JP6922433B2 - How to support image forming equipment and its maintenance work - Google Patents

Description

The present invention relates to an image forming apparatus and a method for supporting maintenance work thereof.

An image forming apparatus such as a printer, a copier, or a multifunction device takes out sheet-shaped paper from a paper storage unit, conveys it, and prints an image on the conveyed paper at a predetermined position. Rollers are arranged in the transport path inside the image forming apparatus at intervals shorter than the length of the paper, and the image forming apparatus rotates the rollers so that the paper passes through each position on the transport path at a predetermined timing. Control the drive.

A brushless motor is used as a drive source for rotating the rollers. According to the vector control that controls the alternating current flowing through the winding (coil) of the brushless motor as a vector component of the dq coordinate system, the brushless motor can be rotated efficiently and smoothly.

A clutch is often used to turn the rotary drive of the rollers on and off. By interposing a clutch that interrupts the transmission of the rotational driving force between the roller and the motor that is the driving source thereof, the roller can be stopped while the motor is rotating. The clutch is used, for example, when one motor is desired to be used as a drive source for a plurality of rollers whose rotation timings are different from each other.

The clutch has a response delay to the control signal. That is, when switching the roller and the motor from the released state to the connected state, it takes, for example, several ms from the command of the switching to the completion of the connection. Also, when switching from the connected state to the released state, it takes about the same release time.

As prior arts for predicting the replacement time of parts of an image forming apparatus, there are the techniques described in Patent Documents 1 and 2.

In Patent Document 1, in an electrophotographic image forming apparatus, the load current of a motor that rotationally drives a photoconductor is detected as a drive torque, and the degree of deterioration of a blade that cleans the surface of the photoconductor is a detection value of the drive torque. It is described that the judgment is made based on.

In Patent Document 2, as an improvement of the technique of Patent Document 1, the driving torques of the state where the developer is present on the surface of the photoconductor and the state where the developer is not present are detected, and the difference between these detected values (torque difference). It is stated that the blade replacement time is predicted based on.

On the other hand, there is a technique described in Patent Document 3 as a prior art for reducing the variation in the image formation position on the paper due to the variation in the response delay of the clutch. In Patent Document 3, a sensor for detecting the rotation of the roller is provided on the roller, the time from when the clutch is turned on until the roller starts rotating is measured as a connection time, and the clutch on timing is corrected based on the result. It is described that the paper transport accuracy is made uniform.

Japanese Unexamined Patent Publication No. 11-352852 Japanese Unexamined Patent Publication No. 2005-202099 Japanese Unexamined Patent Publication No. 2000-281235

In the image forming apparatus, a jam may occur in which the paper is stagnant in the transport path. Conventionally, there has been a problem that maintenance work for identifying the true cause of jam and preventing recurrence may be troublesome, especially when the reproducibility is low.

One of the causes of jams with low reproducibility is considered to be a shift in the timing of paper transfer due to a clutch malfunction or a slip on the roller surface. However, the service person knows that the clutch is malfunctioning when the clutch does not operate or is clearly slow, but the operating characteristics such as the engagement time or release time being longer or shorter than the appropriate value. It was not possible to easily know the subtle changes over time. It was also not easy to judge the degree of quality of the surface condition of the rollers.

It is difficult to detect the drive torque of the motor with the accuracy required for determining the quality of the operating characteristics of the clutch by the method of detecting the load current of the motor as the drive torque as in the techniques of Patent Documents 1 and 2 described above. That is, the load current of the motor includes a loss amount generated inside the motor, and this loss amount changes according to the rotation speed. Therefore, it is necessary to detect the fluctuation of the rotation speed due to the engagement and disengagement of the clutch and perform the loss correction according to the rotation speed.

Further, in the case of the above-mentioned technique of Patent Document 3, an expensive sensor capable of detecting the rotation of the roller with high accuracy is required. By providing the sensor, the number of parts increases and the cost increases. It is also necessary to secure a space for mounting the sensor.

The present invention has been made in view of the above problems, and an object of the present invention is to provide an image forming apparatus capable of increasing the efficiency of maintenance work for preventing the occurrence of jam, and a method for supporting maintenance work. ..

The image forming apparatus according to the embodiment of the present invention is an image forming apparatus that forms an image on a sheet, and comprises a roller for transporting the sheet, a motor for rotationally driving the roller, and a vector of the motor. A motor control unit to be controlled, a clutch that transmits the rotational driving force of the motor to the roller, and a detection value of a current that flows through the motor to generate rotational torque are acquired from the motor control unit and are based on the detected values. It has a measuring unit for measuring the engagement time of the clutch and a support processing unit for performing support processing for supporting the maintenance work according to the measured value of the engagement time.

A method of supporting maintenance work according to an embodiment of the present invention is a method of supporting maintenance work of an image forming apparatus having a clutch for transmitting a rotational driving force of a motor to a roller that conveys a sheet and vector-controlling the motor. The clutch coupling time is measured by the image forming apparatus based on the detected value of the current flowing through the motor and generating the rotational torque acquired in the vector control, and the image forming apparatus is said to be said. By comparing the measured value of the connection time with a plurality of threshold values, it is determined whether or not the operating characteristics of at least the clutch among the parts related to the transfer of the sheet are good or bad, and the determination result is notified. ..

According to the present invention, it is possible to improve the efficiency of maintenance work for preventing the occurrence of jam.

