JP5624968B2 - Image forming apparatus - Google Patents

Description

  The present invention relates to an image forming apparatus including a rotating member and a drive unit that drives the rotating member.

  The image forming apparatus includes a rotating member (roller) and a drive unit (motor) that drives the roller. The roller and the motor constitute, for example, a fixing unit. Specifically, the roller is used as a pressure roller in the fixing unit. The motor is driven to rotate the pressure roller. The fixing unit includes an endless fixing film that can be rotated by frictional force with the pressure roller, a heater that heats the fixing film, a sensor that detects the rotation speed of the fixing film, and a rotation speed detected by the sensor. And a control unit that adjusts the rotation speed of the fixing film by controlling the motor based on the above. Such a fixing unit determines that the fixing film is slipped and the rotation of the fixing film is stopped when the rotation speed of the fixing film based on the detection result of the sensor is equal to or less than a predetermined value. The fixing film is prevented from being thermally damaged due to excessive temperature rise (see Patent Document 1).

JP 2011-48134 A

  However, in the fixing unit described in Patent Document 1, even when the rotation of the fixing film is stopped due to a motor failure, it is determined that there is an abnormality in the fixing film. As described above, in the fixing unit described in Patent Document 1, it is determined that the cause of the failure is the fixing film. Therefore, it is determined that the failure point is a motor and it takes time to repair the failure. There is a problem that it takes.

  SUMMARY An advantage of some aspects of the invention is that it provides an image forming apparatus capable of specifying which of a rotating member and a drive unit is out of order.

  The present invention relates to a rotating member that rotates, a driving unit that outputs an output signal based on driving, and a rotational speed of the rotating member, to drive the rotating member based on an input signal so as to rotate the rotating member. And determining whether or not there is a difference between the frequency of the input signal and the frequency of the output signal, and a drive control unit that controls the drive unit based on supplying the input signal to the drive unit And a first counting unit for increasing a first count value when the determination unit determines that there is a difference between the frequency of the input signal and the frequency of the output signal. A first determination unit that determines that the drive unit is malfunctioning when the first count value is greater than a first abnormality determination value that is set in advance, The drive control unit controls the drive unit. When the rotation speed of the rotating member is changed based on the difference between the first rotation speed that is the changed rotation speed and the second rotation speed that is the rotation speed before the change. The present invention relates to an image forming apparatus that returns the first count value to an initial value when an absolute value exceeds a predetermined value.

  The predetermined value is preferably a rotation speed that is 4 to 8% of the second rotation speed.

  An image forming apparatus includes: a detection unit that detects rotation of the rotation member; a second count unit that increases a second count value when rotation of the rotation member is not detected by the detection unit; and the second count unit It is preferable to further include a second determination unit that determines that there is an abnormality in the rotating member when the second count value counted in step (b) exceeds a preset second abnormality determination value.

  The drive control unit is configured to perform the drive when the first determination unit determines that the drive unit is out of order, or when the second determination unit determines that the rotating member is abnormal. It is preferable to stop the driving of the part.

  The rotating member is preferably a fixing roller disposed in a fixing unit that heats and pressurizes the transfer material and toner to fix the toner to the transfer material.

  An object of the present invention is to provide an image forming apparatus that can easily identify a failure location.

1 is a diagram illustrating an overall configuration of a copier according to an embodiment of an image forming apparatus. It is a figure for demonstrating a fixing part. 2 is a block diagram illustrating a functional configuration of a copier. FIG. 6 is a first flowchart for explaining the operation of the copier. It is a 2nd flowchart for demonstrating operation | movement of a copier.

  A copier according to an embodiment of an image forming apparatus of the present invention will be described below with reference to the drawings. First, the overall configuration of the copy machine 1 will be described. FIG. 1 is a diagram for explaining an overall configuration of a copier 1 according to an embodiment of an image forming apparatus. FIG. 2 is a diagram for explaining the fixing unit 60.

