JP2018036308A - Cleaning device and image forming apparatus - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a cleaning device that can reduce a load acting on a cleaning mechanism in operation for switching between a forward path and a return path of a cleaning part, and an image forming apparatus.SOLUTION: A cleaning device 67 comprises: a moving mechanism 70 that moves a movable body 69 along a cleaning object from a position P1 to a position P2; a motor 71 that drives the moving mechanism 70; a current detection part 74 that detects a current flowing through the motor 71; a first detection processing part 841 that detects the movable body 69 reaching the position P2 when the current equal to or larger than a threshold is detected; a second detection processing part 842 that detects the movable body 69 reaching a position P3 between the position P1 and position P2 on the basis of the current detected by the current detection part 74; and a voltage control part 83 that, in a first period when the movable body 69 moves from the position P3 toward the position P2, applies, to the motor, a lower voltage as compared with that in a second period when the movable body 69 moves from the position P1 toward the position P3.SELECTED DRAWING: Figure 4

Description

  The present invention relates to a cleaning device and an image forming apparatus including the cleaning device.

  An image forming apparatus such as a printer may be provided with a cleaning device that automatically cleans a cleaning target such as a cover glass of an exposure device or a wire of a charging device. Specifically, this type of cleaning device cleans the object to be cleaned by reciprocating the cleaning part with the driving force transmitted from the motor while the cleaning part is in contact with the object to be cleaned. By the way, the forward path and the return path of the cleaning unit may be switched when an overcurrent due to the lock of the motor is detected when the cleaning unit contacts a stopper provided in the vicinity of the switching position ( For example, see Patent Documents 1 and 2).

JP 2009-139816 A JP 2013-238871 A

  However, in the configuration in which it is detected that the moving body has reached the switching position by intentionally locking the motor, a large load may act on a drive transmission member such as a gear included in the cleaning mechanism when the motor is locked. .

  An object of the present invention is to provide a cleaning device and an image forming apparatus that can reduce a load acting on a cleaning mechanism in a switching operation between a forward path and a return path of a cleaning unit.

  A cleaning device according to one aspect of the present invention includes a moving mechanism, a motor, a current detection unit, a contact unit, a first detection processing unit, a second detection processing unit, and a voltage control unit. The said moving mechanism moves the mobile body containing the cleaning part which contacts cleaning object from a 1st position to a 2nd position along the said cleaning object. The motor drives the moving mechanism. The current detection unit detects a current flowing through the motor. The contact portion contacts the moving body when the moving body reaches the second position and restricts the movement of the moving body. The first detection processing unit detects that the moving body has reached the second position when a current equal to or greater than a predetermined threshold is detected by the current detection unit during driving of the motor. The second detection processing unit detects that the moving body has reached a predetermined third position between the first position and the second position based on the current detected by the current detection unit. . In the first period in which the moving body moves from the third position to the second position, the voltage control unit sets a lower voltage than in the second period in which the moving body moves from the first position to the third position. Apply to the motor.

  An image forming apparatus according to another aspect of the present invention includes the cleaning device and an image forming unit that forms an image on a sheet.

  ADVANTAGE OF THE INVENTION According to this invention, the load which acts on a cleaning apparatus in the switching operation | movement of the outward path of a cleaning part and a return path | route can be reduced.

FIG. 1 is a cross-sectional view schematically showing a configuration of an image forming apparatus according to an embodiment of the present invention. FIG. 2 is a perspective view showing a state where the cleaning device is removed from the optical scanning device of the image forming apparatus shown in FIG. FIG. 3 is a perspective view showing an example of a cleaning device constituting the optical scanning device of the image forming apparatus shown in FIG. FIG. 4 is a block diagram showing the configuration of the cleaning device shown in FIG. FIG. 5 is a waveform diagram illustrating an example of a drive control signal (drive voltage) transmitted by the voltage control unit in the forward drive control process of the cleaning control process. FIG. 6 is a waveform diagram showing another example of the drive voltage applied to the motor in the forward drive control process. FIG. 7A is a waveform diagram showing another example of the drive voltage applied to the motor in the forward drive control process. FIG. 7B is a waveform diagram showing another example of the drive voltage applied to the motor in the forward drive control process. FIG. 7C is a waveform diagram showing another example of the drive voltage applied to the motor in the forward drive control process. FIG. 7D is a waveform diagram showing another example of the drive voltage applied to the motor in the forward drive control process. FIG. 8 is a waveform diagram showing an example of current detected by the current detection unit in the forward drive control process. FIG. 9 is a graph showing the environmental temperature dependence of the rotational speed and current value of the DC motor in relation to torque. FIG. 10 is a flowchart for explaining the cleaning control process. FIG. 11 is a flowchart showing the forward drive control process in the cleaning control process. FIG. 12 is a flowchart illustrating the return path drive control process in the cleaning control process. FIG. 13 is a flowchart illustrating another example of the return path drive control process.

  Hereinafter, embodiments of the present invention will be described with reference to the accompanying drawings for understanding of the present invention. In addition, the following embodiment is an example which actualized this invention, Comprising: The thing of the character which limits the technical scope of this invention is not.

[First Embodiment]
First, a schematic configuration of the image forming apparatus 10 according to the first embodiment of the present invention will be described.

[Schematic Configuration of Image Forming Apparatus 10]
As shown in FIG. 1, the image forming apparatus 10 includes an ADF 1, an image reading unit 2, an image forming unit 3, and the like. The image forming apparatus 10 is a multifunction machine having a print function, a fax function, a scan function, a copy function, and the like. Note that the present invention can also be applied to an image processing apparatus such as a facsimile, a scanner, or a copier.

