JP2021056487A - Image forming apparatus, motor control unit for controlling motor, and method for controlling motor - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a technique for determining whether or not a cause of a motor start failure is a motor failure. An image forming apparatus controls a motor, a transmission mechanism for transmitting a driving force of the motor to a load, and the motor so as to rotate a rotor of the motor in a first direction in order to rotate the load. The transmission mechanism has a backlash, and the control means reverses the rotor to the first direction if the control to rotate the rotor in the first direction fails. By controlling the rotation of the rotor in the second direction by a predetermined amount, it is determined whether or not the control of rotating the rotor in the first direction has failed due to the failure of the motor. [Selection diagram] FIG. 7

Description

The present invention relates to a motor control technique.

As a drive source for the rotating member of the image forming apparatus, a sensorless type motor (hereinafter referred to as a sensorless motor) that does not have a sensor for detecting the position of a rotor such as a Hall element is used. Patent Document 1 discloses a configuration in which the rotor position of a sensorless motor is detected by an induced voltage generated in a coil.

Japanese Unexamined Patent Publication No. 8-223970

In order to detect the rotor position (rotational phase of the rotor) of the sensorless motor in a stopped state where no induced voltage is generated, the characteristic that the inductance value of the coil changes according to the rotor position is used. Specifically, the rotor position can be determined by detecting the inductance value of the coil based on the coil current flowing through the coil when a predetermined voltage is applied to the coil. Then, the motor is driven by forced commutation control until the rotor position can be detected from the induced voltage, and when the rotor position can be detected from the induced voltage, the motor is switched to sensorless drive. If the rotation speed of the rotor estimated from the coil current is not within the predetermined speed range after the motor is started to be driven, the start failure occurs.

In this way, it is possible to determine the motor start failure from the rotor rotation speed, but it is not possible to determine from the rotor rotation speed whether the cause of this start failure is due to a motor failure or an abnormality in the motor load.

The present invention provides a technique for determining whether or not the cause of a motor start failure is a motor failure.

According to one aspect of the present invention, the image forming apparatus is such that the motor, the transmission mechanism that transmits the driving force of the motor to the load, and the rotor of the motor are rotated in the first direction in order to rotate the load. The transmission mechanism includes a control means for controlling the motor, and the control means causes the rotor to rotate in the first direction when the control for rotating the rotor in the first direction fails. By controlling the rotation of the rotor in the second direction opposite to the direction by a predetermined amount, it is determined whether or not the control of rotating the rotor in the first direction has failed due to the failure of the motor.

According to the present invention, it is possible to determine whether or not the cause of the motor start failure is a motor failure.

The block diagram of the image forming apparatus by one Embodiment. FIG. 6 is a drive configuration diagram of a photoconductor according to an embodiment. A control configuration diagram of a motor according to an embodiment. The block diagram of the motor according to one Embodiment. The figure which shows the relationship between the exciting phase and the combined inductance, and the detection method of the combined inductance. The explanatory view of the motor start process by one Embodiment. A flowchart of a cause identification process according to an embodiment. The drive block diagram of the fixing part by one Embodiment. A flowchart of a cause identification process according to an embodiment.

Hereinafter, embodiments will be described in detail with reference to the accompanying drawings. The following embodiments do not limit the invention according to the claims. Although a plurality of features are described in the embodiment, not all of the plurality of features are essential to the invention, and the plurality of features may be arbitrarily combined. Further, in the attached drawings, the same or similar configurations are designated by the same reference numbers, and duplicate explanations are omitted.

<First Embodiment>
FIG. 1 is a configuration diagram of an image forming apparatus according to the present embodiment. The image forming apparatus of FIG. 1 superimposes toner images of four colors of yellow, magenta, cyan, and black to form a full-color image. In FIG. 1, Y, M, C and K at the end of the reference reference numerals indicate that the colors of the toner image in which the member indicated by the reference reference numeral is involved in formation are yellow, magenta, cyan and black, respectively. .. In the following description, when it is not necessary to distinguish the colors, a reference code excluding the trailing Y, M, C and K is used. The photoconductor 13 is rotationally driven in the clockwise direction shown in the figure at the time of image formation. The charging roller 15 charges the surface of the corresponding photoconductor 13 to a uniform potential. The exposure unit 11 exposes the surface of the corresponding photoconductor 13 with light to form an electrostatic latent image on the photoconductor 13. The developing roller 16 of the developing unit 12 develops the electrostatic latent image of the corresponding photoconductor 13 with toner and visualizes it as a toner image. The primary transfer roller 18 transfers the toner image formed on the corresponding photoconductor 13 to the intermediate transfer belt 19 by the primary transfer bias. The cleaner 14 removes the toner that is not transferred to the intermediate transfer belt 19 and remains on the corresponding photoconductor 13. A full-color image is formed on the intermediate transfer belt 19 by superimposing and transferring the toner image formed on each photoconductor 13 on the intermediate transfer belt 19.

