JP2016218273A - Image formation apparatus - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an image formation apparatus which can use a cleaning member over a long period.SOLUTION: An image formation apparatus comprises: an electrifying wire 414c; a cleaning part 414e which cleans the electrifying wire 414c in accordance with a pressing force applied to the electrifying wire 414c; a tension adjustment part 414d which adjusts the pressing force applied to the electrifying wire 414c with the tension of the electrifying wire 414c on the basis of the number of image formation forming an image in a recording medium from installation of the cleaning part 414e when the cleaning part 414e cleans the electrifying wire 414c; and a number control part 802 which controls the number of times for the cleaning part 414e cleaning the electrifying wire 414c on the basis of the number of image formation. The cleaning part 414e has a cleaning member 454, the pressing force from the electrifying wire 414c to the cleaning member 454 is reduced and the number of times of cleaning of the electrifying wire 414c increases as the number of image formation increases.SELECTED DRAWING: Figure 2

Description

  The present invention relates to an image forming apparatus.

  Conventionally, in an electrophotographic image forming apparatus, a cleaning member that performs cleaning according to a contamination level of a charging wire by adjusting a pressing force applied to the charging wire as a contaminant that adheres to the charging wire is removed. Some have (for example, refer to Patent Document 1).

  In addition, in an image forming apparatus of the same type, there is an apparatus that extends the life of the cleaning member while cleaning the charging wire by changing the location where the cleaning member contacts the charging wire (for example, patents). Reference 2).

JP 2010-85704 A JP 2006-259071 A

  The technique described in Patent Document 1 efficiently cleans the charging wire by using the pressing force applied to the charging wire from the cleaning member, but does not extend the life of the cleaning member.

  The technique described in Patent Document 2 is intended to reduce the local wear of the cleaning member by changing the location where the cleaning member contacts the charging wire, thereby extending the life of the cleaning member. It is not the control which considered the whole use aspect over the period from the installation of the cleaning member to the life of the cleaning member.

  In other words, the conventional techniques as described in Patent Documents 1 and 2 do not take into account the deterioration of the cleaning member over time. Therefore, in the above prior art, since the deterioration of the cleaning member over time is unavoidable, the cleaning member may not be used for a long time.

  SUMMARY An advantage of some aspects of the invention is that it provides an image forming apparatus in which a cleaning member can be used over a long period of time.

  In order to achieve the above object, an image forming apparatus according to the present invention is an image forming apparatus that forms an image by an electrophotographic method, in accordance with a charging wire for charging a photosensitive drum and a pressing force applied to the charging wire. When the cleaning unit cleans the charging wire and the cleaning unit cleans the charging wire, an image is formed on the recording medium after the photosensitive drum, the charging wire, and the cleaning unit are installed. A tension adjusting unit that adjusts the pressing force applied to the charging wire based on the number of image formations, and a cleaning number of times that the cleaning unit cleans the charging wire based on the number of image formations. And a cleaning member that is deformed by the pressing force given by the tension of the charging wire, and the number of times of image formation is As to pressure, the pressing force is reduced to the cleaning member from the charging wire, the cleaning times of the charging wire is intended to be increased.

  According to this image forming apparatus, since the cleaning ability of the cleaning member can be maintained over a long period of time, and the surface state of the charging wire can be maintained in a state suitable for charging, the cleaning member can be used over a long period of time. Can do.

  In the image forming apparatus according to the present invention, the tension adjusting unit reduces the tension of the charging wire as the number of times of image formation increases, and the cleaning unit reduces the tension of the charging wire. It is preferable that the amount of biting of the charging wire due to deformation of the cleaning member is small.

  According to this image forming apparatus, since the amount of deterioration of the cleaning member with time can be suppressed to a constant amount, the life of the cleaning member can be extended.

  In the image forming apparatus according to the present invention, the number control unit increases the number of cleanings of the charging wire as the number of times of image formation increases, and the number of cleanings of the charging wire is determined by the cleaning unit. It is preferable that one reciprocation of the wire is performed once.

  According to this image forming apparatus, although the dirt removed from the charging wire by one cleaning is reduced, the cleaning unit increases the number of times the cleaning wire reciprocates the charging wire correspondingly, so the cleaning member as a whole The cleaning ability can be maintained.

  The image forming apparatus according to the present invention further includes a position control unit that controls a position of the cleaning unit, and the position control unit does not contact the charging wire when the cleaning unit does not clean the charging wire. When the cleaning unit is controlled to the release position, and the cleaning unit cleans the charging wire, the cleaning unit is controlled to the cleaning position to be in contact with the charging wire, and the charging controlled by the number control unit is performed. Based on the number of wire cleanings, the cleaning unit is reciprocated along the charging wire, and the tension adjusting unit is configured to charge the charging wire when the cleaning unit is in the release position and cleaning of the charging wire is started. Increase or decrease the tension of the wire, and maintain the tension of the charging wire when the cleaning unit is at the cleaning position and the cleaning of the charging wire is continued. It is preferable.

  According to this image forming apparatus, the cleaning member can be prevented from aging, and therefore the life of the cleaning member can be extended.

  In the image forming apparatus according to the aspect of the invention, the cleaning member may include a contact surface that contacts the charging wire, and the cleaning unit may include a first surface provided with the first surface of the contact surfaces. A support member and a second support member provided with a second surface of the contact surfaces; and the position control unit is configured to connect the charging wire by the first surface and the second surface. When the charging wire is sandwiched to clean the charging wire, it is preferable that the charging wire is sandwiched in a V shape.

  According to this image forming apparatus, since the necessary number of cleanings can be adjusted according to the amount of biting, the total number of cleanings of the cleaning member can be adjusted.

  In the image forming apparatus according to the aspect of the invention, the tension adjusting unit may include the charging wire in a first stage from the installation of the photosensitive drum, the charging wire, and the cleaning unit to a preset time. In the second stage from the first stage to the life of the cleaning member, the tension of the charging wire is reduced, and the number control unit is configured to reduce the tension in the first stage. The charging wire cleaning frequency is set to a preset first frequency, and in the second stage, the charging wire cleaning frequency is set to a second frequency greater than the first frequency. preferable.

  According to this image forming apparatus, since the total number of cleanings of the cleaning member can be reduced while maintaining the overall cleaning capability, the life of the cleaning member can be extended.

  In the image forming apparatus according to the aspect of the invention, it is preferable that the tension adjusting unit is disposed outside the effective charging range of the photosensitive drum and adjusts the position of the charging wire.

  According to this image forming apparatus, it is possible to provide a configuration for extending the life of the cleaning member without hindering image formation by the photosensitive drum.

The image forming apparatus according to the present invention may further include an image forming unit that forms an image on the recording medium, wherein the charging wire is cleaned by the cleaning unit, and the cleaning unit is in the release position. In this case, it is preferable to form an image on the recording medium.

  According to this image forming apparatus, the surface state of the charging wire can be maintained in a state suitable for charging and the life of the cleaning member can be extended. Replacement costs can be reduced.

  In the image forming apparatus according to the aspect of the invention, it is preferable that the number control unit sets the number of image formations to a preset initial value when the cleaning unit is replaced.

