JP2008134305A - Image forming apparatus and discharge electrode cleaning device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide the technology of reducing load applied to a wire electrode or the wound wire of a motor during the cleaning of the wire electrode. <P>SOLUTION: The motor 209 outputs drive force for moving a cleaning member 200. Elastic members Gi and Hj are disposed on the path of the reciprocating movement of the cleaning member 200, and apply load to the cleaning member 200 passing them. The direction of the load is opposite to the moving direction of the cleaning member 200 and the degree of the load does not cause full lock of the motor 209. A motor current monitoring section 301 monitors a motor current supplied to the motor 209 from a power source 300. When the cleaning member 200 passes the positions of the elastic members Gi and Hj, the motor current increases due to the load applied in the direction opposite to the moving direction. Based on the result of monitoring the motor current by the motor current monitoring section 301, a position specifying section 302 specifies the position of the cleaning member 200 on the path of the reciprocating movement. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a discharge electrode cleaning device for cleaning a wire electrode of a corona discharger, or an electrophotographic image forming apparatus including the discharge electrode cleaning device.

  An electrophotographic image forming apparatus forms an image on a recording material by the following process: charging a photosensitive drum; forming an electrostatic latent image on the photosensitive drum with writing light (laser light); A toner is attached to the electrostatic latent image on the photosensitive drum and developed to form a visible image; the visible image toner is transferred from the photosensitive drum to a recording material (recording paper); The recording material is output by being fixed on the recording material with heat or pressure; the toner or residual charge remaining on the photosensitive drum is removed by a cleaner or a static eliminator to prepare for the next image forming process.

  In such a process, a corona discharger is widely used in a charging process of a photosensitive drum, a toner transfer process, a residual charge removal process, and the like. A corona discharger may also be used in the process of separating the recording material from the photosensitive drum.

  The corona discharger includes a wire made of tungsten or stainless steel as a discharge electrode in a hollow region of a shield member whose longitudinal direction is the axial direction of the rotary drum. The discharge electrode (wire electrode) is stretched in a state where both ends thereof are supported by an insulating member. During use, a high voltage is applied to the wire electrode to cause corona discharge, and the generated charge adheres to the surface of the photosensitive drum, and the toner on the photosensitive drum is electrostatically attracted by the charge. A transfer process, a charge removal process, and a separation process are performed.

  The wire electrode of a corona discharger causes toner or dust to adhere to it during repeated use, resulting in a reduction in image quality due to a decrease in discharge effect and uneven discharge. Therefore, conventionally, the corona discharger has been manually removed and the discharge wire has been wiped off with a cloth or the like. In recent years, an image forming apparatus including a cleaning device that cleans a wire electrode every time a predetermined number of image forming processes are performed is also widely used.

  As a discharge electrode cleaning device, a device that reciprocates along a wire electrode while a cleaning member is in contact with the wire electrode is known. In order to enhance the cleaning effect of such a discharge electrode cleaning device, it is necessary to ensure that the cleaning member reciprocates. Therefore, conventionally, a method of detecting the position of the cleaning member by providing a microswitch or a microsensor at the end of the wire (standby position (position where the cleaning member is removed from the wire electrode), reverse position) has been used. .

  However, this method has been pointed out as a problem that a space for installing a microswitch or the like is required. In particular, an image forming apparatus such as a color printer capable of color output is provided with four sets of image forming components such as a photosensitive drum and the space in the housing is narrow. It was difficult to apply).

  In view of such a problem, a method of utilizing a lock current of a motor that drives the cleaning member (an overcurrent that flows when the cleaning member reaches the end of the wire electrode and the motor locks) has been developed. For example, the discharge electrode cleaning device disclosed in Patent Document 1 calculates a lock level based on the average value of the motor current of a motor that drives the cleaning member, and the cleaning member moves forward or backward when the motor current exceeds the lock level. The motor is configured to reverse or stop as if it reached the end position.

Japanese Patent Laid-Open No. 6-149021

  However, in the conventional method using the lock current, the cleaning member reaches the end of the wire electrode and is fully locked (that is, the motor is energized with the cleaning member stopped). Because current is used, every time the position of the cleaning member is detected, a large force is applied to the wire electrode (the force applied to the wire electrode as the cleaning member moves), which places a heavy burden on the wire electrode. Become. Therefore, when this conventional method is applied, there is a problem that it is necessary to enlarge the corona discharger in order to increase the strength of the wire electrode. This is a particularly serious problem in an image forming apparatus capable of color output with a small empty space in the housing.

  In addition, in this conventional method, a very large current is applied to the fully locked motor winding, so a very large load is applied to the winding of the motor, and the life of the motor is shortened. There was also a problem that the deterioration of the motor with time progressed quickly.

  Moreover, when returning from the power-off state during the cleaning of the wire electrode, it is necessary to return the cleaning member to the standby position. However, in the conventional discharge electrode cleaning device, there is a possibility that a lock current is generated at a position other than the standby position due to distortion or contamination of the wire electrode, and the standby position is erroneously detected. If it does so, an electric current will be sent through the wire electrode in the state which the cleaning member contacted, and there existed a possibility that a discharge effect might fall, discharge nonuniformity might arise, or an electric current might leak from a corona discharger.

  The present invention has been made to solve the above-described problems, and an image forming apparatus and a discharge electrode cleaning capable of reducing a load applied to a wire electrode or a winding of a motor at the time of cleaning the wire electrode. An object is to provide an apparatus.

  Another object of the present invention is to provide an image forming apparatus and a discharge electrode cleaning apparatus capable of reliably guiding a cleaning member for cleaning a wire electrode to a standby position.

  In order to achieve the above object, the invention according to claim 1 is directed to a wire electrode that generates an electric charge upon application of a voltage, a cleaning member that is in contact with the wire electrode, and the cleaning member as the wire electrode. An image forming apparatus that forms an image on a recording material by using electric charges generated from the wire electrode, and is provided on the reciprocating movement trajectory. Load applying means for applying a load to the cleaning member in a direction opposite to the moving direction when the cleaning member moved by the means passes, and monitoring means for monitoring a current supplied to the drive means And a specifying means for specifying a position of the cleaning member on the track based on a monitoring result of the current by the monitoring means.

  According to a second aspect of the present invention, in the image forming apparatus according to the first aspect of the present invention, the specifying unit is configured based on a moving result of the cleaning member by the driving unit together with a monitoring result of the current. The position of the cleaning member is specified.

  The invention according to claim 3 is the image forming apparatus according to claim 1 or 2, wherein a plurality of the load applying units are arranged on the trajectory at predetermined intervals. It is arranged, and the specifying means specifies the position of the cleaning member on the track by comparing the current waveform as the monitoring result with the interval.

  According to a fourth aspect of the invention, there is provided the image forming apparatus according to the first or second aspect, wherein a plurality of the load applying units are provided on the track by a preset load amount. The load is applied to the cleaning member, and the specifying unit compares the load waveform with the waveform of the current as the monitoring result to determine whether the cleaning member is on the track. The position of is specified.

  The invention according to claim 5 is the image forming apparatus according to claim 3 or 4, wherein at least one of the plurality of load applying means is in the vicinity of a start position of the reciprocating movement. Provided, and the specifying means specifies at least that the position of the cleaning member is the start position.

  The invention according to claim 6 is the image forming apparatus according to claim 3 or 4, wherein at least one of the plurality of load applying means is in the vicinity of a reversal position in the reciprocating movement. The specifying means specifies at least that the position of the cleaning member is the reverse position.

  The invention according to claim 7 is the image forming apparatus according to claim 3 or 4, wherein at least one of the plurality of load applying means is in the vicinity of a start position of the reciprocating movement. At least one of the remaining load applying means is provided in the vicinity of the reversal position in the reciprocating movement, and the specifying means is configured to detect that the cleaning member is located at the start position and the reversal. It is characterized by identifying and specifying being located at a position.

  The invention according to claim 8 is the image forming apparatus according to any one of claims 1 to 7, wherein the cleaning is controlled along the reciprocating orbit by controlling the driving means. Control means for moving the member by a predetermined distance, the specifying means measures a movement time when the member is moved by the predetermined distance, and based on the measured current time, based on the monitoring result of the current The specified position of the cleaning member is corrected.

  The invention according to claim 9 is the image forming apparatus according to any one of claims 1 to 7, wherein the driving is performed based on the position of the cleaning member specified by the specifying unit. Control means for controlling the means to stop the movement of the cleaning member or reverse the moving direction of the cleaning member is further provided.

  The invention according to claim 10 is the image forming apparatus according to any one of claims 1 to 7, wherein the driving is performed based on the position of the cleaning member specified by the specifying unit. Control means for controlling the means to move the cleaning member to the starting position of the reciprocating movement is further provided.

  The invention according to claim 11 is the image forming apparatus according to any one of claims 1 to 10, wherein the load applying unit is arranged on the cleaning member moved by the driving unit. It includes a load applying member provided to contact and apply the load.

  According to a twelfth aspect of the present invention, in the image forming apparatus according to the eleventh aspect, the load applying member is an elastic member that is deformed when being in contact with the cleaning member. And

  According to a thirteenth aspect of the present invention, in the image forming apparatus according to the twelfth aspect, the elastic member is a leaf spring.

