JP2006301439A - Motor controller - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a motor controller capable of precisely stopping a motor with a low cost constitution. <P>SOLUTION: The motor controller which controls the rotation and stopping of the motor according to a motor control signal detects a first time T11 that is required by a sensor to detect one rotation of an eccentric cam (SP1 to SP4) by a motor remote signal when the DC motor is continuously rotated, detects a second time T12 that is required by the sensor to detect one rotation of the eccentric cam (SP5 to SP9) when the motor is rotated and stopped repeatedly a plurality of times, calculates the mean value of the inertia time ΔT from the time when the stopping of the DC motor is commanded by the motor remote signal to the time when the stopping of the motor is detected (step SP10), and corrects timing when the stopping of the DC motor is output by the motor remote signal (SP11). <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a motor control device, for example, a motor control device that controls a motor that lifts and lowers an intermediate belt separation mechanism in a tandem type color copying machine.

  FIG. 4 is a diagram showing a state at the time of four-color printing and monochrome printing by a color copying machine as an example of a conventional quadruple tandem type color image forming apparatus.

  As shown in FIG. 4A, the color image forming apparatus 10 includes four photosensitive drums 11a, 11b, 11c, and 11d that form images using magenta, cyan, yellow, and black toners, and four of them. The image forming unit includes four image forming units including transfer brushes 12a to 12d that face the photosensitive drums 11a to 11d, respectively. Transfer images (not shown) are sequentially conveyed from the photosensitive drum 11a to the photosensitive drum 11d by the transfer belt 13 that rotates counterclockwise in the four image forming units.

  The transfer belt 13 is wound around a driving roller 14, a driven roller 15, an auxiliary roller 16, a tension roller 17, and four backup rollers 18a to 18d. The backup rollers 18a to 18d are provided on the upstream side of the transfer brushes 12a to 12d, respectively, and the transfer belt 13 is in close contact with the photosensitive drums 11a to 11d, respectively. The tension roller 17 is urged to apply tension to the transfer belt 13 by a spring (not shown).

  The backup rollers 18a to 18d and the transfer brushes 12a to 12d are attached to an arm 20 that constitutes a belt separation mechanism, and the arm 20 is supported so as to be swingable about a rotation shaft of the backup roller 18d. In the vicinity of the upstream end portion of the arm 20, one end of the elevating arm 21 is rotatably attached. A lifting mechanism 30 is provided at the other end of the lifting arm 21.

  The elevating mechanism 30 raises the elevating arm 21 when printing a color image, and causes the four photosensitive drums 11a, 11b, 11c, and 11d to be in close contact with the transfer belt 13 by the arm 20. As shown in FIG. 4 (B), the elevating arm 21 is lowered. For this purpose, the arm 20 is pulled down around the rotation axis of the backup roller 18d, and only the photosensitive drum 18d that forms an image of black toner is brought into close contact with the transfer belt 13, so that toner other than black is used. The photosensitive drums 11 a to 11 c that form the image are separated from the transfer belt 13.

  The belt separation mechanism is provided in this way because, when an image is formed using only black toner, if the photosensitive drums 11a, 11b, and 11c in charge of toner other than black are kept in close contact with the transfer belt 13, the transfer belt is provided. This is because there is a problem that the image 13 is soiled or the image formed with the black toner is disturbed.

  FIG. 5 is a view showing the lifting mechanism shown in FIG. 4, and FIG. 6 is a view showing the configuration of the cam shown in FIG.

  The lifting mechanism 30 moves the lifting arm 21 up and down along the guide 31. A wide portion 22 having a wide bottom surface is provided at the lower end of the elevating arm 21, and the eccentric cam 32 abuts on the lower surface of the wide portion 22. The eccentric cam 32 is attached to a rotary shaft 33 that is driven by a reduction speed of a DC motor (not shown) being reduced by a speed reduction mechanism (not shown), and a sensor shielding plate 34 is attached to the rotary shaft 33. The sensor 40 is configured by arranging a light emitting diode and a photo sensor so as to face each other through a groove. As shown in FIG. 6, the eccentric cam 32 rotates in the clockwise direction, so that the light emitting diode and the photo sensor are aligned. When the sensor shielding plate 34 passes through the groove between them, the light reaching the photosensor from the light emitting diode is blocked, and this is detected and a sensor shielding signal is output.

