JP5343468B2 - Motor driving device, image forming apparatus, motor driving method, and computer program - Google Patents

Description

  The present invention relates to a motor drive device that detects a motor load abnormality and a motor abnormality and copes with these abnormalities, an image forming apparatus including the motor drive device, a motor drive method, and a motor drive method for executing the computer with a computer. Relating to computer programs.

In recent years, office machines such as copiers and printers require high productivity. Therefore, it is not acceptable to stop the machine due to a failure or to deteriorate the image quality, and it is necessary to detect the failure quickly and resolve it in advance. It has been. In this regard, for example, Patent Document 1 describes an invention that makes it possible to diagnose a motor or gear failure without adding a special failure detection circuit. According to the present invention, a failure that occurs in a device having a rotational drive mechanism including a rotational drive member that rotates by receiving a current supply and a power transmission member that transmits the rotational drive force of the rotational drive member to another member is provided. It is a failure diagnosis apparatus for diagnosing each component member constituting a rotation drive mechanism by analyzing a feature quantity of an operation signal indicating a rotation operation state of the rotation drive member output along with the rotation operation of the rotation drive member The fault diagnosis is performed on
JP 2007-212719 A

  In the invention described in Patent Document 1, a failure diagnosis is performed on each component member constituting the rotation drive mechanism by analyzing the feature quantity of the operation signal of the rotation drive member. If the machine cannot be used for a while without waiting for arrival, printing may continue in a state where the quality is deteriorated even though the machine can be used. That is, in this known example, the failure diagnosis is performed by analyzing the feature amount such as the rise time or the frequency for the encoder signal, but after the failure is diagnosed, the failure details are only notified. Sometimes downtime occurs.

  Therefore, the problem to be solved by the present invention is to prevent the occurrence of downtime by detecting the cause of the failure and dealing with the cause before the occurrence of the failure that causes downtime. .

In order to solve the above problems, the present invention is detected by a motor for driving a load, motor driving means for driving the motor, motor speed detecting means for detecting the rotational speed of the motor, and the motor speed detecting means. Motor speed fluctuation detecting means for detecting a motor speed fluctuation based on the rotation speed of the motor, an abnormality determining means for detecting an abnormal rotation of the motor based on a detection result of the motor speed fluctuation detecting means, and the motor driving means. Motor speed control means for controlling the rotational speed of the motor via the motor, and the motor speed control means is set to a frequency near the gain crossover frequency and higher than the gain crossover frequency by the abnormality determination means than a reference value. If that is significant fluctuation component is detected, those as the fluctuation component due to the influence of the speed variation does not exceed Geinzero Wherein the lower the gain of the motor speed control means.

In the embodiments described later, the motor is the intermediate transfer belt drive motor 150, the motor drive means is the motor drive section 140, the motor speed detection means is the speed detection section (encoder) 170, and the motor speed fluctuation detection means is the speed fluctuation. the detection unit 132, the abnormality judging means to the abnormality determination unit 133, the motor speed control means to the speed control unit 131, corresponding, respectively Re it.

According to the present invention, it is possible to prevent the occurrence of downtime caused by the abnormality that has occurred.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings.

  FIG. 1 is a diagram showing a schematic configuration of an entire image forming apparatus according to an embodiment of the present invention. In FIG. 1, the image forming apparatus according to the present embodiment includes a printer unit 1, a scanner unit 2, an automatic document feeding unit 3, and a paper feeding unit 4. The unit 2 is provided on the printer unit 1 and the automatic document feeding unit 3 is provided on the scanner unit 2, and is configured as a digital multi-function peripheral MFP having a plurality of functions such as a printer function, a copying function, and a facsimile function. .