The intermediate transfer belt 19 is rotationally driven in the counterclockwise direction shown in the figure at the time of image formation. As a result, the toner image transferred to the intermediate transfer belt 19 is conveyed to the opposite position of the secondary transfer roller 29. On the other hand, the sheet 21 stored in the cassette 22 is fed from the cassette 22 to the transport path by the rotation of each roller provided along the transport path, and is transported to the opposite position of the secondary transfer roller 29. The secondary transfer roller 29 transfers the toner image of the intermediate transfer belt 19 to the sheet 21 by the secondary transfer bias. After that, the sheet 21 is conveyed to the fixing portion 30. The fixing unit 30 heats and pressurizes the sheet 21 to fix the toner image on the sheet 21. After fixing the toner image, the sheet 21 is discharged to the outside of the image forming apparatus. The control unit 31 that controls the entire image forming apparatus includes a CPU 32.

FIG. 2 shows the drive configurations of the photoconductors 13Y, 13M and 13C. The drive transmission gear of the motor 101 and the drive transmission gears of the photoconductors 13Y, 13M and 13C are connected by the couplings 17Y, 17M and 17C, respectively. Therefore, the driving force of the motor 101 is transmitted to the photoconductors 13Y, 13M and 13C via the couplings 17Y, 17M and 17C. The photoconductors 13Y, 13M and 13C can be removed from the image forming apparatus by disconnecting the drive transmission gears in the couplings 17Y, 17M and 17C. The couplings 17Y, 17M and 17C are provided with backlash so that the gears can be smoothly connected when the photoconductors 13Y, 13M and 13C are attached.

FIG. 3 is a control configuration diagram of the motor 101. The motor control unit 120 includes a microcomputer (hereinafter referred to as a microcomputer) 121. The communication port 122 of the microcomputer 121 performs serial communication with the control unit 31. The control unit 31 controls the rotation of the motor 101 by controlling the motor control unit 120 via serial communication. The reference clock generation unit 125 generates a reference clock based on the output of the crystal oscillator 126. The counter 123 measures the pulse cycle and the like based on this reference clock. The non-volatile memory 124 stores a program used for controlling the motor, various data, and the like. The microcomputer 121 outputs a pulse width modulation signal (PWM signal) from the PWM port 127. In the present embodiment, the microcomputer 121 has a high side PWM signal (UH, VH, WH) and a low side PWM signal for each of the three phases (U, V, W) of the motor 101. A total of 6 PWM signals (UL, VL, WL) are output. Therefore, the PWM port 127 has six terminals UH, VH, WH, UL, VL, and WL.

Each terminal of the PWM port 127 is connected to the gate driver 132, and the gate driver 132 controls on / off of each switching element of the three-phase inverter 131 based on the PWM signal. The inverter 131 has a total of six switching elements, three on the high side and three on the low side for each phase, and the gate driver 132 controls each switching element based on the corresponding PWM signal. As the switching element, for example, a transistor or FET can be used. In the present embodiment, when the PWM signal is high, the corresponding switching element is turned on, and when it is low, the corresponding switching element is turned off. The output 133 of the inverter 131 is connected to the coils 135 (U phase), 136 (V phase) and 137 (W phase) of the motor 101. By controlling each switching element of the inverter 131 on and off, the exciting current (coil current) of each coil 135, 136, 137 can be controlled. In this way, the microcomputer 121, the gate driver 132, and the inverter 131 function as a voltage control unit that controls the voltage applied to the plurality of coils 135, 136, and 137.