  The ADF 1 is an automatic document conveying device that conveys a sheet placed as a document on the document setting unit by passing the sheet to a reading position of image data by the image reading unit 2. The image reading unit 2 can read an image from a sheet placed as an original on the contact glass or a sheet conveyed by the ADF 1. Specifically, the image reading unit 2 includes various optical system members such as a light source, a mirror, a lens, and a CCD.

  The image forming unit 3 includes a plurality of process units 4, an intermediate transfer belt 5, an optical scanning device 6, a secondary transfer roller 7, a fixing device 8, a paper discharge tray 9, a plurality of toner containers 11, a paper feed cassette 21, A conveyance path 22 and the like are provided. The image forming unit 3 forms a monochrome image or a color image on the sheet based on the input image data. The sheet is a sheet material such as paper, coated paper, postcard, envelope, and OHP sheet.

  Each of the process units 4 is an electrophotographic process unit including a photosensitive drum, a charging device, a developing device, a primary transfer roller, a static eliminator, and a cleaning device. Each of the process units 4 is arranged in parallel along the traveling direction of the intermediate transfer belt 5 and constitutes a so-called tandem image forming unit. Specifically, in each process unit 4, toner images corresponding to C (cyan), M (magenta), Y (yellow), and K (black) are formed.

  As shown in FIGS. 2 and 3, the optical scanning device 6 includes a removable cleaning device 67. FIG. 2 is a perspective view showing a state in which the removable cleaning device 67 is removed from the optical scanning device of the image forming apparatus 10.

  As shown in FIG. 2, the optical scanning device 6 includes a unit housing 60, a light source unit 61, a polygon mirror 62, and output mirrors 63 to 66. In the optical scanning device 6, laser light corresponding to each of the process units 4 is irradiated from the light source unit 61 and deflected and scanned in the main scanning directions D 1 and D 2 by the polygon mirror 62. The light scanned by the polygon mirror 62 is guided to each of the output mirrors 63 to 66 through optical members such as various lenses or mirrors. Laser light reflected by the output mirrors 63 to 66 is applied to the photosensitive drum of each process unit 4. The optical scanning device 6 is an example of an exposure apparatus of the present invention.

[Configuration of Cleaning Device 67]
As shown in FIGS. 3 and 4, the cleaning device 67 includes a cover unit 68, two moving bodies 69 </ b> A and 69 </ b> B, a moving mechanism 70, a motor 71, a temperature detection unit 72, a motor drive unit 73, a current detection unit 74, And a control unit 75.

  By the way, switching between the forward path and the return path of the two moving bodies 69A and 69B is to lock the motor 71 when the two moving bodies 69A and 69B come into contact with a contact portion 791 provided in the vicinity of a second position P2 described later. This may occur when an overcurrent is detected. However, in the configuration in which it is detected that the moving bodies 69A and 69B have reached the switching position by intentionally locking the motor 71, a large load is applied to a drive transmission member such as a gear included in the cleaning device 67 when the motor 71 is locked. May act. On the other hand, in the image forming apparatus 10 according to the present embodiment, it is possible to reduce the load acting on the cleaning device 67 in the switching operation between the forward path and the return path of the two moving bodies 69A and 69B.

  As shown in FIG. 3, the cover portion 68 constitutes the upper side of the optical scanning device 6 when the cleaning device 67 is attached to the optical scanning device 6. The cover 68 is provided with a plurality of emission windows 681 for emitting laser light emitted from the emission mirrors 63 to 66 of the optical scanning device 6. The exit window 681 is an example of a translucent member that is a cleaning target of the present invention.

  The moving body 69 cleans the exit window 681 by sliding in contact with the exit window 681 to be cleaned. Specifically, each moving body 69 has two cleaning portions 691 corresponding to the two exit windows 681. In the cleaning device 67, the two moving bodies 69 are reciprocated along the four exit windows 681 by the moving mechanism 70, whereby the four exit windows 681 are simultaneously cleaned by the cleaning unit 691 of each of the mobile bodies 69. The

  The moving mechanism 70 moves the moving body 69 including the cleaning unit 691 in contact with the emission window 681 from the first position P1 to the second position P2 or from the second position P2 to the first position P1 along the emission window 681. The moving mechanism 70 includes a wire 76, a drum 77, a plurality of pulleys 78, and four guide rails 79. Both ends of the wire 76 are connected to the drum 77, and are stretched by a plurality of pulleys 78 arranged on a path returning from the drum 77 and returning to the drum 77. Two moving bodies 69 are connected to the wire 76, and each moving body 69 reciprocates as the wire 76 reciprocates.

  The drum 77 of the moving mechanism 70 includes a first drum 81 and a second drum 82. The first drum 81 has a winding part 811, and the second drum 82 has a winding part 821. The first drum 81 and the second drum 82 are integrated and rotate in the same direction.

  Both ends of the wire 76 are connected to the first drum 81 and the second drum 82 so that the winding directions are opposite to each other. That is, when the first drum 81 and the second drum 82 rotate in the same direction, the wire 76 is pulled out from one of the first drum 81 and the second drum 82 and wound around the other.

