Charging device, image forming unit, and image forming apparatus

Abstract

The invention provides a charging device, an image forming unit, and an image forming apparatus. The charging device includes: a discharge electrode; a control electrode that is disposed between the discharge electrode and a charged body charged by the discharge electrode, and that bends or bends along the surface shape of the charged body; a cleaning member that cleans at least the control electrode among the discharge electrode and the control electrode; and a deformation member that deforms the shape of the control electrode to different shapes during cleaning by the cleaning member and during electrification.

Description

Technical Field

[0001] The present invention relates to a charging device, an image forming unit, and an image forming device. Background Art

[0002] Conventionally, as technologies related to charging devices, technologies disclosed in Patent Documents 1 and 2, for example, have been proposed.

[0003] In Patent Document 1, the structure is as follows: in order to avoid the distance between the charged body and the control electrode varying depending on the position, the control electrode is arranged in a shape along the curvature of the charged body, and the surface of the control electrode on the side opposite to the charged body is cleaned by a cleaning component (paragraphs

[0022] and

[0028] of Patent Document 1).

[0004] Patent Document 2 has a structure in which both surfaces of a control electrode formed into a planar shape can be cleaned by a cleaning member (paragraphs

[0056] , [ Figure 4 ]).

[0005] Patent Document 1: Japanese Patent Application Laid-Open No. 2009-086091

[0006] Patent Document 2: Japanese Patent Application Publication No. 2019-045801 Summary of the Invention

[0007] An object of the present invention is to prevent a control electrode from contacting a surface of a charged object and to improve the cleaning performance of a control electrode, compared to a case where the control electrode is cleaned while being kept in the same shape as when charged.

[0008] The invention according to claim 1 is a charging device comprising:

[0009] discharge electrode;

[0010] a control electrode disposed between the discharge electrode and a charged object charged by the discharge electrode, and bent or folded along a surface shape of the charged object;

[0011] a cleaning member for cleaning at least the control electrode among the discharge electrode and the control electrode; and

[0012] The deforming member deforms the control electrode into different shapes during cleaning by the cleaning member and during charging.

[0013] The invention described in Option 2 is the charging device described in Option 1, wherein the control electrode is tensioned in a direction intersecting with the rotation direction of the charged body, and is maintained in a shape bent or folded along the surface shape of the charged body by a retaining component.

[0014] The invention described in claim 3 is the charging device described in claim 2, wherein during cleaning, the deforming member reduces the tension of the control electrode to deform the control electrode into a shape different from that during charging.

[0015] The invention described in Option 4 is the charging device described in Option 1, wherein at least one end portion of the control electrode along a direction intersecting the rotation direction of the charged body is urged outward relative to the charged area of ​​the charged body by a tensioning member.

[0016] The invention described in Option 5 is the charged device described in Option 4, wherein the deforming member deforms the control electrode into a shape different from that when charged by changing the position of the tensioning part on the other end of the control electrode inward relative to the charged area of ​​the charged body in a direction intersecting with the rotation direction of the charged body.

[0017] The invention described in claim 6 is the charging device described in claim 1, wherein the deforming member changes the shape of the holding portion holding the control electrode from a curved or bent shape to a flat shape.

[0018] The invention described in Option 7 is the charging device described in Option 6, wherein the deformable member has a retaining part that retains one end of the control electrode along a direction intersecting with the rotation direction of the charged body, and the retaining part has: a curved portion that bends or folds the control electrode along the surface shape of the charged body when charged; and a flat portion that deforms the shape of the control electrode into a flat shape different from that when charged when cleaned.

[0019] The invention described in claim 8 is the charging device described in claim 1, wherein during charging, the control electrode is pressed by a restriction member provided on the side of the charged body and thus becomes a shape curved along the surface shape of the charged body.

[0020] The invention described in Option 9 is the charging device described in Option 8, wherein the deformable member deforms the shape of the control electrode into a shape different from that during charging by changing the position of the charging device in a direction away from the charged body.

[0021] The invention described in Scheme 10 is the charging device described in Scheme 1, wherein the deformable member deforms the shape of the control electrode into a shape different from that when charged, and changes the position of the charging device in a direction away from the charged body.

[0022] The invention described in Scheme 11 is the charging device described in Scheme 1, wherein the deforming member deforms the shape of the control electrode into a shape different from that when charged by pressing the two end portions of the control electrode in a direction intersecting the rotation direction of the charged body.

[0023] The invention described in Option 12 is the charging device described in Option 11, wherein the deformable component has a pressing part that presses the two end portions of the control electrode in a direction intersecting with the rotation direction of the charged body, and the pressing part has a pressing portion that deforms the control electrode into a planar shape.

[0024] The invention described in claim 13 is the charging device described in claim 1, wherein the cleaning member cleans both the discharge electrode and the control electrode.

[0025] The invention described in claim 14 is the charging device described in claim 13, wherein the cleaning member has a first cleaning part that contacts the discharge electrode and a second cleaning part that contacts both front and back surfaces of the control electrode deformed into a shape different from that during charging.

[0026] The invention according to claim 15 is an image forming unit including the charging device according to any one of claims 1 to 14, wherein the image forming unit is detachable from the image forming apparatus.

[0027] The invention according to claim 16 is an image forming apparatus comprising:

[0028] Image holding member;

[0029] a charging member for charging the surface of the image holding member; and

[0030] an electrostatic latent image forming member for forming an electrostatic latent image on the surface of the image holding member charged by the charging member,

[0031] The image forming apparatus uses the charging device according to any one of aspects 1 to 14 as the charging member.

[0032] Effects of the Invention

[0033] According to the first aspect of the present invention, compared to cleaning the control electrode while maintaining the same shape as when charged, contact between the control electrode and the surface of the charged object can be avoided, and the cleaning performance of the control electrode can be improved.

[0034] According to the second aspect of the present invention, a planar control electrode can be employed, compared to a case where the control electrode is formed in a curved or bent shape along the surface shape of the charged body without using a holding member.

[0035] According to the third aspect of the present invention, compared to the case where the deforming member applies external force to the control electrode during cleaning to deform it into a shape different from that during charging, the control electrode can be easily deformed into a shape different from that during charging simply by reducing the tension.

[0036] According to the fourth aspect of the present invention, compared to a case where no tension member is used for the control electrode, the structure for applying force to the control electrode outward relative to the charged region of the charged body can be simplified.

[0037] According to the fifth aspect of the present invention, the structure of the tension member becomes simpler compared to the case where the deformation member causes the tension member to change the positions of both end portions of the control electrode.

[0038] According to the sixth aspect of the present invention, the structure of the deforming member becomes simpler compared to a case where the deforming member changes its shape except for the holding portion that holds the control electrode.

[0039] According to the seventh aspect of the present invention, compared to a case where the deforming member includes a curved portion and a flat portion on separate holding members, the shape of the control electrode can be deformed by a single holding member.

[0040] According to the eighth aspect of the present invention, the control electrode can be bent or folded more easily than when the control electrode is bent or folded by restricting members provided on both the charging device and the charged body during charging.