It is a figure which shows the outline of the structure of the image forming apparatus which concerns on one Embodiment of this invention. It is a figure which shows typically the example of the structure of the mechanism which transmits the rotational driving force of a motor to a roller. It is a figure which shows the dq axis model of a motor. It is a figure which shows the functional structure of the motor control device. It is a figure which shows the reaction delay of a clutch. It is a figure which shows the functional structure of the main part of the upper control part. It is a figure which shows typically the change of the rotational torque of a motor at the time of engaging a clutch. It is a figure which shows typically the change of the rotational torque of a motor when the clutch is released. It is a figure which shows the example of discriminating the coupling operation characteristic of a clutch. It is a figure which shows the example of discriminating the release operation characteristic of a clutch. It is a figure which shows the example of the processing flow in maintenance inspection by a service person. It is a figure which shows the flow of the state monitoring process in an image forming apparatus.

FIG. 1 shows an outline of the configuration of the image forming apparatus 1 according to the embodiment of the present invention. The image forming apparatus 1 is a color printer provided with an electrophotographic printer engine 10.

The printer engine 10 has four imaging stations 11y, 11m, 11c, 11k. Each of the imaging stations 11y to 11k has a tubular photoconductor, a charged charger, a developing device, a cleaner, a light source for exposure, and the like.

In the color printing mode, the four imaging stations 11y to 11k form four color toner images of Y (yellow), M (magenta), C (cyan), and K (black) in parallel. The four-color toner image is primarily transferred to the intermediate transfer belt 16. Then, when facing the secondary transfer roller 15, the secondary transfer is performed on the sheet (recording paper) 9 which is pulled out from the paper cassette 12 by the paper feed roller 21 and conveyed via the resist roller pair 14. After the secondary transfer, the paper is sent out to the upper output tray 18 through the inside of the fixing device 17. When passing through the fuser 17, the toner image is fixed to the sheet 9 by heating and pressurizing.

The resist roller pair 14 corrects the skew of the sheet 9 and sends the sheet 9 to the secondary transfer position. That is, when the sheet 9 conveyed from the paper cassette 12 arrives at the nip portion of the resist roller pair 14, the resist roller pair 14 is stopped. The sheet 9 being conveyed bends when it comes into contact with the nip portion. At the timing when the sheet 9 is appropriately bent and its tip edge is parallel to the roller axis, the resist roller pair 14 rotates to convey the sheet 9.

The motor 3 that rotationally drives the resist roller pair 14 is also used, for example, as a drive source for the photoconductor and the developing device of the imaging station 11k. In order to turn on / off the rotation of the resist roller pair 14 independently of the rotation control of the imaging station 11k, the rotational driving force of the motor 3 is transmitted to the resist roller pair 14 via the clutch 5.

Seat sensors 19A and 19B that output signals indicating the presence or absence of the seat 9 are provided in the vicinity of each of the upstream side and the downstream side of the resist roller pair 14. The signal from the seat sensor 19A on the upstream side is used to adjust the timing at which the rotation of the resist roller pair 14 is started. The signal from the sheet sensor 19B on the downstream side is used to adjust the timing at which the rotation of the resist roller pair 14 is temporarily stopped when the sheet 9 is made to stand by before the secondary transfer position.

FIG. 2 schematically shows an example of the configuration of a mechanism for transmitting the rotational driving force of the motor 3 to the roller 14A. FIG. 2A shows the overall configuration of the mechanism, and FIG. 2B shows the engaged state of the clutch 5.

The clutch 5 is connected to one roller 14A of the resist roller pair 14. The other roller 14B is driven by the roller 14A to rotate.

The clutch 5 is an electromagnetic friction clutch, and has a gear portion (driving portion) 5A that can move in the rotation axis direction of the roller 14A and a driven portion 5B that rotates integrally with the roller 14A. The rotational driving force is transmitted from the motor 3 to the gear portion 5A via the gears 4b, 4f, 4g, 4i, and 4j in this order. The gear portion 5A slightly moves in the direction of the rotation axis in a state of being meshed with the gear 4j. In the released state, the gear portion 5A is separated from the driven portion 5B. When a magnetic force is applied, as shown in FIG. 2B, the gear portion 5A moves and comes into close contact with the driven portion 5B, and the clutch 5 is in a connected state.

Gears 4a and 4c are fitted into the rotating shaft 3S of the motor 3 together with the gear 4b. The gear 4a meshes with the gear 4d for transmitting the rotational driving force to the photoconductor of the imaging station 11k, and the gear 4c meshes with the gear 4e for transmitting the rotational driving force to the developing device. That is, in addition to the load torque of the resist roller pair 14, the load torque of the imaging station 11k is applied to the motor 3.

The rotation of the motor 3 is switched according to the process speed. The process speed is an image forming condition that defines the rotation speed of the photoconductor, the transport speed of the sheet 9, and the like. For example, when thick paper is used as the sheet 9, the process speed is set to be slower than when plain paper is used. That is, the rotation speed of the motor 3 is reduced. As a result, the time for the sheet 9 to pass through the fuser 17 becomes longer, so that the sheet 9 can be sufficiently heated to improve the fixability of the toner image.