  The printer unit 1 is an indirect transfer type tandem type color printer. Each of the YMCK image forming stations 11Y, 11M, 11C, and 11K (generally indicated by reference numeral 11), the intermediate transfer belt 12, and each station. The primary transfer units 13Y, 13M, 13C, and 13K (generally indicated by reference numeral 13) provided, the secondary transfer unit 14 and the secondary transfer unit 14 provided below the primary transfer unit 13 are provided. Basically, the conveying unit 15, the fixing unit 16 provided on the downstream side of the conveying unit 15, the duplex unit 17 provided on the downstream side of the fixing unit 16, and the writing unit 18 that performs optical writing for each of the stations 11. It is configured.

  The scanner unit 2 irradiates the original on the contact glass with illumination light from a light source, guides the reflected light to the CCD, and optically reads the original. The automatic document feeder 3 automatically feeds the document placed on the document feeder on the contact glass of the scanner unit 2. The paper feeding unit 4 includes four paper feeding stages. The transfer paper is drawn from one of the paper feeding stages, sent from the vertical conveyance path to the registration roller 19 immediately before the secondary transfer unit 14, and from the registration roller 19 to the intermediate transfer. The transfer paper is fed in time with the image on the belt 12.

  In this embodiment, the image forming stations for the respective colors are juxtaposed in the order of Y, M, C, and K from the upstream side in the rotation direction of the intermediate transfer belt 12, but in the order of K, C, M, and Y, The order of C, M, Y, and K is also set as appropriate according to the design conditions, and the configuration in the figure is merely an example.

  The image forming station 11 includes a photosensitive drum and a charging unit, a developing unit, a primary transfer unit, a cleaning unit, and a charge eliminating unit provided along the outer periphery of the photosensitive drum. An exposure unit that is exposed by laser light from the scanner unit 2 is provided between the two. Note that these structures are known structures.

  In image forming apparatus MFP configured as described above, scanner unit 2 scans a document while irradiating the document with illumination light emitted from a light source, and reads an image of reflected light from the document with a three-line CCD sensor. . The read image data is subjected to image processing such as scanner γ correction, color conversion, image separation, and gradation correction processing in the image processing unit, and then sent to the image writing unit 18. The image writing unit 18 modulates the driving of an LD (laser diode) according to the image data. In the image forming station 11, a latent image is written by a laser beam from the LD onto a uniformly charged rotating photosensitive drum, and a toner is attached by a developing unit to be visualized.

  The toner image formed on the photosensitive drum for each color is transferred onto the intermediate transfer belt 12 for each color by the primary transfer unit 13. In the case of a full-color copy on the intermediate transfer belt 12, four color toners of YMCK are sequentially superimposed to form a full-color toner image. When the YMCK toner image is superimposed and the transfer process to the intermediate transfer belt 12 is completed, the transfer paper that has been stopped at the registration roller 19 is sent out in time with the leading edge of the image, and the secondary transfer unit 14 A full-color toner image is transferred from the intermediate transfer belt 12 onto the transfer paper. The transfer paper onto which the toner has been transferred is sent to the fixing unit 16 through the conveyance unit 15, and is thermally fixed by the fixing roller and the pressure roller and discharged.

  The intermediate transfer belt 12 is wound around a driving roller 12a and two driven rollers 12b and 12c, and a predetermined tension is obtained by a tension roller 12d. As a result, the driving force of the driving roller 12a is transmitted to the intermediate transfer belt 12, and the intermediate transfer belt 12 rotates.

  When an image is also formed on the back side of the transfer paper, it is conveyed from the fixing unit 16 to the double-sided unit 17 side, the front and back sides are reversed, and the transfer paper is sent again to the registration roller 19 side. The image is ejected after transfer paper and fixing.

  Hereinafter, the control configuration of the present embodiment will be described separately for each example.

  FIG. 2 is a block diagram showing a control circuit of image forming apparatus MFP in Example 1 of the present embodiment. This control circuit is a control configuration for driving the intermediate transfer belt.

  2, the control circuit includes a main control unit (main body control unit) 100, a motor control unit 130, a motor drive unit 140, and a speed detection unit (encoder) 170 of the image forming apparatus MFP main body. The encoder 170 is a motor drive unit. The rotation of the gear reduction mechanism 160 of the intermediate transfer belt drive motor 150 driven by the motor 140 is detected. An operation unit 110 is connected to the main control unit 100 and also controls a load 120 other than the intermediate transfer belt drive motor 150.