As shown in FIG. 1, the copier 1 of the present embodiment includes a document transport unit 10, a document reading unit 20, a paper transport unit 30, an image forming unit 40, a transfer unit 50, and a fixing unit 60. Prepare.
The document transport unit 10 is an ADF (Automatic Document Feeder), and includes a document placement unit 11, a first feed roller 12, a guide 13, a timing roller pair 14, and a document discharge unit 15. The first feed roller 12 supplies the document G placed on the document placement unit 11 to the timing roller pair 14 one by one in order. The timing roller pair 14 is a timing at which the document reading unit 20 reads an image of the document G and a timing at which the document G is supplied to a position where the image of the document G is read by the document reading unit 20 (a position where the guide 13 is disposed). In order to match, the conveyance of the original G or the conveyance stop of the original G is performed. The guide 13 guides the conveyed document G to a first reading surface 21a described later. The document discharge unit 15 discharges the document G from which an image has been read by the document reading unit 20 (passed through the guide 13) to the outside of the copier 1.
A document stacking unit 16 is formed on the upper surface of the copier 1 outside the document discharge unit 15. In the document stacking unit 16, the documents G discharged from the document discharge unit 15 are stacked and stacked.

  The document reading unit 20 includes a first reading surface 21a and a second reading surface 22a. The first reading surface 21 a is formed along the upper surface of the first contact glass 21 disposed so as to face the guide 13, and serves as a surface for reading an image of the document G conveyed by the document conveying unit 10. The second reading surface 22a is disposed adjacent to the first reading surface 21a (in the case shown in FIG. 1, over the most right side of the first reading surface 21a). The second reading surface 22 a is used when reading an image of the document G without using the document transport unit 10. The second reading surface 22a is formed along the upper surface of the second contact glass 22 on which the document G is placed, and serves as a surface for reading an image of the document G placed on the second reading surface 22a.

  The document reading unit 20 includes an illumination unit 23, a first mirror 24, a second mirror 25, a third mirror 26, an imaging lens 27, and an imaging unit 28 inside the copier 1. The illumination unit 23 and the first mirror 24 move in the sub-scanning direction X, respectively. The second mirror 25 and the third mirror 26 are disposed on the left side of the illumination unit 23 and the first mirror 24 in FIG. Further, the second mirror 25 and the third mirror 26 are the first reading surface 21 a or the second reading surface 22 a through the first mirror 24, the second mirror 25, the third mirror 26, and the imaging lens 27. To the imaging unit 28 while moving in the sub-scanning direction X while keeping the distance (optical path length) constant.

  The illumination unit 23 is a light source that irradiates the original G with light. The first mirror 24, the second mirror 25, and the third mirror 26 are mirrors for guiding the light reflected by the document G to the imaging lens 27 while keeping the optical path length constant. The imaging lens 27 focuses the light incident from the third mirror 26 on the imaging unit 28. The imaging unit 28 is an imaging device for obtaining image data based on an imaged optical image by converting incident light into an electrical signal. For example, the imaging unit 28 is a CCD (Charge Coupled Device) or a CMOS (Complementary). It is an image sensor such as Metal Oxide Semiconductor).

The paper transport unit 30 includes a second feed roller 31, a third feed roller 32, a registration roller pair 33, and a paper discharge unit 34. The second feed roller 31 supplies the paper T (transfer material) stored in the paper feed cassette 36 to the registration roller pair 33. The third feed roller 32 supplies the paper T (transfer material) placed on the manual feed tray 37 to the registration roller pair 33. The registration roller pair 33 performs the conveyance of the paper T or the conveyance stop of the paper T in order to match the timing when the toner image reaches the transfer unit 50 and the timing when the paper T is supplied to the transfer unit 50. Further, the registration roller pair 33 performs skew (oblique feeding) correction of the paper T. The paper discharge unit 34 discharges the paper T onto which the toner image has been transferred by a transfer unit 50 described later and the toner image has been fixed by a fixing unit 60 described later to the outside of the copier 1.
A paper discharge stacking unit 35 is formed outside the paper discharge unit 34. In the paper discharge stacking unit 35, the paper T discharged from the paper discharge unit 34 is stacked and stacked.

