JP6638433B2 - Charging device and image forming apparatus provided with the charging device - Google Patents

Description

  The present invention relates to a charging device and an image forming apparatus provided with the charging device.

  2. Description of the Related Art An electrophotographic image forming apparatus (printer, copier, facsimile, etc.) is provided with a charging device for charging the surface of a photoconductor. The charging device charges the outer peripheral surface of the photoconductor by applying a predetermined high voltage to the charging wire and performing corona discharge.

  The corona discharge by the charging wire generates discharge products such as ozone and nitrogen oxides. Further, around the charging device, toner is scattered, and paper dust and dust float. For this reason, stains such as discharge products and scattered toner are likely to adhere to the charging wire.

  When dirt adheres to the charging wire, the discharge efficiency of the charging wire is reduced, the discharge becomes uneven, and the charging on the surface of the photoconductor becomes uneven. As a result, unevenness or the like occurs in the image formed on the paper.

  Therefore, a technique has been developed in which the charging wire is periodically cleaned to remove dirt attached to the charging wire. For example, Patent Literature 1 discloses a technique for cleaning a charging wire by moving a cleaning pad, which is in contact with the charging wire with a predetermined pressing force, in the axial direction of the charging wire. Patent Document 1 discloses that the pressing force of the cleaning pad against the charging wire is increased each time the cleaning operation is completed, and that the pressing force of the cleaning pad against the charging wire is increased each time the number of printed sheets increases. Have been.

JP 2011-70095 A

  However, since the pressing force of the cleaning pad against the charging wire is constant within one cleaning operation, if there is unevenness in the dirt attached to the charging wire, the pressing force may be excessive or insufficient. In other words, with respect to a portion with little dirt, the charging wire is cleaned with an excessive pressing force, thereby shortening the life of the charging wire and the cleaning pad. In addition, for a portion having a large amount of dirt, the charging wire cannot be cleaned with a sufficient pressing force, and the dirt cannot be sufficiently removed.

  The present invention has been made in view of the above circumstances. That is, an object of the present invention is to provide a charging device or the like that can remove actual dirt adhering to a charging wire without excess or shortage.

(1) a charging wire for charging the discharge member to be charged, by moving the cleaning pad is brought into contact with the charging wire in the axial direction of the charging wire, a cleaning member for cleaning the charging wire, the charging A guide plate installed along the axial direction of the wire , wherein the cleaning member is provided for the charging wire in accordance with an increase or decrease in a frictional force between the charging wire and the cleaning pad that occurs when cleaning is performed. have a mechanism to increase or decrease the pressing force of the cleaning pad comprises a guide plate disposed along the axial direction of the charging wire, the cleaning member includes a holding member for holding the cleaning pad, said retaining member A supporting base material that supports and is rotatable in a plane parallel to the surface of the guide plate, wherein the supporting base material is When moving in the axial direction of the charging wire along the id plate, depending on the friction force increases or decreases occurring between the charging wire and the cleaning pad, causing the pace at which the inclination with respect to the guide plate of the cleaning member Thereby, the cleaning member moves parallel to the guide plate without being inclined, or the cleaning member moves inclined with respect to the guide plate, and the support base member generated by the inclination The increase / decrease in the frictional force between the guide plate and the guide plate is converted into a rotational force in the plane of the support base material, and the pressing force of the cleaning pad against the charging wire is increased / decreased in accordance with the increase / decrease in the rotational force. To make the charging device.

( 2 ) The holding member includes a pair of holding members, each of which holds the cleaning pad and is disposed so as to sandwich the charging wire, and one of the pair of holding members. The first holding member is disposed on the front end side in the traveling direction of the support substrate, and the other second holding member is disposed on the rear end side in the traveling direction of the support substrate, and the rotational force of the support substrate is The charging device according to ( 1 ), wherein the pair of holding members rotate in a direction to push the charging wire in accordance with ( 1 ), thereby increasing a pressing force of the cleaning pad against the charging wire.