  According to this image forming apparatus, the number of cleanings of the charging wire and the pressing force applied to the charging wire can be controlled in consideration of the life of the cleaning unit. The pressing force can be controlled appropriately, and the overall image forming cost can be reduced.

  According to the present invention, since the cleaning ability of the cleaning member can be maintained over a long period of time, and the surface state of the charging wire can be maintained in a state suitable for charging, the cleaning member can be used over a long period of time. .

1 is a diagram illustrating an example of an overall configuration of an image forming apparatus 1 according to an embodiment. 3 is a diagram illustrating an example of a configuration of a charging device 414. FIG. 4 is a block diagram illustrating an example of an effective charging range 1000 of the photosensitive drum 413. FIG. It is a figure which shows an example of the positional relationship of the cleaning part 414e and the photosensitive drum 413 when the release position of the cleaning part 414e is seen from the side. It is a figure which shows an example of the positional relationship of the cleaning part 414e and the photosensitive drum 413 when the cancellation | release position of the cleaning part 414e is seen from the top. It is a figure which shows an example of the positional relationship of the cleaning part 414e and the photosensitive drum 413 when the cleaning position of the cleaning part 414e is seen from the side. It is a figure which shows an example of the positional relationship of the cleaning part 414e and the photosensitive drum 413 when the cleaning position of the cleaning part 414e is seen from the top. It is a figure which shows the transition of the position of the charging wire 414c. 2 is a diagram illustrating an example of a functional configuration of the image forming apparatus 1. FIG. 4 is a flowchart for explaining an operation example of the image forming apparatus 1. It is a figure which shows the relationship between the slack of the cleaning member 454, and the lifetime of the cleaning member 454. FIG.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings, but the present invention is not limited to the following embodiments.

  FIG. 1 is a diagram illustrating an example of the overall configuration of an image forming apparatus 1 according to the present embodiment. As shown in FIG. 1, the image forming apparatus 1 uses an electrophotographic process technology and is an intermediate transfer type color image forming apparatus. In the image forming apparatus 1, photosensitive drums 413 corresponding to four colors of Y (yellow), M (magenta), C (cyan), and K (black) are arranged in series in the running direction (vertical direction) of the intermediate transfer belt 421. Has been. The image forming apparatus 1 employs a vertical tandem system in which each color toner image is sequentially transferred onto the intermediate transfer belt 421.

  That is, the image forming apparatus 1 primarily transfers the YMCK color toner images formed on the photosensitive drum 413 to the intermediate transfer belt 421. The image forming apparatus 1 forms an image on the sheet P by superimposing four color toner images on the intermediate transfer belt 421 and then performing secondary transfer onto the sheet P.

  As shown in FIG. 1, the image forming apparatus 1 includes a document reading device SC, an operation display unit 20, an image forming unit 40, a conveyance path 50, a fixing unit 60, a control unit 80, and the like. The control unit 80 includes an image processing unit 810 and the like.

  The control unit 80 is mainly configured by a CPU, ROM, RAM, and an I / O interface (not shown), and the CPU reads various programs corresponding to processing contents from the ROM or a storage unit (not shown), and the RAM And the respective operations of the blocks of the image forming apparatus 1, the document reading device SC, the operation display unit 20, and the like are controlled by cooperating with the developed various programs.

  That is, the control unit 80 controls the operation of the image forming apparatus 1 and can be realized by a microcomputer mainly composed of a CPU, a ROM, a RAM, and an I / O interface (not shown).

  Specifically, when the control unit 80 executes a predetermined control program, in addition to the image processing unit 810, a tension control unit 801, a number control unit 802, a position control unit 803, and a timing unit, which will be described later in detail. Functions including 805 are realized.

  The operation display unit 20 is configured by, for example, a liquid crystal display (LCD) with a touch panel, and functions as a display unit and an operation unit (not shown).

  The display unit displays various operation screens, operation states of functions, and the like based on display control signals input from the control unit 80. The operation unit includes various operation keys such as a numeric keypad and a start key. The operation unit outputs an operation signal to the control unit 80 by accepting various input operations by the user. The user can perform image quality setting by operating the operation display unit 20. Further, the user can perform settings relating to image formation such as magnification setting, application setting, output setting, and paper setting by operating the operation display unit 20. Further, the user can issue a paper conveyance instruction by operating the operation display unit 20.

  For example, the paper transport unit 70 transports the paper P along the transport path 50 of the paper P. The paper P is stored in the paper supply tray 71, and the paper P stored in the paper supply tray 71 is taken in by the paper supply unit 72 and sent out to the transport path 50.

  The conveyance path 50 includes a plurality of conveyance roller units including an intermediate conveyance roller, a loop roller 53, and a registration roller 54. The conveyance path 50 conveys the paper P fed from the paper feeding unit 72 in the order of the image forming unit 40, the fixing unit 60, and the paper discharge roller 58.

  The document reader SC scans and exposes an image of the document with the optical system of the scanning exposure device, reads the reflected light with a line image sensor, and obtains an image signal. The image signal is subjected to processing such as A / D conversion, shading correction, and compression, and then input to the control unit 80 as a read value of the image. Note that the input image data input to the control unit 80 is not limited to the data read by the document reading device SC, but is received from, for example, a personal computer connected to the image forming device 1 or another image forming device 1. Alternatively, it may be read from a portable recording medium such as a semiconductor memory.

  The image processing unit 810 performs digital image processing on input image data according to initial settings or user settings. For example, the image processing unit 810 performs gradation correction based on gradation correction data configured as a gradation correction table. The image processing unit 810 performs various correction processes such as color correction and shading correction, or compression processing on the input image data. The image forming unit 40 is controlled based on the image data subjected to these processes.

  The image forming unit 40 is an image forming unit for forming an image with each color toner of the Y component, the M component, the C component, and the K component based on the image data subjected to various processes in the image processing unit 810. 41, an intermediate transfer unit 42, and the like, and transfers the toner image onto the paper P.

  The image forming unit 41 includes four image forming units 41Y, 41M, 41C, and 41K for Y component, M component, C component, and K component. Since each of the image forming units 41Y, 41M, 41C, and 41K has similar constituent elements, common constituent elements are denoted by the same reference numerals, and description thereof is omitted. For example, in FIG. 1, reference numerals are given only to the constituent elements of the image forming unit 41Y for Y component, and the reference numerals of constituent elements of the other image forming units 41M, 41C, 41K are omitted.

  The image forming unit 41 includes an exposure device 411, a developing device 412, a photosensitive drum 413, a charging device 414, a drum cleaning device 415, and the like.

  The photosensitive drum 413 is, for example, a negative electrode in which an undercoat layer (UCL), a charge generation layer (CGL), and a charge transport layer (CTL) are sequentially laminated on the peripheral surface of an aluminum conductive cylindrical body (aluminum tube). It is a charge-type organic photoreceptor (OPC).

  The charge generation layer is made of an organic semiconductor in which a charge generation material (for example, phthalocyanine pigment) is dispersed in a resin binder (for example, polycarbonate), and is exposed by the exposure device 411 to generate a pair of positive charges and negative charges.

  The charge transport layer consists of a hole transport material (electron donating nitrogen-containing compound) dispersed in a resin binder (for example, polycarbonate resin), and transports positive charges generated in the charge generation layer to the surface of the charge transport layer. To do.