The current sensor 130 outputs a detection voltage corresponding to the value of the coil current flowing through each coil 135, 136, 137. The amplification unit 134 amplifies the detection voltage of each phase, applies an offset voltage, and outputs the output to the analog-to-digital converter (AD converter) 129. The AD converter 129 converts the detected voltage after amplification into a digital value. The current value calculation unit 128 determines the coil current of each phase based on the output value (digital value) of the AD converter 129. For example, the current sensor 130 outputs a voltage of 0.01 V per 1 A, the amplification factor (gain) in the amplification unit 134 is 10 times, and the offset voltage applied by the amplification unit 134 is 1.6 V. Assuming that the range of the coil current flowing through the motor 101 is −10A to + 10A, the voltage range output by the amplification unit 134 is 0.6V to 2.6V. For example, if the AD converter 129 converts a voltage of 0 to 3V into a digital value of 0 to 4095 and outputs it, the exciting current of -10A to + 10A is converted to a digital value of approximately 819 to 3549. To. The positive current value is defined as the exciting current flowing in the direction from the inverter 131 to the motor 101, and the opposite is defined as the negative current value.

The current value calculation unit 128 obtains the exciting current by subtracting the offset value corresponding to the offset voltage from the digital value and multiplying it by a predetermined conversion coefficient. In this example, the offset value corresponding to the offset voltage (1.6V) is about 2184 (1.6 × 4095/3). The conversion coefficient is about 0.000733 (3/4095). In this way, the current sensor 130, the amplification unit 134, the AD converter 129, and the current value calculation unit 128 constitute the current detection unit.

FIG. 4 is a configuration diagram of the motor 101. The motor 101 is a sensorless motor. The motor 101 includes a 6-slot stator 71 and a 4-pole rotor 72, and the stator 71 includes U-phase, V-phase, and W-phase coils 135, 136, and 137. The rotor 72 is composed of permanent magnets and includes two sets of N poles / S poles. The position where the rotor 72 stops is determined according to the combination of the coils 135, 136 and 137 being excited, that is, the exciting phase. Since the rotor 72 rotates, the position of the rotor 72 is also the rotation phase of the rotor 72. For example, when the coil current is excited so as to flow from the U-phase coil 135 to the V-phase coil 136, the rotor 72 stops at the position shown in FIG. 4 (A). When a coil current is passed from the U-phase coil 135 to the V-phase coil 136, the U-phase becomes the N-pole and the V-phase becomes the S-pole. After that, when the coil current is excited so as to flow from the U-phase coil 135 to the W-phase coil 137, the U-phase becomes the N-pole and the W-phase becomes the S-pole, and the rotor 72 stops at the position shown in FIG. 4 (B). To do.

In the following description, the two phases to be excited will be referred to as an exciting phase. When the exciting phase is the XY phase, a coil current is passed from the X-phase coil to the Y-phase coil to excite. At this time, it is assumed that the X phase becomes the N pole and the Y phase becomes the S pole. When the drive of the motor 101 is stopped so that the coil current does not flow, the force for holding the rotor 72 does not work. In this state, when an external force is applied to the rotor 72, the rotor 72 rotates. Further, when the power of the image forming apparatus is turned on, the image forming apparatus does not know the stop position of the rotor 72. Therefore, when starting the rotation of the motor 101 by the forced commutation control, the image forming apparatus must first detect the stop position of the rotor 72.

Generally, the coil has a structure in which a copper wire is wound around a core in which electromagnetic steel plates are laminated. Here, the magnetic permeability of the electromagnetic steel sheet becomes small when there is an external magnetic field. Therefore, the inductance of the coil, which is proportional to the magnetic permeability of the core, becomes smaller in the presence of an external magnetic field. For example, in a state where only the S poles of the rotor 72 face each other as in the U-phase coil 135 in FIG. 4A, the influence of the external magnetic field by the rotor 72 is large, so that the inductance of the U-phase coil 135 is large. The rate of decrease is large. When there is an external magnetic field, when the direction of the magnetic field generated by the coil current is the same as the direction of the external magnetic field, the amount of decrease in inductance is larger than in the case of the opposite direction. In the state of FIG. 4A, since the S pole of the rotor 72 faces the U phase, the amount of decrease in inductance when the coil current is passed in the direction in which the U phase is the N pole is the U phase. It is larger than when the coil current is passed in the direction of the S pole.