( 3 ) On the guide plate side of the support base, a pair of sliding protrusions that are in contact with the guide plate are arranged, and the pair of sliding protrusions are arranged so as to sandwich the charging wire; Of the pair of sliding protrusions, one of the first sliding protrusions is disposed at a front end side in the traveling direction of the support base material and at a position facing the first holding member with the charging wire interposed therebetween, The other second sliding protrusion is disposed at a rear end side in the traveling direction of the support base material and at a position facing the second holding member with the charging wire interposed therebetween, and the first sliding protrusion or the The charging device according to ( 2 ), wherein the support base rotates in the plane due to an increase or decrease in a frictional force between a second sliding protrusion and the guide plate.

( 4 ) The charging device according to any one of ( 1 ) to ( 3 ), further including a moving member configured to move the cleaning member, wherein the moving member holds a rotation axis of the support base.

( 8 ) An image forming apparatus comprising the charging device according to any one of the above (1) to ( 7 ).

  According to the present invention, the pressing force of the cleaning pad on the charging wire is increased or decreased in accordance with the actual degree of contamination of the charging wire (specifically, the increase or decrease of the frictional force between the charging wire and the cleaning pad). . Thereby, the actual stain adhering to the charging wire can be removed without excess or deficiency.

FIG. 2 is a schematic configuration diagram of an image forming apparatus. It is a schematic perspective view of a charging device. (A) It is a side view of a cleaning member. (B) It is a top view of a cleaning member. (A) is a figure (side view) for explaining operation of a cleaning member at the time of dirt increase. (B) is a figure (top view) for explaining operation of a cleaning member at the time of dirt increase. (A) is a figure (side view) for explaining operation of a cleaning member at the time of dirt reduction. (B) is a figure (top view) for explaining operation of a cleaning member at the time of dirt reduction.

  Hereinafter, embodiments of the present invention will be described with reference to the accompanying drawings. In the description of the drawings, the same elements will be denoted by the same reference symbols, without redundant description. Further, the dimensional ratios in the drawings are exaggerated for the sake of explanation, and may differ from the actual ratios.

[Image forming apparatus 100]
FIG. 1 is a schematic configuration diagram of the image forming apparatus 100.

(1) Overall Configuration The image forming apparatus 100 according to the present embodiment is a printer, a copier, a facsimile, a multifunction peripheral, or the like having at least a function of forming an image on a sheet S.

  As a specific hardware configuration, as shown in FIG. 1, the image forming apparatus 100 includes a control unit 110, an operation panel unit 120, a communication unit 130, a sheet storage unit 140, an image forming unit 150, The image forming apparatus includes a fixing unit 160 and a paper discharging unit 170.

(1-1) Control Unit 110
The control unit 110 controls the entire image forming apparatus 100. For example, the control unit 110 has a CPU (Central Processing Unit), a memory, and a storage.

  The CPU is a control circuit composed of a multi-core processor or the like that executes control of the above-described units and various types of arithmetic processing according to programs. Each function of the image forming apparatus 100 is such that the CPU executes a corresponding program. Demonstrated by

  The memory is a high-speed accessible main storage device that temporarily stores programs and data as a work area. As the memory, for example, DRAM (Dynamic Random Access Memory), SDRAM (Synchronous Dynamic Random Access Memory), SRAM (Static Random Access Memory) and the like are adopted.

  The storage is a large-capacity auxiliary storage device that stores various programs including the operating system and various data. For the storage, for example, a hard disk, a solid state drive, a flash memory, a ROM, and the like are employed.

(1-2) Operation Panel Unit 120
The operation panel unit 120 includes a display unit such as a display, and a transparent operation panel attached to the display surface of the display unit. The operation panel unit 120 specifies a touch position corresponding to the XY coordinates of the image displayed on the display unit, converts the touch position into coordinates, and outputs the coordinates. The operation panel unit 120 is configured by a pressure-sensitive or electrostatic input detection element or the like.

