JP5786283B2 - Motor control apparatus, image forming apparatus, and motor control method - Google Patents

Description

  The present invention relates to a motor control device that controls a stepping motor, an image forming apparatus having the motor control device, and a motor control method.

  In various apparatuses such as an image forming apparatus, a stepping motor is used, but the stepping motor may step out depending on conditions. Therefore, the conventional motor control device has been devised to suppress the occurrence of problems such as step-out.

  For example, Patent Document 1 describes that a back electromotive force is detected at the time of zero crossing of a motor driving current for the purpose of reducing noise and vibration, a step-out associated therewith, and improving current consumption efficiency. Specifically, in Patent Document 1, an A or B phase current detection unit is provided, and when a zero crossing of the output current is detected, the output is set to high impedance (hereinafter referred to as Hi-Z) and the back electromotive voltage is measured during that time. In addition, it is disclosed to detect whether or not the motor is rotating based on the presence or absence of a counter electromotive voltage, and to detect the rotation speed based on the amplitude value of the counter electromotive voltage.

  However, in the technique described in Patent Document 1, in order to measure the back electromotive force during the rotation of the motor, the zero cross point of the output current is detected and the output is forcibly set to Hi-Z for a certain period. A complex control system is required to do this.

  The present invention has been made to solve this problem in view of the above circumstances, and can measure the counter electromotive force of a rotating motor with a simple configuration and suppress the occurrence of motor step-out. It is an object to provide a control device, an image forming apparatus, and a motor control method.

  The present invention employs the following configuration in order to achieve the above object.

The present invention has a plurality of coils, sequentially applies a voltage to the plurality of coils, and when a voltage is applied to any one of the plurality of coils, at least one of the other coils. Is a motor control device for controlling a stepping motor whose rotor rotates under control including a state in which no voltage is applied, the voltage detecting means for detecting a voltage between at least one of the plurality of coils, and the stepping motor the basis of the voltage between the primary coil when the voltage applied to the primary coil during rotation control becomes open, and determining means for determining a condition related to loss of synchronism of the stepping motor, the determination Setting changing means for changing the setting of the current value supplied to the stepping motor based on the determination result by the means;
Analyzing means for analyzing a margin until the stepping motor is in a state immediately before step-out .

  The motor control device according to the present invention includes a setting change unit that changes a setting of a current value supplied to the stepping motor based on a determination result by the determination unit, and a step until the stepping motor is in a state immediately before the step-out. Analyzing means for analyzing the margin.

  Further, in the motor control device of the present invention, the determination means determines the state relating to the step out of the stepping motor based on a voltage value between the coils or a phase difference between the voltage between the one coil and the applied voltage. I do.

Further, the motor control device of the present invention is configured to set a threshold value of the voltage between the coils for determining a state related to the step-out of the stepping motor and the current value corresponding to the state determined based on the threshold value. And the determination unit refers to the threshold table to determine the state, and the setting change unit refers to the threshold table from the determination result by the determination unit. To set the current value.

In the motor control apparatus of the present invention, the voltage detection unit reverses the voltage between the one coil at a predetermined time in a period in which the applied voltage state detection unit detects the state of the applied voltage as an open state. Detecting as an electromotive voltage, the determination means determines a state related to the stepping motor step-out based on the counter electromotive voltage.

Further, in the motor control device of the present invention, the voltage detection means may be arranged between each of the one coils at a plurality of predetermined points in a period in which the applied voltage state is detected as an open state by the applied voltage state detection means. The voltage is detected, and the determination means determines an average value of the voltages between the plurality of coils detected at the plurality of time points as a counter electromotive voltage, and determines a state relating to the stepping motor step-out based on the counter electromotive voltage. To do.

The present invention has a plurality of coils, sequentially applies a voltage to the plurality of coils, and when a voltage is applied to any one of the plurality of coils, at least one of the other coils. Is an image forming apparatus having a motor control device that controls a stepping motor whose rotor rotates under control including a state in which no voltage is applied, wherein the motor control device is a voltage between at least one of the plurality of coils. And a step-out step of the stepping motor based on a voltage between the one coil when an applied voltage applied to the one coil is opened during rotation control of the stepping motor. determination means for determining the state relating to, based on a determination result by the determination means, setting to change the setting of the current value supplied to the stepping motor A changing means, analysis means for the stepping motor is to analyze the margin until the state of step-out immediately before the.