On the other hand, in the state of FIG. 4A, since the intermediate portion between the S pole and the N pole of the rotor 72 faces the W-phase coil 137, the influence of the external magnetic field by the rotor 72 is small and the inductance is reduced. The rate becomes smaller. In this way, the inductances of the U-phase coil 135, the V-phase coil 136, and the W-phase coil 137 change according to the stop position of the rotor 72. FIG. 5 (A) shows an example of the combined inductance when each exciting phase is excited when the rotor 72 is stopped in the state of FIG. 4 (A). In the following description, the position where the rotor 72 stops when the XY phase is excited is referred to as the "XY phase position".

Since the rotor 72 is stopped at the position of the UV phase, as shown in FIG. 5A, the combined inductance of the UV phase when the UV phase is excited is the smallest. Therefore, the stop position of the rotor 72 can be determined by obtaining and comparing the combined inductance of each exciting phase by exciting each exciting phase. In the following description, exciting the exciting phase, obtaining the combined inductance of the excited phase, and determining the relative magnitude relationship is referred to as relative value detection processing.

In the present embodiment, all six exciting phases are excited in order, and the combined inductance is determined by measuring the coil current after a predetermined time. The smaller the combined inductance, the faster the coil current rises. Therefore, when the rotor 72 is stopped at the position of the U-V phase, the coil current after a predetermined time when the U-V phase is excited is different. It becomes larger than the case where the excitation phase of is excited. It is assumed that the rotor 72 is stopped in the middle of two electrically adjacent exciting phases, that is, in the middle of, for example, the position of the UV phase and the position of the UW phase. In this case, the coil currents after a predetermined time when the UV phase is excited and when the UW phase is excited are about the same value, and are larger than when the other exciting phases are excited. In the present embodiment, when the coil current when exciting any one of the exciting phases is larger than the coil current when the other exciting phase is excited, the rotor 72 is stopped at the position of the one exciting phase. Is determined. If the coil currents when two exciting phases that are electrically adjacent to each other are excited are of the same value and larger than when the other exciting phases are excited, the position is set to the intermediate position between the two exciting phases. It is determined that the rotor 72 is stopped.

Hereinafter, the relative value detection process of the present embodiment will be specifically described. For example, when the UV phase is excited, a PWM signal whose duty changes as shown in FIG. 5B is output from the UH terminal and the VH terminal of the PWM port 127. Specifically, in the A section (0.5 ms), the duty of the PWM signal output from the UH terminal is changed to a half-wave sine wave shape. The maximum value of duty is, for example, 80%. During this period, the VL terminal is set to a high level (duty 100%), and the other terminals are set to a low level (duty 0%). In the B section (0.5 ms) following the A section, the duty of the PWM signal output from the VH terminal is changed to a half-wave sine wave shape. During this period, the UL terminal is set to a high level (duty 100%), and the other terminals are set to a low level (duty 0%). The periods of the A section and the B section are determined so as to ensure the detection accuracy and not to rotate the rotor 72, and are set to 0.5 ms in each of the present embodiments. The maximum value of the duty in the A section is determined so that the coil current having sufficient detection accuracy flows. Further, the maximum value of the duty in the B section is set so that the sum of the voltage-time products generated in the inductance components of the coils in the A section and the B section is approximately zero. By setting in this way, as shown in FIG. 5B, the coil current smoothly decreases during the B section, and the coil current becomes substantially 0 at the end of the B section.

