Diagnosis device, control method of the same, program, and image formation 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 apparatus for diagnosing an apparatus from a read image of an image formed by an image forming apparatus, a control method thereof, a program, and an image forming apparatus.

Background Art

[0002] Among the abnormalities of printed images, there are those in which the image quality level deteriorates 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 precursors) and predict the occurrence of "image abnormalities at an image quality level unacceptable to the user" (hereinafter referred to as image defects). As a result, it becomes possible to repair abnormal portions that cause image abnormalities between the image quality levels desired by the user. Patent Document 1 proposes a technique for detecting precursors by outputting a test chart to determine in advance the replacement timing of members and predicting the occurrence of image defects.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] However, the above prior art has the following problems. In a configuration for predicting image abnormalities using a test chart, it is necessary to output a test chart during printing and execute prediction processing. Therefore, there is a risk of reducing the productivity of printing.

[0005] The present invention has been made in view of at least one of the above problems, and provides a mechanism for suitably diagnosing precursors of abnormalities in an image forming apparatus while suppressing the processing load.

Means for Solving the Problems

[0006] The present invention is, for example, a diagnostic apparatus, comprising: determination means for determining whether or not to execute precursor diagnosis processing for detecting a precursor of an abnormality of the image forming means when an image is formed on a recording medium by the image forming means; diagnostic means for executing the precursor diagnosis processing on a read image read by a reading means from the image formed by the image forming means when it is determined that the precursor diagnosis processing is to be executed; and automatic repair means for causing automatic repair of the image forming means before the precursor of the abnormality reaches an abnormality of a predetermined level when the precursor of the abnormality is detected by the diagnostic means.

[0007] Further, the present invention is, for example, an image forming apparatus, comprising: image forming means for forming an image on a recording medium; determination means for determining whether or not to execute precursor diagnosis processing for detecting a precursor of an abnormality of the image forming means when an image is formed on the recording medium by the image forming means; diagnostic means for executing the precursor diagnosis processing on a read image read by a reading means from the image formed by the image forming means when it is determined that the precursor diagnosis processing is to be executed; and automatic repair means for causing automatic repair of the image forming means before the precursor of the abnormality reaches an abnormality of a predetermined level when the precursor of the abnormality is detected by the diagnostic means.

[0008] Further, the present invention is, for example, a diagnostic apparatus, comprising: setting means for setting the number of sheets; diagnostic means for executing precursor diagnosis processing for detecting a precursor of an abnormality of the image forming means on a read image read by a reading means from the image formed by the image forming means every time the number of images formed on the recording medium by the image forming means reaches the number of sheets set by the setting means; and automatic repair means for causing automatic repair of the image forming means when the precursor of the abnormality is detected by the diagnostic means.

Advantages of the Invention

[0009] According to the present invention, it is possible to predict image abnormalities with a suppressed processing load without reducing the productivity of image formation.

Brief Description of the Drawings

[0010]

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Embodiments for Carrying Out 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 invention according to the claims. Although a plurality of features are described in the embodiments, not all of these plurality of features are essential to the invention, and the plurality of features may be arbitrarily combined. Further, in the accompanying drawings, the same or similar configurations are denoted by the same reference numerals, and redundant descriptions are omitted.

[0012] <First Embodiment> <System Configuration> Hereinafter, a first embodiment of the present invention will be described. Referring to FIG. 1, a network configuration example including a printing system (image processing system) according to the present embodiment will be described. 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 communicably connected to each other via an internal LAN 105 and a video cable 106. The external controller 102 is communicably connected to a client PC 103 via an external LAN 104. In the present embodiment, a form in which the image forming apparatus 101 and the external controller 102 are provided separately will be described as an example, but there is no intention of limiting the present invention. For example, the external controller 102 may be provided integrally with the image forming apparatus 101. In that case, the image forming apparatus 101 and the client PC 103 are communicably connected.

[0013] The client PC 103 can issue a printing instruction to the external controller 102 via the external LAN 104. A printer driver having a function of converting image data to be printed into a page description language (PDL) processable by the external controller 102 is installed on the client PC 103. A user who wants to perform printing can issue a printing instruction from various applications installed on the client PC 103 via the printer driver by operating the client PC 103. Based on the printing instruction from the user, the printer driver transmits PDL data, which is printing data, to the external controller 102. The PDL data is printing data specified by the user, data generated within the client PC 103, or selected data. When the external controller 102 receives the PDL data from the client PC 103, it analyzes and interprets the received PDL data. Based on the result of the interpretation, it performs rasterization processing to generate a bitmap image (printing image data) with a resolution suitable for the image forming apparatus 101, and issues a printing instruction by submitting a printing job to the image forming apparatus 101.

[0014] Subsequently, the image forming apparatus 101 will be described. In the image forming apparatus 101, devices having a plurality of different functions are connected, and it is configured to enable complex printing processes such as binding. The image forming apparatus 101 includes a printing unit 107 (image forming unit), an inserter 108, a pre-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 content of the print job and discharges the printed recording medium (such as paper or sheet). The printed recording medium discharged from the printing unit 107 is conveyed through the interiors of the respective devices in the order of the pre-symptomatic diagnosis unit 109, the stacker 110, and the finisher 111. In the present embodiment, the image forming apparatus 101 of the printing system 100 is an example of an image forming apparatus. However, the printing unit 107 included in the image forming apparatus 101 may also be referred to as an image forming apparatus. The printing unit 107 forms (prints) an image on the recording medium fed and conveyed from a paper feeding unit disposed 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, a partition recording medium for partitioning at an arbitrary position with respect to a series of recording medium groups conveyed from the printing unit 107. The pre-symptomatic diagnosis unit 109 detects "image abnormalities at an image quality level acceptable to the user" (hereinafter referred to as pre-symptoms) with respect to the image forming apparatus 101 based on the printed recording medium on which an image is printed by the printing unit 107 and conveyed through the conveyance path, and predicts "image abnormalities at an image quality level unacceptable to the user" (hereinafter referred to as image defects). Specifically, the pre-symptomatic diagnosis unit 109 reads the image printed on the conveyed printed recording medium and performs a diagnosis from the obtained read image. The diagnosis of pre-symptoms detects pre-symptoms from the difference in read signal values in the read image, and predicts image defects based on the information of the detected pre-symptoms. Details of the processing of the pre-symptomatic diagnosis unit will be described later. Note that the use of the pre-symptomatic diagnosis unit is not limited to the above example. It may also be provided with an inspection system for inspecting the presence or absence of printing abnormalities of the printed recording medium and a diagnosis system for diagnosing abnormalities of the image forming apparatus 101 from 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 medium. The recording medium after the processing by the finisher 111 is discharged to a predetermined paper discharge tray.

[0018] In the configuration example of FIG. 1, an external controller 102 is connected to the image forming apparatus 101. However, the present embodiment is also applicable to a configuration different from this. 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 transmitted from the client PC 103 to the image forming apparatus 101 without going through the external controller 102. In this case, data analysis and rasterization for the print data are executed by the image forming apparatus 101.

[0019] <Hardware Configuration of Image Forming Apparatus 101> With reference to FIG. 2, a hardware configuration example of the image forming apparatus 101 according to the present embodiment will be described. Hereinafter, a specific operation example of the image forming apparatus 101 will be described with reference to FIG. 2. In the printing unit 107, various recording media (papers) are stored in the paper feed deck. At the time of image formation, among the recording media stored in each paper feed deck, the uppermost recording medium is separated one by one and fed to the conveyance path 303.

[0020] Further, the image forming stations 304 to 307 each include a photosensitive drum (photoconductor), and toner images are formed on the photosensitive drums using toners of different colors. Specifically, the image forming stations 304 to 307 form toner images using yellow (Y), magenta (M), cyan (C), and black (K) toners, respectively.

[0021] The toner images of each color formed in the image forming stations 304 to 307 are sequentially superimposed and transferred (primary transfer) onto the intermediate transfer belt 308. The toner image transferred onto the intermediate transfer belt 308 is conveyed to the 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 the recording medium conveyed through the conveyance path 303 (secondary transfer). The recording medium after secondary transfer is conveyed to the fixing unit 311. The fixing unit 311 includes a pressure roller and a heating roller. While the recording medium passes between these rollers, heat and pressure are applied to the recording medium, and a fixing process for fixing the toner image to the recording medium is performed. The recording medium that has passed through the fixing unit 311 is conveyed through the conveyance path 312 to the connection point 315 between the printing unit 107 and the preliminary diagnosis unit 109. In this way, a color image is formed (printed) on the recording medium.

