JP2012120338A - Rotation control device of motor and method, and image forming apparatus using the same - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a rotation control device of a motor and a method using a PLL control capable of maintaining a rotation even when a clock is not input instantaneously, and an image forming apparatus using the same.SOLUTION: In a rotation control device of a motor in which a PLL control part 12 outputs a difference between a clock CK and a position detection signal St as a deviation signal Se and a control part 202 outputs a drive signal Sm generated by using the deviation signal and a phase detection signal Sf, the control part outputs a delay drive signal Smd where the drive signal is delayed when the deviation signal is input and outputs the drive signal without delay after a predetermined time has passed from a start of the output of the delay drive signal. Rotation speed of the motor is equal to or more than twice of the lowest rotation speed. The delay time is an integral multiple equal to or more than twice of a clock period corresponding to the rotation speed, and the predetermined time is equal to or less than the delay time. Thus, the rotation of the motor can be maintained even when the clock is not input instantaneously.

Description

  The present invention relates to a rotation control apparatus and method for a brushless motor using PLL control, and in particular, a rotation control apparatus and method for a brushless motor that can maintain rotation even when a clock is not input instantaneously, and The present invention relates to an image forming apparatus using the same.

  As one type of image processing apparatus that is an electronic device, an image forming apparatus (such as a copying machine, a facsimile machine, or a multifunction machine) that forms an image on recording paper is known. Various brushless motors such as a brushless motor for feeding recording paper and a motor for rotating a photosensitive drum are used in the image processing apparatus.

  In the control method of a conventional brushless motor (hereinafter also simply referred to as a motor), a frequency signal (for example, a pulse signal having a predetermined frequency for controlling the number of rotations of the motor) input from the control unit and a feedback from the motor encoder are fed back. Control is performed so that the rotation speed signals (signals from which actual rotation is detected) match. If the frequency signal and the rotation speed signal do not match, the device is stopped as an abnormal rotation of the motor.

  Patent Document 1 below discloses a method for controlling the rotation of a motor by a PLL control method. Specifically, as shown in FIG. 1, the controller 1 sends a driver 2 an operation control signal Sc such as start and stop, a reset signal Srs, and a rotation direction signal that designates a rotation direction (forward rotation or reverse rotation). Sw and a clock input pulse CK are transmitted. Based on these control signals, the driver 2 uses a position detection signal St from an encoder or the like attached to the air spindle 31 of the spindle unit 3 and a phase detection signal Sf from a hall sensor of the brushless motor 32. Then, drive control of the brushless motor 32 is performed, and rotation control of the air spindle 31 is performed.

  Referring to FIG. 2, the driver 2 includes an input / output unit 11, a PLL control unit 12, a control unit 13, a power unit 14, and an alarm generation unit 15. Control signals (operation control signal Sc, reset signal Srs, rotation direction signal Sw, and clock input pulse CK) from the controller 1 are input to the PLL control unit 12 via the input / output unit 11. The PLL control unit 12 generates a deviation signal Se from the deviation between the clock input pulse CK from the controller 1 and the position detection signal St from an encoder attached to the air spindle 31 in accordance with the operation control signal Sc. The PLL control unit 12 outputs the generated deviation signal Se together with the rotation direction signal Sw to the control unit 13.

  Based on the rotation direction signal Sw from the PLL control unit 12, the control unit 13 is based on the deviation signal Se from the PLL control unit 12 and the phase detection signal Sf from the hall sensor of the brushless motor 32. Drive signal Sm is generated and output to the power unit 14. Further, when the alarm signal Sr is input from the alarm generation unit 15, the control unit 13 stops the output of the drive signal Sm to the power unit 14 and outputs a reverse energization signal, and rapidly stops the rotation of the brushless motor 32. Let

  The power unit 14 generates a drive current Sa from the drive signal Sm and supplies it to the brushless motor 32. In addition, the power unit 14 detects an abnormal state such as overcurrent, overheating, or overspeed, and outputs an abnormal signal Sp to the alarm generation unit 15. The alarm generator 15 outputs an alarm signal Sr based on the abnormal signal Sp. The alarm signal Sr is output to an external device such as an alarm lamp, for example, and notifies the operator of the abnormality and is also output to the control unit 13.