The present invention has a plurality of coils, sequentially applies a voltage to the plurality of coils, and when a voltage is applied to any one of the plurality of coils, at least one of the other coils. Is a motor control method for controlling a stepping motor in which a rotor rotates under control including a state in which no voltage is applied, the voltage detecting procedure for detecting a voltage between at least one of the plurality of coils, and the stepping motor the basis of the voltage between the primary coil when the applied voltage the applied to one coil in the rotation control becomes open, a determination procedure for determining the state related to loss of synchronism of the stepping motor, the determination A setting change procedure for changing the setting of the current value supplied to the stepping motor based on the determination result by the procedure;
And an analysis procedure for analyzing a margin until the stepping motor is in a state immediately before step-out .

  According to the present invention, the counter electromotive force of a rotating motor can be measured with a simple configuration, and the occurrence of motor step-out can be suppressed.

It is a figure explaining a motor control apparatus. It is a 1st figure explaining the motor of this embodiment. It is a 2nd figure explaining the motor of this embodiment. It is a figure explaining the phase relationship of an applied voltage and a counter electromotive voltage. It is a flowchart explaining operation | movement of the motor control apparatus of this embodiment. It is a figure which shows an example of a threshold value table. It is a 1st flowchart explaining the process which adjusts a setting electric current value with reference to a threshold value table. It is a 2nd flowchart explaining the process which adjusts a setting electric current value with reference to a threshold value table.

  In the present invention, when the applied voltage applied to the motor is in an open state, the voltage between the coils of the motor is detected as a counter electromotive voltage, and the margin to the motor step-out is determined based on the counter electromotive voltage. To analyze.

(Embodiment)
Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 is a diagram illustrating a motor control device.

  The motor control apparatus 100 according to the present embodiment includes a motor 110, a CPU (Central Processing Unit) 120, a ROM (Read Only Member) 130, and a motor driver 140. The CPU 120 and the motor driver 140 control driving of the motor 110. In the present embodiment, the motor 110 is described as being included in the motor control device 100, but the motor 110 may be provided outside the motor control device 100. In this case, the motor control device 100 includes a CPU 120, a ROM 130, and a motor driver 140.

  The motor 110 of this embodiment is a two-phase stepping motor. Details of the motor 110 will be described later.

  The CPU 110 according to the present embodiment outputs a control signal for driving the motor 110 to the motor driver 140. Details of the CPU 120 will be described later. In this embodiment, the motor driver 140 is a clock-in type motor driver. The clock-in method is a method in which the motor driver generates a drive signal for driving the stepping motor based on a control signal (clock signal) from the CPU, and drives the stepping motor. Therefore, in the present embodiment, a drive signal that the motor driver 140 supplies to the motor 110 is generated based on the control signal generated by the CPU 110. A drive signal supplied from the motor driver 140 to the motor 110 is an applied voltage described later.

  The ROM 130 stores a pulse rate table 131. The pulse rate table is a table that stores frequencies for rotating the motor 110 at a specified speed in accordance with each excitation method.

  The motor driver 140 outputs a voltage applied to the motor 110 in accordance with a control signal from the CPU 120.

  Next, details of the CPU 120 of this embodiment will be described. The CPU 120 of this embodiment includes an output signal generation unit 150 and a comparison control unit 160.

  The output signal generation unit 150 generates a signal to be output to the motor driver 140 in order to control the motor 110. The output signal generation unit 150 of this embodiment includes a rotation direction signal output unit 151, an excitation method signal output unit 152, a pulse rate signal output unit 153, and a set current signal output unit 154.

  The rotation direction signal output unit 151 outputs a rotation direction signal according to the specifications of the motor driver 140. The excitation method signal output unit 152 outputs an excitation method signal for designating the excitation method to the motor 110 in accordance with the specifications of the motor driver 140. Examples of the excitation method include one-phase excitation, two-phase excitation, and 1-2 phase excitation.

