JP4985281B2 - Motor abnormality detection device and image forming apparatus having the same - Google Patents

Description

  The present invention relates to a motor abnormality detection device that detects a motor abnormality and an image forming apparatus including the motor abnormality detection device.

  OA devices such as printers, multifunction devices, and copiers, and electrical products such as household appliances such as washing machines and vacuum cleaners use the driving force of the motor to operate the parts. When the motor stops, the electrical product cannot perform the predetermined function, and in the worst case, it may cause a failure. For this reason, conventionally, a motor rotation state is sensed to detect a motor abnormality.

  For example, in Patent Document 1, a resistor is connected to each of three sensor circuits that detect the position of a rotor constituting a motor. These three resistors have different resistance values and are generated by a combination of a high voltage or a low voltage output from the three sensor circuits, respectively, and the parallel resistance value of any two resistors and the resistance of another resistor. The value is made different. The three resistors are connected via a connection point A to a power source side resistor connected to the power source. The connection point A is connected to the input unit of the microcomputer.

  In such a motor abnormality detection device described in Patent Document 1, the voltage applied to the connection point A is a power supply side resistor and any one of the three resistors or two resistors. The voltage is divided. As described above, since the resistance values of the three resistors are different from each other, the voltage applied to the connection point A differs depending on the combination of the high voltage or the low voltage that the sensor circuit detects and outputs the rotation of the rotor.

  Therefore, even if three sensor circuits are connected to one input unit, the motor abnormality detection device described in Patent Document 1 depends on the magnitude of the voltage applied to the connection point A, and any sensor circuit is a rotor. The rotation position of the rotor can be detected by determining whether the rotation of the rotor has been detected.

JP 2003-154188 A

  However, the conventional motor abnormality detection device has the magnitude of the voltage applied to the connection point A connecting the resistor connected to each of the three sensor circuits for detecting the rotation of the rotor of the motor and the power supply resistor. Based on this, the rotational position of the rotor is detected. In the three sensor circuits, for example, when noise is generated due to the influence of magnetism generated by a motor or the like, the sum of noise generated by each sensor circuit affects the voltage output from the connection point A, resulting in poor detection accuracy. Sometimes it became stable.

  In addition, since the conventional motor abnormality detection device is provided with one input unit for one motor, it is necessary to prepare as many input units as the number of motors in order to detect the rotation state of a plurality of motors. . In recent years, higher functionality and higher speed of products have progressed, and the number of motors has increased, and the number of sensors that detect the rotation of the motor has also increased in proportion thereto. On the other hand, the price and size of hard wafers have been reduced, and the number of control CPUs and ASIC input units is limited. As described above, many restrictions on hardware are imposed on the detection of the rotation of the motor, and there is a strong demand to reduce the number of input units and downsize the control unit.

  The present invention has been made to solve the above-described problems, and an object thereof is to provide a motor abnormality detection device capable of stabilizing detection accuracy while reducing the number of input units, and an image forming apparatus including the motor abnormality detection device. To do.

A motor abnormality detection apparatus and an image forming apparatus including the same according to the present invention have the following configurations.
(1) In a motor abnormality detection device that detects rotation abnormality of a plurality of motors, a plurality of rotating bodies that are arranged corresponding to the plurality of motors, are rotationally driven by the corresponding motors, and each have a through hole portion; A plurality of sensor means arranged corresponding to the plurality of rotating bodies and outputting detection signals that change depending on the through-hole portions; and rotations of the plurality of motors based on detection signals from the plurality of sensor means. Rotation detecting means for detecting a state, and when the plurality of motors normally rotate, the through holes are provided so that the change states of the detection signals output from the plurality of sensor means are different from each other. The plurality of sensor means are OR-connected to the input part of the rotation detecting means.

(2) In the invention described in (1), the rotation detection unit includes a separation unit that separates the detection signal input to the input unit.

(3) In the invention described in (1) or (2), the rotating body is constituted by a gear connected to the motor.

(4) In the invention according to any one of (1) to (3), the recording paper supplied with the developer is conveyed between a heating roller and a pressing roller, and the developer is transferred to the recording paper. One of the motors is for driving the heating roller, and the through hole portion of the rotating body corresponding to the motor includes: The change time of the detection signal output from the sensor means arranged corresponding to the rotating body is set to be shorter than the change time of the detection signal output from the other sensor means.

(5) In the invention according to any one of (1) to (4), the plurality of sensor means are wired or connected to the input unit.

(6) An image forming apparatus comprising the invention described in any one of (1) to (5).

  In the motor abnormality detection device and the image forming apparatus of the present invention having the above-described configuration, the plurality of sensor units output detection signals that change depending on the through-hole portion of the rotating body that is rotationally driven by the motor. Since the plurality of sensor means are OR-connected to the input part of the rotation detection means, the detection signals output from the plurality of sensor means are collectively input to the input part of the rotation detection means, but are output from each sensor. Therefore, the rotation state of the motor can be detected based on the detection signal input to the input unit. Therefore, even if the number of motors increases, the number of input units of the rotation detection means does not increase, and the control unit can be downsized. Therefore, according to the motor abnormality detection device and the image forming apparatus of the present invention, the detection accuracy can be stabilized while reducing the number of input units.

  In addition, since the motor abnormality detection device of the present invention separates the detection signal input to the input unit, even if the sum of a plurality of detection signals is input to the input unit, it is separated to rotate the plurality of motors. The state can be detected individually.

  Moreover, since the motor abnormality detection apparatus of this invention is comprised with the gear which a rotary body connects with a motor, the mechanism which detects rotation of a motor can be provided cheaply and compactly.