[0041] According to the ninth aspect of the present invention, compared to the case where the deforming member changes the tension of the control electrode, the shape of the control electrode can be easily changed by simply changing the position of the charging member.

[0042] According to the tenth aspect of the present invention, it is possible to clean both the front and back surfaces of the control electrode along the surface shape of the charged object while suppressing the cleaning member from coming into contact with the surface of the charged object.

[0043] According to the eleventh aspect of the present invention, the shape of the control electrode can be reliably deformed compared to a case where the deforming member changes the tension of the control electrode.

[0044] According to the twelfth embodiment of the present invention, the control electrode can be reliably deformed into a planar shape compared to a case where the deformable member does not have parts for pressing the two end portions of the control electrode along the longitudinal direction, that is, a pressing part having a pressing portion for deforming the control electrode into a planar shape.

[0045] According to the thirteenth aspect of the present invention, the structure of the cleaning member can be simplified compared to the case where the cleaning member cleans only the control electrode.

[0046] According to the fourteenth aspect of the present invention, compared with a case where the cleaning member does not include the first cleaning member that contacts the discharge electrode and the second cleaning member that contacts both the front and back surfaces of the control electrode deformed into a shape different from that during charging, it is possible to clean both the discharge electrode and the control electrode.

[0047] According to the 15th embodiment of the present invention, compared with the case where the charging device described in any one of embodiments 1 to 14 is not provided, the cleaning member can be prevented from contacting the surface of the charged body and the front and back surfaces of the control electrode curved along the surface shape of the charged body can be cleaned.

[0048] According to the 16th embodiment of the present invention, compared with the case where the charging device described in any one of embodiments 1 to 14 is not used as the charging component, the cleaning component can be prevented from contacting the surface of the charged body, and the front and back surfaces of the control electrode bent along the surface shape of the charged body can be cleaned. BRIEF DESCRIPTION OF THE DRAWINGS

[0049] Embodiments of the present invention will be described in detail with reference to the following drawings.

[0050] Figure 1 is a diagram showing the overall configuration of an image forming apparatus to which a charging device according to Embodiment 1 of the present invention is applied;

[0051] Figure 2 1 is a structural diagram showing an image forming apparatus according to an image forming apparatus of a first embodiment of the present invention;

[0052] Figure 3 is a perspective structural diagram showing an image forming unit according to Embodiment 1 of the present invention;

[0053] Figure 4 is a perspective structural diagram showing a unit main body of an image forming unit according to Embodiment 1 of the present invention;

[0054] Figure 5 1 is a perspective view showing the structure of a grid electrode of a charging device according to a first embodiment of the present invention;

[0055] Figure 6 is a structural diagram showing a control unit of a grid electrode;

[0056] Figure 7 is a structural diagram showing the connection portion of the grid electrode;

[0057] Figure 8 1 is a perspective structural diagram showing a charging device according to a first embodiment of the present invention;

[0058] Figure 9 1 is a perspective structural diagram showing an insulating block at the rear end of the charging device according to the first embodiment of the present invention;

[0059] Figure 10 1 is a perspective structural diagram showing an insulating block at the front end of the charging device according to the first embodiment of the present invention;

[0060] Figure 11 It is a structural diagram showing the tensioning components;

[0061] Figure 12 It is a cross-sectional structural diagram showing the main parts of the front end insulating block;

[0062] Figure 13 It is a three-dimensional structural diagram showing a cleaning device;

[0063] Figure 14 It is a three-dimensional structural diagram showing a cleaning device;

[0064] Figure 15 It is a three-dimensional structural diagram showing a cleaning device;

[0065] Figure 16 It is a structural diagram showing the swing arm;

[0066] Figure 17 It is a structural diagram showing the swing arm;

[0067] Figure 18 It is a structural diagram showing the action of the tensioning component;

[0068] Figure 19 1 is a perspective structural diagram showing the operation of the charging device according to the first embodiment of the present invention;

[0069] Figure 20 It is a structural diagram showing a cleaning state of a grid electrode by a cleaning device;

[0070] Figure 21 It is a structural diagram showing a cleaning state of a grid electrode by a cleaning device;

[0071] Figure 22 1 is a perspective structural diagram showing the main parts of a charging device according to a second embodiment of the present invention;

[0072] Figure 23 It is a three-dimensional structural diagram showing a retaining component;

[0073] Figure 24 1 is a perspective structural diagram showing the operation of the charging device according to the second embodiment of the present invention;

[0074] Figure 25 This is a front structural diagram showing the operation of the charging device according to the third embodiment of the present invention;

[0075] Figure 261 is a structural diagram showing an image forming apparatus according to a fourth embodiment of the present invention;

[0076] Figure 27 is a schematic structural diagram showing a modified example of the charging device;

[0077] Figure 28 1 is a structural diagram showing a charging device according to a fourth embodiment of the present invention;

[0078] Figure 29 1 is a structural diagram showing a modified example of the charging device according to the fourth embodiment of the present invention;

[0079] Figure 30 It is a structural diagram showing a further modified example of the charging device according to the fourth embodiment of the present invention.

[0080] Explanation of symbols

[0081] 1-image forming device, 12-charging device, 120-shielding case, 121-discharging wire, 122-grid electrode, 125, 126-insulating blocks, 60-tensioning member. DETAILED DESCRIPTION

[0082] Hereinafter, embodiments of the present invention will be described with reference to the accompanying drawings.

[0083] [Implementation Method 1]

[0084] Figure 1 This is a diagram showing the overall outline of an image forming apparatus to which a charging device and an image forming unit according to Embodiment 1 of the present invention are applied.

[0085] <Overall Structure of Image Forming Apparatus>

[0086] The image forming apparatus 1 according to the first embodiment is configured as, for example, a color printer. Figure 1 As shown, the image forming apparatus 1 includes a plurality of imaging devices 10, an intermediate transfer device 20, a paper feeding device 50, and a fixing device 40. The plurality of imaging devices 10 form toner images developed with toner constituting a developer. The intermediate transfer device 20 holds the toner images formed by each imaging device 10 and finally transports them to a secondary transfer position where they are secondary transferred onto a recording paper 5, which is an example of a recording medium. The paper feeding device 50 accommodates and transports the recording paper 5 required to be supplied to the secondary transfer position of the intermediate transfer device 20. The fixing device 40 fixes the toner image on the recording paper 5 that has been secondary transferred in the intermediate transfer device 20. In addition, the double-dashed line in the figure indicates the main transport path for transporting the recording paper 5 within the image forming apparatus 1.

[0087] The image forming apparatus 10 is composed of four image forming devices 10Y, 10M, 10C, and 10K, each specialized for forming toner images of four colors: yellow (Y), magenta (M), cyan (C), and black (K). These four image forming devices 10 (Y, M, C, K) are arranged in a horizontal row within the interior space of the image forming apparatus 1.