  The pulse rate signal output unit 153 outputs a frequency signal according to the excitation method designated by the excitation method signal and the pulse rate table 131. The set current signal output unit 154 sets a current value for outputting torque for driving the motor 110. The set current signal output unit 154 of the present embodiment can change the setting of the current value and adjust the current supplied to the motor 110 based on the comparison result by the comparison control unit 160 described later.

  The comparison control unit 160 is a state of an applied voltage output from the motor driver 140 to the motor 110 from each signal output from the rotation direction signal output unit 151, the excitation method signal output unit 152, and the pulse rate signal output unit 153. Is detected. Further, the comparison control unit 160 takes in the inter-coil voltage signal 161 indicating the inter-coil voltage of the motor 110.

  In this embodiment, when an applied voltage is supplied to the motor 110 and the motor 110 is rotating, the inter-coil voltage signal 161 is combined with not only the applied voltage but also a counter electromotive voltage generated by the motor 110 rotating. Signal. Therefore, when the applied voltage is in the open state, the signal that appears between the coil voltage signals 161 is a counter electromotive voltage.

  In the comparison control unit 160 of the present embodiment, the phase difference between the applied voltage and the counter electromotive voltage is estimated from the inter-coil voltage signal 161 when the applied voltage is in the open state, that is, the counter electromotive voltage. Details will be described later with reference to FIG.

  Next, the motor 110 will be described with reference to FIGS. FIG. 2 is a first diagram illustrating the motor according to the present embodiment. FIG. 2A is a diagram illustrating a bipolar stepping motor, and FIG. 2B is a diagram illustrating a unipolar motor.

  In the present embodiment, the bipolar stepping motor of FIG. 2A is the motor 110, but the unipolar stepping motor shown in FIG. 2B can also be applied to the motor 110 of the present embodiment.

  As shown in FIG. 2A, the motor 110 of this embodiment includes a roller 111 and coils 112 and 113. FIG. 2A shows the positional relationship between the A phase and AB phase of the rotor 111 and the coil 112, and the B phase and BB phase of the coil 113.

  The direction of the current flowing through the coils 112 and 113 is a combination of A phase-AB phase or AB phase-A phase in the coil 112 and B phase-BB phase or BB phase-B phase in the coil 113.

  The unipolar motor 110A shown in FIG. 2B also includes a rotor 111A and coils 112A and 113A. The directions of the currents flowing through the coils 112A and 113A are the AB phase-A phase of the bipolar motor 110 from the COM phase of the coil 112A, and the A phase-AB phase of the bipolar motor 110 from the COM phase of the coil 112A to the B phase. Corresponding to The relationship between the B phase, BB phase, and COM of the coil 113A is the same.

  In the case of the motor 110 shown in FIG. 2A, the inter-coil voltage can be obtained by the A phase voltage value−the AB phase voltage value. In the case of the unipolar shown in FIG. 2B, the inter-coil voltage can be obtained by COM voltage value−A phase voltage value or COM voltage value−AB phase voltage value.

  Next, switching in the motor 110 will be described with reference to FIG. FIG. 3 is a second diagram illustrating the motor according to the present embodiment.

  3A is a diagram simply illustrating a switching unit of a bridge circuit included in the motor driver 140, and FIG. 3B is a diagram illustrating a torque vector in 1-2 phase excitation. (C) is a figure which shows the switching sequence by 1-2 phase excitation.

For example, when the transistor Tr1 and the transistor Tr4 are turned on as shown in the switching sequence state (1) shown in FIG. 3C, a current flows from the A phase to the AB phase of the coil 112 of the motor 110. During this time, no current flows between the B phase and the BB phase of the coil 113.
Further, as shown in the state (2) of the switching sequence, when the transistors Tr1, Tr4, Tr5, Tr8 are turned on, current flows in the A phase-AB phase of the coil 112 and the B phase-BB phase of the coil 113.

  Here, in the state (1) of the switching sequence, the transistors Tr5, Tr6, Tr7, Tr8 are off, and no current flows between the B phase and the BB phase of the coil 113, and the applied voltage state to the coil 113 Is open. Since the motor 110 is rotating at this time, the voltage detected between the B phase and the BB phase of the coil 113 in the state (1) is the counter electromotive voltage of the motor 110.