[0022] When further fixing processing is required according to the type of the recording medium, the recording medium that has passed through the fixing unit 311 is guided to the conveyance path 314 where the fixing unit 313 is provided. The fixing unit 313 performs further fixing processing on the recording medium conveyed through the conveyance path 314. The recording medium that has passed through the fixing unit 313 is conveyed to the connection point 315. Also, when the operation mode for double-sided printing is set, an image is printed on the first side, and the recording medium conveyed through the conveyance path 312 or the conveyance path 314 is guided to the reverse path 316. The recording medium reversed in the reverse path 316 is guided to the double-sided conveyance path 317 and conveyed to the secondary transfer position 309. As a result, the toner image is transferred to the second side opposite to the first side of the recording medium at the secondary transfer position 309. Thereafter, by passing the recording medium through the fixing unit 311 (and the fixing unit 313), the formation of the color image on the second side of the recording medium is completed.

[0023] When the formation (printing) of the image in the printing unit 107 is completed, the printed recording medium conveyed to the connection point 315 is conveyed into the pre-symptomatic diagnosis unit 109. The pre-symptomatic diagnosis unit 109 includes image reading units 331 and 332 having CIS (Contact Image Sensor) on the conveyance path 330 through which the printed recording medium from the printing unit 107 is conveyed. The image reading units 331 and 332 are arranged at positions facing each other via the conveyance path 330. The image reading units 331 and 332 are each configured to read the upper surface (first surface) and the lower surface (second surface) of the recording medium. Note that the image reading unit may be configured by, for example, a CCD (Charge Coupled Device) or a line scan camera instead of the CIS.

[0024] The pre-symptomatic diagnosis unit 109 is implemented based on an instruction to execute the pre-symptomatic diagnosis process. Specifically, the instruction to execute the pre-symptomatic diagnosis may be any method that can determine whether to execute the pre-symptomatic image diagnosis, such as a method of associating in advance whether to execute the pre-symptomatic diagnosis process with the print job, or a method of pressing the pre-symptomatic image diagnosis execution button at the start of the job. Also, an automatic setting method such as automatically setting to execute the pre-symptomatic image diagnosis simultaneously with startup may be used. When the execution of the pre-symptomatic diagnosis process is instructed, the pre-symptomatic diagnosis unit 109 determines whether the image printed on the printed recording medium conveyed on the conveyance path 330 is to be used for the pre-symptomatic diagnosis. Then, using the read image of the recording medium determined to be the object of the pre-symptomatic diagnosis, an image pre-symptomatic diagnosis process for determining the presence or absence of pre-symptomatic occurrence in the image forming apparatus 101 is executed. The recording medium determined not to be the object of the pre-symptomatic diagnosis is not used as the target image for the image pre-symptomatic diagnosis process. Specifically, the pre-symptomatic diagnosis unit 109 uses the image reading units 331 and 332 to execute a reading process for reading the image of the printed recording medium at the timing when the recording medium determined to be the object of the pre-symptomatic diagnosis among the printed recording media being conveyed reaches a predetermined position. The recording media that are not the objects of diagnosis may or may not be subjected to the reading process in the same manner as the recording media that are the objects of diagnosis. The recording medium that has passed through the pre-symptomatic diagnosis unit 109 is sequentially conveyed to the stacker 110.

[0025] The stacker 110 includes a stack tray 341 as a tray on which the printed recording media conveyed from the pre-diagnosis unit 109 arranged upstream in the conveyance direction of the printed recording media is stacked. The printed recording media that has passed through the pre-diagnosis unit 109 is conveyed through the conveyance path 344 in the stacker 110. When the printed recording media conveyed through the conveyance path 344 is guided to the conveyance path 345, the printed recording media is stacked on the stack tray 341. The printed recording media that has been conveyed without being stacked and discharged in the stacker 110 is conveyed to the subsequent finisher 111 through the conveyance path 348.

[0026] The stacker 110 further includes an inversion unit 349 for inverting the orientation of the conveyed printed recording media. The inversion unit 349 is used, for example, to make the orientation of the recording media input to the stacker 110 the same as the orientation of the printed recording media when it is stacked on the stack tray 341 and output from the stacker 110. Note that the inversion operation by the inversion unit 349 is not performed on the printed recording media that is conveyed to the finisher 111 without being stacked in the stacker 110.

[0027] The finisher 111 executes the finishing function designated by the user on the printed recording medium conveyed from the pre-diagnosis unit 109 disposed upstream in the conveyance direction of the printed recording medium. In the present embodiment, the finisher 111 has finishing functions such as a staple function (stapling at one or two locations), a punching function (two or three holes), and a center-stitching binding function. The finisher 111 includes two paper discharge trays 351 and 352. When the finishing process by the finisher 111 is not performed, the printed recording medium conveyed to the finisher 111 is discharged to the paper discharge tray 351 through the conveyance path 353. When the finishing process such as staple processing is performed by the finisher 111, the printed recording medium conveyed to the finisher 111 is guided to the conveyance path 354. The finisher 111 executes the finishing process designated by the user on the printed recording medium conveyed through the conveyance path 354 using the finishing process unit 355, and discharges the printed recording medium on which the finishing process has been executed to the paper discharge tray 352.

[0028] <Functional Configuration> Referring to FIG. 3, the functional configurations of the image forming apparatus 101, the external controller 102, and the client PC 103 according to the present embodiment will be described. 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 transmit and receive data to and from each other.

[0029] The communication I / F 201 is connected to the pre-diagnosis unit 109, the stacker 110, and the finisher 111 via the communication cable 260. The CPU 206 performs communication for controlling each device via the communication I / F 201. The network I / F 204 is connected to the external controller 102 via the internal LAN 105 and is used for communication of control data and the like. The video I / F 205 is connected to the external controller 102 via the video cable 106 and is used for communication of 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. Various programs or data are stored in the HDD unit 208. The CPU 206 controls the operation of the entire printing unit 107 by executing the programs stored in the HDD unit 208. Also, the number of printed sheets, which counts the total number of printed sheets, is stored in the HDD unit 208 and is used for determining whether to execute automatic repair. Programs and data necessary for the CPU 206 to perform various processes are stored in the memory 207. The memory 207 operates as a work area for the CPU 206. The UI display unit 225 receives inputs of various settings and operation instructions from the user and is used for displaying various information such as setting information and the processing status of print jobs. For example, it receives various instructions from the user such as an execution instruction and setting of pre-diagnosis, and setting of paper information.

[0030] The pre-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 to be able to transmit and receive data to and from each other via a system bus 219. 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 pre-symptom diagnosis unit 109 via the communication I / F 211. The CPU 214 controls the operation of the pre-symptom diagnosis unit 109 by executing a control program stored in the memory 215. A control program for the pre-symptom diagnosis unit 109 is stored in the memory 215. The image reading units 331 and 332 read the image of the conveyed recording medium according to the instruction of the CPU 214. The CPU 214 diagnoses the presence or absence of pre-symptoms of the image forming apparatus 101 based on the read images for pre-symptom diagnosis read by the image reading units 331 and 332.

[0031] The UI display unit 241 is used for displaying pre-symptom diagnosis results, setting screens, etc. The operation unit is also used as the UI display unit 241 and is operated by the user to receive various instructions from the user, such as changing the settings of the pre-symptom diagnosis unit 109 and giving an execution instruction for image pre-symptom diagnosis. Various setting information and image data necessary for image pre-symptom diagnosis are stored in the HDD unit 216. The various setting information and image data stored in the HDD unit 216 can be reused.

[0032] The stacker 110 controls whether to discharge the printed recording medium conveyed on the conveyance path to the stack tray, to the escape tray, or to convey it to the finisher 111 connected to the downstream side 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 binding.

