JP2007232952A - Image forming device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an image forming device which can detect a pre-abnormal state before solid abnormalities happen and inform the user of the pre-abnormal state with countermeasures against the abnormalities corresponding to the pre-abnormal state. <P>SOLUTION: This image forming device measures the time required to transfer paper sheet form a first point to a second point on the transfer path. The device compares the result with the predetermined reference (designed value T1). When the measured value is larger than the reference and exceeds the predetermined tolerance (T2) but does not reach the abnormal value (jam timer value T4), the device detects the generation of a pre-abnormal state and informs the user with the countermeasures to take against the abnormalities corresponding to the pre-abnormal state by printing. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a sheet conveying apparatus that conveys a sheet, and an image forming apparatus such as a copying machine, a facsimile machine, and a printer including the sheet conveying apparatus.

  2. Description of the Related Art Conventionally, a method for detecting the occurrence of a paper jam based on the passage time between adjacent sensors installed in an image forming apparatus is known (see Patent Document 1). In this method, the paper conveyance time between adjacent sensors is measured, and it is determined that a paper jam has occurred when the measured value is larger than the theoretical value.

  In addition, taking into consideration that the conveyance speed of the paper changes due to the wear of the conveyance roller, the adhesion of paper dust to the conveyance roller, etc., the sheet passage time of the sheet conveyance speed sensor is measured, and this passage time becomes a predetermined value. To reduce the frequency of paper jams by changing the rotation speed of the stepping motor in this way, or to display a message indicating that it is time to replace when the motor rotation speed reaches a predetermined value Etc. have been proposed (see Patent Document 2).

  In Patent Document 3, the time for which a sheet passes through a sensor is measured, and the ratio between the number of sheets conveyed within a predetermined passage time and the number of sheets conveyed outside a predetermined passage time is a predetermined ratio. There has been proposed a method of reducing the occurrence frequency of paper jams by extending the operation time of the paper conveying means when the time is exceeded.

  As a conventional consumable management method, as described in Patent Document 4, there is a method of displaying and confirming the number of times an arbitrary part is used after switching the apparatus main body to a confirmation-only mode.

  As a method of predicting a failure, as described in Patent Document 5, firstly, a limit value of the operation limit is set, and then another limit value that reaches before the limit value is set, and the limit value is exceeded. A method has been proposed in which the number of times is counted to recognize that the operation limit has been reached and a failure is predicted.

As a method of predicting the life of the consumables and notifying the user when the replacement time is reached, as described in Patent Document 6, the replacement time of the consumables is predicted from the usage time and the consumption amount of the consumable parts, There has also been proposed a method for alerting the user when the preset exchange time has been reached.
Japanese Patent Laid-Open No. 1-187149 Japanese Patent Laid-Open No. 5-16461 JP 2000-238921 A JP-A-2-32370 JP-A-8-154161 JP 2003-186649 A

  In the techniques described in Patent Documents 1 to 3, a paper jam is determined from the paper passage time between adjacent sensors, and a life extension measure is taken or the conveyance speed is kept constant. No consideration is given to user operations and countermeasures after notifying the user of that fact. Even in actual products, there are some products that notify when the time that the paper passes between the sensors falls within the range corresponding to the paper jam, but the response after the notification is left to the user. It is inconvenient for an unfamiliar user because it is necessary to search for the corresponding page by referring to the manual or to clear the paper jam by an appropriate operation method.

  In the technique described in Patent Document 4, the operation method and the confirmation procedure are complicated, such as the need to enter the dedicated mode once, and it is necessary to know the operation method in order to enter the dedicated mode. , Not all users could easily check.

  As described in Patent Document 5, in the method of providing a limit value and predicting the replacement time of consumables, simply predicting the failure or replacement time, a method for canceling the failure or a notification that leads to the subsequent operation of the user is issued. It is troublesome and inconvenient for users who are not familiar with the device.

  As described in Patent Document 6, in the method of predicting the remaining life from the use time of the consumable parts and warning that when the replacement time is reached, the user only needs to give a warning and then how the user responds to the warning. The only way to recognize whether it was the best solution was to find the best solution from among the many manuals.

  The present invention has been made in such a background, and its purpose is to detect a pre-abnormal state before the occurrence of a definite abnormality and notify the user of the pre-abnormal state, as well as an abnormality corresponding to the pre-abnormal state. It is an object of the present invention to provide an image forming apparatus capable of informing a coping method at the time of occurrence.