  In the coil 112, when the transistors Tr1, Tr2, Tr3, Tr4 are turned off, the phase A and the phase AB are opened. In the coil 113, when the transistors Tr5, Tr6, Tr7, and Tr8 are off, the phase between the B phase and the BB phase is opened. Therefore, as shown in FIG. 3C, in the case of the states (1) and (5), the phase between the B phase and the BB phase is opened, and in the case of the states (3) and (7), between the A phase and the AB phase. Becomes an open state.

  The comparison control unit 160 of the present embodiment detects when the applied voltage is in an open state from the inter-coil voltage signal 161, and measures the inter-coil voltage, that is, the back electromotive voltage at that time.

  The phase relationship between the applied voltage and the counter electromotive voltage will be described below. FIG. 4 is a diagram for explaining the phase relationship between the applied voltage and the counter electromotive voltage. FIG. 4 shows a simulation result when the load torque of the motor 110 is increased by 1-2 phase excitation.

  In FIG. 4, a solid line A indicates a waveform of an applied voltage between the A phase and the AB phase (or B phase and BB phase) in 1-2 phase excitation.

  When the applied voltage is positive, the current is flowing from the A phase to the AB phase. When the applied voltage is negative, the current is flowing from the AB phase to the A phase. When the applied voltage is 0V Is an open state where no applied voltage is applied.

  The other three sine waves are waveforms indicating the back electromotive force generated between the A phase and the AB phase (or B phase and BB phase) according to the magnitude of the load torque of the motor 110. Waveform B shows the counter electromotive voltage when the load torque is large, and waveform C shows the counter electromotive voltage when the load torque is small. Waveform D shows the back electromotive force when the load torque is between the load torque shown in waveform B and the load torque shown in waveform C.

  From the results shown in FIG. 4, it can be seen that the phase of the back electromotive force with respect to the applied voltage is delayed as the load torque increases.

  In FIG. 4, the waveform detected between the A phase and the AB phase (or the B phase and the BB phase) when the applied voltage is other than the open state is a voltage waveform obtained by adding the applied voltage and the counter electromotive voltage. However, since the applied voltage is 0 V when the applied voltage is in an open state, the waveform detected between the A phase and the AB phase (or the B phase and the BB phase) is a waveform of only the back electromotive voltage.

  As described above, the phase of the counter electromotive voltage varies depending on the magnitude of the load torque, but it is difficult to directly see the phase difference between the applied voltage and the counter electromotive voltage. However, in the simulation result of FIG. 4, if the voltage between the A phase and the AB phase (or B phase and BB phase) is detected in the open state of the applied voltage, the phase difference between the applied voltage and the counter electromotive voltage can be estimated. I understand that I can do it.

  For example, the voltage between the A phase and the AB phase (or B phase-BB phase) at the measurement point that is in the open state while the applied voltage is changed from positive to negative is about 2.0 V in the waveform B when the load torque is large. Detected. In the waveform C where the load torque is small, the voltage between the AB phase (or B phase and BB phase) is detected as about 0V. Further, in the waveform D where the load torque is medium, the voltage between the AB phase (or B phase and BB phase) is detected as about 1.2V.

  In this embodiment, the timing for measuring the voltage between the A phase and the AB phase (or the B phase and the BB phase) is, for example, from the falling edge where the applied voltage is +3 V to 0 V in waveform A, and from the falling edge where the applied voltage is 0 V to -3 V Done between edges. The timing for measuring the voltage between the A phase and the AB phase (or the B phase and the BB phase) is a detection timing for detecting the back electromotive voltage.

  Further, the detection timing of the back electromotive force voltage may be between the rising edge where the applied voltage is -3 V to 0 V and the rising edge where the applied voltage is 0 V to +3 V in the waveform A.

  In this embodiment, the counter electromotive voltage detection timing may be one point between the above-mentioned edges, or may be an average value obtained by detecting the counter electromotive voltage a plurality of times between the edges.

  The detection of the counter electromotive voltage in this embodiment will be described below with reference to FIG. FIG. 5 is a flowchart for explaining the operation of the motor control device of the present embodiment.

  In the motor control apparatus 100 of the present embodiment, the comparison control unit 160 detects a back electromotive voltage, and determines whether or not the motor 110 is just before step-out based on the detected back electromotive voltage. When the motor 110 is just before stepping out, the comparison control unit 160 changes the setting current signal output from the setting current signal output unit 154 so that the motor 110 does not step out.