  The charging device 414 is constituted by, for example, a corona discharge generator such as a scorotron charging device or a corotron charging device. The charging device 414 uniformly charges the surface of the photosensitive drum 413 to a negative polarity by corona discharge.

  The exposure apparatus 411 includes, for example, an LED array in which a plurality of light emitting diodes (LEDs) are linearly arranged, an LPH driving unit (driver IC) for driving each LED, and a photosensitive drum that emits light emitted from the LED array An LED print head having a lens array to be imaged on 413 is formed. One LED in the LED array corresponds to one dot of the image. When the control unit 80 controls the LPH driving unit, a predetermined driving current flows through the LED array, and a specific LED emits light.

  The exposure device 411 irradiates the photosensitive drum 413 with light corresponding to the image of each color component. The positive charge generated in the charge generation layer of the photosensitive drum 413 is transported to the surface of the charge transport layer, so that the surface charge (negative charge) of the photosensitive drum 413 is neutralized. Thereby, an electrostatic latent image of each color component is formed on the surface of the photosensitive drum 413 due to a potential difference from the surroundings.

  The developing device 412 contains a developer for each color component (for example, a two-component developer composed of toner and a magnetic carrier). The developing device 412 makes the toner of each color component adhere to the surface of the photosensitive drum 413, thereby visualizing the electrostatic latent image and forming a toner image. Specifically, a developing bias voltage is applied to the developer carrying member (developing roller), and the charged toner on the developer carrying member is transferred to the surface of the photosensitive drum 413 due to a potential difference between the photosensitive drum 413 and the developer carrying member. Move to the exposed area and adhere.

  The drum cleaning device 415 includes a drum cleaning blade that is in sliding contact with the surface of the photosensitive drum 413. The drum cleaning device 415 removes transfer residual toner remaining on the surface of the photosensitive drum 413 after the primary transfer.

  The intermediate transfer unit 42 includes an intermediate transfer belt 421, a primary transfer roller 422, a plurality of support rollers 423, a secondary transfer roller 424, a belt cleaning device 426, and the like.

  The intermediate transfer belt 421 is an endless belt, and is stretched in a loop shape by a plurality of support rollers 423. At least one of the plurality of support rollers 423 is configured by a driving roller, and the other is configured by a driven roller. For example, it is preferable that the support roller 423 disposed downstream of the K component primary transfer roller 422 in the belt traveling direction is a drive roller. As the driving roller rotates, the intermediate transfer belt 421 travels in the direction of arrow A at a constant speed.

  The primary transfer roller 422 is disposed on the inner peripheral surface side of the intermediate transfer belt 421 so as to face the photosensitive drum 413 of each color component. The primary transfer roller 422 is pressed against the photosensitive drum 413 with the intermediate transfer belt 421 interposed therebetween, whereby a primary transfer nip for transferring a toner image from the photosensitive drum 413 to the intermediate transfer belt 421 is formed.

  The secondary transfer roller 424 is disposed on the outer peripheral surface side of the intermediate transfer belt 421 so as to face one of the plurality of support rollers 423. The support roller 423 arranged to face the intermediate transfer belt 421 is called a backup roller. The secondary transfer roller 424 is pressed against the backup roller with the intermediate transfer belt 421 interposed therebetween, thereby forming a secondary transfer nip for transferring the toner image from the intermediate transfer belt 421 to the paper P.

  When the intermediate transfer belt 421 passes through the primary transfer nip, the toner image on the photosensitive drum 413 is primarily transferred onto the intermediate transfer belt 421 in order. Specifically, by applying a primary transfer bias to the primary transfer roller 422 and applying a charge having a polarity opposite to that of the toner to the back side of the intermediate transfer belt 421, that is, the side in contact with the primary transfer roller 422, the toner image Is electrostatically transferred to the intermediate transfer belt 421.

  Thereafter, when the paper P passes through the secondary transfer nip, the toner image on the intermediate transfer belt 421 is secondarily transferred to the paper P. Specifically, a secondary transfer bias is applied to the secondary transfer roller 424, and a charge having a polarity opposite to that of the toner is applied to the back side of the paper P, that is, the side in contact with the secondary transfer roller 424. The image is electrostatically transferred to the paper P. The sheet P on which the toner image is transferred is conveyed toward the fixing unit 60.

  The belt cleaning device 426 includes a belt cleaning blade that is in sliding contact with the surface of the intermediate transfer belt 421. The belt cleaning device 426 removes transfer residual toner remaining on the surface of the intermediate transfer belt 421 after the secondary transfer.

  In the intermediate transfer unit 42, instead of the secondary transfer roller 424, a secondary transfer belt (not shown) is looped around a plurality of support rollers 423 including the secondary transfer roller 424, so-called A belt-type secondary transfer unit may be employed.

  The fixing unit 60 includes a fixing roller 601, a pressure roller 602, a heating unit 603, and the like, and fixes the toner image transferred by the image forming unit 40 onto the paper P. Specifically, in the fixing unit 60, a fixing roller 601 and a pressure roller 602 are pressed against each other to form a fixing nip. In the fixing unit 60, the heating unit 603 heats the fixing roller 601. The fixing unit 60 fixes the transferred toner image on the paper P through the action of pressure by the pressure roller 602 and heat of the fixing roller 601. The paper P fixed by the fixing unit 60 is discharged to the outside by the paper discharge roller 58.

  When image formation is performed also on the back surface of the paper P, the paper P is transported to the refeed transport path 52 by the switching gate 51 after image formation on the front surface of the paper P is completed. In the refeed conveyance path 52, the rear end of the conveyed paper P is nipped by the reverse roller 55 and then reversely fed to reverse the front and back of the paper P. The paper P whose front and back are reversed is transported by a plurality of transport rollers, and is joined to a transport path 50 on the upstream side of the transfer position in order to provide image formation on the other surface.

  Next, details of the photosensitive drum 413 and the charging device 414 will be described in order with reference to FIGS. FIG. 2 is a diagram illustrating an example of the configuration of the charging device 414. As shown in FIG. 2, the charging device 414 is disposed below the photosensitive drum 413. The charging device 414 includes a charging block 414a, a charging wire 414c, a tension adjusting unit 414d, a cleaning unit 414e, and the like. The charging block 414a supports the charging wire 414c and supplies power to the charging wire 414c. The charging wire 414c is for corona discharge by power feeding from the charging block 414a, and charges the photosensitive drum 413. The cleaning unit 414e cleans the charging wire 414c, and the cleaning capability of the charging wire 414c increases or decreases according to the pressing force applied to the charging wire 414c.

  The tension adjusting unit 414d adjusts the tension of the charging wire 414c, and is composed of, for example, a cam. The tension adjusting unit 414d adjusts the pressing force applied to the charging wire 414c by the tension of the charging wire 414c. For example, the tension adjusting unit 414d increases the pressing force applied to the charging wire 414c by increasing the tension of the charging wire 414c. The tension adjusting unit 414d reduces the pressing force applied to the charging wire 414c by reducing the tension of the charging wire 414c.