  To explain the operation, when the motor 32 rotates, a start operation control signal Sc is output from the controller 1, and the PLL control unit 12 outputs a clock input pulse CK from the controller 1 and a position detection signal St from an encoder or the like. Based on the above, the deviation signal Se is generated. The control unit 13 generates a drive signal Sm based on the deviation signal Se, the phase detection signal Sf from the hall sensor, and the rotation direction signal Sw from the controller 1 input via the PLL control unit 12. The power unit 14 generates a drive current Sa from the input drive signal Sm and supplies it to the brushless motor 32. As a result, the motor rotates at a predetermined rotation speed.

  During the operation, when the power unit 14 detects overcurrent, overheating, over-rotation, or the like, the power unit 14 sends an abnormal signal Sp to the alarm generation unit 15. As a result, the alarm generation unit 15 outputs an alarm signal Sr to notify the abnormality. The alarm signal Sr is also input to the control unit 13, and the control unit 13 operates to send the drive signal Sm to the power unit 14 as a reverse energization signal, thereby stopping the brushless motor 32.

JP-A-7-31175

  When the clock input pulse CK input from the controller 1 to the brushless motor 32 is momentarily disturbed by a disturbance such as noise or static electricity, the clock input pulse CK may not be instantaneously input to the PLL controller 12. . This is not abnormal, and there is no problem even if the rotation of the motor is maintained. That is, when only one clock input pulse CK is not input and thereafter the clock input pulse CK is continuously input, there is no problem in maintaining the rotation of the motor. However, in the rotation control of the motor using the conventional PLL control shown in FIG. 2, since the position detection signal St from the motor is output and continuously supplied to the PLL control unit 12, the clock input pulse CK and the position detection are detected. There is a problem that the signal St is determined to be inconsistent and the device is forcibly stopped.

  FIG. 3A shows a case where the clock input pulse CK is normally input at a constant cycle. Since the clock input pulse CK and the position detection signal St are input to the PLL controller 12 at a constant cycle and the same timing, the deviation signal Se is not generated. Therefore, the drive signal Sm is generated at a constant period, and the abnormal signal Sp remains at a low level corresponding to the normal state.

  On the other hand, FIG. 3B shows a case where only one clock input pulse CK is not input to the PLL control unit 12 due to noise or static disturbance factors (the clock input pulse CK that is not input is indicated by a broken line). ). Even in this case, since the air spindle 32 rotates with inertia, the position detection signal St is input to the PLL controller 12 at a constant cycle. Therefore, the deviation signal Se is generated at the timing when the clock input pulse CK is not input. As a result, a drive signal Sm different from that during normal rotation is generated, and the abnormal signal Sp becomes a high level corresponding to the abnormal state. The abnormal signal Sp is input to the alarm generation unit 15, the alarm signal Sr is input to the control unit 13, the control unit 13 operates to send the drive signal Sm to the power unit 14 as a reverse energization signal, and the brushless motor 32 is activated. Stop.

  As described above, in the motor rotation control device using the conventional PLL control, the device is forcibly stopped even when the rotation of the motor is not hindered so that only one clock input pulse CK is not input. There is a problem that will be done.

  Therefore, the present invention provides a motor rotation control device capable of maintaining the rotation even when no clock is instantaneously input in the rotation control of the motor using the PLL control and suppressing an unnecessary stop. And a method, and an image forming apparatus using the same.

  The above object can be achieved by the following.

  That is, the motor rotation control device according to the present invention includes a PLL control unit and a control unit, and the PLL control unit represents a clock supplied in accordance with the rotation speed of the motor and a rotation position of the spindle rotated by the motor. The timing difference from the position detection signal is output to the control unit as a deviation signal, and the control unit generates a drive signal for driving the motor by using the deviation signal and the phase detection signal indicating the rotation phase of the motor. When the deviation signal is input, the control unit outputs to the motor a delayed drive signal obtained by delaying the drive signal by a predetermined delay time instead of the drive signal. The control unit does not delay the drive signal instead of the delay drive signal after a predetermined time has elapsed since the start of the output of the delayed drive signal. Output to the motor, the rotation speed of the motor is more than twice the minimum rotation speed that can be used, and the delay time is an integral multiple of the clock period corresponding to the rotation speed of the motor The predetermined time is a time equal to or shorter than the delay time.

  Preferably, the control unit stops the motor when the drive signal output without delay after a predetermined time has elapsed is abnormal.

