JP6641785B2 - Motor overload abnormality detection device, motor drive control device, image forming apparatus, and motor overload abnormality detection method - Google Patents

Description

  The present invention relates to a motor overload abnormality detection device, a motor drive control device, an image forming apparatus, and a motor overload abnormality detection method.

  Motors are frequently used as driving sources for various devices. The motor must be used with care for the winding temperature rise. If the motor operating conditions are out of the range of the expected operating conditions and the motor is overloaded, it is known that the winding temperature will rise and the motor may be damaged, or the temperature may exceed the safety standard. I have.

In order to cope with this problem, the operation of the motor is stopped by detecting an overload state of the motor, the duty of the motor driving voltage is reduced, and the substantial motor driving current is reduced.
For example, in Patent Document 1, when it is determined that the motor is in an overload state, the rotation speed of the motor is reduced to a predetermined speed, and when it is determined that the motor is in a more dangerous overcurrent state, the motor is stopped for a predetermined time. It is disclosed that the rotation of is stopped.

However, in such a conventional method, when the overload detection of the motor is performed to suppress an increase in the winding temperature, the operation is performed when the drive current of the motor or the voltage instruction value to the motor exceeds a certain threshold value. The motor was stopped or the motor drive current was limited. Therefore, there is a problem that the motor is detected as abnormal before the actual winding temperature of the motor does not satisfy the temperature standard.
In order to reduce downtime when the user cannot use the device, it is desirable to continue the operation of the motor as far as possible within the operable range. However, the downtime is prolonged by stopping the motor immediately after detecting the overload or by unnecessarily restricting the motor drive current.

  The present invention has been made to solve such a problem, and continues to drive the motor to near the limit of the usable condition while detecting an abnormality so that the motor is not damaged or exceeds the temperature specification value. An object of the present invention is to reduce downtime of equipment using a motor by making it possible.

In order to achieve the above object, a motor overload abnormality detecting device according to the present invention detects a motor overload abnormality based on a motor drive instruction value calculated according to a motor rotation speed, and responds to the detection result. A motor overload abnormality detection device that outputs a motor drive instruction value,
A moving average value for acquiring a motor drive instruction value calculated according to the rotation speed of the motor for each section of a fixed time and calculating a moving average value of the motor drive instruction value for a predetermined number of sections including the latest section. Calculating means, comparing the moving average value calculated by the moving average value calculating means with a preset threshold value to determine the presence or absence of an overload abnormality, and determining that the overload abnormality does not occur. In this case, a motor drive instruction value corresponding to the motor drive instruction value calculated according to the rotation speed of the motor is output. If the determination means determines that there is an overload abnormality, the output motor drive instruction value is output. possess the indicated value switching means for switching the zero or the computed value lower than the motor driving instruction value, the instruction value switching means, when said determination means determines an overload there is an abnormality, the motor can be stopped motor If not, the motor drive instruction value corresponding to the motor drive instruction value calculated according to the rotation speed of the motor is output, and the number of sections where the state is continued is counted, and the motor stop timing is determined. After that, the motor drive instruction value to be output is switched to zero or a value lower than the calculated motor drive instruction value only for the counted number of sections .

  ADVANTAGE OF THE INVENTION According to this invention, while performing abnormality detection so that a motor may not be damaged or a temperature specification value is not exceeded, the drive of a motor can be continued to the vicinity of the limit of usable conditions, and the downtime of the motor using equipment is shortened can do.

1 is an overall view illustrating a schematic configuration of an embodiment of a motor drive control device according to the present invention and an image forming apparatus including a motor driven by the motor drive control device. FIG. 2 is a perspective view illustrating an example of a transport roller and a driving unit thereof in a paper feed / transport mechanism 21 in the image forming apparatus illustrated in FIG. 1. 1 is a block diagram illustrating a configuration of an embodiment of a motor overload abnormality detection device and a motor drive control device according to the present invention. FIG. 9 is a block diagram showing a configuration of another embodiment of a motor overload abnormality detection device and a motor drive control device according to the present invention. FIG. 7 is a diagram showing a transition of a winding temperature rise of a motor when a constant torque instruction value is given. FIG. 3 is a diagram for explaining parameters such as a threshold value and a torque average value used in the present invention. FIG. 4 is a diagram illustrating an operation example of a motor overload abnormality detection unit 40 shown in FIG. 3. 8 is a flowchart of a main routine of a process performed by a motor overload abnormality detection unit 40 in FIG. 3 to realize the operation illustrated in FIG. 9 is a flowchart of a subroutine of step S2 (overload determination processing) in FIG. FIG. 4 is a diagram for explaining another operation example of the motor overload abnormality detection unit 40 shown in FIG. 3. 11 is a flowchart of a main routine of a process performed by a motor overload abnormality detection unit 40 in FIG. 3 to realize the operation illustrated in FIG. It is a flowchart of the subroutine of step S2 '(overload determination processing) in FIG. 9 is a flowchart of a main routine in which a process for notifying an overload state is added to the motor overload abnormality detection operation shown in FIG. 12 is a flowchart of a main routine in which a process for notifying an overload state is added to the motor overload abnormality detection operation shown in FIG.

Hereinafter, embodiments for carrying out the present invention will be specifically described with reference to the drawings.
[Embodiment of image forming apparatus]
FIG. 1 is an overall view showing a schematic configuration of an embodiment of an image forming apparatus provided with a motor driven by a motor drive control device according to the present invention.
This image forming apparatus is a digital multifunction peripheral that realizes a plurality of functions such as a color copier, a scanner, and a color printer, and includes an image forming unit (printer unit) 1, a paper feeding unit 2, an image reading unit (scanner unit). 3 and an automatic document feeder (abbreviated as "ADF") 4 and the like.
A paper discharge tray 5 is provided on one side of the image forming unit 1, and a manual feed tray 6 for inserting a manual feed document is provided on the other side.

An image forming unit 10 including four image forming units for forming a color image, an image writing unit 14, an intermediate transfer belt 15, a pair of positioning rollers 16, a secondary transfer roller 17, A transport belt 18, a fixing device 19, and the like are provided.
The image forming unit 10 includes four intermediate image forming units for forming four color toner images of yellow (Y), magenta (M), cyan (C), and black (Bk). The transfer belt 15 is disposed along the moving direction. Each of the image forming units includes a photosensitive drum 11 and a charging roller 12 and a developing device 13 arranged around the photosensitive drum 11.
The image forming unit for each color differs only in the color of the toner stored in the developing device 13 from yellow, magenta, cyan, and black.

The paper supply unit 2 includes a four-stage paper cassette 20 for storing transfer papers (recording media and paper) of four types and sizes, and a transfer paper housed in each paper cassette 20. A paper feed / transport mechanism 21 is provided for sequentially feeding the paper and transporting the paper to the image forming section 1.
The paper feed / transport mechanism 21 is provided with a number of paper feed rollers and transport rollers, each of which is driven to rotate by a motor.

