JP2007166686A - Motor control device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To control a motor even if a connection failure occurs between a means for outputting a control signal and a means for driving the motor according to the control signal. <P>SOLUTION: A signal outputted from a control signal generation part 110 and a signal outputted from a microcomputer 100 or the control signal generation part 110 via a selector 140 are inputted to a motor driver 120. The microcomputer 100 detects whether the control signal outputted from the control signal generation part 110 is inputted to the motor driver 120 or not. When the microcomputer 100 detects that the control signal outputted from the control signal generation part 110 is not inputted to the motor driver 120, the microcomputer outputs a control signal, controls the selector so that the outputted control signal is inputted to the motor driver 120, and that the signal from the control signal generation part 110 is not inputted to the motor driver 120. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a technique for controlling a motor.

  In an image forming apparatus such as a copying machine, a stepping motor is used as a drive source of a transport mechanism that transports recording paper. FIG. 14 is a conventional example of a circuit for driving a stepping motor. The microcomputer 1 includes a ROM, a RAM, various input / output terminals, and the like, and controls the motor driver 3 according to a program stored in the ROM. The stepping motor 2 is driven in various excitation modes such as two-phase excitation and W1-2-phase excitation by controlling the current applied to the A phase (winding A) and the current applied to the B phase (winding B). Is done. The motor driver 3 is connected to the microcomputer 1 and the stepping motor 2, and is controlled by a plurality of control signals output from the microcomputer 1, and the current (A 1) that flows through the winding A and the winding B of the stepping motor 2. , A2, B1, and B2).

Under this configuration, the stepping motor 2 is controlled to rotate the shaft of the stepping motor 2. However, if an abnormality occurs in the stepping motor 2 and an overcurrent flows, the motor peripheral circuit It will lead to destruction of. For this reason, for example, as disclosed in Patent Document 1, a technique has been devised in which it is detected that an overcurrent has flowed to the stepping motor 2 and the power supply to the stepping motor 2 is stopped.
JP 2004-282920 A

  By the way, the case where the stepping motor 2 does not operate normally is not only the case where an abnormality occurs in the stepping motor 2. For example, if any of a plurality of control signals output from the microcomputer 1 is not input to the motor driver 3 due to poor connection between the microcomputer 1 and the motor driver 3, the microcomputer 1 controls the motor driver 3 normally. There is a possibility that problems such as step-out and reverse rotation may occur. When such a problem occurs, the technique disclosed in Patent Document 1 cannot detect an abnormality of the control line, and thus cannot prevent a problem such as step-out or reverse rotation. .

  The present invention has been made under the background described above, and its purpose is to provide a motor even when a connection failure occurs between a means for outputting a control signal and a means for driving a motor in accordance with the control signal. It is to be able to control.

  In order to solve the above-described problems, the present invention provides a motor, first control signal generating means for outputting a plurality of control signals belonging to the first system and a plurality of control signals belonging to the second system, and the first system A second control signal generating means for outputting a plurality of control signals belonging to the control signal, a control signal belonging to the first system output from the first control signal generating means, and a first output from the second control signal generating means. A signal selection unit that selects and outputs one of the control signals belonging to the system according to the selection signal that is input, the control signal that belongs to the first system output from the signal selection unit, and the first control signal In accordance with a control signal belonging to the second system output from the generating means, a motor control means for controlling the current flowing through the motor to drive the motor; and a control signal belonging to the second system is the motor control means Enter When the detecting means detects that at least any one of a plurality of control signals belonging to the second system is not input to the motor control means, The detecting means detects that a plurality of control signals belonging to two systems are prevented from being input to the motor control means and a plurality of control signals belonging to the second system are being input to the motor control means. If so, a selection signal instructing output of a control signal belonging to the first system outputted from the first control signal generating means is outputted to the signal selection means, and a plurality of control signals belonging to the second system Output from the second control signal generating means when the detecting means detects that at least one of them is not input to the motor control means To provide a motor control device and a control means for outputting to said signal selecting means a selection signal for instructing the output of the control signals belonging to the first system that.