  FIG. 7 is a timing chart showing the operation of the lifting mechanism. The operation of the lifting mechanism 30 shown in FIG. 5 will be described with reference to FIG. When the power is turned on, a motor remote signal for commanding rotation and stop of the DC motor is turned on by a control circuit (not shown) as shown in FIG. As a result, a DC voltage is supplied to the DC motor as shown in FIG. 7C, and the DC motor starts rotating. As the rotating shaft 33 is rotated by the rotation of the DC motor and the eccentric cam 32 is rotated once, the lifting mechanism 30 is reciprocated once as shown in FIG. When the eccentric cam 32 rotates once, the sensor shielding plate 34 also rotates once, and when the sensor shielding plate 34 passes through the groove of the sensor 40, a sensor that is turned on in a pulsed manner as shown in FIG. A shielding signal is output. A time T1 from when the sensor shielding plate 34 passes through the groove of the sensor 40 until the next passage through the groove is measured.

  Next, a time T2 from when the sensor shielding plate 34 passes through the groove of the sensor 40 until the motor remote signal is turned off is obtained. This time T2 corresponds to the rotation angle from the sensor shielding plate 34 when the elevating mechanism 30 is raised and stopped at the maximum ascending position. This time T2 is obtained by T1 × θ1 / 360 °. As shown in FIG. 6, the angle θ <b> 1 is a rotation angle of the eccentric cam 32 corresponding to the lowest position when the lifting mechanism 30 is lifted from the maximum rising position when the lifting mechanism 30 is lowered. When the time T2 elapses, the operation of the DC motor is stopped by turning off the motor remote signal as shown in FIG.

  However, since the belt separation mechanism is not a main part of the color image forming apparatus 10, an inexpensive DC motor or the like is used to reduce the cost, and there is a problem that the accuracy of the stop position of the DC motor is poor. That is, even if the motor remote signal is turned off at the timing when the time T2 has elapsed, the DC motor does not stop immediately but stops due to inertia and stops after the time Δt1 has elapsed.

  When descending, the motor remote signal is turned on, waits for the stop position time, and the motor remote signal is turned off after the elapse of time T3. This time T3 is obtained by T1 × (θ1−θ2) / 360 °. As shown in FIG. 6, θ2 is the rotation angle of the eccentric cam 32 corresponding to the descending and reaching the lowest position after the elevating mechanism 30 starts to rise. Even during the descending operation, the DC motor stops after the elapse of time Δt2 due to inertia. These times Δt1 and Δt2 vary, and this variation is a problem.

  Japanese Patent Laid-Open No. 6-255835 (Patent Document 1) describes that in a document feeder, a document stop position is accurately localized using a counter unit, a brake, and a conveyance clutch.

In Japanese Patent Laid-Open No. 10-17203 (Patent Document 2), when the detection sensor starts measuring the rising time during the ascending operation in the large-volume sheet feeding device, it is determined in consideration of variations such as the motor rotation speed and voltage. The preliminary time is added to this time and set as an abnormality detection time, and if the sensor does not turn on after this time, it is described that an abnormality is determined.
JP-A-6-255835 (paragraph number 0027, FIG. 6) JP-A-10-17203 (paragraph numbers 0011 to 0015, FIG. 9)

  If the lifting mechanism 30 is configured using a brake mechanism or the like as described in Patent Document 1, it can be stopped at a predetermined position. However, when conditions such as a system load change, the set position is changed. Not being able to stop, the situation where the specifications of the DC motor must be changed occurs, and not only the structure becomes complicated to provide a transport clutch and a brake mechanism, but also the cost increases.

  In the case of adding the preliminary time described in Patent Document 2, since the maximum value of the variation is set as the preliminary time, it is not necessarily applicable when stopping at a predetermined position.