FIG. 6 is an explanatory diagram of the start processing of the motor 101. In the following description, the rotation direction of the rotor 72 for rotating the photoconductors 13Y, 13M and 13C in the rotation direction at the time of image formation is referred to as a forward direction, and the direction opposite to the forward direction is referred to as a reverse direction. And. First, the control unit 31 performs relative value detection processing to detect the stop position of the rotor 72. When the stop position of the rotor 72, that is, the initial position at the start of rotation is detected, the control unit 31 performs forced commutation control based on the initial position to rotate the rotor 72 in the forward direction. In the forced commutation control, the control unit 31 gradually speeds up the switching of the exciting phase, thereby increasing the rotation speed of the rotor 72. When the rotation speed of the rotor 72 reaches a predetermined threshold value, the motor control unit 120 switches from forced commutation control to sensorless drive. In the sensorless drive, the position and rotation speed of the rotor 72 are estimated based on the induced voltage. During the forced commutation control period, the control unit 31 determines the rotation speed of the rotor 72 based on the switching speed of the exciting phase. The control unit 31 detects the rotation speed of the rotor 72 at the abnormality determination timing, and when the detected rotation speed of the rotor 72 is smaller than the predetermined speed, the control unit 31 starts the motor 101, that is, directs the rotor 72 in the forward direction. It is determined that the control to rotate to is unsuccessful. At the abnormality determination timing, it is assumed that the control unit 31 controls the rotor 72 to rotate at a rotation speed faster than the predetermined speed.

In this way, the control unit 31 can detect the failure to start the motor 101 from the rotation speed of the rotor 72, but determines whether the cause of the failure is the failure of the motor 101 or the load abnormality of the motor 101. Can not do it. Here, as described with reference to FIG. 2, the couplings 17Y, 17M and 17C are provided with backlashes. Therefore, if it is within the backlash amount, the rotor 72 can be rotated in the opposite direction without the power of the motor 101 being transmitted to the load. That is, if the motor 101 is normal, the rotor 72 can be rotated in the opposite direction with a rotation amount within the backlash amount. If the motor 101 is out of order, the rotor 72 cannot be rotated in the reverse rotation direction. In the present embodiment, if the start of the motor 101 fails at the abnormality determination timing, the cause identification process described below is executed by utilizing the above characteristics.

FIG. 7 is a flowchart of the cause identification process according to the present embodiment. The control unit 31 performs a relative value detection process in S10 to detect the stop position A of the rotor 72. In S11, the control unit 31 rotates the rotor 72 in the reverse direction by a predetermined amount by forced commutation control. The amount of rotation in the reverse direction is less than or equal to the amount of backlash in the couplings 17Y, 17M and 17C. That is, the amount of rotation in the reverse direction is an amount in which the power of the motor 101 is not transmitted to the photoconductors 13Y, 13M, and 13C, which are loads, so that the load of the motor 101 becomes substantially 0. Further, the amount of rotation in the reverse direction is set so that the stop position of the rotor 72 after rotation in the reverse direction does not become the stop position A. The control unit 31 performs a relative value detection process in S12 to detect the stop position B of the rotor 72. The control unit 31 determines in S13 whether or not the stop position A and the stop position B are the same. Since the fact that the stop position A and the stop position B are the same means that the rotor 72 is not rotating, the control unit 31 determines in S14 that the motor 101 has failed. On the other hand, if the stop position A and the stop position B are not the same, the motor control unit 120 determines in S15 that the load is abnormal, that is, the photoconductors 13Y, 13M and 13C have failed.

By the process of FIG. 7, the control unit 31 can determine whether the cause of the start failure of the motor 101 is a failure of the motor 101 or a load abnormality of the motor 101. The control unit 31 can notify the user whether the photoconductors 13Y, 13M, 13C, which are loads, should be replaced or the motor 101 should be replaced, depending on the determination result.

As described above, a backlash is provided in the transmission mechanism for transmitting the power of the motor 101 to the load so that the power is not transmitted to the load even if the rotor 72 is rotated in the reverse direction by the amount of the backlash. That is, the motor 101 is configured so that it can rotate in the reverse direction with almost no load by the amount of backlash. Then, when the start of the motor 101 fails, the rotor 72 is rotated in the reverse direction by a predetermined amount within the backlash amount, and it is determined whether or not the rotor 72 is rotating in the reverse direction. With this configuration, it is possible to determine whether the start failure of the motor 101 is due to a load abnormality or a failure of the motor 101 itself. In this example, the couplings 17Y, 17M and 17C are provided with backlashes, but the present invention is not limited to such a configuration. Specifically, the backlash may be provided in the transmission mechanism that transmits the power of the motor 101 to the load (photoreceptor).