The image forming unit 40 is for forming a toner image. The image forming unit 40 includes a photosensitive drum 41, a charging unit 42, a laser scanner unit 43, a developing device 44, a cleaning unit 45, a toner cartridge 46, 1 A next transfer roller 47, an intermediate transfer belt 48, and a counter roller 49 are provided.
The photoconductor drum 41 (41a, 41b, 41c and 41d) functions as a photoconductor or an image carrier in order to form toner images of black, cyan, magenta and yellow, respectively. Around each photosensitive drum 41a, 41b, 41c, 41d, in order from the upstream side to the downstream side along the rotation direction of the photosensitive drum 41, a charging unit 42, a laser scanner unit 43, a developing device 44, A cleaning unit 45 is disposed. The charging unit 42 charges the surface of the photosensitive drum 41. The laser scanner unit 43 is arranged apart from the surface of the photosensitive drum 41 and scans and exposes the surface of the photosensitive drum 41 based on image data relating to the original G read by the original reading unit 20. As a result, an electrostatic latent image is formed on the surface of the photosensitive drum 41 by removing the charge of the exposed portion. The developing device 44 forms a toner image by attaching toner to the electrostatic latent image formed on the surface of the photosensitive drum 41. After the toner image formed on the surface of the photosensitive drum 41 is primarily transferred by a primary transfer roller 47 described later, the cleaning unit 45 discharges the surface of the photosensitive drum 41 by a static eliminator (not shown). Then, the toner remaining on the surface of the photosensitive drum 41 is removed.
The toner cartridge 46 stores toner of each color supplied to the developing device 44. The toner cartridge 46 and the developing device 44 are connected by a toner supply path (not shown).

  The primary transfer rollers 47 (47a, 47b, 47c, and 47d) are disposed on the opposite sides of the intermediate transfer belt 48 from the photosensitive drums 41a, 41b, 41c, and 41d, respectively. The intermediate transfer belt 48 is a belt that passes through the image forming unit 40 and the transfer unit 50. A part of the intermediate transfer belt 48 is sandwiched between the respective photosensitive drums 41a, 41b, 41c and 41d and the respective primary transfer rollers 47a, 47b, 47c and 47d, and the respective photosensitive drums 41a, 41b and 41c. The toner images formed on the surfaces of 41 and 41d are primarily transferred. The opposing roller 49 is a driving roller that is disposed inside the intermediate transfer belt 48 having an annular shape, and advances the intermediate transfer belt 48 in the direction of arrow A shown in FIG.

  The transfer unit 50 includes a secondary transfer roller 51. The secondary transfer roller 51 is disposed on the side opposite to the counter roller 49 with respect to the intermediate transfer belt 48, and a part of the intermediate transfer belt 48 is sandwiched between the counter roller 49. Further, the secondary transfer roller 51 secondarily transfers the toner image primarily transferred to the intermediate transfer belt 48 onto the paper T.

  As shown in FIGS. 1 and 2, the fixing unit 60 includes a roller (rotating body) that rotates as a rotating member. Specifically, the fixing unit 60 includes a heating roller (heating rotator) 61 and a pressure roller (pressure rotator) 62. The heating roller 61 and the pressure roller 62 are fixing rollers 60 </ b> A that heat and press the paper T and toner to fix the toner to the paper T. That is, the heating roller 61 and the pressure roller 62 sandwich the paper T on which the toner image is secondarily transferred, melt and press the toner, and fix the toner to the paper T.

  The fixing unit 60 includes a motor 63 as a driving unit and a detection unit 64. The motor 63 is driven based on the input signal so as to rotate the heating roller 61 or the pressure roller 62. For example, the motor 63 is driven at a rotation speed corresponding to the frequency of the input signal. The input signal is supplied from a drive control unit 91 of the control unit 90 described later. The motor 63 outputs an output signal based on driving. For example, the motor 63 outputs an output signal having a frequency corresponding to the number of rotations during driving. The output signal is supplied to a determination unit 92 of the control unit 90 described later. The output signal may be output from a rotation speed measurement unit (not shown) arranged outside the motor 63. The rotation point number measurement unit measures the rotation speed when the motor 63 is driven, and outputs an output signal having a frequency corresponding to the rotation speed.

