnostic device according to any one of items 2 to 11, further comprising a setting means for setting a level selected from a plurality of image abnormality levels in response to a user input as the predetermined level of abnormality. (Item 13) Item 13. The diagnostic apparatus according to item 12, wherein the levels of the plurality of image abnormalities are classified by at least one parameter of the size and contrast of the abnormality. (Item 14) 14. The diagnostic device according to any one of items 2 to 13, wherein the diagnostic means performs diagnosis using images formed successively on a plurality of recording media as images to be diagnosed. (Item 15) The diagnostic device described in any one of items 2 to 14, characterized in that when an image is formed on a recording medium by an image forming means, the diagnostic means diagnoses abnormalities in the image regardless of the judgment result by the judgment means. (Item 16) 16. The diagnostic device according to any one of items 2 to 15, further comprising the reading means for reading a recording medium on which an image has been formed by the image forming means. (Item 17) A method for controlling a diagnostic device, comprising: a determining step of determining whether or not to execute a symptom diagnosis process for detecting a symptom of an abnormality in the image forming means when the image forming means forms an image on a recording medium; a diagnostic step of, when it is determined that the precursor diagnosis process is to be performed, performing the precursor diagnosis process on a read image obtained by reading the image formed by the image forming means with a reading means; an automatic repair step of automatically repairing the image forming means before the abnormality precursor reaches a predetermined level when the abnormality precursor is detected in the diagnosis step; A method for controlling a diagnostic device, comprising: (Item 18) A program for causing a computer to execute each step of a method for controlling a diagnostic device, the control method comprising: a determining step of determining whether or not to execute a symptom diagnosis process for detecting a symptom of an abnormality in the image forming means when the image forming means forms an image on a recording medium; a diagnostic step of, when it is determined that the precursor diagnosis process is to be performed, performing the precursor diagnosis process on a read image obtained by reading the image formed by the image forming means with a reading means; an automatic repair step of automatically repairing the image forming means before the abnormality precursor reaches a predetermined level when the abnormality precursor is detected in the diagnosis step; A program comprising: (Item 19) An image forming apparatus, an image forming means for forming an image on a recording medium; a determining means for determining whether or not to execute a symptom diagnosis process for detecting a symptom of an abnormality in the image forming means when an image is formed on a recording medium by the image forming means; a diagnostic means for executing the precursor diagnosis process on a read image obtained by reading an image formed by the image forming means, when it is determined that the precursor diagnosis process should be executed; an automatic repair means for automatically repairing the image forming means before the sign of the abnormality reaches a predetermined level when the sign of the abnormality is detected by the diagnostic means; An image forming apparatus comprising: (Item 20) 20. The image forming apparatus according to item 19, further comprising the reading means for reading a recording medium on which an image has been formed by the image forming means. (Item 21) 1. A diagnostic device comprising: A setting means for setting the number of sheets; a diagnostic means for executing a precursor diagnosis process for detecting a precursor of an abnormality in the image forming means with respect to a read image obtained by reading an image formed by the image forming means onto a recording medium every time the number of images formed by the image forming means reaches the number set by the setting means; and an automatic repair means for automatically repairing the image forming means when the diagnostic means detects a sign of the abnormality; A diagnostic device comprising:

[0097] <Other embodiments> The present invention 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.The present invention can also be realized by a circuit (e.g., ASIC) that realizes one or more functions.

[0098] The invention is not limited to the above-described embodiments, and various changes and modifications can be made without departing from the spirit and scope of the invention. Accordingly, the following claims are appended to apprise the public of the scope of the invention. [Explanation of symbols]

[0099] 100: Printing system, 101: Image forming device, 102: External controller, 103: Client PC, 104: External LAN, 105: Internal LAN, 106: Video cable, 107: Printing unit, 108: Inserter, 109: Predictive diagnostic unit, 110: Stacker, 111: Finisher

Claims

1. 1. A diagnostic device comprising: a determining means for determining whether or not to execute a symptom diagnosis process for detecting a symptom of an abnormality in the image forming means when the image forming means forms an image on a recording medium; a diagnostic means for not executing the precursor diagnosis process when it is determined that the precursor diagnosis process should not be executed, and for executing the precursor diagnosis process on a read image obtained by reading an image formed by the image forming means using a reading means when it is determined that the precursor diagnosis process should be executed; an automatic repair means for automatically repairing the image forming means before the sign of the abnormality reaches a predetermined level when the sign of the abnormality is detected by the diagnostic means; A diagnostic device comprising:

2. The diagnostic means comprises: an extraction means for extracting a feature quantity for identifying in which part of the image forming means the symptom of the abnormality has occurred, from the detected symptom of the abnormality; an identifying unit that identifies a part of the image forming unit in which a sign of the abnormality occurs based on the extracted feature amount; The diagnostic device according to claim 1, further comprising:

3. 3. The diagnostic device according to claim 2, wherein the feature amount includes size information and shape information of the abnormality precursor, and periodic information of occurrence of the abnormality precursor.