  The process within the dotted line I in FIG. 5 is a process for estimating the state of the applied voltage supplied from the motor driver 140 to the motor 110. The process within the dotted line II is a process for detecting the voltage between the coils of the motor 110. The inter-coil voltage is a voltage between A phase and AB phase (or B phase and BB phase). The process within the dotted line III is a process for measuring the back electromotive force and changing the set current signal.

  First, processing in the dotted line I will be described. The comparison control unit 160 according to the present embodiment takes in the rotation direction signal output from the rotation direction signal output unit 151 of the output signal generation unit 150 (step S501). Next, the comparison control unit 160 takes in the excitation method signal output from the excitation method signal output unit 152 (step S502). Next, the comparison control unit 100 takes in the pulse rate signal output from the pulse rate signal output unit 153 (step S503). Next, the ratio control unit 160 determines whether or not the excitation method of the motor 110 is the two-phase excitation method from the excitation method signal acquired in step S502 (step S504).

  In step S504, when the excitation method is the two-phase excitation method, the comparison control unit 160 ends the process. In the two-phase excitation method, an applied voltage is always applied between the A phase and the AB phase and between the B phase and the BB phase, and the applied voltage does not become an open state. It is not possible.

  In step S504, when the excitation method is not the two-phase excitation method (in the case of the 1-2 phase excitation method), the comparison control unit 160 uses the rotation direction signal and the pulse rate signal and from the motor driver 140 to the motor 110 at that time. The state of the applied voltage supplied to is detected (step S505).

  Next, processing in the dotted line II when the excitation method is not confirmed will be described. The comparison control unit 160 takes in the inter-coil voltage signal 161 (step S506). The inter-coil voltage is a voltage between A phase and AB phase (or B phase and BB phase).

  In the following, processing within the dotted line III in FIG. 5 will be described. When it is detected in step S505 that the state of the applied voltage is an open state, the comparison control unit 160 detects the voltage between the A phase and the AB phase (or the B phase and the BB phase) from the inter-coil voltage signal 161 (step S505). S507). The voltage between phase A and phase AB (or phase B and phase BB) detected in step S507 is a counter electromotive voltage because the applied voltage is 0V.

  Subsequently, the comparison control unit 160 detects a phase difference between the applied voltage and the counter electromotive voltage (step S508). Then, the comparison control unit 160 determines whether or not the motor 110 is immediately before step-out (step S509). In the present embodiment, a threshold table storing a phase difference for determining whether or not it is immediately before the step-out is set in advance and stored in a storage unit included in the motor control device 100. The comparison control unit 160 refers to the threshold value table and determines whether or not it is just before step-out. Details of the threshold value table will be described later.

  If it is determined in step S509 that it is immediately before the step-out, the comparison control unit 160 instructs the set current signal output unit 154 to increase the set current (step S510). When it is determined in step S509 that it is not immediately before the step-out, the comparison control unit 160 instructs the set current signal output unit 154 to decrease the set current (step S511).

  In the present embodiment, the set current value having an excessive margin can be avoided by the control in step S510 and step S511, and the occurrence of step-out can be avoided and the current consumption can be reduced. For example, if it is determined in step S509 that it is not immediately before the step-out and there is a sufficient margin before the step-out, the load torque is shifted to a medium state by adjusting the set current in a smaller direction. Let Thereby, current consumption can be reduced. The threshold regarding the margin until just before the step-out may be set in the threshold table. If it is determined in step S509 that it is just before the step-out, the load current is shifted to a medium state by adjusting the set current in the direction of increasing. Thereby, step-out can be prevented beforehand.

  In this embodiment, the phase difference between the applied voltage and the counter electromotive voltage is used to determine whether or not it is immediately before the step-out. However, the voltage value of the counter electromotive voltage when the applied voltage is in the open state is used. It may be determined whether or not it is just before step-out. Further, the comparison control unit 160 of the present embodiment may output a warning signal before adjusting the set current when it is determined that the step-out is just before in step S509.