  An image forming apparatus according to the present invention measures the time required for transporting a sheet from a first point to a second point on a transport path in an image forming apparatus that transports a sheet on which an image is recorded along the transport path. The time measurement means and the measurement value obtained by this measurement are compared with the specified reference value. If the measurement value exceeds the reference value, the excess time exceeds the predetermined tolerance, but the measurement value is specified. Pre-abnormality state detection means for detecting the occurrence of a pre-abnormal state that does not reach the abnormal value, and when the pre-abnormal state is detected, a countermeasure to that effect and when an abnormality corresponding to the pre-abnormal state occurs And notifying means for notifying the user.

  As described above, in the present invention, the measured value of the time does not reach the specified abnormal value, but the state where the excess time exceeding the reference value exceeds the allowable range is detected as the pre-abnormal state. When this pre-abnormal state is detected, the user is notified not only of that but also a coping method. This notification method is preferably based on print output.

  In one embodiment, the notification means counts the number of occurrences of the pre-abnormal state, and performs the notification for the first time when the count value reaches a predetermined number or more. As a result, it is possible to prevent useless notifications in the case where the state before the abnormality is temporarily accidentally caused.

  When the pre-abnormal state is detected, there may be provided means for adding an excess of the measured value with respect to the reference value to the specified abnormal value. Thereby, when the conveyance time tends to be extended due to secular change or the like, it is possible to delay the time when the jam detection is confirmed by adding to the paper conveyance jam timer as the time measuring means.

  In the image forming apparatus according to the present invention, it is not necessary to detect an abnormal state yet, but it is possible to detect a pre-abnormal state and notify the user early, and to notify the user including a countermeasure. Thus, the user can easily deal with the problem. That is, the recovery operation can be performed quickly, and the image forming apparatus can be used efficiently with little time loss.

  In addition, by notifying the user of how to deal with the abnormal state through printout, it is possible to quickly confirm and accurately execute the countermeasure when the abnormality occurs.

  DESCRIPTION OF EXEMPLARY EMBODIMENTS Hereinafter, preferred embodiments of the invention will be described in detail with reference to the drawings.

  First, FIG. 1 shows a schematic configuration inside the image forming apparatus according to the present embodiment, and an outline of conveying a sheet will be described. This image forming apparatus includes a main body cassette 21 and a multi-tray 22 as a mechanism for placing paper to be fed. Each of them includes a cassette paper feed roller 1 and a multi paper feed roller 2 for feeding paper.

  The paper conveyed by these paper feed rollers is detected by the pre-registration sensor 11 and then sent out by the pre-registration roller 3. At this time, the pre-registration sensor 11 determines whether or not the leading edge of the sheet reaches the pre-registration sensor 11 until a predetermined time has elapsed from the start of paper feeding. If the paper arrives within a certain time, the jam timer is cleared. However, if the leading edge of the paper that has started feeding does not reach the pre-registration sensor 11 even after a certain period of time has passed, it is determined that a paper jam (jam) has been detected after a certain period of time has passed, Is notified to the user.

  A latent image is formed on the photosensitive drum 4 on the sheet fed by the pre-registration roller 3 on the basis of the read document image information, the print target image information received from the host computer, or the like. This latent image is visualized as a toner image in a developing device 9 (not shown). The toner image on the photosensitive drum 4 is transferred onto the sheet by the potential difference between the potential charged by the charging roller 6 and the potential applied to the transfer roller 5. The sheet on which the toner image has been transferred is sent to the next fixing step.

  In the fixing process, the sheet on which the unfixed toner image is sent out from the transfer roller 5 is fixed on the sheet by heat and pressure by the fixing device 7 and sent out to the paper discharge unit.

  The paper discharged from the fixing device 7 is detected by the paper discharge sensor 12 and is discharged to the outside by the paper discharge roller 8. Thus, the printing operation for one sheet is completed. Also at this time, the paper discharge sensor 12 determines whether or not the paper arrives until a predetermined time elapses after the leading edge of the paper is detected by the pre-registration sensor 11. If the paper reaches the paper discharge sensor 12 within a predetermined time, the timer is cleared. If the paper does not arrive within the predetermined time, it is determined that a paper jam (jam) has been detected, and the user is notified. Be notified.

