JP2008199707A - Motor controller - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To suppress rise of an induction voltage even if the induction voltage is generated in a motor which is rotary driven forcibly during stoppage by rotating the motor with a current based on the electromotive force. <P>SOLUTION: A drive control section 1 delivers a drive control signal for rotary driving a motor SM to a switching section 3. The switching section 3 rotary drives the motor SM by conducting the drive current from a DC drive power supply while switching based on the drive control signal. A detecting section 5 detects an induction voltage based on the electromotive force of the motor SM. Based on detection of the induction voltage, the drive control section 1 brings the motor SM into rotary state through the switching section 3 thus suppressing the rise of the induction voltage in a DC drive power supply line to the motor SM. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a motor control device, and more particularly to a motor control device suitable for being mounted on a copying machine, a multi function peripheral (MFP), or the like.

  For example, in a copying machine, it is well known that a toner image is transferred to a printing sheet fed from a sheet feeding cassette and fixed at a fixing unit, and the fixed sheet is discharged to the outside. The printing paper from the paper cassette until it is discharged is conveyed by a roller that is directly or indirectly driven by a motor.

  Similarly, in a mechanism for automatically feeding a plurality of printing sheets one by one in a copying machine or the like, the sheet is similarly fed and conveyed by a roller that is rotationally driven by a motor.

  However, in a copying machine or the like, an unexpected situation such as bending of the printing paper being conveyed or biting of foreign matter occurs, the normal conveyance operation of the printing paper is not performed, and the printing paper is jammed in the roller portion (jam: JAM) ) Occurs, the abnormality is detected and the operation is stopped.

  When the operation stops, the user can remove the print paper by opening and closing a door or the like disposed on the main body case and rotating or moving a predetermined dial or knob in order to remove the jammed print paper. Well done.

JP-A-5-134500 (Patent Document 1) is also of this type.
Japanese Patent Laid-Open No. 5-134500

  However, when removing jammed printing paper as described above, the printing paper is removed after turning off the power of the copier or the like. However, without removing the printing paper by turning a predetermined dial or knob, remove the printing paper by hand. When the jam correction process is performed by pulling out the roller, the roller rotates following the movement of the printing paper to be pulled out, and the motor also rotates by this rotation operation.

  Therefore, this rotation causes the motor to function as a generator and an electromotive voltage is generated at both ends of the motor coil, and the electromotive voltage is proportional to the rotational speed. Therefore, the electromotive voltage increases depending on the speed at which the printing paper is pulled out. This may cause problems with the operation of the copier.

  For example, in a copying machine or the like, it is common to control various electronic circuits by a microcomputer or the like. Even if the power of the copying machine or the like is turned off, the microcomputer or the like operates by an electromotive force from a motor and is expected. There is a concern that the operation will not be performed.

  Of course, when forcibly pulling out the printing paper, it is sufficient to provide a mechanism that idles the roller so that the motor does not rotate following the movement of the printing paper to be pulled out, but the mechanical mechanism becomes complicated. However, if the conventional configuration is to be realized, there is a drawback that the configuration needs to be changed.

  The present invention has been made to solve such a problem, and even if the rotation transmission mechanism to the motor is not idling, the electromotive voltage of the motor is not increased by a simple configuration, and it is difficult to be affected. An object is to provide a possible motor control device.

  In order to solve such a problem, a motor control device according to the present invention includes a DC motor, a detection unit that detects an electromotive voltage based on an electromotive force generated by the motor, and a drive that outputs a drive control signal that drives the motor. A control unit, and a switching unit for switching and energizing the DC drive current from the DC drive power source to the motor based on the drive control signal to rotationally drive the motor. In the drive control unit, the detection unit is activated. When the voltage is detected, the switching unit is controlled so that an electromotive force caused by the electromotive force flows to the common potential of the switching unit.

  In the motor control device of the present invention, when the drive control unit detects an electromotive voltage by the detection unit, the switching unit is controlled so that the electromotive current is supplied to the motor and the motor is rotationally driven. Is also possible.

  In the motor control device of the present invention, when the detection unit detects an electromotive voltage in a state where the interruption of the DC drive power supply is detected and rotation of the motor is stopped, the drive control unit controls the switching unit. A configuration to control is also possible.

  In the motor control device of the present invention, a configuration in which the detection unit detects an electromotive force at a level smaller than the DC drive power supply is also possible.