(1-3) Communication unit 130
The communication unit 130 is an interface for communicating with an external device (for example, a host computer) via a network.

(1-4) Paper Storage Unit 140
The paper storage unit 140 is a paper feed tray that stores the paper S. The paper S is transported from the paper storage unit 140 to a position of a transfer roller of the image forming unit 150 described later by driving a paper feed roller or the like.

(1-5) Image Forming Unit 150
The image forming unit 150 forms a toner image by an image forming process such as an electrophotographic method and transfers the toner image to the sheet S. For example, the image forming unit 150 is a tandem type having an independent photosensitive drum 151 (Y, M, C, K) for each of Y (yellow), M (magenta), C (cyan), and K (black). Is adopted. A charging device 152, an exposing device, a developing device, and a cleaning device are provided for each color along the outer periphery of the photoconductor drum 151 (Y, M, C, K), and the photoconductor drum 151 (Y, M, C) is provided. , K), toner images of each color are formed. The toner images of each color formed on the photoconductor drum 151 (Y, M, C, K) are sequentially transferred onto the intermediate transfer belt, and the toner images (Y, M, C, K) on which the layers of the respective colors (Y, M, C, K) are superimposed. (Color image) is formed on the intermediate transfer belt. Here, the intermediate transfer belt is an endless belt, is wound around a plurality of rollers, and is supported so as to run. Then, by applying a bias having a polarity opposite to that of the toner to the transfer roller, the toner image formed on the intermediate transfer belt is transferred onto the sheet S.

  However, the image forming unit 150 may employ a rotary method (direct transfer method) instead of the tandem method (intermediate transfer method) as described above.

(1-6) Fixing unit 160
The fixing unit 160 includes a pair of fixing rollers, and fixes the toner image transferred onto the sheet S onto the sheet S by heating the toner image. For example, the fixing unit 160 presses one fixing roller used as a heating source to the other fixing roller used as a pressing member. As a result, heat and pressure are applied to the sheet S at the fixing nip, and the toner image is fused and fixed.

(1-7) Paper discharge unit 170
The paper discharge unit 170 is a paper discharge tray on which the paper S on which an image is formed is stacked. After passing through the fixing unit 160, the sheet S is discharged onto a discharge tray by driving a discharge roller or the like.

(2) Charging device 152
Next, the charging device 152 of the present embodiment will be described in detail. The charging devices 152 (Y, M, C, and K) provided for each color have the same configuration and function, and therefore, hereinafter, “Y” and “M” are used as necessary. , "C", and "K" are used, and the description will be made generally.

  FIG. 2 is a schematic perspective view of the charging device 152.

  As shown in FIG. 2, the charging device 152 includes a charging wire 501 to which a predetermined voltage is applied to perform a corona discharge on a photosensitive surface on an outer periphery of the photosensitive drum (charged body) 151. Further, the charging device 152 includes a shield case (not shown) as a housing that stretches and supports the charging wire 501 inside. With this shield case, the charging wire 501 is stretched and supported over the entire length of the photosensitive drum 151 in the longitudinal direction (X direction shown in FIG. 2) so as to be parallel to the rotation center line of the photosensitive drum 151. In addition, the charging device 152 has a grid (not shown) between the charging wire 501 and the photosensitive drum 151 for uniformly performing corona discharge of the charging wire 501 on the photosensitive surface.

  In addition, the charging device 152 includes a cleaning member 502 that periodically cleans the charging wire 501 because discharge products generated by corona discharge and dirt such as scattered toner adhere to the charging wire 501. Further, the charging device 152 includes two plate-shaped guide plates 503 arranged in parallel (with a certain interval in the Y direction shown in FIG. 2) along the axial direction of the charging wire 501. . Note that the guide plate 503 may be formed of a conductive member (metal plate) and function as a back plate of the shield case. The cleaning member 502 can reciprocate in the axial direction (X direction shown in FIG. 2) of the charging wire 501 using the guide plate 503 as a guide.