  FIG. 2 shows a schematic configuration of control hardware of the image forming apparatus according to the present embodiment. This configuration shows a configuration example of a printer that prints print data received from a host computer. The control unit 100 includes a CPU, a memory, an input / output device, and the like, and controls each unit of the device according to a control program stored in the memory. A host interface (IF) unit 101 is a part that is controlled by the control unit 100 and receives image data to be printed from a host computer. In the copying machine, instead of the host interface unit 101, a document reading unit (not shown) for converting a document into read image data is provided. The FAX machine includes a communication unit (not shown) that receives facsimile data from a communication line instead of the host interface unit 101. Various sensors 103 are sensors arranged in each part of the apparatus, and output detection signals to the control unit 100. The various sensors 103 include a pre-registration sensor 11, a paper discharge sensor 12, a temperature detection element (not shown), and the like. The paper feeding / conveying unit 107 is a part that feeds and conveys a recording material by a motor, a clutch, and the like (not shown), and is controlled by the control unit 100. In the present embodiment, the image forming unit 109 corresponds to a laser scanner (not shown), a developing device (9), a transfer roller 5 and the like in addition to the photosensitive drum 4, and is controlled by the control unit 100. The fixing device 110 (corresponding to 7 in FIG. 1) includes a fixing roller having a built-in heater, a fixing film, a pressure roller, and the like, and is also controlled by the control unit 100 to fix the unfixed toner image on the paper to the paper. . The operation panel 104 includes an input unit through which a user inputs instructions and data to the control unit 100 and a display unit that displays information that the control unit 100 informs the user. The timer unit 111 includes, for example, an RTC (Real Time Clock), and has a function of managing date and time in addition to a timer function based on a reference clock.

  In the present embodiment, the function of the time measuring unit 111 detects jams by the respective jam timers of the pre-registration sensor 11 and the paper discharge sensor 12, and the paper discharge sensor after the paper passes through the pre-registration sensor 11. The time until the paper passes through 12 is measured. FIG. 3A shows a case where the paper transport time T from the pre-registration sensor 11 to the paper discharge sensor 12 is a design value (a prescribed reference value) T1. (T1, T2, and T3, which are time variables, are shown along the horizontal axis in this figure. The horizontal axis represents the position, and the length of the arrow with the time variable is proportional to the actual time length. On the other hand, FIG. 3B shows a state in which the paper transport time T from the pre-registration sensor 11 to the paper discharge sensor 12 is delayed beyond the design value T1. Even if the paper transport time T from the pre-registration sensor 11 to the paper discharge sensor 12 is increased, the paper transport time T is a prescribed abnormal value, which is lower than the jam timer value T4 that is supposed to be jammed, and When the fixed time T2 that is allowable than the original design value T1 is exceeded by a time that is smaller than the time T3 (that is, the paper transport is not determined to be jammed but is delayed beyond the allowable level), the user is informed. And print out a manual on how to deal with and recover from paper jams that may occur. As a result, the user can quickly and accurately recover from the jammed state. The time T3 is a value that satisfies T4 = T1 + T2 + T3.

  In addition, by notifying the occurrence of a subsequent jam before the jam occurs, the user can grasp the state of the machine. As a result, it is possible to know a jam that will occur soon before executing a job with a large number of sheets and a coping method, and to remove the cause before the job.

  4 detects a delay in the sheet conveyance time from the sheet passage time by the first sheet conveyance sensor and the second sheet conveyance sensor in the sheet conveyance path of FIG. It is a flowchart for demonstrating the process for recognizing that the delay has arisen. This process is realized by the CPU in the control unit described above reading and executing the program in the ROM. The same applies to other flowcharts described later.

  First, in step S1, when the paper is recognized by the pre-registration sensor that is the paper conveyance sensor in FIG. 1, the timer of step S2 starts counting. After the timer count is started, the arrival of the paper at the paper discharge sensor is monitored at a fixed period (S3), and after detecting the paper, the count value at that time is saved internally as definite information (S4).

  Next, in the arrival time determination process, the saved timer count value is compared with a prescribed reference value T1 stored therein as a theoretical value, and as a result, it is determined whether or not the time is over (S5). . This reference value T1 is a value for determining whether or not a paper conveyance delay has occurred in a range where jamming does not occur.

  Thereafter, a jam determination for determining whether or not a jam has occurred is performed (S6). At this time, occurrence of a jam can be determined based on whether or not the count value exceeds a specified abnormal value (jam timer value T4). If a jam has occurred, a jam notification is performed (S8). The timer count value at this time is invalidated. However, if it is determined that it is not a jam, the fact that a delay has occurred due to the paper delay determination process is stored internally as determination information (S7).