  The first drum 81 is connected to the motor 71 via a drive transmission member including, for example, a drive gear (not shown) and a worm gear (not shown). The motor 71 can be driven forward and backward, and is constituted by, for example, a DC brush motor. In other words, the first drum 81 rotates forward and backward as the motor 71 is driven forward and backward. Since the second drum 82 is integrated with the first drum 81, the second drum 82 rotates in the same direction as the first drum 81 by the rotation of the first drum 81.

  The moving mechanism 70 configured in this way is driven by the first drum 81 being rotated clockwise or counterclockwise by the motor 71. When the first drum 81 rotates counterclockwise, the wire 76 is wound around the winding portion 811 of the first drum 81 and pulled out from the winding portion 821 of the second drum 82. Accordingly, the moving body 69A moves in the main scanning direction D1, and the moving body 69B moves in the main scanning direction D2. On the other hand, when the first drum 81 rotates clockwise, the wire 76 is drawn from the winding portion 811 of the first drum 81 and wound around the winding portion 821 of the second drum 82. Thereby, the moving body 69A moves in the main scanning direction D2, and the moving body 69B moves in the main scanning direction D1.

  Each of the four guide rails 79 extends along the main scanning directions D1 and D2. Each of the four guide rails 79 engages with the end of the moving body 69 and restricts the moving direction of the moving body 69 to the main scanning directions D1 and D2. Each of the four guide rails 79 has contact portions 791 at both ends. The contact portion 791 is provided at the end of the guide rail 79 in the main scanning directions D1 and D2. The contact portion 791 stops each of the moving bodies 69 at the first position P1 or the second position P2 when the end portions of the moving bodies 69 come into contact with each other to reciprocate the moving bodies 69.

  The temperature detector 72 measures the environmental temperature of the motor 71. The temperature detection result in the temperature detection unit 72 is transmitted as a temperature detection signal SGt to a detection processing unit 84 of the control unit 75 described later.

  The motor drive unit 73 drives the motor 71 based on the drive control signal SGm from the voltage control unit 83. The motor drive unit 73 is configured as a drive circuit including an input unit connected to a DC voltage, a switching element, and the like, for example.

  The current detection unit 74 and the current flowing through the motor 71 are detected. The current detection unit 74 detects a current flowing through the motor 71 at every minute constant time at least while the motor 71 is driven. That is, the current detection unit 74 monitors the current flowing through the motor 71 in real time. The detection current I detected by the current detection unit 74 is transmitted to the detection processing unit 84 of the control unit 75 as a current detection signal SGi at regular time intervals. Note that the current detection unit 74 may be incorporated in the motor drive unit 73.

  As shown in FIG. 4, the control unit 75 includes a voltage control unit 83 and a detection processing unit 84.

  The voltage control unit 83 controls the voltage applied to the motor 71 via the motor drive unit 73 by a drive control signal SGm transmitted to the motor drive unit 73. Specifically, the voltage control unit 83 controls forward drive, reverse drive, drive stop, and the like for the motor 71 based on a drive control signal SGm generated based on the detection result of the detection processing unit 84 and the like.

  In the present embodiment, the voltage control unit 83 performs the first drive period T1 (from the first position P1 to the third position P3) on the forward path from the first position P1 to the second position P2. Control corresponding to a lower voltage is applied to the motor 71 in the second drive period T2 (corresponding to the first period of the present invention) from the third position P3 to the second position P2.

  Next, the drive control signal SGm (that is, the drive voltage) transmitted from the voltage control unit 83 will be described with reference to FIG. FIG. 5 is a waveform example of the drive control signal SGm (drive voltage) when the motor 71 is PWM-controlled by the voltage control unit 83.

  As shown in FIG. 5, the voltage control unit 83 controls the voltage applied to the motor 71 and reduces the duty ratio in the second drive period T2 compared to the first drive period T1. As a result, the voltage applied to the motor 71 is smaller in the second drive period T2 than in the first drive period T1. Specifically, in the first drive period T1, the voltage control unit 83 continuously transmits an ON signal as the drive control signal SGm to the motor drive unit 73, thereby obtaining the first duty ratio Du1 in the first drive period T1. 100%. On the other hand, in the second drive period T2, the voltage control unit 83 switches the on signal and the off signal alternately as the drive control signal SGm at the same time interval and transmits the same to the motor drive unit 73, thereby the second duty ratio. Du2 is set to 50%. Thereby, the drive voltage for the motor 71 in the second drive period T2 is half of the drive voltage for the motor 71 in the first drive period T1. As described above, when the PWM control is employed, the voltage controller 83 drives the motor 71 in the second drive period T2 only by making the duty ratio in the second drive period T2 smaller than that in the first drive period T1. The voltage can be made lower than the drive voltage of the motor 71 in the first drive period T1. Further, by setting the duty ratio in the first drive period T1 to 100%, the motor 71 is driven in a substantially steady state in the first drive period T1. Therefore, variation in load during movement of the moving body 69 is suppressed, and the current detector 74 detects a stable current with little noise.

  However, the first duty ratio Du1 in the first driving period T1 may be such that the voltage controller 83 intermittently applies a voltage to the motor 71 as in the waveform example shown in FIG. In this case, the first duty ratio Du1 is considered to be within a range in which the variation in the load is as small as possible and a stable current can be detected by the current detection unit 74, for example, 70% or more, 80% or more, or 90%. .