  Further, when the motor abnormality detection device of the present invention is used in an image forming apparatus, the change time of the detection signal output by the sensor means detecting and outputting the through-hole portion of the gear corresponding to the motor that drives the heating roller, Since the change time of the detection signal output from the other sensor means is shorter, the abnormality of the motor that drives the heating roller can be quickly detected before the heating roller sticks to the pressing roller.

  Further, in the motor abnormality detection device of the present invention, the plurality of sensor means are wired or connected to the input unit, so that the number of elements used in the circuit can be suppressed.

  Next, an embodiment of a motor abnormality detection device and an image forming apparatus including the same according to the present invention will be described with reference to the drawings.

<Overall configuration of image forming apparatus>
FIG. 1 is a diagram illustrating an internal configuration of a printer 1 that is an example of an “image forming apparatus” according to an embodiment of the present invention.
The printer 1 is detachably mounted with a paper feed cassette 4 that accommodates the recording paper 3 from the front side of the casing 2. The casing 2 rotatably connects the cover 2B to the main body 2A so as to close the opening that opens above the main body 2A. A paper discharge tray 5 is provided on the upper surface of the cover 2B.

  Inside the casing 2, a conveyor belt 8 wound around a conveyor belt driving roller 6 and a driven roller 7 is rotatably arranged at the center, and is sequentially supplied from the upstream side to the downstream side of the conveyor belt 8. A paper unit 11, an image forming unit 12, and a paper discharge unit 13 are arranged.

  When the pickup roller 14 picks up one recording sheet 3 from the sheet feeding cassette 4, the sheet feeding unit 11 conveys the recording sheet 3 to the registration rollers 17 by the conveying rollers 15 and 16. The registration roller 17 corrects the inclination of the recording paper 3 and then sends the recording paper 3 to the image forming unit 12.

  The image forming unit 12 includes a first image forming unit 20Y, a second image forming unit 20M, and a third image forming unit 20C that store toners of yellow (Y), magenta (M), cyan (C), and black (K). The fourth image forming units 20 </ b> K are arranged horizontally side by side from the upstream side to the downstream side of the transport belt 8. A fixing device 27 is arranged on the downstream side of the fourth image forming unit 20K arranged on the most downstream side.

  The first to fourth image forming units 20Y, 20M, 20C, and 20K have the same configuration. The subscripts “Y”, “M”, “C”, “K” of the first to fourth image forming units 20Y, 20M, 20C, 20K are the first to fourth image forming units 20Y, 20M, 20C, 20K. If there is no need to distinguish between them, the subscripts are omitted as appropriate in the following description. In FIG. 1, it is difficult to see the drawing if all the components of the first to fourth image forming units 20 </ b> Y, 20 </ b> M, 20 </ b> C, and 20 </ b> K are described, it is difficult to see the drawings. The code is described.

  In the image forming unit 20, after the charger 23 discharges the surface of the photoconductor 22 that has been neutralized by the static eliminator 21 to make the photoconductor 22 durable, the exposure unit 24 irradiates the surface of the photoconductor 22 with laser light. An electrostatic latent image is formed, and then toner is supplied from the developing cartridge 25 to the surface of the photosensitive member 22 to visualize the electrostatic latent image, thereby forming a toner image. The photoconductor 22 transfers the toner image formed on the surface thereof to the recording paper 3 between the photoconductor 22 and the transfer roller 26 disposed so as to face the conveyance belt 8. Thereafter, the photoreceptor 22 is neutralized by the static elimination 21.

  The fixing device 27 includes a heating roller 28 that is heated by a halogen heater, and a pressure roller 29 that is disposed so as to be in pressure contact with the heating roller 28. When the recording paper 3 on which the toner image is formed is conveyed between the heating roller 28 and the pressure roller 29, the fixing device 27 melts the toner by the heat of the heating roller 28 and applies the toner to the recording paper 3. Then, the recording paper 3 is sent out to the paper discharge unit 13.

  The paper discharge unit 13 includes a paper discharge roller 30. The paper discharge roller 30 discharges the recording paper 3 from the discharge port 9 of the casing 2 to the paper discharge tray 5.

  Meanwhile, the printer 1 includes first to fourth image forming units 20Y, 20M, 20C, and 20K, and can select and execute monochrome printing and color printing. When performing monochrome printing, the first to third image forming units 20Y, 20M, and 20C are not used.

  Therefore, during color printing, the printer 1 uses the developing cartridges 25Y, 25M, and 25C of the first to third image forming units 20Y, 20M, and 20C in the same manner as the fourth image forming unit 20K as shown in FIG. The toner cartridges 25Y, 25M, and 25C of the first to third image forming units 20K, 18M, and 18C are arranged at a printing position for supplying toner to the third photosensitive members 22Y, 22M, and 22C, and at the time of monochrome printing. 1 is arranged so as to be moved upward from the printing position shown in FIG. 1 and disposed at a retracted position separated from the first to third photoconductors 22Y, 22M, and 22C.

  In the printer 1, a series of printing operations is controlled by the control unit 10. In such a printer 1, the rotational state of a motor 40 (see FIG. 2) that generates a driving force applied to components (the arrangement switching device 18 and various rollers 14, 15, 16, 28, etc.) that operate the printer 1 is monitored. In addition, a motor abnormality detection device 19 that detects abnormality of the motor 40 is mounted.

<Configuration of motor abnormality detection device>
FIG. 2 is a schematic configuration diagram of the motor abnormality detection device 19 shown in FIG. Here, the subscripts “A”, “B”, and “C” are for distinguishing a plurality of sensor boards 33, drivers 39, motors 40, gears 41, sensors 42, and the like. In the following description, subscripts are omitted as appropriate unless there is a need for distinction.

