JP2014112138A - Image forming apparatus - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an image forming apparatus that easily specifies an abnormal component causing an abnormal phenomenon.SOLUTION: An image forming apparatus includes: an abnormality detection unit 304 that detects an abnormal phenomenon on a resist roller; a vibration detection unit 302 that detects vibration occurring due to a stepping motor 205 driving the resist roller and other driving components; and an abnormality diagnosis unit 305. The abnormality diagnosis unit 305 stops the operation of the other driving components than the stepping motor 205 when an abnormal phenomenon is detected in the resist roller, and diagnoses the presence of abnormality in the stepping motor 205 from the vibration of the stepping motor 205 detected while the operation of the other driving components is stopped.

Description

  The present invention relates to an image forming apparatus that can detect abnormality of a component.

  Image forming apparatuses are becoming more multi-colored, faster, and more functional, and the configuration is complicated. For this reason, when an abnormal phenomenon such as a jam, an error, or a deterioration in image quality occurs in the image forming apparatus, a component (hereinafter referred to as “abnormal part”) in which an abnormal operation, failure, or damage has occurred. It is difficult to identify easily. The early identification of abnormal parts leads to a reduction in repair time and is important in the operation of the image forming apparatus.

  Patent Document 1 discloses an invention for identifying an abnormal part by comparing the sound pressure of an operating sound during operation with a reference value. Patent Document 2 discloses an invention in which an abnormal part is specified by operating a driving part constituting the apparatus in order for a predetermined time with respect to the apparatus in which the abnormal noise is generated.

JP 2006-208074 A JP 2007-114272 A

  When an abnormal phenomenon occurs in a drive unit composed of multiple drive parts and the abnormal parts are identified, it is difficult to identify the abnormal parts from vibration and sound pressure because the multiple drive parts are driven simultaneously. is there. When the driving components are sequentially operated as in Patent Document 2, the operation of the driving unit is stopped and re-driven after the occurrence of an abnormal phenomenon. However, the operating environment and load conditions of the drive components change due to re-driving, and the abnormal phenomenon is not always reproduced. In that case, it is still difficult to identify abnormal parts.

  In view of the above problems, an object of the present invention is to easily identify an abnormal component that causes an abnormal phenomenon.

  In order to solve the above-described problems, the present invention is an image forming apparatus that forms an image on a recording medium, and includes a target component, a first component that cooperates with the target component, and a second component. Detection means for detecting an abnormality related to processing performed by the target part and the first part, a physical quantity detection means for detecting a predetermined physical quantity, and when the abnormality is detected, the operation of the second part is stopped. Diagnosing means for diagnosing the presence or absence of abnormal operation of the first part from the physical quantity detected by the detecting means while the operation of the second part is stopped.

  In the present invention as described above, when an abnormal phenomenon occurs, only the target component and the first component are operated to diagnose whether there is an abnormality in the first component. Can be easily and reliably performed.

1 is a configuration example diagram of an image forming apparatus. The block diagram of a control unit. The figure showing the connection relationship of each functional block comprised by CPU201, a stepping motor, a conveyance sensor, and a vibration sensor. (A)-(d) is explanatory drawing of a vibration waveform and a FFT waveform. The flowchart of the process which specifies the abnormal component of 1st Embodiment. The flowchart of the process which specifies the abnormal component of 2nd Embodiment. The flowchart of the process which specifies the abnormal component of 2nd Embodiment. Sectional drawing of a fixing device. Explanatory drawing of the twist of a pressure roller and a fixing film. The figure showing the connection relation of each functional block comprised in CPU, a brushless motor, and a vibration sensor. The flowchart of the process which specifies the abnormal component of 3rd Embodiment.

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

[First Embodiment]
FIG. 1 is a structural example diagram of an electrophotographic tandem type image forming apparatus 1.
The image forming apparatus 1 includes an image forming unit 1Y that forms a yellow image, an image forming unit 1M that forms a magenta image, an image forming unit 1C that forms a cyan image, and a black image. Includes an image forming unit 1Bk. The four image forming units 1Y, 1M, 1C, and 1Bk are arranged in a line at regular intervals. A laser exposure unit 7 is provided below the image forming units 1Y, 1M, 1C, and 1Bk. Below the laser exposure unit 7, a paper feeding unit such as a cassette 17 for storing the printing paper P and a manual feed tray 20 is arranged. From the paper supply unit, the printing paper P is transported by a transport path. In addition, a secondary transfer roller 12 and a fixing device 16 are provided at the transport destination in the transport path.