The image forming apparatus also includes a controller for performing sequence control of an image forming operation and the like, a power supply for supplying power to each unit, and the like. Further, each photosensitive drum 11, a driving roller for the intermediate transfer belt 15, a pair of positioning rollers 16, a driving roller for the transport belt 18, each roller in the fixing device 19, a paper feed roller and a transport roller for the paper feed / transport mechanism 21, etc. And a motor drive control circuit for driving each motor.
At an easily visible position outside the image forming apparatus, there is provided an operation panel on which a user inputs selection of various functions, operation instructions, and the like, and displays a state of the apparatus, for example, an overload abnormality or a forced motor stop described later. ing.

Here, the operation when the image forming apparatus functions as a copying machine will be briefly described.
When the user sets a document to be copied on the ADF 4 or opens the ADF 4 and places the document on the contact glass of the image reading unit 3, closes the ADF 4 and presses a start button on the operation panel, the image formation is started. The apparatus starts a copying operation.

  When a document is set on the ADF 4, the ADF 4 conveys the document one by one through the document reading position of the image reading unit 3. Then, the image reading section 3 scans the document while irradiating the document with light, and reads the image by a CCD line sensor for color reading by reflected light from the document. When a document is placed on the contact glass, the image reading unit 3 scans the document while irradiating the document with light, and similarly reads the image of the document.

The image data read by the CCD line sensor is subjected to image processing such as scanner γ correction, color conversion from three colors of RGB to four colors of YMCBk, image separation, and gradation correction by an image processing unit of the image reading unit 3. It is sent to the image writing unit 14 of the forming section 1.
The image writing unit 14 modulates the driving of the LD (laser diode) for each color according to the image data of the four colors YMCBk.

The outer peripheral surface of the image forming unit for each color of the image forming unit 10 is uniformly charged by the charging roller 12 while the respective photosensitive drums 11 rotate leftward in FIG. Exposure scan is performed by a laser beam, and an electrostatic latent image is written.
The electrostatic latent image is visualized by attaching the toner of each color by each developing unit 13, and a toner image of each color is formed on the outer peripheral surface of each photosensitive drum 11. The toner images of the respective colors are sequentially transferred onto the intermediate transfer belt 15 in the primary transfer section at a predetermined timing, so that a full-color toner image is formed.

In the meantime, the transfer paper selected according to the size of the document is conveyed to the image forming unit 1 from one of the paper supply cassettes 20 of the paper supply unit 2 by the paper supply / conveyance mechanism 21 and the transfer paper of the transfer paper is selected. It is stopped in a state where the tip has reached the positioning roller pair 16.
Then, at the timing when the full-color toner image on the intermediate transfer belt 15 reaches the secondary transfer portion facing the secondary transfer roller 17, the positioning roller pair 16 is activated to feed the transfer paper to the secondary transfer portion. And collectively transfer the full-color toner image onto the transfer paper.

The transfer paper on which the full-color toner image has been transferred is sent to a fixing device 19 by a transport belt 18, where the toner image is thermally fixed by a fixing roller and a pressure roller, and then discharged onto a discharge tray 5. .
When forming a black and white image, the image forming section 1 operates only the black image forming unit of the image forming section 10 to form a black and white image.

When the image forming apparatus functions as a printer, print data transmitted from a host device such as a personal computer is received by the image forming apparatus, and based on the print data, the image forming unit 1 operates in the same manner as described above. Create a color or black and white image.
When operating this image forming apparatus as a scanner, only the image reading unit 3 and the ADF 4 are operated to read an image of a document, store the image data in an internal memory, and, if necessary, use an external personal computer. Etc. to the host device.

FIG. 2 is a perspective view showing an example of a transport roller and a drive unit thereof in the paper feed / transport mechanism 21 in the image forming apparatus shown in FIG.
2, the rotational force of the motor 22 is transmitted by the meshing of the small gear 23 and the spur gear 24, and is rotated in the arrow A direction. A driven roller 26 is rotatably provided in parallel with the transport roller 25 so that the outer peripheral surfaces thereof partially contact each other. The transfer paper P, which is a recording medium, is sandwiched between the nip portion between the transport roller 25 and the driven roller 26, and is transported in the direction of arrow B.
The paper feed / transport mechanism 21 is provided with a large number of such transport rollers 25, and the motor 22 for driving each of the transport rollers 25 is driven and controlled by a motor drive control device described later according to the present invention.

The image forming apparatus to which the present invention is applied is not limited to the color MFP described in the above embodiment, but may be a single-function image forming apparatus such as a copying machine, a printer, a facsimile machine, or a monochrome image forming apparatus. Also in the case of color, the color need not be full color, and the invention is not limited to the tandem system or the intermediate transfer system.
Further, the motor overload abnormality detection device and the motor drive control device according to the present invention described below are applicable not only to the image forming apparatus but also to various apparatuses having members driven and rotated by a motor.

[Configuration example of motor overload abnormality detection device and motor drive control device]
FIG. 3 is a block diagram showing a configuration of an embodiment of a motor overload abnormality detection device and a motor drive control device according to the present invention.
The motor drive control device includes an encoder 35 that is a speed detection unit that detects a rotation speed of the motor M, a motor control unit 32, and a motor drive circuit 33 that drives the motor M under the control of the motor control unit 32. ing. The motor control unit 31 is constituted by the motor control unit 32 and the motor drive circuit 33.

The motor control unit 32 of this embodiment includes an instruction value calculation unit 36, a PWM conversion unit 37, and a motor overload abnormality detection unit 40. The motor overload abnormality detection unit 40 includes a moving average value calculation unit 41, And a command value switching unit 43. The motor overload abnormality detection section 40 is an embodiment of the motor overload abnormality detection device according to the present invention.
The motor M is, for example, the motor 22 that rotationally drives the transport roller 25 shown in FIG.

The main control unit 30 starts and stops (START / STOP) the motor M by the motor drive control unit 31 and controls the entire image forming apparatus including the motor drive control unit 31 and the motor M (controller). ).
When a start signal (motor START signal) is sent from the main control unit 30 to the motor control unit 32 of the motor drive control unit 31, the motor control unit 32 starts starting the motor M.
After the activation of the motor M, the current rotational speed of the motor M is detected by the encoder 35 and is fed back to the motor control unit 32.

The instruction value calculation unit 36 compares the fed-back rotation speed with the target speed, and increases the torque instruction value when the rotation speed is lower than the target speed, and decreases the torque instruction value when the rotation speed is higher than the target speed. Calculate and output the value. The torque instruction value is a motor drive instruction value, and corresponds to a voltage instruction value for the motor M. The target speed is stored in the motor control unit 32 or instructed by the main control unit 30.
In the case of a general motor drive control circuit in which the motor control unit does not include the motor overload abnormality detection unit, the torque instruction value (or the voltage instruction value) output from the instruction value calculation unit 36 is directly input to the PWM conversion unit 37. Is converted to a PWM instruction value.