  The motor abnormality detection device 19 includes a control unit 10 that is an example of “rotation detection means”, a plurality of motors 40, a plurality of gears 41 that are examples of “rotating bodies”, and a plurality of examples that are examples of “sensor means”. Sensor 42.

  The control unit 10 incorporates a controller board 31 and an engine board 32. The controller board 31 is equipped with a well-known CPU 34, ROM 35, and RAM 36, and processes and calculates various data. The ROM 35 stores a motor abnormality detection program 37 (described later) for detecting a motor abnormality.

  The engine board 32 includes an ASIC 38 and a plurality of drivers 39. Each driver 39 is connected to a motor 40 that generates a driving force applied to the component. The engine board 32 individually controls the operation of each motor 40 as will be described later. The engine board 32 has a plurality of sensor boards 33 connected to the ASIC 38 and inputs the detection result of the sensor 42.

  Here, the printer 1 is equipped with a large number of motors, and the motor abnormality detection device 19 can detect the abnormality of each motor 40. However, the motor abnormality detection method is the same regardless of the number of motors 40.

  Therefore, in this embodiment, in order to make the explanation easy to understand, a first motor 40A that generates a driving force applied to the arrangement switching device 18 and a second motor 40B that generates a driving force for rotating the transport belt driving roller 6 are provided. The motor abnormality detection device 19 will be described by taking the third motor 40C that generates a driving force for rotating the heating roller 28 as an example. FIG. 2 shows the first to third motors 40A, 40B, and 40C and their accompanying parts (first to third gears 47A, 47B, 47C, first to third gears 41A, 41B, 41C, and first Only the third sensors 42A, 423B, 42C) will be described.

  Gears 47 are arranged in one-to-one correspondence with the motor 40. A gear 41 is engaged with the gear 47 and is driven to rotate by a corresponding motor 40. In other words, the rotation of the gear 41 and the rotation of the motor 40 are synchronized. A sensor 42 is disposed corresponding to the gear 41. The sensor 42 is attached to the sensor substrate 33 and detects the rotation of the gear 41. The output of each sensor 42 is wired or connected to the ASIC 38 of the engine board 32.

  The sensor 42 includes a light emitting diode D and a phototransistor TR. The anode side of the light emitting diode D is connected to the first contact Q1 through the resistor R1. The first contact Q1 is connected to a sensor board power source. The cathode side of the light emitting diode D is connected to a connection point P1 between the second contact Q2 and the phototransistor TR. The second contact Q2 is connected to the ground. The phototransistor TR is disposed on the sensor substrate 33 so that the base receives light from the light emitting diode D and is applied with a voltage. The phototransistor TR has an emitter connected to the second contact Q2, and a collector connected to the input part 38a of the ASIC 38 via the output line L.

  Such a phototransistor TR is in a high impedance state while the base does not receive light from the light emitting diode D. However, when the base receives light from the light emitting diode D, the phototransistor TR changes from a high impedance state to a low state (hereinafter, “ L ”) and output as an open collector.

  The phototransistors TRA, TRB, TRC of the first to third sensor substrates 33A, 33B, 33C are connected to the output line L in parallel. In the output line L, a fourth connection point P4 is provided between the phototransistors TRA, TRB, TRC and the ASIC 38, and a pull-up resistor R2 is connected to the fourth connection point P4. The pull-up resistor R2 is connected to the pull-up power supply via the third contact Q3, and causes the ASIC 38 to output a high state (hereinafter referred to as “H”) when the phototransistors TRA, TRB, TRC are in a high impedance state.

  Accordingly, when any of the phototransistors TRA, TRB, and TRC is switched from the high impedance state to “L”, “L” is input to the input unit 38 a of the ASIC 38. In other words, the collectors of the phototransistors TRA, TRB, and TRC are connected to the input unit 38a by wire ORing each open collector output to one common pull-up resistor R2.

<Relationship between gear and sensor>
Next, the relationship between the gear 41 and the sensor 42 will be described. FIG. 3 is an external perspective view showing an example of the third gear 41 </ b> C shown in FIG. 2 and a third sensor 42 arranged on the third gear 41.
As shown in FIG. 3, the third gear 41 </ b> C is connected to an end portion of the heating roller 28, for example. In the third gear 41C, gear teeth (not shown) formed on the outer peripheral surface mesh with a reduction gear train (not shown) connected to the third motor 40C. When the third motor 40C rotates, the third gear 41C rotates in the direction of the arrow in the figure, and transmits the driving force of the third motor 40C to the heating roller 28. The third gear 41C is made of a resin having heat resistance and strength.

  The third gear 41C has a shielding plate 43C protruding from the end surface opposite to the end surface to which the heating roller 28 is attached. The shielding plate 43C is formed in a cylindrical shape around the axis of the third gear 41C. The shielding plate 43C has a plurality of through-hole portions 44C provided at equal intervals in the circumferential direction. Each through hole 44C is cut out long from the end of the shielding plate 43C along the axial direction of the third gear 41C, and is formed in a slit shape.

  The third sensor 42C is installed so that the light emitting unit 45 and the light receiving unit 46 are disposed to face each other with the shielding plate 43C interposed therebetween. The light receiving unit 45 incorporates the above-described light emitting diode DC (see FIG. 2). Further, the light receiving unit 46 is configured by the above-described phototransistor TRC (see FIG. 2).

FIG. 4 is a schematic configuration diagram of the first gear 41A shown in FIG. FIG. 5 is a schematic configuration diagram of the second gear 41B shown in FIG.
The first gear 41A shown in FIG. 4 and the second gear 41B shown in FIG. 5 have the same configuration as the third gear 41C shown in FIG. 3 except for the shape and number of the through holes 44A and 44B.