  Here, the motor 63 may be driven to rotate each of the heating roller 61 and the pressure roller 62, or may be driven to rotate only one of the heating roller 61 and the pressure roller 62. Good. When the motor 63 is driven to rotate only one of the heating roller 61 and the pressure roller 62, the other roller is driven to rotate based on contact with the one roller.

  The detection unit 64 detects whether the heating roller 61 or the pressure roller 62 is rotating. The detection unit 64 includes, for example, a pulse plate (not shown) and an optical sensor (not shown). The pulse plate is, for example, circular and includes a plurality of holes (not shown) in the circumferential direction. The pulse plate is disposed on the rotation shaft of the heating roller 61 or the pressure roller 62 and rotates with the rotation of the rollers 61 and 62. The optical sensor includes a light emitting unit (not shown) and a light receiving unit (not shown). The light emitting unit and the light receiving unit are arranged so as to face each other through a pulse plate (a region where a hole is provided). That is, when the pulse plate rotates, the light emitted from the light emitting unit passes through the hole plate through the hole and is blocked by the pulse plate. Therefore, the light receiving unit repeats light reception and non-light reception of the light emitted from the light emitting unit. The detection unit 64 detects that the heating roller 61 or the pressure roller 62 is rotating when light reception and non-light reception are repeatedly detected by the light receiving unit.

Next, the functional configuration of the copy machine 1 will be described. FIG. 3 is a block diagram showing a functional configuration of the copy machine 1.
The copier 1 includes the above-described components (the document transport unit 10, the document reading unit 20, the paper transport unit 30, the image forming unit 40, the transfer unit 50, and the fixing unit 60). The engine unit 3 is configured by the paper transport unit 30, the image forming unit 40, the transfer unit 50, and the fixing unit 60. Note that the description of the components described with reference to FIG. 1 is omitted.
Further, the copier 1 includes an operation unit 70, a storage unit 80, and a control unit 90 in addition to the functional configuration described above.

  The operation unit 70 includes a numeric keypad (not shown), a touch panel (not shown), a start key (not shown), and the like. The numeric keypad is operated to input numbers such as the number of copies to be printed. The touch panel displays a plurality of keys to which various functions (for example, a function for setting a print magnification and a function for allocating a plurality of pages to one sheet of paper T (such as 2 in 1)) are assigned. A key displayed on the touch panel is operated to cause the copier 1 to execute any of various functions. The start key is operated to execute printing. When any key is operated, the operation unit 70 supplies a signal indicating that this key has been operated to the control unit 90.

  The storage unit 80 includes a hard disk, a semiconductor memory, and the like. The storage unit 80 stores image data of the original G read by the original reading unit 20. Further, the storage unit 80 stores a control program used in the copier 1, data used by the control program, and the like.

The control unit 90 controls the document conveying unit 10, the document reading unit 20, the engine unit 3, the operation unit 70, and the like.
The control unit 90 includes a drive control unit 91, a determination unit 92, a first counting unit 93, a first determination unit 94, a second counting unit 95, and a second determination unit 96.

The drive control unit 91 controls the motor 63 based on supplying an input signal to the motor 63 in order to control the rotation of the heating roller 61 or the pressure roller 62. Further, the drive control unit 91 changes the rotation speed (rotation number) of the heating roller 61 or the pressure roller 62 based on control to change the rotation number of the motor 63. The drive controller 91 supplies the motor 63 with an input signal having a frequency corresponding to the constant rotational speed in order to rotate the motor 63 at a constant rotational speed. Further, the motor 63 outputs an output signal having a frequency corresponding to the number of rotations actually rotating to the determination unit 92.
Further, the drive control unit 91 determines that the motor 63 is malfunctioning by the first determination unit 94 to be described later, or that the heating roller 61 or the pressure roller 62 has an abnormality by the second determination unit 96 to be described later. When it is determined that there is, the driving of the motor 63 is stopped.

