JP6673003B2 - Motor control device, sheet conveying device, image forming device, and motor control method - Google Patents

Description

  The present invention relates to a motor control device, a sheet conveying device, an image forming device, and a motor control method.

  For example, an image forming apparatus is equipped with many motors such as a motor for transporting a sheet used for image formation. As such a motor control technique, a CPU (Central Processing Unit) sends a drive signal such as a PWM (Pulse Width Modulation) signal corresponding to a control voltage applied to the motor driver to a motor driver, and based on the drive signal, A technique in which a driver drives a motor is known.

  When the motor is not driven, no current normally flows through the motor. However, if any abnormality occurs in the drive signal sent from the CPU to the motor driver, the motor driver tries to drive the motor at the maximum control voltage even when the motor is not driven, and the motor is seriously damaged. May be given. For this reason, it is required to prevent a malfunction when the motor is not driven.

  As a technique for preventing a malfunction when the motor is not driven, for example, a technique described in Patent Document 1 is known. According to this technique, when the motor is not driven, the control power of both isolation circuits of the two-split type is shut off to switch the driver unit to the motor non-drive state and to switch the brake device to the brake operation state. This keeps the motor stopped.

  However, the technology described in Patent Literature 1 is a configuration in which the brake device is set to a brake operation state when the motor is not driven and the stopped state of the motor is maintained, and the device configuration becomes large. For this reason, it is demanded to be able to more easily prevent a malfunction when the motor is not driven.

  In order to solve the above-described problems, the present invention provides a current detection unit that detects a current flowing through a motor when the motor is not driven, a voltage polarity determination unit that determines a polarity of a voltage corresponding to the detected current. Operating state management means for performing control to stop the motor in accordance with the polarity of the voltage.

  ADVANTAGE OF THE INVENTION According to this invention, there exists an effect that malfunction at the time of non-drive of a motor can be easily prevented.

FIG. 1 is a schematic configuration diagram of the image forming apparatus. FIG. 2 is a hardware configuration diagram of the motor control device. FIG. 3 is a block diagram illustrating a functional configuration example realized by the CPU. FIG. 4 is a diagram illustrating a phenomenon in which a current flows when the motor is not driven. FIG. 5 is a diagram illustrating a mask region set for a monitor voltage. FIG. 6 is a flowchart illustrating an example of a processing sequence executed by the CPU when the motor is not driven. FIG. 7 is a block diagram illustrating a functional configuration example of the upper CPU. FIG. 8 is a flowchart illustrating an example of a processing sequence executed by the upper CPU. FIG. 9 is a hardware configuration diagram of a modification in which a shunt resistor is provided on the motor power supply side. FIG. 10 is a hardware configuration diagram of a modification in which a hall sensor is provided instead of the shunt resistor. FIG. 11 is a schematic configuration diagram of a sheet feeding device connected to the image forming apparatus.

  Exemplary embodiments of a motor control device, a sheet conveying device, an image forming device, and a motor control method according to the present invention will be described below in detail with reference to the accompanying drawings. Hereinafter, a tandem color copying machine of an intermediate transfer system will be described as an example of an image forming apparatus to which the present invention can be applied.

<First embodiment>
FIG. 1 is a schematic configuration diagram of an image forming apparatus 1 of the present embodiment. As shown in FIG. 1, the image forming apparatus 1 includes an ADF (Auto Document Feeder) 1A and an apparatus main body 1B. The apparatus main body 1B includes a paper feed unit 3, an image reading unit 4, and an image forming unit 5.

  The ADF 1A includes a document tray 20, a document feed roller 21, a document transport belt 22, a document discharge roller 23, and a document discharge tray 24. The ADF 1A is openably and closably attached to the image reading unit 4 via an opening and closing mechanism such as a hinge.

  The document feed roller 21 separates documents one by one from the document bundle placed on the document tray 20 and transports the documents toward the image reading unit 4. The document transport belt 22 transports the document separated by the document feed roller 21 to the image reading unit 4. The document discharge roller 23 discharges a document discharged from the image reading unit 4 by the document conveying belt 22 to a document discharge tray 24 below the document tray 20.

  The image reading unit 4 includes a housing 40, a scanning optical unit 41, a contact glass 42, and a driving unit. The scanning optical unit 41 includes an LED unit and is provided inside the housing 40. The scanning optical unit 41 emits light from the LED unit in the main scanning direction, and is scanned in the sub-scanning direction in the entire irradiation area by the driving unit. As a result, the scanning optical unit 41 reads a two-dimensional color image of a document.

  The contact glass 42 is provided on an upper portion of the housing 40 of the image reading unit 4 and forms an upper surface of the housing 40. The driving means includes a wire (not shown) fixed to the scanning optical unit 41, a plurality of driven pulleys and a driving pulley bridged by the wire, and a motor for rotating the driving pulley.

  The paper supply unit 3 includes a paper supply cassette 30 and a paper supply unit 31. The paper feed cassette 30 stores paper as recording media having different paper sizes. The paper supply unit 31 transports the paper stored in the paper supply cassette 30 to the main transport path 70 of the image forming unit 5.

  A manual tray 32 is provided on the side surface of the image forming unit 5 so as to be openable and closable with respect to the image forming unit 5. You. The uppermost sheet in the manually inserted sheet bundle is sent out toward the main transport path 70 by the sending roller of the manual feed tray 32.

  The main transport path 70 is provided with a pair of registration rollers 70a. The registration roller pair 70a sandwiches the paper conveyed in the main conveyance path 70 between the rollers, and then feeds the paper toward the secondary transfer nip at a predetermined timing.

  The image forming unit 5 includes an exposure unit 51, a tandem image forming unit 50, an intermediate transfer belt 54, an intermediate transfer roller 55, a secondary transfer device 52, a fixing unit 53, and the like. The image forming section 5 has a main transport path 70, a reverse transport path 73, a paper discharge path 60, and the like.