  The number of the through-hole portions 44 is formed in the gear 41 as much as it is necessary to detect the rotation of the motor 40 more severely.

  Specifically, when the rotation of the third motor 40C is stopped in a state where the recording paper 3 is not conveyed between the heating roller 28 and the pressing roller 29, the heating roller 28 concentrates and heats the pressing roller 29 at one point. , May stick to the pressing roller 29. In this case, the printer 1 may not be used as a product. Therefore, it is desirable for the third motor 40C to detect the rotation abnormality as soon as possible, and it is necessary to monitor the rotation state severely.

  On the other hand, when the first and second motors 40A and 40B stop rotating, printing cannot be resumed, but there is no risk of failure or the like. Therefore, it is not necessary to monitor the rotation of the first and second motors 40A and 40B as severely as the third motor 40C.

  Therefore, in the present embodiment, only one through hole 44A is formed in the first gear 41A connected to the first motor 40A (see FIG. 4), and the second gear 41B connected to the second motor 40B is formed in the through hole. Two 44Bs are formed (see FIG. 5), and six through holes 44C are formed in the third gear 41C connected to the third motor 40C (see FIG. 3).

  When a plurality of through holes 44 are formed in the gear 41, it is desirable that the even number of through holes 44 be positioned symmetrically with the shielding plate 43.

  On the other hand, the shape of the through-hole portion 44 (the width dimension in the circumferential direction of the shielding plate 43 (hereinafter referred to as “width dimension”)) is the change state of the detection signal output from the sensor 42 (in particular, the period of “L”). (Detection time)) is determined to be different from the change state of detection signals output from the other sensors 42 (particularly, the “L” period (detection time)). This is because the rotation state of the first to third motors 40A, 40B, and 40C can be determined from the detection signal input to the input unit 38a.

  The change state of the detection signal (the period (detection time) of “L” is determined according to the rotational speed of the gear 41 and the width dimension and number of the through holes 44. Accordingly, the width dimension of the through holes 44 is determined by the gear. Based on the rotational speed of 41 and the number of through-hole portions 44, it is determined so as not to overlap with the change state (“L” period (detection time)) of the detection signals of the other sensors 42.

  In the present embodiment, the rotation speeds of the first to third gears 41A, 41B, and 41C are made the same so that the relationship between the through hole portion 44 and the output of the sensor 42 can be easily understood. In the first to third gears 41A, 41B, 41C, the width dimension of the through hole 44 is set larger in the order of the through holes 44A, 44B, 44C.

<Internal configuration of ACIC>
FIG. 6 is a logic diagram showing an internal configuration of the ASIC 38 shown in FIG.
The ASIC 38 includes a CPU input / output interface (hereinafter referred to as “CPU I / F”) 51 that controls input / output of data to / from the CPU 34. The CPU I / F 51 is connected to first to third motor control circuits 52A, 52B, and 52C.

  The CPU I / F 51 is connected to a noise cancel setting register 53 that stores a noise cancel setting value. The “noise cancel setting value” indicates the period of the waveform that is determined to be noise, and is set by software or the like. The “noise cancel setting value” is set to a period smaller than the period of the detection signal (L) output from each sensor 42 so that the filter circuit 54 does not remove the normal sensor waveform of the sensor 42. In this embodiment, the noise cancellation setting value is “5”. A filter circuit 54 for removing noise is connected to the noise cancellation setting register 53.

  The CPU I / F 51 is connected to a reference clock setting register 55 that stores a reference clock. The “reference clock” refers to a clock signal that serves as a reference when the pulse width measurement circuit 56 measures the pulse width by the number of pulses. Connected to the reference clock setting register 55 is a pulse width measurement circuit 56 that measures the pulse width PW of the “L” of the sensor output waveform based on the “reference clock”.

  The CPU I / F 51 is connected to first to third pulse width setting registers 57A, 57B, and 57C that store pulse width determination values. The first to third pulse width setting registers 57A, 57B, and 57C include first to third comparators 59A, 59B, and 59C that constitute the comparison circuit 58. The first to third comparators 59A, 59B, 59C are provided in a number corresponding to the number of sensors 42. The first to third pulse width setting registers 57A, 57B, and 57C are provided one-on-one with the first to third comparators 59A, 59B, and 59C.

  Here, the “pulse width determination value” refers to a threshold when the first to third comparators 59A, 59B, 59C determine the magnitude of the pulse width. The “pulse width determination value” is desirably the pulse width of the detection signal (L) output when the sensor 42 normally detects the through hole 44 (may be a pulse width including an error). The “pulse width judgment value” is set by software or the like.

FIG. 7 is a diagram showing an example of pulse width determination values set by the first to third pulse width setting registers 67A, 67B, and 67C shown in FIG.
In the present embodiment, the pulse width determination value of the first pulse width setting register 57A is set to “50”. Further, the pulse width determination value of the second pulse width setting register 57B is set to “25”. Further, the pulse width determination value of the third pulse width setting register 57C is set to “10”.

  As shown in FIG. 6, a pulse discrimination circuit 60 is connected to the comparison circuit 58. The pulse discrimination circuit 60 is connected to first to third sensor input registers 61A, 61B, and 61C that can read and write data. The pulse discriminating circuit 60 uses the first to third sensor input registers 61A, 61B based on the comparison results D (2), (1), (0) input from the first to third comparators 59A, 59B, 59C. , 61C, the set value “1” is written. The first to third sensor input registers 61A, 61B, 61C are connected to the CPU I / F 51, and the CPU 34 reads and writes data.