  According to a fourteenth aspect of the present invention, in the image forming apparatus according to the twelfth aspect, the elastic member has flexibility.

  The invention according to claim 15 is the image forming apparatus according to any one of claims 11 to 14, wherein the wire electrode constitutes a corona discharger and is provided in a shield member. The cleaning member is disposed in the shield member and is in contact with the wire electrode; and a holding portion that holds the pad at one end and the other end is disposed outside the shield member; The load applying means is disposed outside the shield member and contacts the holding portion of the cleaning member.

  According to a sixteenth aspect of the present invention, there is provided a cleaning member that is brought into contact with a wire electrode that generates an electric charge upon application of a voltage, a driving unit that reciprocates the cleaning member along the wire electrode, and the reciprocation. A load applying means for applying a load to the cleaning member in a direction opposite to the moving direction when the cleaning member that is provided on the movement track and is moved by the driving means passes; Discharging electrode cleaning comprising: monitoring means for monitoring a current to be energized; and specifying means for specifying a position of the cleaning member on the track based on a monitoring result of the current by the monitoring means. Device.

  Further, the invention according to claim 17 is the discharge electrode cleaning device according to claim 16, wherein the specifying means is based on a moving direction of the cleaning member by the driving means together with a monitoring result of the current. The position of the cleaning member is specified.

  The invention according to claim 18 is the discharge electrode cleaning device according to claim 16 or claim 17, wherein a plurality of the load applying means are arranged on the track at predetermined intervals. The identifying means compares the waveform of the current as the monitoring result with the interval, and identifies the position of the cleaning member on the track.

  The invention according to claim 19 is the discharge electrode cleaning device according to claim 16 or claim 17, wherein a plurality of load applying means are provided only on a preset load amount on the track. It arrange | positions so that the said load may be provided with respect to the said cleaning member, The said specific means compares the said current waveform as the said monitoring result, and the increase amount of the said driving force, The said cleaning member The position on the orbit is specified.

  The invention according to claim 20 is the discharge electrode cleaning device according to claim 18 or 19, wherein at least one of the plurality of load applying means is provided at a start position of the reciprocating movement. Provided in the vicinity, the specifying means specifies at least that the position of the cleaning member is the start position.

  The invention according to claim 21 is the discharge electrode cleaning device according to claim 18 or claim 19, wherein at least one of the plurality of load applying means has a reverse position in the reciprocating movement. Provided in the vicinity, the specifying means specifies at least that the position of the cleaning member is the reverse position.

  The invention according to claim 22 is the discharge electrode cleaning device according to claim 18 or 19, wherein at least one of the plurality of load applying means is provided at a start position of the reciprocating movement. At least one of the remaining load applying means is provided in the vicinity of the reversal position in the reciprocating movement, and the specifying means includes the cleaning member being located at the start position and It is characterized by identifying and specifying that it is located at the reverse position.

  The invention according to claim 23 is the discharge electrode cleaning device according to any one of claims 16 to 22, wherein the drive means is controlled to follow the reciprocating trajectory. A control unit configured to move the cleaning member by a predetermined distance; the specifying unit measures a movement time when the cleaning member is moved by the predetermined distance; and based on the current monitoring result based on the measured movement time. The position of the specified cleaning member is corrected.

  Moreover, invention of Claim 24 is the discharge electrode cleaning apparatus as described in any one of Claims 16-22, Comprising: Based on the position of the said cleaning member specified by the said specification means, It further comprises control means for controlling the driving means to stop the movement of the cleaning member or reverse the moving direction of the cleaning member.

  Moreover, invention of Claim 25 is the discharge electrode cleaning apparatus as described in any one of Claims 16-22, Comprising: Based on the position of the said cleaning member specified by the said specific means, Control means for controlling the driving means to move the cleaning member to the start position of the reciprocating movement is further provided.

  The invention according to claim 26 is the discharge electrode cleaning device according to any one of claims 16 to 25, wherein the load applying means is moved by the driving means. And a load applying member provided to apply the load in contact with the battery.

  The invention according to claim 27 is the discharge electrode cleaning device according to claim 26, wherein the load applying member is an elastic member that is deformed when contacting the cleaning member. Features.

  The invention according to claim 28 is the discharge electrode cleaning device according to claim 27, wherein the elastic member is a leaf spring.

  The invention according to claim 29 is the discharge electrode cleaning device according to claim 27, wherein the elastic member is a flexible member.

  Further, the invention according to claim 30 is the discharge electrode cleaning device according to any one of claims 26 to 29, wherein the wire electrode constitutes a corona discharger and is disposed in the shield member. The cleaning member is disposed within the shield member and is in contact with the wire electrode; and a holding portion that holds the pad at one end and the other end is disposed outside the shield member. The load applying means is disposed outside the shield member and contacts the holding portion of the cleaning member.

  The present invention provides a cleaning member that is in contact with a wire electrode, a drive unit that reciprocates the cleaning member along the wire electrode, and a direction opposite to the moving direction with respect to the cleaning member that is provided on the reciprocating track. A load applying means for applying a load to the driving means, a monitoring means for monitoring the current supplied to the driving means, and a specifying means for specifying the position of the cleaning member on the track based on the monitoring result of the current by the monitoring means. ing.

  The load applying means applies a load that allows the cleaning member to pass as described above. Therefore, when the cleaning member passes the position of the load applying means, the driving means is not fully locked. Further, according to the present invention, it is possible to monitor a change in current to the driving unit due to the load applied to the cleaning member by the load applying unit, and specify the position of the cleaning member based on the monitoring result.

  Thus, according to the present invention, the position of the cleaning member can be specified and the wire electrode can be cleaned (that is, the cleaning member can be reciprocated) while avoiding the full lock of the drive means. It is possible to reduce the burden on (in particular, the winding of the motor).

  Further, according to the present invention, the position of the cleaning member is specified based on the result of monitoring the change in the current to the driving means caused by the load applied to the cleaning device by the load applying means, and the specified position Since the driving means can be controlled based on the above and the cleaning member can be moved to the start position of the reciprocating movement, the cleaning member can be reliably guided to the start position (standby position).

  Specific examples of preferred embodiments of an image forming apparatus and a discharge electrode cleaning apparatus according to the present invention will be described in detail with reference to the drawings.

[Image forming apparatus]
Examples of the image forming apparatus according to the present invention include an electrophotographic printer, a copying machine, and a facsimile. In the present embodiment, an image forming apparatus (color composite machine) that combines a printer capable of color output, a copier, and the like will be described.

[Constitution]
An example of the configuration of the image forming apparatus according to the present invention is shown in FIG. The image forming apparatus 10 shown in FIG. 1 includes an automatic document feeder 20, a reading unit 30, and a printer unit 40.

  The automatic document feeder 20 has a function of feeding the originals 2 stacked on the original placement tray 21 one by one to the reading portion of the reading unit 30 and discharging the read originals to the paper discharge tray 27. When the document 2 is a double-sided document, the automatic document feeder 20 has a function of reversing the front and back of the document 2 and feeding it again to the reading unit 30 after one side is read.

  The automatic document feeder 20 passes the document 2 in close contact with a paper feed roller 22 that sequentially feeds the document 2 loaded on the document loading tray 21 from the top and a contact glass 31 that is a reading position of the document 2. And a guide roller 24 for guiding the document 2 fed by the paper feed roller 22 along the contact roller 23. Further, a switching claw 25 for switching the advancing direction of the document 2 that has passed through the contact glass 31, a reversing roller 26 for reversing the front and back of the double-sided document, a paper discharge tray 27 for discharging the document 2 that has been read, and the like. Have.

  The reading unit 30 has a function of reading the document 2 in color. More specifically, the reading unit 30 optically reads the original 2 into three colors of red (R), green (G), and blue (B), and reads the read data as yellow (Y) and magenta. The image data is converted into density data of four colors (M), cyan (C), and black (K), and these four color image data are output.

  The reading unit 30 includes an exposure scanning unit 35 including a light source 33 and a mirror 34, a color line image sensor 36 that receives reflected light from the document 2 and outputs an electrical signal corresponding to the light intensity, and A condensing lens 37 that condenses the reflected light from the document onto the line image sensor 36, and various mirrors 38 that form an optical path for guiding the reflected light from the mirror 34 of the exposure scanning unit 35 to the line image sensor 36; It has.

  When reading the document 2 fed by the automatic document feeder 20, the exposure scanning unit 35 moves to the reading position below the contact glass 31 and stops, and the document 2 conveyed by the contact roller 23 thereon is stopped. It is supposed to read. When reading the document 2 placed on the platen glass 32, the exposure scanning unit 35 moves from the left to the right along the lower surface of the platen glass 32 so as to read the stationary document.

  The printer unit 40 is a tandem color printer using an electrophotographic system. The printer unit 40 includes an endless belt-shaped intermediate transfer belt 41 and a plurality of image forming units 50Y, 50M, 50C, and 50K that respectively form single color (Y, M, C, and K) images on the intermediate transfer belt 41. A paper feeding unit 70 that feeds the transfer paper, a transport unit 80 that transports the fed transfer paper, and a fixing device 42.