  The present invention also includes a motor driven in the first excitation mode or the second excitation mode, control signal generating means for outputting a plurality of control signals belonging to the first system and a plurality of control signals belonging to the second system, When only a plurality of control signals belonging to the first system output from the control signal generating means are input, the current flowing through the motor is controlled to drive the motor in the first excitation mode, and the control signal When a plurality of control signals belonging to the first system and a plurality of control signals belonging to the second system output from the generating means are input, the current flowing through the motor is controlled to control the motor in the second excitation mode. Among the plurality of control signals belonging to the second system, the detection means for detecting whether or not a plurality of control signals belonging to the second system are input to the motor control means, Prevention means for preventing a plurality of control signals belonging to the second system from being inputted to the motor control means when the detection means detects that at least one of them is not inputted to the motor control means; A motor control device is provided.

  According to the present invention, the motor can be controlled even when a connection failure occurs between the means for outputting the control signal and the means for driving the motor in response to the control signal.

[First Embodiment]
FIG. 1 is a diagram illustrating a hardware configuration of a main part of an image forming apparatus according to an embodiment of the present invention. The microcomputer 100 is a so-called one-chip microcomputer provided with a ROM, a RAM, and various input / output terminals. The microcomputer 100 operates in accordance with a program recorded in the ROM, and controls the control signal generator 110, the selector 140, the voltage fixing circuit C2, the display unit 150, the nonvolatile memory 160, and each unit of the image forming apparatus (not shown). To do.

  Further, the microcomputer 100 includes an input terminal ADIN. The microcomputer 100 converts the voltage value of the ADIN terminal into a digital value. The microcomputer 100 can know the voltage value of the ADIN terminal from this digital value. Further, the microcomputer 100 includes SEL, B11, B12, SH / LD, CLOCK, and PO1 as output terminals. The SEL is connected to the selector 140 and changes the voltage level of the terminal to the L level or the H level. B11 and B12 are connected to the selector 140 and set the voltage level of the terminals to the H level or the L level. SH / LD is connected to the control signal generator 110, and sets the voltage level of the terminal to H level or L level. The CLOCK is connected to the control signal generator 110 and outputs a clock pulse (control instruction signal) for controlling the control signal generator 110. PO1 is connected to the transistors TR1 to TR4, and is used to control ON / OFF of the connected transistors.

  Further, the microcomputer 100 reserves an area (counter N) in the RAM for storing the number of clock pulses output from the CLOCK. Further, the microcomputer 100 stores the voltage table TB1 shown in FIG. In the voltage table TB1, predetermined voltage values (X1 to X16) are stored in association with the values 1 to 16 counted by the counter N. This voltage value is the voltage value of the voltage input to the ADIN terminal when there is no abnormality in the connection lines connected to the input terminals CLK1 to CLK6 of the motor driver 120 described later after outputting the clock pulse. Yes. Further, the microcomputer 100 stores the output table TB2 shown in FIG. In the output table TB2, the voltage levels of the terminals B11 and B12 are stored in association with the value of the counter N.

  The display unit 150 includes a liquid crystal display, and displays various menus and messages under the control of the microcomputer 100. The non-volatile memory 160 is a memory that permanently stores data, stores various data under the control of the microcomputer 100, and outputs the stored data to the microcomputer 100.

  The control signal generator 110 is connected to the microcomputer 100, the selector 140, and the motor driver 120. The control signal generator 110 is controlled by the microcomputer 100 and sets the voltage levels of the output terminals OUT1 to OUT6 to H level or L level (outputs a control signal) in order to control the motor driver 120. SH / LD-IN which is an input terminal is connected to SH / LD of the microcomputer 100, and CLK-IN is connected to CLOCK of the microcomputer 100. Further, OUT1 and OUT2 which are output terminals are connected to the selector 140, and OUT3 to OUT6 are connected to input terminals CLK3 to CLK6 of a motor driver 120 described later via resistors R1 to R4. The control signal generation unit 110 stores the output pattern table TB3 shown in FIG. 4. When the level of the SH / LD-IN terminal becomes the L level, the value of the pointer indicating the sequence of the patterns P1 to P16 is stored. It is initialized to “1”. When a clock pulse is input to CLK-IN after the level of SH / LD-IN becomes H level, the voltage level stored in the column indicated by the pointer value is set from each terminal at the rising edge of the clock pulse. The counter N is incremented at the falling edge of the clock pulse. For example, when the value of the pointer is “1”, the voltage level of each output terminal of the control signal generator 110 is the voltage stored in the column P1, that is, OUT1 = H, OUT2 = H, OUT3 = L. , OUT4 = L, OUT5 = L, and OUT6 = H. When the next clock pulse is input, the control signal generation unit 110 outputs the voltage level stored in the column indicated by the pointer value from each terminal. For example, when the value of the pointer is incremented to “2”, the voltage level of each output terminal is the voltage stored in the column of P2, that is, OUT1 = H, OUT2 = H, OUT3 = H, OUT4 = L, OUT5 = H, and OUT6 = L. When the pointer value is incremented to “17”, the control signal generator 110 returns the pointer value to “1”.