<Description of Operation: Overall Operation of Printer 1>
First, the overall operation of the printer 1 will be described.
For example, when the CPU 34 receives a print command from a personal computer (not shown), the CPU 34 stores the print data in the RAM 36. The CPU 34 generates an operation control command based on the print command and outputs it to the ASIC 38.

The ASIC 38 generates an operation execution command to be output to the driver 39 based on the operation control command, and outputs the operation execution command to each driver 39. Each driver 39 rotates the motor 40 at a predetermined rotation speed in accordance with the operation execution command.
At this time, the CPU 34 also gives operation commands to the paper feed unit 11, the image forming unit 12, and the paper discharge unit 13, and prints print data on the recording paper 3.

  That is, when the print command instructs color printing, the arrangement switching device 18 arranges the first to third developing units 25Y, 25M, and 25C at the printing position by the driving force of the first motor 40A, and in that state. The conveying belt driving roller 6 and the heating roller 28 are rotated by the driving force of the second and third motors 40B, 40C, etc., and color printing is performed on the recording paper 3.

  On the other hand, when the print command instructs monochrome printing, the arrangement switching device 18 arranges the first to third developing units 25Y, 25M, and 25C at the retracted position by the driving force of the first motor 40A, and in that state. The conveying belt driving roller 6 and the heating roller 28 are rotated by the driving force of the second and third motors 40B and 40C to perform monochrome printing on the recording paper 3.

<Motor rotation detection method>
The motor abnormality detection device 19 detects the rotation state of the motor 40 while the motor 40 rotates. A method for detecting the rotation of the motor will be described with reference to FIGS. 8 shows sensor waveforms output from the first to third sensors 42A, 42B, and 42C shown in FIG. 2, a sensor input waveform input by the filter circuit 54 shown in FIG. 6, and a sensor output waveform output by the filter circuit 54. FIG. 6 is a diagram illustrating a waveform of a reference clock signal output from the noise cancellation setting register 53 to the filter circuit 54. FIG. 9 is a diagram illustrating sensor input pulse measurement data output from the pulse width measurement circuit illustrated in FIG. 6 and sensor input comparison data output from the comparison circuit. FIG. 10 is a diagram showing determination by the pulse determination circuit 60 shown in FIG.

  At the same time as the motor 40 is driven, the sensor 42 emits light when the light-emitting diode D is supplied with a current from the sensor power supply via the contact Q1 and starts emitting the detection light from the light emitting unit 45. While the shielding plate 43 of the gear 41 passes between the light emitting unit 45 and the light receiving unit 46, the light receiving unit 46 does not receive the detection light of the light emitting unit 45. In this case, the phototransistor TR of the light receiving unit 46 is in a high impedance state because no voltage is applied to the base and no current flows from the collector to the emitter.

  In contrast, while the through-hole portion 44 of the gear 41 passes between the light emitting portion 45 and the light receiving portion 46, the light receiving portion 46 receives the detection light from the light emitting portion 45. At this time, the phototransistor TR of the light receiving unit 46 outputs a detection signal (L) because a voltage is applied to the base and a current flows from the collector to the emitter.

  Here, the first to third gears 41A, 41B, and 41C have the same rotational speed, but have different numbers and width dimensions of the through-hole portions 44A, 44B, and 44C. Therefore, as shown in FIG. 8, the periods of the detection signals (L) output from the first to third sensors 42A, 42B, and 42C are different from each other.

That is, since the third gear 41C has six through holes 44C formed in the shielding valve 43C, the third sensor waveform of the third sensor 44C is “L” while the third gear 41C makes one rotation. It will output 6 times. Similarly, the first and second sensor waveforms of the first and second gears 41A and 41B output “L” once and twice, respectively.
The cycle times W1, W2, and W3 of “L” in the first to third sensor waveforms are different from each other corresponding to the width dimensions of the through holes 44A, 44B, and 44C, as shown in FIG.

  Since the first to third sensors 42A, 42B, and 42C are wired OR connected to the input unit 38a of the ASIC 38, as shown in FIG. 8, any one of the first to third sensors 42A, 42B, and 42C is “L”. Is output, the sensor input waveform input to the input unit 38a also becomes “L”.

  The sensor input waveform may contain noise due to slight signal reflection in the output line L or the like. Therefore, as shown in FIG. 8, the filter circuit 54 generates noise included in the sensor input waveform, that is, a waveform having a period equal to or less than the noise cancellation setting value set in the noise cancellation setting register 53 from the sensor input waveform. The sensor output waveform is output to the pulse width measurement circuit 56.

  The pulse width measurement circuit 56 measures the pulse width PW of “L” indicated in the sensor output waveform according to the reference clock set in the reference clock setting register 55. That is, the pulse width measurement circuit 56 uses the edge (Es) when the sensor output waveform is switched from “H” to “L” as a trigger until the sensor output waveform switches from “L” to “H” (Ee), The number of pulses is counted according to the reference clock set by the reference clock setting register 55. Then, as shown in FIG. 9, the counted number of pulses is set as a pulse width PW.

  When the pulse width PW is input from the pulse width measurement circuit 56, the first to third comparators 59A, 59B, 59C of the comparison circuit 58 convert the pulse width PW into the first to third pulse width setting registers 57A, 57B, Compare with 57C pulse width judgment value.

  As described above, different pulse width determination values (see FIG. 7) are set in the first to third pulse width setting registers 57A, 57B, and 57C. Therefore, the first comparator 59A determines whether or not the pulse width PW included in the pulse width measurement data is greater than the pulse width determination value “50” set in the first pulse width setting register 57A. The second comparator 59B determines whether or not the pulse width PW is larger than the pulse width determination value “25” set in the second pulse width setting register 57B. Further, the third comparator 59C determines whether or not the pulse width PW is larger than the pulse width determination value “10” set in the third pulse width setting register 57C.