  The determination unit 92 determines whether or not there is a difference between the frequency of the input signal from the drive control unit 91 to the motor 63 and the frequency of the output signal from the motor 63 to the determination unit 92. Here, when the drive control unit 91 supplies the motor 63 with an input signal having a frequency corresponding to the constant rotational speed so that the motor 63 rotates at the constant rotational speed, the motor 63 is based on the input signal. When actually rotating at the constant rotational speed and outputting an output signal having a frequency corresponding to the constant rotational speed, the determination unit 92 has no difference between the frequency of the input signal and the frequency of the output signal. Judge.

  On the other hand, when changing the rotational speed based on the input signal, the motor 63 outputs an output signal having a frequency that continuously changes in accordance with the continuously changing rotational speed. For this reason, in order for the drive control part 91 to change the rotation speed of the motor 63, based on having supplied the motor 63 with the input signal of the frequency according to the rotation speed after change, the motor 63 makes rotation speed continuous. In the case where an output signal having a frequency that continuously changes in accordance with the rotation speed is output to the determination unit 92, the determination unit 92 has a difference between the frequency of the input signal and the frequency of the output signal. Judge that there is.

  Further, the motor 63 outputs a constant (for example, “0”) output signal when it is not driven due to a failure. Therefore, when the drive control unit 91 supplies the motor 63 with an input signal having a frequency corresponding to the predetermined rotational speed so that the motor 63 rotates at the predetermined rotational speed, the motor 63 is not driven due to a failure. When outputting a constant output signal, the determination unit 92 determines that there is a difference between the frequency of the input signal and the frequency of the output signal.

  The first counting unit 93 increases the first count value when the determining unit 92 determines that there is a difference between the frequency of the input signal and the frequency of the output signal. That is, the first counting unit 93 increases the first count value by one every time the determining unit 92 determines that there is a difference between the frequency of the input signal and the frequency of the output signal.

  The first counting unit 93 is the rotation speed after the change when the rotation speed of the heating roller 61 or the pressure roller 62 is changed based on the drive control unit 91 controlling the motor 63. When the absolute value of the difference between the first rotation speed and the second rotation speed that is the rotation speed before the change exceeds a predetermined value (threshold value), the first count value is returned to the initial value.

  In addition, when changing the rotational speed of the heating roller 61 or the pressure roller 62, the motor 63 is controlled by the drive controller 91, so that the rotational speed of the motor 63, that is, the driving speed of the motor 63 is changed. Is done. Therefore, when the absolute value of the difference between the first rotation speed and the second rotation speed performed by the first counting unit 93 exceeds a predetermined value, the first measured value is returned to the initial value. Alternatively, when the drive control unit 91 controls the motor 63 so as to change the rotation speed of the pressure roller 62, the rotation speed of the motor 63 corresponding to the change after the rotation speed of the heating roller 61 or the pressure roller 62 is changed. When the absolute value of the difference between one rotation number and the second rotation number that is the rotation number of the motor 63 corresponding to the rotation speed of the heating roller 61 or the pressure roller 62 before the change exceeds the threshold, the first meter It is similar to returning the numerical value to the initial value.

  Here, the heating roller 61 and the pressure roller 62 are expanded or contracted by heat. When the heating roller 61 and the pressure roller 62 are expanded or contracted, the conveyance speed of the paper T changes if the rotation speeds of the rollers 61 and 62 are constant. For this reason, in order to make the conveyance speed of the paper T constant even when the heating roller 61 and the pressure roller 62 are expanded or contracted, the drive control unit 91 changes the number of rotations of the motor 63 slightly slightly. Yes.