  As shown in FIG. 1, the exposure unit 51 is disposed adjacent to the tandem image forming unit 50. The exposure unit 51 exposes a photosensitive drum 74 provided for each color of yellow, cyan, magenta, and black.

  The tandem image forming unit 50 includes four image forming units 75 of yellow, cyan, magenta, and black arranged on the intermediate transfer belt 54 and along the rotation direction of the intermediate transfer belt 54. Although not shown in detail, each image forming unit 75 includes a charging device, a developing device, a photoconductor cleaning device, a static eliminator, and the like around photoconductor drums 74 provided for the respective colors. . Each of the photosensitive drums 74 and the above-described devices provided therearound are unitized to form one process cartridge.

  The tandem image forming unit 50 forms a visible image (toner image) formed by using toner on each of the photosensitive drums 74 based on the image information read by the image reading unit 4 and separated by color. It has become. The visible image formed on each photoconductor drum 74 is transferred to the intermediate transfer belt 54 between each photoconductor drum 74 and the intermediate transfer roller 55.

  On the other hand, a secondary transfer device 52 is provided on the opposite side of the tandem image forming unit 50 with the intermediate transfer belt 54 interposed therebetween. The secondary transfer device 52 has a secondary transfer roller 521 as a transfer member. The secondary transfer roller 521 is pressed against the intermediate transfer belt 54 to form a secondary transfer nip. In the secondary transfer nip, the toner image formed on the intermediate transfer belt 54 is configured to be transferred onto a sheet conveyed from the sheet feeding unit 3 via the main conveyance path 70.

  The sheet on which the toner image has been transferred at the secondary transfer nip is sent to the fixing unit 53 by a sheet transport belt 56 stretched over two support rollers 57.

  The fixing unit 53 is configured by pressing a pressure roller 59 against a fixing belt 58 which is an endless belt. The fixing unit 53 applies heat and pressure to the sheet by the pressing roller 59 to melt the toner of the toner image transferred to the sheet and fix the toner image on the sheet as a color image.

  The sheet on which the color image has been fixed in this way is stacked on a sheet discharge tray 61 outside the apparatus via a sheet discharge path 60 as a sheet discharge conveyance path.

  Further, as shown in FIG. 1, a reverse conveyance path 73 is provided below the secondary transfer device 52 and the fixing unit 53. The reversing conveyance path 73 is for reversing the front and back of the sheet discharged from the fixing unit 53 and supplying the sheet to the secondary transfer device 52 again via the main conveyance path 70 in order to form images on both sides of the sheet. Things.

  In the image forming apparatus 1 configured as described above, the ADF 1A functions as a sheet conveying device that conveys a document as an example of a sheet. Further, the sheet feeding unit 31 of the sheet feeding unit 3, the main conveyance path 70, the reverse conveyance path 73, and the paper ejection path 60 of the image forming unit 5 in the apparatus main body 1 </ b> B are each configured to convey a sheet as an example of a sheet Functions as a device. These sheet conveying apparatuses convey a sheet by rotating a roller member by the power of a motor. The image forming apparatus 1 of the present embodiment includes a motor control device described below to control the motors of these sheet conveying devices.

  FIG. 2 is a hardware configuration diagram of the motor control device 100 of the present embodiment. As shown in FIG. 2, the motor control device 100 according to the present embodiment includes a motor driver 110 that drives the motor M, an encoder (ENC) 120 that detects the number of revolutions of the motor M, and a current that flows through the motor M. It includes a shunt resistor 130 and a CPU 140 that controls the operation of the motor driver 110.

  In the present embodiment, a brushless motor is assumed as the motor M to be controlled. However, the motor M to be controlled is not limited to a brushless motor, and various types of motors M can be controlled. In the present embodiment, the encoder 120 is used to detect the rotation speed of the motor M. However, the rotation speed of the motor M may be detected by another method.

  The motor driver 110 includes a switching circuit to which terminals of windings of the motor M are connected. The motor driver 110 controls the operation of this switching circuit based on a PWM signal (an example of a drive signal) sent from the CPU 140 to adjust the amount of current flowing from the motor power supply Vcc to the ground GND through the motor M. , And drives the motor M with a desired control voltage. When the brake signal sent from the CPU 140 is turned ON (logical value “1”), the motor driver 110 shuts off the current flowing from the motor power supply Vcc to the ground GND through the motor M and stops the motor M. Next, the operation of the switching circuit is controlled.

  In the present embodiment, an example will be described in which a PWM signal is used as a drive signal sent from the CPU 140 to the motor driver 110. However, the drive signal may be a signal corresponding to a control voltage applied to the motor M. Not limited to signals. For example, a PFM signal (pulse frequency signal) may be used as a drive signal or an analog signal.

  The motor driver 110 has at least a terminal for inputting a PWM signal, a terminal for inputting a brake signal, and a terminal for inputting a start / stop signal. Among them, a terminal for inputting a PWM signal and a terminal for inputting a brake signal are connected to a CPU 140 (control signal output means 143 described later) via a harness, respectively. On the other hand, the output of the terminal for inputting the start / stop signal is fixed to the start side. In other words, the motor driver 110 is configured to control the operation of the switching circuit based on the PWM signal when the start / stop signal is on the start side. When a significant PWM signal (a PWM signal including an ON section (a section with a logical value of “1”) is sent via the harness, the operation of the switching circuit is controlled based on the PWM signal.

  In the present embodiment, the CPU 140 sends two signals, a PWM signal and a brake signal, to the motor driver 110. In addition, the CPU 140 sends a rotation direction signal indicating the rotation direction of the motor M. Is also good. In this case, the motor driver 110 further includes a terminal for inputting a rotation direction signal, and switches a switching element to be controlled in the switching circuit according to the rotation signal output from the terminal.