  Then, the first to third pulse width setting registers 57A, 57B, and 57C indicate “comparison results D (2), D (1), and D (0)” when the pulse width PW is larger than the pulse width determination value. 1 ”is output, and when the pulse width PW is equal to or smaller than the pulse width determination value,“ 0 ”is output as the comparison results D (2), D (1), and D (0).

  As shown in FIG. 9, the comparison circuit 58 includes the comparison result D (0) of the third comparator 59C, the comparison result D (1) of the second comparator 59B, and the comparison result D (2) of the first comparator 59A. Are output to the pulse determination circuit 60.

  That is, the comparison circuit 58 separates the pulse width PW into three comparison results D (2), D (1), and (0), so that the pulse width PW is larger than “50” (hereinafter, “ Belonging to a first band), belonging to a band greater than “25” and less than or equal to “50” (hereinafter referred to as “second band”), or a band greater than “10” and less than or equal to “25” (hereinafter referred to as “second band”). Whether it belongs to the “third band” or “10” or less (hereinafter referred to as “fourth band”) is indicated by a three-digit value.

  The pulse determination circuit 60 determines the rotation state of the first to third motors 40A, 40B, and 40C based on the three-digit value input from the comparison circuit 58.

  Specifically, as shown in FIG. 11, when the comparison results D (2), (1), (0) of the first to third comparators 59A, 59B, 59C are all “1”. Is unreasonable because the pulse width PW belongs to the first to third bands. In this case, the pulse determination circuit 60 determines that there is a machine error, and does not write the set value “1” in the first to third sensor input registers 61A, 61B, 61C.

  When the comparison result D (2) of the first comparator 59A is “0” and the comparison results D (1) and (0) of the second and third comparators 59B and 59C are “1”, It means that the pulse width PW belongs to the first band. In this case, the pulse determination circuit 60 determines that the first sensor 42A has detected the through hole 44A of the first gear 41A, and overwrites the set value “1” in the first sensor input register 61A.

  Further, when the comparison results D (2) and (1) of the first and second comparators 59A and 59B are “0” and the comparison result D (0) of the third comparator 59C is “1”. Means that the pulse width PW belongs to the second band. In this case, the pulse determination circuit 60 determines that the second sensor 42B has detected the through hole 44B of the first gear 41B, and overwrites the set value “1” in the second sensor input register 61B.

  Further, when the comparison results D (2), (1), (0) of the first to third comparators 59A, 59B, 59C are all “0”, the pulse width PW is set to the third band. It means belonging. In this case, the pulse determination circuit 60 determines that the third sensor 42C has detected the through hole 44C of the first gear 41C, and overwrites the set value “1” in the second sensor input register 61C.

  Therefore, the CPU 34 can detect the rotation state of the first to third motors 40A, 40B, and 40C depending on whether or not the set value “1” is written in the first to third input registers 61A, 61B, and 61C.

<Motor abnormality detection operation>
Next, an operation for detecting a motor abnormality will be described with reference to FIG. FIG. 11 is a flowchart of the motor abnormality detection program 37 stored in the ROM 35 shown in FIG.
When the CPU 34 receives a print command from, for example, a personal computer (not shown), the motor abnormality detection program 37 is read from the ROM 35 and copied to the RAM 34 to detect the rotation states of the first to third motors 40A, 40B, and 40C.

  That is, the CPU 34 first starts rotating the motor 40 in step 1 (hereinafter referred to as “S1”). Since the rotation method of the motor 40 has been described above, the description thereof is omitted.

  In S2, the CPU 34 sends predetermined sensors to the first to third sensor read timers t1, t2, and t3 indicating the timing for reading the set values set in the first to third sensor input registers 61A, 61B, and 61C. The lead time set values T1, T2, and T3 are set, and rotation detection of the first to third motors 40A, 40B, and 40C is started. Since the method for detecting the rotation of the motor 40 has been described above, a description thereof will be omitted.

  Here, the “sensor lead time set values T1, T2, T3” are set according to the number of the through-hole portions 44 and the rotation speed. In this embodiment, the sensor lead time set values T1 and T2 are set to “80”, and the sensor lead time set value T3 is set to “40”.

  Then, in S3, it is determined whether or not the first sensor read timer t1 is “0”. If the first sensor read timer t1 is not “0” (S3: No), it is not the timing to read the set value of the first sensor input register 61A, so in S4, the first sensor read timer t1 is set to “t1-1. Is set to shorten the waiting time until the set value of the first sensor input register 61A is read. Then, it progresses to S5. Since the processing of S5 to S8 is the same as S3 and S4, the description thereof is omitted.

  When the first to third sensor lead timers t1, t2, and t3 are all “0” and the value of the first sensor lead timer t1 is decreased (S3: N0, S4, S5: No, S6, S7). : No, S8), in S9, it is determined whether the print data is in the RAM 36 or not. If there is print data, it is determined in S10 whether or not it is a polling cycle. In the present embodiment, the polling cycle is 5 msec.

  If 5 msec has not elapsed since the first sensor read timer t1 was read immediately before, it is determined that the polling period has not elapsed (S10: No), and the process waits as it is. On the other hand, if 5 msec has elapsed since the first sensor read timer t1 was read immediately before, it is determined that the polling cycle has elapsed (S10: Yes), the process returns to S3, and the first sensor read timer t1 is read again. The processing is continued in the same manner as described above.

  On the other hand, when the print data is not in the RAM 36 (S9: No), it is not necessary to rotate the first to third motors 40A, 40B, and 40C. In S11, the first to third motors 40A, 40C, The rotation of 40B and 40C is stopped. Thereafter, the process ends.