[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, 257, and a video I / F 258. These devices are connected to each other via a system bus 259 so as to be able to transmit and receive data. The CPU 251 controls the operations of the entire external controller 102, such as receiving print data from the client PC 103, performing RIP processing, and transmitting the print data to the image forming apparatus 101, by executing programs stored in the HDD unit 253. Programs and data required when the CPU 251 performs various processes are stored in the memory 252. The memory 252 operates as a work area for the CPU 251.

[0034] Various programs and data are stored in the HDD unit 253. The keyboard 256 is used to input operation instructions for the external controller 102 from the user. The display unit 254 is, for example, a display and is used to display information on the running applications in the external controller 102 and operation screens. The network I / F 255 is connected to the client PC 103 via the external LAN 104 and is used for communication of 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 communication of data such as print instructions. The external controller 102 is configured to be communicable with the printing unit 107, the pre-diagnosis unit 109, the stacker 110, and the finisher 111 via the internal LAN 105 and the communication cable 260. The video I / F 258 is connected to the printing unit 107 via the video cable 106 and is used for communication of 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 to be able to transmit and receive data to and from each other via a system bus 269. The CPU 261 controls the operations of each device via the system bus 269 by executing a program stored in the HDD unit 263. Thereby, various processes by the client PC 103 are realized. For example, the CPU 261 generates print data and issues a print instruction by executing a document processing program stored in the HDD unit 263. The memory 262 stores programs and data required when the CPU 261 performs various processes. The memory 262 operates as a work area for the CPU 261.

[0036] In the HDD unit 263, various applications such as a document processing program, programs such as a printer driver, and various data are stored. The display unit 264 is, for example, a display and is used for displaying information on running applications in the client PC 103 and operation screens. The keyboard 265 is used for inputting 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] <Precursor diagnosis process> Referring to FIG. 4, the processing procedures of the printing operation and the pre-symptomatic diagnosis process according to the present embodiment will be described. Note that FIG. 4 shows the overall flow from the work before the start of the pre-symptomatic diagnosis to the execution of the pre-symptomatic diagnosis and the automatic repair. In the description of the flowchart, the symbol "S" represents a step. This also applies to the following description of the flowchart. The processes described below are executed by the CPU 206 of the printing unit 107, the CPU 214 of the pre-symptomatic diagnosis unit 109, and the CPU 251 of the external controller 102. Here, the description will be given in a form where various CPUs cooperate to execute the processes described below, but a form in which an integrated single CPU provided in the image forming apparatus executes all the processes may also be possible.

[0038] In S401, the CPU 214 of the pre-symptomatic diagnosis unit 109 receives an instruction for pre-symptomatic diagnosis from the user or the service technician via the UI display unit 241 that also serves as the operation unit, and checks the settings of the pre-symptomatic diagnosis process. In the present embodiment, a screen for receiving an instruction to start the pre-symptomatic diagnosis is displayed on the UI display unit 241. When the start instruction is received, a setting for image abnormality (image defect) at a predetermined level is made as the setting of the pre-symptomatic diagnosis. Note that the start instruction is not limited to the above example, and it is sufficient if the execution of the pre-symptomatic diagnosis is understood. For example, a job and the execution of the pre-symptomatic diagnosis may be associated in advance, and when a job for executing the pre-symptomatic diagnosis is received, it may be determined that the start of the pre-symptomatic diagnosis is instructed. Here, the description will be given in a form where the instruction is received via the UI display unit 241 of the pre-symptomatic diagnosis unit 109, but the present invention is not intended to be limited, and an instruction may be received from the client PC 103 via the external controller 102.

[0039] In this embodiment, the preliminary diagnosis setting classifies the predetermined level for determining image defects into nine levels based on the size and contrast of image abnormalities. Here, the case of selecting the level for determining image defects according to user input will be described. FIG. 5 shows an example of the image abnormality level. The image abnormality level 501 selected by the user as the criterion (predetermined level) for image defects is set such that the larger the size 502 of the image abnormality and the higher the contrast 503, the lower the level. On the other hand, the smaller the size 502 of the image abnormality and the lower the contrast 503, the higher the level. Note that there is no intention to limit the setting of the image abnormality level to the above levels, and it can be arbitrarily set according to the performance of the image forming apparatus and the like. Also, any level for determining image defects may be used, and it may be selected and set from parameters such as only size or only contrast. Further, a method of setting a numerical value instead of a level may be used. When the confirmation of the preliminary diagnosis setting is completed, the process proceeds to the print process of the print job. Thus, according to this embodiment, a plurality of image abnormality levels are classified by at least one parameter of the size and contrast of the abnormality.

[0040] In S402, the CPU 206 of the printing unit 107 receives a print instruction from the client PC 103 or the external controller 102 and starts the printing operation. Specifically, the CPU 251 of the external controller 102 performs PDL interpretation such as font type, size, and designated position on the paper from the description in the PDF file according to the PDF print job received in S401. Next, the CPU 251 creates RIP data rasterized into a bitmap according to the resolution setting as interpreted by the PDL interpretation in S402. The CPU 251 associates the items extractable from the RIP data. Details of the items extractable from the features will be described later.

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

[0042] In S403, the CPU 214 of the pre-symptomatic diagnosis unit 109 determines whether the printed recording medium is the object of pre-symptomatic diagnosis. Since the pre-symptom is that the print quality gradually deteriorates as the number of printed sheets progresses and finally changes to image defects, it is not necessary to perform pre-symptomatic diagnosis for each page. Therefore, the CPU 214 determines whether the printed recording medium is a recording medium for pre-symptomatic diagnosis or a recording medium not for pre-symptomatic diagnosis based on the determination conditions. Details of the determination conditions for the pre-symptomatic diagnosis object will be described later. If the printed recording medium is determined to be a non-pre-symptomatic diagnosis target image (No case), the process proceeds to S402. On the other hand, if the printed recording medium is determined to be a recording medium for pre-symptomatic diagnosis (Yes case), the process proceeds to S404.

[0043] In S404, the CPU 214 executes the pre-symptom diagnosis described later and stores the execution result in the HDD unit 216. In S405, the CPU 214 determines whether to execute automatic repair. In this embodiment, the automatic repair execution timing is set to a predetermined number of sheets predicted by the pre-symptomatic diagnosis. The number of printed sheets stored in the HDD unit 208 is read out, and when the number of printed sheets reaches the predetermined number, automatic repair is executed. Details of the automatic repair to be executed and details of the number of sheets set as the automatic repair execution timing will be described later. If it is not the automatic repair execution number of sheets (No case), the process proceeds to S406. If it is the automatic repair execution number of sheets (Yes case), the process proceeds to S406 and automatic repair is executed.

[0044] In S406, the CPU 214 causes the printing unit 107 to execute automatic repair according to the preliminary diagnosis result stored in the HDD unit 216. After the automatic repair is executed, the process proceeds to S406. In S407, the CPU 206 of the printing unit 107 determines whether the job has ended. If the job continues (No in S406), the process proceeds to S402. If the job has ended (Yes in S405), the processing of this flowchart ends.

[0045] <Feature extractable items> With reference to FIGS. 6 and 7, the feature extractable items according to this embodiment will be described. FIG. 6 shows the state of feature extraction according to this embodiment. FIG. 7 shows an example of a feature extraction possible map for each feature extractable item. In this embodiment, the feature extractable items are set to a total of 8 items, which are a combination of 4 types of colors, cyan, magenta, yellow, and black, and 2 types, whether an abnormality occurs in the dark direction (contrast plus direction) or an abnormality in the light direction (contrast minus direction). 700 shows feature extraction possible maps (701 to 708) represented by a map in which for each item of the feature extractable items, a feature extractable pixel is set to 1 and a non-feature extractable pixel is set to 0.

[0046] For example, it is assumed that an image abnormality has occurred in an image 605 printed with RIP data 601 including a dark region 602 of the density of black for monochrome (for black and white printing), a light region 603 of the density of black, and a white background region 604. When a vertical streak 612 in the contrast minus direction occurs at the main scanning position X1, the image abnormality appears in the dark portion 606 of the black density, but does not appear in the white portion 608 or the light portion 607 of the black density. That is, for the feature of the black contrast minus direction, a place where the black density is equal to or higher than a certain density is feature extractable. Therefore, in the map 708 of the feature extractable item in the black contrast minus direction, 1 that can be diagnosed is set for pixels where the black density exceeds 40% (615), and the other pixels are stored as 0 as non-feature extractable places (616, 617).