By controlling ON / OFF of the six drivers (FETs in the illustrated example) S1 to S6 of the motor drive circuit 33 in the motor drive control unit 31 with the PWM instruction values, the winding of the motor M is controlled. , A three-phase (U, V, W phase) drive voltage is applied to the stator coil. As a result, a drive current sequentially flows through the two phases of the stator coil, and the motor M rotates.
The rotation speed of the motor M is detected by the encoder 35 and fed back to the motor control unit 32. In this manner, the drive voltage of the motor M changes according to the actual rotation speed of the motor M, feedback control is performed, and the motor M is rotated at a constant target speed. Each driver of the motor drive circuit 33 may be a bipolar transistor.

  This motor drive circuit 33 is also called an inverter circuit, and connects three sets of drivers S1 and S2, S3 and S4, S5 and S6, which are connected in series two by two, between a DC power supply VDD and the ground in parallel. I have. The connection points of the two drivers are connected to the open ends of the three star-connected stator coils of the motor M, respectively. R1 is a protection resistor inserted between the motor drive circuit 33 and the ground.

  As described above, in the motor drive control device in which the rotation speed of the motor M is detected by the encoder 35 serving as the speed detection means and the rotation speed is controlled to be a constant target speed, the rotation speed is reduced due to a large load. If this happens, increase the motor drive instruction value. As a result, the drive current flowing through the motor M is increased. However, if the motor drive instruction value (torque instruction value or voltage instruction value) is too large, the winding temperature of the motor M rises, and the motor smokes or breaks. Or you may. In order to prevent this, it is necessary to provide a means for detecting an overload state of the motor, limiting the motor drive instruction value, and limiting an increase in drive current.

In the motor drive control device of this embodiment, a motor overload abnormality detection unit 40 is provided in the motor control unit 32 for that purpose.
The motor overload abnormality detection unit 40 detects the motor winding temperature for each fixed time section of a motor drive instruction value (torque instruction value or voltage instruction value) calculated according to the detected value of the rotation speed of the motor M. Is estimated on the basis of the moving average value of the calculated value, and the presence or absence of a motor overload abnormality is determined. When it is determined that the motor is overloaded, the motor is stopped or the drive current is reduced only in the next section. This prevents the motor from stopping unnecessarily or increasing the intermittent time, so that the motor can be driven to near the limit of the usable condition.

Therefore, the function of the motor overload abnormality detection unit 40 will be described in more detail.
Based on the rotation speed of the motor M, the torque instruction value calculated by the instruction value calculation unit 36 is input to the motor overload abnormality detection unit 40 to determine overload, and the voltage instruction value is switched based on the determination result. Output to the PWM converter 37. As described above, the torque command value and the voltage command value are both motor drive command values and correspond to each other. In the following description, the motor drive instruction value input to the motor overload abnormality detection unit 40 will be referred to as a torque instruction value, and the motor drive instruction value output from the motor overload abnormality detection unit 40 will be distinguished as a voltage instruction value.

The motor overload abnormality detection unit 40 includes a moving average value calculation unit 41, a determination unit 42, and an instruction value switching unit 43. The moving average value calculation unit 41 is a moving average value calculation unit, the determination unit 42 is a determination unit, and the instruction value switching unit 43 is an instruction value switching unit.
The moving average value calculation unit 41 obtains a torque instruction value, which is a calculation result of the instruction value calculation unit 36, for each section of a fixed time, and calculates a moving average value of the torque instruction value for a preset number of sections up to the latest section. Is calculated. The details will be described later.
The determination unit 42 compares the moving average value of the torque instruction value calculated by the moving average value calculation unit 41 with a preset threshold to determine whether there is an overload abnormality. The threshold value will also be described later.

When the determination unit 42 determines that there is no overload abnormality, the instruction value switching unit 43 outputs the voltage instruction value corresponding to the torque instruction value input from the instruction value calculation unit 36 as it is, and determines that there is an overload abnormality. In this case, the voltage instruction value is switched to, for example, zero (0) and output. However, without switching to zero, the voltage command value corresponding to the torque command value input from the command value calculation unit 36 is reduced at a predetermined ratio such as, for example, １ ／, or a constant value lower than the voltage command value. You may switch to a smaller value.
When the determination unit 42 determines that there is an abnormality, the main control unit 30 can be notified that an overload abnormality has occurred.

The voltage command value output from the command value switching unit 43 of the motor overload abnormality detection unit 40 is input to the PWM conversion unit 37 and is converted into a PWM command value. The motor M is driven by controlling ON / OFF of the six drivers S1 to S6 of the motor drive circuit 33 according to the PWM instruction value.
In this embodiment, the main control unit 30 and the motor control unit 32 are configured separately, and each has a microcomputer including a CPU, a ROM, a RAM, and the like. However, the main control unit 30 and the motor control unit 32 may be configured as an integrated control unit that operates on the same microcomputer (CPU).
The PWM conversion unit 37 is a unit that controls the motor drive circuit 33 according to the voltage instruction value output from the instruction value switching unit 43 of the motor overload abnormality detection unit 40. This means is not limited to the PWM conversion unit, but may be a PFM conversion unit or another conversion circuit.

FIG. 4 is a block diagram showing a configuration of another embodiment of the motor overload abnormality detection device and the motor drive control device according to the present invention.
The motor drive control device shown in FIG. 4 is different from the motor drive control device shown in FIG. 3 in that the motor drive control device includes a motor drive current detection unit 38 for detecting the drive current of the motor M. This is the point that the detected value is also input to the motor overload abnormality detecting section 40 '. In this embodiment, the protection resistor R1 in FIG. The voltage generated in proportion to the value of the current flowing through the resistor R1 is input to the motor overload abnormality detection unit 40 'of the motor control unit 32 as the detection value of the motor drive current (motor drive current value).
The motor overload abnormality detection section 40 'is the motor overload abnormality detection device in this embodiment.

The moving average value calculation unit 41 'of the motor overload abnormality detection unit 40' A / D converts the motor drive current value detected by the motor drive current detection unit 38 and captures the value at regular intervals (time intervals). To save. Then, a moving average value of the motor drive current value in a preset number of sections up to the latest section is calculated.
The determining unit 42 'determines whether there is an overload abnormality by comparing the moving average value of the motor drive current calculated by the moving average value calculating unit 41' with a preset threshold value.

When the determination unit 42 'determines that there is no overload abnormality, the instruction value switching unit 43 outputs the voltage instruction value corresponding to the torque instruction value input from the instruction value calculation unit 36 as it is, and determines that there is an abnormality. In this case, the voltage indication value is switched to, for example, zero (0) and output. Other switching examples are the same as those described for the instruction value switching unit 43 of the motor overload abnormality detection unit 40 in FIG. The same applies to other modified examples.
Although the configuration of the motor drive control unit 31 and the motor control unit 32 in FIG. 4 is slightly different from the configuration of the motor drive control unit 31 and the motor control unit 32 shown in FIG. The same reference numerals are given.