  In the present embodiment, it is assumed that the PWM signal and the brake signal sent from the CPU 140 to the motor driver 110 are negative logic signals (signals indicating that the Lo level is ON). Therefore, when a short-circuit failure occurs due to pinching in a harness for transmitting the PWM signal, the PWM signal becomes a signal in which ON sections are continuous, that is, a signal for driving the motor M with the maximum control voltage. Therefore, if such an abnormality occurs, the motor driver 110 may drive the motor M at the maximum control voltage while the motor M is not driven, and may seriously damage the motor M. Thus, in the present embodiment, the CPU 140 determines whether or not there is a malfunction when the motor M is not driven, and if so, turns on the brake signal to stop the motor M. If a short-circuit failure occurs due to pinching in the harness that sends the brake signal, the terminal for inputting the brake signal of the motor driver 110 is fixed to the ON side, so that the motor M remains stopped.

  Even when the PWM signal is a positive logic signal (a signal indicating that the Hi level indicates ON), the same malfunction occurs when an open failure such as a disconnection occurs in the harness that transmits the PWM signal. The above-mentioned function is effective. It is desirable that the motor driver 110 be configured to fix the output of the terminal for inputting the brake signal to the ON side regardless of whether a short circuit or an open circuit occurs when an abnormality occurs in the harness for transmitting the brake signal.

  The encoder 120 outputs an ENC signal according to the rotation speed of the motor M. Since the ENC signal is a signal indicating the current driving state of the motor M, it is used, for example, to perform speed feedback control of the motor M in the CPU 140.

  The shunt resistor 130 is, for example, a resistor connected in series between the motor M and the ground GND, and detects a current flowing through the motor M. That is, when a current flows through the motor M, a potential difference corresponding to the magnitude of the current is generated at both ends of the shunt resistor 130. From this potential difference, the current flowing through the motor M can be detected.

  The shunt resistor 130 is usually used for detecting an overcurrent when the motor M is driven. That is, the motor driver 110 limits the current so that the current detected by the shunt resistor 130 does not become excessive. In the present embodiment, a potential difference generated between both ends of the shunt resistor 130 is input to the CPU 140 as a monitor voltage, and is used to detect a current flowing through the motor M when the motor M is not driven. The current detection using the shunt resistor 130 is a method that can be performed particularly cheaply and easily among the methods for detecting the current flowing through the motor M.

  The CPU 140 controls the operation of the motor driver 110 by inputting a speed target value and a start / stop command from the host CPU and an ENC signal from the encoder 120 and outputting a PWM signal and a brake signal to the motor driver 110. Further, the CPU 140 inputs the above-described monitor voltage when the motor M is not driven, and determines whether or not there is a malfunction when the motor M is not driven based on the monitor voltage. When it is determined that the motor M is malfunctioning, the CPU 140 turns on the brake signal to stop the motor M, and notifies the upper CPU of the occurrence of the abnormality. Here, the non-driving state of the motor M refers to a state in which a command to drive the motor M from the host CPU to the CPU 140, that is, a start command of the motor M, a target speed value, or the like is not input. The host CPU is an example of a host control device that controls the operation of the entire image forming apparatus 1 including the motor control device 100 of the present embodiment. The CPU 140 of the motor control device 100 is communicably connected to the host CPU.

  FIG. 3 is a block diagram illustrating a functional configuration example realized by the CPU 140. As shown in FIG. 3, the CPU 140 includes, as functional components related to the motor control of the present embodiment, an operation state management unit 141, a control voltage calculation unit 142, a control signal output unit 143, and a voltage polarity determination unit. 144. These functional components are realized, for example, by the CPU 140 executing a predetermined control program. It should be noted that some or all of these functional components are not used by the CPU 140, which is a general-purpose processor, but by dedicated hardware such as an ASIC (Application Specific Integrated Circuit) or an FPGA (Field-Programmable Gate Array). It can also be achieved.

  The operation state management unit 141 outputs an instruction to the control voltage calculation unit 142 and the control signal output unit 143 so that the operation state of the motor M becomes an operation state according to a command from the host CPU. That is, when a start command of the motor M is input from the host CPU, the operation state management unit 141 instructs the control signal output unit 143 to turn off the brake signal, and together with the start instruction of the motor M, The speed target value input from the CPU is passed to the control voltage calculation means 142 to instruct the control voltage calculation means 142 to calculate the control voltage applied to the motor M. When a stop command for the motor M is input from the host CPU, the operation state management means 141 instructs the control signal output means 143 to turn on the brake signal, and stops the motor M.

  In addition, the operation state management unit 141 instructs the voltage polarity determination unit 144 to determine whether the motor M is malfunctioning when the motor M is not driven. When the voltage polarity determining means 144 determines that the motor M is malfunctioning, the operating state managing means 141 instructs the control signal output means 143 to turn on the brake signal and turns the motor M on. The CPU is stopped, and the host CPU is notified that an abnormality has occurred. When the voltage polarity determining means 144 determines that the motor M is being turned from the outside, the operating state managing means 141 notifies the host CPU that the motor M is being turned from the outside. Notice. The voltage polarity determining unit 144 determines a malfunction of the motor M based on the polarity of the monitor voltage when the motor M is not driven, which will be described later.

  The control voltage calculation unit 142 compares the target speed value passed along with the control voltage calculation instruction from the operation state management unit 141 with the current rotation speed of the motor M indicated by the ENC signal input from the encoder 120, and The control voltage applied to the motor M is calculated so as to correct the deviation. The control voltage calculated by the control voltage calculation means 142 is passed to the control signal output means 143.

  The control signal output unit 143 outputs a PWM signal according to the control voltage calculated by the control voltage calculation unit 142. Further, the control signal output unit 143 outputs a brake signal whose ON / OFF is controlled by the operation state management unit 141. As described above, the PWM signal and the brake signal output from the control signal output unit 143 are sent from the CPU 140 to the motor driver 110 via the harness, and input to each terminal of the motor driver 110, as described above.