The motor control unit 130 includes a speed control unit 131, a speed fluctuation detection unit 132, and an abnormality determination unit 133. The speed control unit 131 includes an addition unit 131a, a gain multiplication unit 131b, a loop filter 131c, and a PMW unit 131d. The motor driving unit 140 includes a pre-driver 141 and an FET 142, and the pre-driver 141 further includes a three-phase output control unit 141a and a preamplifier 141b.

  A target speed is output from the main control unit 100 to the speed control unit 131, a speed control signal is input from the speed control unit 131 to the motor drive unit 140, and the drive shaft on which the intermediate transfer belt 12 is wound around from the motor drive unit 140. A drive signal is output to the motor 150 that drives the motor 12a. The rotation of the intermediate transfer belt drive motor 150 detects the rotation of the reduction gear 160 of the gear reduction mechanism 160 by the encoder 170 and feeds back the rotation signal to the speed control unit 131.

  That is, the intermediate transfer belt drive motor 150 is driven by the motor control unit 130 and the motor drive unit 140 of the motor control board in accordance with a speed instruction from the main control unit 100. The speed instruction from the main control unit 100 is generally instructed by the CLK signal, and based on the instructed signal, the gain multiplication unit 131b sequentially performs gain multiplication and the filter processing unit 131c performs filter processing. Is converted to PWM by the PWM unit 131d, converted into a three-phase output signal by the three-phase output control unit 141a of the pre-driver 141, and the intermediate transfer belt drive motor 150 is driven by the FET 142 (or transistor).

  The speed of the intermediate transfer belt drive motor 150 is controlled by the speed control unit 15 by feeding back the detection value of the encoder 170 to the addition unit 131a and the speed fluctuation detection unit 132. In this embodiment, the detection signal of the encoder 170 is subjected to FFT (Fast Fourier Transform) processing by the speed fluctuation detecting unit 132, and the speed fluctuation is extracted for each frequency. The abnormality determination unit 133 sequentially observes speed fluctuations and, when an abnormality is detected, instructs the gain multiplication unit 131b to change the gain.

  The main control unit 100 includes a central control unit (CPU) (not shown), and the CPU develops a program stored in a ROM (not shown) in a RAM (not shown) and executes the RAM while using the RAM as a work area. As a result, various controls are executed by the main control unit 100.

  FIG. 3 is a diagram illustrating an example of a measured value of speed fluctuation for each frequency component after FFT processing in the speed fluctuation detection unit 132. FIG. 3 shows, for example, the detection of the speed fluctuation for each frequency component after the FFT processing. In FIG. 3, the horizontal axis represents the frequency, and the vertical axis represents the rate of speed fluctuation when the frequency is a parameter.

  FIG. 4 is a diagram showing the measured value of the speed fluctuation for each frequency component after the FFT processing in the speed fluctuation detecting unit 132 and the effect when changing the gain. The figure shows the frequency characteristics (open loop characteristics) of the control controller of the speed controller 131. In order to explain the influence of speed fluctuation due to disturbance, the speed fluctuation component is also shown in the same figure.

  In the figure, up to the crossing frequency XHz is the control band that can be controlled by the controller, but when a speed fluctuation of frequency YHz slightly exceeding the control band (shown as a speed fluctuation component due to disturbance) occurs, the gain increases. And gain 0 is exceeded again. At this time, since the phase delay exceeds -180 °, the control becomes unstable and oscillation occurs. In order to prevent oscillation, it is necessary to sufficiently separate the speed fluctuation frequency YHz and the crossing frequency XHz. Therefore, in this embodiment, the gain is lowered as indicated by a chain line in FIG. 4 so that the fluctuation component Y and the tolerance frequency X are kept away from the region where the cross frequency XHz and the fluctuation component frequency YHz are not adversely affected by the control.