[Operation example of motor overload abnormality detection unit]
Hereinafter, an operation example of the motor overload abnormality detection unit 40 illustrated in FIG. 3 will be described with reference to FIGS.
FIG. 5 is a diagram showing a transition of the winding temperature rise of the motor when a fixed torque instruction value is given. The horizontal axis in FIG. 5 indicates the elapsed time from the start of the motor, and the vertical axis indicates the torque instruction value (voltage instruction value) and the winding temperature.

In this example, a constant torque instruction value A shown by a thick line is continuously given to the PWM conversion unit 37 shown in FIG. The temperature rise of the winding at this time becomes a rising curve as shown by the curve, and finally becomes constant at X ° C.
This is also evident from Equation 1 for general temperature rise.
[Equation 1]
Temperature rise = heat transport amount (heat flow rate) [W] · R · {1-exp} -t / (RC)}
(R: thermal resistance (° C / W) C: thermal capacity (J / ° C) t: time (S))

The characteristic of the temperature rise expressed by the above equation 1 will be briefly described.
When the winding temperature of the motor is low, the temperature difference from the ambient temperature is small, and the heat flow released to the surroundings is small, so that the winding temperature rises steadily. However, as the temperature of the windings rises, the temperature difference from the ambient temperature increases and the heat flow released to the surroundings increases, so the amount of heat finally given to the windings and the amount of heat released to the surroundings are balanced. At this point, the winding temperature becomes constant.

FIG. 6 is a diagram for explaining parameters such as a threshold value and a torque average value used in the present invention. The horizontal axis indicates the elapsed time from the start of the motor, and the vertical axis indicates the torque average value (voltage average value), which is the average value of the torque instruction value (voltage instruction value) for each section, and the winding temperature.
FIG. 6A shows the average torque value at the maximum load under the normal use condition. When the torque average value A continues, the temperature at which the winding temperature of the motor becomes finally constant is defined as Z ° C. based on Equation 1. On the other hand, the temperature that must not be exceeded is W ° C. due to safety standard values, winding specifications, and the like.

Here, the threshold values A and B of the average torque value, the temperature W ° C., and the average value ΔU of the torque instruction value, which are premise of the present invention, will be described.
First, the threshold value B is set in a range where the temperature does not reach W ° C. from Z ° C. within the time ΔT. This state is a value exceeding the torque instruction value A (threshold value A) at the maximum load under the normal use condition, and if it exceeds the threshold value B on average, it indicates an overload state.
In each section of ΔT, the torque instruction value in the section is accumulated and divided by the cumulative number to obtain a torque average value ΔU (ΔU1, ΔU2, ΔU3,...) Which is the average value of the torque instruction values. , ΔUm, ΔUm + 1,...).

The reason for taking the section average value of ΔT without taking the instantaneous value of the torque command value in each section data is that the torque command value corresponding to the voltage command value to the motor has a large instantaneous variation, May not be determined correctly.
Further, when the situation where the torque average value ΔU, which is the average value of the torque instruction values in the section, becomes the threshold value B from the state where the winding temperature is Z ° C. continues, the time until the temperature becomes W ° C. is set in advance. Derived.
When the heat flow rate, the heat resistance, and the heat capacity are known, the time t can be obtained from the above equation (1). If those parameters are not known, the time t is obtained by temperature measurement.

FIG. 7 is a diagram for explaining an operation example of the motor overload abnormality detecting section 40 shown in FIG. 3, and shows a transition of the torque average value (voltage average value) ΔU and the winding temperature.
This is performed by the motor overload abnormality detection section 40 of the motor control section 32 shown in FIG.
First, the motor overload abnormality detection unit 40 acquires the torque average value (voltage average value) ΔU described in FIG. The acquisition of the torque average value ΔU is performed by the moving average value calculation unit 41.

  From the start of the motor M, the instruction value calculation unit 36 calculates a torque instruction value for the motor M based on the rotation speed of the motor M detected by the encoder 35 as the speed detection means shown in FIG. It is input to the load abnormality detection unit 40. The moving average value calculation unit 41 receives the torque instruction value, calculates a torque average value ΔU which is an average value of the torque instruction values in the section at each time ΔT, and sequentially stores the calculated torque average value in a storage buffer for each section. Store.

Then, a moving average value of the average value ΔU stored in the storage buffer is calculated. For example, when the acquired data of the torque average value in the latest section is ΔUm, a moving average for a predetermined number of sections up to the latest section is obtained. Here, an example in which a moving average value for four sections is obtained is shown, and the moving average value Um is calculated by (ΔUm + ΔUm−1 + ΔUm−2 + Um−3) / 4.
For each calculation, the determination unit 42 compares the moving average value Um + α with the threshold B to determine whether there is an abnormality due to overload.

  When the determination unit 42 determines that the moving average value Um + α does not exceed the threshold value B (there is no overload abnormality), the voltage corresponding to the torque instruction value input from the instruction value calculation unit 36 by the instruction value switching unit 43 Directly outputs the indicated value. When the determination unit 42 determines that the moving average value Um + α has exceeded the threshold value B (there is an overload abnormality), the voltage instruction value is switched to 0 and output. That is, the motor M is stopped as an intermittent section in the next section of the ΔT time.

Then, the moving average value (Um + 1, Um + 2, Um + 3,...) Of the torque average value for each of the four sections is calculated continuously, including ΔT during the stopped period, and the moving average value Um + α is set to the threshold value B. When the voltage falls below the threshold value, the voltage instruction value is output again to drive the motor M.
In the case of FIG. 7, the moving average values Um + 1, Um + 4, and Um + 6 exceed the threshold value B, and the motor is stopped in the next section.

By doing so, the winding temperature changes in a saw-tooth waveform indicated by the solid curve in FIG. 7, and even when the moving average value exceeds the threshold value B, the winding temperature does not exceed the standard value and the specification. The driving of the motor can be continued. The dotted line curve shows a winding temperature rise curve when the torque average value maintains the threshold value B.
The detailed control process will be described with reference to the flowcharts of FIGS.

[Explanation of flowchart for realizing operation of FIG. 7]
8 and 9 are flowcharts of processing by the motor overload abnormality detection unit 40 in FIG. 3 for realizing the operation shown in FIG. FIG. 8 is a main routine, and FIG. 9 is a subroutine of step S2 (overload determination processing) in FIG.
The processing shown in this flowchart functions as a moving average value calculation unit 41, a determination unit 42, and an instruction value switching unit 43 of the motor overload abnormality detection unit 40 by using the microcomputer provided in the motor control unit 32 shown in FIG. This is a process by a program for causing the program to execute. In the following description, the microcomputer is abbreviated as “CPU”.