The configuration of the image forming units 1Y, 1M, 1C, and 1Bk will be described using the image forming unit 1Y as an example. Since the other image forming units 1M, 1C, and 1Bk have the same configuration as the image forming unit 1Y, description thereof is omitted.
The image forming unit 1Y includes a drum-type electrophotographic photosensitive member (hereinafter referred to as “photosensitive drum”) 2a as an image carrier. Around the photosensitive drum 2a, a primary charger 3a, a developing device 4a, a transfer roller 5a as a transfer means, and a drum cleaner 6a are arranged.

  The photosensitive drum 2a is a negatively charged OPC photosensitive member, has a photoconductive layer on an aluminum drum base, and is rotationally driven at a predetermined speed in a clockwise direction in FIG. 1 by a driving device (not shown). . The primary charger 3a uniformly charges the surface of the photosensitive drum 2a to a predetermined negative potential with a charging bias applied from a charging bias power source (not shown). After charging, the photosensitive drum 2a is exposed by the laser beam from the laser exposure unit 7, whereby an electrostatic latent image is formed on the photosensitive drum 2a.

  The developing device 4a contains yellow toner. The yellow toner is attached to the electrostatic latent image formed on the photosensitive drum 2a and developed (visualized) as a toner image. The developing device 4b stores cyan toner, the developing device 4c stores magenta toner, and the developing device 4d stores black toner, and development is performed for each color.

  The transfer roller 5a is disposed so as to be in contact with the photosensitive drum 2a via the intermediate transfer belt 8 at the primary transfer portion 32a. The toner image on the photosensitive drum 2a is transferred onto the intermediate transfer belt 8 by the transfer roller 5a coming into contact with the photosensitive drum 2a. By the image forming units 1Y, 1M, 1C, and 1Bk, the toner images of the respective colors are transferred onto the intermediate transfer belt 8 in a superimposed manner. The drum cleaner 6a is constituted by a cleaning blade or the like, and scrapes off transfer residual toner remaining on the photosensitive drum 2a to clean the surface of the photosensitive drum 2a.

  The laser exposure unit 7 includes a laser that emits laser light according to image data, a polygon lens, a reflection mirror, and the like. The laser exposure unit 7 exposes each of the photosensitive drums 2a, 2b, 2c, and 2d to form an electrostatic latent image of each color corresponding to the image data on the surface of the photosensitive drums 2a, 2b, 2c, and 2d. .

The intermediate transfer belt 8 is disposed on the upper surface side of each of the photosensitive drums 2a, 2b, 2c, and 2d, is stretched between the secondary transfer counter roller 10 and the tension roller 11, and is rotationally driven in the direction of arrow A. Is done. The intermediate transfer belt 8 is made of a dielectric resin such as a polycarbonate, a polyethylene terephthalate resin film, a polyvinylidene fluoride resin film, or the like.
The secondary transfer counter roller 10 is disposed so as to be in contact with the secondary transfer roller 12 via the intermediate transfer belt 8. The toner image transferred to the intermediate transfer belt 8 by the image forming units 1Y, 1M, 1C, and 1Bk is transferred to the printing paper P conveyed from the paper feeding unit by the secondary transfer roller 12 and the secondary transfer counter roller 10. The A belt cleaner 13 that removes and collects transfer residual toner remaining on the surface of the intermediate transfer belt 8 is disposed outside the intermediate transfer belt 8 and in the vicinity of the secondary transfer counter roller 10.
As described above, an image is formed on the printing paper P with each color toner.

  The paper feeding unit includes a pickup roller (not shown) that feeds the printing paper P one by one from the cassette 17 or the manual feed tray 20. The printing paper P sent out from the pickup roller is opposed to the secondary transfer roller 12 and the secondary transfer roller by the paper feed roller 18 and the registration roller 19 in accordance with the timing of image formation by the image forming units 1Y, 1M, 1C, and 1Bk. It is sent to the contact portion of the roller 10.

  The fixing device 16 includes a fixing film 16a including a heat source such as a ceramic substrate having a heater therein, and a pressure roller 16b (this roller may include a heat source in some cases). The fixing device 16 thermocompresses the toner image transferred onto the printing paper P by the fixing film 16a and the pressure roller 16b. In front of the fixing device 16, a pre-fixing guide 34 that guides the printing paper P to the nip portion 31 of the fixing film 16 a and the pressure roller 16 b is provided. After the fixing device 16, an outer paper discharge roller 21 for discharging the printing paper P discharged from the fixing device 16 to the outside of the image forming apparatus 1 is provided. The printing paper P is discharged by the outer paper discharge roller 21 after the toner image is fixed by the fixing device 16.