[0088] like Figure 2 As shown, each imaging device 10 (Y, M, C, K) includes a rotating photosensitive drum 11 as an example of a charged body and an image holding member. Around the photosensitive drum 11, there are a charging device 12 (Y, M, C, K) as an example of a charging member involved in this embodiment 1, an exposure device 13 (Y, M, C, K) as an example of an electrostatic latent image forming member, a developing device 14 (Y, M, C, K), a primary transfer device 15 (Y, M, C, K) and a drum cleaning device 16 (Y, M, C, K). The charging device 12 charges the peripheral surface (image holding surface) of the photosensitive drum 11 on which an image can be formed to a desired potential. The exposure device 13 irradiates the charged peripheral surface of the photosensitive drum 11 with light based on image information (signal) to form an electrostatic latent image (for each color) with a potential difference. The developing device 14 develops the electrostatic latent image with toners of corresponding colors (Y, M, C, K) to form a toner image. The primary transfer device 15 transfers each toner image to the intermediate transfer device 20. The drum cleaning device 16 removes and cleans toner and other adhering matter remaining on the image holding surface of the photosensitive drum 11 after the primary transfer.

[0089] The photosensitive drum 11 is formed by forming an image holding surface having a photoconductive layer (photosensitive layer) made of a photosensitive material on the circumference of a cylindrical or columnar substrate that has been grounded. The substrate of the photosensitive drum 11 is grounded. The photosensitive drum 11 is supported so as to rotate in the direction indicated by the arrow A as an example of the moving direction by transmitting a driving force from a driving member (not shown). Figure 2 As shown, the surface of the photosensitive drum 11 is curved into a circular shape having a desired curvature radius around the rotation axis.

[0090] The charging device 12 is composed of a so-called scorotron-type charger arranged in a state separated from the photosensitive drum 11. The scorotron-type charging device 12 has a higher charging capacity for the photosensitive drum 11 than a roller-shaped charging roller. Therefore, the scorotron-type charging device 12 is particularly effective in a high-productivity image forming device 1 that increases the rotation speed of the photosensitive drum 11 that determines the processing speed. A charging voltage and a control voltage are supplied to the charging device 12. As the charging voltage, when the developing device 14 performs reverse development, a voltage or current having the same polarity as the charging polarity of the toner supplied from the developing device 14 is supplied. In addition, the structure of the charging device will be described in detail later.

[0091] Exposure device 13 comprises an LED print head. This LED print head utilizes a plurality of LEDs (light emitting diodes) arranged axially of the photosensitive drum 11 to illuminate the photosensitive drum 11 with light corresponding to image information, thereby forming an electrostatic latent image. Alternatively, exposure device 13 may employ an exposure device that deflects and scans a laser beam formed in accordance with image information along the axial direction of the photosensitive drum 11.

[0092] like Figure 2 As shown, the developing devices 14 (Y, M, C, K) are each configured by arranging a developing roller 141, a stirring and supplying member 142, a developer supply roller 143, a stirring and transporting member 144, and a layer thickness limiting member 145 inside a frame 140. The frame 140 is formed with an opening portion at a position opposite to the photosensitive drum 11 and a developer storage chamber therein. The developing roller 141 holds the developer and transports it to a developing area facing the photosensitive drum 11. The stirring and supplying member 142 is composed of an auger or the like, which stirs the developer while supplying it through the developing roller 141. The developer supply roller 143 supplies the developer supplied from the stirring and supplying member 142 to the developing roller 141. The stirring and transporting member 144 is composed of an auger or the like, which stirs the developer while transporting it to the stirring and supplying member 142. The layer thickness limiting member 145 limits the amount (layer thickness) of the developer held on the developing roller 141. In the developing device 14, a developing voltage is supplied from a power supply (not shown) between the developing roller 141 and the photosensitive drum 11. As the developer of the four colors, for example, a two-component developer containing non-magnetic toner and magnetic carrier is used.

[0093] The primary transfer devices 15 (Y, M, C, K) are contact-type transfer devices equipped with primary transfer rollers. These primary transfer rollers rotate while in contact with the periphery of the photoreceptor drum 11 via the intermediate transfer belt 21, and are supplied with a primary transfer voltage. A DC voltage having a polarity opposite to the charged polarity of the toner is supplied as the primary transfer voltage from a power supply (not shown).

[0094] The drum cleaning device 16 is composed of a main body 160, a cleaning brush 161, a cleaning plate 162 and a delivery component 163. A portion of the main body 160 is formed in the shape of an open container. The cleaning brush 161 is configured to contact the peripheral surface of the photosensitive drum 11 after the primary transfer with a required pressure to scrape off residual toner and other attachments and clean them. The cleaning plate 162 is configured to contact the peripheral surface of the photosensitive drum 11 with a required pressure to remove residual toner and other attachments and clean them. The delivery component 163 is composed of a spiral conveyor and the like, which recovers the toner and other attachments removed by the cleaning brush 161 and the cleaning plate 162 and delivers them to a recovery system not shown in the figure. As the cleaning plate 162, a plate-shaped component (such as a scraper) made of a material such as rubber is used.

[0095] An antistatic lamp 17 is disposed between the drum cleaning device 16 and the charging device 12. The antistatic lamp 17 evenly exposes the surface of the photosensitive drum 11 from which residual toner and other attached substances have been removed by the drum cleaning device 16, thereby eliminating static electricity.

[0096] like Figure 1 As shown, the intermediate transfer device 20 is located vertically below each imaging device 10 (Y, M, C, K). The intermediate transfer device 20 primarily comprises an intermediate transfer belt 21, a plurality of belt support rollers 22-24, a secondary transfer device 30, and a belt cleaning device 25. The intermediate transfer belt 21 rotates in the direction indicated by arrow B while passing through the primary transfer position between the photosensitive drum 11 and the primary transfer device 15 (primary transfer rollers). The plurality of belt support rollers 22-24 rotatably support the intermediate transfer belt 21 while maintaining the desired state from its inner surface. The secondary transfer device 30 is located on the outer peripheral surface (image holding surface) of the intermediate transfer belt 21 supported by the belt support rollers 24, so as to perform a secondary transfer of the toner image on the intermediate transfer belt 21 onto the recording paper 5. The belt cleaning device 25 removes and cleans any residual toner, paper dust, and other adhering matter that remains on the outer peripheral surface of the intermediate transfer belt 21 after passing through the secondary transfer device 30.

[0097] The intermediate transfer belt 21 is, for example, an endless conveyor belt made of a material obtained by dispersing a resistance modifier such as carbon black in a synthetic resin such as a polyimide resin or a polyamide resin. The belt support roller 22 is a drive roller that is rotationally driven by a drive device (not shown). The belt support roller 23 is a surface smoothing roller that maintains the image forming surface of the intermediate transfer belt 21. The belt support roller 24 is an opposing roller that faces the secondary transfer device 30. The belt support roller 22 also serves as a support roller for the back surface of the belt cleaning device 25.

[0098] like Figure 1 As shown, the secondary transfer device 30 is a contact-type transfer device equipped with a secondary transfer roller 31. The secondary transfer roller 31 rotates while in contact with the circumference of the intermediate transfer belt 21 at the secondary transfer position, which is the outer circumference of the intermediate transfer belt 21 supported by the belt support roller 24 in the intermediate transfer device 20. A DC voltage having a polarity opposite to or the same as the charged polarity of the toner is supplied as the secondary transfer voltage from a power supply (not shown) to the secondary transfer roller 31 or the belt support roller 24 of the intermediate transfer device 20.