[0047] Also, when the vertical streak 613 with a plus-direction contrast of black occurs at the position of the main scanning position X2, the vertical streak becomes apparent in the white background portion 611 and the portion 610 with a low black density, but does not become apparent in the portion 609 with a high black density. That is, for the feature of the plus direction of the black contrast, feature extraction is possible in the portion where the black density is below a certain density. Therefore, the map 707 of the feature extractable items in the plus direction of the black contrast sets 1 that can be diagnosed for the pixels with a black density of 60% or less (620, 621), and stores 0 as an undiagnosable area for the 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 feature extractable maps 702, 704, and 706 are stored with the minus directions of the cyan, magenta, and yellow contrasts being non-feature extractable items. Also, since the feature extraction of plus-direction cyan, magenta, and yellow is possible only in the white background area 604 without black, the feature extractable maps 701, 703, and 705 are stored.

[0049] Note that the setting of the 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 may be used as long as the area where feature extraction is possible for the feature extraction items can be known. For example, instead of determining for each pixel, the RIP data may be divided into a plurality of blocks, and whether or not the block is diagnosable may be set.

[0050] <S404: Precursor Diagnosis Execution Process> Referring to FIG. 8, the details of the S404 precursor diagnosis process according to this embodiment will be described. FIG. 8 is a flowchart showing the procedure of the image precursor diagnosis process executed by the precursor diagnosis unit 109. The processes described below are executed by the CPU 214 of the precursor diagnosis unit 109. Note that they may also 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 those CPUs.

[0051] In S801, the CPU 214 executes a process of reading a recording medium to be precursor-diagnosed by the image reading units 331 and 332. The read image of the recording medium to be determined is stored in the HDD unit 216 of the precursor diagnosis unit 109 as the target image for precursor diagnosis. When the target image for precursor diagnosis is stored, the process proceeds to S802. In S802, the CPU 214 compares the reference image with the target image for precursor diagnosis in order to determine the precursor of an abnormality in the printing unit 107 and detects the precursor. In this embodiment, the reference image and the target image for precursor diagnosis are compared to obtain a difference value. Further, the precursor diagnosis unit 109 includes a correction unit that corrects the non-linearity between the signal value and the luminance of the target image for precursor diagnosis acquired by the image reading unit 331, and may correct the signal value of the precursor diagnosis image and then acquire the difference image data.

[0052] When the difference value acquired by the precursor diagnosis unit 109 exceeds the threshold value, the precursor diagnosis unit 109 sets 1 in the difference image data as indicating the presence of a difference. On the other hand, when the difference value is below the threshold value, 0 is set in the difference image data. In this embodiment, the threshold value is set to a value smaller in size and lower in contrast than the level set in S401. For example, when 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 value. The precursor diagnosis unit 109 stores 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, at S803, the CPU 214 determines whether a precursor has occurred. The determination is made based on whether there is data containing 1 in the differential image data. If the determination result is that no precursor has occurred (No in S803), the CPU 214 ends the processing of this flowchart. On the other hand, if the determination result is that a precursor has occurred (the differential image data contains 1) (Yes in S803), the CPU 214 advances the processing to S804.

[0054] At S804, the CPU 214 extracts feature quantities for identifying parts where precursors of abnormalities in the printing unit 107 have occurred from the target image data for precursor diagnosis, the differential image data, and the diagnosable items associated with the reference image. The CPU 214 performs differential feature extraction from the target image for precursor diagnosis corresponding to the differential region determined to have "difference" from the differential image data obtained at S802 and the diagnosable items. In this feature extraction process, for example, colorant information and contrast information are obtained from the differential image according to the diagnosable items. The colorant information is information indicating which color of yellow, magenta, cyan, or black the precursor has occurred in. The contrast information is information representing whether the contrast of the precursor is in the contrast plus direction or the contrast minus direction with positive and negative numerical values. Here, the CPU 214 does not extract as features colors or the contrast plus and contrast minus directions that are not set in the diagnosable items determined from the RIP data.

[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 of the precursor such as the dot shape, vertical stripe shape, and horizontal stripe shape. In this embodiment, an example of determining the acquisition of the shape information from the aspect ratio of the width and height of the acquired size information will be described. Specifically, when the aspect ratio obtained by width ÷ height exceeds a predetermined threshold, the shape is determined to be a horizontal stripe. When the aspect ratio is below the threshold, the shape is determined to be a vertical stripe, and those that do not fit either are determined to be dots. Note that the acquisition of the shape information is not limited to the above example, and any method that can identify the shape of the precursor such as dots, horizontal stripes, or vertical stripes may be used. For example, those with a width equal to or greater than the threshold may be determined to be horizontal stripes, those with a height equal to or greater than the threshold may be determined to be vertical stripes, and the rest may be determined to be dots. Also, coordinate information indicating the position in a direction perpendicular to the conveyance direction of the recording medium in the printing unit 107, and periodic information indicating that precursors with similar characteristics occur periodically in the conveyance direction of the recording medium in the printing unit 107 can also be cited as features.

[0056] In S805, based on the feature information of the difference region obtained in S804, the CPU 214 identifies the parts in the printing unit 107 and the image reading unit 331 that are the cause of the precursor. Among the difference regions, a combination with the same color and a high similarity is selected, and it is possible to identify which part the precursor has occurred in from the periodic information of the selected combination. In this embodiment, a case where the determination of the combination with a high similarity is obtained by a known template matching technique will be described.

[0057] Compare the images of the precursors using template matching, and set the highest value as the similarity between the precursors. Determine that precursors with a similarity higher than a predetermined threshold are a combination with a high similarity. Note that the similarity determination method is not limited to the above, and any method that can determine whether precursors are similar may be used. For example, a method of determining the similarity between images using machine learning or a method of obtaining the similarity by comparing the feature amounts and feature points of precursor images may be applied. The CPU 214 reads the current number of printed sheets stored in the HDD unit 208, associates the extracted features with the occurring parts, stores them in the HDD unit 216, and proceeds to S806.

[0058] In S806, the CPU 214 predicts the number of printed sheets at which an image defect will occur based on the parts that are the factors identified in S805, the size and contrast of the precursors, the feature information of past precursors stored in the HDD unit 216, and the deterioration degree table for each part. Details of the prediction method will be described later. The CPU 214 stores the predicted number of printed sheets in the HDD unit 216 and proceeds to S807.

[0059] In S807, the CPU 214 determines whether it is automatically repairable. Cases where automatic repair is impossible include responses that require user operations such as cleaning the dirt on the reading glass surfaces of the image reading units 331 and 332 of the precursor diagnosis unit 109, adjusting the recording medium to be used, and responses that require the work of a service technician such as replacing parts. Also included in cases where automatic repair is impossible are responses to reading abnormalities in the image reading unit and fibers and foreign substances that are present in the recording medium before image formation. If automatic repair is impossible, the process proceeds to S808.

[0060] On the other hand, items that can be automatically repaired are considered to be automatically recoverable responses in the printing unit 107 such as cleaning the wires of the corona charger of the photoreceptor drum provided in the image forming stations 304 to 307 of the printing unit 107 by a charger cleaning mechanism (not shown) and cleaning the grid. If automatic repair is possible, the process proceeds to S809.

[0061] In S808, since the CPU 214 cannot perform automatic repair and thus needs to take countermeasures, it displays this on the UI display unit 241 of the pre-diagnosis unit 109 and ends the processing of this flowchart. FIG. 9 shows an image of the display of the diagnosis result when countermeasures are necessary. In the result display, the number of prints at which an image defect is predicted to occur is subtracted from the current number of prints saved in the HDD unit 216, and it is displayed as shown in 901 how many more prints an image defect will occur. Also, based on the diagnosis result, necessary countermeasures 902 such as "cleaning the reading glass surface" and "notifying the service technician" are displayed together. Note that the notification of countermeasures is not limited to the above, and any method that can confirm the result is acceptable. 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. Also, the notification content may display the presence or absence of precursor detection and the detailed content side by side, or may display them in chronological order or display images side by side.

[0062] On the other hand, in S809, the CPU 214 saves the content of automatic repair in the HDD unit 216 associated with the number of prints until the image defect saved in the HDD unit 216, and ends the processing of this flowchart. For example, when a precursor has occurred in the corona charger of the photoreceptor drum, cleaning the wire of the corona charger is saved as the content of automatic repair.