  In the motor control apparatus of the present invention, the motor may be a conveyance motor in an image forming apparatus that forms an image from image data.

  In such a motor control device according to the present invention, an electromotive voltage based on an electromotive force generated by a DC motor is detected by a detection unit, a drive control signal for driving the motor is output from the drive control unit, and a DC from a DC drive power source is output. The drive current is switched by the switching unit based on the drive control signal to rotate the motor, and when the detection unit detects the electromotive voltage, the electromotive force due to the electromotive force is caused to flow to the common potential of the switching unit. Since the switching unit is controlled by the drive control unit, the electromotive voltage from the motor is not increased and can be made less susceptible to the influence, and there is no need to provide a mechanical configuration for idling the rotation transmission mechanism to the motor. .

  In the motor control device of the present invention, when the detection unit detects an electromotive voltage, the drive control unit controls the switching unit so that the motor is rotated by energizing the electromotive current. The electromotive voltage from the motor is not increased, and the rotation of the motor is ensured and the printing paper or the like is hardly damaged.

  In the motor control device of the present invention, when the detection unit detects the electromotive voltage in a state where the interruption of the DC drive power supply is detected and the rotation drive of the motor is stopped, the drive control unit controls the switching unit. In the configuration to be controlled, it is possible to reliably consume the electromotive force generated when the motor is stopped, and not to increase the electromotive voltage from the motor, and to suppress the influence thereof.

  In the motor control device of the present invention, in the configuration in which the detection unit detects an electromotive force at a level smaller than the DC drive power supply, the electromotive force is detected before the electromotive voltage from the motor reaches the DC voltage of the DC drive power supply. It is difficult to cause a malfunction when the DC drive power source is applied by the electromotive voltage of the motor.

  In the motor control device of the present invention, when the motor is a paper conveyance motor in an image forming apparatus that forms an image from image data, it is difficult to damage the printing paper even if the jammed printing paper is forcibly pulled out.

  Embodiments of a motor control device according to the present invention will be described below with reference to the drawings.

  FIG. 1 is a schematic circuit diagram showing an embodiment of a motor control device according to the present invention.

  In FIG. 1, a drive control unit 1 sends a drive control signal for rotating a stepping motor (simply called a motor) SM, which will be described later, at a predetermined rotational speed, to FET transistors Q1, Q2, Q3, Q4, Q5 of the switching unit 3. , Q6, Q7, and Q8.

  The drive control unit 1 includes a CPU having a control arithmetic function as a main part, a ROM storing operation software of the CPU, and an input / output interface IO. The drive control unit 1 operates with a DC power source DC1, and detailed functions will be described later.

  Of the transistors Q1 to Q8 forming the switching unit 3, the drain of the transistor Q1 is connected to the DC drive power source DC2 through the switch SW from the connection point P1, and the source of the transistor Q1 is connected to the drain of the transistor Q2. A source of the transistor Q2 is connected to the ground GND, and a connection point P2 between the transistors Q1 and Q2 is connected to a bipolar winding (not shown) of the motor SM (hereinafter the same). The ground GND is a common potential (earth) of the switching unit 3.

  The drain of the transistor Q3 is connected to the connection point P1, the source of the transistor Q3 is connected to the drain of the transistor Q4, the source of the transistor Q4 is connected to the ground GND, and the connection point P3 of the transistors Q3 and Q4 is the motor. Connected to SM bipolar winding. As described above, one end of this bipolar winding is connected to the connection point P2.

  The drain of the transistor Q5 is connected to the DC drive power source DC2 via the connection point P4 and the switch SW, the source of the transistor Q5 is connected to the drain of the transistor Q6, the source of the transistor Q6 is connected to the ground GND, A connection point P5 between the transistors Q5 and Q6 is connected to another bipolar winding of the motor SM.

  The drain of the transistor Q7 is connected to the connection point P4, the source of the transistor Q7 is connected to the drain of the transistor Q8, the source of the transistor Q8 is connected to the ground GND, and the connection point P6 of the transistors Q7 and Q8 is the motor. Connected to SM bipolar winding. This bipolar winding also has one end connected to the connection point P5 as described above.

  In each of the transistors Q1 to Q8, a diode D connected in parallel in the direction opposite to the drive current between the drain and the source is for protection when the transistors Q1 to Q8 are switched and driven.

  The motor SM is of a stepping type and is a conventionally known one that rotates by switching energization of drive currents to a plurality of motor bipolar windings, and is not limited to the stepping type.