  More preferably, the control unit generates a drive signal from the deviation signal and the phase detection signal, a delay unit that delays the drive signal by a delay time and outputs it as a delay drive signal, and an input delay drive A selector that outputs either a signal or an undelayed drive signal, a deviation signal determination unit that detects a deviation signal and outputs a first control signal, and a first control signal input from the deviation signal determination unit A counter that outputs a second control signal, and when the first control signal transits, the counter transits and outputs the second control signal, and starts a counting operation. The second control signal is shifted after counting, and the selector outputs a delay drive signal according to the transition of the second control signal when the first control signal transitions, and counts a predetermined time Depending on the transition of the second control signal, and outputs a drive signal which is not delayed.

  The motor rotation control method according to the present invention is a method for controlling the rotation of the motor by PLL control, and is a position detection signal representing the rotation position of the spindle rotated by the clock and the motor according to the rotation speed of the motor. A step of outputting the difference in timing as a deviation signal, a step of generating a drive signal for driving the motor from the deviation signal and a phase detection signal indicating the rotation phase of the motor, and outputting the drive signal to the motor, and a deviation signal Is output instead of the drive signal, a step of outputting a delay drive signal obtained by delaying the drive signal by a predetermined delay time to the motor, and after a predetermined time has elapsed since the start of the output of the delay drive signal And outputting the drive signal to the motor without delay instead of the delayed drive signal, and the use rotational speed of the motor is the lowest available rotation Every not less than 2 times, the delay time is more than twice the integer multiple of the time of the clock period corresponding to the operating rotation speed of the motor, the predetermined time is less time delay.

  An image forming apparatus according to the present invention includes the rotation control device for the motor described above and a motor controlled by the rotation control device.

  According to the present invention, the rotation of the motor can be maintained even when no clock is instantaneously input to the PLL control unit. Therefore, it is possible to prevent the device from being stopped unnecessarily even though the motor is normal, and the device can be used efficiently and economically without waste.

It is a block diagram which shows schematic structure of the rotation control apparatus of a motor. It is a block diagram which shows the internal structure of the conventional driver. 3 is a timing chart showing motor rotation control by the driver of FIG. 2. It is a block diagram which shows schematic structure of the rotation control apparatus of the motor which concerns on embodiment of this invention. It is a graph which shows the relationship between the electric current value of a motor, and a torque, and the relationship between the rotation speed of a motor, and a torque. It is a flowchart which shows operation | movement of the rotation control apparatus of the motor which concerns on this Embodiment. It is a timing chart which shows an example of the rotation control of the motor by the driver of FIG. It is a timing chart which shows another example of the rotation control of the motor by the driver of FIG.

  In the following embodiments, the same parts are denoted by the same reference numerals. Their names and functions are also the same. Therefore, detailed description thereof will not be repeated.

  Referring to FIG. 4, the motor rotation control device according to the embodiment of the present invention has the same configuration as that of FIG. 1 described above, and includes a controller 1 and a driver 200. The driver 200 includes an input / output unit 11, a PLL control unit 12, a control unit 202, a power unit 14, and an alarm generation unit 15. Since the driver 200 is different from that of FIG. 2 only in the control unit 202, the following description will mainly focus on the control unit 202.

  The control unit 202 includes a drive signal generation unit 204, a delay unit 206, a deviation signal determination unit 208, a counter 210, and a selector 212.

  The drive signal generation unit 204 has the same function as the control unit 13 of FIG. That is, the drive signal generation unit 204 is based on the deviation signal Se from the PLL control unit 12 and the phase detection signal Sf from the hall sensor of the brushless motor 32 based on the rotation direction signal Sw from the PLL control unit 12. Then, a drive signal Sm for the brushless motor 32 is generated and output to the power unit 14. In addition, when the alarm signal Sr is input from the alarm generation unit 15, the drive signal generation unit 204 stops outputting the drive signal Sm to the power unit 14 and outputs a reverse energization signal to rotate the brushless motor 32. Stop quickly.

  The delay unit 206 delays the drive signal Sm output from the drive signal generation unit 204 by a predetermined time and outputs the delayed drive signal Smd. For the delay unit 206, for example, a known delay circuit using a transistor can be used. Although details will be described later, the delay time is determined in relation to the cycle of the clock input pulse CK corresponding to the rotation speed of the motor.