The motor 3 is a DC brushless motor, for example, a sensorless type permanent magnet synchronous motor (PMSM). The motor 3 includes a stator as an armature for generating a rotating magnetic field and a rotor using a permanent magnet. The stator has U-phase, V-phase, and W-phase cores arranged at 120 degree intervals, and three Y-connected windings (coils) 33, 34, 35 (see FIG. 4). A rotating magnetic field is generated by passing a three-phase alternating current of U-phase, V-phase, and W-phase through windings 33 to 35 to excite the core in order. The rotor rotates in synchronization with this rotating magnetic field.

In order to rotate the motor 3 efficiently and smoothly, vector control (sensorless vector control) is performed on the motor 3 to estimate the rotation speed and the magnetic pole position using a control model based on the dq coordinate system. ..

FIG. 3 shows a dq-axis model of the motor 3. In the vector control of the motor 3, the three-phase alternating current flowing through the windings 33 to 35 of the motor 3 is converted into a direct current flowing through the two-phase windings rotating in synchronization with the permanent magnet which is a rotor. To simplify.

The magnetic flux direction (direction of the north pole) of the permanent magnet is defined as the d-axis, and the direction advanced by π / 2 [rad] (90 °) in electrical angle from the d-axis is defined as the q-axis. The d-axis and the q-axis are model axes. With reference to the U-phase winding 33, the lead angle of the d-axis with respect to this is defined as θ. This angle θ indicates the angular position (magnetic pole position) of the magnetic pole with respect to the winding 33 of the U phase. The dq coordinate system is located at a position advanced by an angle θ with respect to the U-phase winding 33.

Since the motor 3 does not have a position sensor for detecting the angular position (pole position) of the rotor, the magnetic pole position (that is, the angle θ) of the rotor 32 is estimated, and the estimated angle θm, which is the estimated angle θ, is calculated. It is used to control the rotation of the rotor.

Of the currents flowing through the windings 33 to 35, the q-axis component flowing in the q-axis direction is converted into torque (rotational torque) in the direction of forward rotation or reverse rotation of the motor 3 according to the induced voltage constant. On the other hand, the d-axis component (d-axis current) flowing in the d-axis direction is not converted into torque and is consumed as heat in the windings 33 to 35.

FIG. 4 shows the functional configuration of the motor control device 21. The motor 3 is driven and controlled by the motor control device 21. The motor control device 21 includes a vector control unit 25, a motor drive unit 26, a current detection unit 27, and the like.

The motor drive unit 26 is an inverter circuit for driving a rotor by passing an electric current through the windings 33 to 35 of the motor 3. The motor drive unit 26 turns on and off a plurality of transistors according to the control signals U +, U−, V +, V−, W +, W− from the vector control unit 25, thereby winding 33 to 35 from the DC power supply line 260 to the ground line. Control the current flowing through. Specifically, the current Iu flowing through the winding 33 is controlled according to the control signals U +, U−, the current Iv flowing through the winding 34 is controlled according to the control signals V +, V−, and the current Iw flowing through the winding 35 is controlled according to the control signals W +, W−. Control according to.

The current detection unit 27 detects the currents Iu and Iv flowing through the windings 33 and 34. Since Iu + Iv + Iw = 0, the current Iw can be obtained by calculation from the detected values of the currents Iu and Iv. It may have a W-phase current detection unit.

The current detection unit 27 amplifies the voltage drop due to the shunt resistor inserted in the flow path of the currents Iu and Iv, performs A / D conversion, and outputs the detected values of the currents Iu and Iv. That is, the two-shunt method is detected. The resistance value of the shunt resistor is as small as 1/10 Ω.

A speed command S1 indicating a target speed (speed command value) ω * is input to the vector control unit 25 from the upper control unit 20. The upper control unit 20 is a controller that is in charge of overall control of the image forming apparatus 1, and rotates or rotates the motor 3 when warming up the image forming apparatus 1, executing a print job, shifting to a power saving mode, or the like. Command to stop. Further, the upper control unit 20 commands the clutch drive unit 51 to turn on / off the clutch 5 by the clutch control signal S5.

The vector control unit 25 includes a speed control unit 41, a current control unit 42, an output coordinate conversion unit 43, a PWM conversion unit 44, an input coordinate conversion unit 45, and a speed / position estimation unit 46.

The speed control unit 41 performs a calculation for proportional integration control (PI control) that brings the difference between the target speed ω * from the upper control unit 20 and the estimated speed ωm from the speed / position estimation unit 46 close to zero, and d. Determine the current command values Id * and Iq * in the −q coordinate system. The estimated speed ωm is input periodically. The speed control unit 41 determines the current command values Id * and Iq * each time the estimated speed ωm is input.

The current control unit 42 has the difference between the current command value Id * and the estimated current value (d-axis current value) Id from the input coordinate conversion unit 45, and the estimated current from the input coordinate conversion unit 45 like the current command value Iq *. An operation for proportional integration control that brings the difference from the value (q-axis current value) Iq close to zero is performed. Then, the voltage command values Vd * and Vq * in the dq coordinate system are determined.

The output coordinate conversion unit 43 sets the voltage command values Vd *, Vq * to the U-phase, V-phase, and W-phase voltage command values Vu *, Vv *, based on the estimated angle θm from the velocity / position estimation unit 46. Convert to Vw *. That is, the voltage is converted from two phases to three phases.

The PWM conversion unit 44 generates a pattern of control signals U +, U−, V +, V−, W +, W− based on the voltage command values Vu *, Vv *, Vw *, and outputs the pattern to the motor drive unit 26. The control signals U +, U−, V +, V−, W +, and W− are signals for controlling the frequency and amplitude of the three-phase AC power supplied to the motor 3 by pulse width modulation (PWM). ..