[0063] <Setting of determination conditions for pre-diagnosis target> The determination conditions for the pre-symptomatic diagnosis target for the printed recording medium in S403 of FIG. 4 will be described. Since the pre-symptom is that the print quality gradually deteriorates into image defects as the number of printed sheets progresses, it is not necessary to perform pre-symptomatic diagnosis for each page. Therefore, in this embodiment, the timing for performing pre-symptomatic diagnosis is determined. For example, when the pre-symptomatic diagnosis count number stored in the HDD unit 216 reaches a pre-defined number of printed sheets such as every 200 sheets, the image is determined to be a pre-symptomatic diagnosis target. When it is determined that it is not a pre-symptomatic diagnosis target (in the case of No in S403), the pre-symptomatic diagnosis count number is incremented by 1 and stored in the HDD unit 216, so that the count increases up to the number of sheets that are the pre-symptomatic diagnosis target conditions. When the number of sheets for pre-symptomatic diagnosis target determination is equal to the pre-symptomatic diagnosis count number, the pre-symptomatic diagnosis process S404 is executed, and when the process ends, the pre-symptomatic diagnosis count number is reset (set to 0) and stored in the HDD unit 216. Note that the number of sheets for the determination conditions of the pre-symptomatic diagnosis target is not limited to a pre-defined number, and may be a number set by the user. Furthermore, the determination conditions for the pre-symptomatic diagnosis target are not intended to be limited to the number of printed sheets, and may be any determination conditions that can track the pre-symptom without degrading productivity. For example, when the diagnosis result in the pre-symptomatic diagnosis is obtained, the next pre-symptomatic diagnosis may be started. This is effective when the execution time of the pre-symptomatic diagnosis process is longer than the printing time for one recording medium.

[0064] <Number of predicted image defects> With reference to FIGS. 10 and 11, the prediction of the number of printed sheets reaching image defects in S806 will be described. In this embodiment, the pre-symptomatic diagnosis unit 109 predicts the number of printed sheets that will result in image defects based on the size and contrast information of the pre-symptoms for the same parts stored in the HDD unit 216 during past pre-symptomatic diagnoses. Here, a method for predicting the number of occurrences of image defects from the transition of the size and contrast of the occurring pre-symptoms will be described. 1001 has the vertical axis indicating the size of the pre-symptom and the horizontal axis indicating the number of printed sheets. 1012 has the vertical axis indicating the contrast of the pre-symptom and the horizontal axis indicating the number of printed sheets.

[0065] For example, as shown in FIG. 10, assume that the current precursor diagnosis result is 300 printed sheets, and the precursor B of the black drum has occurred, with a size of 275 μm and a contrast of 20%. If information on precursor A with a size of 270 μm and a contrast of 19% in the black drum was stored at 100 printed sheets during past precursor diagnosis, then at 200 printed sheets, the size has deteriorated by 5 μm and the contrast has deteriorated by 1%. In this way, the predicted number of defective images in the case of deterioration proportional to the number of printed sheets will be described.

[0066] When the image abnormality level set in S401 is level 7 (506), a size of 400 μm and a contrast of 30% serve as the criteria for determining a defective image. Therefore, from the perspective of size, based on 1001, it can be predicted that it will deteriorate into defective image C in the next 5000 sheets, and from the perspective of contrast, based on 1012, it can be predicted that it will deteriorate into defective image D in the next 2000 sheets. When determining the predicted number of sheets until either the size or the contrast reaches the defective image level (level 7), the contrast is determined to be a defective image in the next 2000 sheets, and the predicted number of printed sheets is less than the next 5000 sheets from the perspective of size. Thus, the predicted result until the defective image is determined to be the next 2000 sheets. Therefore, since the current number of printed sheets is 300, it can be predicted that there is a possibility of deteriorating to the image abnormality level of a defective image at 2300 printed sheets, which is 2000 sheets later. The CPU 214 stores the result of predicting the number of printed sheets at which a defective image occurs in S806 in the HDD unit 216 and proceeds to S807.

[0067] Also, a method may be used in which the number of sheets and the deterioration rate of how much each part deteriorates with respect to size and contrast are retained in advance and obtained by referring to them. The case where a deterioration prediction table for each part is retained in advance will be described. FIG. 11 shows an example of a deterioration prediction table 1100. In the deterioration prediction table 1100, information on how much the size 1102 and the contrast 1103 deteriorate per 100 sheets for the part 1101 is stored.

[0068] For example, a precursor with a black drum, a size of 275 μm, and a contrast of 20% has occurred, and the case where level 7 (506) is set as the image defect level will be described. In this case, when the size and contrast of the image defect level deteriorate to 400 μm and 30% respectively, the size deteriorates by 400 μm - 275 μm = 125 μm, and the contrast deteriorates by 30% - 20% = 10%. The photoreceptor drum deteriorates by 2.5 μm in size and 0.5% in contrast per 100 sheets. Therefore, from the perspective of size, the number of sheets until the timing of image defect is 125 μm ÷ 2.5 μm × 100 sheets = 5000 sheets, and from the perspective of contrast, it is 10% ÷ 0.5% × 100 sheets = 2000 sheets. When determining the predicted number of sheets at which either the size or the contrast reaches the image defect level, as in FIG. 10, it can be determined that the image defect level will be reached after 2000 sheets. That is, if the current number of printed sheets is 300, it can be predicted that the image defect level will be reached at the 2300th printed sheet, which is 2000 sheets later. Note that the prediction method only needs to be able to predict how many sheets later the image defect level will be reached from the detected precursor. It may be predicted not only from the past once but also from the trends of multiple past times. Also, a method of predicting how many sheets later an image defect will occur by machine learning using the precursor image and feature amount and the image abnormality level as inputs may be used.

[0069] As described above, when an image is formed on a recording medium by the image forming unit (printing unit), the diagnostic apparatus according to the present embodiment determines whether to execute a precursor diagnosis process for detecting a precursor of an abnormality of the image forming apparatus. Further, when it is determined that the precursor diagnosis process is to be executed, the diagnostic apparatus executes the precursor diagnosis process on the read image read by the reading unit from the image formed by the image forming unit. When a precursor of an abnormality is detected, the automatic repair of the image forming unit is performed before the precursor of the abnormality reaches an abnormality of a predetermined level. Thus, according to the present embodiment, it is possible to perform a precursor diagnosis that suppresses the processing load without reducing productivity by determining whether the image is a target image for precursor diagnosis and performing the precursor diagnosis on the printed recording medium. That is, according to the present embodiment, a mechanism is provided that preferably diagnoses a precursor of an abnormality of the image forming apparatus while suppressing the processing load. <Modification Example 1> The present invention is not limited to the above-described embodiments and can be variously modified. Hereinafter, Modification Example 1 of the first embodiment will be described. In the first embodiment, with respect to a printed recording medium, it is determined whether it is a recording medium to be pre-symptom diagnosed in the pre-symptom diagnosis execution determination (S403), and an example is described in which the recording medium to be pre-symptom diagnosed is read in S802 within the pre-symptom diagnosis execution (S404). However, a configuration may be adopted in which after reading the printed recording medium, it is determined whether the read image is an image to be pre-symptom diagnosed.

[0070] <Pre-symptom diagnosis process> With reference to FIGS. 12 and 13, the processing procedure of the pre-symptom diagnosis process in this modification example will be described. In this Modification Example 1, it is determined whether the read image is an image to be pre-symptom diagnosed, and the pre-symptom diagnosis is executed. The same steps are assigned to the same processes as the flowchart of FIG. 4, and the description thereof is omitted. The processes described below are executed by the CPU 206 of the printing unit 107, the CPU 214 of the pre-symptom diagnosis unit 109, and the CPU 251 of the external controller 102. Here, a form will be described in which various CPUs cooperate to execute the processes described below, but a form may also be adopted in which an integrated single CPU provided in the image forming apparatus executes all the processes.