  When the motor M is not driven, the voltage polarity determination unit 144 inputs a potential difference generated between both ends of the shunt resistor 130 that detects a current flowing through the motor M as a monitor voltage. Based on the polarity of the monitor voltage, the motor M It is determined whether or not a malfunction has occurred. That is, the polarity of the monitor voltage corresponding to the current flowing from the motor power supply Vcc to the ground GND through the motor M is made positive. At this time, when the polarity of the monitor voltage is positive, the voltage polarity determination unit 144 determines that the motor M is malfunctioning. On the other hand, when the polarity of the monitor voltage is negative, the voltage polarity determination unit 144 determines that the motor M is being rotated from the outside. Here, the state in which the motor M is being rotated from the outside means, for example, that the motor M has rotated around when a jam occurs in the image forming apparatus 1 and the operator pulls out a sheet (document or paper). For example, a state in which the motor M is rotating without depending on the driving of the motor driver 110.

  4A and 4B are diagrams illustrating a phenomenon in which a current flows when the motor M is not driven. FIG. 4A illustrates an example in which a short circuit has occurred in a harness that sends a PWM signal from the CPU 140 to the motor driver 110. FIG. 3B shows an example in which the motor M rotates while rotating in a jam.

  When a short-circuit failure occurs due to pinching in a harness that transmits a PWM signal, the PWM signal becomes a signal in which ON sections are continuous, and the motor driver 110 attempts to drive the motor M with the maximum control voltage. As a result, as shown in FIG. 4A, a motor drive current Id flows from the motor power supply Vcc through the motor M to the ground GND. Then, since the polarity of the monitor voltage corresponding to the motor drive current Id is positive, the voltage polarity determination means 144 of the CPU 140 determines that the motor M is malfunctioning.

  On the other hand, when the operator rotates the motor M during the jam processing for the image forming apparatus 1 by pulling out the sheet, the motor M operates as a generator. As a result, as shown in FIG. 4C, a motor generated current Ig flows from the ground GND to the motor power supply Vcc through the motor M. Then, since the polarity of the monitor voltage corresponding to the motor generated current Ig becomes negative, the voltage polarity determining means 144 of the CPU 140 determines that the motor M is being turned from the outside.

  As described above, the phenomenon that current flows when the motor M is not driven is caused not only when the motor M is malfunctioning due to a short-circuit failure of the harness that sends the PWM signal, but also when the motor M This also occurs when the motor M is being rotated from the outside, such as when the motor M is rotating. Therefore, if the configuration is such that it is determined that the motor M is malfunctioning when the current is flowing when the motor M is not driven, the motor M malfunctions even when the motor M is being turned from the outside. Is incorrectly determined to be Therefore, in the present embodiment, a monitor voltage corresponding to the current flowing when the motor M is not driven is input to the CPU 140, and the voltage polarity determining unit 144 of the CPU 140 causes the motor M to malfunction based on the polarity of the monitor voltage. Or whether the motor M is being turned from the outside.

  When no current flows through the motor M, normally, the potential difference between both ends of the shunt resistor 130 becomes zero, so that the value of the monitor voltage input to the CPU 140 also becomes zero. However, the monitor voltage may indicate a value other than zero even though no current flows through the motor M due to, for example, noise. Therefore, a configuration in which the voltage value range in which the absolute value is equal to or less than a predetermined reference value is set as the mask region, and the determination by the voltage polarity determination unit 144 is not performed if the monitor voltage value is within the mask region. desirable. That is, the voltage polarity determination means 144 determines the polarity of the monitor voltage when the value (absolute value) of the monitor voltage exceeds the reference value, and determines whether the motor M is malfunctioning based on the polarity of the monitor voltage. Alternatively, it is desirable to determine whether the motor M is being turned from the outside.

  FIG. 5 is a diagram illustrating a mask region set for a monitor voltage. The mask area is set, for example, in a range of about ± 10V. In the example shown in FIG. 5A, the value of the monitor voltage is not within the mask area, and the polarity of the monitor voltage is positive. Therefore, the voltage polarity determination unit 144 determines that the motor M is malfunctioning. . Further, in the example shown in FIG. 5B, since the value of the monitor voltage is not within the mask area and the polarity of the monitor voltage is negative, the voltage polarity determination unit 144 determines that the motor M is externally turned. It is determined that it is in the state of being.

  As described above, when the voltage polarity determination unit 144 determines that the motor M is malfunctioning, the operation state management unit 141 instructs the control signal output unit 143 to turn on the brake signal. The motor M is stopped, and the host CPU is notified that an abnormality has occurred. This can effectively prevent the malfunction of the motor M when the motor M is not driven. In addition, for example, when the host CPU performs control such as displaying a warning of occurrence of an abnormality on the operation panel, the cause of the malfunction of the motor M can be reduced. The operator can be urged to take measures to recover the abnormal condition early.

  Further, when the voltage polarity determination unit 144 determines that the motor M is being rotated from the outside, the operation state management unit 141 determines that the motor M is being rotated from the outside as described above. Notify the upper CPU. This notification is performed, for example, by controlling the upper CPU to display on the operation panel that a jam is being processed, or by starting a process of detecting a remaining sheet by inputting a signal of a sensor provided on a sheet conveyance path. It is used as useful information for judging timing. However, the notification from the operation state management means 141 to the upper CPU is not indispensable, and a configuration may be adopted in which necessary notification is performed as needed.

  Further, the operation state management unit 141 may be configured to have a function of determining whether the motor M is malfunctioning based on the polarity of the monitor voltage. In this case, the voltage polarity determination unit 144 determines the polarity of the monitor voltage, for example, when the value of the monitor voltage is not within the mask area, that is, when the value (absolute value) of the monitor voltage exceeds the reference value. The determination result indicating the polarity is passed to the operation state management unit 141. When the polarity of the monitor voltage is positive, the operation state management means 141 instructs the control signal output means 143 to turn on the brake signal to stop the motor M, and instructs the host CPU to To notify that an error has occurred. If the polarity of the monitor voltage is negative, the operation state management unit 141 notifies the host CPU that the motor M is being rotated from the outside.