A vibration sensor 206 is provided in the vicinity of the conveyance path between the paper supply roller 18 and the registration roller 19. The vibration sensor 206 is a sensor for detecting an abnormal vibration level during paper conveyance. From the vibration sensor 206, vibration data representing the state of vibration is output.
A vibration sensor 220 for detecting an abnormal vibration level of the fixing device 16 is provided in the vicinity of the fixing device 16. The vibration sensor 220 also outputs vibration data representing the state of vibration.
The vibration sensors 206 and 220 include, for example, piezoelectric elements, detect vibrations in the conveyance path, and generate an amount of current proportional to the detected vibrations. Vibration data is generated according to this current. An abnormality can be detected by the output level and frequency component of the vibration data.

  A conveyance sensor 218 that detects the printing paper P that has reached the outer conveyance path is provided in the vicinity of the conveyance path between the registration roller 19 and the secondary transfer roller 12. Image formation is started based on the detection timing of the printing paper P by the transport sensor 218. If the printing paper P is not detected within a predetermined time, it is determined that a jam has occurred (an abnormal phenomenon has occurred).

  The operation of the image forming apparatus 1 is controlled by the control unit 102 shown in FIG. The control unit 102 is built in the image forming apparatus 1.

The CPU 201 controls the operation of the entire image forming apparatus 1 by executing a program stored in the ROM 203. The CPU 201 communicates with other components in the control unit 102 via the bus. The RAM 204 is a main storage device used as a working storage area when the CPU 201 executes processing.
In addition to the above programs, the ROM 203 stores various information that is read when an abnormality occurs, which will be described later. For example, it stores information representing the relationship between cooperating parts such as a motor and a roller driven by the motor. By storing such a relationship, for example, when an abnormal phenomenon caused by the operation of the roller is detected, the motor related to this roller can be easily specified. The ROM 203 stores information for specifying the cause of the abnormal phenomenon from physical quantities such as vibration and sound detected after the abnormal phenomenon is detected. Note that these pieces of information other than the program stored in the ROM 203 may be separately stored in a rewritable storage device such as a flash memory. In the case of storing in such a storage device, it is possible to cope with a change in physical quantity due to a time-dependent change in driving components or the use environment of the image forming apparatus 1.

The I / O interface 216 is connected to each load of the image forming apparatus 1 such as a motor 207, a clutch 208, a solenoid 209, and a sensor 210 that drive a paper feed system, a transport system, and an optical system. . The CPU 201 communicates with each load via the I / O interface 216.
Each of the developing devices 4a, 4b, 4c, and 4d includes a toner sensor 211 that detects the amount of toner inside. The detection result of the toner sensor 211 is input to the CPU 201 via the I / O interface 216. Detection results by the vibration sensors 206 and 220 and the conveyance sensor 218 are also input to the CPU 201 via the I / O interface 216. Signals from switches 212 for detecting the home position of each load, the open / close state of the door of the image forming apparatus 1, and the like are also input to the CPU 201 via the I / O port 216.
The high voltage unit 213 outputs a high voltage to a load that requires a high voltage, such as the primary chargers 3a, 3b, 3c, and 3d, and the developing devices 4a, 4b, 4c, and 4d. The high voltage unit 213 outputs a high voltage in response to an instruction input from the CPU 201 via the I / O interface 216. Laser light output from the laser exposure unit 7 is detected by a beam detection sensor 214 which is a light receiving sensor. The detection result is input to the CPU 201 via the I / O port 216.
The stepping motor 205 is a motor for driving the paper supply roller 18 and the registration roller 19 that convey paper. The brushless motor 219 is a motor for driving the pressure roller 16b. These motors drive each roller in response to an instruction input from the CPU 201 via the I / O interface 216.

  A PWM (Pulse Width Modulation) circuit 215 outputs a PWM signal corresponding to the image data to the laser exposure unit 7. The laser exposure unit 7 can emit laser light according to the image data by the PWM signal.

  The controller 217 is connected to the CPU 201 so as to be capable of serial communication, and exchanges image data output to the image forming units 1Y, 1M, 1C, and 1Bk. The operation unit 222 is connected to the controller 217 and includes display means and key input means for performing various settings. Such an operation part 222 is implement | achieved by the display apparatus provided with the touch panel, for example.

  The CPU 201 sequentially inputs and outputs data via the I / O interface 216 and executes an image forming operation. In addition, the CPU 201 detects that an abnormal phenomenon has occurred in each part of the image forming apparatus 1 based on signals from the sensors 210, the toner sensor 211, the vibration sensors 206 and 229, the transport sensor 218, and the switches 212. Identify the abnormal part.