  FIG. 5 is a flowchart illustrating a processing procedure performed by the main control unit 100 and the motor control unit 130 in the first embodiment. When the start signal is sent from the main control unit 100, the motor control unit 130 starts the rotation of the intermediate transfer belt drive motor 150, detects the speed by the encoder 170 (step S101), and becomes the speed instruction value (target value). Feedback control is performed. In the feedback control, the fed-back encoder signal is subjected to FFT by the speed fluctuation detecting unit 132 and converted to a frequency component (step S102). Next, in the abnormality determination unit 133, the speed fluctuation between the crossing frequency XHz and the frequency YHz larger than the crossing frequency is higher than the normal state (for example, Z = 0.2% or more—shown by a thick solid line in FIG. 3). When (value) is detected, it is determined that an abnormality has occurred (step S103-yes), and an instruction to lower the gain is given to the gain multiplier 131b (step S104). Since the value for decreasing the gain varies depending on the mechanical mechanism, a value is set in advance so that the image quality does not deteriorate extremely even if the gain is decreased. Also, since the setting value of the Y value varies depending on the mechanism, the Y value is set by performing simulation during design.

  FIG. 6 is a flowchart illustrating a processing procedure performed by the main control unit 100 and the motor control unit 130 in the second embodiment. The control circuit itself is the same as that of the first embodiment shown in FIG.

  In FIG. 6, steps S101 to S103 are processed in the same manner as in the first embodiment, but the abnormality determination unit 133 detects a value in which the speed fluctuation between the cross frequency XHz and the frequency YHz larger than the cross frequency is higher than the normal state. In such a case, it is determined that an abnormality has occurred (step S103-yes), and an instruction to lower the gain is given to the gain multiplier 131b. Here, the gain to be lowered is performed a plurality of times, for example, 3/4 times, 1/2 times, 1/4 times the current gain, and speed fluctuations at the time of each gain setting are detected (steps S104a, S105). , S106, S107, S108, S109). Among the plurality of times, the one with the best speed fluctuation state is set as the gain after the next time (step S110). For example, the gain has the lowest speed fluctuation value, the average of the speed fluctuations in all frequency bands, the lowest speed fluctuation, and the speed fluctuation in the area where banding is easily visible when the image is displayed. Choose from one of the smaller ones.

  Other parts not specifically described are configured in the same manner as in the first embodiment and function in the same manner.

  FIG. 7 is a block diagram illustrating a control circuit of image forming apparatus MFP in the third embodiment. In the third embodiment, while the abnormality determination unit 133 notifies the gain multiplication unit 131b of an abnormality in the first embodiment, the abnormality determination unit 133 notifies the main control unit 100 of the abnormality. The other parts are configured in the same way as in the first embodiment.

  In this third embodiment, the encoder signal is subjected to FFT (Fast Fourier Transform) processing by the speed fluctuation detection unit 132, the speed fluctuation is extracted for each frequency, and the speed fluctuation is sequentially observed by the abnormality determination unit 133 to detect the abnormality. If this happens, the main control unit 100 is notified. FIG. 8 is a flowchart illustrating a processing procedure performed by the main control unit 100 and the motor control unit 130 according to the third embodiment.

  In FIG. 8, between step S201 and step S203, the same process as in the first embodiment is executed, and the abnormality determination unit 133 is a value in which the speed fluctuation between the cross frequency XHz and the frequency YHz larger than the cross frequency is higher than the normal state. If (for example, 0.2% or more as an example of performing precise control) is detected, it is determined that an abnormality has occurred (step S203-yes), and the main control unit 100 is notified of the abnormality (step S204). ). When receiving the notification of abnormality, the main control unit 100 controls the entire machine to be driven at half speed (step S205).