  The image forming unit 50 </ b> Y forms a yellow (Y) image on the intermediate transfer belt 41. The image forming unit 50M forms a magenta (M) color image on the intermediate transfer belt 41. The image forming unit 50 </ b> C forms a cyan (C) image on the intermediate transfer belt 41. The image forming unit 50 </ b> K forms a black (K) image on the intermediate transfer belt 41.

  The image forming unit 50Y includes a cylindrical photosensitive drum 51Y on which an electrostatic latent image is formed, a charging device 52Y disposed around the image forming unit 51Y, a developing device 53Y, and a cleaning device 54Y. Further, a laser diode, a polygon mirror, and a laser unit 55Y including various lenses and mirrors are provided.

  The photosensitive drum 51Y is driven by a drive unit (not shown) and rotates in a certain direction (the direction of arrow A in the figure). The charging device 52Y uniformly charges the photosensitive drum 51Y. The laser unit 55Y forms an electrostatic latent image on the photosensitive drum 51Y by irradiating the photosensitive drum 51Y with laser light that is turned on and off according to yellow image data. The developing device 50Y visualizes the electrostatic latent image with yellow toner. This toner image is transferred to the intermediate transfer belt 41 at a location where it contacts the intermediate transfer belt 41. The cleaning device 54Y removes and collects the toner remaining on the surface of the photosensitive drum 51Y after the transfer by rubbing with a blade or the like.

  The image forming units 50M, 50C, and 50K have the same configuration as that of the image forming unit 50Y except that toner colors are different and laser light is turned on / off with image data corresponding to each color. Corresponding components are denoted by reference numerals having the same numerical part and different subscripts (M, C, K instead of Y).

  The intermediate transfer belt 41 is rotatably supported by winding a plurality of rollers. The intermediate transfer belt 41 is rotated in a direction indicated by an arrow B by a driving unit (not shown). In the process of going around, color images are formed on the intermediate transfer belt 41 in the order of (Y), (M), (C), and (K) by the image forming units 50Y, 50M, 50C, and 50K. Is synthesized. This color image is transferred from the intermediate transfer belt 41 to the recording paper (recording material) at the secondary transfer location D provided at the lower end of the circulation path of the intermediate transfer belt 41. The toner remaining on the intermediate transfer belt 41 after the transfer is removed by the cleaning device 44.

  The paper supply unit 70 has a plurality of paper supply cassettes 71 and normally stores recording papers of different sizes and types. Near the outlet of each paper feed cassette 71, a first paper feed roller 72 is provided that feeds the uppermost recording paper stored in the paper feed cassette 71 one by one toward the transport unit 80. A first paper feed sensor 73 for detecting the fed recording paper is provided at the outlet of each paper feed cassette 71.

  The conveyance unit 80 passes the secondary transfer point D or the fixing device 42 through the secondary transfer location D or the fixing device 42 and discharges the recording paper coming from the paper feeding cassette 71 to the discharge tray outside the apparatus, and the recording paper passing through the fixing device 42. And a reversing path 80b for reversing the normal transfer path 80a upstream of the secondary transfer portion D and reversing the front and back. Each of the paths 80a and 80b has a large number of conveying rollers 81 at an interval shorter than the size of the minimum size recording paper in the feeding direction.

  A front end detection sensor 82 for detecting the front end of the recording paper is provided slightly before the transfer point D in the transport unit 80, and a second paper feed roller 83 is provided slightly before that. A second paper feed sensor 84 for detecting that the transfer paper has arrived is disposed slightly before the second paper feed roller 83.

  When the image data of the next page is not prepared, the recording paper sent out from the paper feed cassette 71 is temporarily stopped before the second paper feed roller 83, and is conveyed when the image data is prepared. Resumed. In addition, electrostatic latent images are formed by the laser units 55Y, 55M, 55C, and 55K with reference to the timing when the tip detection sensor 82 detects the tip.

[Charging device]
Each of the charging devices 52Y, 52M, 52C, and 52K (collectively referred to as “charging device 52”) is a corona discharger that generates charges for charging the photosensitive drums 51Y, 51M, 51C, and 51K. It is comprised including.

  The configuration of the charging device 52 will be described with reference to FIGS. 2 is a schematic top view of the charging device 52, FIG. 3 is a schematic side view of the charging device 52, and FIG. 4 is a schematic perspective view of the cleaning member.

  The charging device 52 includes a shield member 100 of a corona discharger. The shield member 100 is formed in a hollow box shape. A wire electrode 101 is stretched along the longitudinal direction of the shield member 100. This corona discharger has the same configuration as the conventional one.

  The corona discharger is provided with a cleaning device (discharge electrode cleaning device) for cleaning the wire electrode 101. The cleaning member 200 of this cleaning device includes a pair of pads 201 and 202 disposed so as to sandwich the wire electrode 101 from both sides. The pad holding unit 203 holds the pads 201 and 202 at its upper end. A slider 204 is fixed to the lower end portion of the pad holding portion 203.

  A predetermined gap is formed between the upper surface of the slider 204 and the shield member 100. A contact member 205 is erected on the upper surface of the slider 204. The contact member 205 is formed shorter than the distance between the upper surface of the slider 204 and the lower surface of the shield member 100. Although details will be described later, the abutting member 205 acts to abut against the elastic members G1 to G3 and H1 to H5 when the slider 204 is moved. The pad holding portion 203, the slider 204, and the contact member 205 correspond to an example of the “holding portion” in the present invention.

  The slider 204 has a through hole 204a as shown in FIG. A guide shaft 206 is inserted through the through hole 204a. The guide shaft 206 forms a path of the cleaning member 200 (reciprocating motion; described later). In other words, the cleaning member 200 acts on the track along the axial direction of the guide shaft 206 to clean the wire electrode 101.

  On the surface of the guide shaft 206, spiral irregularities are formed along the axial direction. That is, the guide shaft 206 functions as a male screw. In addition, on the inner surface of the through hole 204a, the same spiral irregularities that engage with the spiral irregularities of the guide shaft 206 are formed. That is, the slider 204 functions as a female screw.

  A gear 207 is fixed to one end of the guide shaft 206. The guide shaft 206 is provided on the rotation center of the gear 207. A drive gear 208 is engaged with the gear 207. A drive shaft 209 a of the motor 209 is fixed on the rotation center of the drive gear 208. The motor 209 can rotate the drive shaft 209a in the forward direction and the reverse direction.

  The operation of such a cleaning device will be described. When the motor 209 rotates the drive shaft 209a, the drive gear 208 and the gear 207 are rotated. As the gear 207 rotates, the guide shaft 206 is rotated. As described above, the guide shaft 206 functions as a male screw, and the slider 204 functions as a female screw. Therefore, the slider 204 moves in a direction corresponding to the rotation direction of the guide shaft 206 (any direction in the longitudinal direction of the shield member 100 (the x direction shown in FIG. 2)). When the motor 209 rotates the drive shaft 209a in the opposite direction, the slider 204 moves in the opposite direction. In this way, the cleaning member 200 is moved in the longitudinal direction of the shield member 100 (that is, moved along the wire electrode 101).

  When the wire electrode 101 is not cleaned, the cleaning member 200 is disposed at the standby position (home position) P1. At this time, the cleaning member 200 is detached from the wire electrode 101 by an attaching / detaching mechanism (not shown). When cleaning is performed, the cleaning member 200 is attached to the wire electrode 101 by the attachment / detachment mechanism, and the pads 201 and 202 are sandwiched between the wire electrodes 101. The cleaning member 200 cleans the wire electrode 101 while moving along the wire electrode 101 based on the driving force output by the motor 209.

  Elastic members G1 to G3 and H1 to H5 are provided on the lower surface of the shield member 100. Specific examples of the elastic members G1 to G3 and H1 to H5 will be described. First, a plate-like member is formed from an elastic material such as rubber or plastic. Then, the upper end portion of the plate member is fixed to the lower surface of the shield member 100 so that both surfaces of the plate member are oriented in the longitudinal direction of the shield member 100.

  Each of the elastic members G1 to G3 and H1 to H5 has a size set in advance so that the lower end portion thereof is located below the upper end of the contact portion 205. Accordingly, when the contact member 205 moves together with the slider 204, the upper end of the contact member 205 comes into contact with the elastic members G1 to G3 and H1 to H5. Then, the elastic members G1 to G3 and H1 to H5 are bent and deformed by the force received from the contact member 205.

  The elastic members G1 to G3 and H1 to H5 are formed in advance so as to exhibit a predetermined restoring force (repulsive force). The restoring forces of the elastic members G1 to G3 and H1 to H5 act in the direction opposite to the moving direction of the contact member 205. Therefore, the cleaning member 200 receives a load in the direction opposite to the moving direction by the elastic members G1 to G3 and H1 to H5. When the moving cleaning member 200 receives a load, the amount of current supplied to the motor 209 is increased, and the driving force output by the motor 209 is increased.

  In addition, the restoring force by each elastic member G1-G3, H1-H5 is preset so that the motor 209 may not fully lock. That is, the restoring force by each of the elastic members G1 to G3 and H1 to H5 does not have enough force to stop the movement of the cleaning member 200. In addition, each elastic member G1-G3, H1-H5 may be set so that (substantially) the same restoring force may be exhibited, or it may be set so that each may show a different restoring force. Good.