  Further, the driving of the motor 71 in the first driving period T1 and the second driving period T2 does not need to be PWM control, and the voltage control unit 83 applies the voltage of the waveform example illustrated in FIGS. 7A to 7D to the motor 71. Thus, the driving voltage in the second driving period T2 may be lower than that in the first driving period T1. In the waveform example shown in FIG. 7A, the motor 71 is always driven at the first constant voltage V1 in the first driving period T1, and the motor 71 is driven at the second constant voltage V2 smaller than the first constant voltage V1 in the second driving period T2. Is always driven. In the waveform example shown in FIG. 7B, the drive voltage is decreased stepwise in order to set the motor 71 to the second constant voltage V2 smaller than the first constant voltage V1 in the second drive period T2. In the waveform example shown in FIG. 7C, the drive voltage is linearly reduced to set the motor 71 to the second constant voltage V2 smaller than the first constant voltage V1 in the second drive period T2. In the waveform example shown in FIG. 7D, the drive voltage is reduced in a curve in order to set the motor 71 to the second constant voltage V2 smaller than the first constant voltage V1 in the second drive period T2.

  Here, the third position P3 is a reference position where the voltage applied to the motor 71 is changed. The third position P3 is set to a position closer to the second position P2 than the first position P1 between the first position P1 and the second position P2. Specifically, the third position P3 has a ratio of the distance L1 between the first position P1 and the third position P3 and the distance L2 between the third position P3 and the second position P2 of 0.4: The position is set to 0: 6 to 0.1: 0.9.

  Thus, in the cleaning device 67, the third position P3 that defines the first drive period T1 and the second drive period T2 is set between the first position P1 and the second position P2, and the third position P3 is set. The reference position for changing the voltage applied to the motor 71 is used. In the cleaning device 67, the third position P3 is set to a position closer to the second position P2 than the first position P1, and the driving voltage in the second driving period T2 is set lower than that in the first driving period T1. ing. Therefore, when the moving body 69 reaches the second position P2 and the drive of the motor 71 is locked, the load acting on the cleaning device 67 is reduced. In particular, the load acting on the drive transmission member (not shown) that transmits the driving force of the motor 71 is reduced. As a result, the cleaning device 67 is prevented from being damaged by the drive transmission member, and the motor 71 having a relatively large output (torque) can be used.

  The detection processing unit 84 generates a lock detection signal SGr and a position detection signal SGp to be transmitted to the voltage control unit 83 based on the current detection signal SGi from the current detection unit 74 and the temperature detection signal SGt from the temperature detection unit 72. . In addition, as illustrated in FIG. 4, the detection processing unit 84 includes a first detection processing unit 841 and a second detection processing unit 842.

  The first detection processing unit 841 detects that the moving body 69 has reached the second position P2 based on the current detected by the current detection unit 74. Specifically, when the first detection processing unit 841 determines that the detection current I detected by the current detection unit 74 during driving of the motor 71 is equal to or greater than a predetermined lock detection threshold Ith. Then, it is detected that the moving body 69 has reached the second position P2. That is, the first detection processing unit 841 detects that the moving body 69 has reached the second position P2 by detecting an overcurrent (lock current) generated when the motor 71 is locked. In this case, the lock detection threshold Ith is set larger than the detection current I when the current detected by the current detection unit 74 is in a substantially steady state, and smaller than a mechanical breakage lock current Ide described later. In the present embodiment, the lock detection threshold Ith is set to a value selected from, for example, a range of 30% to 70% or a range of 40% to 60% of the mechanical breakage lock current Ide.

  As described above, in the cleaning device 67, the motor 71 having a relatively large output can be used by lowering the driving voltage in the second driving period T2. When the motor 71 having a large output is used, the setting range of the threshold value Ith for detecting the lock of the motor 71 is increased, and the setting of the threshold value Ith is facilitated. Further, if the motor 71 having a relatively large output can be used, it is possible to prevent the moving body 69 from being caught by the exit window 681 due to assembly tolerances when the mobile body 69 moves in contact with the exit window 681. . Thereby, in the 1st detection process part 841, the erroneous detection of the lock | rock of the motor 71 resulting from the catch of the moving body 69 can be suppressed.

  The second detection processing unit 842 detects that the moving body 69 has reached the third position P3 based on the current detected by the current detection unit 74. For example, the second detection processing unit 842 detects that the moving body 69 has reached the third position P3 by calculating the moving distance L of the moving body 69 based on the current detected by the current detection unit 74. The moving distance L of the moving body 69 is calculated based on, for example, the rotation speed N after calculating the rotation speed N based on the current detected by the current detection unit 74.

  Here, FIG. 8 is a waveform diagram showing an example of a current (current flowing in the motor 71) detected by the current detection unit 74. The waveform diagram shown in FIG. 8 is an example of the detected current I when the motor 71 is PWM-controlled by the drive control signal SGm (drive voltage) of the waveform example shown in FIG.

  As shown in FIG. 8, in the first drive period T1, the voltage control unit 83 continuously applies a positive voltage to the motor 71 that is stopped driving with the first duty ratio Du1 as 100% (see FIG. 5). . Therefore, the current detection unit 74 detects the peak current when the moving body 69 starts moving, and then detects the substantially steady current by moving the moving body 69 in a substantially steady state.

  On the other hand, in the second drive period T2, the voltage controller 83 continuously applies a positive voltage to the motor 71 with the second duty ratio Du2 being 50% (see FIG. 5). Therefore, the current detection unit 74 detects a substantially constant current until the movement of the moving body 69 is limited by the contact portion 791 of the guide rail 79. Thereafter, when the motor 71 is locked by the movement of the moving body 69 being restricted by the contact portion 791, the current detection portion 74 detects an overcurrent larger than the steady current. Here, when the application of the voltage to the motor 71 is interrupted, the current detected by the current detection unit 74 decreases rapidly.