  The deviation signal determination unit 208 detects the signal level of the input deviation signal Se and outputs a counter control signal Sct corresponding to the signal level of the deviation signal Se. For example, the deviation signal determination unit 208 outputs the counter control signal Sct at a low level if the input deviation signal Se is at a low level, and detects that the deviation signal Se has transitioned from a low level to a high level. The counter control signal Sct is changed from the low level to the high level.

  The counter 210 starts counting when the signal level of the input counter control signal Sct changes, and transitions the selector control signal SL when a predetermined time has elapsed. For example, if the counter control signal Sct is low level, the counter 210 outputs the selector control signal SL at low level, detects the rising edge of the counter control signal Sct, starts counting, and outputs the selector control signal SL. Launch. When the predetermined time has elapsed, the selector control signal SL is lowered. A known circuit that counts a predetermined time can be used as the counter 210.

  The selector 212 outputs either the input drive signal Sm or the delayed drive signal Smd as the final drive signal Smo according to the selector control signal SL. For example, the selector 212 outputs the drive signal Sm as the final drive signal Smo when the selector control signal SL is at the low level, and outputs the delayed drive signal Smd as the final drive signal Smo when the selector control signal SL is at the high level. . For the selector 212, a known circuit using a transistor gate can be used.

  In FIG. 4, the drive signal Sm is shown by one signal line, but a plurality of signals may be used. It is only necessary to supply the power unit with a number of signals corresponding to the circuit of the power unit that generates the drive current Sa (for example, three-phase current) for the brushless motor. If there are a plurality of signals, delay circuits and selectors corresponding to the number of signals are provided, and each drive signal and the corresponding delay drive signal may be alternatively output by the selector.

  The operation of the driver 200 configured as described above will be described below. As described above, the delay time of the delay unit 206 is determined in relation to the cycle of the clock input pulse CK corresponding to the rotation speed of the motor (more precisely, the rotation speed of the spindle unit where the motor rotates). In the present embodiment, the motor is used at a rotational speed that is twice or more the minimum rotational speed of the motor, and the delay time of the delay unit 206 is set to be equal to or less than the cycle of the clock input pulse CK corresponding to the minimum rotational speed of the motor. .

In a brushless motor, the rotational force and the rotational speed are determined by the amount of current flowing in the coil section and the strength of the magnetic field, and the rotational speed range in which the motor can be used is usually limited by the resistance of the rotating object (load). . FIG. 5 shows the result of measurement with a constant voltage of 24 V supplied to a brushless motor used in the image forming apparatus under the condition of 2700 revolutions per minute. In the graph of FIG. 5, the solid line indicates the relationship between the current I (A) supplied to the motor and the torque Trq (mNm) of the motor, and the broken line indicates the rotational speed of the motor (the number of revolutions per minute) N (min ^-1 ) and the motor torque Trq (mNm). In this case, if the load range to be used is 3 mNm to 120 mNm, the usable rotation speed range is 500 rpm to 2000 rpm.

  When the motor having the characteristics shown in FIG. 5 is a control target, the usable rotation speed is in the range of 500 rpm to 2000 rpm, and therefore, the rotation speed that is twice or more the minimum rotation speed is 1000 rpm or more. When the frequency of the clock input pulse CK for outputting the lower limit rotation speed 500 rpm and the upper limit rotation speed 2000 rpm of the usable rotation speed is 500 Hz and 2000 Hz, the delay time of the delay unit 206 corresponds to the minimum rotation speed (500 rpm). The period of the clock input pulse CK is 2 msec (500 Hz) or less. The period of the clock input pulse CK corresponding to the motor rotation speed of 1000 rpm is 1 msec.

  Hereinafter, the motor control operation by the driver 200 will be described with reference to the flowchart of FIG. Here, the motor to be controlled is a motor having the characteristics shown in FIG. 5, and the rotation speed used is 1000 rpm. The clock input pulse CK has a frequency of 1000 Hz and a period of 1 msec. The delay time Tm of the delay unit 206 is 2 msec.

  In step 300, electric power is supplied to the motor to start rotation of the motor. The electric power is supplied so that the rotation speed is 1000 rpm in consideration of the load. At this stage, PLL control is not performed.

  In step 302, the start operation control signal Sc, the rotation direction signal Sw, and the clock input pulse CK are supplied from the controller 1 to the PLL controller 12 in order to validate the PLL control. Specifically, as shown in FIG. 7, a clock input pulse CK having a period of 1 msec is input to the PLL control unit 12.