The input coordinate conversion unit 45 calculates the value of the W phase current Iw from each value of the U phase current Iu and the V phase current Iv detected by the current detection unit 27. Then, based on the estimated angle θm from the velocity / position estimation unit 56 and the values of the three-phase currents Iu, Iv, and Iw, the d-axis current values Id and q-axis, which are the estimated current values of the d−q-axis coordinate system, are used. Calculate the current value Iq. That is, the current is converted from three phases to two phases. The q-axis current value Iq is an example of a detected value of a current that flows through the motor 3 and generates a rotational torque.

The speed / position estimation unit 46 estimates the speed according to a so-called voltage-current equation based on the estimated current values (Id, Iq) from the input coordinate conversion unit 45 and the voltage command values Vd *, Vq * from the current control unit 52. Obtain the value ωm and the estimated angle θm. The obtained speed estimation value ωm is input to the speed control unit 41. The obtained estimated angle θm is input to the output coordinate conversion unit 43 and the input coordinate conversion unit 45.

By the way, the image forming apparatus 1 has a function of providing a service person with information useful for preventing jams on the sheet 9. Hereinafter, the configuration and operation of the image forming apparatus 1 will be described with a focus on this function.

FIG. 5 shows the reaction delay of the clutch 5.

The clutch 5 is turned on and off while the motor 3 is rotating at a speed corresponding to the process speed. Switching from the OFF level to the ON level of the clutch control signal S5 corresponds to a connection command for the clutch 5, and switching from the ON level to the OFF level bell corresponds to a release command.

When the engagement command or the release command is issued, the state transition of the clutch 5 (movement of the gear portion 5A) starts substantially immediately. Then, when the connection time Ta or the release time Tb elapses, the state transition is completed. The coupling time (engagement time) Ta is the time required for the clutch operation (coupling) from the start of the state transition to the steady transmission in the state transition from the released state in which the rotational driving force is not transmitted. The release time Tb is the time required for the clutch operation (release) from the engaged state in which transmission is steady to the released state.

The connection time Ta and the release time Tb change slightly depending on the individual difference and the condition of the clutch 5. Therefore, by accurately measuring (measuring) at least one of the connection time Ta and the release time Tb, it is possible to determine whether the condition of the clutch 5 is good or bad and to detect a sign of a change in the condition. Then, measures such as cleaning, repair, and replacement can be carried out.

Therefore, the image forming apparatus 1 measures the connection time Ta and the release time Tb based on the q-axis current value Iq obtained by the vector control unit 25. The q-axis current value Iq keeps the rotation speed of the motor 3 at the target speed (ω *) according to the change of the load torque applied to the motor 3 in the current (motor current) flowing from the DC power supply line 260 to the motor 3. Indicates the magnitude of the q-axis current component that increases or decreases the rotational torque. According to the q-axis current component, which is a component obtained by removing the d-axis current component from the motor current, it is possible to accurately detect the change in the load torque of the motor 3 as compared with the case of using the motor current including the d-axis current component. Since the load torque changes abruptly at the moment when the engagement or release is completed, the time from the switching of the clutch control signal S5 to the abrupt change in the load torque may be measured as the connection time Ta or the release time Tb.

In the measurement of the connection time Ta and the release time Tb, it is not always necessary to obtain the measured value in units of time, and other units or unknown values or data related thereto may be used.

FIG. 6 shows the functional configuration of the main part of the upper control unit 20. FIG. 7 schematically shows a change in the rotational torque Mt of the motor 3 when the clutch 5 is engaged, and FIG. 8 schematically shows a change in the rotational torque Mt of the motor 3 when the clutch 5 is released. Further, FIG. 9 shows an example of determining the engagement operation characteristic of the clutch 5, and FIG. 10 shows an example of determining the release operation characteristic of the clutch 5.

In FIG. 6, the upper control unit 20 includes a process control unit 201, a transfer control unit 202, a measurement unit 203, a support processing unit 204, and the like. These functions are realized by the hardware configuration of the upper control unit 20 including the CPU (Central Processing Unit) and its peripheral devices, and by executing the control program by the CPU.

The process control unit 201 controls the progress of the electrophotographic process by the printer engine 10. The process control unit 201 gives the vector control unit 25 a target speed ω * according to the process speed.

The transport control unit 202 controls the transport of the seat 9. The transport control unit 202 monitors the progress of transport based on signals from the seat sensors 19A, 19B, etc., and commands the clutch drive unit 51 to connect / release the clutch 5 at an appropriate timing.

The measuring unit 203 acquires the q-axis current value (estimated current value) Id, which is the detected value of the q-axis current that flows through the motor 3 to generate the rotational torque Mt, from the vector control unit 25. Then, the coupling time Ta of the clutch 5 is measured based on the acquired q-axis current value Id. The details are as follows.

When the transfer control unit 202 commands the connection, the measurement of the connection time Ta is started. The vector control unit 25 sequentially acquires the q-axis current value Iq output in a period (for example, 10 to 50 μs) sufficiently shorter than the assumed lower limit (for example, 1 ms) of the connection time Ta, and each time it is acquired, the q-axis The rate of change of the current value Iq is obtained. That is, the amount of change per unit time, which is the acquisition cycle, is obtained. The change in the q-axis current value Iq represents the change in the rotational torque Mt in the output shaft of the motor 3.