  FIG. 3A is a side view of the cleaning member 502, and FIG. 3B is a top view of the cleaning member 502.

  As shown in FIG. 3A, the cleaning member 502 includes a pair of first and second cleaning pads 521a and 521b, a pair of first and second holding members 522a and 522b, and a support base material 523. ing.

  The first and second cleaning pads 521a and 521b are members that remove dirt attached to the charging wire 501 by friction.

  As shown in FIGS. 3A and 3B, the first and second holding members 522a and 522b extend in a direction (for example, a substantially vertical direction) from the surface of the support base material 523 toward the charging wire 501. , Each of which is a columnar member that holds the first and second cleaning pads 521a and 521b (for example, at the tip). The first and second holding members 522a and 522b are disposed between the two guide plates 503, and have a length necessary for the wound first and second cleaning pads 521a and 521b to contact the charging wire 501. Having.

  The support base member 523 supports the first and second holding members 522a and 522b, and is configured to be rotatable in a plane (XY plane) parallel to the surface of the guide plate 503. For example, a rotating shaft 524 is provided at the center of the support base material 523, and the rotating shaft 524 is inserted into a through hole of the moving member 550, and the entire cleaning member 502 is held by the moving member 550. The movement of the moving member 550 in the axial direction of the charging wire 501 is controlled according to an instruction from the control unit 110.

  As shown in FIGS. 3A and 3B, a pair of first and second sliding protrusions 525a and 525b that are in contact with the guide plate 503 are arranged on the guide plate 503 side of the support base material 523. ing. The first and second sliding protrusions 525a, 525b are arranged at diagonal positions on the support base 523 with the charging wire 501 interposed therebetween.

(3) Operation of Cleaning Member 502 Next, the operation of the cleaning member 502 will be described.

(3-1) Operation when Dirt Does Not Adhere to Charging Wire 501 First, the operation of the cleaning member 502 when dirt does not adhere to the charging wire 501 will be described.

  FIGS. 3A and 3B show the relationship of forces acting on each part when the cleaning member 502 cleans the charging wire 501 while moving in the direction of the black arrow (+ X direction).

  When the cleaning member 502 cleans the charging wire 501, a force in the traveling direction is applied to the cleaning member 502 via the moving member 550.

  At this time, the first cleaning pad 521a disposed on the distal end side of the rotation axis 524 of the support base member 523 in the advancing direction is in contact with the charging wire 501, so that the first cleaning pad 521a is located Causes friction. Therefore, as shown in FIG. 3A, the first cleaning pad 521a receives a frictional force R1 from the charging wire 501 in a direction (−X direction) opposite to the traveling direction of the cleaning member 502.

  Similarly, since the second cleaning pad 521 b disposed on the rear end side of the rotation axis 524 of the support base member 523 in the advancing direction is in contact with the charging wire 501, the second cleaning pad 521 b is in contact with the charging wire 501. Friction occurs between them. Therefore, as shown in FIG. 3A, the second cleaning pad 521b also receives the frictional force R2 from the charging wire 501 in the direction (−X direction) opposite to the traveling direction of the cleaning member 502.

  However, when no dirt is attached to the charging wire 501, the frictional forces R1 and R2 are extremely small. Therefore, as shown in FIG. 3A, the cleaning member 502 (particularly, the support base material 523) moves parallel to the guide plate 503 without being inclined.

  When the cleaning member 502 is kept parallel to the guide plate 503, the force exerted on the guide plate 503 from the support base material 523 via the first sliding protrusion 525a and the force exerted on the guide plate 503 via the second sliding protrusion 525b. The force exerted on the guide plate 503 from the support base material 523 is substantially equal. Therefore, the normal forces N1 and N2 of the respective forces are also substantially equal (N1 ≒ N2).