[0099] The fixing device 40 is constructed by arranging a heating rotating body 42 and a pressurizing rotating body 43 inside a frame 41. An inlet and an outlet for the recording paper 5 are formed on the frame 41. The heating rotating body 42 is formed in a belt form or a roller form that rotates in the direction indicated by the arrow and is heated by a heating member so that the surface temperature is maintained at a predetermined temperature. The pressurizing rotating body 43 is formed in a roller form or a belt form that contacts and rotates driven by the heating rotating body 42 at a predetermined pressure in a state roughly along the axial direction. In the fixing device 40, the contact portion between the heating rotating body 42 and the pressurizing rotating body 43 becomes a fixing nip portion N that performs the required fixing process (heating and pressurization).

[0100] The paper feed device 50 is located below the intermediate transfer device 20. It primarily consists of a single (or multiple) paper container 51 and feed devices 52 and 53. The paper container 51 holds recording paper 5 of a desired size and type. The feed devices 52 and 53 feed recording paper 5 one sheet at a time from the paper container 51. The paper container 51 is configured to be drawn out, for example, toward the front of the device (the side facing the user during operation).

[0101] Examples of the recording paper 5 include plain paper, thin paper such as tracing paper, and OHP sheets used in electrophotographic copiers and printers. To further improve the smoothness of the image surface after fixing, the surface of the recording paper 5 is preferably as smooth as possible. For example, coated paper, which is plain paper coated with a resin or the like, or thick paper with a relatively high basis weight, such as coated printing paper, can also be preferably used.

[0102] A plurality of or a single paper transport roller pairs 54, 55 and a paper transport path 56 are provided between the paper feed device 50 and the secondary transfer device 30. The paper transport roller pairs 54, 55 transport the recording paper 5 fed from the paper feed device 50 to the secondary transfer position. The paper transport path 56 is composed of a transport guide device (not shown). The paper transport roller pair 55, which is arranged immediately before the secondary transfer position on the paper transport path 56, is configured as, for example, a roller (registration roller) for adjusting the transport timing of the recording paper 5. Furthermore, a plurality of or a single paper transport roller pairs 57, 58 or a paper transport path 59 are provided between the secondary transfer device 30 and the fixing device 40 for transporting the recording paper 5 fed from the secondary transfer device 30 to the fixing device 40 after the secondary transfer. In addition, a paper discharge portion (not shown) for discharging the fixed recording paper 5 fed from the fixing device 40 is provided on the side of the image forming device 1.

[0103] Furthermore, the image forming apparatus 1 may include a double-sided paper conveying path (not shown) for forming images on both sides of the recording paper 5 .

[0104] exist Figure 1 In the figure, reference numeral 100 denotes a control device that centrally controls the operation of the image forming apparatus 1. The control device 100 includes a CPU (Central Processing Unit), ROM (Read Only Memory), RAM (Random Access Memory), a bus connecting the CPU and ROM, and a communication interface, etc. (not shown).

[0105] <Structure of the Image Forming Unit>

[0106] like Figure 2 As shown, the image forming apparatus 1 according to the first embodiment includes multiple image forming units 200 corresponding to the respective imaging devices 10 (Y, M, C, K) to improve maintainability, etc. Each image forming unit 200 is constructed by integrating multiple components, including at least the photosensitive drum 11, from among the components constituting the yellow (Y), magenta (M), cyan (C), and black (K) imaging devices 10 (Y, M, C, K). Each image forming unit 200 is individually attachable to and detachable from the image forming apparatus 1.

[0107] In this embodiment 1, as Figure 2 As shown, the photosensitive drum 11, the charging device 12, and the drum cleaning device 16 are integrally formed into an image forming unit 200. Alternatively, the charging device 12 can be configured to be independently attachable and detachable from the photosensitive drum 11 and the drum cleaning device 16. The image forming unit 200 is replaced with a new component when components such as the photosensitive drum 11 reach the end of their life, or when the charging device 12 or the drum cleaning device 16 malfunction. When the image forming unit 200 does not include the developing device 14, a common image forming unit 200 can be used for all imaging devices 10 (Y, M, C, K).

[0108] like Figure 3 As shown, the image forming unit 200 includes a unit body 201. The unit body 201 includes: front and rear support parts 202, 203, which rotatably support both ends of the photosensitive drum 11 in the axial direction; and a connecting part 204, which connects the front and rear support parts 202, 203 to one side surface of the photosensitive drum 11. Figure 4 As shown, the front and rear support parts 202 and 203 are provided with front and rear positioning parts 205 and 206 for positioning the two ends along the longitudinal direction of the charging device 12. The front and rear positioning parts 205 and 206 are respectively opened with positioning holes 205a, 205b and 206a, 206b for positioning the charging device 12.

[0109] The front and rear support sections 202 and 203 of the unit body 201 are provided with curved sections 207 and 208. These curved sections 207 and 208 support the grid electrode 122 of the charging device 12 in a curved shape that follows the surface of the photosensitive drum 11 when the charging device 12 is attached. The curved sections 207 and 208 are formed into arcuate shapes that protrude a desired distance from the surface of the photosensitive drum 11, which is rotatably mounted on the image forming unit 200. The height of the curved sections 207 and 208 determines the gap (DGS) between the surface of the photosensitive drum 11 and the grid electrode 122 of the charging device 12.

[0110] Furthermore, the connecting portion 204 of the unit body 201 also serves as the main body 160 of the drum cleaning device 16. Furthermore, a drive shaft 209 is rotatably mounted on the upper portion of the charging device 12. This drive shaft 209 drives the cleaning device 70 (described later) in the axial direction of the photosensitive drum 11 to clean the charging device 12. A helical protrusion 209a with a large pitch is provided on the outer circumference of the drive shaft 209. An adapter portion 209b is provided at the inner end of the drive shaft 209 in the axial direction. This adapter portion 209b transmits driving force from the image forming device 1 when the image forming unit 200 is mounted on the image forming device 1.

[0111] The image forming unit 200 is configured to be insertable and removable from an opening provided on the front face of the image forming apparatus 1 (not shown) along a depth direction intersecting the width direction of the image forming apparatus 1 with the front cover (not shown) of the image forming apparatus 1 open.

[0112] <Operation of Image Forming Apparatus>

[0113] Hereinafter, a basic image forming operation by the image forming apparatus 1 will be described.

[0114] Here, the operation in the full-color mode for forming a full-color image composed of a combination of toner images of four colors (Y, M, C, K) using the four image forming devices 10 (Y, M, C, K) will be described.

[0115] If the image forming device 1 receives image information and instruction information requesting a full-color image forming action (printing) from a personal computer or image reading device (not shown), the control device 100 starts four imaging devices 10 (Y, M, C, K), an intermediate transfer device 20, a secondary transfer device 30, a fixing device 40, etc.