  On the other hand, if a positive voltage is continuously applied to the motor 71 in a state where the drive of the motor 71 is locked, the overcurrent detected by the current detection unit 74 increases as shown by the phantom line in FIG. . As a result, when the load acting on the drive transmission member (not shown) of the cleaning device 67 exceeds the breakage limit of the drive transmission member, damage such as the gear constituting the drive transmission member flying may occur. is there. Such an overcurrent corresponding to a load when the drive transmission member is damaged is referred to as a mechanical breakage lock current Ide in this embodiment.

As shown in FIG. 9, in the DC motor, in the actual operating environment of the image forming apparatus 10, the drive current Is decreases as the environmental temperature increases, and the no-load rotation speed N ₀ increases. That is, the drive current Is flowing through the DC motor and the rotational speed N of the DC motor are affected by the environmental temperature of the motor 71. Therefore, in the image forming apparatus 10, the detection current I in the current detection unit 74 and the rotation speed N of the motor 71 calculated from the detection current I are affected by the environmental temperature of the motor 71. Therefore, the first detection processing unit 841 and the second detection processing unit 842 of the present embodiment perform temperature correction according to the environmental temperature of the motor 71, respectively, and perform lock detection of the motor 71 and position detection of the moving body 69.

  Specifically, the first detection processing unit 841 determines the lock detection threshold value Ith according to the environmental temperature of the motor 71 detected by the temperature detection unit 72. For example, the first detection processing unit 841 stores a plurality of threshold values in advance corresponding to a plurality of temperature ranges such as a room temperature, a high temperature, and a low temperature as the threshold Ith. And the 1st detection process part 841 determines the threshold value Ith according to the environmental temperature of the motor 71 from several threshold value Ith at the time of the start of the below-mentioned cleaning control process.

  The temperature correction of the threshold value Ith may be performed by multiplying the threshold value set for the reference environmental temperature (for example, the normal temperature threshold value Ith) by a correction coefficient corresponding to the environmental temperature of the motor 71. In addition, the temperature correction may be performed using a temperature correction formula that reflects the relationship between the environmental temperature and the threshold value Ith. In addition, instead of correcting the threshold value Ith with the temperature, the first detection processing unit 841 corrects the measured current with the environmental temperature, and compares the corrected value with the fixed threshold value Ith, thereby changing the environmental temperature. Lock detection in consideration may be performed.

  On the other hand, the second detection processing unit 842 can perform temperature correction on the detection current I detected by the current detection unit 74 or the rotation speed N calculated from this current according to the environmental temperature. As a method for correcting the temperature of the detection current I or the rotation speed N, a method of multiplying a correction coefficient, a method using a temperature correction formula, and the like can be adopted as in the temperature correction of the threshold value Ith. Further, in the second detection processing unit 842, instead of correcting the temperature of the detected current I value or the rotation speed N, the position calculated in consideration of the environmental temperature by correcting the movement distance calculated from the rotation speed N. Detection may be performed.

  As described above, the first detection processing unit 841 and the second detection processing unit 842 perform temperature correction so that the lock detection of the motor 71 can be detected even in an operating environment where the difference between the environmental temperature and the reference temperature (for example, normal temperature) is large. The position detection of the moving body 69 can be performed appropriately.

[Cleaning control processing]
Hereinafter, an example of the procedure of the cleaning control process executed by the control unit 75 will be described with reference to the flowcharts of FIGS.

<Step S1>
As shown in FIG. 10, in step S <b> 1, the control unit 75 determines whether there is a drive request for the motor 71 (step S <b> 1). When it is determined that there is a request for driving the motor 71 (step S1: Yes), the control unit 75 shifts the process to step S2. On the other hand, when the control unit 75 determines that there is no request for driving the motor 71 (step S1: No), the cleaning control process ends.

  In the image forming apparatus 10, the drive request is executed by the control unit 75, for example, every elapse of a predetermined period set in advance or every time a predetermined number of prints are transmitted. The drive request may be executed when the image forming apparatus 10 is turned on, for example, when the image forming apparatus 10 returns from the power saving mode. Further, the driving request may be executed when the photosensitive drum, the toner container 11 and the like of the image forming unit 3 are replaced.

<Step S2>
In step S2, the control unit 75 executes forward drive control processing for moving the moving body 69 from the first position P1 toward the second position P2 (step S2). When the forward drive control process is completed, the control unit 75 shifts the process to step S3. Details of the forward drive control process will be described later.

<Step S3>
In step S3, the control unit 75 performs a return path drive control process for moving the moving body 69 from the second position P2 toward the first position P1. When the return path drive control process ends, the control unit 75 ends the cleaning control process. Details of the return path drive control process will be described later.

[Outward drive control processing]
Next, an example of the procedure of the forward drive control process in step S2 executed by the control unit 75 will be described with reference to FIG.

<Step S21>
As shown in FIG. 11, in step S <b> 21, the control unit 75 detects the environmental temperature of the motor 71. The environmental temperature of the motor 71 is detected by the first detection processing unit 841 processing the temperature detection signal SGt transmitted from the temperature detection unit 72. When the control section 75 ends the process of step S21, the control section 75 shifts the process to step S22.