  Therefore, the first counting unit 93 relatively slightly changes the rotation speed of the heating roller 61 or the pressure roller 62 based on the drive control unit 91 changing the rotation number of the motor 63 relatively slightly. When (when changing the rotation speed of the pressure roller 62 or the pressure roller 62 in order to keep the conveyance speed of the paper T constant), when the range of the rotation speed change is within the threshold range, The first measurement value is not returned to the initial value. Thereby, the count for determining the failure of the motor 63 is continued. On the other hand, the first counting unit 93 returns the first measurement value to the initial value when the range of change in the rotation speed (difference between the first rotation speed and the second rotation speed) exceeds the threshold value. Thereby, the count for determining the failure of the motor 63 is started again from the beginning.

  More specifically, the reference value (the above-described threshold value) for determining whether or not to return the first measurement value to the initial value is a rotation speed that is ± 4 to ± 8% of the second rotation speed. That is, the predetermined value is a rotational speed that is ± 4 to ± 8% of the second rotational speed. More preferably, the predetermined value is a rotational speed that is ± 6% of the second rotational speed. Therefore, the threshold value described above is a rotational speed that is ± 4 to ± 8% of the second rotational speed. More preferably, the threshold value is a rotational speed that is ± 6% of the second rotational speed. The initial value is “0”.

  The first determination unit 94 determines that the motor 63 has failed when the first count value counted by the first count unit 93 exceeds a preset first abnormality determination value. The first abnormality determination value is a reference value (threshold value) for determining whether or not the motor 63 has failed.

  The second counting unit 95 increases the second count value when the detection unit 64 does not detect the rotation of the heating roller 61 or the pressure roller 62. That is, the second counting unit 95 increases the second count value by one each time the detection unit 64 does not detect the rotation of the heating roller 61 or the pressure roller 62.

  The second determination unit 96 determines that the heating roller 61 or the pressure roller 62 is abnormal when the second count value counted by the second counting unit 95 exceeds a preset second abnormality determination value. . The second abnormality determination value is a reference value (threshold value) for determining whether the heating roller 61 or the pressure roller 62 has an abnormality.

  Next, the operation of the copy machine 1 in this embodiment will be described. FIG. 4 is a first flowchart for explaining the operation of the copier 1. FIG. 5 is a second flowchart for explaining the operation of the copier 1.

  In step ST <b> 1 shown in FIG. 4, the first counting unit 93 determines whether or not the drive control unit 91 has changed the drive speed of the motor 63. That is, the first counting unit 93 determines whether the rotation speed of the heating roller 61 or the pressure roller 62 has been changed based on the drive control unit 91 controlling the driving speed (rotation speed) of the motor 63. To do. When the drive control unit 91 changes the drive speed of the motor 63 (Yes), the process proceeds to step ST2. If the drive control unit 91 has not changed the drive speed of the motor 63 (No), the process proceeds to step ST3.

  In step ST2, the first counting unit 93 determines whether or not the absolute value of the difference between the new speed and the old speed exceeds a speed that is 6% of the old speed. That is, the first counting unit 93 determines whether or not the absolute value of the difference between the first rotation speed and the second rotation speed exceeds a predetermined value (threshold value). When the absolute value of the difference between the new speed and the old speed exceeds the speed that is 6% of the old speed (Yes in step ST2), the process proceeds to step ST3. If the difference between the new speed and the old speed does not exceed the speed that is 6% of the old speed (No in step ST2), the process proceeds to step ST5.

  In step ST3, the first counting unit 93 sets the first count value to an initial value. Then, the process proceeds to step ST4.

  In step ST4, the second counting unit 95 sets the second count value to an initial value. After step ST4, the process proceeds to step ST5 shown in FIG.

  In step ST <b> 5, the determination unit 92 determines whether there is a difference between the frequency of the input signal input to the motor 63 and the frequency of the output signal output from the motor 63. If there is a difference between the input frequency and the output frequency (Yes), the process proceeds to step ST6. If there is no difference between the input frequency and the output frequency (No), the process proceeds to step ST9.