In S13 of FIG. 7, if the stop position A and the stop position B are the same, it is determined that the motor 101 has failed, and in other cases, it is determined that the load is abnormal. However, if the difference (phase difference) between the stop position A and the stop position B is smaller than a predetermined value, it may be determined that the motor 101 has failed, and in other cases, it may be determined that the load is abnormal. In this case, the predetermined amount to be rotated in the opposite direction in S11 is set to an amount that makes the phase difference between the stop position A and the stop position B equal to or more than the predetermined value.

Further, assuming that the rotor 72 at the stop position A has rotated in the reverse direction by a predetermined amount, the calculated stop position Z of the rotor 72 after the reverse rotation is obtained, and the actual stop position B and the stop position Z detected in S12. It is also possible to determine whether or not the motor 101 is out of order by comparing with. In this case, if the phase difference between the stop position Z and the stop position B is equal to or greater than a predetermined value, it is determined that the motor has failed, and if it is smaller than the predetermined value, it is determined that the load is abnormal. In this case, the predetermined amount to be rotated in the opposite direction in S11 is set to the predetermined value or more.

<Second embodiment>
Subsequently, the second embodiment will be described focusing on the differences from the first embodiment. FIG. 8 shows the drive configuration of the fixing unit 30. The fixing portion 30 includes a heating roller and a pressurizing roller 203, and the heating roller rotates depending on the rotation of the pressurizing roller 203. The motor 102 transmits the power to the pressurizing roller 203 and the contact separation mechanism 207 via the driving force transmission mechanism. The transmission mechanism is configured to transmit the power to the pressurizing roller 203 when the motor 102 rotates in the forward direction, and transmit the power to the contact separation mechanism 207 when the motor 102 rotates in the opposite direction. To. The contact separation mechanism 207 operates a cam (not shown) in response to the rotation of the motor 102 to bring the pressurizing roller 203 into contact with the heating roller and a contact state in which the pressure roller 203 is separated from the heating roller. Is configured to set the fixing unit 30 in. A sensor (not shown) detects whether the fixing portion 30 is in the contact state or the separated state. The image forming apparatus suppresses deterioration of the heating roller by separating the fixing portions 30 when the power is turned off or when the mode is changed to the sleep mode, and suppresses the occurrence of image defects due to defects in the heating rollers. The configuration of the motor 102 and its control configuration are the same as the configuration of the motor 101 and its control configuration, and the description thereof will be omitted.

FIG. 9 is a flowchart of the cause identification process according to the present embodiment. The control unit 31 performs a relative value detection process in S20 to detect the stop position C of the rotor 72. In S21, the control unit 31 rotates the rotor 72 in the reverse direction by forced commutation control, and when the rotation speed of the rotor 72 exceeds the threshold value, in S22, the rotor 72 is rotated in the reverse direction by sensorless drive. In S23, the control unit 31 determines whether the rotation speed of the rotor 72 is equal to or higher than a predetermined speed. That is, the processes of S20 to S23 are the same as the determination of the start failure when the rotor 72 is rotated in the forward direction, and are also performed in the reverse rotation. It should be noted that the predetermined speeds for determining the start failure in the forward direction and the reverse direction do not have to be the same.

In S23, if the rotation speed of the rotor 72 is not equal to or higher than the predetermined speed, the control unit 31 determines in S27 that the motor 102 has failed. On the other hand, if the rotation speed of the rotor 72 is equal to or higher than the predetermined speed in S23, the control unit 31 determines in S24 that the fixing unit 30 has failed. Further, the control unit 31 determines in S25 whether the fixing unit 30 is in a separated state by a sensor (not shown). In the separated state, the fixing portion 30 determines that the fixing portion 30 is out of order, but the contact separating mechanism 207 is normal. On the other hand, if the separated state is not reached, the fixing portion 30 determines in S26 that the contact separating mechanism 207 in addition to the fixing portion 30 has failed.

As described above, the transmission mechanism is configured so that power is transmitted to different loads depending on the rotation direction of the motor 102. If the start fails in both directions, it is determined that the motor 102 has failed. On the other hand, if the start in one rotation direction fails but the start in the other rotation direction succeeds, it is determined that the load that rotates when the motor 102 is rotated in the one rotation direction is abnormal. With this configuration, it is possible to determine whether the start failure of the motor 102 is due to a load abnormality or a failure of the motor 102 itself.