[0116] Moreover, if Figure 1 As shown, in each imaging device 10 (Y, M, C, K), first, each photosensitive drum 11 rotates in the direction indicated by the arrow A, and each charging device 12 charges the surface of each photosensitive drum 11 to the required polarity (negative polarity in embodiment 1) and potential.

[0117] Next, the exposure device 13 irradiates the charged surface of the photosensitive drum 11 with light according to the image signal converted into each color component (Y, M, C, K), thereby forming an electrostatic latent image of each color component having a desired potential difference on the surface.

[0118] Next, each developing device 14 (Y, M, C, K) supplies a toner of the corresponding color (Y, M, C, K) charged to a desired polarity (negative polarity) from the developing roller 141 to the electrostatic latent image of each color component formed on the photosensitive drum 11, causing electrostatic adhesion and development. Through this development, the electrostatic latent image of each color component formed on each photosensitive drum 11 is visualized as a toner image of four colors (Y, M, C, K) developed by the toner of the corresponding color.

[0119] Next, if the color toner images of each color formed on the photosensitive drum 11 of each imaging device 10 (Y, M, C, K) are transferred to the primary transfer position, the primary transfer device 15 (Y, M, C, K) transfers the color toner images of each color in a state of sequentially overlapping with the intermediate transfer belt 21 of the intermediate transfer device 20 that rotates in the direction indicated by the arrow B.

[0120] After the primary transfer is completed, the drum cleaning device 16 of each imaging device 10 (Y, M, C, K) scrapes away the attached matter and cleans the surface of the photosensitive drum 11. This allows each imaging device 10 (Y, M, C, K) to be ready for the next imaging operation.

[0121] Next, the intermediate transfer device 20 holds the toner image, which has been primarily transferred by the rotation of the intermediate transfer belt 21, and transports it to the secondary transfer position. Meanwhile, the paper feed device 50 delivers the required recording paper 5 to the paper feed path 56 in conjunction with the image formation operation. On the paper feed path 56, a paper feed roller pair 55, serving as registration rollers, delivers the recording paper 5 to the secondary transfer position in conjunction with the transfer timing.

[0122] At the secondary transfer position, the secondary transfer device 30 secondary transfers the toner image on the intermediate transfer belt 21 onto the recording paper 5. After the secondary transfer is completed, the belt cleaning device 25 in the intermediate transfer device 20 removes and cleans toner and other attached materials remaining on the surface of the intermediate transfer belt 21 after the secondary transfer.

[0123] Next, the recording paper 5, to which the toner image has been secondary transferred, is peeled from the intermediate transfer belt 21 and conveyed to the fixing device 40 via the paper conveying path 59. In the fixing device 40, the recording paper 5 after the secondary transfer is introduced into the contact portion between the rotating heating rotator 42 and the pressing rotator 43 and passed through, where it undergoes the necessary fixing process (heating and pressing) to fix the unfixed toner image onto the recording paper 5. Finally, the recording paper 5 after the fixing process is discharged, for example, to a paper discharge portion provided on the side of the device main body (not shown).

[0124] Through the above-described operation, the recording paper 5 on which a full-color image formed by combining the toner images of four colors is output.

[0125] <Structure of the live device>

[0126] like Figure 2 and Figure 3 As shown, the charging device 12 according to the first embodiment is arranged along the axial direction of the photosensitive drum 11, which is an example of a direction intersecting the rotational direction A of the photosensitive drum 11. Here, the axial direction of the photosensitive drum 11 is the longitudinal direction of the charging device 12. Figure 3 In the figure, symbol L represents the longitudinal direction of the charging device 12 , symbol W represents the width direction of the charging device 12 , and symbol H represents the height direction of the charging device 12 .

[0127] In addition, Figure 3, the charging device 12 is shown as being positioned directly above the photosensitive drum 11, with the height direction H of the charging device 12 aligned with the vertical direction. However, the charging device 12 is not limited to being positioned directly above the photosensitive drum 11; it may also be positioned at an angle along the circumference of the photosensitive drum 11. In this case, the height direction H of the charging device 12 differs from the vertical direction.

[0128] like Figure 2 As shown, the charging device 12 generally includes a shield case 120 as an example of a housing, a single or multiple (two in the illustrated example) discharge wires 121, 121 as an example of a discharge electrode, and a grid electrode 122 as an example of a control electrode.

[0129] The shielding shell 120 is made of a metal such as stainless steel or aluminum. The shielding shell 120 functions as a counter electrode when a high voltage is applied to the discharge wires 121, 121 to generate a corona discharge. The shielding shell 120 is formed into a rectangular parallelepiped shape elongated along the axial direction of the photosensitive drum 11, with an opening 123 open throughout the surface facing the photosensitive drum 11 (the lower surface in the figure). The shielding shell 120 includes a top wall 120a, left and right side walls 120b, 120c, and a partition wall 120d. The top wall 120a is located at the upper end on the side opposite to the photosensitive drum 11. The left and right side walls 120b, 120c are arranged in a state of being bent from both ends along the width direction of the top wall 120a toward the bottom facing the photosensitive drum 11. The partition wall 120d partitions the space within the shielding shell 120 along the rotational direction A of the photosensitive drum 11, i.e., the width direction, according to the number of discharge wires 121, 121. When there is only one discharge wire 121, partition wall 120d is not provided. When there are three or more discharge wires 121, partition walls 120d are provided to separate the discharge wires 121, 121, ... . Furthermore, shield case 120 is applied with the same high voltage as grid electrode 122 or is grounded. The cylindrical or columnar conductive substrate of photoconductive drum 11 is grounded.

[0130] The shield case 120 has a top wall 120a with an air outlet 120e extending along its entire length in the longitudinal direction. The air outlet 120e blows air toward the surface of the photosensitive drum 11, thereby removing discharge products such as ozone generated by corona discharge.

[0131] The discharge wires 121, 121 are made of tungsten, tungsten carbide, gold-plated tungsten, etc. A negative high voltage of several K to approximately 8 KV is applied to the discharge wires 121, 121 by a high voltage power supply (not shown), for example.

[0132] Grid electrode 122 is disposed in an opening 123 of shield case 120 that faces photosensitive drum 11, curved in an arc shape along the surface of photosensitive drum 11. To achieve a desired charge potential on photosensitive drum 11, a high voltage substantially equal to the desired potential is applied to grid electrode 122 by, for example, a high-voltage power supply (not shown).

[0133] like Figure 5 As shown, grid electrode 122 is formed into a slender, rectangular, flat plate corresponding to opening 123 of shield case 120 by etching or stamping a thin plate-like member made of a metal such as tungsten, tungsten carbide, or gold-plated tungsten. Grid electrode 122 integrally includes a control portion 122a and connecting portions 122b and 122c. Control portion 122a extends over the entire length of grid electrode 122, excluding both ends. Connecting portions 122b and 122c are provided at both ends of control portion 122a. Short, strip-shaped boundary portions 122d are provided between control portion 122a and connecting portions 122b and 122c, respectively, along the length. Control portion 122a of grid electrode 122 has slightly wider, strip-shaped edge portions 122e and 122e at both ends of its width. Furthermore, the control portion 122a is divided into sections by a band-shaped section 122f having a center portion in the width direction that is narrower than the end edges 122e, 122e.