  The elastic members G1 to G3 are provided in the vicinity of the standby position P1 (the standby position P1 is located between the elastic members G2 and G3). H1 to H5 are provided in the vicinity of the reversal position P2 (the reversal position P2 is located between the elastic members H2 and H3). The elastic members G1 to G3 and the elastic members H1 to H5 are provided via predetermined intervals, respectively. The elastic members G1 to G3 and the elastic members H1 to H5 may be arranged at equal intervals, or may be arranged at different intervals.

  In this embodiment, three elastic members G1 to G3 are provided on the standby position P1 side, and five elastic members H1 to H5 are provided on the reverse position P2 side in order to realize an operation mode described later. . When other operation modes are applied, different numbers of elastic members are appropriately provided on the standby position P1 side and the reverse position P2 side.

[Control system]
The configuration for controlling the operation of the cleaning device as described above will be described with reference to FIG. The image forming apparatus 10 includes a power supply 300, a motor current monitoring unit 301, a position specifying unit 302, and a control unit 303.

(Power supply)
The power supply 300 applies a voltage or supplies a current to each part of the image forming apparatus 10 such as the motor 209. The power source 300 converts, for example, an AC power input from the outside into a DC power source and supplies it to each part of the image forming apparatus 10. The power source that supplies current to the motor 209 and the power source that applies voltage to the wire electrode 101 may be the same, or may be provided individually.

(Motor current monitor)
The motor current monitoring unit 301 monitors the current value of the current supplied from the power supply 300 to the motor 209. The motor current monitoring unit 301 includes an ammeter that detects a current value of a current (motor current) applied to the motor 209. The motor current monitoring unit 301 inputs information on the detected motor current value to the position specifying unit 302.

  For example, the motor current monitoring unit 301 periodically detects the motor current and sends the detection result to the position specifying unit 302. The detection interval of the motor current can be determined based on, for example, the moving speed of the cleaning member 200, the length of the guide shaft 206, the installation intervals of the elastic members G1 to G3, and H1 to H5.

  In particular, the detection interval of the motor current is set so that a change in each motor current can be detected when the cleaning member 200 sequentially passes through adjacent elastic members (eg, G1 and G2). For this purpose, by repeating detection at short intervals such as several tenths of a second, for example, a waveform indicating a temporal change in the motor current (discrete data, but substantially “continuous waveform”). Can be estimated). The motor current monitoring unit 301 functions as an example of the “monitoring unit” of the present invention.

(Location identification part)
The position specifying unit 302 performs processing for specifying the position of the cleaning member 200 on the track formed by the guide shaft 206 based on the monitoring result of the motor current value by the motor current monitoring unit 301.

  The position specifying unit 302 includes a microprocessor such as a CPU (Central Processing Unit) or MPU (Micro Processing Unit), and a storage device such as a RAM (Random Access Memory), a ROM (Read Only Memory), and a hard disk drive. Is done.

  A computer program for executing processing for specifying the position of the cleaning member 200 is stored in advance in a storage device such as a ROM or a hard disk drive. The microprocessor develops this computer program on the RAM and executes position specifying processing.

  The position specifying unit 302 is provided with a load pattern storage unit 302a. The load pattern storage unit 302a stores in advance the form of the load (load pattern) applied to the cleaning member 200 by the elastic members G1 to G3 and H1 to H5. The load pattern storage unit 302a is configured by a storage device such as a hard disk drive.

  The load pattern stored in the load pattern storage unit 302a includes the number and interval of the elastic members G1 to G3 and H1 to H5, and the magnitude of the restoring force exhibited by each of the elastic members G1 to G3 and H1 to H5. (These are preset as described above.)

  The former (number and interval) is a pattern of a load applied to the cleaning member 200 when the moving cleaning member 200 passes through the elastic members G1 to G3, for example, a change in motor current applied to the motor 209 ( This includes information on the number of “crests” in the waveform indicating the motor current, the interval between adjacent “crests” and “crests”, and the like.

  The latter (the magnitude of the restoring force) is the magnitude of the load that each elastic member G1 to G3, H1 to H5 applies to the cleaning member 200 passing therethrough, for example, the change in motor current applied to the motor 209 ( Information on the height of the “mountain” in the waveform indicating the motor current. Motor current values (heights of “mountains”) corresponding to the elastic members G1 to G3 and H1 to H5 are set to about 300 mA, for example.

  Further, the width of each “mountain” of the motor current waveform, that is, the time during which the moving cleaning member 200 is loaded by the elastic members G1 to G3 and H1 to H5 can be set as the load pattern. The width of each “mountain” is set to about 200 ms, for example.

  With reference to FIG. 6, the load pattern by elastic member G1-G3, H1-H5 is demonstrated. A graph W illustrated in FIG. 6 represents a change in the motor current when the cleaning member 200 is moved from the elastic member G3 side toward the elastic member H5 at a constant speed (excluding immediately after the start of movement and immediately after the end of movement). The waveform is shown.

  The peaks g1 to g3 and h1 to h5 in the graph W correspond to “mountains” of values of the motor current when the cleaning member 200 passes through the elastic members G1 to G3 and H1 to H5, respectively. Points p1 and p2 correspond to the standby position P1 and the reverse position P2, respectively.

  The motor current value when the cleaning member 200 passes through positions other than the elastic members G1 to G3 and H1 to H5 is i1. The motor current value (height of “mountain”) when the cleaning member 200 passes through the elastic members G1 to G3 and H1 to H5 is i2. Here, i2> i1.

  The interval (time interval) between the adjacent peaks gi, g (i + 1) corresponding to the adjacent elastic members Gi, G (i + 1) (i = 1, 2) is Δw1. Since the cleaning member 200 moves at a constant speed (= v), the distance between the adjacent elastic members Gi and G (i + 1) is v × Δw1. Similarly, the time interval between adjacent mountains hj, h (j + 1) (j = 1 to 4) in the graph W is Δw1, and the distance interval between adjacent elastic members Hj, H (j + 1) is v ×. Δw2.

  The width of each mountain gi, hj in the graph W is Δt.

  The load pattern storage unit 302a has, as a load pattern, the motor current value (crest height) i2 described above, the interval between adjacent peaks Δw1, Δw2, the width Δt of each peak, the number of peaks, Information such as position is stored. In the storage device of the position specifying unit 302, the contact member 205 is in contact with the elastic members G1 to G3 and H1 to H5 and is supplied to the motor 209 when the cleaning member 200 receives a restoring force. A threshold value for detecting the current is stored in advance.

  This threshold value is a value set in advance by the motor 209, and is set, for example, between the motor current values i1 and i2 shown in FIG. Further, it is desirable that this threshold value is set to a value larger than the noise caused by the distortion of the guide shaft 206 and the manufacturing error of each elastic member G1 and the like. However, if the peak width Δt is set to be sufficiently larger than the normal noise width, a threshold value smaller than the noise can be set. Note that the magnitude of noise can be obtained by actual measurement in advance or can be obtained by simulation. As a specific example, the threshold value is set to (i1 + i2) / 2.

  The waveform of the motor current value detected when the cleaning member 200 is actually moved includes, for example, noise due to distortion of the guide shaft 206, manufacturing errors of the elastic members G1 to G3, and H1 to H5. It becomes a waveform.

  The position specifying unit 302 compares the monitoring result (motor current value waveform) input from the motor current monitoring unit 301 with the load pattern stored in the load pattern storage unit 302a, thereby determining the position of the cleaning member 200. Identify. Specific contents of the position specifying process will be described later. The position specifying unit 302 functions as an example of the “specifying unit” of the present invention.

(Control part)
The control unit 303 moves the cleaning member 200 along the track by controlling the operation of the motor 209. For example, the control unit 303 controls the current (current value, current direction of DC current (direction in which the voltage is applied)) supplied from the power source 300 to the motor 209, thereby controlling the moving direction and moving speed of the cleaning member 200. It comes to control.

  More specifically, the control unit 303 controls the operation of the motor 209 based on the position of the cleaning member 200 specified by the position specifying unit 302, so that the cleaning member 200 starts moving, stops moving, reverses, etc. To implement. Specific control contents by the control unit 303 will be described later.

  The control unit 303 includes a microprocessor such as a CPU, a storage device such as a RAM, a ROM, and a hard disk drive. A storage device such as a hard disk drive stores in advance a computer program for the microprocessor to execute the control content described later. The control unit 303 functions as an example of the “control unit” of the present invention.

  Note that the microprocessor and storage device constituting the control unit 303 and the microprocessor and storage device constituting the position specifying unit 302 may be provided separately or the same. However, the position specifying unit 302 and the control unit 303 operate in conjunction with each other to realize the operation according to the present embodiment.

[Mode of operation]
The operation of the image forming apparatus 10 according to the present embodiment configured as described above will be described. The flowcharts shown in FIGS. 7 and 8 each show an example of the cleaning operation of the wire electrode 101 by the image forming apparatus 10.

[First operation mode]
First, the first operation mode of the image forming apparatus 10 will be described with reference to the flowchart of FIG. This operation mode is an example of an operation of cleaning the wire electrode 101 by moving the cleaning member 200 disposed at the standby position P1 to the reverse position P2, and further reversing the moving direction to guide to the standby position P1. It is.