  By the way, when the processes of S1 to S10 are repeated and the third sensor lead timer t3 is counted down from the sensor lead time set value T3 (“40” in the present embodiment) to “0” (S3: No, S4, (S5: No, S6, S7: Yes) In S18, the set value of the third sensor input register 61C is read. Then, in S19, the CPU 34 determines whether or not the setting value read from the third sensor input register 61C is “1”.

  When the CPU 34 determines that the set value read from the third sensor input register 61C is “1” (S19: Yes), it overwrites “0” in the third sensor input register 61C in S20. At the same time, the CPU 34 sets the sensor lead time set value T3 in the third sensor lead timer t3. Thereby, next, the third sensor 42C is ready to detect the through hole 44C of the third gear 41C. Thereafter, the CPU 34 proceeds to S9 and continues the process.

  On the other hand, when the CPU 34 determines that the set value of the third sensor input register 61C is not “1” (S19: No), it detects an error in S21. Since the third sensor input register 61C stores the rotation state of the third motor 40C, the CPU 34 determines that a rotation error (abnormality) has occurred in the third motor 40C.

  Then, the CPU 34 stops the printing of the printer 1 in S22. In S23, the CPU 34 warns that a machine error has occurred in the third motor 40C. The warning may be performed using a display unit such as a liquid crystal panel or a warning lamp provided in the printer 1, or may be performed by generating a sound or a buzzer sound from a speaker built in the printer 1. When the machine error is warned in this way, the CPU 34 ends the process.

  When the first or second sensor lead timer t1, t2 counts down from the sensor lead time set value T1, T2 (“80” in this embodiment) to “0” (S3: Yes, S5: Yes) Whether or not the first and second motors 40A and 40B are abnormal is determined in the same manner as the abnormality detection process (S18 to S19) of the third motor 40C (S12, S13, S15, and S16). The corresponding processing is executed as in the case of the third motor 40C (S20 to S23) (see S14, S17, S21 to S23).

  The motor abnormality detection device 19 detects the rotation state of the first to third motors 40A, 40B, and 40C during the printing operation by repeating the above processing.

<Effect>
In the motor abnormality detection device 19 and the printer 1 of the present embodiment, the first to third gears 41A in which the first to third sensors 42A, 42B, and 42C are rotationally driven by the first to third motors 40A, 40B, and 40C. , 41B, and 41C output detection signals that change from “H” to “L” by the through holes 44A, 44B, and 44C.

  Since the first to third sensors 42A, 42B, and 42C are OR-connected to the input unit 38a of the ASIC 38 that constitutes the control unit 10, the detection signals output from the first to third sensors 42A, 42B, and 42C However, since the periods (change states) W1, W2, W3 (see FIG. 8) of the detection signals output from the sensors 42A, 42B, 42C are different, they are input to the input unit 38a. Based on the detection signal, the rotation states of the first to third motors 40A, 40B, and 40C can be detected. Therefore, even if the number of motors increases, the number of input units 38a does not increase, and the control unit 10 can be downsized.

  Therefore, according to the motor abnormality detection device 19 and the printer 1 of the present embodiment, the detection accuracy can be stabilized while reducing the number of input units 38a.

  Further, the motor abnormality detection device 19 of the present embodiment separates the detection signal input to the input unit 38a in the comparison circuit 56 and converts it into a signal indicating the rotation state of each motor 40A, 40B, 40C (FIG. 9). Reference), even if a sum (sensor input waveform) of a plurality of detection signals (first to third sensor waveforms) is input to the input unit 38a, it is separated and the first to third motors 40A, 40B, 40C are separated. The rotation state of each can be detected individually.

  Moreover, since the motor abnormality detection device 19 of the present embodiment is provided with the through-hole portion 44 in the gear 41, a mechanism for detecting the rotation of the motor 40 can be provided inexpensively and compactly.

  In addition, the motor abnormality detection device 19 of the present embodiment detects a detection signal (L) that the third sensor 42C detects and outputs the through hole 44C of the third gear 41C corresponding to the third motor 40C that drives the heating roller 28. ) Is shorter than the period (change time) of the detection signals (L) output from the other first and second sensors 42A and 42B, so that the heating roller 28 is not attached to the pressing roller 29. The abnormality of the third motor 40C that drives the heating roller 28 can be quickly detected.

  Moreover, since the 1st-3rd sensor 42A, 42B, 42C is wired OR connected to the input part 38a, the motor abnormality detection apparatus 19 of this embodiment can suppress the number of elements used for a circuit.

Although the embodiments of the present invention have been described, the present invention is not limited to the above-described embodiments, and various applications are possible.
(1) In the said embodiment, the through-hole part 44 was formed in slit shape. On the other hand, the shape of the through-hole portion may be a through-hole such as a circle, an ellipse, or a quadrangle.

(2) In the above embodiment, the rotation of the gear 41 is detected by the photoelectric sensor 42. On the other hand, the sensor for detecting the rotation of the gear 41 is not limited to this. For example, a magnet is attached to the position of the through-hole portion 44, and a sensor for detecting magnetism is disposed on the gear 41. You may make it detect rotation.

(3) The first to third comparators 59A, 59B, and 59C output a minus signal when the pulse width included in the pulse width measurement data is equal to or greater than the pulse width determination value depending on how the circuits are connected, and the pulse When the pulse width included in the width measurement data is less than the pulse width determination value, a plus signal may be output.