  In step 304, the PLL control unit 12 determines whether or not there is a difference in timing between the clock input pulse CK from the controller 1 and the position detection signal St from the encoder. If there is no difference, the process proceeds to step 306, and if there is a difference, the process proceeds to step 308.

  In step 306, since there is no difference in timing between the clock input pulse CK and the position detection signal St from the encoder, the deviation signal Se is not generated and constant speed control is continued. The fact that the deviation signal Se is not generated specifically means that the signal level of the deviation signal Se does not change. This corresponds to a period until immediately before time t1 in the timing chart of FIG. The deviation signal Se remains at the initial low level. In this state, the counter control signal Sct output from the deviation signal determination unit 208 remains at low level, the counter 210 does not operate, and the selector control signal SL remains at low level. Therefore, the final drive signal Smo (Smo in the leftmost period D1) output from the selector 212 is the same signal as the undelayed drive signal Sm (Sm in the period D1). As a result, the same drive signal as that in the prior art is input to the power unit 14.

  In step 308, since there is a difference in timing between the clock input pulse CK and the position detection signal St, the PLL control unit 12 outputs the deviation signal Se. That is, the deviation signal Se is generated and output as the difference between the clock input pulse CK and the position detection signal St. This corresponds to the fact that the deviation signal Se is output at a high level at time t1 in FIG.

  When the deviation signal Se is output at a high level, in step 310, the selector 212 is switched. Specifically, the deviation signal determination unit 208 detects the deviation signal Se that has transitioned to a high level, causes the counter control signal Sct to transition to a high level, and outputs it to the counter 210. In response to the transition of the counter control signal Sct to the high level, the counter 210 starts counting and simultaneously shifts and outputs the selector control signal SL to the high level. Accordingly, the selector 212 switches the input signal to be output as the output signal, and outputs the delayed drive signal Smd output from the delay unit 206 as the final drive signal Smo.

  In step 312, the counter 210 counts a predetermined time Tp, and in step 314, the counter 210 determines whether or not the predetermined time Tp has elapsed. The predetermined time Tp is the same as the delay time Tm and is 2 msec. If the predetermined time has not elapsed, the process returns to step 312 and continues counting until the predetermined time Tp elapses. When it is determined that the predetermined time Tp has elapsed, the process proceeds to step 316.

  The processes of steps 310, 312 and 314 are executed during times t1 to t3 in FIG. The drive signal Sm in this period (Sm in the period D2) is not a pulse waveform having a constant period (1 msec) because the deviation signal Se is output at a high level. However, the final drive signal Smo of the selector 212 is the delayed drive signal Smd of the period D1, that is, the drive signal Sm of the period D1. Accordingly, a normal drive signal with a constant period is input to the power unit 14 and the motor operates normally.

  In step 316, the counter 210 outputs a low-level selector control signal SL to switch the selector 212. Accordingly, the selector 212 switches the input signal to be output as the output signal, and outputs the undelayed drive signal Sm as the final drive signal Smo. This is a period after time t3 in FIG. The drive signal Sm returns to a normal pulse signal having a fixed period, and the normal drive signal Sm (Sm in the period D3) is output from the selector 212 as the final drive signal Smo (Smo in the period D3).

  In step 318, the power unit 14 determines whether or not the final drive signal Smo that is input is normal. If the final drive signal Smo is normal, the process proceeds to step 306, and constant speed control is continued. If the final drive signal Smo is not normal, the process proceeds to step 320, and the power unit 14 outputs the abnormal signal Sp. When the abnormal signal Sp is output, the alarm generation unit 15 outputs the alarm signal Sr. The alarm signal Sr is input to the drive signal generator 204, and the drive signal generator 204 stops outputting the drive signal Sm and outputs a reverse energization signal to stop the rotation of the brushless motor 32. In the example of FIG. 7, after t3, the normal drive signal Sm (Sm in the period D3) having a constant period is output as the final drive signal Smo from the selector 212 (Smo in the period D3), and the process proceeds to step 306. .

  As described above, when the clock input pulse CK is not instantaneously input to the PLL control unit 12, the drive signal Smd obtained by delaying the normal drive signal Sm is input to the power unit 14 as the final drive signal Smo. Therefore, the rotation of the motor can be maintained.

  On the other hand, in this embodiment, the motor is stopped when the clock input pulse CK is not continuously input to the PLL control unit 12 twice or more (see FIG. 8). Also in this case, control is performed according to the flowchart of FIG.