  The selector 140 is connected to the microcomputer 100, the control signal generator 110, and the motor driver 120. When the voltage level of the SEL terminal of the microcomputer 100 is H level, the selector 140 outputs the H level or L level voltage level output from B11 of the microcomputer 100 from the output terminal SOUT1, and the microcomputer 140. The voltage level of H level or L level output from B12 of 100 is output from the output terminal SOUT2. On the other hand, when the voltage level of the SEL terminal of the microcomputer 100 is L level, the selector 140 outputs the H level or L level voltage level output from the OUT1 terminal of the control signal generator 110 from the output terminal SOUT1. At the same time, the H level or L level voltage level output from the OUT2 terminal of the control signal generator 110 is output from the output terminal SOUT2.

  The motor 130 is a bipolar stepping motor and is connected to the motor driver 120. In the motor 130, the current flowing through the winding A and the winding B is controlled and driven in the W1-2 phase excitation mode or the two phase excitation mode. The motor 130 is connected to a conveyance mechanism (not shown) that conveys the recording paper. When the shaft of the motor 130 rotates, the recording paper is sent out from the paper tray of the image forming apparatus, and the sent recording paper forms an image. Move on the transport path in the device.

  The motor driver 120 is connected to the selector 140, the control signal generator 110, and the motor 130. The motor driver 120 includes input terminals CLK1 to CLK6. Based on the voltage levels of these terminals, currents flowing through the windings A and B of the motor 130 (flowing from the output terminals A1, A2, B1, and B2). Current) is controlled, and the motor 130 is driven in the W1-2 phase excitation mode or the two phase excitation mode.

(When operating in W1-2 phase excitation mode)
As shown in FIG. 5, in the motor driver 120, when the voltages of the terminals CLK1 to CLK6 are CLK1 = H, CLK2 = H, CLK3 = L, CLK4 = L, CLK5 = L, CLK6 = H (Pattern P1), 100% current flows from the terminal A1 to the terminal A2, and 33% current flows from the terminal B1 to the terminal B2. As a result, the current vector of the motor 130 becomes T1 in FIG. Further, as shown in FIG. 5, when the voltages at the CLK1 to CLK6 terminals are CLK1 = H, CLK2 = H, CLK3 = H, CLK4 = L, CLK5 = H, CLK6 = L (pattern P2 ), A current of 67% flows from the terminal A1 to the terminal A2, and a current of 67% flows from the terminal B1 to the terminal B2. As a result, the current vector of the motor 130 becomes T2 in FIG. Similarly, when the voltage at each terminal of CLK1 to CLK6 sequentially changes from the pattern P3 to the pattern P16, the direction and current value of the current flowing through the winding A as shown in FIG. The direction and current value of the current flowing through the winding B are controlled. As a result, the current vector of the motor 130 sequentially changes from T3 to T16 as shown in FIG.

(When operating in 2-phase excitation mode)
As shown in FIG. 6, when the voltage of each terminal of CLK3 to CLK6 becomes L level and CLK1 = H and CLK2 = H, the motor driver 120 has 100% current from the terminal A1 to the terminal A2. And a 100% current flows in the direction from the terminal B1 to the terminal B2. As a result, the current vector of the motor 130 becomes T1 in FIG. 7B. Further, as shown in FIG. 6, when the voltage of each terminal of CLK3 to CLK6 becomes L level and CLK1 = L and CLK2 = H, 100% current flows from the terminal A2 to the terminal A1, 100% current flows from the terminal B1 to the terminal B2. As a result, the current vector of the motor 130 becomes T2 in FIG. Further, as shown in FIG. 6, when the voltage of each terminal of CLK3 to CLK6 becomes L level and CLK1 = L and CLK2 = L, 100% current flows from the terminal A2 to the terminal A1, 100% current flows from the terminal B2 to the terminal B1. As a result, the current vector of the motor 130 becomes T3 in FIG. Further, as shown in FIG. 6, when the voltage of each terminal of CLK3 to CLK6 becomes L level and CLK1 = H and CLK2 = L, 100% current flows from the terminal A1 to the terminal A2, 100% current flows from the terminal B2 to the terminal B1. As a result, the current vector of the motor 130 becomes T4 in FIG.