  More specifically, since the tension adjusting unit 414d is composed of a cam, the tension of the charging wire 414c increases when the charging wire 414c is pushed down by the cam, and the charging wire 414c is released by releasing the cam. Returning to the original position, the tension of the charging wire 414c is reduced. That is, the tension adjusting unit 414d adjusts the position of the charging wire 414c by adjusting the tension of the charging wire 414c.

  Further, the pressing force applied to the charging wire 414c is determined when the cleaning unit 414e cleans the charging wire 414c, after the photosensitive drum 413, the charging wire 414c, and the cleaning unit 414e are installed, specifically, the recording medium. It may be determined based on the number of image formations on which the image is formed on the paper P.

  Next, the arrangement configuration of the tension adjusting unit 414d will be described with reference to FIG. FIG. 3 is a block diagram showing an example of the effective charging range 1000 of the photosensitive drum 413. As shown in FIG. 3, the tension adjusting unit 414 d is disposed outside the effective charging range 1000 of the photosensitive drum 413. The effective charging range 1000 is set in a region from a part of the photosensitive drum 413 to the charging wire 414c. For example, a charging control plate (not shown), a side plate made of SUS, a back plate made of SUS, and the like. The effective charging range 1000 is set by being provided between the photosensitive drum 413 and the charging wire 414c.

  Therefore, the tension adjusting unit 414d is disposed between the photosensitive drum 413 and the charging wire 414c, and is provided at a position where the charging of the photosensitive drum 413 is not hindered. Although illustration is omitted, since the moving mechanism of the cleaning unit 414e is provided on the back plate side, the tension adjusting unit 414d is not disposed on the back plate side.

  Next, details of the cleaning unit 414e will be described with reference to FIGS. FIG. 4 is a diagram illustrating an example of a positional relationship between the cleaning unit 414e and the photosensitive drum 413 when the release position of the cleaning unit 414e is viewed from the side. As shown in FIG. 4, the cleaning part 414e includes a pedestal part 451, a first support member 453a, a second support member 453b, a cleaning member 454a, a cleaning member 454b, and the like. Note that the cleaning member 454a and the cleaning member 454b are collectively referred to as a cleaning member 454.

  The cleaning member 454a and the cleaning member 454b are made of, for example, a fibrous fabric, and are deformed by a pressing force applied by the tension of the charging wire 414c. The amount of biting of the charging wire 414c varies between the cleaning member 454a and the cleaning member 454b according to the tension of the charging wire 414c. For example, as the tension of the charging wire 414c increases, the amount of biting of the charging wire 414c increases in the cleaning member 454a and the cleaning member 454b. Further, as the tension of the charging wire 414c decreases, the cleaning member 454a and the cleaning member 454b reduce the amount of biting of the charging wire 414c.

  The cleaning member 454a and the cleaning member 454b can clean the charging wire 414c by contacting the charging wire 414c, and a contact surface that contacts the charging wire 414c is formed. For example, among such contact surfaces, the first surface is formed on the cleaning member 454a, and the second surface is formed on the cleaning member 454b.

  The first support member 453a supports the cleaning member 454a and is provided with a first surface. The second support member 453b supports the cleaning member 454b and is provided with a second surface. The first support member 453a and the second support member 453b are configured so as to stand upright while being inclined from the pedestal portion 451.

  Here, the first support member 453a and the second support member 453b are in the most distant positional relationship when the charging wire 414c is at the initial position C, and gradually approach as the charging wire 414c moves toward the moving direction. It only has to be in a relationship.

  Therefore, since the cleaning member 454a and the cleaning member 454b need only be provided in an inclined state, it is necessary that each of the first support member 453a and the second support member 453b be in an inclined state. Absent. For example, the location where the cleaning member 454a is provided in the first support member 453a only needs to be inclined. The same applies to the second support member 453b.

  Each of the first support member 453a, the second support member 453b, and the pedestal portion 451 is made of, for example, resin, and may be integrally formed, and each of them is configured to be connected. It may be a thing.

  Next, the positional relationship among the cleaning member 454, the first support member 453a, the second support member 453b, and the charging wire 414c will be described with reference to FIG. FIG. 5 is a diagram illustrating an example of a positional relationship between the cleaning unit 414e and the photosensitive drum 413 when the release position of the cleaning unit 414e is viewed from above.

  As shown in FIG. 5, when the cleaning unit 414e is in the release position, the cleaning member 454a and the cleaning member 454b are in a positional relationship that does not contact the charging wire 414c. Therefore, even if the cleaning unit 414e is moved along the charging wire 414c in this state, the charging wire 414c cannot be cleaned.

  Next, a state where the charging wire 414c is pushed down by the tension adjusting unit 414d will be described with reference to FIG. FIG. 6 is a diagram illustrating an example of a positional relationship between the cleaning unit 414e and the photosensitive drum 413 when the cleaning position of the cleaning unit 414e is viewed from the side. As shown in FIG. 6, the charging wire 414 c is located away from the initial position C, and is pushed downward from the initial position C. Therefore, since the tension of the charging wire 414c is increasing, the pressing force applied to the charging wire 414c is increasing.

  Note that the initial position C is a default position of the charging wire 414c when the downward pressing force is not applied to the charging wire 414c.

  Further, when the cleaning unit 414e is at the cleaning position, the cleaning member 454a and the cleaning member 454b are in a positional relationship in contact with the charging wire 414c. Therefore, since the cleaning member 454 is in a positional relationship that can be deformed by the pressing force applied by the tension of the charging wire 414c, the amount of biting of the charging wire 414c due to the deformation of the cleaning member 454 is large.

  Next, the positional relationship among the cleaning member 454, the first support member 453a, the second support member 453b, and the charging wire 414c will be described with reference to FIG. FIG. 7 is a diagram illustrating an example of a positional relationship between the cleaning unit 414e and the photosensitive drum 413 when the cleaning position of the cleaning unit 414e is viewed from above.

  As shown in FIG. 7, when the cleaning part 414e exists in a cleaning position, the cleaning member 454a and the cleaning member 454b are in the positional relationship which contacts the charging wire 414c. Furthermore, when the cleaning unit 414e continues to clean the charging wire 414c, the tension adjusting unit 414d maintains the tension of the charging wire 414c. Therefore, the cleaning unit 414e can clean the charging wire 414c when it is moved along the charging wire 414c in this state.

  Next, a series of operations until the cleaning unit 414e shifts from the state at the release position to the state at the cleaning position and returns from the state at the cleaning position to the state at the release position will be described with reference to FIG. FIG. 8 is a diagram illustrating a change in the position of the charging wire 414c.

  In the first state D1, the cleaning unit 414e is at the release position, and the charging wire 414c remains at the initial position C. In the case of the first state D1, the cleaning unit 414e cannot clean the charging wire 414c.

  Next, in the second state D2, the cleaning unit 414e is in the release position, and the charging wire 414c is in a position away from the initial position C. That is, in a state where the cleaning unit 414e is in the release position, the tension adjusting unit 414d pushes down the charging wire 414c and increases the tension of the charging wire 414c. In the case of the second state D2, the cleaning unit 414e cannot clean the charging wire 414c.

  Next, in the third state D3, the cleaning unit 414e is at the cleaning position, and the charging wire 414c remains at a position away from the initial position C. In the case of the third state D3, the cleaning unit 414e can clean the charging wire 414c.