  In FIG. 8, the pulse sequence up to time t2 is the same as in FIG. However, in FIG. 8, since the clock input pulse CK is not input to the PLL controller 12 at times t2 and t3, the deviation signal Se (pulses P1 and P2) is generated. Therefore, the drive signal generation unit 204 generates the drive signal Sm using the rotation direction signal Sw, the deviation signal Se, and the phase detection signal Sf (periods D2 and D3 related to Sm).

  Until it is determined in step 314 that the predetermined time Tp has elapsed (until time t3), the delayed drive signal Smd is output from the selector 212 as the final drive signal Smo. Therefore, since the normal drive signal Sm having a constant period is supplied to the power unit 14, the motor maintains its rotation.

  In step 314, after it is determined that the predetermined time Tp has elapsed (after time t3), the non-delayed drive signal Sm is output from the selector 212 as the final drive signal Smo. At this time, the drive signal Sm output as the final drive signal Smo is not a normal pulse signal. Therefore, in step 320, the abnormal signal Sp is output at a high level (see FIG. 8). When the abnormal signal Sp is output, as described above, the alarm signal Sr output from the alarm generation unit 15 is input to the drive signal generation unit 204, and the drive signal generation unit 204 stops outputting the drive signal Sm. A reverse energization signal is output, and the rotation of the brushless motor 32 is stopped. In this way, the motor can be stopped in an obvious abnormal state where a plurality of clock input pulses CK are not continuously input to the PLL controller 12.

  As described above, when the clock input pulse CK is not continuously input to the PLL control unit 12 only once due to noise or the like (normal state), the motor is not stopped and unnecessary stop of the device is suppressed. be able to. Further, in an abnormal state where the clock input pulse CK is not continuously input to the PLL control unit 12, the motor can be stopped to ensure safety.

  In the above, the motor is used at a rotation speed of 1000 rpm, the cycle of the clock input pulse CK is 1 msec, the delay time Tm of the delay unit 206 is 2 msec, the predetermined time that the counter 210 counts (the time for outputting the delay drive signal Smd from the selector 212) ) Although the case where Tp is 2 msec has been described, the present invention is not limited to this. The use rotation speed of the motor may be at least twice the minimum rotation speed when the motor is stably used. The function of the delay unit 206 is to enable a normal driving signal Sm to be input to the power unit 14 for a predetermined time immediately after the clock input pulse CK is not input. May be a time that is n times (n is an integer of 2 or more) the period of the clock input pulse CK corresponding to the rotational speed of the motor. Since the predetermined time Tp counted by the counter 210 is a time for forcibly outputting the normal drive signal Sm, the predetermined time Tp may be a time equal to or shorter than the delay time Tm. For example, when the cycle of the clock input pulse CK is 0.5 msec (for example, the use frequency of the motor is 2000 rpm), Tm can be set to 1 msec and Tp can be set to 1 msec. In addition, when the cycle of the clock input pulse CK is 1 msec (the use frequency of the motor is 1000 rpm), Tm may be 3 msec and Tp may be 2 msec. Further, when the time that the drive signal Sm is affected by one deviation signal Se is relatively short, that is, when the deviation signal Se returns to a low level, the drive signal Sm returns to a normal signal in a relatively short time. Even if Tm is set to 2 msec (the period of the clock input pulse CK is 1 msec), Tp may be shorter than 2 msec.

  In the above description, the case where the output of the drive signal Sm is stopped and the motor is stopped by the alarm signal Sr output when the abnormal signal Sp is output has been described. However, depending on the use of the motor, the drive signal Sm It is not necessary to stop the output. For example, in a drum motor for a copying machine, even if the rotational speed is slightly changed, the image on the drum surface is displaced and cannot be used. Therefore, it is necessary to stop the motor. However, if it is a paper feeding motor, the rotational speed may be adjusted without stopping the motor. In this case, the drive signal generator maintains the output of the drive signal Sm.

  The transition direction of the control signal described above may be reversed. For example, the deviation signal Se may be at a high level when there is no difference between the clock input pulse CK and the position detection signal St, and may transition to a low level when there is a difference. The selector control signal SL may be at a high level until the deviation signal Se is detected, and may transition to a low level when the deviation signal Se is detected. In this case, the counter 210 changes the selector control signal SL to a high level after a predetermined time Tp has elapsed. The selector 212 may output the non-delayed drive signal Sm if the selector control signal SL is high level, and may output the delayed drive signal Smd if it is low level.