  The voltage dividing circuit C1 is a circuit for dividing the voltage of CLK1 to CLK6 which is an input terminal of the motor driver 120. R11 is connected to CLK1, R12 is connected to CLK2, R13 is connected to CLK3, R14 is connected to CLK4, R15 is connected to CLK5, and R16 is connected to CLK6. R11 to R16 are connected to R17 connected to GND and ADIN of the microcomputer 100. The voltages of CLK1 to CLK6 are divided by the voltage dividing circuit C1. The voltage at the connection point between R11 to R16 and R17 is detected by the microcomputer 100. The resistance values of R11 to R17 are different from each other.

  The voltage fixing circuit C2 is a circuit for fixing the voltages of CLK3 to CLK6 to L level, and includes transistors TR1 to TR4. The base of each transistor is connected to the output terminal PO1 of the microcomputer 100, and the emitter of each transistor is connected to GND. The collector of the transistor TR1 is connected to the CLK4 via the resistor R5, the collector of the transistor TR2 is connected to the CLK3 via the resistor R6, and the collector of the transistor TR3 is connected to the CLK6 via the resistor R7. The collector of the transistor TR4 is connected to CLK5 through the resistor R8. Here, the resistance values of the resistors R5 to R8 are larger than those of the resistors R1 to R4. When the voltage level of the PO1 terminal of the microcomputer 100 is H level, each transistor is turned on, and the voltages of CLK3 to CLK6 are lower than the voltage level that the motor driver 120 determines to be L level due to the resistance voltage division. , Fixed at L level. On the other hand, when the voltage level of the PO1 terminal of the microcomputer 100 is L level, each transistor is turned OFF and the collector is opened, so that the voltage levels of CLK3 to CLK6 are the terminals OUT3 to OUT6 of the control signal generator 110. Voltage level.

[Operation of the embodiment]
Next, the operation of this embodiment will be described.
When an instruction to form an image on the recording paper is input to the microcomputer 100, the microcomputer 100 first initializes the counter N and sets the value of the counter N to “1” in order to operate the motor 130 to convey the recording paper. (FIG. 8: Step SA1). Next, the microcomputer 100 sets the voltage level of the SEL terminal to the L level (step SA2). As a result, the selector 140 outputs the voltage levels of the OUT1 terminal and OUT2 terminal of the control signal generator 110 from the SOUT1 and SOUT2 to the motor driver 120. Further, the microcomputer 100 sets the level of the PO1 terminal to the L level (step SA3). As a result, the collector terminals of the transistors TR1 to TR4 are opened. Further, the microcomputer 100 sets the level of the SH / LD terminal to the L level (step SA4). When SH / LD becomes L level, the level of the SH / LD-IN terminal of the control signal generator 110 becomes L level. When the level of the SH / LD-IN terminal becomes L level, the control signal generation unit 110 initializes the values of pointers pointing to the columns of the patterns P1 to P16 of the output pattern table TB3 to “1”. .

  The microcomputer 100 sets the SH / LD terminal to the L level, and then sets the SH / LD terminal level to the H level (step SA5). Then, after the SH / LD terminal is set to the H level, one clock pulse is output from the CLOCK terminal (step SA6). Here, when a clock pulse is output from CLOCK, the voltage levels of the output terminals OUT1 to OUT6 of the control signal generator 110 are the levels (OUT1 = H, OUT2) stored in the column indicated by the pointer value (1). = H, OUT3 = L, OUT4 = L, OUT5 = L, OUT6 = H), and the voltage levels of the CLK1 to CLK6 terminals of the motor driver 120 are CLK1 = H, CLK2 = H, CLK3 = L, CLK4 = L, CLK5 = L and CLK6 = H.

  Here, the voltage levels of the input terminals CLK1 to CLK6 are divided by the voltage dividing circuit C1, and the divided voltage is input to the ADIN terminal. The microcomputer 100 detects the voltage value of the ADIN terminal (step SA7), and determines whether or not the detected voltage value is the same as the predetermined voltage value stored in advance. Specifically, the microcomputer 100 reads the voltage value stored in the voltage table TB1 in association with the same value as the counter N from the voltage table TB1. Here, when the detected voltage value is the same as the predetermined voltage value read from the voltage table TB1 (FIG. 9: Step SA8; YES), the microcomputer 100 is connected to CLK1 to CLK6 of the motor driver 120. Judge that there is no abnormality in the connecting line. Then, the microcomputer 100 determines whether the image formation on the recording paper is completed and the recording paper is discharged out of the image forming apparatus (step SA9).