  Since the first sliding protrusion 525a and the second sliding protrusion 525b are formed of the same material, the dynamic friction coefficient μ between the first and second sliding protrusions 525a, 525b and the guide plate 503 is also large. equal.

  Therefore, the frictional force “μ · N1” received by the first sliding protrusion 525a from the guide plate 503 is substantially equal to the frictional force “μ · N2” received by the second sliding protrusion 525b from the guide plate 503 (μ · N2). N1 ≒ μ · N2).

  At this time, the frictional force “μ · N1” from the first sliding protrusion 525a causes the support base material 523 to rotate in the clockwise direction, and the frictional force “μ · N1” from the second sliding protrusion 525b. The force for rotating the support base material 523 in the counterclockwise direction by “N2” is balanced. Therefore, as shown in FIG. 3B, the support base material 523 moves in the traveling direction without rotating. During this time, the first and second cleaning pads 521a and 521b are in contact with the charging wire 501 with the minimum pressing force P.

  Thus, when the charging wire 501 is not contaminated, the charging wire 501 is not cleaned with an excessive pressing force, and the life of the charging wire 501 and the first and second cleaning pads 521a and 521b is shortened. Hateful.

(3-2) Operation When Dirt Adhering to Charging Wire 501 During Movement Next, operation of cleaning member 502 when dirt adhering to charging wire 501 during movement increases will be described. I do.

  FIG. 4A is a diagram (side view) for explaining the operation of the cleaning member 502 when the contamination increases. FIG. 4B is a diagram (top view) for explaining the operation of the cleaning member 502 when dirt increases.

  Friction between the charging wire 501 and the first cleaning pad 521a is large in a portion where a large amount of dirt is attached (a broken line portion shown in FIG. 4A). Therefore, as shown in FIG. 4A, the frictional force R1 'received by the first cleaning pad 521a from the charging wire 501 increases (R1'> R1).

  Similarly, the friction between the charging wire 501 and the second cleaning pad 521b increases in a portion where a large amount of dirt is attached. Therefore, as shown in FIG. 4A, the frictional force R2 'received by the second cleaning pad 521b from the charging wire 501 also increases (R2'> R2).

  At this time, if the cleaning member 502 is viewed integrally, the cleaning member 502 receives frictional forces R1 ′ and R2 ′ in a direction (−X direction) opposite to the traveling direction at a position away from the center of gravity position G. become. Therefore, as shown in FIG. 4A, the cleaning member 502 inclines in a direction in which the tip side in the traveling direction of the support base material 523 approaches the guide plate 503. The inclination at this time becomes steep as the frictional forces R1 'and R2' increase.

  When the cleaning member 502 is inclined as shown in FIG. 4A, the force exerted on the guide plate 503 from the support base material 523 via the first sliding protrusion 525a increases. On the contrary, the force exerted on the guide plate 503 from the support base material 523 via the second sliding protrusion 525b is reduced. Therefore, the normal force N1 'increases (N1'> N1), and the normal force N2 'decreases (N2'≤N2). When the second sliding protrusion 525b and the guide plate 503 are completely separated from each other, the normal force N2 '= 0.

  Therefore, the frictional force “μ · N1 ′” received by the first sliding protrusion 525a from the guide plate 503 is larger than the frictional force “μ · N2 ′” received by the second sliding protrusion 525b from the guide plate 503 (μ). N1 '> μN2').

  At this time, the frictional force “μ · N1 ′” from the first sliding protrusion 525a causes the support base material 523 to rotate in the clockwise direction due to the frictional force “μ” from the second sliding protrusion 525b. N2 ′ ”is larger than the force for rotating the support base material 523 in the counterclockwise direction. Therefore, as shown in FIG. 4B, the support base material 523 rotates clockwise. That is, the support base material 523 rotates in a direction to increase the rotation angle θ shown in FIG. As a result, the pressing force P 'of the first and second cleaning pads 521a, 521 against the charging wire 501 increases (P'> P).