  FIG. 3 is a diagram illustrating a functional block executed by the CPU 201 and a connection relationship between the stepping motor 205, the conveyance sensor 218, and the vibration sensor 206. Each function of the CPU 201 forms an abnormality detection device realized by the CPU 201 reading a program from the ROM 203 and executing it.

  The motor drive module 303 controls the operation of the stepping motor 205. The stepping motor 205 uses the motor drive module 303 to start and end driving of the paper feed roller 18 and control the rotation speed.

  The abnormality detection unit 304 determines the occurrence of an abnormal phenomenon such as a jam from the detection result of the transport sensor 218. For example, if the conveyance sensor 218 does not detect the printing paper P within a predetermined time from the start of the operation of the stepping motor 205 by the motor driving module 303, the abnormality detection unit 304 determines that an abnormal phenomenon has occurred.

  The abnormality identification unit 307 identifies a component related to the occurrence of the abnormal phenomenon from the abnormal phenomenon detected by the abnormality detection unit 304. The identification of the component is performed based on information representing the relationship of the cooperative components stored in the ROM 203. In this example, the abnormality detection unit 304 determines an abnormal phenomenon from the detection delay of the printing paper P by the transport sensor 218. For this purpose, the stepping motor 205 as the first component that drives the paper feed roller 18 for conveying the printing paper P as the target component is specified.

The vibration detection unit 302 analyzes vibration data in the vicinity of the transport path detected by the vibration sensor 206 and detects a physical quantity generated in the vicinity of the transport path.
The abnormality diagnosis unit 305 receives a report about a component related to the occurrence of the abnormal phenomenon specified by the abnormality specifying unit 307, and stops the operation of another component (second component) other than this component. Then, the cause of the abnormal phenomenon is specified from the result detected and analyzed by the vibration detection unit 302 for a predetermined time while other parts are stopped. In this example, the abnormality diagnosis unit 305 stops driving of motors other than the stepping motor 205 specified by the abnormality specifying unit 307, and from the vibration data analyzed by the vibration detection unit 302 during the stop, the stepping motor 205 Determine if there are any abnormalities.
The vibration detection unit 302 and the abnormality diagnosis unit 305 perform analysis and identification of factors based on information for identifying the cause of the abnormal phenomenon stored in the ROM 203, for example.
The identified vibration factor is displayed on the display means of the operation unit 222 via the controller 217, thereby notifying the user.

FIG. 4 shows the vibration waveform detected by the vibration sensor 206 and the vibration waveform by FFT (Fast
It is explanatory drawing with the FFT waveform which carried out Fourier Transform (fast Fourier transform). 4A to 4D, a waveform a is a vibration waveform detected by the vibration sensor 206. In the waveform a, the horizontal axis represents time, and the vertical axis represents vibration amplitude. Waveform b is an FFT waveform of waveform a. The waveform b is represented by a frequency on the horizontal axis and a power spectrum on the vertical axis. Each value of FIGS. 4A to 4D is as shown in Table 1 and Table 2 below.

FIG. 4A shows a waveform when the stepping motor 205 is normally driven alone.
The waveform a has an amplitude v1 = 1.2 [V]. The waveform b indicates that the frequency f1 is the driving frequency of the stepping motor 205 and a frequency component that is an integral multiple of the frequency f1 is generated.

FIG. 4B shows a waveform when the stepping motor 205 is driven alone to step out.
At the time of step-out, the waveform a has an amplitude v2 = 2.4 [V], and the amplitude of the waveform a becomes larger than that during normal driving. Moreover, it can confirm that the peak generate | occur | produces periodically.
In the waveform b, in addition to the frequency f1, the frequency f2 and a frequency component that is an integral multiple of the frequency f2 are generated by the vibration of the stepping motor 205 due to the step-out. Therefore, it is possible to determine the step out of the stepping motor 205 by analyzing the waveform b and determining whether the magnitude of the power spectrum of the frequency component generated only during the step out exceeds the threshold. In FIG. 4B, the reference value of the power spectrum is about −30 [dBV], and the power spectrum of the peak of the frequency f2 that occurs only at the time of step-out is −10 [dBV] to −14 [dBV]. Therefore, if the threshold value is set to −20 [dBV], it is possible to determine the step-out.

  FIG. 4C shows a vibration waveform by the vibration sensor 206 when all the motors in the image forming apparatus 1 are driven. Since a plurality of motors are driven, the amplitude v3 of the waveform a is 1.8 [V], which is larger than the amplitude v1 in FIG. Since the vibration sensor 206 is disposed in the vicinity of the stepping motor 205, the waveform b represents that a frequency component that is an integral multiple of the frequency f1 is generated, as in FIG. However, in FIG. 4C, since the motor other than the stepping motor 205 is also driven, the frequency component and the reference value as seen in the frequency f3 are increased.