  SUMMARY OF THE INVENTION An object of the present invention is to provide a motor control device that can be stopped at a predetermined position with a simple structure and accuracy even with an inexpensive motor.

  The present invention relates to a motor control device that controls rotation and stop of a motor, and includes a stop detection means for detecting stop of the motor, a motor rotation command signal to rotate the motor, and a motor stop command signal to be output. And a control unit that detects a deviation time from when the stop detection unit detects that the motor has stopped, and corrects the timing for outputting the motor stop command signal by the deviation time.

  According to the present invention, a motor control device that controls rotation and stop of a motor, the stop detection means for detecting the stop of the motor, the signal output means for outputting a rotation and stop command signal of the motor, and the signal output means are rotated. A deviation detection means for detecting a deviation time from the output of the command signal to rotate the motor and the output of the stop command signal until the stop detection means detects the stop of the motor, and the signal output means is a stop command signal And a control means for controlling to output the output timing earlier by the shift time.

  Preferably, the motor includes rotation detection means for detecting rotation of the motor and a cam member to which the rotation speed of the motor is transmitted, and the signal output means stops the motor until the rotation detection means detects one rotation of the cam member. In addition to outputting a command signal, the rotation detection signal is output in response to the stop detection means detecting the stop of the motor, and the deviation detection means is a first time required for one rotation of the cam member detected by the rotation detection means. And a deviation time is calculated based on a difference between the second time required for one rotation of the cam member when the motor is stopped and rotated again during one rotation of the cam member.

  Preferably, the signal output means repeatedly outputs a stop command signal and a rotation command signal a plurality of times during one rotation of the cam member, and the deviation detection means calculates a difference between the first time and the second time. Divide by times to calculate the average deviation time.

  Preferably, the signal output means repeatedly outputs a stop command signal and a rotation command signal a plurality of times during one rotation of the cam member, and the shift detection means outputs the stop command signal to the stop detection means so that the motor stops. The average of the deviation time is calculated by dividing the total of the respective times until detection of the number of times by multiple times.

  According to the present invention, the motor rotation command signal is output to rotate the motor, the deviation time from when the motor stop command signal is output until the stop detection means detects the motor stop is detected. Since the output timing of the motor is corrected by the shift time, even an inexpensive motor can be stopped with high accuracy.

  FIG. 1 is a block diagram of a motor control device according to an embodiment of the present invention. In FIG. 1, a control unit 1 controls a motor remote signal supplied to a DC motor 3, and the motor remote signal is given to a remote input terminal of the DC motor 3 via a driver 2. In the motor remote signal, “ON” is a motor rotation command signal, and “OFF” is a motor stop command signal. A signal current for detecting the stop of the DC motor 3 is output from the remote output end of the DC motor 3. This signal current flows through the resistor R1 and is converted into a voltage, and the voltage is input to the A / D converter 4 as stop detection means for detecting the stop of the DC motor 3 via R2.

  A capacitor C1 is connected between the input terminal of the A / D converter 4 and the ground, and noise is removed by the resistor R2 and the capacitor C1. A spark prevention diode D1 is connected to the DC motor 3. If the signal supplied from the A / D converter 4 is 0V, the control unit 1 determines that the DC motor 3 is stopped. The DC motor 3 rotates the rotating shaft 33 shown in FIG. 5 to rotate the eccentric cam 32 and the sensor shielding plate 34.

  FIG. 2 is a flowchart for explaining the operation of the motor control apparatus according to the embodiment of the present invention, and FIG. 3 is a timing chart.

  The DC motor 3 in this embodiment is used to drive the lifting mechanism 30 shown in FIG. At step SP1 (abbreviated as SP in the drawing) SP1 shown in FIG. 2, the controller 1 turns on the motor remote signal as shown in FIG. As a result, the DC motor 3 rotates, the eccentric cam 32 shown in FIG. 6 rotates, and the elevating arm 21 repeats raising and lowering.