  As described above, when the contamination of the charging wire 501 increases with the movement of the cleaning member 502, the pressing force P ′ of the first and second cleaning pads 521a, 521 on the charging wire 501 increases according to the degree of the contamination. Can be done. Therefore, dirt attached to the charging wire 501 can be removed without excess or deficiency.

(3-3) Operation when the amount of dirt attached to the charging wire 501 during the movement decreases Next, during the movement, the part passes through the portion of the charging wire 501 that is much dirty and relatively adheres to the charging wire 501. The operation of the cleaning member 502 when dirt is reduced will be described.

  FIG. 5A is a diagram (side view) for explaining the operation of the cleaning member 502 when dirt is reduced. FIG. 5B is a diagram (top view) for explaining the operation of the cleaning member 502 when dirt is reduced.

  When the amount of dirt attached to the charging wire 501 decreases, the friction between the charging wire 501 and the first cleaning pad 521a decreases. Therefore, as shown in FIG. 5A, the frictional force R1 ″ applied to the first cleaning pad 521a from the charging wire 501 decreases (R1 ″ <R1 ′).

  Similarly, the friction between the charging wire 501 and the second cleaning pad 521b decreases as the dirt decreases. Therefore, as shown in FIG. 5A, the frictional force R2 ″ received by the second cleaning pad 521b from the charging wire 501 also decreases (R2 ″ <R2 ′).

  At this time, if the cleaning member 502 is viewed integrally, the frictional forces R1 "and R2" of the cleaning member 502 received at a position away from the center of gravity G are reduced. Therefore, as shown in FIG. 5A, the cleaning member 502 is inclined such that the front end side of the supporting base material 523 in the traveling direction is separated from the guide plate 503. The inclination at this time becomes gentle as the frictional forces R1 "and R2" decrease.

  When the inclination of the cleaning member 502 becomes gentle as shown in FIG. 5A, the force exerted on the guide plate 503 from the support base material 523 via the first sliding protrusion 525a decreases. Conversely, the force exerted on the guide plate 503 from the support base material 523 via the second sliding protrusion 525b increases. Therefore, the normal force N1 "decreases (N1" <N1 '), and the normal force N2 "increases (N2"? N2'). When the second sliding protrusion 525b and the guide plate 503 are completely separated from each other, the normal force N2 ″ = 0.

  Therefore, the frictional force “μ · N1 ″” received by the first sliding protrusion 525a from the guide plate 503 is reduced (μ · N1 ″ <μ · N1 ′), and the support base material 523 will be rotated clockwise. And the force to be reduced.

  At the same time, due to the tension of the charging wire 501, the first and second cleaning pads 521a and 521b receive the repulsive force from the charging wire 501, and the force for rotating the supporting base material 523 in the counterclockwise direction is relatively high. Become larger. Therefore, as shown in FIG. 5B, the support base material 523 rotates in a counterclockwise direction. That is, the support base material 523 rotates in a direction in which the rotation angle θ ′ shown in FIG. As a result, the pressing force P ″ of the first and second cleaning pads 521a, 521 against the charging wire 501 decreases (P ″ <P ′).

  As described above, when the contamination of the charging wire 501 decreases with the movement of the cleaning member 502, the pressing force P ″ of the first and second cleaning pads 521a and 521b on the charging wire 501 decreases according to the degree of the contamination. Therefore, the dirt attached to the charging wire 501 can be removed without excess or deficiency.