  Before the start of the cleaning operation, the cleaning member 200 is assumed to be disposed at the standby position P1. That is, the contact member 205 of the cleaning member 200 is initially disposed between the elastic members G2 and G3.

  As shown in FIGS. 2, 3, and 6, the reverse position P <b> 2 passes through the elastic members G <b> 2 and G <b> 1 from the standby position P <b> 1, and is a position immediately after passing through the elastic members H <b> 1 and H <b> 2 after a while. The load pattern storage unit 302a stores in advance various information such as the load pattern related to the elastic member G1 and the like described above.

  When an instruction to clean the wire electrode 101 (manual instruction or automatic instruction) is given, the control unit 303 controls the power supply 300 to supply a current to the motor 209 to move the cleaning member 200 in the reverse position P2 direction. The movement is started (S1).

  The motor current monitoring unit 301 detects the value of the motor current at a predetermined time interval, and inputs the detected value to the position specifying unit 302 (S2).

  The position specifying unit 302 determines whether the detected value of the motor current input from the motor current monitoring unit 301 exceeds the above-described threshold (S3). When it is determined that the detected value does not exceed the threshold value (S3; N), steps S2 and S3 are repeated.

  When it is determined that the detected value of the motor current exceeds the threshold (S3; Y), the position specifying unit 302 determines whether or not the state where the detected value exceeds the threshold continues for a predetermined time t1 or more (S4). . The predetermined time t1 is set in advance based on the mountain width Δt in FIG. 6 (for example, t1 = Δt / 2).

  Step S4 determines whether or not the detected motor current is noise. If the state where the detected value exceeds the threshold value does not continue for the predetermined time t1 or longer (S4; N), the detected motor current is assumed to be noise, and the process returns to step S2 to monitor the motor current.

  On the other hand, when the state where the detected value exceeds the threshold value continues for the predetermined time t1 or longer (S4; Y), the position specifying unit 302 determines that the detected motor current is not noise.

  Further, the position specifying unit 302 determines whether the state where the detected value exceeds the threshold value continues for a predetermined time t2 (> t1) or longer (S5). The predetermined time t2 is set in advance based on the mountain width Δt in FIG. 6 (for example, t2 = Δt).

  Step S5 determines whether or not the detected motor current is due to the full lock of the motor 209. That is, when the motor 209 is fully locked, the detection value (overcurrent) exceeding the threshold value continues for a predetermined time t2 or more, so that the occurrence of full lock can be detected by detecting this continuous overcurrent. it can.

  When the state where the detected value exceeds the threshold value continues for a predetermined time t2 or longer (S5; Y), the position specifying unit 302 determines that the motor 209 is fully locked, and sends a signal (stop request signal) to the control unit 303. Send. Upon receiving the stop request signal, the control unit 303 controls the power supply 300 to end the current supply to the motor 209 (S10), and ends the cleaning operation of the wire electrode 101.

  In this case, for example, the wire electrode 101 is manually cleaned or the cleaning member 200 is moved to the standby position P1. Alternatively, the cleaning member 200 may be moved to the standby position P1 by automatically rotating the motor 209 in the reverse direction.

  When the state where the detected value exceeds the threshold value does not continue for the predetermined time t2 or longer (S5; N), the position specifying unit 302 determines that the cleaning member 200 has passed the position of the elastic member G2, The counter value (not shown) is incremented by “+1” (S6). Note that the value of this counter is initially set to “0”.

  The position specifying unit 302 determines whether the value of the counter has reached “4” (S7). If the value of the counter has not reached “4” (S7; N), the position specifying unit 302 determines that it has not yet reached the reverse position P2, and returns to step S2.

  The above processing is repeated until “Y” is determined in step S7, that is, until the value of the counter reaches “4”. When the value of the counter reaches “4” (S7; Y), the position specifying unit 302 determines that the cleaning member 200 has reached the reverse position P2, and sends a signal (reverse request signal) to the control unit 303. Upon receiving the reversal request signal, the control unit 303 controls the power supply 300 to stop the current supply to the motor 209 and apply a reverse voltage to reverse the moving direction of the cleaning member 200 (S8). The position specifying unit 302 returns the counter value to “0”.

  The motor current monitoring unit 301 detects the value of the inverted motor current at a predetermined time interval, and inputs the detected value to the position specifying unit 302 (S2). And the cleaning member 200 is moved to the standby position P1 by implementing the process similar to step S2-S7 (S9). The control unit 303 controls the power supply 300 to end the current supply to the motor 209 (S10). With the above, the cleaning operation of the wire electrode 101 according to this operation mode is completed.

[Second operation mode]
Next, a second operation mode of the image forming apparatus according to the present embodiment will be described. This operation mode is an example of an operation for guiding the cleaning member 200 to the standby position P1 when returning from a state in which the power is turned off while the wire electrode 101 is being cleaned.

  As described above, the cleaning member 200 is released from the contact state with the wire electrode 101 at the standby position P1. This operation mode allows the discharge from the wire electrode 101 to be suitably performed by guiding the cleaning member 200 in a state where the cleaning is interrupted to the standby position P1.

  In this operation mode, cleaning is performed by controlling the motor 209 in accordance with the initial position of the cleaning member 200 (the contact member 205 thereof), that is, the position of the cleaning member 200 when the cleaning is interrupted (referred to as the initial position). A specific example of guiding the member 200 to the standby position P1 will be described.

  When the cleaning of the wire electrode 101 is interrupted, the initial position of the cleaning member 200 is one of the following six positions: (1) a position between the elastic members G2 and G3 (standby position P1); (2 ) A position between the elastic members G1 and G2; (3) A position between the elastic members G1 and H1 (except for the following (4)); (4) Between the elastic members G1 and H1 and the elastic member H1. (5) a position between the elastic members H1 and H2; (6) a position between the elastic members H2 and H3 (reverse position P2).

  Hereinafter, the process of guiding the cleaning member 200 to the standby position P1 will be described for each case of (1) to (6). An example of the operation content of the image forming apparatus 10 in each case of (1) to (6) is shown in FIG.

  (1) When a return request (manual or automatic) to the standby position P1 is made after the interruption of the cleaning of the wire electrode 101, the control unit 303 controls the motor 209 to move the cleaning member 200 in the direction of the reverse position P2 (see FIG. 2. Move it to the right in FIG.

  The position specifying unit 302 detects that the cleaning member 200 has passed the position of the elastic member in the same manner as in the first operation mode. The position specifying unit 302 confirms that the cleaning member 200 has passed two elastic members (here, elastic members G2 and G1) within a predetermined time T1.

  The predetermined time T1 is set in advance in consideration of the moving speed of the cleaning member 200, the width Δt of the elastic member Gi, the interval Δw1 between the adjacent elastic members Gi, G (i + 1) (i = 1, 2), and the like. Is done. The predetermined time T1 can be set, for example, to a value that is about the time required to pass through two adjacent elastic members Gi and G (i + 1).

  When it is confirmed that the cleaning member 200 has passed the two elastic members within the predetermined time T1, the position specifying unit 302 confirms that the position of the elastic member does not pass during the elapse of the predetermined time T2.

  Here, the predetermined time T2 is set in advance in consideration of the moving speed of the cleaning member 200, the distance between the elastic members G1 and H1, and the like. This predetermined time T2 can be set to a value of about the time taken to move about half of the distance between the elastic members G1, H1, for example.

  When it is confirmed that the two elastic members have been passed within the predetermined time T1 and that the position of the elastic member has not been passed within the predetermined time T2, the position specifying unit 302 determines that the cleaning member is based on the confirmation contents. 200 positions are specified. In this case, it is determined that the cleaning member 200 exists between the elastic member G1 and the elastic member H1. That is, it can be seen that when the cleaning of the wire electrode 101 is interrupted, the cleaning member 200 is located between the elastic member G2 and the elastic member G3. The position specifying unit 302 sends this position specifying result to the control unit 303.

  The controller 303 guides the cleaning member 200 to the standby position P1 by controlling the motor 209 based on the position specifying result. Specifically, the control unit 303 reverses the moving direction of the cleaning member 200 toward the reversal position P2 and stops the cleaning member 200 after passing the two elastic members G1 and G2.

  (2) When a return request (manual or automatic) to the standby position P1 is made after interruption of the cleaning of the wire electrode 101, the control unit 303 controls the motor 209 to move the cleaning member 200 in the direction of the reverse position P2. Let

  The position specifying unit 302 confirms that the cleaning member 200 has passed one elastic member (here, the elastic members G2 and G1) within the predetermined time T1. This predetermined time T1 can be set to a value of about the time taken to pass through two adjacent elastic members Gi, G (i + 1), for example, as in the case of (1).

  When it is confirmed that the cleaning member 200 has passed one elastic member within the predetermined time T1, the position specifying unit 302 confirms that the position of the elastic member does not pass while the predetermined time T2 elapses. This predetermined time T2 can be set to a value of about the time required to move about half of the distance between the elastic members G1 and H1, for example, as in (1).