  At this time, the control unit 1 monitors the output of the sensor 40 and waits for the first shielding signal to be output from the sensor 40 in step SP2. This shielding signal is output when the sensor shielding plate 34 shown in FIG. 6 passes through the groove portion of the sensor 40, and in FIG. 3A, the period rising in a pulse shape indicates the shielding signal.

  When determining that the first shielding signal is output, the control unit 1 waits for the second shielding signal to be output in step SP3. As shown in FIG. 3A, when it is determined that the second shielding signal has been output after the first shielding signal is output, the second time after the first shielding signal is output in SP4. The first time T11 until the shielding signal is output is calculated. This calculation is performed by counting the time from when the shielding signal is output until the next shielding signal is output by software processing.

  After the shielding signal is output and the time T11 is calculated, the motor remote signal is turned on and off n times during one rotation. The interval at which the motor remote signal is turned on and off is set to an interval at which the DC motor 3 can be sufficiently stopped. The motor remote signal is turned on as soon as it is detected that the DC motor 3 has been reliably stopped.

  For this purpose, in SP5, the motor remote signal is turned off as shown in FIG. 3B, and in step SP6, the output signal of the A / D converter 4 is discriminated to determine whether or not the rotation stop level is reached. to decide. If it is not at the rotation stop level, it waits until it reaches the rotation stop level. When the rotation stop level is reached, the motor remote signal is turned on in step SP7.

  In step SP8, it is determined whether or not a sensor shielding signal is output. If the sensor shielding signal is not output, the process returns to step SP5 to turn off the motor remote signal. In this way, the processing of steps SP5 to SP8 is repeated, and the motor remote signal is turned on and off n times.

  The motor remote signal is turned on and off n times, and when the second sensor shielding signal is output, it is determined at SP8. In step SP9, a second time T12 in which the motor remote signal is turned on and off n times after the sensor shielding signal is output is calculated. This second time T12 includes n inertia times ΔT from when the motor remote signal is turned off until the DC motor 3 is actually turned off. In step SP10, the average value of the inertia time ΔT is calculated based on the following equation (1).

Average value of ΔT = (T12−T11) / n (1)
Here, n is the number of times the motor remote signal is turned on and off, for example, 3 times.

  Equation (1) calculates a first time T11 from when the motor remote signal is turned on to rotate the DC motor 3 until the sensor 40 detects one rotation of the eccentric cam 32, and one of the eccentric cams 32 is calculated. When the motor remote signal is turned off during rotation and the stop of the DC motor 3 is detected by the output of the A / D converter 4, the DC motor 3 is re-rotated and this is repeated n times. The second time T12 required for one rotation of the cam 32 is calculated, and the average value of the inertia time ΔT is obtained by subtracting the first time T11 from the second time T12 and dividing by n. .

  In step SP11, taking into consideration the average value of the calculated inertia time ΔT, the timing at which the motor remote signal is turned off at the time of ascent and descent is determined and output. Thus, if the timing at which the motor remote signal is turned off is corrected, the inertial rotation angle of the DC motor 3 can be corrected and stopped at a predetermined position. More preferably, the output timing of the motor remote signal may be output earlier by the average value of the inertia time ΔT.

  Specifically, at the time of rising, as shown in FIG. 3B, from the time T13 until the motor remote signal is turned off after the sensor shielding signal is output, the inertia time ΔT when the DC motor 3 is stopped is reduced. If the average value is corrected so as to be turned off earlier, it is possible to stop at a predetermined stop position. T13 can be obtained by T13 = T1 × θ1 / 360 ° in the same manner as T2 shown in FIG.

  Further, even when descending, if the correction is made so that the motor remote signal is turned off earlier by the average value of the inertia time ΔT when the DC motor 3 is stopped from the time T14 from when the motor remote signal is turned on to when the motor remote signal is turned off, it can. T14 is obtained by T1 × (θ1−θ2) / 360 ° in the same manner as T3 shown in FIG.

  As described above, according to the embodiment of the present invention, the motor remote signal is turned on and off a plurality of times until the sensor 40 detects one rotation of the eccentric cam 32 and the motor remote signal is turned off. The time corresponding to the amount of deviation until the DC motor 3 stops is detected, and the timing for turning off the motor remote signal is determined in consideration of that time. It can be stopped at the position.