<Step S22>
In step S <b> 22, the detection processing unit 84 of the control unit 75 determines the lock detection threshold Ith according to the environmental temperature of the motor 71 detected by the current detection unit 74. As described above, this processing is performed by selecting, for example, the threshold value Ith corresponding to the environmental temperature of the motor 71 from a plurality of threshold values determined in advance corresponding to a plurality of temperature ranges in the detection processing unit 84. . When the process of step S22 ends, the control unit 75 shifts the process to step S23.

<Step S23>
In step S23, the second detection processing unit 842 of the control unit 75 determines a calculation formula for the rotation speed N. As described above, this processing is performed, for example, by selecting a calculation formula corresponding to the environmental temperature of the motor 71 from a plurality of calculation formulas determined in advance corresponding to a plurality of temperature ranges in the detection processing unit 84. Is called. When the control unit 75 finishes the process of step S23, the control unit 75 shifts the process to step S24.

<Step S24>
In step S24, the voltage control unit 83 of the control unit 75 drives the motor 71 to rotate forward at the first duty ratio Du1. The voltage control unit 83 continuously transmits the ON signal as the drive control signal SGm to the motor drive unit 73, thereby setting the first duty ratio Du1 to 100% (see FIG. 5).

  On the other hand, the motor drive unit 73 applies a drive voltage corresponding to the drive control signal SGm received from the voltage control unit 83 to the motor 71. Such a period in which the first duty ratio Du1 is set to 100% corresponds to the first drive period T1. In the first drive period T1, the motor 71 is driven in a steady state where a substantially constant positive voltage is applied (see FIG. 5). The moving body 69 starts moving when a voltage is applied to the motor 71. When the movement of the moving body 69 is started, the cleaning unit 691 held by the moving body 69 moves from the first position P1 to the second position P2 in a substantially steady state while being in contact with the emission window 681 to be cleaned. Move along the forward direction.

<Step S25>
In step S <b> 25, the second detection processing unit 842 of the control unit 75 calculates the moving distance L of the moving body 69. Specifically, the second detection processing unit 842 calculates the rotation speed N using the calculation formula determined in step S23 based on the current detected by the current detection unit 74, and then, based on the rotation speed N. The moving distance L of the moving body 69 is calculated.

<Step S26>
In step S <b> 26, the second detection processing unit 842 determines whether the moving distance L of the moving body 69 is equal to or greater than a predetermined set distance Lth. Here, the set distance Lth corresponds to the distance from the first position P1 to the third position P3. Therefore, the second detection processing unit 842 can detect whether the moving body 69 has reached the third position P3 by determining whether the moving distance L of the moving body 69 is equal to or greater than the set distance Lth in step S26.

  When the second detection processing unit 842 determines that the moving distance L of the moving body 69 is smaller than the set distance Lth (step S26: No), the second detecting processing unit 842 determines that the moving distance L of the moving body 69 is greater than or equal to the set distance Lth. (Step S26: Yes), the processes of steps S25 and S26 are repeated. On the other hand, when the second detection processing unit 842 determines that the moving distance L of the moving body 69 is greater than or equal to the set distance Lth (step S26: Yes), it determines that the moving body 69 has reached the third position P3. At this time, the second detection processing unit 842 transmits a position detection signal SGp indicating that the moving body 69 has reached the third position P3 to the voltage control unit 83.

  Note that the second detection processing unit 842 repeatedly performs the processes of steps S25 and S26 and determines that the moving distance L of the moving body 69 is smaller than the set distance Lth even after a predetermined time has elapsed (step S26: No) Assuming that some kind of error has occurred, a signal requesting to stop driving the motor 71 may be transmitted to the voltage controller 83.

<Step S27>
In step S27, the voltage control unit 83 of the control unit 75 changes the duty ratio from the first duty ratio Du1 to the second duty ratio Du2, and continues the forward rotation drive of the motor 71. Specifically, the voltage control unit 83 transmits the drive control signal SGm for switching the on signal and the off signal at regular intervals to the motor drive unit 73, thereby setting the second duty ratio Du2 to 50%. (See FIG. 5).

  On the other hand, the motor drive unit 73 applies a drive voltage corresponding to the drive control signal SGm received from the voltage control unit 83 to the motor 71. Thus, the period in which the second duty ratio Du2 is 50% corresponds to the second drive period T2. In the second drive period T2, the motor 71 is intermittently driven with the same level of amplitude (voltage) as in the first drive period T1 by alternately repeating a period in which a positive voltage is applied and a period in which no voltage is applied ( (See FIG. 5).

<Step S28>
In step S28, the first detection processing unit 841 of the control unit 75 determines whether or not the detection current I detected by the current detection unit 74 is equal to or greater than the lock detection threshold Ith determined in step S22. That is, the first detection processing unit 841 determines whether the overcurrent (lock current) of the motor 71 when the movement of the moving body 69 is restricted by the contact portion 791 of the guide rail 79 is equal to or greater than the threshold value Ith. Detects whether the second position P2 has been reached.

  When the first detection processing unit 841 determines that the detection current I in the current detection unit 74 is smaller than the lock detection threshold Ith (step S28: No), the detection current I is greater than or equal to the lock detection threshold Ith. The process of step S28 is repeated until it is determined that there is (step S28: Yes). On the other hand, when the first detection processing unit 841 determines that the detection current I is equal to or greater than the lock detection threshold Ith (step S28: Yes), the first detection processing unit 841 determines that the moving body 69 has reached the second position P2. At this time, the first detection processing unit 841 transmits a lock detection signal SGr indicating that the moving body 69 has reached the second position P2 to the voltage control unit 83.