  FIG. 6 is a diagram illustrating an example of the threshold value table. The threshold value table 60 shown in FIG. 6 is determined in advance at the design stage in consideration of the specifications of the motor control device 100 of the present embodiment and the characteristics of the motor 110.

  In this embodiment, in order to determine three states: a state immediately before step-out, a state in which there is no allowance until just before step-out, and a state in which there is allowance until just before step-out, The threshold value Vth1 and the second threshold value Vth2 were set.

  FIG. 7 is a first flowchart illustrating a process for adjusting the set current value with reference to the threshold value table. In the example of FIG. 7, the falling edge of the applied voltage is detected to detect the open state of the applied voltage.

  When the comparison control unit 160 detects an edge where the applied voltage is in an open state from plus to 0V, the comparison control unit 160 starts measuring the inter-coil voltage signal 161 and stores the measurement result data in a storage device (not shown) (step S701). Subsequently, when the comparison control unit 160 detects an edge that becomes negative from the open state where the applied voltage is 0 V, the measurement of the inter-coil voltage signal 161 is terminated (step S702). Note that the comparison control unit 160 of the present embodiment may have an ADC (analog to digital converter) (not shown) and measure the inter-coil voltage signal 161 by the ADC.

  Next, the comparison control unit 160 refers to the threshold value table 60, and compares the measured value (the value of the back electromotive voltage) at a predetermined point in time when the inter-coil voltage signal 161 is measured with the threshold value Vth1 and the threshold value Vth2. (Step S703). The predetermined time point is a time point set in advance.

  In step S703, when the value of the back electromotive voltage is equal to or greater than the threshold value Vth2 (step S704), the comparison control unit 160 determines that the load torque is large and the margin until step-out is small, that is, immediately before step-out. Adjustment to increase is performed (step S705).

  In step S703, when the value of the back electromotive voltage is less than the threshold value Vth2, the comparison control unit 160 determines whether or not the value of the back electromotive voltage is less than the threshold value Vth1 (step S706). If the value of the back electromotive voltage is less than the threshold value Vth1 in step S706, the comparison control unit 160 determines that the load torque is small and the margin until step-out is large, that is, there is a margin until the step-out direct theory is reached. Adjustment is made to reduce the current (step S707). When the value of the counter electromotive voltage is equal to or greater than the threshold value Vht1 in step S706, the value of the counter electromotive voltage is equal to or greater than the threshold value Vth1 and less than the threshold value Vth2. Therefore, the comparison control unit 160 determines that the margin until the load torque is medium and immediately before the step-out is appropriate, and does not adjust the set current (step S708).

  In FIG. 7, the counter electromotive voltage to be compared with the threshold values Vth1 and Vth2 is the counter electromotive voltage at a predetermined time point, but the present invention is not limited to this. In the present embodiment, the counter electromotive voltage compared with the threshold values Vth1 and Vth2 may be an average value of the counter electromotive voltage values at a plurality of time points.

  FIG. 8 is a second flowchart illustrating a process for adjusting the set current value with reference to the threshold value table. The flowchart of FIG. 8 shows processing in the case where the average value of the back electromotive force values at a plurality of time points is compared with the threshold values Vth1 and Vth2.

  Steps S801 and 802 in FIG. 8 are the same as steps S701 and 702 in FIG. The comparison control unit 160 extracts back electromotive voltage values at a plurality of time points from the time when the applied voltage is in an open state of 0 V, and compares the average value of these values with the threshold values Vth1 and Vth2 (step S803).

  The processing from step S804 to step S808 is the same as the processing from step S704 to step S708 in FIG.

  As described above, according to the present embodiment, the voltage between the coils of the motor 110 when the applied voltage supplied to the motor 110 is in the open state of 0 V is measured as the counter electromotive voltage, and this counter electromotive voltage is measured. Based on the above, it is determined whether or not the motor 110 is just before step-out. Therefore, according to the present embodiment, the conventional control for detecting the zero cross point of the output current and forcibly setting the output to Hi-Z for a certain period becomes unnecessary, and the counter electromotive voltage of the rotating motor with a simple configuration is eliminated. The occurrence of motor step-out can be suppressed.

  As mentioned above, although this invention has been demonstrated based on each embodiment, this invention is not limited to the requirements shown in the said embodiment. With respect to these points, the gist of the present invention can be changed without departing from the scope of the present invention, and can be appropriately determined according to the application form.