  When it is confirmed that one elastic member has been passed within the predetermined time T1 and that the position of the elastic member has not been passed during the predetermined time T2, the position specifying unit 302 determines that the cleaning member is based on the confirmation content. 200 positions are specified. In this case, it is determined that the cleaning member 200 exists between the elastic member G1 and the elastic member H1. That is, it can be seen that when the cleaning of the wire electrode 101 is interrupted, the cleaning member 200 is located between the elastic member G1 and the elastic member G2. The position specifying unit 302 sends this position specifying result to the control unit 303.

  The controller 303 guides the cleaning member 200 to the standby position P1 by controlling the motor 209 based on the position specifying result. Specifically, the control unit 303 reverses the moving direction of the cleaning member 200 toward the reversal position P2 and stops the cleaning member 200 after passing the two elastic members G1 and G2.

  (3) When a return request (manual or automatic) to the standby position P1 is made after interruption of the cleaning of the wire electrode 101, the control unit 303 controls the motor 209 to move the cleaning member 200 in the direction of the reverse position P2. Let

  The position specifying unit 302 confirms that the cleaning member 200 does not pass through the position of the elastic member while the predetermined time T3 has elapsed.

  The predetermined time T3 includes the moving speed of the cleaning member 200, the width Δt of the elastic members Gi and Hj, the interval Δw1 between the elastic members Gi and G (1 + i), the interval Δw2 between the elastic members Hj and H (j + 1), The distance is set in advance in consideration of the distance between the elastic members G1 and H1. The predetermined time T3 is set, for example, larger than the interval Δw1 between the elastic members Gi, G (1 + i) and the interval Δw2 between the elastic members Hj, H (j + 1) and smaller than the distance between the elastic members G1, H1. (For example, about 1/5 of the distance between the elastic members G1 and H1).

  When it is confirmed that the position of the elastic member does not pass during the predetermined time T3, the position specifying unit 302 specifies the position of the cleaning member 200 based on the confirmation content. In this case, it is determined that the cleaning member 200 exists between the elastic member G1 and the elastic member H1. That is, when the cleaning of the wire electrode 101 is interrupted, the cleaning member 200 is located between the elastic member G1 and the elastic member H1 (for example, a position where the space between the elastic members G1 and H1 is internally divided into 4: 1). It can be seen that it was located on the elastic member G1 side). The position specifying unit 302 sends this position specifying result to the control unit 303.

  The controller 303 guides the cleaning member 200 to the standby position P1 by controlling the motor 209 based on the position specifying result. Specifically, the control unit 303 reverses the moving direction of the cleaning member 200 toward the reversal position P2 and stops the cleaning member 200 after passing the two elastic members G1 and G2.

  (4) When a return request (manual or automatic) to the standby position P1 is made after the cleaning of the wire electrode 101 is interrupted, the control unit 303 controls the motor 209 to move the cleaning member 200 in the direction of the reverse position P2. Let

  The position specifying unit 302 confirms that the cleaning member 200 has passed the positions of the five elastic members (H1 to H5) while the predetermined time T4 has elapsed.

  The predetermined time T4 is set in advance in consideration of the moving speed of the cleaning member 200, the width Δt of the elastic member Hj, the interval Δw2 between the elastic members Hj and H (j + 1), and the like. The predetermined time T4 can be set to a time slightly longer than, for example, the time taken to pass through the elastic members H1 to H5.

  In order to suitably perform the processes (4) to (6), the distance between the inner wall of the shield member 100 on the reversing position P2 side in the longitudinal direction and the elastic member H5 is set to be equal to two elastic members Hj. It is desirable that the distance is about (2 × Δt + Δw1). Thereby, especially in the case of (5) and (6), the situation where the cleaning member 200 collides with the inner wall of the shield member 100 and the motor 209 is fully locked can be avoided.

  When it is confirmed that the positions of the five elastic members H1 to H5 have passed during the predetermined time T4, the position specifying unit 302 specifies the position of the cleaning member 200 based on the confirmation contents. In this case, it is determined that the cleaning member 200 exists between the elastic member H5 and the inner wall of the shield member 100. That is, when the cleaning of the wire electrode 101 is interrupted, the cleaning member 200 is located between the elastic member G1 and the elastic member H1 and in the vicinity of the elastic member H1. The position specifying unit 302 sends this position specifying result to the control unit 303.

  The controller 303 guides the cleaning member 200 to the standby position P1 by controlling the motor 209 based on the position specifying result. Specifically, the control unit 303 reverses the moving direction of the cleaning member 200 toward the reversal position P2, passes the five elastic members H5 to H1, and further passes the two elastic members G1 and G2. The cleaning member 200 is stopped later.

  (5) When a return request (manual or automatic) to the standby position P1 is made after the cleaning of the wire electrode 101 is interrupted, the control unit 303 controls the motor 209 to move the cleaning member 200 in the direction of the reverse position P2. Let

  The position specifying unit 302 confirms that the cleaning member 200 has passed the positions of the four elastic members (H1 to H5) while the predetermined time T4 has elapsed. The predetermined time T4 is set to a time slightly longer than the time taken to pass through the elastic members H1 to H5, for example, as in the case of (4).

  When it is confirmed that the positions of the four elastic members H1 to H5 have passed during the predetermined time T4, the position specifying unit 302 specifies the position of the cleaning member 200 based on the confirmation contents. In this case, it is determined that the cleaning member 200 exists between the elastic member H5 and the inner wall of the shield member 100. That is, it can be seen that when the cleaning of the wire electrode 101 was interrupted, the cleaning member 200 was located between the elastic member H1 and the elastic member H2. The position specifying unit 302 sends this position specifying result to the control unit 303.

  The controller 303 guides the cleaning member 200 to the standby position P1 by controlling the motor 209 based on the position specifying result. Specifically, the control unit 303 reverses the moving direction of the cleaning member 200 toward the reversal position P2, passes the five elastic members H5 to H1, and further passes the two elastic members G1 and G2. The cleaning member 200 is stopped later.

  (6) When a return request (manually or automatically) to the standby position P1 is made after the cleaning of the wire electrode 101 is interrupted, the control unit 303 controls the motor 209 to move the cleaning member 200 in the direction of the reverse position P2. Let

  The position specifying unit 302 confirms that the cleaning member 200 has passed the positions of the three elastic members (H1 to H5) while the predetermined time T4 has elapsed. The predetermined time T4 is set to a time slightly longer than the time taken to pass through the elastic members H1 to H5, for example, as in the case of (4).

  When it is confirmed that the positions of the three elastic members H1 to H5 have passed during the predetermined time T4, the position specifying unit 302 specifies the position of the cleaning member 200 based on the confirmation contents. In this case, it is determined that the cleaning member 200 exists between the elastic member H5 and the inner wall of the shield member 100. That is, when cleaning of the wire electrode 101 is interrupted, it can be seen that the cleaning member 200 was positioned between the elastic member H2 and the elastic member H3. The position specifying unit 302 sends this position specifying result to the control unit 303.

  The controller 303 guides the cleaning member 200 to the standby position P1 by controlling the motor 209 based on the position specifying result. Specifically, the control unit 303 reverses the moving direction of the cleaning member 200 toward the reversal position P2, passes the five elastic members H5 to H1, and further passes the two elastic members G1 and G2. The cleaning member 200 is stopped later.

(Action / Effect)
The operation and effect of the image forming apparatus 10 operating as described above will be described.

  The image forming apparatus 10 includes elastic members G1 to G3 and H1 to H5, a motor 209, a motor current monitoring unit 301, and a position specifying unit 302.

  The motor 209 outputs a driving force for moving the cleaning member 200. Each elastic member Gi, Hj is provided on the orbit of the reciprocating movement of the cleaning member 200, and applies a load to the cleaning member 200 in the direction opposite to the moving direction when the cleaning member 200 passes (that is, Giving a force that acts to hinder movement).

  This load is set to a force that allows the cleaning member 200 to pass by the driving force of the motor 209. That is, the magnitude of the load by the elastic members Gi and Hj is set so that the motor 209 does not fully lock even when the cleaning member 200 reaches the position of the elastic members Gi and Hj.

  The motor current monitoring unit 301 monitors a current (motor current) supplied from the power supply 300 to the motor 209. When the cleaning member 200 passes through the positions of the elastic members Gi and Hj, the motor current increases due to the load in the direction opposite to the moving direction. The position specifying unit 302 specifies the position of the cleaning member 200 on the reciprocating track based on the monitoring result of the motor current by the motor current monitoring unit 301.

  As described above, the image forming apparatus 10 is configured to identify the position of the cleaning member 200 based on the change in the motor current caused by the elastic members Gi and Hj. Therefore, the image forming apparatus 10 performs cleaning while avoiding the full lock of the motor 209. It is possible to detect the position of the member 200 (particularly, the standby position P1 and the reverse position P2). Therefore, it is possible to reduce the burden on the wire electrode 101 and the winding of the motor 209 when the wire electrode 101 is cleaned.

  In addition, the position specifying unit 302 according to the present embodiment acts to specify the position of the cleaning member 200 based on the moving direction of the cleaning member 200 together with the monitoring result of the motor current. The cleaning member 200 cleans the wire electrode 101 by reciprocating along the longitudinal direction of the shield member 100. Therefore, by considering the moving direction of the cleaning member 200 together with the monitoring result of the motor current, the position of the cleaning member 200 can be specified more easily and reliably.