  FIG. 9 is a diagram illustrating an example of a measured value of the speed fluctuation for each frequency component after the FFT processing in the third embodiment and the effect at the half speed. The horizontal axis represents frequency and the vertical axis represents gain. As can be seen from the figure, by controlling to drive at half speed, disturbance that is higher than the crossing frequency XHz and is in an uncontrollable band can be included in the control band. As a result, the disturbance can be suppressed by the control of the controller.

  In the third embodiment, the productivity is lowered, but the control parameter is not changed, so that no side effect that deteriorates the image quality is generated.

  Other parts not specifically described are configured in the same manner as in the first embodiment and function in the same manner.

  FIG. 10 is a block diagram illustrating a control circuit of image forming apparatus MFP in the fourth embodiment. In the fourth embodiment, the abnormality determination unit 133 notifies the gain multiplication unit 131b of the abnormality in the first embodiment, whereas the abnormality determination unit 133 notifies the abnormality to the filter 131e of the speed control unit 131. It is. The filter 131e is provided after the loop filter 131c and before the PWM unit 131d, and has a function of reducing the sensitivity only in an abnormal frequency band. Other parts are configured in the same manner as in the first embodiment and function in the same manner.

  FIG. 11 is a flowchart illustrating a processing procedure performed by the main control unit 100 and the motor control unit 130 according to the fourth embodiment. Steps S301 to S303 are processed in the same manner as steps S101 to S103 in the first embodiment. However, in the abnormality determination unit 133, the speed fluctuation between the crossing frequency XHz and the frequency YHz larger than the crossing frequency is higher than the normal state. Is detected (step S303-yes), the filter 131e is notified of the abnormality. The filter 131e lowers the sensitivity of only the gain of the frequency where the abnormality has occurred with respect to the output of the loop filter 131c (step S304). As a result, the gain can be prevented from rising and oscillation can be prevented.

  FIG. 12 is a diagram illustrating an example of a measured value of the speed fluctuation for each frequency component after the FFT processing in the fourth embodiment and the effect of the filter. The horizontal axis represents frequency and the vertical axis represents gain. As can be seen from the figure, it is possible to reduce the sensitivity of the speed fluctuation component due to the disturbance by adding the characteristic shown by A in FIG. 12 only in the frequency band where the fluctuation is generated by the filter 131e. Oscillation can be prevented.

  FIG. 13 is a block diagram illustrating a control circuit of image forming apparatus MFP in the fifth embodiment. The fifth embodiment is a combination of the first and second embodiments. When the abnormality determination unit 133 determines that an abnormality has occurred, the abnormality is notified to the gain multiplication unit 131a and the main control unit 100. Other parts are configured in the same manner as in the first embodiment and function in the same manner.

  As described above, when the abnormality notification is performed to the gain multiplication unit 131a and the main control unit 100, the operation unit 13 is notified of the abnormality, or the serviceman is notified of the abnormality through a network line, a telephone line, or the like as necessary. be able to.

  FIG. 14 is a flowchart illustrating a processing procedure performed by the main control unit 100 and the motor control unit 130 in the fifth embodiment. Steps S401 to S404 are processed in the same manner as steps S101 to S104 of the first embodiment. After the gain is lowered by a certain amount in step S404, an abnormality is notified to the main control unit 100 (step S405). An abnormality is notified to the service person, or the abnormality is notified to the service person through a network line or a telephone line. For a model having a purge tray, if it is during the passage of paper when the occurrence of an abnormality is detected, the paper being passed is discharged to the purge tray (step S406).

  Thereby, in the first embodiment, what is processed in the image forming apparatus MFP can be notified to the outside to assist in the subsequent maintenance, or the occurrence of a sheet jam caused by the occurrence of an abnormality can be prevented. .

As described above, according to this embodiment,
(1) Changes in the drive system due to abnormalities in the load of the motor drive system, wear of the mechanical mechanism, etc. are detected by frequency analysis of the encoder signal that detects the rotation speed of the motor. When it is an uncontrollable region, the process of placing the abnormality under its own control is executed and the abnormality is dealt with, so that the occurrence of downtime caused by the abnormality can be prevented.