FIG. 4D shows a vibration waveform by the vibration sensor 206 when all the motors in the image forming apparatus 1 are driven and only the stepping motor 205 is stepped out. Since the amplitude v4 = 2.1 [V] of the waveform a is close to the amplitude v3 of FIG. 4C, it can be detected from the amplitude of the waveform a that the stepping motor 205 is out of step. Can not.
In the waveform b, as in FIG. 4B, a frequency component that is an integral multiple of the frequency f2 observed during the step-out occurs. In FIG. 4D, the reference value of the power spectrum is about −20 [dBV], and the power spectrum of the peak of the frequency f2 generated only at the time of step-out is −10 [dBV] to −14 [dBV]. Therefore, if the threshold value for determining an abnormality is set to −20 [dBV], the reference value may be erroneously determined to be abnormal, and if it is set to −10 [dBV], it may not be detected. That is, compared with the waveform b in FIG. 4B, since the difference between the peak and the reference value is small, there is no clear difference in the power spectrum with respect to the threshold value, making it difficult to determine the step-out.

  Thus, the vibration waveform is different between normal operation and abnormal operation. Therefore, whether the stepping motor 205 is normal or abnormal can be determined from the vibration waveform. Further, according to FIG. 4, in order to reliably determine the step-out of the stepping motor 205, it is better to drive only the stepping motor 205 to be determined than to drive all the motors. 4B is an example of information for specifying the cause of the abnormal phenomenon from the physical values such as vibrations and sounds detected after the occurrence of the abnormality, such as the peak value of the power spectrum in FIG. It becomes. In addition, in ROM 203, the peak value of the power spectrum shown in FIG. 4A and the quantitative data such as the frequency and the threshold at that time are specified in order to identify the cause of the abnormal phenomenon from the physical quantities such as vibration and sound detected after the occurrence of the abnormality. It may be stored as information. That is, the ROM 203 stores at least one quantitative data during normal operation and abnormal operation when the stepping motor 205 operates alone.

  FIG. 5 is a flowchart of processing for identifying an abnormal part. Here, a case where an operation abnormality has occurred in the stepping motor 205 will be described.

  When the image forming process is started, the stepping motor 205 starts to be driven by an instruction from the CPU 201 (S501). The CPU 201 has a timer function and starts measuring time t from the start of driving. The printing paper P is conveyed from the cassette 17 by driving the stepping motor 205. When the printing paper P reaches the detection position of the conveyance sensor 218 through the conveyance path, the conveyance sensor 218 detects this (S502: Y). The fact that the conveyance sensor 218 detects the printing paper P means that the conveyance operation of the printing paper P is normally performed, and thus the CPU 201 determines that the conveyance operation is normally performed. (S504). In this case, the CPU 201 notifies the controller 217 that a normal operation is being performed (S510).

When the conveyance sensor 218 does not detect the printing paper P, the CPU 201 determines whether a time T1 (for example, 2 seconds) that is a criterion for determining that the conveyance of the printing paper P is abnormal has elapsed. (S503). If the time T1 has not elapsed, the detection by the transport sensor 218 is again waited (S503: N, S502). When the time T1 has elapsed, the CPU 201 determines that an abnormal phenomenon has occurred in the printing paper P conveyance system. Then, the operation of the motors in the image forming apparatus 1 other than the stepping motor 205 related to the abnormal phenomenon is stopped, and the timer time t is reset (S503: Y, S505).
The determination of the motor related to the abnormal phenomenon is made based on information representing the relationship of the cooperating parts stored in the ROM 203. In the above example, for the abnormal phenomenon that the detection of the printing paper P by the transport sensor 218 is not performed in time, the stepping motor 205 related to this is determined as a motor related to the abnormal phenomenon.

  While only the stepping motor 205 related to the abnormal phenomenon is driven, the CPU 201 acquires vibration data detected by the vibration sensor 206 for a predetermined time T2 (for example, 10 milliseconds) (S506, S507). CPU201 which acquired vibration data for time T2 stops a drive of stepping motor 205 (S507: Y, S508). The drive stop is performed, for example, when the abnormality diagnosis unit 305 instructs the motor drive module 303 via the abnormality identification unit 307.