  Next, the operation of the motor control device 100 of the present embodiment when the motor M is not driven will be described with reference to the flowchart of FIG. FIG. 6 is a flowchart illustrating an example of a processing sequence executed by CPU 140 when motor M is not driven.

  First, the operation state management means 141 determines whether or not the motor M is not driven (step S101). Here, when the motor M is being driven (step S101: No), the processing sequence ends as it is. On the other hand, when the motor M is not driven (step S101: Yes), the voltage polarity determination unit 144 reads the monitor voltage according to the instruction from the operation state management unit 141, and determines whether the value of the monitor voltage is within the mask area. It is determined whether or not it is (step S102). Here, if the value of the monitor voltage is within the mask area (step S102: Yes), the processing sequence ends as it is. On the other hand, when the value of the monitor voltage is not within the mask area (Step S102: No), the voltage polarity determination unit 144 determines whether the polarity of the monitor voltage is positive (Step S103).

  If the result of determination in step S103 is that the polarity of the monitor voltage is positive (step S103: Yes), the control signal output means 143 turns on the brake signal in accordance with the instruction from the operation state management means 141 (step S104). Then, the motor M is stopped. Further, the operation state management unit 141 notifies the upper CPU of the occurrence of the abnormality (step S105), and the processing sequence ends. On the other hand, if the result of determination in step S103 is that the polarity of the monitor voltage is negative (step S103: No), the operating state management means 141 notifies the host CPU that the motor is being turned from the outside ( Step S106), the processing sequence ends.

  As described above in detail with reference to a specific example, the motor control device 100 of the present embodiment inputs the monitor voltage corresponding to the current flowing through the motor M to the CPU 140 when the motor M is not driven, and Performs control to stop the motor M according to the polarity of the monitor voltage. Therefore, according to the motor control device 100 of the present embodiment, it is possible to easily prevent a malfunction when the motor M is not driven.

  In a conventional general motor control device, a start / stop signal is sent from a CPU to a motor driver in addition to a drive signal such as a PWM signal. When the start / stop signal is on the start side, the motor driver drives the motor based on the drive signal sent from the CPU. On the other hand, the motor control device 100 of the present embodiment has a configuration in which the start / stop signal is fixed to the start side in the motor driver 110 and the driving of the motor M is controlled only by the PWM signal, as described above. Accordingly, since it is not necessary to send a start / stop signal from the CPU 140 to the motor driver 110, it is possible to reduce the harness between the CPU 140 and the motor driver 110.

  In the motor control device 100 of the present embodiment having such a configuration, it is required to take stricter measures against a malfunction when the motor M is not driven than in a conventional general motor control device. That is, for example, when an abnormality such as a short circuit occurs due to pinching in a harness that sends a PWM signal from the CPU 140 to the motor driver 110, the motor driver 110 operates at the maximum control voltage even when the motor M is not driven. Attempting to drive M may cause serious damage to motor M. In the conventional general motor control device, the above-mentioned malfunction is rarely caused by an abnormality such as a short-circuit failure occurring in both the harness for transmitting the PWM signal from the CPU to the motor driver and the harness for transmitting the start / stop signal. Was the case. On the other hand, in the case of the configuration of the present embodiment in which the driving of the motor M is controlled only by the PWM signal, the malfunction described above occurs only when an abnormality such as a short-circuit failure occurs in the harness that transmits the PWM signal.

  However, in the motor control device 100 of the present embodiment, when the above-described malfunction occurs when the motor M is not driven, the malfunction is quickly detected from the polarity of the monitor voltage corresponding to the current flowing through the motor M, Since the CPU 140 performs control to stop the motor M, it is possible to effectively suppress the inconvenience of causing serious damage to the motor M due to the above malfunction.

  Further, according to the motor control device 100 of the present embodiment, the CPU 140 notifies the upper CPU that an abnormality has occurred when the motor M is stopped. By performing a control such as displaying a warning, it is possible to urge the operator to quickly recover from the abnormality that caused the malfunction of the motor M.

  Further, according to the motor control device 100 of the present embodiment, when it is determined that the motor M is being rotated from outside according to the polarity of the monitor voltage, the motor M is being rotated from outside. Is notified by the CPU 140 to the upper-level CPU. Using this information, the upper-level CPU controls the operation panel to indicate that a jam is being processed, or controls the sensor provided on the sheet conveyance path. By inputting a signal, it is possible to determine the start timing of the processing for detecting the remaining sheet.

  Further, according to the motor control device 100 of the present embodiment, when the value of the monitor voltage is not within the mask area but exceeds the reference value, the polarity of the monitor voltage is determined, and the motor M is determined according to the determination result. , And the notification to the host CPU is performed, so that an erroneous determination caused by noise or the like can be effectively prevented.

  Further, according to the motor control device 100 of the present embodiment, the current flowing through the motor M when the motor M is not driven is detected by using the shunt resistor 130 used for detecting the overcurrent when the motor M is driven. Therefore, it is not necessary to add a new configuration to detect the current flowing in the motor M when the motor M is not driven. Therefore, it is possible to easily prevent a malfunction when the motor M is not driven without incurring an increase in cost due to the addition of a new configuration.

<Second embodiment>
In the above-described first embodiment, when the CPU 140 of the motor control device 100 determines that the motor M is malfunctioning according to the polarity of the monitor voltage when the motor M is not driven, it is determined that an abnormality has occurred by the upper CPU (“ An example of the upper-level control device) is described, and when it is determined that the motor M is being rotated from the outside, the upper-level CPU is notified that the motor M is being rotated from the outside. In the present embodiment, a specific example of the operation of the upper CPU receiving such a notification will be described. In the following, the same components as those in the first embodiment are denoted by the same reference numerals, and redundant description will be omitted as appropriate.