(2) When the motor drive system is applied to an image forming apparatus MFP such as a copying machine, a printer, or a digital multi-function peripheral, the drive system changes due to abnormal load on the drive system for image formation, wear of the mechanical mechanism, etc. Is detected by frequency analysis of the encoder signal that detects the rotation speed of the motor, and if an abnormality is detected in a specific frequency band, the gain is changed without stopping the machine, the motor rotation speed is decreased, and the filter process is performed. By executing processing such as reducing abnormal fluctuation components, image quality deterioration can be prevented.
There are effects such as.

  In addition, this invention is not limited to this embodiment, All the technical matters contained in the technical thought described in the claim are object.

1 is a diagram illustrating a schematic configuration of an entire image forming apparatus according to an embodiment of the present invention. FIG. 3 is a block diagram illustrating a control circuit of the image forming apparatus in Example 1 of the present embodiment. It is a figure which shows an example of the measured value of the speed fluctuation | variation for every frequency component after the FFT process in the speed fluctuation | variation detection part of FIG. It is a figure which shows the effect at the time of the measured value of the speed fluctuation | variation for every frequency component after the FFT process in the speed fluctuation | variation detection part of FIG. 2, and a gain change. 3 is a flowchart illustrating a processing procedure performed by a main control unit and a motor control unit according to the first embodiment. 10 is a flowchart illustrating a processing procedure performed by a main control unit and a motor control unit according to the second embodiment. 6 is a block diagram illustrating a control circuit of an image forming apparatus in Embodiment 3. FIG. 10 is a flowchart illustrating a processing procedure performed by a main control unit and a motor control unit according to a third embodiment. It is a figure which shows the example of the effect value at the time of the example of the measured value of the speed fluctuation | variation for every frequency component after the FFT process in Example 3, and a half speed. FIG. 10 is a block diagram illustrating a control circuit of an image forming apparatus in Embodiment 4. 10 is a flowchart illustrating a processing procedure performed by a main control unit and a motor control unit according to a fourth embodiment. It is a figure which shows the example of the measured value of the speed fluctuation | variation for every frequency component after the FFT process in Example 4, and the effect of a filter. FIG. 10 is a block diagram illustrating a control circuit of an image forming apparatus in Embodiment 5. 10 is a flowchart illustrating a processing procedure performed by a main control unit and a motor control unit according to a fifth embodiment.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Printer part 2 Scanner part 3 Automatic document feeding part 4 Paper feed part 12 Intermediate transfer belt 12a Drive roller 12b, 12c Driven roller 100 Main control part 110 Operation part 130 Motor control part 131 Speed control part 132 Speed fluctuation detection part 133 Abnormality Judgment unit 140 Motor drive unit 141 Pre-driver 142 FET
150 Intermediate transfer belt drive motor 160 Deceleration mechanism 170 Speed detector (encoder)

Claims (12)