  The CPU 201 performs, for example, FFT analysis on the acquired vibration data, and determines whether or not the stepping motor 205 is out of step from the value of the power spectrum and the frequency at the time of peak generation (S509). As described with reference to FIG. 4, whether or not the stepping motor 205 is out of step can be determined from the peak frequency of the power spectrum. This determination can also be made based on information stored in the ROM 203 for specifying the cause of the abnormal phenomenon from the physical quantity.

  The CPU 201 notifies the analysis result of the vibration data to the controller 217 (S510). The controller 217 displays the content and cause of the abnormal phenomenon on the display means of the operation unit 222 based on the notification content, and notifies the user.

In this example, the detection of the step-out of the stepping motor 205 has been described. In addition to this, if vibration data at the time of occurrence of an abnormality such as a rotation abnormality of the paper feed roller 18 or the registration roller 19 is acquired in S506 in advance, The cause of the abnormality can be specified in detail.
In addition, the configuration using the vibration sensor 206 for specifying the abnormal part has been described, but the abnormal part can be specified in the same sequence by using a microphone instead of the vibration sensor 206. In this case, sound is used as a physical quantity detected instead of vibration data, and an abnormal part is specified by its magnitude, frequency component, and the like. Since the sound also changes during normal operation and abnormal operation, it is effective in determining the occurrence of abnormality.

[Second Embodiment]
In the first embodiment, the example in which the step-out of the stepping motor 205 is detected has been described. However, the step-out may be a sudden factor. In this case, the abnormality may be resolved by feeding paper again. In the second embodiment, processing in such a case will be described.
The image forming apparatus of the second embodiment has the same configuration as the image forming apparatus 1 of the first embodiment.

  6a and 6b are flowcharts of processing for identifying an abnormal part according to the second embodiment. Compared to the first embodiment, the processing of S601 to S609 corresponds to the processing of S501 to S509 (FIG. 5) of the first embodiment, and has the same processing contents. Therefore, the description of the processing of S601 to S609 is omitted.

  If it is determined in step S609 that the stepping motor 205 has not stepped out, the CPU 201 notifies the controller 217 that an abnormality other than stepping out has occurred (S610: N, S611). The controller 217 displays the content and cause of the abnormal phenomenon on the display means of the operation unit 222 based on the notification content, and notifies the user.

  If it is determined in step S609 that the stepping motor 205 is out of step, the CPU 201 resets the timer time t by re-driving the stepping motor 205 in order to feed paper again (S610: Y, S612). ). For example, after the abnormality diagnosis unit 305 determines the step out, the motor driving module 303 is instructed to redrive the stepping motor 205 via the abnormality identification unit 307. Since the stepping motor 205 may step out due to noise on the input signal or sudden overload, it may be driven normally by re-driving.

If the conveyance sensor 218 detects the printing paper P within the time T1 after re-driving the stepping motor 205, the CPU 201 determines that the operation is normally performed (S613: Y, S615). When the conveyance sensor 218 does not detect the printing paper P within the time T1, the CPU 201 determines that the stepping motor 205 has stepped out and notifies the controller 217 (S614: N, S615: Y, S616). ). The controller 217 displays the content and cause of the abnormal phenomenon on the display means of the operation unit 222 based on the notification content, and notifies the user.
Thus, when returning to normal operation by re-operation, it is not necessary to deal with an abnormal phenomenon, so the burden on the user is reduced.

[Third Embodiment]
In the third embodiment, an abnormal part detection process for an abnormal phenomenon caused by part destruction will be described. Here, a case where the components of the fixing device 16 are destroyed will be described as an example.
FIG. 7 is a cross-sectional view of the fixing device 16. As described in the first embodiment, the fixing device 16 includes the fixing film 16a and the pressure roller 16b.

The fixing film 16a is a thin and flexible endless belt-like (cylindrical) heating rotating body with a thickness of 20 to 150 [μm], and a release layer is formed on the surface layer. The fixing film 16a is loosely fitted to the film guide member (stay) 161 having a semicircular arc shape in cross section with a margin in the circumferential length. The fixing film 16a has a reduced heat capacity and improved quick start performance. A heater for heating (hereinafter simply referred to as “heater”) 162 is disposed and fixedly supported in the central portion on the lower surface side of the film guide member 161 along the longitudinal direction.
The pressure roller 16b is a pressure rotating body having a silicone rubber layer (elastic layer) and a PFA tube layer as a release layer on a core metal such as iron or aluminum. The pressure roller 16b forms a nip portion 31 having a width corresponding to the width of the printing paper P with the heater 162 via the fixing film 16a.