(4) In the embodiment described above, the first to third gears 41A, 41B, 41C in which the first to third sensors 42A, 42B, 42C are arranged are used as the arrangement switching device 18, the conveyor belt drive roller 6, and the heating roller 28. Although it was set as the last gear connected, the 1st-3rd sensors 42A, 42B, and 42C are the 1st-3rd motors 40A and 40B from the motor shaft of the 1st-3rd motors 40A, 40B, and 40C to the last gear. , 40C may be arranged at a position where rotation can be detected.

(5) In the above embodiment, the printer 1 is used as an example of the image forming apparatus. On the other hand, the motor abnormality detection device 19 may be applied by taking a multifunction device, a facsimile machine, a copier or the like as an example of an image forming apparatus. Further, the usage destination of the motor abnormality detection device 19 is not limited to the image forming apparatus, and may be applied to an electric product including a plurality of motors.

(6) In the above embodiment, the gear 41 is a rotating body. On the other hand, a rotating body may be provided separately from the components of the printer 1 and attached to a gear or the like.
(7) In the above embodiment, the first to third pulse width setting registers 57A, 57B, and 57C are provided corresponding to the first to third comparators 59A, 59B, and 59C. On the other hand, one pulse width setting register may be connected to the first to third comparators 59A, 59B, 59C to output different pulse width determination values.

(8) In the above embodiment, the first to third sensors 42A, 42B, and 42C are wired or connected to the input unit 38a. On the other hand, the wired OR connection is changed to an AND circuit or an OR circuit, and the detection signals of the first to third sensors 42A, 42B, 42C are combined into one and input to the input unit 38a. Also good.

(9) In the above embodiment, the rotational state of the motor 40 is detected based on the detection signal (L) output from the sensor 42 when the through-hole portion 44 is detected. On the other hand, the rotation state of the motor 40 may be detected based on the detection signal (H) in the high state that is input to the input unit 38a when the sensor 42 is detecting the shielding valve 43.

(10) In the above embodiment, the through holes 44A, 44B, 44C are provided in the first to third gears 41A, 41B, 41C so that the period (detection time) of the detection signal (L) is different. In contrast, the through holes 44A, 44B, and 44C of the first to third gears 41A, 41B, and 41C may be provided so as to change the duty ratio of “H” and “L”.

1 is a diagram illustrating an internal configuration of a printer that is an example of an “image forming apparatus” according to an embodiment of the present invention. FIG. It is a schematic block diagram of the motor abnormality detection apparatus shown in FIG. It is an external appearance perspective view which shows the 3rd gear arrange | positioned at the 3rd gear shown in FIG. 2, and its 3rd gear. It is a schematic block diagram of the 1st gear shown in FIG. It is a schematic block diagram of the 2nd gear shown in FIG. FIG. 3 is a logic diagram showing an internal configuration of the ASIC shown in FIG. 2. It is a figure which shows an example of the pulse width determination value set by the 1st-3rd pulse width setting register | resistor shown in FIG. The sensor waveform output by the first to third sensors shown in FIG. 2, the sensor input waveform input by the filter circuit shown in FIG. 6, the sensor output waveform output by the filter circuit, and the noise cancellation setting register output to the filter circuit It is a figure which shows the waveform of the reference | standard clock signal to do. It is a figure which shows the sensor input pulse measurement data which the pulse width measurement circuit shown in FIG. 6 outputs, and the sensor input comparison data which a comparison circuit outputs. It is a figure which shows the determination by the pulse discrimination circuit shown in FIG. It is a flowchart of the motor abnormality detection program memorize | stored in ROM shown in FIG.

Explanation of symbols

1 Printer (image forming device)
3 Recording paper 6 Conveyor belt drive roller (an example of parts)
10 Control unit (an example of rotation detection means)
18 Arrangement switching device (example of parts)
19 Motor abnormality detection device 28 Heating roller (an example of parts)
29 Press roller 38a Input part 40A, 40B, 40C 1st-3rd motor 41A, 41B, 41C 1st-3rd gear (an example of a rotary body)
42A, 42B, 42C 1st-3rd sensor (an example of a sensor means)
44A, 44B, 44C Through-hole portion 58 Comparison circuit (an example of separation means)

Claims (6)

In a motor abnormality detection device that detects rotation abnormality of a plurality of motors,
A plurality of rotating bodies that are arranged corresponding to the plurality of motors, are driven to rotate by the corresponding motors, and each have a through hole portion;
A plurality of sensor means arranged corresponding to the plurality of rotating bodies and outputting detection signals that change depending on the through-holes;
Rotation detection means for detecting rotation states of the plurality of motors based on detection signals from the plurality of sensor means; and
The through holes are provided so that the change states of detection signals output from the plurality of sensor means are different from each other when the plurality of motors normally rotate, and the plurality of sensor means are input to the rotation detection means. A motor abnormality detection device characterized by being OR-connected to the section. In the motor abnormality detection device according to claim 1,
The rotation detecting means includes
A motor abnormality detection device comprising separation means for separating a detection signal input to the input unit. In the motor abnormality detection device according to claim 1 or 2,
The motor abnormality detection device, wherein the rotating body is constituted by a gear coupled to the motor. In the motor abnormality detection device according to any one of claims 1 to 3,
Used in an image forming apparatus configured to convey a recording sheet supplied with a developer between a heating roller and a pressure roller and heat-fix the developer on the recording sheet;
One of the motors is for driving the heating roller, and the through hole portion of the rotating body corresponding to the motor is output from the sensor means arranged corresponding to the rotating body. The motor abnormality detection device is provided so that the change time of the detection signal is shorter than the change time of the detection signal output from the other sensor means. In the motor abnormality detection device according to any one of claims 1 to 4,
The motor abnormality detection device, wherein the plurality of sensor means are wired OR connected to the input unit. An image forming apparatus comprising the motor abnormality detection device according to any one of claims 1 to 5.

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