  It should be noted that the motor remote signal is turned on and off n times while the eccentric cam 32 rotates once without rotating the DC motor 3 and calculating the time T11 when the eccentric cam 32 rotates once. Then, the time T12 may be calculated, and the average value of the inertia time ΔT when the DC motor 3 is stopped may be calculated based on the following equation (2).

Average value of ΔT = (T12− (T12−total motor remote signal off time)) / n)
= Total motor remote signal off time / n (2)
That is, if the motor remote off time from when the motor remote signal is turned off during the time T12 to when the DC motor 3 stops is totaled and divided by the number n of times the motor remote signal is turned on and off, the average of the inertia time ΔT The value can be calculated.

  In the above-described embodiment, the average value of the inertia time ΔT when the motor 3 is stopped is obtained. However, the present invention is not limited to this, and the motor remote signal is turned on and off only once during the time T12. The inertia time ΔT may be obtained.

  Further, in the above description, the example in which the present invention is applied to control the DC motor 3 that lifts and lowers the separation mechanism in the color image forming apparatus has been described. However, in the image forming apparatus and other electronic devices, the lifting operation is performed by the motor. , It is also applicable to those that control the motor of a mechanism that moves back and forth or left and right.

  As mentioned above, although embodiment of this invention was described with reference to drawings, this invention is not limited to the thing of embodiment shown in figure. Various modifications and variations can be made to the illustrated embodiment within the same range or equivalent range as the present invention.

It is a block diagram of a motor control device in one embodiment of this invention. It is a flowchart for demonstrating operation | movement of the motor control apparatus in one Embodiment of this invention. It is a timing diagram for demonstrating operation | movement of the motor control apparatus in one Embodiment of this invention. It is a figure which shows the state at the time of the 4-color printing and monochrome printing by the conventional 4 series tandem type color image forming apparatus. It is a figure which shows the raising / lowering mechanism shown in FIG. It is a figure which shows the structure of the cam shown in FIG. It is a timing diagram which shows operation | movement of a raising / lowering mechanism.

Explanation of symbols

  DESCRIPTION OF SYMBOLS 1 Control part, 2 driver, 3 DC motor, 4 A / D converter, 30 raising / lowering mechanism, 32 Eccentric cam, 34 Sensor shielding board, 40 Sensor

Claims (4)

A motor control device for controlling rotation and stop of a motor,
Stop detecting means for detecting stop of the motor;
A signal output means for outputting a rotation and stop command signal of the motor;
Deviation detection means for detecting a deviation time from when the signal output means outputs a rotation command signal to rotate the motor to output a stop command signal until the stop detection means detects the stop of the motor. When,
A motor control device comprising: control means for controlling the signal output means to output the timing at which the stop command signal is output earlier by the deviation time. A rotation detecting means for detecting rotation of the motor;
A cam member to which the rotational speed of the motor is transmitted,
The signal output means outputs the motor stop command signal until the rotation detection means detects one rotation of the cam member, and rotates in response to the stop detection means detecting the motor stop. Output command signal,
The deviation detection means includes a first time required for one rotation of the cam member detected by the rotation detection means, and the cam member when the motor is stopped and re-rotated during one rotation of the cam member. The motor control device according to claim 1, wherein the shift time is calculated based on a difference from a second time required for one rotation. The signal output means repeatedly outputs the stop command signal and the rotation command signal a plurality of times during one rotation of the cam member,
3. The motor control device according to claim 2, wherein the deviation detection unit calculates an average value of the deviation times by dividing a difference between the first time and the second time by the plurality of times. The signal output means repeatedly outputs the stop command signal and the rotation command signal a plurality of times during one rotation of the cam member,
The deviation detection means calculates an average value of the deviation times by dividing the sum of the respective times until the stop detection means outputs each stop command signal and detects the stop of the motor by the plurality of times. The motor control device according to claim 2.

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