The pressure roller 16b is driven by a brushless motor 219. The fixing film 16a rotates by receiving the rotational drive of the pressure roller 16b by the frictional force in the nip portion 31. The fixing film 16 a slides in close contact with the heater 162 surface at the nip portion 31.
When the printing paper P with the toner 165 transferred to the nip portion 31 is conveyed, the toner 165 is fixed to the printing paper P by the heat from the heater 162 and the pressure from the pressure roller 16b. The printing paper P is conveyed to the outer paper discharge roller 21 side by the rotation of the fixing film 16a and the pressure roller 16b.

When the flexible fixing film 16 a having such an elastic layer is used for the fixing device 16, the fixing film 16 a and the pressure roller 16 b are determined depending on the accuracy of components and the mounting accuracy of the fixing device 16 to the image forming apparatus 1. It is difficult to keep them completely parallel. As a result, as shown in FIG. 8, a crossing angle α is generated between the pressure roller 16b and the fixing film 16a, and the fixing film 16a that is driven to rotate by the rotation of the pressure roller 16b is either left or right in the longitudinal direction. An approaching force is generated.
In this case, the end of the fixing film 16a is pressed against either one of the film position regulating members 164 installed at both ends of the pressure roller 16b, and the deviation of the fixing film 16a is regulated. As a result, the fixing film 16a rotates without departing from the regulated position. However, internal stress and bending stress are generated at the end of the fixing film 16a pressed against the film position regulating member 164.
Further, the curvature of the fixing film 16a changes during the rotation process, so that the fixing film 16a is repeatedly bent. As a result, repeated stress is generated inside the fixing film 16a, and fatigue failure may occur due to long-term use. In particular, when the fixing film 16a is used in the color image forming apparatus 1, the shift force applied to the end portion of the fixing film 16a due to the increase in the pressure and the frictional force is 9.8 [N] (1 [kgf]). ) May be more.

  For this reason, when the torque of the pressure roller 16b increases, rotation abnormality of the brushless motor 219 occurs. When rotation abnormality occurs, the fixing film 16a generates noise due to friction between the fixing film 16a and the film position regulating member 164.

  FIG. 9 is a diagram illustrating a connection relationship between each functional block configured in the CPU 201, the brushless motor 219, and the vibration sensor 220. Each function of the CPU 201 forms an abnormality detection device realized by the CPU 201 reading a program from the ROM 203 and executing it.

The operation of the brushless motor 219 is controlled by the motor drive module 308 of the CPU 201, and outputs a rectangular wave FG signal representing the rotation speed.
The abnormality detection unit 309 detects the rotational speed of the brushless motor 219 based on the FG signal, and determines that an abnormal phenomenon has occurred if the detected rotational speed is not within a predetermined range. When the abnormality detection unit 309 determines that an abnormal phenomenon has occurred, the abnormality specifying unit 307 specifies a drive component (first component) that is related to a rotational speed abnormality of the brushless motor 219 (target component). In the third embodiment, the pressure roller 16b and the fixing film 16a are the specified drive components. The identification of the component is performed based on information representing the relationship of the cooperative components stored in the ROM 203.

The vibration sensor 220 is a sensor that detects vibration in the vicinity of the fixing device 16. Vibration data representing the detected vibration is analyzed by the vibration detection unit 302. The abnormality diagnosis unit 305 stops the operation of other parts (second part) other than the part related to the occurrence of the abnormal phenomenon specified by the abnormality specifying part 307 (the fixing device 16 in this example), and vibrates during the stop. An abnormal part is identified from the result of detection and analysis by the detection unit 302 for a predetermined time.
The vibration detection unit 302 and the abnormality diagnosis unit 305 perform analysis and identification of factors based on information for identifying the cause of the abnormal phenomenon stored in the ROM 203, for example. The identified vibration factor is displayed on the display means of the operation unit 222 via the controller 217, thereby notifying the user.
The controller 217 receives the result of the abnormality diagnosis unit 305, and displays the result on the display unit of the operation unit 222 if it is abnormal.

  FIG. 10 is a flowchart of processing for identifying an abnormal part according to the third embodiment.

  When the image forming process is started, the brushless motor 219 starts to be driven together with the motors 207 for forming an image in accordance with an instruction from the CPU 201 (S1001). The CPU 201 starts measuring time t from the start of driving by the timer function.