[0134] like Figure 6 (a)~ Figure 6 As shown in (c), as the control part 122a of the grid electrode 122, there can be used: a grid electrode in which fine mesh-shaped or narrow straight-line conductors along the long side direction are arranged parallel to each other in the width direction; or a grid electrode in which narrow straight-line conductors inclined in a direction intersecting the long side direction are arranged parallel to each other, and fine gaps are uniformly formed along the long side direction and the width direction.

[0135] The control unit 122a of the grid electrode 122 controls as follows: charged particles such as ions generated by corona discharge caused by applying a high voltage to the discharge wires 121, 121 pass through the gaps formed between mesh-shaped or narrow linear conductors and adhere to the surface of the photosensitive drum 11 to be charged, and the charged potential of the photosensitive drum 11 is controlled by the action of the electric field formed by the voltage applied to the control unit 122a.

[0136] like Figure 5As shown, the connecting portions 122b and 122c of the grid electrode 122 are constructed by extending an even number (eight in the illustrated example) of linear, thin connecting pieces 122b' and 122c' parallel to each other from the longitudinal ends of the control portion 122a, across a boundary portion 122d, toward the longitudinal ends. The connecting portions 122b and 122c are constructed by forming a ring-shaped connection between two adjacent connecting pieces 122b' and 122c'. Furthermore, in the illustrated example, the connecting pieces 122b" and 122c" at the widthwise ends are bent inward from midway along the longitudinal direction.

[0137] In addition, as the connecting portions 122b and 122c of the grid electrode 122, the following connecting portions can be used: Figure 7 As shown in (a), two connecting portions 122b, 122b can be extended from both ends along the width direction toward the center of the front end along the longitudinal direction, and the front ends of the two connecting portions 122b, 122b can be connected to form a "コ" shape, and an opening portion 122g for locking a locking claw (not shown) can be provided; or as shown in Figure 7 As shown in (b), it extends in a wide belt shape toward the front end along the longitudinal direction, and is provided with elongated openings 122h, 122h for connection in the width direction at its front end.

[0138] However, if Figure 5 As shown, when the connection parts 122b and 122c of the grid electrode 122 are formed by connecting the front ends of an even number of connection pieces 122b' and 122c' arranged parallel to each other in the width direction to each other in a ring shape, it is preferable to enable tension to be applied approximately uniformly in the width direction of the grid electrode 122.

[0139] like Figure 5 As shown, the free shape of the grid electrode 122 when no tension is applied along the longitudinal direction is a flat plate shape. Therefore, when the tension is released or reduced, the grid electrode 122 returns to the free shape, ie, the flat plate shape, due to its own elastic restoring force.

[0140] If the structure of the charging device 12 is further described, Figure 8 As shown, the charging device 12 includes a guide member 124, front and rear insulating blocks 125 and 126, and a mounting member 127. The guide member 124 is provided on the side of the shield case 120 opposite the photosensitive drum 11 (the lower surface in the figure) along the longitudinal direction. The front and rear insulating blocks 125 and 126 are respectively arranged at the ends of the shield case 120 along the longitudinal direction. The mounting member 127 is provided at the end near the front of the front insulating block 125, which is arranged on the front side of the image forming apparatus 1.

[0141] The guide member 124 is formed of a synthetic resin or the like into a slender, flat plate. Two guide protrusions 124a and 124b are provided on the outer side of the guide member 124 at either end along its longitudinal direction to guide the charging device 12 when it is mounted on the image forming apparatus 1. The two guide protrusions 124a and 124b are formed so that the guide protrusion 124b located on the back side of the image forming apparatus 1 is longer than the guide protrusion 124a located on the front side of the image forming apparatus 1.

[0142] The front and rear insulating blocks 125 and 126 are composed of a single or multiple insulating components made of synthetic resin. These blocks are secured to the longitudinal ends of the shielding case 120 using methods such as snap-fitting. Two discharge wires 121 and 121 and a grid electrode 122 are tensioned across these blocks. One end of each discharge wire 121 is secured to one of the blocks 126, while the other end is secured to the other insulating block 125 by applying the desired tension to the other insulating block 125 via an elastic member such as a coil spring.

[0143] like Figure 9 As shown, the rear insulating block 126 is provided with a curved retaining portion 126a that deforms the rear end of the grid electrode 122 into a curved shape that conforms to the surface of the photosensitive drum 11 for retention; and multiple latching claws 126b, 126b, etc., that latch and secure the connecting portion 122c of the grid electrode 122. Furthermore, a semi-cylindrical and rectangular cylindrical conducting portion 126c is provided at the front end of the rear insulating block 126. This conducting portion 126c incorporates multiple conducting electrodes (not shown) for respectively conducting electricity to the shield case 120, the discharge wire 121, and the grid electrode 122. When the charging device 12 is mounted on the image forming apparatus 1, the conducting portion 126c of the rear insulating block 126 connects to electrodes on the image forming apparatus 1 side, enabling electricity to be supplied to the shield case 120, the discharge wire 121, and the grid electrode 122.

[0144] In the rear end insulating block 126, positioning pins 126d, 126d are provided at both ends in the width direction so as to protrude toward the inner side in the longitudinal direction. These positioning pins 126d, 126d position the rear end of the charging device 12 when the charging device 12 is mounted on the image forming apparatus 1. Figure 4 As shown, the positioning pins 126 d and 126 d of the rear insulating block 126 are engaged with the positioning holes 206 a and 206 b of the positioning portion 206 provided in the support portion 203 at the rear end of the image forming unit 200 , thereby positioning the charging device 12 .

[0145] like Figure 10As shown, the front-end insulating block 125 is provided with a curved retaining portion 125a that deforms the front end of the grid electrode 122 into a curved shape that conforms to the surface of the photosensitive drum 11 for retention; and a tensioning member 60 that secures the connecting portion 122b of the grid electrode 122 in a locked state. The tensioning member 60 applies tension to the connecting portion 122b of the grid electrode 122 by displacing it outward relative to the charged region of the grid electrode 122. The tensioning member 60 is mounted on the front-end insulating block 125 so as to be rotatable about a rotation axis extending along the width direction W of the charging device 12.

[0146] like Figure 12 As shown, the retaining portions 125a and 126a of the insulating blocks 125 and 126 and the curved portions 207 and 208 of the image forming unit 200 are arranged so as to slightly protrude toward the other component relative to the tensioned position of the grid electrode 122. As a result, the shape and position of the grid electrode 122 are determined by the curved portions 207 and 208 of the image forming unit 200.