(4) Conclusion As described above, the cleaning member 502 of the present embodiment uses the cleaning pad 521 for the charging wire 501 in accordance with the increase and decrease of the frictional forces R1 and R2 between the charging wire 501 and the cleaning pad 521 generated during cleaning. Has a mechanism for increasing or decreasing the pressing force P of the pressure. As a result, the actual stain adhering to the charging wire 501 can be removed without excess or deficiency. Further, even if the dirt adhering to the charging wire 501 is uneven, all the dirt can be completely and simply removed by moving the cleaning member 502 once in the X direction. Furthermore, the charging wire 501 is not cleaned with an excessive pressing force P, and the life of the charging wire 501 and the first and second cleaning pads 521a and 521b is not easily shortened. Further, since it is not necessary to increase the number of times of cleaning every time the number of printed sheets increases, there is no problem that the downtime due to the cleaning of the charging wire 501 is increased and the productivity is reduced.

  Further, more specifically, the cleaning member 502 of the present embodiment is configured such that the front end side of the support base material 523 in the advancing direction of the support base material 523 is increased or decreased according to the increase or decrease of the frictional forces R1 and R2 generated between the charging wire 501 and the cleaning pad 521. It inclines in the direction approaching or separating from the guide plate 503. Then, the increase and decrease of the frictional forces R1 and R2 between the support base 523 and the guide plate 503 caused by the inclination are converted into the rotational force of the support base 523. Further, the pressing force P of the cleaning pad 521 against the charging wire 501 is increased or decreased according to the increase or decrease of the rotational force. Since the dirt attached to the charging wire 501 is removed by such a mechanical mechanism, it is not necessary to introduce software or the like for controlling the pressing force P of the cleaning pad 521. Even when the cleaning member 502 of the present embodiment is put into the charging device 152 that has been used halfway, the current state of the charging wire 501 is immediately adjusted without setting software. Cleaning can be performed with the pressing force P. Further, according to such a mechanism, not only when the cleaning member 502 is moved in the + X direction but also when it is moved in the -X direction, the dirt on the charging wire 501 can be removed by the same principle, and cleaning can be performed efficiently.

  In addition, the support base member 523 of the present embodiment supports the pair of holding members 522, and among the pair of holding members 522, the first holding member 522a is disposed on the tip side in the traveling direction of the support base member 523. The second holding member 522b is disposed on the rear end side of the support base material 523 in the traveling direction. The pressing force P of the cleaning pad 521 against the charging wire 501 is increased by rotating the pair of holding members 522 in the direction of pressing the charging wire 501 according to the rotational force of the support base material 523. With such a simple mechanism, the rotational force of the support base material 523 can be easily converted into the pressing force P of the cleaning pad 521 against the charging wire 501. In addition, since the mechanism is simple, no time is required for manufacturing, and the manufacturing cost can be reduced.

  Further, a pair of sliding protrusions 525 that are in contact with the guide plate 503 are arranged on the guide plate 503 side of the support base material 523 of the present embodiment. Of the pair of sliding protrusions 525, the first sliding protrusion 525a is located on the leading end side in the traveling direction of the support base material 523, and the first holding member 522a with the charging wire 501 interposed therebetween when the cleaning member 502 is viewed from above. It is arranged at the position facing to. Further, the second sliding protrusion 525b is disposed at a rear end side in the traveling direction of the support base material 523 and at a position facing the second holding member 522b with the charging wire 501 interposed therebetween when the cleaning member 502 is viewed from above. Have been. Then, as the frictional force between the first sliding protrusion 525a or the second sliding protrusion 525b and the guide plate 503 increases or decreases, the support base member 523 rotates. With such a simple mechanism, the inclination of the support base 523 caused by the frictional forces R1 and R2 between the charging wire 501 and the cleaning pad 521 can be easily converted into the rotational force of the support base 523. In addition, since the mechanism is simple, no time is required for manufacturing, and the manufacturing cost can be reduced.

<Modification>
The above embodiments are intended to illustrate the gist of the present invention and do not limit the present invention. Many alternatives, modifications, and variations will be apparent to those skilled in the art.