  The first detection processing unit 841 repeats the process of step S28, and when it is determined that the detection current I is smaller than the lock detection threshold Ith even after a predetermined time has elapsed (step S28: No). Assuming that some kind of error has occurred, a signal requesting to stop driving the motor 71 may be transmitted to the voltage control unit 83.

<Step S29>
In step S <b> 29, when the voltage control unit 83 receives the position detection signal SGp indicating that the moving body 69 has reached the second position P <b> 2, the voltage control unit 83 sends a drive control signal SGm for stopping the driving of the motor 71 to the motor driving unit 73. Send. That is, the voltage control unit 83 causes the motor driving unit 73 to stop driving the motor 71. When the process of step S29 ends, the control unit 75 ends the forward drive control process and shifts the process to step S3 (return drive control process) in FIG.

[Return drive control processing]
Next, an example of the procedure of the return path drive control process in step S3 executed by the control unit 75 will be described with reference to FIG.

<Step S31>
As shown in FIG. 12, in step S31, the voltage control unit 83 of the control unit 75 drives the motor 71 in the reverse direction with the third duty ratio Du3. Specifically, the voltage control unit 83 continuously transmits an ON signal as the drive control signal SGm and transmits it to the motor drive unit 73, thereby setting the third duty ratio Du3 in the same manner as in the case of the first duty ratio Du1. 100% (see FIG. 5).

  On the other hand, the voltage control unit 83 applies a negative voltage to the motor 71 by transmitting a drive control signal SGm to the motor drive unit 73, thereby driving the motor 71 in the reverse direction. The moving body 69 starts to move along the return path direction from the second position P2 to the first position P1 when the motor 71 is driven in reverse.

<Step S32>
In step S <b> 32, the voltage control unit 83 of the control unit 75 determines whether a predetermined time has elapsed since the motor 71 was driven in the reverse direction. When it is determined that the predetermined time has not elapsed (step S32: No), the voltage control unit 83 repeatedly performs the determination in step S32 until it is determined that the predetermined time has elapsed (step S32: Yes). On the other hand, when the voltage control unit 83 determines that the predetermined time has elapsed (step S32: Yes), the voltage control unit 83 transmits a drive control signal (off signal) for stopping the drive of the motor 71 to the motor drive unit 73. Note that the control unit 75 may cause the position detection unit 162 to determine whether or not the predetermined time has elapsed.

<Step S33>
In step S <b> 33, the voltage control unit 83 transmits an off signal to the motor driving unit 73 to stop the application of voltage to the motor 71 and ends the cleaning control process.

[Second Embodiment]
In the first embodiment, as an example of the return drive control process of the cleaning control process, the driving of the motor 71 is stopped after a lapse of a predetermined time. However, the return drive control process has the same procedure as the forward drive control process. May be executed. Here, referring to FIG. 13, the return path drive control process as the second embodiment will be described.

<Step S301>
As shown in FIG. 13, in step S301, the voltage control unit 83 of the control unit 75 drives the motor 71 in the reverse direction with the fourth duty ratio Du4. As in the case of the above-described forward drive control process, the voltage control unit 83 continuously transmits the ON signal as the drive control signal SGm to the motor drive unit 73, thereby setting the fourth duty ratio Du4 to 100%.

  On the other hand, the motor drive unit 73 applies a negative voltage corresponding to the drive control signal SGm received from the voltage control unit 83 to the motor 71. Thereby, the moving body 69 starts moving when a voltage is applied to the motor 71. When the movement of the moving body 69 is started, the cleaning unit 691 held by the moving body 69 moves from the second position P2 to the first position P1 in a substantially steady state while being in contact with the emission window 681 to be cleaned. Move along the return direction.

<Step S302>
In step S <b> 302, the second detection processing unit 842 of the control unit 75 calculates the moving distance L of the moving body 69. Specifically, the second detection processing unit 842 calculates the rotation speed N using the calculation formula determined in step S23 of FIG. 11 based on the current detected by the current detection unit 74, and then the rotation speed N The moving distance L of the moving body 69 is calculated based on the above.

<Step S303>
In step S303, the second detection processing unit 842 determines whether the moving distance L of the moving body 69 is greater than or equal to a predetermined set distance Lth. Here, the set distance Lth corresponds to the distance from the second position P2 to the fourth position P4 (see FIG. 4). Therefore, the second detection processing unit 842 can determine whether or not the moving body 69 has reached the fourth position P4 by determining whether or not the moving distance L of the moving body 69 is greater than or equal to the set distance Lth in step S303. Note that a period until the moving body 69 moves from the second position P2 to the fourth position P4 (a period in which the fourth duty ratio Du4 is 100%) corresponds to a fourth period of the present invention.

  When the second detection processing unit 842 determines that the moving distance L of the moving body 69 is smaller than the set distance Lth (step S303: No), the second detecting processing unit 842 determines that the moving distance L of the moving body 69 is greater than or equal to the set distance Lth. Until (step S303: Yes), the processes of steps S302 and S303 are repeated. On the other hand, when the second detection processing unit 842 determines that the moving distance L of the moving body 69 is greater than or equal to the set distance Lth (step S303: Yes), it determines that the moving body 69 has reached the fourth position P4. At this time, the second detection processing unit 842 transmits a position detection signal SGp indicating that the moving body 69 has reached the fourth position P4 to the voltage control unit 83.