[0147] like Figure 10 As shown, the insulating block 125 at the front end is provided with a rising wall 125d, and an insertion hole 125c is opened on the rising wall 125d for the connection portion 122b of the grid electrode 122 to pass through. In addition, positioning pins 125e, 125e (see FIG. 1 ) are provided on the rising wall 125d of the insulating block 125 along the width direction of the upper portion of the insertion hole 125c. Figure 8 ) are provided in a manner protruding toward the charged area of ​​the photosensitive drum 11 along the longitudinal direction L, and the positioning pins 125e, 125e position the front end portion of the charging device 12 when the charging device 12 is mounted on the image forming apparatus 1. Figure 4 As shown, the charging device 12 is positioned by fitting positioning pins 125 e , 125 e of the front end insulating block 125 into positioning holes 205 a , 205 b of the positioning portion 205 provided on the support portion 202 at the front end of the image forming unit 200 .

[0148] like Figure 11As shown, the tensioning member 60 provided at the front end of the insulating block 125 is formed by stamping or bending a metal plate made of a metal such as stainless steel, or by integrally molding a synthetic resin. The tensioning member 60 includes a main body 601 having a front face formed into a rectangular shape extending horizontally along the width direction W of the charging device 12; a plurality of locking claws 602, 602, ... provided at the upper end of the main body 601 at desired intervals so as to protrude upward; pivot supports 603, 603 bent orthogonally from both ends of the main body 601 along the width direction; and a connecting portion 604 bent at the lower end of the main body 601 in the same direction as the pivot supports 603, 603 and connected to one end of a coil spring 605, an example of a biasing member.

[0149] Regarding the locking claws 602, 602, ... of the tensioning member 60, as shown in FIG. Figure 11 As shown in (a), the locking claws 602, 602 at both ends in the width direction are arranged close to the grid electrode 122 so as to be approximately equidistant from the connecting pieces 122b', 122b" of the connecting portion 122b of the grid electrode 122 arranged in a curved shape.

[0150] The pivot support portions 603, 603 of the tension member 60 are provided with rotation shafts 603a, 603a so as to protrude toward both ends in the width direction. Figure 12 As shown, the rotation shafts 603a, 603a of the tension member 60 are rotatably supported by a pivot support portion 125f provided inside the insulation block 125 at the front end.

[0151] like Figure 12 As shown, one end of a coil spring 605 is connected to the connecting portion 604 of the tensioning member 60. The other end of the coil spring 605 is fixed inside the insulating block 125. As a result, the tensioning member 60 is biased counterclockwise in the figure. The grid electrode 122, which is engaged with the engaging claws 602, 602, etc. of the tensioning member 60, is subjected to tension by the coil spring 605.

[0152] The mounting member 127 of the charging device 12 is a member for mounting the charging device 12 in a fixed state when the charging device 12 is mounted on the image forming apparatus 1. Figure 12 As shown, a fixed arm 127a, which is biased counterclockwise by a spring 127b, is rotatably mounted on the mounting member 127. The charging device 12 is released from the image forming apparatus 1 by manually grasping a release lever (not shown) provided on the mounting member 127 to rotate the fixed arm 127a clockwise.

[0153] <Structure of the cleaning device for live equipment>

[0154] The charging device 12 according to the first embodiment includes a cleaning device 70 as an example of a cleaning member, which cleans at least the discharge electrode and the control electrode. The cleaning device 70 according to the first embodiment cleans both the two discharge wires 121 and the grid electrode 122 .

[0155] like Figure 13 As shown, when the charging device 12 is charged, the cleaning device 70 waits at a waiting position set at one end of the charging device 12 along the longitudinal direction of the shield case 120 , that is, at the rear end on the side of the insulating block 126 .

[0156] Figure 14 This is a perspective structural diagram of the long strip-shaped charging device 12 with the cleaning device 70 installed, viewed from the front end side toward the rear end side along the longitudinal direction. Figure 14 The state in which the grid electrode 122 is deformed into a planar shape during cleaning is shown.

[0157] like Figure 15 As shown, the cleaning device 70 includes an upper body 71 and a lower body 72. The upper body 71 is formed into a frame-like shape with a downwardly facing rectangular cross section and an open lower end surface. The lower body 72 is formed into a frame-like shape with a lower rectangular cross section and a lower height lower than the upper body 71 and an open lower end surface. The lower body 72 is integrally provided so as to be fitted into the lower end portion of the upper body 71.

[0158] like Figure 14 As shown, the upper body 71 has an upper end portion 710 corresponding to the top wall 120a of the shield shell 120, and left and right side portions 711 and 712 corresponding to the left and right side walls 120b and 120c of the shield shell 120. The upper end portion 710 of the upper body 71 has guide ridges 710a at both ends along the width direction thereof, which guide the top wall 120a of the shield shell 120. Furthermore, the left and right side portions 711 and 712 of the upper body 71 have short guide ridges 711a and 712a at both ends along the longitudinal direction thereof, which guide the left and right side walls 120b and 120c of the shield shell 120, respectively.

[0159] like Figure 15 As shown, the upper end portion 710 of the upper body 71 is provided with: left and right support plates 714, 715, which are arranged to protrude in parallel with each other and face each other upward with a gap 713 in the center along the width direction; and a cylindrical drive portion 716, which is arranged horizontally on the upper portions of the left and right support plates 714, 715. A spiral groove (not shown) is formed inside the drive portion 716 to engage with the spiral protrusion 209a of the drive shaft 209. Figure 14As shown, the left and right support plates 714 and 715 protrude toward the upper portion of the top wall 120 a through the air outlet 120 e opened in the top wall 120 a of the shield case 120 .

[0160] like Figure 15 As shown, left and right guide plates 717 and 718 are provided on the outer side surfaces of the left and right support plates 714 and 715 of the upper body 71 so as to protrude horizontally outward. The left and right guide plates 717 and 718 have guide ridges 717a and 718a provided on the lower surfaces of their front ends, respectively, for guiding the top wall 120a of the shielding case 120.

[0161] A swing arm 73 that holds a cleaning member is housed inside the upper body 71. The swing arm 73 is swingably attached to the left and right side surfaces 711 and 712 of the upper body 71 via rotation shafts 731 and 732.

[0162] like Figure 16 and Figure 17 As shown, the swing arm 73 integrally includes left and right horizontal plates 733 and 734, a connecting plate 735, and left and right mounting plates 736 and 737. The left and right horizontal plates 733 and 734 of the swing arm 73 are arranged to span the partition wall 120d of the shield case 120, dividing the left and right sides in the horizontal direction. Rotating shafts 731 and 732 that swingably support the swing arm 73 are provided at the horizontal front ends of the left and right horizontal plates 733 and 734. As described above, the rotating shafts 731 and 732 of the swing arm 73 are rotatably supported by insertion holes provided in the left and right side surfaces 711 and 712 of the upper body 71.

[0163] The connecting plate portion 735 of the swing arm 73 is formed as a rectangular frame that is elongated and downwardly oriented from the center ends of the left and right horizontal plate portions 733 and 734 in the width direction toward the upper side in the vertical direction. Figure 14 As shown, the connecting plate portion 735 of the swing arm 73 connects the left and right horizontal plate portions 733 and 734 in a state of straddling the partition wall 120 d of the shield case 120 .