As shown in FIG. 7, when the clutch control signal S5 is off, a predetermined amount of rotational torque Mt for driving a load (photoreceptor or the like) other than the roller 14A is generated. When the gear portion 5A of the clutch 5 and the driven portion 5B start to slide, the rotational torque Mt begins to increase. As the dynamic friction force between the gear portion 5A and the driven portion 5B increases, the rotation speed of the roller 14A approaches the rotation speed of the gear portion 5A. The rotational torque Mt continues to increase.

When the rotational speed of the roller 14A becomes equal to the rotational speed of the gear portion 5A, that is, when the gear portion 5A and the driven portion 5B start to rotate integrally by the static friction force, the rotational torque Mt suddenly increases to a predetermined value. Become constant.

Therefore, the measuring unit 203 measures the time Ta1, Ta2, and Ta3 from the start of the measurement to the timing when the rate of change of the q-axis current value Iq suddenly increases as the connection time Ta. Whether or not the rate of change has increased sharply can be determined, for example, by whether or not the amount of change per unit time exceeds the threshold value. It may be determined by performing a process of determining the completion of the connection by using an analysis method that considers fluctuations in the q-axis current value Iq due to disturbance.

It should be noted that the connection may not be completed even if a predetermined time Tz, which is extremely long with respect to the assumed connection time Ta, elapses.

When measuring the coupling time Ta in this way, the measuring unit 203 acquires the difference between the q-axis current value Iq before and after the clutch 5 is engaged as the amount of change in the rotational torque Mt. This amount of change is caused by the application of the resist roller pair 14 as a load to the motor 3, and corresponds to the load torque Ct obtained by converting the load torque applied to the clutch 5 into the output shaft of the motor 3. That is, the measuring unit 203 measures (detects) the coupling time Ta and the load torque Ct (change amount of the rotational torque Mt) when the clutch 5 is engaged. In the measurement of the load torque Ct, the q-axis current value Iq first acquired in the measurement of the connection time Ta is stored as the q-axis current value Iq before connection.

FIG. 7 shows three cases in which the connection times Ta1, Ta2 and Ta3 and the load torques Ct1, Ct2 and Ct3 are different. Generally, when the load torque Ct is large (heavy), the connection time Ta is longer than when the load torque Ct is small (light).

Further, when the clutch 5 is released, the measuring unit 203 acquires the q-axis current value Iq from the vector control unit 25 in the same manner as when the clutch 5 is engaged, and measures the release time Tb based on the acquired q-axis current value Iq. At that time, the difference between the q-axis current value Iq before and after the clutch 5 is released is acquired as the amount of change in the rotational torque Mt (that is, the load torque Ct).

As shown in FIG. 8, at the time of release, the q-axis current value Iq is maintained at the value before release for a while after the clutch control signal S5 is switched from on to off, and then sharply decreases. Specifically, when the drive of the clutch 5 by the clutch drive unit 51 is stopped, the current flowing through the coil in the clutch 5 gradually decreases, and the torque generated by the clutch 5, that is, the driven unit from the gear unit 5A is accompanied by this. The rotational torque transmitted to 5B decreases. When the torque generated by the clutch 5 is smaller than the load torque applied to the driven portion 5B, the gear portion 5A and the driven portion 5B are separated from each other. That is, the release is completed. At this time, the q-axis current value Iq decreases at once by the amount of the load torque Ct. The release times Tb are the times Tb1 and Tb2 from when the clutch control signal S5 is turned off until the q-axis current value Iq decreases at once. Generally, the connection time Tb2 when the load torque Ct2 is small (light) is longer than the connection time Ta1 when the load torque Ct1 is large (heavy).

Returning to FIG. 6, the measuring unit 203 measures the passing time Tp, which is the time required for the seat 9 to pass through the resist roller pair 14, based on the signals from the seat sensors 19A and 19B. Since the transit time Tp changes depending on the slip of the sheet 9 during the transfer by the resist roller pair 14, it is one of the criteria for determining the quality of the surface condition of the resist roller pair 14.

The support processing unit 204 performs support processing for supporting the maintenance work of the image forming apparatus 1, particularly the work of preventing jam due to a defect in the clutch 5 and its peripheral portion, according to the measured value of the connection time Ta. The support processing unit 204 includes a discrimination unit 241, a notification processing unit 242, a data storage unit 243, a data processing unit 244, and the like.

As shown in FIG. 9, the determination unit 241 compares the measured value of the connection time Ta with the threshold values th1, th2, th3, and compares the measured value of the load torque Ct with the threshold values th11, th12. , The quality of the connection operation characteristic of the clutch 5 is determined.

In FIG. 9, the appropriate time range RTa is set from the threshold value th1 (for example, 3 ms) to the threshold value th2 (for example, 8 ms) for the connection time Ta. Regarding the load torque Ct, the appropriate torque range RCt is set from the threshold value th11 to the threshold value th12. The appropriate torque range RCt is an example of an appropriate change amount range.

Further, as shown in FIG. 10, the discriminating unit 241 compares the measured value of the release time Tb with the threshold value th21, and compares the measured value of the load torque Ct with the threshold value th31 to compare the clutch 5 with the threshold value th31. Determine whether the release operation characteristics are good or bad.