  Next, in the fourth state D4, the cleaning unit 414e is at the release position, and the charging wire 414c remains at the initial position C. In the case of the fourth state D4, the cleaning unit 414e cannot clean the charging wire 414c.

  Thus, when the cleaning unit 414e cleans the charging wire 414c, the cleaning unit 414e and the charging wire 414c are respectively moved to predetermined positions.

  Next, details of a functional configuration example of the image forming apparatus 1 will be described. A part of the description of the functional configuration described above is omitted. FIG. 9 is a diagram illustrating an example of a functional configuration of the image forming apparatus 1. As illustrated in FIG. 9, the control unit 80 includes a tension control unit 801, a number control unit 802, a position control unit 803, and a time measuring unit 805 in addition to the image processing unit 810.

  When the cleaning unit 414e cleans the charging wire 414c, the tension control unit 801 forms an image on a recording medium such as paper P after the photosensitive drum 413, the charging wire 414c, and the cleaning unit 414e are installed. Based on the number of times, the tension adjusting unit 414d is controlled so that the pressing force applied to the charging wire 414c is adjusted by the tension of the charging wire 414c.

  That is, when the cleaning unit 414e cleans the charging wire 414c, the tension adjusting unit 414d forms an image on the recording medium, for example, the paper P, after the photosensitive drum 413, the charging wire 414c, and the cleaning unit 414e are installed. Based on the number of image formations, the pressing force applied to the charging wire 414c is adjusted by the tension of the charging wire 414c.

  Specifically, the tension adjusting unit 414d reduces the tension of the charging wire 414c as the number of times of image formation described above increases under the control of the tension control unit 801. The tension adjusting unit 414d is configured to increase or decrease the tension of the charging wire 414c when the cleaning unit 414e is at the release position and cleaning of the charging wire 414c is started under the control of the tension control unit 801. The tension adjustment unit 414d maintains the tension of the charging wire 414c when the cleaning unit 414e is at the cleaning position and the cleaning of the charging wire 414c is continued by the control of the tension control unit 801.

  More specifically, the tension adjusting unit 414d is controlled by the tension control unit 801 in the first stage from the installation of the photosensitive drum 413, the charging wire 414c, and the cleaning unit 414e to a preset time, that is, In the initial cleaning stage G1 described later, the tension of the charging wire 414c is increased, and in the second stage from the initial cleaning stage G1 to the life of the cleaning member 454, that is, in the final cleaning stage G2 described later, the tension of the charging wire 414c is decreased. .

  Here, in the initial cleaning G1 described later, the tension of the charging wire 414c may be increased to a preset upper limit value to maximize the amount of biting of the charging wire 414c. In the cleaning end stage G2, which will be described later, the tension of the charging wire 414c may be reduced to a preset lower limit value, that is, a default setting, and the amount of biting of the charging wire 414c may be minimized.

  The number control unit 802 controls the number of times the cleaning unit 414e cleans the charging wire 414c based on the number of image formations described above.

  Specifically, the number control unit 802 increases the number of cleanings of the charging wire 414c as the number of image formations described above increases. Here, the number of cleanings of the charging wire 414c is such that the cleaning unit 414e reciprocates the charging wire 414c once.

  More specifically, the number control unit 802 sets the number of cleanings of the charging wire 414c to a preset first number in the initial cleaning G1 described later. Further, the number control unit 802 sets the number of cleanings of the charging wire 414c to a second number larger than the first number in the cleaning end stage G2 to be described later. When the cleaning unit 414e is replaced, the number control unit 802 sets the number of image formations described above to a preset initial value, for example, zero.

  The position control unit 803 controls the position of the cleaning unit 414e. Specifically, when the cleaning unit 414e does not clean the charging wire 414c, the position control unit 803 controls the cleaning unit 414e to a release position that does not contact the charging wire 414c. When the cleaning unit 414e cleans the charging wire 414c, the position control unit 803 controls the cleaning unit 414e to a cleaning position where the cleaning unit 414e contacts the charging wire 414c.

  More specifically, the position control unit 803 cleans the charging wire 414c by sandwiching the charging wire 414c between the first surface formed on the cleaning member 454a and the second surface formed on the cleaning member 454b. At this time, the shape sandwiching the charging wire 414c is changed to a V-shape. For example, the position controller 803 rotates the first support member 453a and the second support member 453b by rotating the pedestal 451 with an actuator (not shown), and the cleaning member 454a and the cleaning member 454b. May be controlled to a position in contact with the charging wire 414c.

  The timer 805 counts the number of image formations described above. Specifically, the timing unit 805 counts the number of image formations based on the image formation command generated by the image processing unit 810.

  In other words, as the number of image formations described above increases, the cleaning unit 414e reduces the pressing force from the charging wire 414c to the cleaning member 454, and increases the number of cleanings of the charging wire 414c. In addition, the cleaning unit 414e has a smaller bite amount of the charging wire 414c due to the deformation of the cleaning member 454 as the tension of the charging wire 414c is reduced.

  The image forming unit 40 forms an image on a recording medium, for example, paper P, when the charging wire 414c is cleaned by the cleaning unit 414e and the cleaning unit 414e is in the release position.

  Next, an example of the cleaning operation in consideration of the deterioration over time of the cleaning member 454 will be described with reference to FIG. FIG. 10 is a flowchart for explaining an operation example of the image forming apparatus 1.

  In step S11, the image processing unit 810 determines whether printing has ended. When printing is completed, the process proceeds to step S12. On the other hand, if printing has not been completed, the printer waits until printing is completed.

  In step S12, the position control unit 803 determines whether or not the cleaning member 454 exists at the release position. When the cleaning member 454 exists in the release position, the process proceeds to step S13. On the other hand, when the cleaning member 454 is not present at the release position, the standby state is maintained until the cleaning member 454 is controlled to the release position.

  In step S13, the tension control unit 801 confirms the number of prints, that is, the number of image formations described above. In step S14, the tension control unit 801 instructs the position of the charging wire 414c based on the number of printed sheets.

  In step S15, the tension control unit 801 adjusts the position of the charging wire 414c by controlling the position of the tension adjusting unit 414d, specifically the cam.

  Specifically, the tension control unit 801 causes the tension adjustment unit 414d to adjust the position of the charging wire 414c based on the number of image formations described above.

  In step S16, the number control unit 802 instructs the number of cleanings based on the number of prints, that is, the number of image formations described above.

  In step S17, the cleaning unit 414e starts a cleaning operation. Specifically, the position control unit 803 reciprocates the cleaning unit 414e along the charging wire 414c based on the number of cleanings of the charging wire 414c controlled by the number control unit 802.

  In step S18, the position control unit 803 determines whether or not the cleaning member 454 exists at the release position. When the cleaning member 454 exists in the release position, the process proceeds to step S19. On the other hand, when the cleaning member 454 is not present at the release position, the standby state is maintained until the cleaning member 454 is controlled to the release position.

  In step S19, the tension control unit 801 releases the tension adjusting unit 414d, specifically the cam. As a result, the charging wire 414c is returned to the initial position C.