When the power of the image forming apparatus is turned on, the CPU starts the processing of the main routine in FIG. 8, and first determines in step S1 whether the motor is being started. This is because a motor start (START) signal is input from the main control unit 30 to the motor control unit 32 shown in FIG. 3 to start the motor M, or a motor stop (STOP) signal is input to stop the motor M. Judge whether to do.
The motor start-up process by the motor control unit 32 is the same as the conventional one, so that the description is omitted. When the CPU determines in step S1 that the motor is being started, the CPU executes an overload determination process shown in FIG. 9 in step S2.

In this overload determination processing, the CPU first determines in step S201 whether or not Ta = Tx (time ΔT has elapsed). Ta is a count value of a time measurement counter for measuring the time ΔT of each section shown in FIG. 7, and Tx is a count value (Tx = ΔT) corresponding to the time ΔT of one section.
At first, Ta = Tx is not satisfied, so the CPU determines NO and proceeds to step S202, in which the accumulated torque Ua (initially 0) of the torque command value input from the command value calculation unit 36 is set to the current torque command. The values are added to form a new accumulated value Ua. Then, in step S203, the time measurement counter is counted up, the count value Ta is incremented by 1, and the process returns to step S201. Until the CPU determines in step S201 that Ta = Tx, the processes in S202 and S203 are repeated, and the torque instruction value for each time is cumulatively added for one section.

When the CPU determines in step S201 that Ta = Tx, the time ΔT of one section has elapsed, so the flow proceeds to step S204 to calculate ΔU = Ua / Tx. This calculation is to divide the cumulative value Ua of the torque instruction value by the count value Tx corresponding to the time ΔT of this section to obtain an average torque value ΔU of this section.
Then, in step S205, the CPU stores the torque average value ΔU obtained in step S204 in the storage buffer ΔUm, and in step S206, counts up the storage buffer counter, and sets the count value m to m + 1.

Next, in step S207, the CPU calculates a moving average value of the average value ΔU of the torque instruction values stored in the storage buffer for the predetermined section including the current section. The number of sections is determined in advance at the time of designing the apparatus and set in a memory.
For example, if the current torque average value stored in the latest storage buffer is ΔUm and the moving average value for the four sections up to that is determined, as shown in parentheses in step S207,
(ΔUm + ΔUm−1 + ΔUm−2 + ΔUm−3) / 4
To calculate the moving average value Um of the torque average value ΔU.

The moving average value in the initial stage immediately after the motor is started is obtained by the following calculation in the case of the four-section moving average.
In the first section, the other three sections are set to 0, and (ΔUm + 0 + 0 + 0) / 4 is calculated. In the third section, the calculation of (ΔUm + ΔUm−1 + ΔUm−2 + 0) / 4 is performed assuming that the third section is 0. As described above, in the section before the motor is started, the calculation is performed with the torque average value set to “0”.
The processing up to this point corresponds to the function or procedure of the moving average value calculation unit 41 in FIG.

Thereafter, in step S208, the CPU determines whether or not the moving average value Um calculated this time has exceeded the threshold value B shown in FIG. As a result, when the CPU determines that the moving average value Um has exceeded the threshold value B (there is an overload abnormality), the CPU sets an intermittent stop flag in step S209. If the CPU determines that the moving average value Um does not exceed the threshold value B (no overload abnormality), the CPU clears the intermittent stop flag in step S210.
The processing of steps S208 to S210 is processing corresponding to the function or procedure of the determination unit 42 shown in FIG.

In any case, in the next step S211, the count value Ta of the time measurement counter and the accumulated value Ua of the torque instruction value are cleared to 0, and the process returns to the main routine of FIG.
The number of sections (time) in which the moving average of the torque average value ΔU is obtained is such that the winding temperature of the motor M does not reach W ° C. from Z ° C. shown in FIG. Set in the range.
The number of sections for calculating the moving average value is set in advance, but may be changed thereafter. For example, after the image forming apparatus is used, a service person may be able to change the setting according to installation conditions, usage conditions, and the like.

  When the CPU returns to the process of the flowchart of FIG. 8, it is determined in step S3 whether the intermittent stop flag is set. As a result, if the intermittent stop flag is set, the voltage instruction value to the motor is set to 0 regardless of the torque instruction value from the instruction value calculation unit 36 in step S4. If the intermittent stop flag is not set, a value corresponding to the torque command value from the command value calculation unit 36 is set as the voltage command value to the motor in step S5. The processing of steps S3 to S5 is processing corresponding to the function or procedure of the instruction value switching unit 43 shown in FIG.

If the CPU determines in step S1 that the motor is not being started (stopped), the intermittent stop flag is cleared in step S6. Further, in step S7, the count value Ta of the time measurement counter and the accumulated value Ua of the torque instruction value are cleared to 0, and in step S8, all buffers ΔUm and the like are cleared to 0.
After performing the processing of steps S4, S5, and S8, the CPU returns to step S1 and repeats the processing described above.

In this way, the voltage instruction value set by the CPU is output from the instruction value switching unit 43 of the motor overload abnormality detection unit 40 to the PWM conversion unit 37, where it is converted into a PWM instruction value to control the motor drive circuit 33. , And drives the motor M.
As a result, the operation described with reference to FIG. 7 can be realized, and the drive of the motor can be continued to near the limit of the usable condition within a range not exceeding the standard value and the specification of the temperature.

[Other operation examples of the motor overload abnormality detection unit]
Another operation example of the motor overload abnormality detecting section shown in FIG. 3 will be described with reference to FIGS.
In the above-described operation example, when the moving average value Um + α of the torque average value in the predetermined section number exceeds the threshold value B, the voltage instruction value to the motor in the next section is set to 0 and the intermittent stop section is set. However, depending on the condition of use of the motor whose drive is controlled by the motor drive control device, it may be possible that the motor cannot be stopped intermittently immediately. For example, in the case of a motor that rotates the transport roller of the image forming apparatus, the intermittent stop cannot be performed when the transport roller is currently transporting the transfer sheet.

In such a case, until the timing when the motor M may be stopped (for example, when the motor M drives and rotates the transport roller shown in FIG. 2, after the transport roller stops transporting the transfer paper), The driving of the motor M is continued. Thereafter, the voltage instruction value to the motor M is set to 0, and the motor M is intermittently stopped until the temperature does not exceed the standard value. By doing so, it becomes possible to continue the operation near the limit without abnormally stopping the device using the motor M while satisfying the specification value of the winding temperature and the product specification. Downtime of the forming apparatus can be reduced.
When the motor M drives a member related to the transfer of transfer paper (also referred to as paper) in the image forming apparatus, the timing at which it can be stopped is determined by temporarily stopping the paper after the paper is carried out from the machine or inside the machine. This may be performed after the sheet is conveyed to a retreat position where the sheet can be removed.