The notification processing unit 242 provides status information D5 related to jam prevention, such as various measured values obtained by the measuring unit 203, the results of discrimination by the discriminating unit 241 and the maintenance necessity Q calculated based on the measured values. Notification processing for notifying the service person is performed as support processing.

The notification process includes the following processes (1) to (3).
(1) In the maintenance mode, the process of displaying the status information on the operation panel 7 of the image forming apparatus 1 or the terminal device carried by the service person (2) The status information D5 is transmitted to the service center using the communication interface 8 in a timely manner. Process (3) Process of transmitting a message to the user to request a service person to take action With reference to FIG. 9 (B), the notification processing unit 242 has an upper limit (threshold value) of RTa in which the clutch 5 is engaged in an appropriate time range. If it is not completed even after Tz elapses for a longer time than th2), a notification process for notifying the service person that there is a problem with the clutch 5 is performed.

The notification processing unit 242 loads the motor 3 when the measured value of the connection time Ta is larger than the threshold value th2 and the measured value of the load torque Ct is larger than the upper limit of the appropriate torque range RCt (threshold value th12). Inform the service person that the torque tends to increase.

The notification processing unit 242 indicates that the operating characteristics of the clutch have begun to deteriorate when the measured value of the connection time Ta is larger than the threshold value th2 and the measured value of the load torque Ct is smaller than the threshold value th12. Inform the service person.

In the notification processing unit 242, the measured value of the connection time Ta is smaller than the lower limit of the appropriate time range RTa (threshold value th1), and the measured value of the load torque Ct is lower than the lower limit of the appropriate torque range RCt (threshold value th11). If it is small, inform the service person that the load on the resist rollers vs. 14 is starting to lighten.

With reference to FIG. 10, the notification processing unit 242 notifies the service person that the stop time of the resist roller pair 14 is long when the measured value of the release time Tb is larger than the threshold value 21. The details are as follows.

When the measured value of the release time Tb is larger than the threshold value 21 and the measured value of the load torque Ct is smaller than the threshold value 31, the load torque of the clutch 5 becomes lighter, so that the stop time of the resist roller vs. 14 is reduced. Inform that is getting longer.

Further, when the measured value of the release time Tb is larger than the threshold value 21 and the measured value of the load torque Ct is larger than the threshold value 31, the sliding resistance in the clutch 5 becomes large, so that the resist roller pair Notify that the downtime of 14 is getting longer. In this case, it may be notified that the cause of the increase in the sliding resistance is the mixing of foreign matter into the meshing surface of the gear portion 5A or the accumulation of dirt on the bearing.

The data storage unit 243 supports the state monitoring process when the measured value of the connection time Ta is outside the appropriate time range RTa or when the measured value of the load torque Ct is outside the appropriate torque range RCt. Perform as a process. The state monitoring process is a process of accumulating at least the measured value of the connection time Ta and the measured value of the load torque Ct as the monitoring data D50.

The data storage unit 243 stores the measured value of the transit time Tp as a part of the monitoring data D50 in the state monitoring process.

The data storage unit 243 uses the clutch 5 when the measured value of the connection time Ta is smaller than the threshold value th1 and the measured value of the load torque Ct is larger than the threshold value th11 during the execution of the condition monitoring process. It is determined that the status of and its surroundings is normal, and the status monitoring process is terminated.

Further, when the measured value of the connection time Ta is within the appropriate time range RTa and the load torque Ct is within the appropriate torque range RCt during the execution of the condition monitoring process, it is determined that the state of the clutch 5 and its surroundings is normal. And end the status monitoring process.

As a part of the state monitoring process, the data processing unit 244 performs data processing for predicting changes in the operating characteristics of the clutch 5 and the resist roller pair 14 based on the monitoring data D50. Specifically, the maintenance necessity Q is calculated based on the frequency and the amount of the measured value of the connection time Ta in the monitoring data D50 exceeding the set value (threshold value th3: for example, 20 to 30 ms) larger than the threshold value th2. do. The maintenance necessity Q is information indicating the susceptibility of the sheet 9 to jam, that is, the urgency of the coping work to prevent the jam. To calculate the maintenance necessity Q, an arithmetic expression derived from statistical analysis of past jam occurrence cases is used.

FIG. 11 shows an example of a processing flow in maintenance and inspection by a service person. In FIG. 11, it is assumed that the service person works at the installation location of the image forming apparatus 1.

The service person causes the image forming apparatus 1 to perform test printing. If it is known that a jam has occurred recently, a test print is executed as a reproduction test of the jam.

The image forming apparatus 1 measures at least the connection time Ta and the load torque Ct in the test printing (# 301), and notifies the service person of the obtained measured values (# 302). The connection operation characteristic may be discriminated and the result may be notified together with the measured value or in place of the measured value.

The service person conducts a peripheral survey targeting the clutch 5 and its vicinity, focusing on the part where the jam is suspected or is likely to occur, depending on the notified information (# 303 to # 309). ).

In this peripheral survey, the survey procedure is basically changed depending on whether the load torque Ct is relatively light or heavy.

That is, when the load torque Ct is light, the transport force may be reduced, so that the surface state of the rollers 14A and 14B and the state of the spring that sets the pressing force on the seat 9 by the rollers 14A and 14B. Start with a survey.

When the load torque Ct is heavy, the load may increase further. Therefore, foreign matter on the surface conditions of the rollers 14A and 14B and the gear group (including the gear portion 5A) connecting the clutch 5 and the motor 3 Start by investigating for adhesion and scratches.