  In step ST6, the first counter 93 increases the first count value by one.

  In step ST7, the first determination unit 94 determines whether or not the first count value counted by the first count unit 93 exceeds the first abnormality determination value. When the first count value exceeds the first abnormality determination value (Yes), the process proceeds to step ST8. If the first count value does not exceed the first abnormality determination value (No), the process proceeds to step ST10.

  In step ST8, the first determination unit 94 determines that the motor 63 has failed. After step ST8, the process proceeds to step ST17.

  When it is determined as “No” in Step ST5, in Step ST9, the first counting unit 93 sets the first counted value to an initial value.

  In step ST <b> 10, the detection unit 64 determines whether the rotation of the heating roller 61 or the pressure roller 62 has been detected. When the rotation of the heating roller 61 or the pressure roller 62 cannot be detected (No), the process proceeds to step ST11. When the rotation of the heating roller 61 or the pressure roller 62 can be detected (Yes), the process proceeds to step ST14.

  In step ST11, the second counter 95 increases the second count value by one.

  In step ST12, the second determination unit 96 determines whether or not the second count value counted by the second count unit 95 exceeds the second abnormality determination value. When the second count value exceeds the second abnormality determination value (Yes), the process proceeds to step ST13. If the second count value does not exceed the second abnormality determination value (No), the process proceeds to step ST15.

  In step ST <b> 13, the second determination unit 96 determines that there is an abnormality in the heating roller 61 or the pressure roller 62.

  If “No” is determined in step ST10, in step ST14, the second counting unit 95 sets the second count value to an initial value.

  When it is determined as “No” in step ST12 and after step ST14, in step ST15, the determination unit 92 waits for a predetermined time (for example, 10 ms).

  In step ST16, the control unit 90 determines whether or not a predetermined number of prints have been completed. If the predetermined number of prints has not been completed (No), the process returns to step ST5. When the predetermined number of sheets have been printed (Yes), the process ends.

In step ST17, which is processing after step ST8 and step ST13, the control unit 90 (specifically, a fixing control unit (not shown) that controls the fixing unit 60) stops the fixing unit 60. In addition, when it is determined in step ST8 that the motor 63 is out of order, the fixing control unit displays on the touch panel that the motor 63 is out of order. Further, when it is determined in step ST13 that the heating roller 61 or the pressure roller 62 is abnormal, the control unit 90 (fixing control unit) displays on the touch panel that the heating roller 61 or the pressure roller 62 is abnormal. Let
After step ST17, the process ends.

As described above, according to the copying machine 1 of the present embodiment, the following effects are produced.
That is, in the copier 1 of the present embodiment, when the first determination unit 94 causes the motor 63 to malfunction when the first count value counted by the first count unit 93 exceeds a preset first abnormality determination value. On the other hand, when the second determination unit 96 determines that the second count value counted by the second count unit 95 exceeds a preset second abnormality determination value, the heating roller 61 or the pressure roller It is determined that 62 is abnormal. Thereby, the copying machine 1 can determine whether the motor 63 is out of order or whether the heating roller 61 or the pressure roller 62 is abnormal. That is, the copy machine 1 can easily identify a failure (abnormal) part.

  In the copying machine 1, after the first counting unit 93 is changed when the rotation speed of the heating roller 61 or the pressure roller 62 is changed based on the drive control unit 91 controlling the motor 63. When the absolute value of the difference between the first rotation speed that is the first rotation speed and the second rotation speed that is the rotation speed before the change exceeds a predetermined value, the first count value is returned to the initial value.