  FIG. 7 is a block diagram illustrating a functional configuration example of the host CPU 80 connected to the CPU 140 of the motor control device 100. As shown in FIG. 7, the host CPU 80 includes, as functional components related to the motor control device 100, a host operation command unit 81, a motor operation command unit 82, and a notification receiving unit 83. These functional components are realized, for example, by the host CPU 80 executing a predetermined control program. Note that some or all of these functional components may be realized using dedicated hardware such as an ASIC or FPGA instead of the upper CPU 80 which is a general-purpose processor.

  The configuration of the motor control device 100 is basically the same as that of the first embodiment. However, in the first embodiment, only the behavior when the motor M is not driven, that is, when the motor M is supposed to be in the stopped state and the current is detected to flow through the motor M is described. Here, it is assumed that when an abnormality occurs in the motor M during driving of the motor M, the CPU 140 of the motor control device 100 detects this and notifies the upper CPU 80. The abnormality during the driving of the motor M includes, for example, a motor lock due to a speed abnormality, a start failure that cannot be started according to a start command, and the like. Note that the function of detecting an abnormality during the driving of the motor M and notifying the host CPU 80 of the abnormality is a general function of the motor control device 100, and a detailed description thereof will be omitted.

  The higher-level operation instruction unit 81 outputs an operation instruction to each unit of the image forming apparatus 1 so that the image forming apparatus 1 is in a desired operation state. The higher-level operation instructing means 81 determines whether or not it is necessary to stop the entire operation of the image forming apparatus 1 according to a predetermined criterion, and outputs an abnormal stop instruction if necessary, and outputs an abnormal stop instruction. Stop the whole operation of. In particular, in the present embodiment, based on a flag set in response to the notification receiving unit 83 receiving the notification from the CPU 140 of the motor control device 100, the higher-level operation instruction unit 81 determines the overall operation of the image forming apparatus 1 Determine if it needs to be stopped.

  The motor operation command unit 82 outputs the above-described target speed value and the start / stop command to the CPU 140 of the motor control device 100 in response to the command from the host operation command unit 81.

  The notification receiving unit 83 receives a notification from the CPU 140 of the motor control device 100 and turns on a flag corresponding to the received notification. Specifically, when the notification receiving unit 83 receives a notification indicating an abnormality of the motor M from the CPU 140 of the motor control device 100 during the driving of the motor M, it indicates that an abnormality has occurred during the driving of the motor M. A flag (hereinafter, this flag is referred to as “flag A”) is turned on. When the notification receiving unit 83 receives a notification indicating that an abnormality has occurred from the CPU 140 of the motor control device 100 when the motor M is not driven, the notification receiving unit 83 sets a flag indicating that an abnormality has occurred when the motor M is not driven ( Hereinafter, this flag is referred to as “flag B”). When the motor M is not driven, the notification receiving unit 83 receives a notification from the CPU 140 of the motor control device 100 indicating that the motor M is being rotated from the outside. A flag indicating that it is being turned on from outside (hereinafter, this flag is referred to as "flag C") is turned on.

  The flag A, the flag B, and the flag C are binary (1 bit) information indicating ON / OFF. For example, “1” indicates ON and “0” indicates OFF. These flags are referred to by the higher-level operation instruction unit 81 and the motor operation instruction unit 82 whenever a notification reception event by the notification reception unit 83 occurs.

  When the flag A is turned on while the motor M is being driven, the motor operation command means 82 outputs a command to stop the motor M to the CPU 140 of the motor control device 100. As a result, the operation state management means 141 of the CPU 140 instructs the control signal output means 143 to turn on the brake signal and stops the motor M.

  When the flag A is turned on while the motor M is being driven, or when the flag B is turned on when the motor M is not driven, the upper operation command means 81 outputs an abnormal stop command. The entire operation of the image forming apparatus 1 is stopped. On the other hand, when the flag C is turned on when the motor M is not driven, the higher-level operation command unit 81 continues the entire operation of the image forming apparatus 1 without outputting the abnormal stop command. Here, the entire operation of the image forming apparatus 1 is stopped by, for example, shutting off the power supply to the above-described ADF 1A, the sheet feeding unit 3, the image reading unit 4, and the image forming unit 5 of the apparatus main body 1B. Done by the method. Even when the entire operation of the image forming apparatus 1 is stopped, the power supply to the host CPU 80 and the operation panel is not shut off, and a warning indicating that the operation of the image forming apparatus 1 is stopped due to the occurrence of an abnormality or the like. It is desirable to be able to do.

  The flags A, B, and C, which are turned on by the notification receiving unit 83, are reset from on to off when a predetermined operation by the operator is detected, for example. For example, the flag A and the flag B are reset from on to off when the operator who has performed the recovery from the abnormality performs a predetermined operation using the operation panel. The flag C is reset from on to off when the operator who has performed the jam processing performs a predetermined operation using the operation panel.

  FIG. 8 is a flowchart illustrating an example of a processing sequence executed by the host CPU 80 in response to a notification from the CPU 140 of the motor control device 100. A series of processes shown in the flowchart of FIG. 8 is repeatedly executed by the upper CPU 80 each time the CPU 140 of the motor control device 100 notifies the upper CPU 80.

  When a notification is sent from the CPU 140 of the motor control device 100 to the upper CPU 80, the notification receiving unit 83 receives the notification and turns on a flag corresponding to the received notification (step S201).

  Next, it is determined whether or not the flag turned on by the notification receiving unit 83 in step S201 is the flag A (step S202). When the flag A is turned on (step S202: Yes), the motor operation command unit 82 outputs a command to stop the motor M to the CPU 140 of the motor control device 100 (step S203), and outputs a higher-level operation command. The means 81 outputs an abnormal stop command to stop the entire operation of the image forming apparatus 1 (step S205), and ends a series of processing.