The peripheral survey is carried out as follows according to the measured value of the connection time Ta.

When the measured value of the connection time Ta is smaller than the threshold value th1 (YES in # 303), it is investigated carefully especially when the load torque Ct is light (# 309). This is because when the load torque Ct is heavy, the short connection time Ta shows a preferable phenomenon due to the so-called familiarity of the friction surface of the clutch 5, so that there is almost no problem in the clutch 5 and its vicinity. ..

If any defects are found in the surrounding survey, necessary measures such as cleaning, repair, and parts replacement will be taken.

After that, the image forming apparatus 1 starts the state monitoring process when, for example, a predetermined operation for ending the maintenance mode is performed (# 312). At present, the clutch 5 is operating normally, but since the measured value of the connection time Ta is outside the appropriate time range RTa, information indicating the future condition is collected by performing the condition monitoring process.

If the measured value of the connection time Ta is within the appropriate time range RTa (NO for # 303, YES for # 304), the state of each part is confirmed in the peripheral survey (# 306).

If the measured value of the connection time Ta is larger than the threshold value th2 and equal to or less than the threshold value th3 (NO for # 304, YES for # 305), the connection completion is delayed. Conduct an investigation (# 308). In particular, when the load is heavy, carefully investigate the possible causes and possible parts. After that, the image forming apparatus 1 starts the state monitoring process.

If the measured value of the connection time Ta is larger than the threshold value th3 (NO at # 305), it is confirmed whether or not the load is heavy when conducting a peripheral survey (# 307). When the load is heavy, carefully investigate whether there is a cause for increasing the load other than the clutch 5. If the cause is not found, it is determined that the clutch 5 is defective and the clutch 5 is replaced (# 310).

When the service person determines that it is necessary to confirm the state of transportation of the sheet 9 after conducting the peripheral survey (# 313), the service person causes the image forming apparatus 1 to perform test printing again.

FIG. 12 shows the flow of the state monitoring process in the image forming apparatus 1.

The status monitoring mode is set (# 401), and each time a print job is executed, the connection time Ta, load torque Ct, release time Tb, passage time Tp, etc. are measured (# 402), and the obtained measured values are measured. It is stored as monitoring data D50 (# 403). Further, the transport conditions such as the paper type of the sheet 9 are recorded in association with the measured values.

Data processing for calculating maintenance necessity Q is performed periodically (# 404), and the processing result is recorded so that it can be read by a service person (# 405).

If the processing result is within the setting range that does not require early maintenance work and the measured value does not satisfy the condition for ending monitoring (YES for # 406, NO for # 407), step # 402 is performed. Go back and continue monitoring the status.

If the result of data processing is out of the set range, for example, if the maintenance requirement Q is 80% or more (NO in ## 406), turn on the maintenance flag (# 408) and prompt the user to contact the service person. Service call processing is performed (# 409).

According to the above embodiment, since the connection time Ta is measured based on the q-axis current value Iq, an accurate measured value can be easily obtained as compared with the measurement based on the value of the total current flowing through the motor 3. Since the condition of the clutch 5 can be determined based on the accurate measured value of the connection time Ta and necessary measures can be taken, the efficiency of maintenance work for preventing the occurrence of jam is improved.

Since the load torque Ct can be easily measured based on the q-axis current value Iq and the load torque applied to the clutch 5 can be easily obtained based on the load torque Ct, not only the clutch 5 but also the roller 14A and its driving force can be easily obtained. It is possible to determine the condition of each part of the mechanism for transmitting the load torque based on the measured value of the load torque Ct and take necessary measures. This makes maintenance work more efficient.

In the embodiment described above, the measured values such as the connection time Ta and the load torque Ct, and the monitoring data D50 may be uploaded to the service center at any time via the communication line. In that case, the service person can grasp the condition of the clutch 5 of the image forming apparatus 1 while staying at the service center. The timing of maintenance work can be determined according to the condition of the clutch 5, and the timing of transporting the seat 9 can be adjusted by remote control.

In the embodiment described above, the values of the threshold values th1 to th3 and the time Tz of the connection time Ta are not limited to the exemplary values. It may be a value corresponding to the load torque of the clutch 5.

The roller that is rotationally driven via the clutch 5 may be a roller other than the resist roller pair 14.

In addition, the configuration of the entire image forming apparatus 1 or each part, the content, order or timing of processing, the number of threshold values used for determining the connection time Ta and the load torque Ct, the configuration of the motor 3, and the like are the objects of the present invention. It can be changed as appropriate according to.