  If NO is determined in step SA9, the value of the counter N is incremented (step SA10). Then, it is determined whether or not the value of the counter N is 17 or more. When the value of the counter N is less than “17” (step SA11; NO), the microcomputer 100 shifts the process flow to step SA6, and when the value of the counter N becomes “17” or more. (Step SA11; YES), the value of the counter N is initialized to “1” (step SA12), and then the process flow is shifted to step SA6.

  When the processing from step SA6 to step SA12 is repeated and clock pulses are sequentially output from the CLOCK terminal, the control signal generator 110 sequentially changes the levels of the terminals OUT1 to OUT6 as shown in FIG. As a result, the current flowing through the winding A and the current flowing through the winding B change as shown in FIG. 5, and as a result, the torque vector of the rotor of the motor 130 changes from T1 as shown in FIG. The shaft of the motor 130 is rotated in order until T16. If the microcomputer 100 determines YES in step SA9, the microcomputer 100 ends the process.

  On the other hand, if the microcomputer 100 determines NO in step SA8, the microcomputer 100 determines that there is an abnormality in the connection lines connected to CLK1 to CLK6 of the motor driver 120. If the microcomputer 100 determines NO in step SA8, the microcomputer 100 identifies an abnormal connection line based on the detected voltage value of the ADIN terminal (step SA13). When the microcomputer 100 determines that there is an abnormality in the connection line connected to CLK1 or CLK2 (step SA14; YES), the microcomputer 100 stores the abnormality in the connection line in the nonvolatile memory 160 (step SA15). . Then, the microcomputer 100 displays a message notifying that there is an abnormality in the circuit that controls the motor 130 on the display unit 150 (step SA16), and ends the process.

On the other hand, when the microcomputer 100 determines that there is an abnormality in the connection lines connected to CLK3 to CLK6 (step SA14; NO), the microcomputer 100 sets the voltage level of the terminal PO1 to the H level (step SA17). Thereby, the transistors TR1 to TR4 are turned on, and the voltage levels of the terminals CLK3 to CLK6 are fixed to the L level.
Here, since CLK3 to CLK6 are fixed at the L level, the motor 130 is driven in the two-phase excitation mode thereafter. Next, the microcomputer 100 sets the voltage level of the output terminal SEL to the H level (step SA18). Thus, the selector 140 outputs the voltage levels of the output terminals B11 and B12 of the microcomputer 100 from SOUT1 and SOUT2.

  Next, the microcomputer 100 sets the voltage levels of the terminals B11 and B12 with reference to the value of the counter N and the output table TB2 (step SA19). For example, when the counter value is “1”, referring to the output table TB2, the voltage levels stored in association with “1” are B11 = H and B12 = H. The voltage levels at the terminals B11 and B12 are [B11 = H, B12 = H]. As a result, the voltage levels of CLK1 and CLK2 of the motor driver 120 become [CLK1 = H, CLK2 = H]. Since CLK3 to CLK6 are at L level, as shown in FIG. 6, 100% current flows from the terminal A1 to the terminal A2, and 100% current flows from the terminal B1 to the terminal B2. As a result, the current vector of the motor 130 becomes T1 in FIG. 7B.

  Next, the microcomputer 100 determines whether or not the conveyance of the recording paper is finished. When the conveyance of the recording paper has been completed (step SA20; YES), the microcomputer 100 stores in the nonvolatile memory 160 that there is an abnormality in the connection line (step SA15). Then, the microcomputer 100 displays a message notifying that there is an abnormality in the circuit that controls the motor 130 on the display unit 150 (step SA16), and ends the process.

  On the other hand, if the conveyance of the recording paper is not completed (step SA20; NO), the value of the clock pulse counter N is incremented (step SA21). If the clock pulse counter value is “5” or more (step SA22; YES), the counter value is initialized to “1” (step SA23). Thereafter, the microcomputer 100 shifts the process flow to step SA19.