  For example, in the above embodiment, the first and second sliding protrusions 525a and 525b are formed in a hemispherical shape. Accordingly, the first and second sliding protrusions 525a and 525b and the guide plate 503 are less likely to be worn by friction. However, the present invention is not limited to this, and the shapes of the first and second sliding protrusions 525a, 525b may be changed. Further, the first and second sliding protrusions 525a and 525b do not need to be accurately arranged at the positions shown in FIG. 3B, and may be close to the charging wire 501 or close to the rotating shaft 524. Good.

  In addition, the shape of the first and second holding members 522a and 522b is not limited to this, and may be changed to a columnar member. Further, the positions of the first and second holding members 522a and 522b do not need to be accurately arranged at the positions shown in FIG.

  Further, the configuration of the image forming apparatus 100 described above is a main configuration in describing the features of the above embodiments, and is not limited to the above configuration. Further, the configuration provided in the general image forming apparatus 100 is not excluded.

  Further, the invention of the present application is not limited by the way of classification and the names of the above-described configurations.

100 image forming apparatus,
110 control unit,
120 operation panel section,
130 communication unit,
140 paper compartment,
150 image forming unit,
151 photosensitive drum (charged body),
152 charging device,
160 fixing unit,
170 paper output unit,
501 charging wire,
502 cleaning member,
503 guide plate,
521a, b first and second cleaning pads,
522a, b first and second holding members,
523 support base material,
524 rotation axis,
525a, b first and second sliding protrusions,
550 Moving member.

Claims (5)

A charging wire for charging an object to be charged by discharging,
A cleaning member that cleans the charging wire by moving a cleaning pad in contact with the charging wire in the axial direction of the charging wire,
A guide plate installed along the axial direction of the charging wire ,
The cleaning member,
Depending on the frictional force increases or decreases between said charging wire generated when cleaning with the cleaning pad, have a mechanism to increase or decrease the pressing force of the cleaning pad relative to the charging wire,
A holding member that holds the cleaning pad, and a support base that supports the holding member and is rotatable in a plane parallel to the surface of the guide plate,
When the supporting substrate moves in the axial direction of the charging wire along the guide plate during cleaning, the cleaning member is moved in accordance with an increase or decrease in a frictional force generated between the charging wire and the cleaning pad . By causing the inclination with respect to the guide plate to be gentle, the cleaning member moves in parallel to the guide plate without being inclined, or the cleaning member moves while being inclined with respect to the guide plate. ,
Increase / decrease of the frictional force between the support base and the guide plate caused by the inclination is converted into a rotational force in the plane of the support base,
A charging device that increases or decreases the pressing force of the cleaning pad on the charging wire in accordance with the increase or decrease in the rotational force. The holding member includes a pair of holding members,
The pair of holding members, each holding the cleaning pad, is disposed so as to sandwich the charging wire,
Of the pair of holding members, one of the first holding members is disposed on the front end side in the traveling direction of the support base material, and the other second holding member is disposed on the rear end side in the traveling direction of the support base material. ,
2. The charging device according to claim 1 , wherein the pressing force of the cleaning pad against the charging wire is increased by rotating the pair of holding members in a direction of pressing the charging wire in accordance with the rotational force of the support base. 3. On the guide plate side of the support substrate, a pair of sliding protrusions that are in contact with the guide plate are arranged,
The pair of sliding protrusions are arranged so as to sandwich the charging wire,
Of the pair of sliding protrusions, one of the first sliding protrusions is disposed at a front end side in the traveling direction of the support base material and at a position facing the first holding member with the charging wire interposed therebetween, The other second sliding protrusion is arranged at a rear end side in the traveling direction of the support base material and at a position facing the second holding member with the charging wire interposed therebetween,
The charging device according to claim 2 , wherein the support base rotates in the plane by increasing or decreasing a frictional force between the first sliding protrusion or the second sliding protrusion and the guide plate. A moving member for moving the cleaning member,
The charging device according to any one of claims 1 to 3 , wherein the moving member holds a rotation axis of the support base. An image forming apparatus having a charging device according to any one of claims 1-4.