A motor driving the load;
Motor driving means for driving the motor;
Motor speed detecting means for detecting the rotational speed of the motor;
Motor speed fluctuation detecting means for detecting a speed fluctuation of the motor based on the rotational speed of the motor detected by the motor speed detecting means;
An abnormality determining means for detecting an abnormal rotation of the motor based on a detection result of the motor speed fluctuation detecting means;
Motor speed control means for controlling the rotational speed of the motor via the motor driving means;
With
The motor speed control means, said abnormality determining means places that there is a large fluctuation component than the reference value at a higher frequency than in the vicinity and the gain crossover frequency of the gain crossover frequency is detected by case, the influence of the velocity fluctuation A motor drive device characterized by lowering the gain of the motor speed control means so that the fluctuation component does not exceed zero gain . The motor drive device according to claim 1,
When the motor speed control means lowers the gain of the motor control means, it is a process of switching the gain to be reduced a plurality of times and selecting a gain with the best speed fluctuation state . A motor driving the load;
Motor driving means for driving the motor;
Motor speed detecting means for detecting the rotational speed of the motor;
Motor speed fluctuation detecting means for detecting a speed fluctuation of the motor based on the rotational speed of the motor detected by the motor speed detecting means;
An abnormality determining means for detecting an abnormal rotation of the motor based on a detection result of the motor speed fluctuation detecting means;
Motor speed control means for controlling the rotational speed of the motor via the motor driving means;
With
The motor speed control means, when the abnormality determination means detects that there is a fluctuation component larger than a reference value in the vicinity of the gain crossover frequency and higher than the gain crossover frequency, the frequency of the fluctuation component is the crossover frequency. A motor driving device characterized by lowering the rotational speed of the motor so as to be lower than the frequency A motor driving the load;
Motor driving means for driving the motor;
Motor speed detecting means for detecting the rotational speed of the motor;
Motor speed fluctuation detecting means for detecting a speed fluctuation of the motor based on the rotational speed of the motor detected by the motor speed detecting means;
An abnormality determining means for detecting an abnormal rotation of the motor based on a detection result of the motor speed fluctuation detecting means;
Motor speed control means for controlling the rotational speed of the motor via the motor driving means;
With
When the abnormality determining means detects that there is a fluctuation component larger than a reference value at a frequency near the gain crossover frequency and higher than the gain crossover frequency, the motor speed control means A motor driving device characterized in that the sensitivity is reduced only in the frequency band of the fluctuation component so that the component does not exceed zero gain . In the motor drive unit according to any one of claims 1 to 4 ,
The abnormality determining means, when detecting an abnormality in rotation of the motor, notifies the main body control section that outputs a target speed command to the motor speed control means that an abnormality has occurred . An image forming apparatus comprising the motor drive device according to claim 1. An image forming apparatus comprising the motor drive device according to claim 3, wherein the speed of the entire device is reduced when an abnormality is detected . The image forming apparatus according to claim 6 or 7 ,
An image forming apparatus , wherein an abnormality is displayed on an operation unit when an abnormality is detected. The image forming apparatus according to claim 6 or 7 ,
An image forming apparatus, wherein when an abnormality is detected , the remote fault diagnosis and maintenance system is notified through the communication line that an abnormality has occurred . The image forming apparatus according to any one of claims 6 to 9 ,
An image forming apparatus , wherein a sheet being printed is discharged to a purge tray when an abnormality is detected. A motor driving the load;
Motor driving means for driving the motor;
Motor speed detecting means for detecting the rotational speed of the motor;
Motor speed fluctuation detecting means for detecting a speed fluctuation of the motor based on the rotational speed of the motor detected by the motor speed detecting means;
An abnormality determining means for detecting an abnormal rotation of the motor based on a detection result of the motor speed fluctuation detecting means;
Motor speed control means for controlling the rotational speed of the motor via the motor driving means;
A motor driving method for a motor driving device comprising:
When the abnormality determining means detects that there is a fluctuation component larger than a reference value in the vicinity of the gain crossover frequency and higher than the gain crossover frequency, the fluctuation component does not exceed the gain zero due to the influence of the speed fluctuation. And a motor driving method characterized by lowering the gain of the motor speed control means . A motor driving the load;
Motor driving means for driving the motor;
Motor speed detecting means for detecting the rotational speed of the motor;
Motor speed fluctuation detecting means for detecting a speed fluctuation of the motor based on the rotational speed of the motor detected by the motor speed detecting means;
An abnormality determining means for detecting an abnormal rotation of the motor based on a detection result of the motor speed fluctuation detecting means;
Motor speed control means for controlling the rotational speed of the motor via the motor driving means;
A computer program for causing a computer to execute drive control of a motor of a motor drive device comprising:
When a large fluctuation component than the reference value at a higher frequency than in the vicinity and the gain crossover frequency of the gain crossover frequency it is detected that by the abnormality determining means, so that the fluctuation component does not exceed Geinzero the influence of the velocity fluctuation A computer program for causing the motor speed control means to function so as to lower the gain of the motor speed control means .

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