FIG. 10 is a diagram similar to FIG. 7 for explaining the operation example.
In the case of the operation example described with reference to FIG. 7, when the moving average value Um of four sections of the torque average value, which is the average value of the torque instruction value for each section of the time ΔT, exceeds the threshold B, the voltage in the next section is always the voltage. The indicated value was set to 0 and the motor M was stopped intermittently.
If the control is performed in the same manner, the moving average value exceeds the threshold value B at Um + 1 in FIG. 10, so that the voltage indicated value is set to 0 and the motor M is intermittently stopped in the next shaded section.
However, since that section is the “stop prohibition timing”, the driving of the motor M is continued with a voltage command value corresponding to the torque command value input from the command value calculating unit 36 in FIG.

Thereafter, the voltage instruction value to the motor M is set to 0 in the section where the “stoppable timing” is reached. In the example of FIG. 10, the moving average value exceeds the threshold B three times (Um + 1, Um + 2, Um + 3) before the “stoppable timing” is reached. could not. Therefore, the voltage instruction value to the motor is set to 0 over the number of sections (three sections). Thereafter, the moving average value Um + 6 does not exceed the threshold value B, the voltage instruction value is returned to a normal value corresponding to the torque instruction value input from the instruction value calculation unit 36, and the motor M is driven.
As a result, the winding temperature of the motor M changes in a sawtooth waveform shown by a solid line in FIG. 10, and even when the moving average value exceeds the threshold value B, the driving temperature of the motor does not exceed the standard value and the specification. Can be continued. The dotted line curve shows a winding temperature rise curve when the torque average value maintains the threshold value B.

[Explanation of flowchart for realizing operation of FIG. 10]
FIG. 11 is a flowchart of a main routine of a process performed by the motor overload abnormality detecting section 40 in FIG. 3 for realizing the operation shown in FIG. 10, and FIG. 12 is a flowchart showing step S2 '(overload determination process) in FIG. It is a flowchart of a subroutine of ()).
The processing shown in this flowchart also includes a microcomputer (CPU) provided in the motor control unit 32 shown in FIG. 3 using the moving average value calculation unit 41, the determination unit 42, and the indicated value switching unit of the motor overload abnormality detection unit 40. This is a process performed by a program for functioning as a program 43.
In FIGS. 11 and 12, steps for performing the same determination or processing as in FIGS. 8 and 9 are denoted by the same step numbers, and descriptions thereof will be simplified or omitted.

When the CPU starts the processing of the flowchart shown in FIG. 11, and determines in step S1 that the motor is being started, it performs an overload determination processing shown in a subroutine of FIG. 12 in step S2 '.
The determination and processing in steps S201 to S208 are the same as those in the subroutine of FIG. In FIG. 9, if the CPU determines in step S208 that the current moving average value Um has exceeded the threshold value B, the CPU sets the intermittent stop flag in the next step S209.

However, in the case of FIG. 12, first, in step S221, the CPU counts up an intermittent stop cancellation number counter that counts the number Nc of sections in which intermittent stop is canceled, and increments Nc by +1. Initially, Nc is 0, so Nc = 1.
Thereafter, in step S222, the CPU determines whether it is the motor stoppable timing or not. If the motor stoppable timing is reached, the CPU proceeds to step S209 and sets the intermittent stop flag.
Then, in the next step S211, the count value Ta of the time measurement counter and the accumulated value Ua of the torque instruction value are cleared to 0, and the process returns to the main routine of FIG.

If the CPU determines in step S222 that it is not the motor stop enable timing (the motor stop prohibition timing), the process proceeds to step S223. Here, it is determined whether or not the count number Nc of the intermittent stop cancellation number counter has exceeded a preset maximum value Nmax (Nc> Nmax). As a result, if it is determined that Nc> Nmax, the motor forcible stop flag is set in step S224, and the process returns to the main routine of FIG.
When the CPU determines in step S223 that Nc> Nmax is not satisfied (Nc ≦ Nmax), in step S211, the count value Ta of the time measurement counter and the accumulated value Ua of the torque instruction value are cleared to 0, and the main routine of FIG. Return to routine.

When returning to the main routine, the CPU determines in step S9 whether the motor forced stop flag is set. As a result, if the motor forcible stop flag is set, the motor is forcibly stopped in step S10, the motor forcible stop is notified to the main control unit 30 in FIG. 3 (abnormal notification), and the processing of this flowchart is ended. .
When the main control unit 30 is notified of the motor forcible stop, the main control unit 30 displays characters or a mark of “motor forcible stop” on the operation panel, generates an alarm sound, and notifies the user of it. I can let you know.

  Even if it is the motor stop prohibition timing in the system, if the motor is not stopped, the situation that exceeds the temperature standard or the specification of the winding parts may occur. To do that. The maximum value Nmax of the count Nc (the number of sections for canceling the intermittent stop) of the intermittent stop cancel number counter used in step S223 of FIG. 12 is a count within a range where the winding temperature does not exceed W ° C. shown in FIG. The value is determined in advance by performing a temperature test.

If the CPU determines in step S9 that the motor forced stop flag has not been set, then it determines in step S3 whether the intermittent stop flag has been set. If it is set, the voltage indication value is set to 0 in step S4, the intermittent stop cancel number counter is counted down in step S11, and the count number Nc is set to Nc-1.
Thereafter, the CPU determines in step S12 whether or not Nc = 0. If Nc = 0, the CPU clears the intermittent stop flag in step S13. If not in step S12, the CPU returns to step S1 without change. The above-described processing is repeated.

If the CPU determines that the intermittent stop flag is not set in step S3, the CPU sets a value corresponding to the torque instruction value from the instruction value calculation unit 36 as the voltage instruction value to the motor in step S5. Then, the process returns to step S1 to repeat the above-described processing.
If the CPU determines in step S1 that the motor is not running, it clears the intermittent stop cancellation number counter (Nc = 0) in step S14, and then performs each of the clearing processes in steps S6 to S8 as in the case of FIG. After that, the process returns to step S1.
By doing so, the motor voltage indication value is set to 0 within the motor stoppable timing range for a time corresponding to the number of sections in which the count number Nc of the intermittent stop cancellation number counter is counted up in step S221 in FIG. Can be intermittently stopped.

  Also in this operation example, when the intermittent stop flag is set, the voltage indication value corresponding to the torque indication value input from the indication value calculation unit 36 in FIG. For example, a value reduced at a predetermined ratio such as 1/2 may be set. Alternatively, the output voltage instruction value may be switched by setting a fixed small value lower than the voltage instruction value corresponding to the input torque instruction value. In this case, the flag may be referred to as an "indicated value decreasing flag" rather than an "intermittent stop flag".

[Explanation of flowchart with added overload status notification function]
Next, an operation example in which a process for notifying the main control unit 30 of the overload state is added to each of the above-described operation examples will be described with reference to FIGS.
FIG. 13 is a flowchart of a main routine in which a process for notifying an overload state is added to the motor overload abnormality detection operation shown in FIG. 8, and is shaded after step S4 in FIG. Only steps S15 and S16 are added.