  That is, when the absolute value of the difference between the first rotation speed and the second rotation speed does not exceed a predetermined value, the copier 1 continues to monitor the failure of the motor 63, and the first rotation speed and the first rotation speed When the absolute value of the difference from the two rotation speeds exceeds a predetermined value, the failure monitoring of the motor 63 is started again. As a result, in the copying machine 1, the rotational speed of the heating roller 61 or the pressure roller 62 is relatively slightly changed based on the relatively small change in the rotational speed (drive speed) of the motor 63. In the case where the motor 63 is continuously detected, it can be determined whether or not the motor 63 has failed. In other words, the copying machine 1 can determine that the motor 63 has failed even when the rotational speed of the motor 63 is changed. On the other hand, when the rotational speed of the heating roller 61 or the pressure roller 62 is changed relatively greatly based on the fact that the rotational speed of the motor 63 is changed relatively large, the copying machine 1 is configured to use the motor 63. Therefore, it is possible to prevent erroneous determination that the motor 63 is out of order.

In addition, this invention is not limited to embodiment mentioned above, It can implement with a various form.
In the embodiment described above, the case where the present invention is applied to the fixing unit 60 has been described. However, the present invention can be applied not only to the fixing unit 60 but also to components that drive other rotating members in the copying machine 1.

The copying machine 1 according to the present embodiment is a color copying machine, but is not limited to this mode, and may be a monochrome copying machine.
In the copying machine 1 of the present embodiment, the toner image is transferred to the paper T via the intermediate transfer belt 48 (indirect transfer method). However, the present invention is not limited to this form, and is formed on the photosensitive drum. The transferred toner image may be directly transferred to the paper T (direct transfer method).
The copier 1 of the present embodiment is configured to print one side of the paper T, but is not limited to this, and may be configured to print both sides of the paper.

Further, the image forming apparatus of the present invention is not limited to the copying machine 1 described above. In other words, the image forming apparatus of the present invention may be a multi-function machine having a copy function, a facsimile function, a printer function, and a scanner function, or may be a facsimile or a printer.
The transfer material on which the toner image is fixed by the image forming apparatus of the present invention is not limited to the paper T, and may be a film sheet such as an OHP (overhead projector) sheet.

DESCRIPTION OF SYMBOLS 1 ... Copy machine (image forming apparatus) 60 ... Fixing part 61 ... Heating roller (rotating member), 62 ... Pressure roller (rotating member), 63 ... Motor (driving part), 64 ... Detection part, 90 ... Control 91: Drive control unit, 92 ... Determination unit, 93 ... First counting unit, 94 ... First determination unit, 95 ... Second counting unit, 96 ... Second determination unit

Claims (5)

A rotating member that rotates;
A drive unit that drives based on an input signal to rotate the rotating member and outputs an output signal based on the drive;
A drive control unit for controlling the drive unit based on supplying the input signal to the drive unit in order to change the rotation speed of the rotating member;
A determination unit that repeatedly determines whether or not there is a difference between the frequency of the input signal and the frequency of the output signal;
A first counter that increases a first count value by one when the determination unit determines that there is a difference between the frequency of the input signal and the frequency of the output signal;
A first determination unit that determines that the drive unit has failed when the first count value counted by the first counting unit exceeds a preset first abnormality determination value;
The first counting unit, when the rotation speed of the rotation member is changed based on the drive control unit controlling the drive unit, a first rotation speed that is a rotation speed after the change, When the absolute value of the difference from the second rotational speed that is the rotational speed before being changed exceeds a predetermined value, the first count value is returned to the initial value.
Image forming apparatus. The image forming apparatus according to claim 1, wherein the predetermined value is a rotation speed that is 4 to 8% of the second rotation speed. A detector that repeatedly detects rotation of the rotating member;
A second counter that increments the second count value by 1 when rotation of the rotating member is not detected by the detector;
And a second determination unit that determines that the rotating member is abnormal when the second count value counted by the second counter exceeds a preset second abnormality determination value. The image forming apparatus according to 1 or 2. The drive control unit is configured to perform the drive when the first determination unit determines that the drive unit is out of order, or when the second determination unit determines that the rotating member is abnormal. The image forming apparatus according to claim 3, wherein the driving of the unit is stopped. 5. The image forming apparatus according to claim 1, wherein the rotating member is a fixing roller disposed in a fixing unit that heats and pressurizes the transfer material and the toner to fix the toner to the transfer material. apparatus.

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