  In step S20, the image processing unit 810 starts printing. Specifically, when the charging wire 414c is cleaned by the cleaning unit 414e, the cleaning unit 414e is in the release position, and the charging wire 414c is returned to the initial position C, the image processing unit 810 detects that the image forming unit 40 An instruction to form an image is issued.

  FIG. 11 is a diagram illustrating the relationship between the sag of the cleaning member 454 and the life of the cleaning member 454. In FIG. 11, a diagram K shows a change in characteristics when the position of the charging wire 414c and the number of cleanings are variable. A diagram J shows a change in characteristics when the position of the charging wire 414c and the number of cleanings are constant. A threshold E indicates a durable NG line of the cleaning member 454. The threshold value F indicates an NG line due to the sag of the charging wire 414c. The initial cleaning stage G1 indicates a first stage from when the charging wire 414c and the cleaning unit 414e are installed to a preset time. The cleaning end stage G2 indicates the second stage from the first stage to the life of the cleaning member 454.

  In the diagram J, the lifetime of the cleaning member 454 is L1. On the other hand, in the diagram K, the lifetime of the cleaning member 454 is L2. L2 indicates that the lifetime of the cleaning member 454 is longer than that of L1. Specifically, in the case of the diagram K, the cleaning number of the charging wire 414c is set to a first preset number in the initial cleaning stage G1, and the cleaning number of the charging wire 414c is set to the first number in the final cleaning stage G2. It is set to a second number greater than the number of times.

  In the initial cleaning stage G1, as described above, since the amount of biting of the charging wire 414c is increased, the cleaning capability of the cleaning member 454 is maintained even if the number of times of cleaning is reduced accordingly.

  In the final cleaning stage G2, as described above, since the amount of biting of the charging wire 414c is reduced, the cleaning capability of the cleaning member 454 is maintained by increasing the number of cleanings accordingly.

  Therefore, the necessary number of cleanings in the initial cleaning stage G1 is suppressed, and the total number of cleanings of the cleaning member 454 from the initial cleaning stage G1 to the final cleaning stage G2 is reduced. As a result, the life of the cleaning member 454 is extended.

  As described above, when the image forming apparatus 1 forms an image by the electrophotographic method, the photosensitive drum 413 is charged by using the charging device 414, particularly the charging wire 414c. Therefore, as the charging wire 414c is used, dirt adheres to it. Therefore, the charging wire 414c is cleaned by the cleaning member 454. Therefore, the charging wire 414c maintains a surface state suitable for charging, so that the image quality of the image formed by the photosensitive drum 413 is also maintained.

  However, since the cleaning member 454 deteriorates as it is used, the cleaning ability for cleaning dirt adhering to the charging wire 414c gradually decreases. As a result, the charging wire 414c may not be partially removed of dirt, and the surface state suitable for charging may not be maintained. If the charging wire 414c charges the photosensitive drum 413 in this state, the image quality of the image formed by the photosensitive drum 413 cannot be maintained.

  In this case, if the cleaning member 454 is frequently replaced, it is possible to maintain a high cleaning capability of the cleaning member 454, but the replacement cost becomes expensive. Therefore, it is desirable that the cleaning unit 414e including the cleaning member 454 maintain the cleaning capability of the cleaning member 454 for a long period of time.

  Therefore, as the number of image formations on the recording medium, eg, paper P, increases, the pressing force applied to the charging wire 414c is reduced. That is, as the number of times of image formation increases, the pressing force from the charging wire 414c to the cleaning member 454 is reduced, so that the frictional force between the charging wire 414c and the cleaning member 454 is reduced. Therefore, although the cleaning member 454 gradually sags as it is used, the frictional force generated between the cleaning member 454 and the charging wire 414c is reduced, so that the life can be extended.

  However, reducing the frictional force generated between the cleaning member 454 and the charging wire 414c reduces the cleaning ability of the cleaning member 454. Therefore, the number of cleanings of the charging wire 414c by the cleaning member 454 is increased by the amount by which the frictional force generated between the cleaning member 454 and the charging wire 414c is reduced. Specifically, as the image formation increases, the number of cleanings of the charging wire 414c by the cleaning member 454 is increased. As a result, the amount of reduction in the frictional force generated between the cleaning member 454 and the charging wire 414c is compensated by the increase in the number of cleanings of the charging wire 414c by the cleaning member 454, so that the overall cleaning capability is maintained. The Rukoto.

  In other words, the cleaning unit 414e including the cleaning member 454 reduces the pressing force applied to the charging wire 414c and increases the number of cleanings of the charging wire 414c as the number of times of image formation increases. Since the cleaning capability of the cleaning member 454 can be maintained and the surface state of the charging wire 414c can be maintained in a state suitable for charging, the cleaning member 454 can be used for a long period of time.

  Further, in the image forming apparatus 1, as the tension of the charging wire 414c is reduced, the amount of biting of the charging wire 414c into the cleaning unit 414e due to the deformation of the cleaning member 454 decreases. Therefore, as the charging wire 414c is cleaned, the amount of deformation of the cleaning member 454 gradually decreases, so that the damage to the cleaning member 454 due to the deformation of the cleaning member 454 decreases. Thereby, the amount of deterioration over time of the cleaning member 454 can be suppressed to a constant amount. Therefore, the life of the cleaning member 454 can be extended.

  Further, as described above, the image forming apparatus 1 increases the number of cleanings of the charging wire 414c as the number of image formations increases. Here, the number of cleanings of the charging wire 414c is such that the cleaning unit 414e reciprocates the charging wire 414c once.

  Therefore, as the number of image formation increases, the image forming apparatus 1 increases the number of times the cleaning unit 414e reciprocates the charging wire 414c as much as the pressing force applied to the charging wire 414c is reduced. Therefore, although the dirt removed from the charging wire 414c by the cleaning per time is reduced, the number of times the cleaning unit 414e reciprocates the charging wire 414c is increased correspondingly, so that the cleaning member 454 is cleaned as a whole. Ability can be maintained.

  Further, when the cleaning unit 414e does not clean the charging wire 414c, the image forming apparatus 1 controls the cleaning unit 414e to a release position where the cleaning unit 414e does not contact the charging wire 414c. When the cleaning unit 414e cleans the charging wire 414c, the image forming apparatus 1 controls the cleaning unit 414e at a contact position where the cleaning unit 414e contacts the charging wire 414c. When the cleaning unit 414e is in the release position, the image forming apparatus 1 increases or decreases the tension of the charging wire 414c. The image forming apparatus 1 maintains the tension of the charging wire 414c when the cleaning unit 414e is at the cleaning position.

  Therefore, the image forming apparatus 1 controls the tension of the charging wire 414c according to the position of the cleaning unit 414e, so that the pressing force from the charging wire 414c does not always act on the cleaning member 454. Therefore, since the aged deterioration of the cleaning member 454 can be suppressed, the life of the cleaning member 454 can be extended.

  In addition, when the charging wire 414c is cleaned by the cleaning member 454, the image forming apparatus 1 changes the shape in which the charging wire 414c is sandwiched into a V shape. Therefore, the image forming apparatus 1 can provide an inclination on the contact surface that contacts the charging wire 414c. Therefore, the amount of the charging wire 414c that bites into the cleaning member 454 varies depending on the position of the charging wire 414c. Accordingly, the image forming apparatus 1 can adjust the necessary number of cleanings according to the amount of biting, and thus can adjust the total number of cleanings of the cleaning member 454.