In this operation example, when the intermittent stop flag is set in step S3 and the CPU sets the voltage instruction value to 0 in step S4, in the next step S15, it is determined whether or not the first intermittent operation after the motor is started. to decide. As a result, if it is determined that the operation is the first intermittent operation after the motor is started, the overload state is notified to the main control unit 30 in FIG. 3 (abnormal notification) in step S16, and the process returns to step S1.
Thus, the main control unit 30 can display characters or marks such as “overload state” or “motor intermittent operation” on the operation panel, generate a warning sound, and notify the user of it. it can.
When the CPU determines in step S15 that the operation is not the first intermittent operation after the motor is started, the process returns to step S1.

  FIG. 14 is a flowchart of a main routine in which a process for notifying an overload state has been added to the motor overload abnormality detection operation shown in FIG. 11, and hatching is performed between step S4 and step S11 in FIG. Only the steps S15 and S16 shown are added. The determination in step S15 and the processing in step S16 are the same as steps S15 and S16 in FIG. 13 described above.

  When the overload state is detected, it is considered that maintenance of the system equipped with the motor (the image forming apparatus in this embodiment) is required. Therefore, when an overload condition is detected and the motor starts intermittent operation, the user is notified of it and the user or service person can perform repair while the motor is still performing intermittent operation. Preparations can be made. Thereby, downtime can be further reduced.

[Operation of the motor overload abnormality detection unit in FIG. 4]
The operation of the motor overload abnormality detection unit 40 'in the motor drive control device of the other embodiment shown in FIG. 4 is also performed by the motor overload abnormality detection unit 40 in the motor drive control device of the embodiment shown in FIG. Operation is almost the same.
The difference from the operation of the above-described embodiment is that, as described in the description of FIG. 4, the motor driving current detecting means 38 for detecting the driving current of the motor M is provided, and the detected value of the motor driving current is transmitted to the motor. This is the point of input to the load abnormality detection unit 40 '.

The moving average value calculating section 41 'of the motor overload abnormality detecting section 40' A / D converts the motor driving current value detected by the motor driving current detecting means 38 and continuously captures the value in a short cycle. An average value for each section (predetermined time) is calculated and stored. Then, a moving average value of the motor drive current value in a preset number of sections up to the latest section is calculated.
The determination unit 42 'determines whether there is an overload abnormality by comparing the moving average value of the motor drive current calculated by the moving average value calculation unit 41' with a preset threshold value.

  When the determination unit 42 ′ determines that there is no overload abnormality, the instruction value switching unit 43 outputs the voltage instruction value corresponding to the torque instruction value input from the instruction value calculation unit 36 as it is. When the determination unit 42 'determines that there is an overload abnormality, the instruction value switching unit 43 switches the voltage instruction value to, for example, zero (0) or a value significantly lower than the voltage instruction value corresponding to the input torque instruction value. Output.

  Therefore, when describing the operation of this embodiment, the “torque instruction value (voltage instruction value)” in FIG. 5 is set as the “motor drive current value”, and the “torque average value (voltage)” in FIGS. 6, 7 and 10 is used. Average value) is referred to as “motor drive current average value”. Therefore, ΔU in FIGS. 7 and 10 is the “motor drive current average value” for each section, and Um is the motor drive current average value for a predetermined number of sections up to and including the latest section (four sections in the embodiment). It is a moving average value.

The flowchart of a program for causing the microcomputer (CPU) of the motor control unit 32 in FIG. 4 to function as each unit of the motor overload abnormality detection unit 40 'is also shown in each of the flowcharts of FIGS. 8 and 9 or FIGS. Is the same as Further, each flowchart of FIG. 13 may be replaced with FIG. 13 and each flowchart of FIG. 14 may be replaced with FIG.
However, in these figures, ΔU and Um are as described above. Ua in step S202 in FIGS. 9 and 12 is a cumulative addition value of the motor drive current values in the section of time ΔT, and “current torque instruction value” is “current motor drive current value”. Further, the threshold value B to be compared with the current moving average value of the motor drive current in step S208 is a threshold value of the average value and the moving average value of the motor drive current, and within the time ΔT shown in FIGS. The temperature is set in a range that does not reach Z ° C to W ° C.

[Motor overload abnormality detection method]
A motor overload abnormality detection method according to the present invention detects a motor overload abnormality based on a motor drive instruction value or an actual motor drive current value calculated according to the rotation speed of the motor, and responds to the detection result. This is a method of outputting a motor drive instruction value.
The embodiment has a moving average value calculation procedure, a determination procedure, and an instruction value switching procedure executed by each unit of the above-described motor overload abnormality detection unit 40 or 40 '. Each procedure is executed by the microcomputer (CPU) of the motor control unit 31 as described in each flowchart described above.
When detecting an overload abnormality of the motor based on the motor drive current value, the operation procedure by each unit of the motor overload abnormality detection unit 40 'in the motor drive control device shown in FIG. Partially modified as described above.

[Supplemental explanation]
The embodiment of the present invention has been described above, but the specific configuration of each unit and the content of processing in the embodiment are not limited to those described therein.
Further, it is needless to say that the present invention is not limited to the above-described embodiment, and is not limited at all except having the technical features described in each claim of the claims.
Furthermore, the configuration examples, operation examples, modification examples, and the like of the embodiment described above may be appropriately changed, added, or partially deleted, and may be implemented in any combination as long as they do not conflict with each other. is there.

1: Image forming unit 2: Paper feeding unit 3: Image reading unit (scanner unit)
4: automatic document feeder (ADF) 5: paper discharge tray 6: manual feed tray 10: image forming unit 11: photosensitive drum 12: charging roller 13: developing unit
14: Image writing unit 15: Intermediate transfer belt 16: Positioning roller pair
17: Secondary transfer roller 18: Conveying belt 19: Fixing device 20: Paper feed cassette 21: Paper feed / transport mechanism 22: Motor 23: Small gear
24: spur gear 25: transport roller 26: driven roller
30: Main control unit 31: Motor drive control unit 32: Motor control unit 33: Motor drive circuit 35: Encoder (speed detection unit) 36: Instruction value calculation unit 37: PWM conversion unit 38: Motor drive current detection unit 40, 40 ': Motor overload abnormality detecting units 41, 41': moving average value calculating units 42, 42 ': determining unit 43: indicated value switching unit M: motor P: transfer paper (recording medium)

JP-A-2015-33298

Claims (12)