<Step S304>
In step S304, the voltage control unit 83 of the control unit 75 changes the duty ratio from the fourth duty ratio Du4 to the fifth duty ratio Du5, and continues the reverse drive of the motor 71. Specifically, the voltage control unit 83 of the control unit 75 transmits the drive control signal SGm for switching the ON signal and the OFF signal at regular intervals to the motor drive unit 73, thereby setting the fifth duty ratio Du5, for example. 50%.

  On the other hand, the motor drive unit 73 applies a negative voltage corresponding to the drive control signal SGm received from the voltage control unit 83 to the motor 71. Thus, in the period in which the fifth duty ratio Du5 is 50%, the period in which the voltage is applied to the motor 71 and the period in which the voltage is not applied are alternately repeated, and the voltage is applied to the motor 71 at the fourth duty ratio Du4. Intermittent drive with the same level of amplitude (voltage) as Therefore, in the period in which the fifth duty ratio Du5 is 50%, the voltage applied to the motor 71 is smaller than in the period in which the fourth duty ratio Du4 is 100%.

<Step S305>
In step S305, the first detection processing unit 841 of the control unit 75 determines whether or not the detection current I detected by the current detection unit 74 is equal to or greater than the lock detection threshold Ith determined in step S22 of FIG. That is, the first detection processing unit 841 determines whether the overcurrent (lock current) of the motor 71 when the movement of the moving body 69 is restricted by the contact portion 791 of the guide rail 79 is equal to or greater than the threshold value Ith. Detects whether the first position P1 has been reached. Note that a period until the moving body 69 moves from the fourth position P4 to the first position P1 (a period in which the fifth duty ratio Du5 is 50%) corresponds to the third period of the present invention.

  When the first detection processing unit 841 determines that the detection current I in the current detection unit 74 is smaller than the lock detection threshold Ith (step S305: No), the detection current I is equal to or greater than the lock detection threshold Ith. The process of step S305 is repeated until it is determined that there is (step S305: Yes). On the other hand, when the first detection processing unit 841 determines that the detected current I is equal to or greater than the lock detection threshold Ith (step S305: Yes), the first detection processing unit 841 determines that the moving body 69 has reached the first position P1. At this time, the first detection processing unit 841 transmits a lock detection signal SGr indicating that the moving body 69 has reached the first position P1 to the voltage control unit 83.

<Step S306>
In step S306, when the voltage control unit 83 of the control unit 75 receives the lock detection signal SGr, the voltage control unit 83 stops applying the voltage to the motor 71 and ends the cleaning control process.

  By the way, in the said 1st Embodiment and the said 2nd Embodiment, although the case where cleaning object was the output window 681 of the optical scanning device 6 was mentioned as an example, it demonstrated, Embodiment of this invention is not restricted to this. For example, the cleaning device of the present invention can be applied to cleaning various wires. Examples of the various wires include a charging device wire.

DESCRIPTION OF SYMBOLS 10 Image forming apparatus 6 Optical scanning device 67 Cleaning apparatus 681 Output window 69 Moving body 691 Cleaning part 70 Moving mechanism 71 Motor 72 Temperature detection part 73 Motor drive part 74 Current detection part 75 Control part 791 Contact part 83 Voltage control part 841 1st Detection processing unit 842 Second detection processing unit P1 First position P2 Second position P3 Third position P4 Fourth position T1 First drive period T2 Second drive period

Claims (9)

A moving mechanism that moves a moving body including a cleaning unit that comes into contact with the cleaning target from the first position to the second position along the cleaning target;
A motor for driving the moving mechanism;
A current detection unit for detecting a current flowing in the motor;
A contact portion that contacts the moving body when the moving body reaches the second position and restricts the movement of the moving body;
A first detection processing unit for detecting that the moving body has reached the second position when a current equal to or greater than a predetermined threshold is detected by the current detection unit during driving of the motor;
A second detection processing unit configured to detect that the moving body has reached a predetermined third position between the first position and the second position based on a current detected by the current detection unit;
The voltage during which the moving body applies a lower voltage to the motor in the first period from the third position to the second position than in the second period in which the moving body moves from the first position to the third position. A control unit;
A cleaning device comprising: The voltage control unit controls a voltage applied to the motor by PWM control, and makes a duty ratio of the PWM control in the first period smaller than a duty ratio of the PWM control in the second period.
The cleaning device according to claim 1. The voltage control unit sets the duty ratio of the second period to 100%;
The cleaning device according to claim 2. The second detection processing unit calculates the rotational speed of the motor based on the current detected by the current detection unit, and determines the position of the moving body based on the rotational speed.
The cleaning device according to claim 1. A temperature detector for detecting the environmental temperature of the motor;
The second detection processing unit calculates the rotation speed of the motor according to the current detected by the current detection unit and the temperature detected by the temperature detection unit,
The cleaning device according to claim 4. A temperature detector for detecting the environmental temperature of the motor;
The first detection processing unit determines the threshold according to a temperature detected by the temperature detection unit;
The cleaning device according to claim 1. The second detection processing unit further detects that the moving body has reached a predetermined fourth position between the second position and the first position based on the current detected by the current detection unit. Is possible,
When the motor and the moving mechanism reciprocate the moving body between the first position and the second position, the voltage control unit moves the moving body from the fourth position to the first position. In the third period, the moving body applies a lower voltage to the motor than in the fourth period in which the moving body moves from the second position to the fourth position.
The cleaning device according to claim 1. The cleaning object is a translucent member arranged in a light emission region of an exposure apparatus in the image forming apparatus.
The cleaning device according to claim 1. The cleaning device according to claim 1, an image forming unit that forms an image on a sheet,
An image forming apparatus comprising:

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