  FIG. 5 is a flowchart for explaining the processing up to the notification to the user and the printing when it is determined that a delay has occurred but not a jam by the processing of FIG.

  First, the notification setting is checked in the user setting (S11). If the setting does not require notification, the paper delay information is cleared (S12), and the process is terminated. If notification is necessary in the user settings, it is confirmed whether or not a paper delay has actually occurred (S13). The information used for the determination here is the paper delay confirmation information described with reference to FIG.

  If the delay is confirmed in the paper delay determination process in step S13, the number of times that the paper delay has occurred is counted (S14). This count number is used as a criterion. If there is no paper delay at the time of the determination in step S13, the process ends without doing anything.

  The “predetermined number of times” in the determination process in step S15 may be set by the user. This makes the frequency of notification to the user variable. A user who wants to know the possibility of jam occurrence with high accuracy sets a relatively small “predetermined number of times”. If the user does not need frequent notification, the frequency of notification to the user can be reduced by setting the “predetermined number of times” relatively large.

  When it is determined that the number is “predetermined number of times” or more, the fact that the jam is near is displayed (notified) (S16). At this time, a warning is displayed together with what kind of jam is likely to occur. At the same time, information (for example, a part of a manual) indicating how to deal with a jam that will occur if this state continues is printed and notified to the user. This saves the user the trouble of searching for the corresponding page in a thick manual, and can immediately obtain useful information for the event that has occurred. In addition, since notification on a paper basis is performed by print output, even if an actual abnormality occurs later, it can be used immediately.

  By the way, even when the jam is not actually jammed in the conveyance path, if the count value exceeds the jam timer value, the jam is determined. However, the operation can be continued as long as the paper is not jammed even if it is determined to be jammed. In such a case, it is desirable not to stop the operation while the job is being executed. Therefore, when it is determined that the occurrence of a jam is close as described above, as shown in FIG. 6, the jam timer value T4 is increased by a predetermined time value (for example, a delay time Δt exceeding the jam timer value T4). The jam timer value T4 is temporarily changed. Thereby, the possibility that it is determined that a jam has occurred decreases.

  FIG. 7 is a flowchart describing a process of adding a delay in the conveyance time to the jam timer value when a delay in the sheet conveyance time is detected. The “delay” corresponds to an excess of the measured value with respect to the design value T1 of the paper conveyance time.

  First, it is determined whether or not a delay in the sheet conveyance time as described in step S7 of FIG. 4 has occurred (S21). If it does not occur, this process is terminated without doing anything. If there is a delay in the paper conveyance time, it is determined whether this is the first time in one job (S22). If it is not the first time, this process is terminated. The determination of whether or not it is the first time is to prevent the later-described step S23 from being executed repeatedly in one job.

  The jam timer value T4 is delayed from the design value by a predetermined time (in this example, the amount ΔT in which the conveyance time is delayed) (S23). Thereby, it is possible to delay the time for determining the jam. The changed jam timer value T4 is reset to the original value at the end of the job.

  Next, a second embodiment of the present invention will be described.

  As shown in FIG. 8, in the second embodiment, a server 211, printers 213, 215, and 217 as image forming apparatuses, clients 212, 214, and the like are connected to each other via a communication network 210 such as a LAN. It relates to a system comprising 216 and the like. When a print instruction is given from a client (referred to as client A) on the network 210 to a printer (referred to as printer A) on the same network 210, the printer A that is the target of print instruction is displayed on the print screen of the client A. Direct instructions can be given.

  If the printer A on this network fails, since there are other printers (printer B and printer C) on the same network, printing can be continued using these. However, if such other printers B and C do not exist and only the printer A exists, printing cannot be continued if the printer A fails and stops. Therefore, if the failure is near to occur, notify the user to that effect and notify the user that the failure is near and the recovery measures from the abnormal state that will occur later. Can respond immediately.

  For example, in the case of waste toner full detection shown in FIG. 9, the amount of waste toner in the waste toner bottle 53 is detected by a waste toner full sensor. As the waste toner full sensor, a photosensor including a light emitting unit 51 and a light receiving unit 52 is used, and the waste toner is shielded between the two to detect the fullness of the waste toner.