  On the other hand, if the flag turned on by the notification receiving unit 83 in step S201 is not the flag A (step S202: No), it is determined whether the flag is the flag B (step S204). When the flag B is turned on (step S204: Yes), the upper-level operation command unit 81 outputs an abnormal stop command to stop the entire operation of the image forming apparatus 1 (step S205), and a series of processes To end. On the other hand, when the flag turned on by the notification receiving unit 83 in step S201 is not the flag B, that is, when the flag C is turned on (step S204: No), the abnormal operation stop command is not output by the upper operation command unit 81. Then, the process ends.

  As described above, in the present embodiment, when the upper CPU 80 receives a notification indicating that an abnormality has occurred from the CPU 140 of the motor control device 100, the upper CPU 80 outputs an abnormal stop command and performs the entire operation of the image forming apparatus 1. Is stopped, and when a notification indicating that the motor M is being rotated from the outside is received when the motor M is not driven, the entire operation of the image forming apparatus 1 is continued without outputting the abnormal stop command. I have to. Therefore, it is possible to effectively suppress the inconvenience of inadvertently stopping the entire operation of the image forming apparatus 1 when the motor M is externally turned when the motor M is not driven.

  In the above-described first and second embodiments, when it is determined that the motor M is malfunctioning when the motor M is not driven, the CPU 140 of the motor control device 100 responds to a command from the host CPU 80. Instead, the motor M is stopped. However, it was determined that the motor M was malfunctioning when the motor M was not driven, and the notification receiving means 83 of the upper CPU 80 received a notification indicating that an abnormality occurred when the motor M was not driven, and turned on the flag B. In this case, the motor operation command means 82 of the upper CPU 80 outputs a stop command of the motor M to the CPU 140 of the motor control device 100. May be instructed to turn on the brake signal to stop the motor M.

  In the above-described second embodiment, when the host CPU 80 receives a notification from the CPU 140 of the motor control device 100 indicating that an abnormality has occurred when the motor M is not driven, the host CPU 80 outputs an abnormal stop command to perform image formation. The entire operation of the device 1 is stopped. However, the upper CPU 80 outputs an abnormal stop command to stop the entire operation of the image forming apparatus 1 only when receiving a notification indicating that an abnormality has occurred during the driving of the motor M, and When a notification indicating that an abnormality has occurred during driving is received, the entire operation of the image forming apparatus 1 may be continued without outputting an abnormal stop command.

  As mentioned above, although the concrete embodiment of the present invention was explained, the present invention is not limited to the above-mentioned embodiment as it is, and is embodied while adding various modifications without departing from the gist in the implementation stage. be able to. Hereinafter, some modified examples will be exemplified.

(Modification 1)
In the embodiment described above, the current flowing when the motor M is not driven is detected by the shunt resistor 130 connected in series between the motor M and the ground GND. However, the shunt resistor 130 is connected to the motor power supply Vcc and the motor M may be connected. FIG. 9 is a hardware configuration diagram of a modified example in which the shunt resistor 130 is provided on the motor power supply Vcc side. As shown in FIG. 9, even when the shunt resistor 130 is connected in series between the motor power supply Vcc and the motor M, the potential difference between both ends of the shunt resistor 130 is input to the CPU 140 as a monitor voltage. The same effects as in the above-described embodiment can be obtained.

(Modification 2)
In the above-described embodiment, the current flowing when the motor M is not driven is detected by the shunt resistor 130. However, the current flowing when the motor M is not driven may be detected using another type of current detecting means. Good. FIG. 10 is a hardware configuration diagram of a modified example in which a hall sensor 150 is provided instead of the shunt resistor 130. The Hall sensor is a current sensor using a Hall element, which is a magnetoelectric conversion element using the Hall effect. As shown in FIG. 10, even in a configuration in which a Hall sensor 150 is provided instead of the shunt resistor 130, the voltage corresponding to the current detected by the Hall sensor 150 is input to the CPU 140 as a monitor voltage, and The same effect as that of the embodiment can be obtained.

(Modification 3)
In the above-described embodiment, the image forming apparatus 1 configured as an intermediate transfer type tandem-type color copying machine has been described as an example of an image forming apparatus to which the present invention can be applied. It can be widely applied to devices. Further, the present invention can be effectively applied to a sheet feeding device externally connected to the image forming apparatus 1 or the like.

  FIG. 11 is a schematic configuration diagram of a sheet feeding device 200 connected to the image forming apparatus 1. As shown in FIG. 11, the paper feeding device 200 has a configuration in which a paper feeding main body 210 and a relay unit 220 are provided, and a plurality of paper feeding main bodies 210 can be connected in series via the relay unit 220. I have. The paper feed main body 210 transfers the paper selectively removed from the paper feed trays 211 and 212 or the paper from the upstream paper feed main body 210 connected in series via the relay 220 to the transport path P. Along with the image forming apparatus 1 connected to the image forming apparatus 1 via the connection unit 213. The relay unit 220 is connected to the upstream paper supply main unit 210 via the connection unit 221, and conveys the paper supplied from the upstream paper supply main unit 210 to the downstream paper supply main unit 210.

  The sheet feeding device 200 configured as described above conveys a sheet, which is an example of a sheet, by rotating a roller member provided along the conveyance path P with the power of a motor. By applying the present invention to such a sheet feeding device 200, it is possible to easily prevent a malfunction when the motor is not driven, as in the above-described embodiment.

  The present invention can be effectively applied not only to the image forming apparatus 1 and the sheet feeding apparatus 200 but also to various sheet conveying apparatuses configured to convey a sheet by rotating a roller member by the power of a motor. it can. For example, a device that transports banknotes by rotating a roller member with the power of a motor, a device that transports a document by rotating a roller member with the power of a motor, and a ticket or entrance by rotating a roller member with the power of a motor The present invention can be effectively applied to various sheet conveying apparatuses such as an apparatus for conveying a ticket and an apparatus for conveying a resin sheet or a metal plate by rotating a roller member by the power of a motor.