  As shown in FIG. 3, the microcomputer 100 changes the voltage levels of the terminals B11 and B12 from [B11 = H, B12 = H] → [B11 = L, B12 = H] → [B11 = L, B12 = L. ] → [B11 = H, B12 = L] → [B11 = H, B12 = H]..., The voltage levels of CLK1 and CLK2 of the motor driver 120 are changed to [ CLK1 = H, CLK2 = H] → [CLK1 = L, CLK2 = H] → [CLK1 = L, CLK2 = L] → [CLK1 = H, CLK2 = L] → [CLK1 = H, CLK2 = H]・ Change. Accordingly, the current flowing through the winding A and the current flowing through the winding B change as shown in FIG. 6, and the current vector of the motor 130 changes from T1 to T2 as shown in FIG. 7B. → T3 → T4 → T1... Sequentially change so that the shaft of the motor 130 rotates.

  As described above, according to this embodiment, even when there is an abnormality in the connection line connected to the input terminal of the motor driver 120, the conveyance of the recording paper can be continued without stopping the motor 130. it can.

[Second Embodiment]
Next, a second embodiment of the present invention will be described. FIG. 10 is a diagram illustrating a hardware configuration of a main part of an image forming apparatus according to the second embodiment of the present invention. This embodiment is different from the first embodiment in that the selector 140 is not provided, OUT1 of the control signal generator 110 is connected to CLK1 of the motor driver 120, and OUT2 is connected to CLK2. The configuration is the same as in the first embodiment.

[Operation of the embodiment]
When an instruction to form an image on the recording paper is input to the microcomputer 100, the microcomputer 100 first initializes the counter N and sets the value of the counter N to “1” in order to operate the motor 130 to convey the recording paper. (FIG. 11: Step SB1). Further, the microcomputer 100 initializes the frequency of the clock pulse output from the CLOCK terminal to set the frequency f1 (step SB2). Further, the microcomputer 100 sets the level of the PO1 terminal to the L level (step SB3). As a result, the collector terminals of the transistors TR1 to TR4 are opened. Further, the microcomputer 100 sets the level of the SH / LD terminal to the L level (step SB4). When SH / LD becomes L level, the level of the SH / LD-IN terminal of the control signal generator 110 becomes L level. When the level of the SH / LD-IN terminal becomes L level, the control signal generation unit 110 initializes the values of pointers pointing to the columns of the patterns P1 to P16 of the output pattern table TB3 to “1”. .

  The microcomputer 100 sets the SH / LD terminal to the L level, and then sets the level of the SH / LD terminal to the H level (step SB5). Then, after setting the terminal of the SH / LD terminal to the H level, one clock pulse is output from the CLOCK terminal (step SB6). Here, when a clock pulse is output from CLOCK, the voltage levels of the output terminals OUT1 to OUT6 of the control signal generator 110 become the levels stored in the column indicated by the pointer value (1). The voltage levels of the CLK1 to CLK6 terminals are CLK1 = H, CLK2 = H, CLK3 = L, CLK4 = L, CLK5 = L, and CLK6 = H.

  Here, the voltage levels of the input terminals CLK1 to CLK6 are divided by the voltage dividing circuit C1, and the divided voltage is input to the ADIN terminal. The microcomputer 100 detects the voltage value of the ADIN terminal (step SB7), and determines whether or not the detected voltage value is the same as the predetermined voltage value stored in advance. Specifically, the microcomputer 100 reads the voltage value stored in the voltage table TB1 in association with the same value as the counter N from the voltage table TB1. Here, when the detected voltage value is the same as the predetermined voltage value read from the voltage table TB1 (FIG. 12: step SB8; YES), the microcomputer 100 is connected to CLK1 to CLK6 of the motor driver 120. It is determined that there is no abnormality in the connected connection line, and then it is determined whether or not the image formation on the recording paper is completed and the recording paper is discharged out of the image forming apparatus (step SB9).

  If NO is determined in step SB9, the value of counter N is incremented (step SB10). Then, it is determined whether or not the value of the counter N is 17 or more. When the value of the counter N is less than “17” (step SB11; NO), the microcomputer 100 shifts the process flow to step SB6, and when the value of the counter N becomes “17” or more. (Step SB11; YES), the value of the counter N is initialized to “1” (step SB12), and then the process flow is shifted to step SB6.

  On the other hand, if the microcomputer 100 determines NO in step SB8, it determines that there is an abnormality in the connection line connected to CLK1 to CLK6 of the motor driver 120. If the microcomputer 100 determines NO in step SB8, the microcomputer 100 identifies an abnormal connection line based on the detected voltage value of the ADIN terminal (step SB13). If the microcomputer 100 determines that there is an abnormality in the connection line connected to CLK1 or CLK2 (step SB14; YES), the microcomputer 100 stores the abnormality in the connection line in the nonvolatile memory 160 (step SB15). . Then, the microcomputer 100 displays a message notifying that there is an abnormality in the circuit that controls the motor 130 on the display unit 150 (step SB16), and ends the process.