  The switch SW inserted in the DC drive power supply line between the DC drive power supply DC2 and the connection points P1 and P4 energizes and cuts off the DC drive power supply DC2 to the motor SM side. It has a function to detect opening and closing of the door. In conjunction with opening and closing of the door, it is turned on (ON) in the closed state and turned off (OFF) in the open state.

  The detection unit 5 includes an operational amplifier OP that compares the reference voltage Vf with the power supply voltage Vmm on the connection points P1, P4 (motor SM) side of the switch SW, and the power supply voltage Vmm exceeds the reference voltage Vf. At this time, it has a function of outputting the detection signal S to the drive control unit 1.

  The reference voltage Vf has a level (voltage) smaller than that of the normal DC drive power supply DC2, and is selected to be an electromotive voltage generated by the motor SM.

  That is, as shown in FIG. 2, it is set to a reference voltage Vf that is smaller than the DC drive power supply DC2 and greater than the voltage V1 that turns off the transistors Q1 to Q8. 2 is an electromotive force generated by pulling out the printing paper, for example.

  If the power supply voltage Vmm on the connection points P1 and P4 (motor SM) side is a regular DC drive power supply DC2, the drive control unit 1 includes the gates of the transistors Q1 and Q4, Q5 and Q8 of the switching unit 3, and the transistor Q3. And the gates of Q2, Q7, and Q6 are switched so as to be alternately turned on, and the motor SM is rotationally driven at a predetermined rotational speed through the operation of the switching unit 3.

  When the switch SW is turned off (OFF) and the power supply voltage Vmm on the connection points P1 and P4 (motor SM) decreases or disappears, the drive control unit 1 turns off the gates of the transistors Q1 to Q8 to turn off the motor. Stop rotation of SM.

  When the detection signal S is output when the power supply voltage Vmm on the connection points P1 and P4 (motor SM) side exceeds the reference voltage Vf under the rotation stop state of the motor SM in this way, the drive control unit 1 causes the transistor Q1 to And Q4, Q5 and Q8, and transistors Q3 and Q2 and Q7 and Q6 are alternately switched on to turn on the motor SM.

  Next, the operation of the motor control device according to the present invention will be briefly described.

  First, normal operation will be described. In this state, the switch SW is turned on (closed), the DC drive power source DC2 is applied to the connection points P1 and P4, and the detection unit 5 outputs the detection signal S1 to the drive control unit 1.

  Therefore, the drive control unit 1 alternately switches on and turns on the gates of the transistors Q1 and Q4, Q5 and Q8, and the gates of the transistors Q3 and Q2 and Q7 and Q6 of the switching unit 3.

  Therefore, in the switching unit 3, when the transistors Q1 and Q4 and Q5 and Q8 are turned on, one drive current flows to the ground GND via the connection point P1, the transistor Q1, the motor SM, and the transistor Q4, and the other drive current flows. The current flows to the ground GND through the connection point P4, the transistor Q5, the motor SM, and the transistor Q8.

  When the transistors Q3 and Q2, Q7 and Q6 are turned on, one drive current flows to the ground GND via the connection point P1, the transistor Q2, the motor SM, and the transistor Q3, and the other drive current flows to the connection point P4, the transistor Q6, It flows to the ground GND through the motor SM and the transistor Q7. Therefore, the motor SM is rotationally driven at a predetermined rotational speed.

  Then, when printing paper jam occurs, for example, when the opening / closing door of the copying machine is opened and the switch SW linked to this is opened (OFF), the DC drive voltage DC2 to the transistors Q1 to Q8 is cut off and the motor is turned off. The rotational drive of the SM is controlled to stop.

  After that, when the printing paper is pulled out, as shown in FIG. 2, the motor SM is forcibly driven to rotate to generate an electromotive voltage A. In the circuit configuration of FIG. , Q3, Q5, Q7, the voltage Vmm of the DC drive power supply lines (P1, P4) to the motor SM rises through the diode D connected in parallel to the switch SW side.

  Then, the detection unit 5 detects that the voltage Vmm on the connection points P1 and P4 side of the switch SW has increased and exceeded the reference voltage Vf, and outputs the detection signal S to the drive control unit 1, so that the drive control unit 1 outputs a drive control signal to the switching unit 3, and the on operations of the transistors Q1 and Q4, Q5 and Q8 of the switching unit 3, and the on operations of the transistors Q3 and Q2, Q7 and Q6 are alternately repeated.