<Others>
In the first embodiment, the load is a photoconductor, and in the second embodiment, the load is the fixing portion 30 and the contact separation mechanism 207, but the load is not limited thereto. Specifically, if a transmission mechanism configured to rotate in the opposite direction by a predetermined amount with substantially no load is used, the configuration of the first embodiment can be applied to an arbitrary load. Further, if a transmission mechanism configured to transmit power to different loads depending on the rotation direction is used, the configuration of the second embodiment can be applied to an arbitrary load. Further, in each of the above embodiments, if the rotation speed does not reach a predetermined value at the abnormality determination timing, it is determined that the start-up has failed, but the start-up failure may be determined based on other criteria.

Further, although each of the above embodiments has been described by taking an image forming apparatus as an example, the present invention can be applied to any device that transmits the power of the motor to the load by utilizing the above transmission mechanism. Further, the present invention can also be realized as a motor control device that controls a motor that transmits power to a load by utilizing the above-mentioned transmission mechanism. The motor control device includes a motor control unit 120 of FIG. 3 and a functional block related to motor control of the control unit 31. Further, the present invention can also be realized as a method for controlling a motor in the motor control device.

[Other Embodiments]
The present invention supplies a program that realizes one or more functions of the above-described embodiment to a system or device via a network or storage medium, and one or more processors in the computer of the system or device reads and executes the program. It can also be realized by the processing to be performed. It can also be realized by a circuit (for example, ASIC) that realizes one or more functions.

The invention is not limited to the above embodiments, and various modifications and modifications can be made without departing from the spirit and scope of the invention. Therefore, a claim is attached to make the scope of the invention public.

101: Motor, 17Y, 17M, 17C: Coupling, 31: Control unit

Claims (21)