[0071] When printing is executed in S402, in S1201, the CPU 214 of the pre-symptom diagnosis unit 109 executes a process of reading the printed recording medium. The read image is stored in the HDD unit 216 of the pre-symptom diagnosis unit 109. When the read image is stored, the process proceeds to S1202. In S1202, the CPU 214 determines whether the read image is to be the object of pre-symptom diagnosis. Specifically, the CPU 214 determines whether the read image is an image to be pre-symptom diagnosed based on the determination conditions for the pre-symptom diagnosis target. If it is a pre-symptom diagnosis target (Yes in S1202), the process proceeds to S1203, and if it is not a pre-symptom diagnosis target (No in S1202), the process proceeds to S405.

[0072] Referring to FIG. 13, the detailed processing procedure of the precursor diagnosis execution process (S1203) will be described. The processes described below are executed by, for example, the CPU 214 of the precursor diagnosis unit 109. Note that they may also 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 those CPUs. For processes similar to the flowchart of FIG. 8, the same step numbers are assigned and the description is omitted.

[0073] In S1301, the CPU 214 of the precursor diagnosis unit 109 reads out the read image stored in the HDD unit 216 in S1201 as the target image for precursor diagnosis. In S802, the CPU 214 executes the precursor diagnosis process using the read target image. Since the subsequent processes are the same as those in the flowchart of FIG. 8, the description is omitted.

[0074] <Modification Example 2> Next, Modification Example 2 of the first embodiment will be described. In the first embodiment, an example in which the set number is used as the determination condition for the precursor diagnosis target has been described. However, there is no intention to limit the determination condition for the precursor diagnosis target in the present invention to the above. Here, an example in which the determination condition for the precursor diagnosis target is other than the set number will be described.

[0075] When the precursors detected previously are close to the level of image defects, it is possible to predict with higher accuracy by advancing the precursor diagnosis timing and updating the precursor transitions 1001 and 1012 in detail. Therefore, a configuration may be adopted in which the number of sheets, which is the determination condition for the precursor diagnosis target, is reduced according to the size and contrast of the precursors detected previously. By advancing the precursor diagnosis timing and updating the precursor transitions 1001 and 1012 in detail, it is possible to predict with higher accuracy. For example, when the number of sheets up to the level of image defects predicted in S807 is close to the level of image defects such as the last 300 sheets, in this modification example, the next precursor diagnosis is changed from 200 sheets later to 50 sheets later for diagnosis to predict with high accuracy.

[0076] Also, when the deterioration speed until image defects is known in advance by precursors, the precursor diagnosis timing may be changed according to the type of detected precursors. Specifically, in the deterioration prediction table 1100 shown in FIG. 11, when a precursor of a part with a high deterioration speed is detected, the number of determination conditions for precursor diagnosis targets may be reduced to advance the precursor diagnosis timing and track the precursors. For example, while the size deterioration degree per 100 sheets in the developing unit is 2 μm, the size deterioration degree per 100 sheets of the photosensitive drum is as large as 2.5 μm, so it tends to deteriorate quickly. Therefore, when a precursor of the photosensitive drum is detected, by reducing the number of determination conditions for precursor diagnosis targets and advancing the precursor tracking (precursor diagnosis) timing, diagnosis according to the deterioration degree of the precursor becomes possible.

[0077] Furthermore, the determination conditions for precursor diagnosis targets may be a partial range of the page, such as a range limited at the main scanning position or a range where features can be extracted of items where features can be extracted, instead of the entire page. Precursors are characterized by occurring periodically in the same color at the same main scanning position with respect to the precursor-occurring part. An image of the occurrence at the same main scanning position is shown in FIG. 14. For example, assume that a cycle correspondence table in which parts and cycle information correspond is prepared in advance. An example of the cycle correspondence table is shown in FIG. 15.

[0078] Suppose that a scratch has occurred at the main scanning position 1401 in the developing unit, and periodic precursors 1407 have been detected for the target image 1402 of precursor diagnosis. The precursors occur every 37 mm at the main scanning position corresponding to the position 1401. In the target image 1403 of precursor diagnosis after printing 200 sheets of the RIP data 601, precursors also occur in the range 1408 of the same main scanning position. Therefore, a range 1408 narrowed down by the main scanning position instead of the entire image may be used as the determination condition for precursor diagnosis targets. Also, in the target image 1403, from the feature extraction possible map 707 in the plus direction of black, abnormal features in the plus direction of black cannot be extracted in the area 1404, and can only be extracted in the areas 1405 and 1406. Therefore, the area where features can be extracted from the map of items where features can be extracted may be used as the determination condition for precursor diagnosis targets.

[0079] Note that these conditions may be combined such that the "number of sheets" and the "area where feature extractable items can be extracted" are conditions. For example, the conditions for the premonition diagnosis target are that the set number of sheets is 200 sheets and the periodic occurrence position is a place where feature extractable items can be extracted. When the premonition count reaches 200 sheets, if the periodic occurrence position is in an area where feature extraction is impossible for feature extractable items, it is determined as not being a premonition diagnosis target (No in S403), and the premonition count is not changed and the process proceeds to the next process. Also on the next page, the premonition count is 200 sheets, which is equal to the set number of sheets, so it is determined whether it is a premonition diagnosis target based on whether the periodic occurrence position is a feature extractable item and feature extraction is possible. Since the subsequent processing is the same as in the above embodiment, the description is omitted.

[0080] <Second Embodiment> Hereinafter, a second embodiment of the present invention will be described. In the above first embodiment, premonition diagnosis was performed using one premonition diagnosis target image, whereas in this embodiment, an example of performing premonition diagnosis from a plurality of consecutive premonition diagnosis target images will be described. In the above first embodiment, when performing the premonition diagnosis process, the parts where the premonition occurred were specified using the features of the premonition detected from one premonition diagnosis target image. However, depending on the part, a premonition may occur periodically over a plurality of pages. For example, as shown in FIG. 15, when the part and the periodic information correspond, FIG. 16 shows an example where a premonition occurs periodically over a plurality of pages.

[0081] In the example of FIG. 16, when printing on a recording medium A3 with a length in the conveyance direction of 420 mm, since the period of the developing unit is 37 mm, a plurality of precursors periodically occur in the conveyance direction within one sheet. However, since the period of the photosensitive drum 307 is 264 mm, only one precursor 1603 occurs within one sheet of page 1602, so there are cases where the periodic feature cannot be extracted in the feature extraction S805. Also, since periodic precursors 1605 occur on the next page 1604 as well, the periodic feature can be extracted in the feature extraction S805 when including 1603 and 1605. Therefore, in the present embodiment, the case of performing feature extraction of precursors using a plurality of consecutive sheets such as 1602 and 1604 instead of one sheet of 1602 as the diagnostic target image will be described.

[0082] Referring to FIG. 17, the detailed processing procedure of the precursor diagnosis execution process of S404 in the present embodiment will be described. The processes described below are executed by, for example, the CPU 214 of the precursor diagnosis unit 109. Note that they may also 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 those CPUs. For processes similar to the flowchart of FIG. 8, the same step numbers are assigned and the description is omitted.

[0083] First, in the precursor diagnosis target determination S403, the CPU 214 determines that not one sheet but a specified number of consecutive sheets are the precursor diagnosis targets. In the present embodiment, the number of consecutive sheets is set to five consecutive sheets, and the case where the precursor diagnosis is set to be executed every 100 sheets of the determination condition for the precursor diagnosis target will be described. The determination condition for the precursor diagnosis target is to execute the precursor diagnosis for five consecutive sheets every 100 sheets. That is, not only the 100 sheets of the precursor count number stored in the HDD unit 216 but also the 100th to 104th sheets are continuously determined as the diagnostic target images.

[0084] When a precursor is detected in S802, in S1701, the CPU 214 determines whether the precursor detection process S802 for the specified number of five consecutive sheets has ended. If it has ended (Yes in S1701), the process proceeds to S803. If the precursor detection process S802 has not ended for all consecutive precursor 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 no precursor has occurred (No in S803), the process of this flowchart ends.

[0086] In S1702, when a precursor has occurred, the CPU 214 extracts the characteristics of the precursor. In this embodiment, the extraction of periodic characteristics different from those of the first embodiment described above will be described. The CPU 214 extracts periodic characteristics based on the coordinates of the precursor and the continuity of printing. Specifically, for a certain precursor, if there are similar precursors at the periodic destination in the conveyance direction not only within the page but also for subsequent pages, those precursors are determined to be precursors having periodic characteristics. When the extraction of the characteristics of all precursors including the periodic information is completed, the process proceeds to S805.