  The control unit 100 monitors the waste toner full sensor when the power is turned on and at the time of paper discharge. When the number of printed sheets after the detection of the full toner waste reaches the cumulative number N1, it is determined as the waste toner full notice time. Then, a warning is displayed on the display unit. At this time, a warning is displayed to the user, and an operation to be performed by the user with respect to “waste toner full detection” which will occur in the future and a description of a coping method are printed. If there are several options for the user's coping method, the type is displayed or printed out, and the method that the user wants to deal with is input. This determines the final user and machine response to the failure warning.

  For example, in the case of waste toner full detection, when a warning of waste toner full notification is received, when the waste toner full state is still continued after printing N2 sheets (N2> N1), The printer is determined to be full and cannot be printed. In other words, the state of the waste toner detected by the waste toner full sensor is not a complete full state in a strict sense but a state in which a certain amount of waste toner can be additionally accumulated.

  Therefore, the user has an option of selecting whether to continue printing until “a state where printing is not possible”, or “to replace waste toner bottle” or “disposal of waste toner”. By letting the user know these options, the user can select a response method by himself.

  Also, by printing out the “waste toner bottle replacement” method and “waste toner disposal” method, it is possible to cancel the warning method by which the user should cancel it. Can understand.

  FIG. 10 is a flowchart showing a processing sequence for performing this warning display. First, at least at a predetermined time, after confirming the stability of the sensor state, the sensor is monitored at a constant period. When the light shielding detection output of the waste toner full sensor is detected (S31, Yes), it is checked whether or not the light shielding detection output is a failure (abnormal) due to a failure of the waste toner full sensor (S32). If it is not Fail, the number of printed sheets is checked, and after printing the prescribed value N1 (S34, Yes), a warning of occurrence of an abnormal state is given and the contents describing the countermeasure are printed (S35).

  If a Fail state has occurred in step S32, an abnormal state warning display is not performed by this sequence, and the user is notified of the generated Fail state by display or the like (S33).

  FIG. 11 is a diagram for explaining an example of a user interface when performing print output in step S35. The contents notified by the user by printing or display are the generated contents indicating the “abnormal state that has occurred” and the “handling method”. When there are some options in the “handling method”, the options are also numbered and notified to the user as shown in the example in the figure. The user can know the action to be taken thereafter in the content that is finally printed out by selecting the target method to be adopted from this option and inputting the number. The contents to be printed out may be a coping method including such options or the contents of a user manual.

  In addition, when there is no information on the optimum coping method in the printer and the printer is connected to the Internet, a manual or information on it is obtained from a homepage (HP) on the Internet. The method of printing may be used.

  In an image forming apparatus in which a fatal abnormal state has occurred, the occurrence of the event and subsequent countermeasures cannot be printed. However, as shown in FIG. 8, this is the case when the apparatus is connected to a network. When the same model of the same manufacturer exists in the same network, the command form is the same because the printer driver of the same model is used. In this case, the printer driver that has issued a print request for the occurrence of the failure is notified of the type of the abnormal state that has occurred and a subsequent countermeasure.

  “Fatal abnormality” means, for example, communication abnormality, no toner cartridge, waste toner cartridge full detection, no paper, various doors open, fan failure, optical system failure, fixing device failure, motor failure, clutch failure, paper jam Detection, thermistor high temperature detection, high-voltage output abnormality, option connection device abnormality, paper feeding device abnormality, power supply abnormality, discharge paper full detection, etc.

  The printer driver that received the notification of the occurrence of an abnormality from the printing device that issued the print request temporarily stores the notification content internally, and then the same manufacturer with the same command form on the network to which it is connected Check if the same model exists.

  If the same model of the same manufacturer in the same network and the same manufacturer can be recognized, a print request is sent to the printer, and the abnormal state related to the device in which the previous abnormal state has occurred and how to deal with it Is printed out.

  FIG. 12 is a command sequence diagram for printing information related to an apparatus in which an abnormal state has occurred when the same model of the same manufacturer exists on the same network. In this example, it is assumed that when a print instruction is output to a printer A from a printer driver of a certain client, the printer A fails during printing. The fact that a failure has occurred is returned from the printer A to the client, and the information is stored in the client. In order to print a countermeasure for the printer A in which a failure has occurred, a “print execution confirmation” command is issued to the same model of the same manufacturer in the same network, and a “printable response” as a response is issued. It is determined that printing is possible for the printers B and C returned by the response.