  In the present embodiment, a plurality of elastic members Gi and Hj are provided on the track of the cleaning member 200. The elastic members Gi and Hj are disposed via predetermined intervals Δw1 and Δw2. The motor current monitoring unit 301 outputs a waveform indicating a time change of the motor current as a monitoring result. The position specifying unit 302 operates to specify the position of the cleaning member 200 on the track by comparing the waveform of the motor current with the distances Δw1 and Δw2 (load patterns) of the elastic members Gi and Hj.

  Further, the elastic members Gi and Hj are arranged so as to apply a load to the cleaning member 200 by a preset load amount. Accordingly, the driving force output by the motor 209 to move the cleaning member 200 is increased by an increase amount Δi (= i2−i1; see FIG. 6) corresponding to the load amount (load amount and increase amount). Is assumed to be known). The position specifying unit 302 operates to specify the position of the cleaning member 200 on the track by comparing the waveform as the monitoring result of the motor current with the increase amount Δi (load pattern) of the motor current.

  Thus, by comparing the preset load pattern with the waveform of the motor current, the position of the cleaning member 200 can be easily and reliably specified.

  In the image forming apparatus 10 according to the present embodiment, the cleaning members 200 are positioned at the standby position P1 by disposing the elastic members Gi and Hj near the standby position P1 and the reverse position P2, respectively. It is distinguished from being located at the reversal position P2. Thereby, the elastic member 200 can be reliably reciprocated.

  In addition, the image forming apparatus 10 according to the present embodiment controls the motor 209 based on the position of the cleaning member 200 specified by the position specifying unit 302 to stop the movement of the cleaning member 200 or move the cleaning member 200. It works to reverse the direction. This control is executed by the control unit 303. According to the image forming apparatus 10 acting in this way, the wire electrode 101 can be reliably cleaned regardless of the position of the cleaning member 200 before the start of cleaning.

  In addition, the image forming apparatus 10 according to the present embodiment controls the motor 209 based on the position of the cleaning member 200 specified by the position specifying unit 302 to start the reciprocating movement of the cleaning member 200 (standby position P1). Acts to move up to. This control is executed by the control unit 303. As described above, the cleaning member 200 is released from the contact state with the wire electrode 101 at the standby position P1. Therefore, according to the image forming apparatus 10 acting in this way, the reciprocating movement between the standby position P1 and the reverse position P2 can be reliably performed, and the cleaning member 200 contacts the wire electrode 101 after the cleaning is completed. It is possible to reliably release the state.

  Moreover, according to the image forming apparatus 10 according to the present embodiment, as described in the second operation mode, when the power is turned off while the wire electrode 101 is being cleaned, the power is turned off. Regardless of the position of the cleaning member 200, the cleaning member 200 can be reliably guided to the standby position P1.

  Further, according to the image forming apparatus 10 according to the present embodiment, it is not necessary to provide a micro switch or a micro sensor for detecting the position of the cleaning member, and thus the discharge electrode cleaning apparatus can be downsized. Such a small cleaning device is particularly effective in an image forming apparatus capable of color output having four sets of image forming components such as a photosensitive drum.

[Modification]
Embodiment described above is only an example for implementing this invention suitably. Therefore, for example, various modifications within the scope of the gist of the present invention described below can be appropriately made.

  In the above embodiment, the elastic member Gi, Hj made of a plate-like member formed of a material having elasticity (flexibility) such as rubber or plastic is applied with a load on the cleaning member 200 passing through the position. It has become. The elastic members Gi and Hj are disposed so as to come into contact with the cleaning member 200 passing therethrough, and give a load by a restoring force from deformation due to the contact. At this time, in order to move the cleaning member 200 against this load, a larger motor current is supplied to the motor 209 and the driving force is increased.

  Thus, the elastic members Gi and Hj act so as to apply a load in the direction opposite to the moving direction to the cleaning member 200 passing through the position. When such a load is applied, the driving force output by the motor 209 to move the cleaning member 200 is increased.

  The elastic members Gi and Hj function as an example of the “load applying unit” in the present invention. Further, the elastic members Gi and Hj correspond to an example of the “load applying member” of the present invention disposed so as to contact the moving cleaning member 200 and apply a load.

  The load applying means, the load applying member, and the elastic member according to the present invention are not limited to the elastic members Gi and Hj having such flexibility, and any configuration capable of exhibiting the above action is applied. can do.

  For example, a leaf spring K as shown in FIG. 9 may be used to apply a load to the cleaning member 200 passing through the position. The leaf spring K is disposed on the lower surface of the shield member 100. The leaf spring K abuts against the abutting member 205 of the cleaning member 200 passing through the position and deforms upward (shield member 100 side), and applies a load to the cleaning member 200 by its restoring force.

  Further, instead of using elasticity, deformation, or flexibility as described above, it is possible to apply a load to the cleaning member 200 using other properties. For example, by disposing a member having a portion with a large friction coefficient at a position in contact with the cleaning member 200 (contact member 205) passing through the position, a load is applied using the frictional force at the time of contact. It can also be configured.

  Further, the load applying means is not limited to the contact type as described above, and a non-contact type load applying means can also be applied. For example, by providing magnets with different polarities on the shield member 100 side and the cleaning device 200 side, a load can be applied to the cleaning member 200 by a magnetic force attracting each other.

  In the above embodiment, the elastic members Gi and Hj (load applying means) are disposed outside the shield member 100. This is due to the fact that the load applying means does not adversely affect the corona discharge caused by the wire electrode 101.

  However, if a sufficient distance is secured between the load applying means and the wire electrode 101 so as to avoid an adverse effect on the corona discharge, the load applying means is provided in the shield member 100. Is also possible.

  The cleaning member 200 can be moved by a predetermined distance, the time taken for this movement (movement time) can be measured, and the position specifying result of the cleaning member 200 can be corrected based on the measurement result.

  The predetermined distance for moving the cleaning member 200 is, for example, an arbitrary distance such as a distance between the standby position P1 and the reversal position P2, a reciprocating movement distance, and a distance between the elastic member G1 and the elastic member H1. Can be set appropriately. The cleaning member 200 is moved under the control of the control unit 303. The movement time can be measured using the time measuring function of the microprocessor constituting the position specifying unit 302. The position specifying unit 302 calculates, for example, a time (unit moving time) required to move a unit distance (for example, 1 cm) based on the measurement result of the moving time, and the cleaning member based on the unit moving time. The result of specifying the position 200 is corrected. Thereby, the position of the cleaning member 200 can be specified more accurately. Since the movement speed changes immediately after the start of movement or immediately before the stop, it is desirable to measure the movement time while ignoring the influence of this range, or to measure the movement time taking into account the influence of this range. .

  In the above embodiment, the elastic members Gi are arranged at equal intervals Δw1 and the elastic members Hj are arranged at equal intervals Δw2, but the arrangement intervals of the load applying means such as elastic members can be arbitrarily set.

  For example, the positions of the cleaning members 200 can be specified by making all the intervals between the adjacent elastic members different and detecting the movement time and the movement distance between the adjacent elastic members.

  Further, by disposing the load applying means so as to be distributed over the entire area of the reciprocating track of the cleaning member 200, the cleaning member 200 is disposed not only at the standby position P1 and the reverse position P2 but also at an arbitrary position on the track. May be detected. Thereby, for example, it is possible to detect that the cleaning member 200 is disposed at an arbitrary position between the elastic member G1 and the elastic member H. Note that the position specifying process of the cleaning member 200 can be facilitated by gradually changing the arrangement interval of the load applying means.

  Moreover, although said embodiment demonstrated the structure which reciprocates between the standby position P1 and the inversion position P2, and cleaned the wire electrode 101, the structure of the said embodiment is also with respect to the thing of another cleaning form. Can be applied mutatis mutandis. For example, when both ends of the wire electrode are set to the standby position (when the contact state of the cleaning member with respect to the wire electrode is released at both ends), the position of the cleaning member is specified or the cleaning member is set to standby by the same configuration. It is possible to guide to a position.

[Discharge electrode cleaning device]
The discharge electrode cleaning device according to the present invention includes a cleaning member that is in contact with a wire electrode that generates electric charge, a driving unit that reciprocates the cleaning member along the wire electrode, and a driving unit that is provided on a reciprocating track. A load applying means for applying a load to the cleaning member in a direction opposite to the moving direction when the cleaning member moved by the monitoring means, a monitoring means for monitoring a current supplied to the driving means, and a monitoring means And a specifying means for specifying the position of the cleaning member on the track based on the current monitoring result.

  The above-described image forming apparatus 10 is obtained by applying the discharge electrode cleaning apparatus according to the present invention to an image forming apparatus. Any configuration mentioned in the above description regarding the image forming apparatus 10 can be applied to the discharge electrode cleaning apparatus according to the present invention.

  According to the discharge electrode cleaning device of the present invention, similarly to the image forming apparatus 10, it is possible to reduce the burden on the wire electrode and the winding of the motor when cleaning the wire electrode. Further, according to the discharge electrode cleaning device according to the present invention, similarly to the image forming device 10, it is possible to reliably guide the cleaning member for cleaning the wire electrode to the standby position.