[0087] As described above, the diagnosis apparatus according to this embodiment diagnoses an image continuously formed on a plurality of recording media as a diagnostic target image. In this way, by performing precursor diagnosis using a plurality of consecutive diagnostic target images instead of a single diagnostic target image, it becomes possible to diagnose precursors even for parts where precursors occur periodically over a plurality of sheets.

[0088] <The Third Embodiment> Hereinafter, the third embodiment of the present invention will be described. In this embodiment, the case where the precursor diagnosis is linked with the inspection system will be described. This embodiment can be realized in combination with the first and second embodiments described above, but the effects of the present invention are not limited to an example of the first and second embodiments. For example, in conjunction with an inspection system that detects abnormalities from a read image of a printed matter, precursor diagnosis may be performed using a part of the read image inspected by the inspection system as a precursor diagnostic image. In this embodiment, an example will be described in which the inspection system is executed in parallel with the precursor diagnosis process by the CPU 214 of the precursor diagnosis unit 109, and the precursor diagnosis process is executed using a part of the read image read by the image reading units 331 and 332.

[0089] <Preliminary diagnosis process> Referring to FIG. 18, the detailed processing procedure of the preliminary diagnosis process in this embodiment will be described. The configuration of the printing system and the flow of the preliminary diagnosis process flow according to this embodiment are the same as those in the first embodiment, and the description thereof will be omitted. For the same processes as the flowcharts of FIGS. 4 and 12, the same step numbers are assigned and the description thereof will be omitted. The processes described below are executed by the CPU 206 of the printing unit 107, the CPU 214 of the preliminary diagnosis unit 109, and the CPU 251 of the external controller 102. Here, a form in which various CPUs cooperate to execute the processes described below will be described, but a form in which an integrated single CPU provided in the image forming apparatus executes all the processes may also be used.

[0090] In S1801, the CPU 214 of the preliminary diagnosis unit 109 sets the image defect level. In this embodiment, an image abnormality at the image defect level is detected as an inspection NG, and an image abnormality that is an inspection OK (not reaching the image defect level) is used as a precursor to diagnose the precursor occurrence location. Specifically, the case where level 7 (510: size 300 μm, contrast 30%) is set as the image defect level from the nine levels of abnormality in FIG. 5 will be described. In this case, precursor detection is performed at level 9 (504: size 100 μm, contrast 10%) where the size is smaller and the contrast is lower than the image defect level. Note that the setting of the precursor level to be detected as an image defect is not limited to level setting. Any method of setting the degree of deterioration that the user cannot tolerate as an image defect may be used, such as a method of specifying a numerical value or a method of selecting an image.

[0091] When the read image is acquired in S1201, in parallel with the preliminary diagnosis processes in S1202 and S1203, in S1802, the CPU 214 executes an inspection process for detecting an image defect using the read image acquired in S1201. Specifically, the CPU 214 reads the read image acquired in S1201 from the HDD unit 216 and detects an image abnormality at the image defect level set in S1801.

[0092] Next, in S1803, the CPU 214 displays the inspection result on the UI display unit 241 of the pre-symptomatic diagnosis unit 109. FIG. 19 is an example of an image showing the results of the inspection process and the pre-symptomatic diagnosis process. When an image defect is detected, the CPU 214 displays a message to that effect in the inspection result 1901 of the UI display unit 241 of the pre-symptomatic diagnosis unit 109. If no defect is detected, the CPU 214 displays "No problem" in the inspection result 1901 of the UI display unit 241 as shown in the result screen 1900. When the detection result is notified, the process proceeds to S405.

[0093] In parallel, in S1202, the CPU 214 determines whether the read image used in the inspection process of S1802 is an image for pre-symptomatic diagnosis. If it is determined that the image is for pre-symptomatic diagnosis, the process proceeds to S1203 where the pre-symptomatic diagnosis process is executed. On the other hand, if it is determined that the image is not for pre-symptomatic diagnosis, the process proceeds to S405. In S1203, the CPU 214 executes the pre-symptomatic diagnosis execution process on the image for pre-symptomatic diagnosis and displays the execution result screen 1910 of the pre-symptomatic diagnosis process in the UI display unit 241 side by side with the inspection result 1901 as the pre-symptomatic diagnosis result 1902. In this embodiment, when there is no pre-symptom (in the case of "No" in S803), "No pre-symptom" is displayed on the UI display unit 241 and then the process proceeds. When there is a pre-symptom, in S809 and S808, the predicted number 1903 predicted in S806 is displayed in the pre-symptomatic diagnosis result 1902 of the UI display unit 241 and then the process proceeds. Also, when automatic repair is not possible (in the case of "No" in S807), the countermeasure 1904 is also displayed in S808.

[0094] Note that the notification of the results of the inspection process and the pre-symptomatic diagnosis process is not limited to the above, and any method that allows the results to be confirmed is acceptable. 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. Also, a display that switches between the inspection result and the pre-symptomatic diagnosis result may be used. When the notification of the results is completed in S803 (No), S809, and S808, the process proceeds to S405.

[0095] As described above, when an image is formed on a recording medium by the image forming unit, the diagnostic apparatus according to the present embodiment performs diagnosis (inspection) of image abnormalities regardless of the determination result of whether or not to execute the precursor diagnosis process. Thereby, by using a part of the read image inspected in the inspection process and setting the precursor detection level according to the inspection level, it becomes possible to utilize the inspection image to perform diagnosis of precursors along with the user's image abnormality level.