  From among the devices that are determined to be printable, the execution device that executes printing is determined. For example, by issuing a print request to the printer B that has returned a response for the first time, a print request is issued to output information about the occurrence of the faulty printer A and a countermeasure for the cancellation. When there are a plurality of devices capable of printing, the device that prints is not limited to the device that has returned the response first. For example, the user may select and instruct one of them.

  In the second embodiment, the abnormal state to be detected may be an event related to the occurrence of a jam as described in the first embodiment.

  With the above-described configuration and processing, whatever situation occurs, it is not fatal enough to stop the operation of the image forming apparatus, or it is not fatal enough to stop the operation. In response to the occurrence of a situation that would be abnormal when detecting this, the occurrence event and the subsequent response method are printed out and notified to the user, thereby clarifying the response method and prompting the response.

  The preferred embodiments of the present invention have been described above, but various modifications and changes other than those mentioned above can be made.

  For example, the detection of an abnormal state is not limited to the above case, and in a system that determines the occurrence of an abnormality when the signal is detected multiple times, an abnormal signal is detected but has not yet been detected multiple times. By recognizing a state (not an abnormality), the user can be notified in a predetermined state before the occurrence of the abnormality.

1 is a diagram showing a schematic internal configuration of an image forming apparatus according to an embodiment of the present invention. FIG. 2 is a diagram showing a schematic configuration of control hardware of the image forming apparatus according to the embodiment of the present invention. In the embodiment of the present invention, it is a diagram for explaining the paper conveyance time from the pre-registration sensor to the paper discharge sensor. 7 is a flowchart for explaining a process for recognizing that there is a delay in conveyance although jamming does not occur immediately in the embodiment of the present invention. FIG. 5 is a flowchart for explaining processing up to notification and printing to a user when it is determined that a delay has occurred but not jammed by the processing of FIG. 4. It is explanatory drawing of the jam timer value in embodiment of this invention. It is a flowchart describing the process which adds the delay part of conveyance time to a jam timer value in embodiment of this invention. It is a figure which shows the schematic system configuration | structure in the 2nd Embodiment of this invention. It is a figure which shows the structural example of the waste toner full sensor for detecting a waste toner full tank as an example of the abnormal state in the 2nd Embodiment of this invention. It is a flowchart showing the process sequence at the time of performing the warning display of this invention. It is explanatory drawing in the case of performing printing output in step S35 of FIG. FIG. 6 is a command sequence diagram for printing information regarding a printer in which an abnormal state has occurred from the same model of the same manufacturer connected to the network.

Explanation of symbols

8 ... paper discharge roller 9 ... developing device 11 ... pre-registration sensor 12 ... paper discharge sensor 21 ... main body cassette 22 ... multi-tray 51 ... light emitting unit 52 ... light receiving unit 53 ... waste toner bottle 100 ... control unit 101 ... host interface unit 103 ... Various sensors 104 ... Operation panel 107 ... Paper feed / conveying part 109 ... Image forming part 110 ... Fixing device 111 ... Timekeeping part 210 ... Communication network 211 ... Servers 212, 214, 216 ... Clients 213, 215, 217 ... Printer

Claims (5)

In an image forming apparatus that conveys a sheet for recording an image along a conveyance path,
Time measuring means for measuring the time required for paper conveyance from the first point to the second point on the conveyance path;
The measured value obtained by this measurement is compared with a specified reference value.If the measured value exceeds the specified reference value, the excess time exceeds the predetermined tolerance, but the measured value is not the specified abnormal value. Pre-abnormal state detection means for detecting occurrence of a pre-abnormal state that does not reach,
An image forming apparatus comprising: notification means for notifying a user of a countermeasure to be taken when an abnormality corresponding to the pre-abnormal state occurs when the pre-abnormal state is detected.   The image forming apparatus according to claim 1, wherein the notification unit counts the number of occurrences of the pre-abnormal state, and performs the notification for the first time when the count value reaches a predetermined number or more.   The image forming apparatus according to claim 1, wherein the notification unit notifies the user of at least the coping method by printout.   3. The image forming apparatus according to claim 1, further comprising means for adding an excess of the measured value with respect to the reference value to the specified abnormal value when the pre-abnormal state is detected.   5. The time measuring means has a paper transport jam timer, the addition is performed only once per job, and the paper transport jam timer is reset to the original value at the end of the job. Image forming apparatus.

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