4. The diagnostic means further comprises:

4. The diagnostic device according to claim 3, further comprising a prediction unit that predicts, based on the extracted feature amount, when the detected precursor of the abnormality will reach the predetermined level of abnormality.

5. 5. The diagnostic device according to claim 4, wherein the prediction means predicts the timing at which the detected precursor to the abnormality reaches the predetermined level of abnormality based on the feature amount and the identified parts.

6. 6. The diagnostic device according to claim 5, wherein the prediction means predicts the number of images formed on recording media by the image forming means as the timing when the detected precursor of the abnormality reaches the predetermined level of abnormality.

7. 7. The diagnostic device according to claim 6, wherein the diagnostic means displays the diagnostic result of the precursor on a display unit together with the timing at which the predetermined level of abnormality is reached.

8. The diagnostic device described in any one of claims 1 to 7, characterized in that the judgment means determines to execute the precursor diagnosis process each time the image formation on the recording medium by the image forming means reaches a predetermined number of sheets, or when the precursor diagnosis process currently being executed is completed.

9. 9. The diagnostic device according to claim 8, wherein the predetermined number is set in accordance with a user input.

10. The diagnostic device according to claim 8, characterized in that the determination means makes a determination to advance the timing of executing the precursor diagnosis process when the precursor to the abnormality previously detected is close to the predetermined level.

11. 8. The diagnostic device according to claim 2, wherein the determining means determines whether or not to execute the precursor diagnosis process using different determination conditions for each of the identified parts.

12. 9. The diagnostic device according to claim 8, further comprising a setting unit for setting a level selected from a plurality of levels of image abnormality in response to a user input as the predetermined level of abnormality.

13. The diagnostic device according to claim 12, wherein the levels of the plurality of image abnormalities are classified by at least one parameter of the size and contrast of the abnormality.

14. 9. The diagnostic apparatus according to claim 8, wherein the diagnostic means performs diagnosis using images formed successively on a plurality of recording media as images to be diagnosed.

15. 9. The diagnostic device according to claim 8, wherein the diagnostic means diagnoses an abnormality in an image formed on a recording medium by an image forming means, regardless of the result of determination by the determination means.

16. 9. The diagnostic device according to claim 8, further comprising: a reading unit for reading a recording medium on which an image has been formed by the image forming unit.

17. A method for controlling a diagnostic device, comprising: a determining step of determining whether or not to execute a symptom diagnosis process for detecting a symptom of an abnormality in the image forming means when the image forming means forms an image on a recording medium; a diagnostic step of not executing the precursor diagnosis process when it is determined that the precursor diagnosis process should not be executed, and of executing the precursor diagnosis process on a read image obtained by reading an image formed by the image forming means with a reading means when it is determined that the precursor diagnosis process should be executed; an automatic repair step of automatically repairing the image forming means before the sign of the abnormality reaches a predetermined level when the sign of the abnormality is detected in the diagnosis step; A method for controlling a diagnostic device, comprising:

18. A program for causing a computer to execute each step of a method for controlling a diagnostic device, the control method comprising: a determining step of determining whether or not to execute a symptom diagnosis process for detecting a symptom of an abnormality in the image forming means when the image forming means forms an image on a recording medium; a diagnostic step of not executing the precursor diagnosis process when it is determined that the precursor diagnosis process should not be executed, and of executing the precursor diagnosis process on a read image obtained by reading an image formed by the image forming means with a reading means when it is determined that the precursor diagnosis process should be executed; an automatic repair step of automatically repairing the image forming means before the sign of the abnormality reaches a predetermined level when the sign of the abnormality is detected in the diagnosis step; A program comprising:

19. An image forming apparatus, an image forming means for forming an image on a recording medium; a determining means for determining whether or not to execute a symptom diagnosis process for detecting a symptom of an abnormality in the image forming means when an image is formed on a recording medium by the image forming means; a diagnostic means for not executing the precursor diagnosis process when it is determined that the precursor diagnosis process should not be executed, and for executing the precursor diagnosis process on a read image obtained by reading an image formed by the image forming means using a reading means when it is determined that the precursor diagnosis process should be executed; an automatic repair means for automatically repairing the image forming means before the sign of the abnormality reaches a predetermined level when the sign of the abnormality is detected by the diagnostic means; An image forming apparatus comprising:

20. 20. The image forming apparatus according to claim 19, further comprising: a reading unit that reads a recording medium on which an image has been formed by the image forming unit.

21. 1. A diagnostic device comprising: A setting means for setting the number of sheets; a diagnostic means for executing a precursor diagnosis process for detecting a precursor of an abnormality in the image forming means with respect to a read image obtained by reading an image formed by the image forming means onto a recording medium every time the number of images formed by the image forming means reaches the number set by the setting means; and an automatic repair means for automatically repairing the image forming means when the diagnostic means detects a sign of the abnormality; Equipped with The diagnostic device is characterized in that the diagnostic means advances the timing of executing the precursor diagnosis process when the precursor of the abnormality detected previously is close to a predetermined level.

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