  In addition, the image forming apparatus 1 applies the tension of the charging wire 414c to the initial cleaning stage G1, which is the first stage from the installation of the photosensitive drum 413, the charging wire 414c, and the cleaning unit 414e to the preset time. By increasing the amount, the amount by which the charging wire 414c bites into the cleaning member 454 is increased. The image forming apparatus 1 causes the charging wire 414c to bite into the cleaning member 454 by reducing the tension of the charging wire 414c during the second cleaning stage G2 from the initial cleaning stage G1 to the lifetime of the cleaning member 454. Reduce the amount.

  Further, the image forming apparatus 1 sets the number of cleanings of the charging wire 414c to a first preset number in the initial cleaning G1, and sets the number of cleanings of the charging wire 414c to the first number in the last cleaning stage G2. Is set to a second number greater than. Therefore, the frequency | count of cleaning required for the cleaning initial stage G1 can be suppressed.

  Therefore, since the image forming apparatus 1 can reduce the total number of cleanings of the cleaning member 454 while maintaining the overall cleaning capability, the life of the cleaning member 454 can be extended.

  In the image forming apparatus 1, the tension adjusting unit 414 d is disposed outside the effective charging range 1000 of the photosensitive drum 413. Therefore, the tension adjusting unit 414d does not hinder charging of the photosensitive drum 413. Therefore, the image forming apparatus 1 can be configured to extend the life of the cleaning member 454 without hindering image formation by the photosensitive drum 413.

  In addition, the image forming apparatus 1 forms an image on a recording medium, for example, the paper P, when the charging wire 414c is cleaned by the cleaning unit 414e and the cleaning unit 414e is in the release position. Therefore, the image forming apparatus 1 can extend the life of the cleaning member 454 while maintaining the surface state of the charging wire 414c in a state suitable for charging. Therefore, the image forming apparatus 1 can reduce the replacement cost of the cleaning member 454 while maintaining the quality of the formed image.

  Further, when the cleaning unit 414e is replaced, the image forming apparatus 1 sets the number of image formations to a preset initial value. Therefore, the image forming apparatus 1 can control the number of cleanings of the charging wire 414c and the pressing force applied to the charging wire 414c in consideration of the life of the cleaning unit 414e. Therefore, the image forming apparatus 1 can appropriately control the number of cleanings of the charging wire 414c and the pressing force applied to the charging wire 414c, and can reduce the overall image forming cost.

  As described above, according to the image forming apparatus 1 according to the present embodiment, the image forming apparatus 1 forms an image by electrophotography, and the charging wire 414c for charging the photosensitive drum 413 and the charging wire 414c are applied. The cleaning unit 414e that cleans the charging wire 414c according to the pressing force applied, and when the cleaning unit 414e cleans the charging wire 414c, recording is performed after the photosensitive drum 413, the charging wire 414c, and the cleaning unit 414e are installed. A tension adjusting unit 414d that adjusts the pressing force applied to the charging wire 414c based on the tension of the charging wire 414c based on the number of times of forming an image on the medium, and a cleaning unit 414e is connected to the charging wire based on the number of image forming times. And a number-of-times control unit 802 that controls the number of times of cleaning for cleaning 414c. The cleaning member 454 is deformed by the pressing force given by the tension of the electric wire 414c. As the number of image formation increases, the pressing force from the charging wire 414c to the cleaning member 454 is reduced, and the number of cleaning of the charging wire 414c is reduced. It can be increased.

  Accordingly, the image forming apparatus 1 can maintain the cleaning capability of the cleaning member 454 for a long period of time, and can maintain the surface state of the charging wire 414c in a state suitable for charging. Can be used over a wide range.

  Further, according to the image forming apparatus 1 according to the present embodiment, the tension adjusting unit 414d reduces the tension of the charging wire 414c as the number of image formation increases, and the cleaning unit 414e reduces the tension of the charging wire 414c. As a result, the amount of biting of the charging wire 414c due to the deformation of the cleaning member 454 becomes smaller.

  As a result, the image forming apparatus 1 can suppress the deterioration amount of the cleaning member 454 over time to a constant amount, and thus can extend the life of the cleaning member 454.

  Further, according to the image forming apparatus 1 according to the present embodiment, the number control unit 802 increases the number of cleanings of the charging wire 414c as the number of image formations increases, and the number of cleanings of the charging wire 414c is the cleaning unit 414e. Makes one reciprocation of the charging wire 414c one time.

  As a result, the image forming apparatus 1 reduces the number of stains removed from the charging wire 414c by cleaning each time, but increases the number of times the cleaning unit 414e reciprocates the charging wire 414c correspondingly. As a whole, the cleaning ability of the cleaning member 454 can be maintained.

  Further, the image forming apparatus 1 according to the present embodiment further includes a position control unit 803 that controls the position of the cleaning unit 414e. The position control unit 803 is charged when the cleaning unit 414e does not clean the charging wire 414c. When the cleaning unit 414e is controlled to a release position where the wire 414c is not contacted, and the cleaning unit 414e cleans the charging wire 414c, the cleaning unit 414e is controlled to a cleaning position where the cleaning unit 414e contacts the charging wire 414c. Based on the controlled number of cleanings of the charging wire 414c, the cleaning unit 414e is reciprocated along the charging wire 414c, and the tension adjusting unit 414d starts cleaning the charging wire 414c when the cleaning unit 414e is in the release position. In this case, the tension of the charging wire 414c is increased or decreased, and the cleaning unit 414e is moved to the cleaning position. Ri, when continuing the cleaning of the charging wire 414c, is intended to maintain the tension of the charging wire 414c.

  As a result, the image forming apparatus 1 can suppress the deterioration of the cleaning member 454 over time, so that the life of the cleaning member 454 can be extended.

  Further, according to the image forming apparatus 1 according to the present embodiment, the cleaning member 454 has a contact surface that contacts the charging wire 414c, and the cleaning unit 414e has the first surface among the contact surfaces. The first support member 453a and the second support member 453b provided with the second surface among the contact surfaces, and the position control unit 803 is configured to charge the charging wire by the first surface and the second surface. When the charging wire 414c is cleaned while the 414c is sandwiched, the shape in which the charging wire 414c is sandwiched is changed to a V-shape.

  Accordingly, the image forming apparatus 1 can adjust the necessary number of cleanings according to the amount of biting, and thus can adjust the total number of cleanings of the cleaning member 454.

  Further, according to the image forming apparatus 1 according to the present embodiment, the tension adjusting unit 414d is in the first stage from the installation of the photosensitive drum 413, the charging wire 414c, and the cleaning unit 414e to a preset time. In the second stage from the first stage to the life of the cleaning member 454, the tension of the charging wire 414c is decreased, and the number control unit 802 increases the tension of the charging wire 414c in the first stage. The number of cleanings of the charging wire 414c is set to a preset first number, and in the second stage, the number of cleanings of the charging wire 414c is set to a second number greater than the first number. is there.

  As a result, the image forming apparatus 1 can reduce the total number of cleanings of the cleaning member 454 while maintaining the overall cleaning capability, and thus can extend the life of the cleaning member 454.