  As a result, one drive current flows to the ground GND via the connection point P1, transistor Q2, motor SM, transistor Q4, and the other drive current flows to the ground GND via the connection point P4, transistor Q6, motor SM, transistor Q8. The motor SM is in a rotating state.

  Since the electromotive force due to the forced rotation of the motor SM is temporary and is not continued, the motor SM settles to stop.

  In such a motor control apparatus according to the present invention, the motor SM that is rotationally driven by the DC drive power source DC2, the detection unit 5 that detects the electromotive voltage based on the electromotive force by the motor SM, and the DC drive power source DC2 When the detecting unit 5 detects the electromotive voltage, the electromotive current generated by the electromotive force is applied when the detecting unit 5 detects the electromotive voltage by switching the energization of the DC driving current to the motor SM based on the driving control signal. And a drive control unit 1 for controlling the switching unit 3 to rotationally drive the motor SM.

  Therefore, when the printing paper is pulled out, the motor SM is forcibly rotated to generate an electromotive voltage. However, if the reference voltage Vf in the detection unit 5 is appropriately selected, the generated electromotive voltage is detected and the motor is detected. By turning the SM into a rotating state, an electromotive current based on the electromotive force is supplied to the ground GND, and an increase in the electromotive voltage in the DC drive power supply line to the motor SM is suppressed, so that the drive control unit 1 is unlikely to malfunction.

  Moreover, since it can be dealt with only by changing the operation of the drive control unit 1, for example, by changing the operation program, it can be dealt with by a simple configuration change, and there is no need to idle the rotation transmission mechanism to the motor SM depending on the machine configuration. .

  Further, when the motor SM is rotated, the braking force of the motor SM is also released, so that it is difficult to damage the printing paper and the constituent devices can be protected.

  In addition, in a state where the drive control unit 1 detects the interruption of the drive power supply voltage and stops the rotation driving of the motor SM, the detection unit 5 detects the electromotive voltage of the motor SM and rotates the motor SM. Therefore, it is possible to reliably consume the electromotive voltage of the motor SM, it is difficult to erroneously detect the closed (ON) state of the switch SW inserted in the power supply line to the motor SM, and it is possible to ensure operational safety. .

  By the way, in the motor control apparatus of this invention, when the detection part 5 detects an electromotive voltage, it is not limited to the structure which controls the switching part 3 so that the said motor SM may be rotationally driven.

  In other words, the transistors Q2, Q4, Q6, and Q8 can be turned on so that the electromotive current from the motor SM flows to the ground side, and the drive control unit 1 controls the switching unit 3 accordingly. Just do it.

  However, as described above, the configuration in which the switching unit 3 is controlled so as to rotationally drive the motor SM has an advantage that the braking force of the motor SM is also released and the printing paper is hardly damaged.

  Further, the switching unit 3 is not limited to the above-described configuration, and may be formed so as to switch the DC driving current from the DC driving power source DC2 to the motor SM to rotate the motor SM.

1 is a schematic block diagram showing an embodiment of a motor control device according to the present invention. It is a figure explaining operation | movement of the motor control apparatus of FIG.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Drive control part 3 Switching part 5 Detection part DC1 DC power supply DC2 DC drive power supply P1, P2, P3, P4 Connection point Q1, Q2, Q3, Q4, Q5, Q6, Q7, Q8 Transistor SM Motor SW switch

Claims (5)

A DC motor;
A detection unit for detecting an electromotive voltage based on an electromotive force generated by the motor;
A drive control unit for outputting a drive control signal for driving the motor;
A switching unit that rotationally drives the motor by energizing a DC drive current from a DC drive power source to the motor based on the drive control signal;
Comprising
The drive control unit controls the switching unit to cause an electromotive force generated by the electromotive force to flow to a common potential of the switching unit when the detection unit detects the electromotive voltage. 2. The motor control device according to claim 1, wherein when the detection unit detects the electromotive voltage, the drive control unit controls the switching unit so as to energize the electromotive current to the motor and drive the motor to rotate. . The drive control unit controls the switching unit when the detection unit detects the electromotive voltage in a state in which the rotation drive of the motor is stopped by detecting the interruption of the DC drive power supply. The motor control apparatus described. The motor control device according to claim 1, wherein the detection unit detects the electromotive force at a level smaller than the DC drive power source. The motor control apparatus according to claim 1, wherein the motor is a conveyance motor in an image forming apparatus that forms an image from image data.

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