  The CPU 201 detects the rotation speed of the brushless motor 219 based on the FG signal sent from the brushless motor 219. When the rotational speed of the brushless motor 219 deviates from the predetermined range, the CPU 201 resets the time t when deviating and measures the time deviating from the predetermined range. When the time outside the predetermined range is equal to or longer than the predetermined time, the CPU 201 determines that an abnormal phenomenon has occurred in the fixing device 16 (S1002: N, S1003: Y). For example, when the predetermined range of the rotation speed is 3000 [rpm] ± 3% and the predetermined time is 500 milliseconds, the CPU 201 drives the brushless motor 219 if it detects a rotation speed outside the range for 500 milliseconds. It is determined that an abnormal phenomenon has occurred in the fixing device 16. Even if the rotation speed is within a predetermined range (S1002: Y) or outside the predetermined range, if the rotation speed is less than a predetermined time (500 milliseconds) (S1002: N, S1003: N), the CPU 201 performs normal operation. It is determined that it is being performed (S1004).

  When the CPU 201 determines that an abnormal phenomenon has occurred in the fixing device 16, the CPU 201 stops the operation of the motors in the image forming apparatus 1 other than the brushless motor 219 related to the abnormal phenomenon of the fixing device 16, and the timer time t Is reset (S1005). The CPU 201 determines the motor related to the abnormality based on the stored contents of the ROM 203 as in the first embodiment.

  While only the brushless motor 219 related to the abnormality is driven, the CPU 201 acquires vibration data detected by the vibration sensor 206 for a predetermined time T2 (for example, 100 milliseconds) (S1006, S1007). CPU201 which acquired vibration data stops a drive of brushless motor 219 (S1008).

The CPU 201 performs, for example, FFT analysis on the acquired vibration data, and determines whether or not abnormal vibration has occurred due to the deviation of the fixing film 16a from the value of the power spectrum and the frequency at the time of peak generation (S1009). The frequency at which the peak of the power spectrum occurs due to the abnormal vibration due to the fixing film 16a is stored in the ROM 203 in advance. The CPU 201 determines from the power spectrum obtained from the vibration data and the stored contents of the ROM whether the abnormal phenomenon is caused by abnormal vibration due to the offset of the fixing film 16a. The CPU 201 notifies the analysis result to the controller 217 (S1010). If an abnormal phenomenon due to the offset of the fixing film 16a has occurred, the controller 217 displays the content and cause of the abnormal phenomenon on the display means of the operation unit 222 to notify the user.
As described above, it is possible to identify the cause of an abnormal phenomenon due to the destruction of parts.

  DESCRIPTION OF SYMBOLS 1 ... Image forming apparatus 201 ... CPU, 203 ... ROM, 204 ... RAM, 217 ... Controller, 222 ... Operation part, 302 ... Vibration detection part, 303 ... Motor drive module, 304, 309 ... Abnormality detection part, 305 ... Abnormality Diagnosis unit, 307, abnormality identification unit, 205, stepping motor, 206, 220, vibration sensor, 218, conveyance sensor, 219, brushless motor, 16, fixing device, 16a, fixing film, 16b, pressure roller.

Claims (7)

An image forming apparatus for forming an image on a recording medium, comprising: a target part; a first part that cooperates with the target part; and a second part.
Detecting means for detecting an abnormality related to processing performed by the target component and the first component;
Physical quantity detection means for detecting a predetermined physical quantity;
When the abnormality is detected, the operation of the second part is stopped, and the presence or absence of the operation abnormality of the first part is diagnosed from the physical quantity detected by the detection means while the operation of the second part is stopped. A diagnostic means for
Image forming apparatus. The first part and the second part are motors;
The target part is a roller driven by the first part, and conveys a recording medium on which the image is formed,
The predetermined physical quantity is vibration,
The image forming apparatus according to claim 1. After the diagnosis means diagnoses that the first component has an operation abnormality, when the abnormal phenomenon is not resolved when the first component and the second component are operated again, the first component is abnormal. Characterized as being a part,
The image forming apparatus according to claim 1. The physical quantity detection means is quantitative data representing any change in vibration and sound generated in the first part and the second part,
The image forming apparatus according to claim 2. A storage means for storing at least one quantitative data during normal operation and during abnormal operation when the first component operates alone;
The diagnostic means diagnoses the presence or absence of an abnormal operation of the first component by comparing the physical quantity detected by the physical quantity detection means with the quantitative data stored in the storage means,
The image forming apparatus according to claim 1. The first part is a stepping motor;
The abnormal operation of the first component is step-out,
After the diagnosis means determines that the first part has stepped out, the first part has stepped out if the abnormality is not resolved when the first part is restarted. When the abnormality is resolved when the first part is restarted after determining that the first part is out of step, the first part is out of step. It is characterized by not notifying,
The image forming apparatus according to claim 2. The first part is a motor;
The detection means detects an abnormality in the rotation speed of the motor,
The image forming apparatus according to claim 1, wherein the predetermined physical quantity is vibration.