  Further, according to the image forming apparatus 1 according to the present embodiment, the tension adjusting unit 414d is disposed outside the effective charging range 1000 of the photosensitive drum 413, and adjusts the position of the charging wire 414c.

  Accordingly, the image forming apparatus 1 can be provided with a configuration that extends the life of the cleaning member 454 without hindering image formation by the photosensitive drum 413.

  In addition, the image forming apparatus 1 according to the present embodiment further includes the image forming unit 40 that forms an image on a recording medium, and the image forming unit 40 has the charging wire 414c cleaned by the cleaning unit 414e, and the cleaning unit 414e. When is in the release position, an image is formed on the recording medium.

  As a result, the image forming apparatus 1 can maintain the surface state of the charging wire 414c in a state suitable for charging, and can extend the life of the cleaning member 454. The replacement cost of the cleaning member 454 can be reduced.

  Further, according to the image forming apparatus 1 according to the present embodiment, the number control unit 802 sets the number of image formations to a preset initial value when the cleaning unit 414e is replaced.

  Accordingly, the image forming apparatus 1 can control the number of cleanings of the charging wire 414c and the pressing force applied to the charging wire 414c in consideration of the life of the cleaning unit 414e. The pressing force applied to the charging wire 414c can be appropriately controlled, and the overall image forming cost can be reduced.

  As described above, the image forming apparatus 1 according to the present invention has been described based on the embodiment. However, the present invention is not limited thereto, and modifications may be made without departing from the spirit of the present invention.

  For example, although an example in which the tension adjusting unit 414d is formed of a cam has been described, the present invention is not limited thereto, and the tension adjusting unit 414d may be formed of an elastic member. That is, it is sufficient if the position of the charging wire 414c can be pushed down to the cleaning member 454 side.

  Further, although an example of the charging device 414 having one charging wire 414c has been described, the invention is not limited thereto, and the charging device 414 having two or more charging wires 414c may be used. When a plurality of charging wires 414c are provided, each charging wire 414c may be provided along the outer shape of the photosensitive drum 413, for example.

  In addition, in the present embodiment, the image forming apparatus 1 is configured to perform full color printing, but is not limited thereto, and may be configured to perform monochrome printing.

  Further, although an example in which the photosensitive drum 413 having a drum shape is provided as the photosensitive member has been described, the invention is not limited thereto, and a photosensitive belt having a belt shape may be provided as the photosensitive member. That is, any material that functions as a photoconductor is acceptable.

DESCRIPTION OF SYMBOLS 1 Image forming apparatus 20 Operation display part 40 Image forming part 41, 41Y, 41M, 41C, 41K Image forming unit 42 Intermediate transfer unit 411 Exposure device 412 Developing device 413 Photosensitive drum 414 Charging device 414a Charging block 414c Charging wire 414d Tension adjustment unit 414e Cleaning unit 415 Drum cleaning device 421 Intermediate transfer belt 422 Primary transfer roller 423 Support roller 424 Secondary transfer roller 426 Belt cleaning device 451 Base portion 453a First support member 453b Second support member 454, 454a, 454b Cleaning member 50 Transport path 51 Switching gate 52 Refeed transport path 53 Loop roller 54 Registration roller 55 Reverse roller 58 Paper discharge roller 59 Paper discharge tray 60 Fixing section 601 Fixing roller 601 602 Pressure roller 603 Heating unit 70 Paper transport unit 71 Paper feed tray 72 Paper feed unit 80 Control unit 801 Tension control unit 802 Number control unit 803 Position control unit 805 Timing unit 810 Image processing unit 1000 Charging effective range P Paper C Initial Position D1 First state D2 Second state D3 Third state D4 Fourth state E, F NG line G1 Initial cleaning stage G2 Final cleaning stage J, K diagram SC Document reading device

Claims (9)

An image forming apparatus for forming an image by electrophotography,
A charging wire for charging the photosensitive drum;
According to the pressing force applied to the charging wire, a cleaning unit for cleaning the charging wire;
When the cleaning unit cleans the charging wire, the charging wire is applied to the charging wire based on the number of image formations on the recording medium after the photosensitive drum, the charging wire, and the cleaning unit are installed. A tension adjusting unit that adjusts the pressing force applied by the tension of the charging wire;
A cleaning control unit that controls the number of cleanings for cleaning the charging wire based on the number of times of image formation;
The cleaning unit
It has a cleaning member that is deformed by the pressing force given by the tension of the charging wire,
As the number of times of image formation increases, the pressing force from the charging wire to the cleaning member is reduced, and the number of times of cleaning of the charging wire is increased. The tension adjusting unit is
As the number of image formation increases, the tension of the charging wire is reduced,
The cleaning unit
The image forming apparatus according to claim 1, wherein as the tension of the charging wire is reduced, an amount of biting of the charging wire due to deformation of the cleaning member is reduced. The frequency controller is
As the number of times of image formation increases, the number of cleaning of the charging wire is increased,
The number of cleanings of the charging wire is
The image forming apparatus according to claim 2, wherein the cleaning unit reciprocates the charging wire once. A position control unit for controlling the position of the cleaning unit;
The position controller is
When the cleaning unit does not clean the charging wire, the cleaning unit is controlled to a release position that does not contact the charging wire,
When the cleaning unit cleans the charging wire, the cleaning unit is controlled at a cleaning position for contacting the charging wire,
Based on the number of cleanings of the charging wire controlled by the number control unit, the cleaning unit is reciprocated along the charging wire,
The tension adjusting unit is
When the cleaning unit is in the release position and starts cleaning the charging wire, the tension of the charging wire is increased or decreased,
The image forming apparatus according to claim 3, wherein when the cleaning unit is at the cleaning position and the cleaning of the charging wire is continued, the tension of the charging wire is maintained. The cleaning member is
A contact surface is formed in contact with the charging wire;
The cleaning unit
Of the contact surfaces, a first support member provided with a first surface;
A second support member provided with a second surface among the contact surfaces;
The position controller is
The image forming apparatus according to claim 4, wherein when the charging wire is sandwiched between the first surface and the second surface to clean the charging wire, a shape in which the charging wire is sandwiched is V-shaped. The tension adjusting unit is
In the first stage from the installation of the photosensitive drum, the charging wire and the cleaning unit to a preset time, the tension of the charging wire is increased,
In the second stage from the first stage to the life of the cleaning member, the tension of the charging wire is reduced,
The frequency controller is
In the first step, the number of cleanings of the charging wire is set to a preset first number,
6. The image forming apparatus according to claim 5, wherein, in the second stage, the charging wire cleaning frequency is set to a second frequency greater than the first frequency. The tension adjusting unit is
The image forming apparatus according to claim 6, wherein the image forming apparatus is disposed outside an effective charging range of the photosensitive drum and adjusts a position of the charging wire. An image forming unit for forming an image on the recording medium;
The image forming unit includes:
The image forming apparatus according to claim 7, wherein when the charging wire is cleaned by the cleaning unit and the cleaning unit is in the release position, an image is formed on the recording medium. The frequency controller is
The image forming apparatus according to claim 1, wherein when the cleaning unit is replaced, the number of times of image formation is set to a preset initial value.

Images