1 Image forming device 3 Motor 5 Clutch 9 Seat 14 Resist roller pair (roller)
19A, 19B seat sensor (sensor)
21 Motor control device (motor control unit)
203 Measuring unit 204 Support processing unit Ct Load torque (change amount of rotational torque)
D50 Monitoring data IQ q-axis current value (current detection value)
Mt Rotational torque Q Maintenance necessity RCt Appropriate torque range (appropriate change amount range)
RTa Appropriate time range th21 Threshold Ta Connection time Tb Release time Tp Transit time Tz time

Claims (17)

An image forming device that forms an image on a sheet.
A roller for transporting the sheet and
A motor for rotationally driving the roller and
A motor control unit that vector-controls the motor and
A clutch that transmits the rotational driving force of the motor to the roller,
A measuring unit that acquires a detected value of a current that flows through the motor and generates a rotational torque from the motor control unit and measures the clutch engagement time based on the detected value.
It has a support processing unit that performs support processing for supporting maintenance work according to the measured value of the connection time.
An image forming apparatus characterized in that. The support processing unit notifies the service person that there is a problem with the clutch when the clutch engagement operation is not completed even after a predetermined time longer than the upper limit of the appropriate time range has elapsed. As the support process,
The image forming apparatus according to claim 1. When measuring the coupling time, the measuring unit acquires the difference between the detected values before and after the clutch is engaged as the amount of change in the rotational torque.
When the measured value of the connection time is a value outside the appropriate time range, the support processing unit performs a state monitoring process of accumulating the measured value of the connection time and the amount of change as monitoring data as the support process. ,
The image forming apparatus according to claim 1. When measuring the coupling time, the measuring unit acquires the difference between the detected values before and after the clutch is engaged as the amount of change in the rotational torque.
When the change amount is a value outside the appropriate change amount range, the support processing unit performs a state monitoring process for accumulating the measured value of the connection time and the change amount as monitoring data as the support process.
The image forming apparatus according to claim 1. The support processing unit tends to increase the load torque of the motor when the measured value of the connection time is larger than the upper limit of the appropriate time range and the change amount is larger than the upper limit of the appropriate change amount range. The notification process for notifying the service person of the fact that the service person is in the service person is performed as the support process.
The image forming apparatus according to any one of claims 3 or 4. When the measured value of the connection time is larger than the upper limit of the appropriate time range and the amount of change is smaller than the upper limit of the appropriate change amount range, the support processing unit starts to deteriorate the operating characteristics of the clutch. The notification process for notifying the service person that the service person is present is performed as the support process.
The image forming apparatus according to any one of claims 3 to 5. When the measured value of the connection time is smaller than the lower limit of the appropriate time range and the amount of change is smaller than the lower limit of the appropriate change amount range, the support processing unit starts to reduce the load on the roller. The notification process for notifying the service person is performed as the support process.
The image forming apparatus according to any one of claims 3 to 6. The condition monitoring process includes data processing for predicting changes in the operating characteristics of the clutch and the roller based on the monitoring data.
The image forming apparatus according to any one of claims 3 to 7. The support processing unit needs to maintain the susceptibility to jam of the sheet based on the frequency and the amount of the measured value of the connection time in the monitoring data exceeding the set value larger than the upper limit of the appropriate time range. The process of calculating the degree is performed as the data process, and the notification process for notifying the service person of the calculated maintenance necessity is performed as the support process.
The image forming apparatus according to claim 8. It has sensors provided on the upstream side and the downstream side of the roller in the sheet transport path and output a signal indicating the presence or absence of the sheet.
Based on the signal from the sensor, the measuring unit measures the passing time, which is the time required for the sheet to pass through the roller.
In the state monitoring process, the support processing unit accumulates the measured value of the transit time as a part of the monitoring data.
The image forming apparatus according to claim 8. The data processing unit performs a process of calculating the likelihood of jamming of the sheet as a maintenance necessity based on the frequency and amount of the measured value of the connection time in the monitoring data exceeding a predetermined value. In addition, the notification process for notifying the service person of the calculated maintenance necessity is performed as the support process.
The image forming apparatus according to claim 10. When the measured value of the connection time is smaller than the lower limit of the appropriate time range and the change amount is larger than the lower limit of the appropriate change amount range during the execution of the state monitoring process. , End the status monitoring process,
The image forming apparatus according to claim 3. The support processing unit performs the state monitoring process when the measured value of the connection time is within the appropriate time range and the change amount is within the appropriate change amount range during the execution of the state monitoring process. finish,
The image forming apparatus according to claim 3. The measuring unit measures the disengagement time of the clutch based on the detected value of the current.
The support processing unit performs notification processing as the support processing for notifying the service person that the stop time of the roller is long when the measured value of the release time is larger than the threshold value.
The image forming apparatus according to any one of claims 1 to 13. The measuring unit measures the release time of the clutch based on the detected value of the current, and when measuring the release time, the difference between the detected values before and after the clutch is released is determined. Obtained as the amount of change
When the measured value of the release time is larger than the threshold value and the amount of change at the time of release is smaller than the threshold value, the support processing unit reduces the load torque of the clutch, so that the roller As the support process, a notification process for notifying the service person that the stop time is long is performed.
The image forming apparatus according to any one of claims 3 to 13. When the measured value of the release time is larger than the threshold value and the amount of change at the time of release is larger than the threshold value, the support processing unit increases the sliding resistance in the clutch. As the support process, a notification process for notifying the service person that the stop time of the roller is long is performed.
The image forming apparatus according to claim 15. It is a method of supporting maintenance work of an image forming apparatus having a clutch for transmitting the rotational driving force of a motor to a roller that conveys a sheet and vector-controlling the motor.
The clutch engagement time is measured by the image forming apparatus based on the detected value of the current flowing through the motor and generating the rotational torque acquired in the vector control.
By comparing the measured value of the connection time with a plurality of threshold values, the image forming apparatus determines whether or not the operating characteristics of at least the clutch among the parts related to the transfer of the sheet are good or bad, and the determination thereof. Notify the result,
A method of supporting maintenance work, which is characterized by the fact that.

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