[0096] The disclosure of this specification includes the following diagnostic apparatus, its control method, program, and image forming apparatus. (Item 1) A diagnostic apparatus, determination means for determining whether to execute a precursor diagnosis process for detecting a precursor of an abnormality of the image forming means when an image is formed on a recording medium by the image forming means; diagnostic means for executing the precursor diagnosis process on a read image obtained by reading the image formed by the image forming means by a reading means when it is determined that the precursor diagnosis process is to be executed; automatic repair means for causing automatic repair of the image forming means before the precursor of the abnormality reaches an abnormality of a predetermined level when the precursor of the abnormality is detected by the diagnostic means A diagnostic apparatus characterized by comprising. (Item 2) The diagnostic means extraction means for extracting a feature amount for specifying which part of the image forming means the precursor of the abnormality has occurred from the detected precursor of the abnormality; specification means for specifying the part of the image forming means in which the precursor of the abnormality has occurred based on the extracted feature amount The diagnostic apparatus according to Item 1, characterized by comprising. (Item 3) The diagnostic apparatus according to Item 2, characterized in that the feature amount includes size information, shape information, and periodic information of the occurrence of the precursor of the abnormality. (Item 4) The diagnostic means further The diagnostic apparatus according to item 2 or 3, comprising prediction means for predicting the timing at which the detected precursor of the abnormality reaches the abnormality at the predetermined level based on the extracted feature amount. (Item 5) The diagnostic apparatus according to item 4, wherein the prediction means predicts the timing at which the detected precursor of the abnormality reaches the abnormality at the predetermined level based on the feature amount and the identified part. (Item 6) The diagnostic apparatus according to item 4 or 5, wherein the prediction means predicts the number of images formed on the recording medium by the image forming means as the timing at which the detected precursor of the abnormality reaches the abnormality at the predetermined level. (Item 7) The diagnostic apparatus according to any one of items 4 to 6, wherein the diagnostic means causes the display unit to display the diagnostic result of the precursor together with the timing at which the abnormality at the predetermined level is reached. (Item 8) The diagnostic apparatus according to any one of items 1 to 7, wherein the determination means determines to execute the precursor diagnosis process at each timing when the number of images formed on the recording medium by the image forming means reaches a predetermined number, or at the timing when the ongoing precursor diagnosis process ends. (Item 9) The diagnostic apparatus according to item 8, wherein the predetermined number is set according to user input. (Item 10) The diagnostic apparatus according to any one of items 2 to 9, wherein the determination means makes a determination so as to advance the timing of executing the precursor diagnosis process when the previously detected precursor of the abnormality is close to the predetermined level. (Item 11) The diagnostic apparatus according to any one of items 2 to 7, wherein the determination means determines whether to execute the precursor diagnosis process under different determination conditions for each of the identified parts. (Item 12) The diagnostic apparatus according to any one of items 2 to 11, further comprising setting means for setting, as an abnormality of the predetermined level, a level selected according to a user input from among a plurality of levels of image abnormalities. (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 abnormality size and contrast. (Item 14) The diagnostic apparatus according to any one of items 2 to 13, wherein the diagnostic means diagnoses an image formed continuously on a plurality of recording media as an image to be diagnosed. (Item 15) The diagnostic apparatus according to any one of items 2 to 14, wherein the diagnostic means diagnoses an abnormality of the image regardless of a determination result by the determination means when an image is formed on a recording media by an image forming means. (Item 16) The diagnostic apparatus according to any one of items 2 to 15, further comprising reading means for reading a recording media on which an image is formed by the image forming means. (Item 17) A control method for a diagnostic apparatus, comprising: a determination step of determining whether to execute a precursor diagnosis process for detecting a precursor of an abnormality of the image forming means when an image is formed on a recording media by the image forming means; a diagnosis step of executing the precursor diagnosis process on a read image read by the reading means for an image formed by the image forming means when it is determined that the precursor diagnosis process is to be executed; an automatic repair step of causing the image forming means to perform automatic repair before the precursor of the abnormality reaches an abnormality of a predetermined level when the precursor of the abnormality is detected in the diagnosis step; A control method for a diagnostic apparatus, characterized by including the above steps. (Item 18) A program for causing a computer to execute each step in a control method for a diagnostic apparatus, the control method comprising: When an image is formed on a recording medium by an image forming unit, a determination step of determining whether to execute a precursor diagnosis process for detecting a precursor of an abnormality in the image forming unit; When it is determined that the precursor diagnosis process is to be executed, a diagnosis step of executing the precursor diagnosis process on a read image obtained by reading the image formed by the image forming unit by a reading unit; When a precursor of the abnormality is detected in the diagnosis step, an automatic repair step of causing automatic repair of the image forming unit before the precursor of the abnormality reaches an abnormality of a predetermined level A program characterized by including the above. (Item 19) An image forming apparatus, An image forming unit that forms an image on a recording medium; A determination unit that determines whether to execute a precursor diagnosis process for detecting a precursor of an abnormality in the image forming unit when an image is formed on a recording medium by the image forming unit; A diagnosis unit that executes the precursor diagnosis process on a read image obtained by reading the image formed by the image forming unit by a reading unit when it is determined that the precursor diagnosis process is to be executed; An automatic repair unit that causes automatic repair of the image forming unit before the precursor of the abnormality reaches an abnormality of a predetermined level when the precursor of the abnormality is detected by the diagnosis unit An image forming apparatus characterized by comprising the above. (Item 20) The image forming apparatus according to item 19, further comprising the reading unit that reads a recording medium on which an image has been formed by the image forming unit. (Item 21) A diagnostic apparatus, A setting unit that sets the number of sheets; A diagnostic unit that executes a precursor diagnosis process for detecting a precursor of an abnormality in the image forming unit on a read image obtained by reading the image formed by the image forming unit by a reading unit each time the number of images formed on a recording medium by the image forming unit reaches the number of sheets set by the setting unit; When the precursor of the abnormality is detected by the diagnosis means, an automatic repair means for causing the image forming means to perform automatic repair, and A diagnostic apparatus comprising the same.

[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 apparatus via a network or a storage medium, and causing one or more processors in a computer of the system or apparatus to read and execute the program. Further, it can also be realized by a circuit (for example, ASIC) that realizes one or more functions.

[0098] The invention is not limited to the above embodiments, and various changes and modifications can be made without departing from the spirit and scope of the invention. Therefore, claims are attached to disclose the scope of the invention.

Description of Reference Numerals

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

Claims

Claim 1 A diagnostic apparatus, comprising: determination means for determining whether to execute precursor diagnosis processing for detecting a precursor of an abnormality in the image forming means when an image is formed on a recording medium by the image forming means; diagnosis means for executing the precursor diagnosis processing on a read image obtained by reading, by a reading means, an image formed by the image forming means when it is determined that the precursor diagnosis processing is to be executed; automatic repair means for causing automatic repair of the image forming means before the precursor of the abnormality reaches an abnormality of a predetermined level when the precursor of the abnormality is detected by the diagnosis means A diagnostic apparatus characterized by comprising the above. Claim 2 The diagnostic means includes: extraction means for extracting a feature amount for specifying which part of the image forming means the precursor of the abnormality has occurred from the detected precursor of the abnormality; specification means for specifying a part of the image forming means in which the precursor of the abnormality has occurred based on the extracted feature amount The diagnostic apparatus according to claim 1, characterized by comprising the above. Claim 3 The diagnostic apparatus according to claim 2, wherein the feature amount includes size information, shape information, and periodic information of the occurrence of the precursor of the abnormality of the precursor of the abnormality. Claim 4 The diagnostic means further includes: [[ID= ​ ​ ​ ​ ​ ​ ​ ​ ​ The diagnostic apparatus according to claim 8, wherein the predetermined number is set according to user input.

10. The diagnostic apparatus according to claim 8, wherein the determination means makes a determination so as to advance the timing of executing the precursor diagnosis process when the precursor of the abnormality detected previously is close to the predetermined level.

11. The diagnostic apparatus according to any one of claims 2 to 7, wherein the determination means determines whether to execute the precursor diagnosis process under different determination conditions for each of the specified parts.

12. The diagnostic apparatus according to claim 8, further comprising setting means for setting, as the abnormality of the predetermined level, a level selected according to user input from among levels of a plurality of image abnormalities.

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

14. The diagnostic apparatus according to claim 8, wherein the diagnostic means diagnoses an image formed continuously on a plurality of recording media as an image to be diagnosed.

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

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

17. A control method for a diagnostic apparatus, comprising: a determination step of determining whether to execute a precursor diagnosis process for detecting a precursor of an abnormality of an image forming means when an image is formed on a recording medium by the image forming means; a diagnosis step of executing the precursor diagnosis process on a read image read by the reading means for an image formed by the image forming means when it is determined that the precursor diagnosis process is to be executed; and an automatic repair step of causing automatic repair of the image forming means before the precursor of the abnormality reaches an abnormality of a predetermined level when the precursor of the abnormality is detected in the diagnosis step. A control method for a diagnostic apparatus, characterized by including the above steps.

18. A program for causing a computer to execute each step in a control method for a diagnostic apparatus, wherein the control method includes: When an image is formed on a recording medium by an image forming unit, a determination step of determining whether to execute a precursor diagnosis process for detecting a precursor of an abnormality in the image forming unit; When it is determined to execute the precursor diagnosis process, a diagnosis step of executing the precursor diagnosis process on a read image obtained by reading the image formed by the image forming unit by a reading unit; When a precursor of the abnormality is detected in the diagnosis step, an automatic repair step of causing the image forming unit to perform automatic repair before the precursor of the abnormality reaches an abnormality of a predetermined level; A program characterized by including the above.

19. An image forming apparatus, comprising: An image forming unit that forms an image on a recording medium; A determination unit that determines whether to execute a precursor diagnosis process for detecting a precursor of an abnormality in the image forming unit when an image is formed on the recording medium by the image forming unit; A diagnosis unit that executes the precursor diagnosis process on a read image obtained by reading the image formed by the image forming unit by a reading unit when it is determined to execute the precursor diagnosis process; An automatic repair unit that causes the image forming unit to perform automatic repair before the precursor of the abnormality reaches an abnormality of a predetermined level when the precursor of the abnormality is detected by the diagnosis unit; An image forming apparatus characterized by comprising the above.

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

21. A diagnostic apparatus, comprising: A setting unit that sets the number of sheets; A diagnosis unit that executes a precursor diagnosis process for detecting a precursor of an abnormality in the image forming unit on a read image obtained by reading the image formed by the image forming unit by a reading unit every time the number of images formed on the recording medium by the image forming unit reaches the number of sheets set by the setting unit; An automatic repair unit that causes the image forming unit to perform automatic repair when the precursor of the abnormality is detected by the diagnosis unit; A diagnostic apparatus characterized by comprising the above.

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