With the motor
A transmission mechanism that transmits the driving force of the motor to the load,
A control means for controlling the motor so as to rotate the rotor of the motor in the first direction in order to rotate the load.
With
The transmission mechanism has backlash and
When the control for rotating the rotor in the first direction fails, the control means controls the rotor to rotate in a second direction opposite to the first direction by a predetermined amount, thereby causing the motor to rotate. An image forming apparatus for determining whether or not the control for rotating the rotor in the first direction has failed due to a failure. The image forming apparatus according to claim 1, wherein the predetermined amount is equal to or less than the backlash amount of the backlash. In the control means, the phase difference between the rotation phase of the rotor before rotating the rotor in the second direction and the rotation phase of the rotor after rotating the rotor in the second direction is greater than a predetermined value. The image forming apparatus according to claim 2, wherein if it is small, it is determined that the motor has failed. The image forming apparatus according to claim 3, wherein the predetermined amount is an amount that makes the phase difference equal to or more than the predetermined value. The control means has a rotation phase of the rotor after the rotor is rotated in the second direction, and a rotation phase of the rotor when it is assumed that the rotor is rotated by the predetermined amount in the second direction. The image forming apparatus according to claim 2, wherein when the phase difference between the two is equal to or greater than a predetermined value, it is determined that the motor has failed. The image forming apparatus according to claim 5, wherein the predetermined amount is an amount equal to or more than the predetermined value. According to claim 1, if the control means does not determine that the motor has failed as a result of controlling the rotor to rotate in the second direction by the predetermined amount, it determines that the load has failed. The image forming apparatus according to any one of 6. The control means controls to rotate the rotor in the first direction at a rotation speed higher than a predetermined speed, detects the rotation speed of the rotor, and when the detected rotation speed of the rotor is smaller than the predetermined speed, The image forming apparatus according to any one of claims 1 to 7, wherein it is determined that the control for rotating the rotor in the first direction has failed. The image forming apparatus according to any one of claims 1 to 8, wherein the load is a photoconductor. The transmission mechanism has a coupling and
The image forming apparatus according to any one of claims 1 to 9, wherein the back crush is provided on the coupling. With the motor
When the rotor of the motor is rotating in the first direction, the driving force of the motor is transmitted to the first load, and when the rotor is rotating in the second direction opposite to the first direction, the above. A transmission mechanism that transmits the driving force of the motor to a second load different from the first load,
A control means for controlling the motor and
With
If the control means for rotating the rotor in the first direction fails, the control means controls the rotor to rotate in the second direction, and the control for rotating the rotor in the second direction fails. An image forming apparatus for determining whether or not the control for rotating the rotor in the first direction has failed due to a failure of the motor. The image forming apparatus according to claim 11, wherein the control means determines that the motor has failed when the control for rotating the rotor in the second direction fails. The image forming apparatus according to claim 12, wherein the control means determines that the failure of the first load occurs when the control for rotating the rotor in the second direction does not fail. The control means controls to rotate the rotor in the first direction at a rotation speed higher than the first predetermined speed, detects the rotation speed of the rotor, and the detected rotation speed of the rotor is the first predetermined speed. The image forming apparatus according to any one of claims 11 to 13, wherein if it is smaller, it is determined that the control for rotating the rotor in the first direction has failed. The control means controls to rotate the rotor in the second direction at a rotation speed higher than the second predetermined speed, detects the rotation speed of the rotor, and the detected rotation speed of the rotor is the second predetermined speed. The image forming apparatus according to any one of claims 11 to 14, wherein if it is smaller, it is determined that the control for rotating the rotor in the second direction has failed. The first load is the pressurizing roller of the fixing means having a heating roller and a pressurizing roller.
The second load is a contact separating means for setting the fixing means in a contact state in which the pressure roller is in contact with the heating roller or in a separation state in which the pressure roller is separated from the heating roller. The image forming apparatus according to any one of claims 11 to 15. Further, the fixing means is further provided with a detecting means for detecting whether the fixing means is in the contact state or the separated state.
If the control for rotating the rotor in the second direction does not fail and the state of the fixing means does not change, the control means determines that the first load and the second load have failed. The image forming apparatus according to claim 16. A motor control device that controls a motor configured to transmit driving force to a load by a transmission mechanism including backlash.
Means for rotating the rotor of the motor in the first direction to rotate the load, and
A means for determining whether the control for rotating the rotor in the first direction has failed, and
In response to the determination that the control for rotating the rotor in the first direction has failed, the motor is controlled to rotate the rotor in a second direction opposite to the first direction by a predetermined amount. A means for determining whether or not the control for rotating the rotor in the first direction has failed due to the failure of the rotor.
A motor control device equipped with. A motor control device that controls a motor configured to transmit a driving force to a first load and a second load by a transmission mechanism.
The transmission mechanism transmits the driving force to the first load when the rotor of the motor rotates in the first direction, and when the rotor rotates in the second direction opposite to the first direction, the driving force is transmitted. Is configured to be transmitted to the second load.
The motor control device is
Means for rotating the rotor in the first direction to rotate the first load, and
A means for determining whether the control for rotating the rotor in the first direction has failed, and
A means for controlling the rotation of the rotor in the second direction in response to the determination that the control for rotating the rotor in the first direction has failed.
A means for determining whether or not the control for rotating the rotor in the first direction has failed due to a failure of the motor by determining whether or not the control for rotating the rotor in the second direction has failed.
A motor control device equipped with. It is a method of controlling a motor by a motor control device.
The motor is configured to transmit the driving force to the load by a transmission mechanism including backlash.
The control method is
Rotating the rotor of the motor in the first direction to rotate the load,
Determining whether the control for rotating the rotor in the first direction has failed,
In response to the determination that the control for rotating the rotor in the first direction has failed, the motor is controlled to rotate the rotor in a second direction opposite to the first direction by a predetermined amount. To determine whether or not the control for rotating the rotor in the first direction has failed due to the failure of the rotor.
How to control the motor, including. It is a method of controlling a motor by a motor control device.
The motor is configured to transmit a driving force to a first load and a second load by a transmission mechanism.
The transmission mechanism transmits the driving force to the first load when the rotor of the motor rotates in the first direction, and when the rotor rotates in the second direction opposite to the first direction, the driving force is transmitted. Is configured to be transmitted to the second load.
The control method is
Rotating the rotor in the first direction to rotate the first load,
Determining whether the control for rotating the rotor in the first direction has failed,
In response to the determination that the control for rotating the rotor in the first direction has failed, the control for rotating the rotor in the second direction is performed.
By determining whether the control for rotating the rotor in the second direction has failed, it is determined whether or not the control for rotating the rotor in the first direction has failed due to the failure of the motor.
How to control the motor, including.

Images