1 image forming apparatus 80 host CPU
81 Higher-level operation instruction means 82 Motor operation instruction means 83 Notification receiving means 100 Motor control device 110 Motor driver 120 Encoder 130 Shunt resistor 140 CPU
141 Operation state management means 142 Control voltage calculation means 143 Control signal output means 144 Voltage polarity determination means 150 Hall sensor 200 Paper feeder M Motor

Japanese Patent No. 3888969

Claims (19)

Current detection means for detecting a current flowing through the motor when the motor is not driven;
Voltage polarity determining means for determining the polarity of the voltage corresponding to the detected current,
An operation state management unit that performs control to stop the motor in accordance with the polarity of the voltage. When the polarity of the voltage corresponding to the current flowing from the power supply to the ground through the motor is plus,
The motor control device according to claim 1, wherein the operation state management unit performs control to stop the motor when the polarity of the voltage is positive.   The motor control device according to claim 1, wherein the operation state management unit notifies the host control device that an abnormality has occurred when the motor is stopped.   3. The motor control device according to claim 2, wherein when the polarity of the voltage is negative, the operation state management unit notifies the host control device that the motor is being rotated from outside. 4.   The motor control device according to any one of claims 1 to 4, wherein the voltage polarity determination unit determines the polarity of the voltage when the value of the voltage exceeds a reference value. A drive signal corresponding to a control voltage applied to the motor, and a control signal output unit that outputs a brake signal for stopping the motor,
A motor driver that drives the motor based on the drive signal, and shuts off the power supply to the motor when the brake signal is ON.
6. The motor control device according to claim 1, wherein the operation state management unit stops the motor by instructing the control signal output unit to turn on the brake signal. 7. . The motor driver has a terminal for inputting the drive signal, a terminal for inputting the brake signal, and a terminal for inputting a start / stop signal. When the start / stop signal is on the start side, Driving the motor based on the input driving signal,
A terminal for inputting the drive signal and a terminal for inputting the brake signal are respectively connected to the control signal output means via a harness,
The motor control device according to claim 6, wherein an output of the terminal for inputting the start / stop signal is fixed to a start side.   The motor control device according to claim 7, wherein the terminal for inputting the brake signal is fixed to a side where the brake signal is turned on when an abnormality occurs in a harness connecting the terminal and the control signal output means. .   The motor control device according to any one of claims 1 to 8, wherein the current detection unit is a shunt resistor used for detecting an overcurrent when the motor is driven. Current detection means for detecting a current flowing through the motor when the motor is not driven;
A motor control device comprising: a voltage polarity determination unit configured to determine whether the motor is malfunctioning based on a polarity of a voltage corresponding to the detected current. A motor control device according to any one of claims 1 to 10,
Said motor;
A roller member configured to rotate the sheet by a power of the motor to convey the sheet. A sheet conveying device according to claim 11,
An image forming apparatus comprising: an image forming unit that forms an image on the conveyed sheet. A motor, a motor control device, and a higher-level control device, comprising an image forming apparatus,
The motor control device,
Current detection means for detecting a current flowing through the motor when the motor is not driven;
Based on the polarity of the voltage corresponding to the detected current, voltage polarity determining means for determining whether the motor is malfunctioning,
When it is determined that the motor is malfunctioning, it notifies the host controller that an abnormality has occurred, and when it is determined that the motor is not malfunctioning, the motor is turned from outside. Operating state management means for notifying the higher-level control device that the
The higher-level control device,
When the operation state management unit notifies that an abnormality has occurred, the operation state management unit outputs an abnormal stop command to stop the entire operation of the image forming apparatus, and the operation state management unit externally rotates the motor. An image forming apparatus, comprising: a higher-level operation instruction unit that continues the operation of the image forming apparatus without outputting the abnormal stop instruction when the notification is made.   The image forming apparatus according to claim 13, wherein the operation state management unit performs control to stop the motor when it is determined that the motor is malfunctioning. The higher-level control device,
Further provided is a motor operation command unit that outputs a motor stop command to the operation state management unit when notified that an abnormality has occurred from the operation state management unit,
The image forming apparatus according to claim 14, wherein the operation state management unit performs control to stop the motor in response to the stop command output from the motor operation command unit. A motor, a motor control device, a higher-level control device, a sheet conveying device including:
The motor control device,
Current detection means for detecting a current flowing through the motor when the motor is not driven;
Based on the polarity of the voltage corresponding to the detected current, voltage polarity determining means for determining whether the motor is malfunctioning,
When it is determined that the motor is malfunctioning, it notifies the host controller that an abnormality has occurred, and when it is determined that the motor is not malfunctioning, the motor is turned from outside. Operating state management means for notifying the higher-level control device that the
The higher-level control device,
If the operation state management unit is notified that an abnormality has occurred, the operation state management unit outputs an abnormal stop command to stop the entire operation of the sheet conveyance device, and the operation state management unit externally rotates the motor. A sheet transport device that includes a higher-level operation command unit that continues the operation of the sheet transport device without outputting the abnormal stop command when notified that the sheet transport device is not operating.   The sheet conveying device according to claim 16, wherein the operation state management unit performs control to stop the motor when it is determined that the motor is malfunctioning. The higher-level control device,
Further provided is a motor operation command unit that outputs a motor stop command to the operation state management unit when notified that an abnormality has occurred from the operation state management unit,
18. The sheet conveying device according to claim 17, wherein the operation state management unit controls the motor to stop according to the stop command output from the motor operation command unit. A motor control method executed by a motor control device,
Detecting a current flowing through the motor when the motor is not driven;
Determining the polarity of the voltage corresponding to the detected current;
Controlling the motor to stop according to the polarity of the voltage.

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