  Although the case where the counter 210 switches the selector 212 has been described above, the deviation signal determination unit 208 may be configured to output a selector control signal SL for switching the selector 212. In this case, when the deviation signal determination unit detects the deviation signal Se, the deviation signal Se transitions the selector control signal SL and starts the count operation of the counter by the counter control signal Sct. Thereafter, when the deviation signal determination unit receives a signal notifying that the predetermined time has elapsed from the counter, the deviation signal determination unit transitions the selector control signal SL to the original level.

  The delay unit 206 may be realized using a memory instead of a known delay circuit. That is, the input signal may be temporarily stored as a digital signal and output after a predetermined time.

  The present invention has been described above by describing the embodiment. However, the above-described embodiment is an exemplification, and the present invention is not limited to the above-described embodiment, and is implemented with various modifications. be able to.

DESCRIPTION OF SYMBOLS 1 Controller 3 Spindle part 31 Air spindle 32 Brushless motor 11 Input / output part 12 PLL control part 14 Power part 15 Alarm generation part 200 Driver 202 Control part 204 Drive signal generation part 206 Delay part 208 Deviation signal judgment part 210 Counter 212 Selector

Claims (5)

Including a PLL control unit and a control unit,
The PLL control unit outputs, as a deviation signal, a timing difference between a clock supplied in accordance with a use rotational speed of the motor and a position detection signal indicating a rotation position of a spindle rotated by the motor, to the control unit,
The control unit is a motor rotation control device that generates a drive signal for driving the motor based on the deviation signal and a phase detection signal representing a rotation phase of the motor, and outputs the drive signal to the motor,
When the deviation signal is input, the control unit, instead of the drive signal, outputs a delay drive signal obtained by delaying the drive signal by a predetermined delay time to the motor,
The control unit, after a predetermined time has elapsed since the start of the output of the delay drive signal, instead of the delay drive signal, outputs the drive signal to the motor without delaying,
The used rotational speed of the motor is at least twice the minimum usable rotational speed,
The delay time is a time that is an integer multiple of at least twice the clock period corresponding to the used rotational speed of the motor,
The motor rotation control device according to claim 1, wherein the predetermined time is equal to or shorter than the delay time.   2. The motor rotation control device according to claim 1, wherein the control unit stops the motor when the drive signal output without delay after the predetermined time has elapsed is abnormal. 3. The control unit
A drive signal generator for generating the drive signal from the deviation signal and the phase detection signal;
A delay unit for delaying the drive signal by the delay time and outputting the delayed drive signal;
A selector that outputs either the delayed drive signal that is input or the drive signal that is not delayed;
A deviation signal determination unit that detects the deviation signal and outputs a first control signal;
A counter that outputs a second control signal in response to the first control signal input from the deviation signal determination unit,
When the first control signal transits, the counter transits and outputs the second control signal, and starts a counting operation,
The counter transits the second control signal after counting the predetermined time,
The selector outputs the delay drive signal in response to the transition of the second control signal when the first control signal transitions, and responds to the transition of the second control signal after counting the predetermined time The motor rotation control device according to claim 1, wherein the drive signal that is not delayed is output. A method of controlling rotation of a motor by PLL control,
Outputting as a deviation signal a timing difference between a clock corresponding to the rotational speed of use of the motor and a position detection signal representing the rotational position of the spindle rotated by the motor;
Generating a drive signal for driving the motor based on the deviation signal and a phase detection signal representing a rotation phase of the motor, and outputting the drive signal to the motor;
When the deviation signal is output, instead of the drive signal, outputting a delayed drive signal obtained by delaying the drive signal by a predetermined delay time to the motor;
After a predetermined time has elapsed since the start of the output of the delayed drive signal, the output of the drive signal to the motor without delay instead of the delayed drive signal,
The used rotational speed of the motor is at least twice the minimum usable rotational speed,
The delay time is a time that is an integer multiple of at least twice the clock period corresponding to the used rotational speed of the motor,
The motor rotation control method, wherein the predetermined time is a time equal to or shorter than the delay time. The motor rotation control device according to any one of claims 1 to 3,
An image forming apparatus comprising: a motor controlled by the rotation control device.

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