DESCRIPTION OF SYMBOLS 100 Motor control apparatus 110 Motor 120 CPU
130 ROM
140 Motor Driver 150 Output Signal Generation Unit 160 Comparison Control Unit

JP 2009-65806 A

Claims (9)

It has a plurality of coils, sequentially applies a voltage to the plurality of coils, and when a voltage is applied to any one of the plurality of coils, at least one of the other coils applies a voltage. A motor control device for controlling a stepping motor in which the rotor rotates under control including a state in which the rotor is not
Voltage detection means for detecting a voltage between at least one of the plurality of coils;
Determining means for determining a state relating to the step-out of the stepping motor based on a voltage between the one coil when an applied voltage applied to the one coil is in an open state during rotation control of the stepping motor; ,
Setting changing means for changing the setting of the current value supplied to the stepping motor based on the determination result by the determining means;
Analyzing means for analyzing a margin until the stepping motor is in a state immediately before step-out . The determination means includes
Wherein based on the phase difference between voltage and the voltage applied between the voltage value or the coil between the first coil, the motor control device according to claim 1, wherein performing the determination of the state related to loss of synchronism of the stepping motor. The determination means includes
Wherein based on the value of the voltage between the first coil, the motor control device according to claim 1, wherein performing the determination of the state related to loss of synchronism of the stepping motor. A threshold value table in which a threshold value of the voltage between the one coil for determining a state relating to the step-out of the stepping motor is associated with the setting of the current value corresponding to the state determined based on the threshold value; Have
The determination means includes
Judging the state with reference to the threshold table,
The setting change means includes
The motor control device according to claim 3 , wherein the current value is set by referring to the threshold value table from a determination result by the determination unit. The voltage detection means includes
The applied voltage state detecting means for detecting the open state of the applied voltage detects a voltage between the one coil at a predetermined time in a period in which the applied voltage state is detected as an open state, as a back electromotive voltage,
The determination means includes
The motor control device according to any one of claims 1 to 4 , wherein a state related to step-out of the stepping motor is determined based on the back electromotive voltage. The voltage detection means includes
Detecting a voltage between each of the one coils at a plurality of predetermined time points in a period in which the state of the applied voltage is detected as an open state by an applied voltage state detection unit that detects an open state of the applied voltage;
The determination means includes
The average value of the voltage between a plurality of said coils which is detected by the plurality of time points and the counter electromotive voltage, the any one of claims 1 to determine the state relating to loss of synchronism of the stepping motor based on the counter electromotive voltage 4 The motor control device according to item. The stepping motor, the motor control device according to any one of claims 1 to 6, characterized in that a motor 1-2 phase excitation. It has a plurality of coils, sequentially applies a voltage to the plurality of coils, and when a voltage is applied to any one of the plurality of coils, at least one of the other coils applies a voltage. An image forming apparatus having a motor control device that controls a stepping motor in which a rotor rotates by control including a state that is not performed,
The motor control device
Voltage detection means for detecting a voltage between at least one of the plurality of coils;
Determining means for determining a state relating to the step-out of the stepping motor based on a voltage between the one coil when an applied voltage applied to the one coil is in an open state during rotation control of the stepping motor; ,
Setting changing means for changing the setting of the current value supplied to the stepping motor based on the determination result by the determining means;
An image forming apparatus comprising: an analyzing unit that analyzes a margin until the stepping motor is in a state immediately before step-out . It has a plurality of coils, sequentially applies a voltage to the plurality of coils, and when a voltage is applied to any one of the plurality of coils, at least one of the other coils applies a voltage. A motor control method for controlling a stepping motor in which a rotor rotates with control including a state in which the rotor is not operated,
A voltage detection procedure for detecting a voltage between at least one of the plurality of coils;
A determination procedure for determining a state related to step-out of the stepping motor based on a voltage between the one coil when an applied voltage applied to the one coil is opened during rotation control of the stepping motor; ,
A setting change procedure for changing the setting of the current value supplied to the stepping motor based on the determination result by the determination procedure;
An analysis procedure for analyzing a margin until the stepping motor is in a state immediately before step-out .

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