A motor overload abnormality detection device that detects an overload abnormality of a motor based on a motor drive instruction value calculated according to a rotation speed of the motor, and outputs a motor drive instruction value according to the detection result,
A moving average value for acquiring a motor drive instruction value calculated in accordance with the rotation speed of the motor for each section of a fixed time, and calculating a moving average value of the motor drive instruction value for a predetermined number of sections including the latest section. Calculating means;
Comparing the moving average value calculated by the moving average value calculation means with a preset threshold value, and determining means for determining the presence or absence of an overload abnormality;
If the determining means determines that there is no overload abnormality, a motor driving instruction value corresponding to the motor driving instruction value calculated according to the rotation speed of the motor is output, and the determining means determines that there is an overload abnormality. the case, possess the indicated value switching means for switching the motor driving instruction value output to zero or the computed value lower than the motor driving instruction value,
The instruction value switching means, when the determination means determines that there is an overload abnormality, and when it is not the motor stoppable timing, a motor drive instruction value calculated according to the rotation speed of the motor. Outputs the drive instruction value, counts the number of sections in which the state continues, and sets the motor drive instruction value to be output to zero or the calculated motor only for the counted number of sections after the motor stoppable timing. A motor overload abnormality detection device characterized by switching to a value lower than a drive instruction value . The moving average value calculating means calculates and obtains a motor drive instruction value calculated in accordance with the rotation speed of the motor for each section of a predetermined time, and obtains the motor drive instruction value for a predetermined number of sections including the latest section. The motor overload abnormality detecting device according to claim 1, wherein a moving average value of the average value of the motor drive instruction value is calculated. The motor overload abnormality detection device according to claim 1 or 2,
  When the determination unit determines that there is an overload abnormality, a unit for forcibly stopping the motor is provided if the number of sections not at the motor stoppable timing exceeds a preset number of sections. Motor overload abnormality detection device. A motor overload abnormality detection device that detects an overload abnormality of a motor based on a motor drive current value and outputs a motor drive instruction value according to the detection result,
A moving average value calculating unit that obtains the motor drive current value for each section of a fixed time, and calculates a moving average value of the motor drive current value for a predetermined number of sections including the latest section;
Comparing the moving average value calculated by the moving average value calculation means with a preset threshold value, and determining means for determining the presence or absence of an overload abnormality;
If the determining means determines that there is no overload abnormality, a motor drive instruction value corresponding to the motor drive instruction value calculated according to the rotation speed of the motor is output, and the determining means determines that there is an overload abnormality. If, possess the indicated value switching means for switching the motor driving instruction value output to zero or the computed value lower than the motor driving instruction value,
The instruction value switching means, when the determination means determines that there is an overload abnormality, and when it is not the motor stoppable timing, a motor drive instruction value calculated according to the rotation speed of the motor. Outputs the drive instruction value, counts the number of sections in which the state continues, and sets the motor drive instruction value to be output to zero or the calculated motor only for the counted number of sections after the motor stoppable timing. A motor overload abnormality detection device characterized by switching to a value lower than a drive instruction value . The moving average value calculating means calculates and acquires the average value of the motor drive current value for each section of a predetermined time, and moves the average value of the motor drive current value for a predetermined number of sections including the latest section. The motor overload abnormality detecting device according to claim 4 , wherein an average value is calculated. The motor overload abnormality detection device according to claim 4 or 5 ,
When the determination unit determines that there is an overload abnormality, a unit for forcibly stopping the motor is provided if the number of sections not at the motor stoppable timing exceeds a preset number of sections. Motor overload abnormality detection device. The motor overload abnormality detection device according to any one of claims 1 to 6,
When the instruction value switching means switches the output motor drive instruction value to zero or a value lower than the calculated motor drive instruction value for the first time, there is provided means for notifying that an overload state has occurred. Motor overload abnormality detection device. Speed detection means for detecting the rotation speed of the motor,
A motor control unit that performs drive control of the motor,
A motor drive circuit that drives the motor under the control of the motor control unit,
The motor control unit,
An instruction value calculation unit that calculates a motor drive instruction value based on the rotation speed of the motor detected by the speed detection unit;
A motor overload abnormality detection device according to any one of claims 1 to 3 ,
Means for controlling the motor drive circuit in accordance with a motor drive instruction value output from the instruction value switching means of the motor overload abnormality detection device. Speed detection means for detecting the rotation speed of the motor,
A motor control unit that performs drive control of the motor,
A motor drive circuit that drives the motor under the control of the motor control unit;
Motor drive current detection means for detecting the drive current of the motor,
The motor control unit,
An instruction value calculation unit that calculates a motor drive instruction value based on the rotation speed of the motor detected by the speed detection unit;
A motor overload abnormality detection device according to any one of claims 4 to 6 ,
Means for controlling the motor drive circuit in accordance with a motor drive instruction value output from the instruction value switching means of the motor overload abnormality detection device.   An image forming apparatus comprising: the motor drive control device according to claim 8 or 9; and a motor whose drive is controlled by the motor drive control device. A motor overload abnormality detection method for detecting a motor overload abnormality based on a motor drive instruction value calculated according to a motor rotation speed and outputting a motor drive instruction value according to the detection result,
A moving average value for acquiring a motor drive instruction value calculated in accordance with the rotation speed of the motor for each section of a fixed time, and calculating a moving average value of the motor drive instruction value for a predetermined number of sections including the latest section. Calculation procedure,
By comparing a predetermined threshold value and the moving average value calculated in the moving average value calculating procedure, a determination procedure whether the abnormal overload,
If it is determined in the determination procedure that there is no overload abnormality, a motor drive instruction value corresponding to the motor drive instruction value calculated according to the rotation speed of the motor is output, and it is determined that there is an overload abnormality in the determination procedure. the case, possess the indicated value switching procedure for switching the motor driving instruction value output to zero or the computed value lower than the motor driving instruction value,
In the instruction value switching procedure, when it is determined that there is an overload abnormality in the determination procedure, and when it is not the motor stoppable timing, a motor driving instruction value calculated according to the rotation speed of the motor is used. Outputs the drive instruction value, counts the number of sections in which the state continues, and sets the motor drive instruction value to be output to zero or the calculated motor only for the counted number of sections after the motor stoppable timing. A method for detecting a motor overload abnormality, characterized by switching to a value lower than a drive instruction value . A motor overload abnormality detection method for detecting a motor overload abnormality based on a motor drive current value and outputting a motor drive instruction value according to the detection result,
A moving average value calculating step of obtaining the motor drive current value for each section of a fixed time, and calculating a moving average value of the motor drive current value for a predetermined number of sections including the latest section;
A comparing step of comparing the moving average value calculated in the moving average value calculation procedure with a preset threshold value, and determining a presence or absence of an overload abnormality;
When it is determined that there is no overload abnormality in the determination procedure, a motor drive instruction value corresponding to the motor drive instruction value calculated according to the rotation speed of the motor is output, and it is determined that there is an overload abnormality in the determination procedure. If, possess the indicated value switching procedure for switching the motor driving instruction value output to zero or the computed value lower than the motor driving instruction value,
In the instruction value switching procedure, when it is determined that there is an overload abnormality in the determination procedure, and when it is not the motor stoppable timing, a motor driving instruction value calculated according to the rotation speed of the motor is used. Outputs the drive instruction value, counts the number of sections in which the state continues, and sets the motor drive instruction value to be output to zero or the calculated motor only for the counted number of sections after the motor stoppable timing. A method for detecting a motor overload abnormality, characterized by switching to a value lower than a drive instruction value .