  On the other hand, when the microcomputer 100 determines that there is an abnormality in the connection line connected to CLK3 to CLK6 (step S14; NO), the microcomputer 100 sets the voltage level of the terminal PO1 to the H level (step SB17). When the voltage level of the PO1 terminal of the microcomputer 100 becomes H level, the transistors TR1 to TR4 are turned on, and the voltages of CLK3 to CLK6 become lower than the voltage level that the motor driver 120 determines to be L level due to voltage division of the resistors. , Fixed at L level. Here, since the connection lines connected to CLK1 and CLK2 are normal and CLK1 and CLK2 are not fixed to the L level, only the voltage level of the CLK1 terminal and the voltage level of the CLK2 terminal change thereafter. The motor driver 120 drives the motor 130 in the two-phase excitation mode.

  Next, the microcomputer 100 changes the frequency f1 of the clock pulse initialized in step SB2 to a frequency f2 that is four times (step SB18), and outputs a clock pulse from the CLOCK terminal (step SB19). Then, the microcomputer 100 determines whether or not the conveyance of the recording paper is finished. When the conveyance of the recording paper has been completed (step SB20; YES), the microcomputer 100 stores in the nonvolatile memory 160 that there is an abnormality in the connection line (step SB15). Then, the microcomputer 100 displays a message notifying that there is an abnormality in the circuit that controls the motor 130 on the display unit 150 (step SB16), and ends the process. On the other hand, if the conveyance of the recording paper is not completed (step SB20; NO), the process flow is shifted to step SA19, and step SB19 is repeated.

  As described above, according to the present embodiment, the conveyance of the recording paper can be continued without stopping the motor 130 when the connection line connected to the input terminal of the motor driver 120 is abnormal.

[Modification]
As mentioned above, although embodiment of this invention was described, this invention is not limited to embodiment mentioned above, For example, you may implement the present invention, changing the above-mentioned embodiment as follows.

In the first embodiment described above, R11 may be connected to a connection line connecting OUT1 and the selector, and R12 may be connected to a connection line connecting OUT2 and the selector.
According to such an aspect, the motor driver 120 can be controlled by B11 and B12 via the selector 140 even if the OUT1 to OUT6 terminals are abnormal.

  In the first embodiment described above, when the motor driver is controlled by B11 and B12, that is, when the motor 130 is driven in the two-phase excitation mode, the rotation speed per unit time is the W1-2 phase excitation mode. You may make it adjust the frequency of the pulse output from B11 and B12 so that it may become the same rotation speed as time.

  In the embodiment described above, if the voltage levels of the six output terminals are changed in a predetermined pattern as shown in FIG. 4 in accordance with the input clock pulse, the control signal generator 110 is a microcomputer. It may be realized by a circuit that combines a shift register and an AND circuit.

  In the embodiment described above, when no abnormality has occurred, the motor 130 is driven in the W1-2 phase excitation mode, but is driven in the 1-2 phase excitation mode instead of the W1-2 phase excitation mode. You may do it.

  In the embodiment described above, the data stored in the non-volatile memory 160 is read when the power is turned on, and if it is stored that there is an abnormality in the connection line, the display unit 150 is controlled. It may be notified that there is an abnormality and the motor 130 may not be controlled.

  In the above-described embodiment, when it is detected that there is an abnormality in the connection line that connects the control signal generation unit 110 and the motor driver 120, the abnormality is notified by blinking light or sound. Also good.

  In the embodiment described above, the hardware configuration may be as shown in FIG. The aspect of FIG. 13 differs from the first embodiment described above in that a monitoring circuit C3 is provided. In the monitoring circuit C3, the resistance values of R18 and R19 are set so that a signal is output from the comparator COM1 only when there is an abnormality in the connection lines connected to CLK3 to CLK6. When the microcomputer 100 detects the signal output from the comparator COM1 at the input terminal IN1 and detects the signal output from the comparator COM1, the microcomputer 100 controls the motor driver 120 via the selector 140 to change the motor 130 to 2 Drive in phase excitation mode. In the second embodiment described above, an abnormality in the connection lines connected to CLK3 to CLK6 may be detected using the monitoring circuit C3.