1 is a schematic side view illustrating an example of a configuration of a preferred embodiment of an image forming apparatus according to the present invention. 1 is a schematic top view illustrating an example of a configuration of a discharge electrode cleaning device in a preferred embodiment of an image forming apparatus according to the present invention. It is a schematic side view showing an example of the structure of the discharge electrode cleaning apparatus in suitable embodiment of the image forming apparatus which concerns on this invention. 2 is a schematic perspective view illustrating an example of a configuration of a cleaning member in a preferred embodiment of the image forming apparatus according to the present invention. FIG. It is a schematic block diagram showing an example of the structure of the control system of the discharge electrode cleaning apparatus in suitable embodiment of the image forming apparatus which concerns on this invention. It is a schematic explanatory diagram for explaining a load pattern by an elastic member in a preferred embodiment of the image forming apparatus according to the present invention. 5 is a flowchart illustrating an example of an operation mode of a preferred embodiment of the image forming apparatus according to the present invention. FIG. 3 is a schematic diagram illustrating an example of an operation mode of a preferred embodiment of the image forming apparatus according to the present invention. It is a schematic side view showing the structure of the modification of the load provision means in suitable embodiment of the image forming apparatus which concerns on this invention.

Explanation of symbols

10 Image forming devices 52, 52Y, 52M, 52C, 52K Charging device 100 Shield member 101 Wire electrode 200 Cleaning member 201, 202 Pad 203 Pad holding portion 204 Slider 204a Through hole 205 Contact member 206 Guide shaft 207 Gear 208 Drive gear 209 Motor 209a Drive shaft 300 Power supply 301 Motor current monitoring unit 302 Position specifying unit 302a Load pattern storage unit 303 Control units G1 to G3, H1 to H5 Elastic member P1 Standby position P2 Reverse position K Leaf spring

Claims (30)

A wire electrode that generates a charge in response to the application of voltage;
A cleaning member in contact with the wire electrode;
Driving means for reciprocating the cleaning member along the wire electrode;
An image forming apparatus that forms an image on a recording material by using electric charges generated from the wire electrode,
A load applying means that is provided on the reciprocating movement track and applies a load to the cleaning member in a direction opposite to the moving direction when the cleaning member moved by the driving means passes;
Monitoring means for monitoring current supplied to the driving means;
Identification means for identifying the position of the cleaning member on the track based on the monitoring result of the current by the monitoring means;
An image forming apparatus comprising: The specifying means specifies the position of the cleaning member based on the current monitoring result and the moving direction of the cleaning member by the driving means.
The image forming apparatus according to claim 1. On the orbit, a plurality of the load applying means are arranged at predetermined intervals,
The specifying unit compares the waveform of the current as the monitoring result with the interval, and specifies the position of the cleaning member on the track,
The image forming apparatus according to claim 1, wherein the image forming apparatus is an image forming apparatus. On the track, a plurality of load applying means are arranged to apply the load to the cleaning member by a preset load amount,
The specifying unit compares the load waveform with the current waveform as the monitoring result, and specifies the position of the cleaning member on the track.
The image forming apparatus according to claim 1, wherein the image forming apparatus is an image forming apparatus. At least one of the plurality of load applying means is provided in the vicinity of the start position of the reciprocating movement,
The specifying means specifies at least that the position of the cleaning member is the start position;
The image forming apparatus according to claim 3, wherein the image forming apparatus is an image forming apparatus. At least one of the plurality of load applying means is provided in the vicinity of the reversal position in the reciprocating movement,
The specifying means specifies at least that the position of the cleaning member is the reverse position;
The image forming apparatus according to claim 3, wherein the image forming apparatus is an image forming apparatus. At least one of the plurality of load applying means is provided in the vicinity of the start position of the reciprocating movement, and at least one of the remaining load applying means is in the vicinity of the reversing position in the reciprocating movement. Provided,
The specifying means identifies and specifies that the cleaning member is located at the start position and the reverse position;
The image forming apparatus according to claim 3, wherein the image forming apparatus is an image forming apparatus. Control means for controlling the drive means to move the cleaning member by a predetermined distance along the reciprocating trajectory;
The specifying means measures a moving time when the specified distance is moved, and corrects the position of the specified cleaning member based on the monitoring result of the current based on the measured moving time.
The image forming apparatus according to claim 1, wherein the image forming apparatus is an image forming apparatus. Control means for controlling the driving means based on the position of the cleaning member specified by the specifying means to stop the movement of the cleaning member or reverse the moving direction of the cleaning member,
The image forming apparatus according to claim 1, wherein the image forming apparatus is an image forming apparatus. Control means for controlling the drive means based on the position of the cleaning member specified by the specifying means to move the cleaning member to the start position of the reciprocating movement.
The image forming apparatus according to claim 1, wherein the image forming apparatus is an image forming apparatus. The load applying means includes a load applying member provided to contact the cleaning member moved by the driving means and apply the load.
The image forming apparatus according to claim 1, wherein the image forming apparatus is an image forming apparatus. The load applying member is an elastic member that is deformed when contacting the cleaning member.
The image forming apparatus according to claim 11. The elastic member is a leaf spring;
The image forming apparatus according to claim 12. The elastic member has flexibility;
The image forming apparatus according to claim 12. The wire electrode constitutes a corona discharger and is provided in a shield member,
The cleaning member has a pad disposed in the shield member and in contact with the wire electrode, and a holding portion that holds the pad at one end and the other end is disposed outside the shield member. And
The load applying means is disposed outside the shield member and contacts the holding portion of the cleaning member.
The image forming apparatus according to claim 11, wherein the image forming apparatus is an image forming apparatus. A cleaning member that is in contact with a wire electrode that generates an electric charge in response to application of a voltage;
Driving means for reciprocating the cleaning member along the wire electrode;
A load applying means that is provided on the reciprocating movement track and applies a load to the cleaning member in a direction opposite to the moving direction when the cleaning member moved by the driving means passes;
Monitoring means for monitoring current supplied to the driving means;
Identification means for identifying the position of the cleaning member on the track based on the monitoring result of the current by the monitoring means;
A discharge electrode cleaning device comprising: The specifying means specifies the position of the cleaning member based on the current monitoring result and the moving direction of the cleaning member by the driving means.
The discharge electrode cleaning apparatus according to claim 16. On the orbit, a plurality of the load applying means are arranged at predetermined intervals,
The specifying unit compares the waveform of the current as the monitoring result with the interval, and specifies the position of the cleaning member on the track,
The discharge electrode cleaning apparatus according to claim 16 or 17, characterized in that: On the track, a plurality of load applying means are arranged to apply the load to the cleaning member by a preset load amount,
The specifying unit compares the waveform of the current as the monitoring result with the amount of increase in the driving force, and specifies the position of the cleaning member on the track.
The discharge electrode cleaning apparatus according to claim 16 or 17, characterized in that: At least one of the plurality of load applying means is provided in the vicinity of the start position of the reciprocating movement,
The specifying means specifies at least that the position of the cleaning member is the start position;
The discharge electrode cleaning apparatus according to claim 18 or 19, characterized in that At least one of the plurality of load applying means is provided in the vicinity of the reversal position in the reciprocating movement,
The specifying means specifies at least that the position of the cleaning member is the reverse position;
The discharge electrode cleaning apparatus according to claim 18 or 19, characterized in that At least one of the plurality of load applying means is provided in the vicinity of the start position of the reciprocating movement, and at least one of the remaining load applying means is in the vicinity of the reversing position in the reciprocating movement. Provided,
The specifying means identifies and specifies that the cleaning member is located at the start position and the reverse position;
The discharge electrode cleaning apparatus according to claim 18 or 19, characterized in that Control means for controlling the drive means to move the cleaning member by a predetermined distance along the reciprocating trajectory;
The specifying means measures a moving time when the specified distance is moved, and corrects the position of the specified cleaning member based on the monitoring result of the current based on the measured moving time.
The discharge electrode cleaning device according to any one of claims 16 to 22, wherein the device is a discharge electrode cleaning device. Control means for controlling the driving means based on the position of the cleaning member specified by the specifying means to stop the movement of the cleaning member or reverse the moving direction of the cleaning member,
The discharge electrode cleaning device according to any one of claims 16 to 22, wherein the device is a discharge electrode cleaning device. Control means for controlling the drive means based on the position of the cleaning member specified by the specifying means to move the cleaning member to the start position of the reciprocating movement.
The discharge electrode cleaning device according to any one of claims 16 to 22, wherein the device is a discharge electrode cleaning device. The load applying means includes a load applying member provided to contact the cleaning member moved by the driving means and apply the load.
The discharge electrode cleaning apparatus according to any one of claims 16 to 25, wherein: The load applying member is an elastic member that is deformed when contacting the cleaning member.
27. The discharge electrode cleaning apparatus according to claim 26. The elastic member is a leaf spring.
The discharge electrode cleaning apparatus according to claim 27. The elastic member is a member having flexibility.
The discharge electrode cleaning apparatus according to claim 27. The wire electrode constitutes a corona discharger and is provided in a shield member,
The cleaning member has a pad disposed in the shield member and in contact with the wire electrode, and a holding portion that holds the pad at one end and the other end is disposed outside the shield member. And
The load applying means is disposed outside the shield member and contacts the holding portion of the cleaning member.
The discharge electrode cleaning apparatus according to any one of claims 26 to 29, wherein:

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