FIG. 2 is a diagram illustrating a hardware configuration of a main part of the image forming apparatus according to the first embodiment of the present invention. It is the figure which showed the format of voltage table TB1. It is the figure which showed the format of output table TB2. It is the figure which showed the format of output pattern table TB3. It is the figure which showed the relationship between the voltage level of CLK1-CLK6, and the electric current sent through the winding A and the winding B. FIG. It is the figure which showed the relationship between the voltage level of CLK1-CLK6, and the electric current sent through the winding A and the winding B. FIG. FIG. 6 is a diagram showing a current vector of a motor 130. 3 is a flowchart showing a flow of processing performed by the microcomputer 100. 3 is a flowchart showing a flow of processing performed by the microcomputer 100. FIG. 6 is a diagram illustrating a hardware configuration of a main part of an image forming apparatus according to a second embodiment. 3 is a flowchart showing a flow of processing performed by the microcomputer 100. 3 is a flowchart showing a flow of processing performed by the microcomputer 100. FIG. 9 is a diagram illustrating a hardware configuration of a main part of an image forming apparatus according to a modified example of the present invention. It is the block diagram which showed the conventional circuit structure which drives a stepping motor.

Explanation of symbols

DESCRIPTION OF SYMBOLS 100 ... Microcomputer, 110 ... Control signal generation part, 120 ... Motor driver, 130 ... Motor, 140 ... Selector, 150 ... Display part, 160 ... Nonvolatile memory

Claims (5)

A motor,
First control signal generating means for outputting a plurality of control signals belonging to the first system and a plurality of control signals belonging to the second system;
Second control signal generating means for outputting a plurality of control signals belonging to the first system;
Either a control signal belonging to the first system output from the first control signal generating means or a control signal belonging to the first system output from the second control signal generating means is selected according to an input selection signal. Signal selection means for selecting and outputting,
According to the control signal belonging to the first system output from the signal selection means and the control signal belonging to the second system output from the first control signal generation means, the current flowing to the motor is controlled and the Motor control means for driving the motor;
Detection means for detecting whether a control signal belonging to the second system is input to the motor control means;
When the detection unit detects that at least one of the plurality of control signals belonging to the second system is not input to the motor control unit, the motors of the plurality of control signals belonging to the second system Prevention means for preventing input to the control means;
When the detection means detects that a plurality of control signals belonging to the second system are input to the motor control means, the control belonging to the first system output from the first control signal generation means A selection signal for instructing signal output is output to the signal selection means, and the detection means detects that at least one of the plurality of control signals belonging to the second system is not input to the motor control means. And a control unit that outputs to the signal selection unit a selection signal that instructs the output of the control signal belonging to the first system output from the second control signal generation unit. Storage means for storing data;
When the detection unit detects that at least one of the plurality of control signals belonging to the second system is not input to the motor control unit, the plurality of control signals belonging to the second system are The motor control device according to claim 1, further comprising storage control means for storing data indicating that the data is not correctly input to the storage means in the storage means. When the detection unit detects that at least one of the plurality of control signals belonging to the second system is not input to the motor control unit, the plurality of control signals belonging to the second system are The motor control device according to claim 1, further comprising notification means for notifying that the information is not correctly input to the means. The motor is a stepping motor that can be driven in a plurality of excitation modes,
When only a plurality of control signals belonging to the first system are input, the motor control means controls the current flowing through the motor so that the excitation mode of the motor becomes the first excitation mode. When both a plurality of control signals belonging to 2 and a plurality of control signals belonging to the second system are input, the current flowing through the motor is controlled so that the excitation mode of the motor becomes the second excitation mode. The motor control device according to claim 1, wherein A motor driven in the first excitation mode or the second excitation mode;
Control signal generating means for outputting a plurality of control signals belonging to the first system and a plurality of control signals belonging to the second system;
When only a plurality of control signals belonging to the first system output from the control signal generating means are input, the current flowing through the motor is controlled to drive the motor in the first excitation mode, and the control signal When a plurality of control signals belonging to the first system and a plurality of control signals belonging to the second system output from the generating means are input, the current flowing through the motor is controlled to control the motor in the second excitation mode. Motor control means driven by
Detecting means for detecting whether or not a plurality of control signals belonging to the second system are input to the motor control means;
When the detection means detects that at least one of the plurality of control signals belonging to the second system is not input to the motor control means, the motor of the plurality of control signals belonging to the second system A motor control device comprising: prevention means for preventing input to the control means.

Images