[0164] The mounting plates 736 and 737 of the swing arm 73 extend horizontally from the center ends of the left and right horizontal plates 733 and 734 in the width direction. Cleaning pads 738 and 739, serving as an example of a cleaning member, are mounted on the mounting plates 736 and 737 of the swing arm 73 to clean the two discharge wires 121 and 121 from above. The cleaning pads 738 and 739 are made of a member such as felt or sponge.

[0165] Working portions 736a and 737a are positioned at the opposing lower ends of the connecting plate portion 735 of the swing arm 73, projecting downward. The swing arm 73 is wound around the outer periphery of the rotating shafts 731 and 732 and is positioned along the outer periphery of the connecting plate portion 735. This is thereby biased counterclockwise by a coil spring 740 integrally formed on the left and right sides. The front end of the coil spring 740, wound around the outer periphery of the rotating shafts 731 and 732, abuts against a portion of the upper body 71, generating a counterclockwise force. Therefore, during cleaning, the swing arm 73 rotates counterclockwise due to the force of the coil spring 740, causing the cleaning pads 738 and 739 to press against the cleaning pads provided on the lower body 72, thereby cleaning the two discharge wires 121 and 121.

[0166] On the other hand, Figure 14 As shown, when not cleaning, with the cleaning device 70 in the standby position, the swing arm 73 is stopped. The operating portion 736a, 737a provided at the lower end of the mounting plate portions 736, 737 is pressed against the operating arm of the insulating block 126 at the rear end, causing the swing arm 73 to rotate clockwise. Consequently, the swing arm 73 rotates clockwise against the force of the coil spring 740, separating the cleaning pads 738, 739 from the two discharge wires 121, 121. At this time, the cleaning pad provided on the lower body 72 is also separated from the two discharge wires 121, 121.

[0167] The lower body 72 includes an upper end surface 720 disposed at the lower end of the upper body 71 and wider than the upper body 71 , and left and right side surfaces 721 and 722 extending downward from both ends of the upper end surface 720 in the width direction.

[0168] On the upper end surface 720 of the lower body 72, left and right vertical plate portions 723 and 724 are provided near both ends in the width direction, protruding upward in the vertical direction. On the outer side surfaces of the left and right vertical plate portions 723 and 724 of the lower body 72, two protrusions 725 and 725 for engaging and fixing with the upper body 71 are provided along the longitudinal direction. The protrusions 725 and 725 of the left and right vertical plate portions 723 and 724 are engaged and fixed in the insertion holes provided in the left and right side portions 711 and 712 of the upper body 71 (refer to FIG. Figure 15 ).

[0169] Cleaning pads 726 and 727 are fixed to the upper end surface 720 of the lower body 72 at positions opposite cleaning pads 738 and 739, respectively, of the upper body 71. The cleaning pads 726 and 727 of the lower body 72 are arranged slightly apart from the two discharge wires 121, 121. Furthermore, a wide cleaning pad 728 is provided on the lower surface of the upper end surface 720 of the lower body 72 for cleaning the grid electrode 122. The cleaning pad 728 is formed of a material such as felt or sponge.

[0170] Support plates 729 and 730 are provided on the inner sides of the lower ends of the left and right side surfaces 721 and 722 of the lower body 72, facing inward in the width direction. These plates support the width ends of the grid electrode 122 during cleaning. The upper end surfaces of the support plates 729 and 730 are flat.

[0171] However, the charging device 12 configured as described above is arranged such that the grid electrode 122 is curved in an arc shape along the surface of the photosensitive drum 11. Consequently, there are technical problems: during cleaning by the cleaning pad 728 of the cleaning device 70, the grid electrode 122 of the charging device 12 is pressed by the cleaning pad 728 and comes into contact with the surface of the photosensitive drum 11, or it becomes difficult to ensure that the cleaning pad 728 uniformly contacts the entire surface of the curved grid electrode 122, thereby reducing cleaning performance. Furthermore, uneven contamination of the grid electrode 122 may cause variations in the charged potential of the photosensitive drum 11.

[0172] Therefore, the charging device according to the first embodiment is configured to include a deforming member that deforms the shape of the control electrode into a shape different from that during charging when the cleaning member performs cleaning.

[0173] Furthermore, the charging device according to the first embodiment is configured as follows: the control electrode is stretched with tension applied in a direction intersecting the rotation direction of the charged body, and is held by a holding member in a shape bent or folded along the surface shape of the charged body.

[0174] Furthermore, the charging device according to the first embodiment is configured such that during cleaning, the deforming member reduces the tension of the control electrode, thereby deforming the control electrode into a shape different from that during charging.

[0175] Furthermore, the charging device according to the first embodiment is configured such that at least one end portion of the control electrode in a direction intersecting the rotational direction of the charged body is urged outward relative to the charged region of the charged body by a tension member.

[0176] Furthermore, the charging device involved in this embodiment 1 is constructed as follows: the deforming member deforms the control electrode into a shape different from that when charged by changing the position in which the tensioning part tensions the other end of the control electrode inward relative to the charged area of ​​the charged body along a direction intersecting with the rotation direction of the charged body.

[0177] That is, Figure 10 As shown, the charging device 12 according to the first embodiment includes a tension member 60 that applies tension to a connecting portion 122 b located at one end portion of the grid electrode 122 in the longitudinal direction L and constitutes a part of a deforming member.

[0178] like Figure 11 As shown in (b), an eccentric cam 80 as an example of a deformable member is arranged on the tensioning member 60. The eccentric cam 80 is rotationally driven by a small drive motor (not shown) provided in the charging device 12 or by rotating an operating lever (not shown) provided in the mounting member 127. In addition, the eccentric cam 80 can also be configured to transmit a driving force from the image forming unit 200 side. If the eccentric cam 80 is rotationally driven and the eccentric portion 81 abuts against the main body 601 of the tensioning member 60, the main body 601 rotates the tensioning member 60 in the clockwise direction around the rotating shaft 603a and against the force of the coil spring 605.

[0179] Then, the grid electrode 122, which is locked in the locking claws 602, 602, ... of the tensioning member 60, is tensioned by the insulating block 125 at the front end, and the tension position thereof is changed toward the charging area along the longitudinal direction L of the charging device 12, and the tension of the grid electrode 122 is released or reduced. Figure 5 As shown, the grid electrode 122 is deformed into a flat plate shape by its own elastic restoring force.

[0180] <Function of the live device>

[0181] As described below, in the charging device according to the first embodiment, compared with cleaning the control electrode while maintaining the same shape as during charging, contact between the control electrode and the surface of the charged object can be avoided and the cleaning performance of the control electrode can be improved.

[0182] like Figure 1 As shown, in the image forming device 1, based on the cumulative image formation time in each imaging device 10 (Y, M, C, K) of yellow (Y), magenta (M), cyan (C) and black (K), the cumulative number of printed sheets of recording paper 5, etc., the cleaning device 70 performs the cleaning action of cleaning the discharge wires 121, 121 and the grid electrode 122 of the charging device 12 at a preset time.

[0183] In the charging device 12 , during cleaning, before the cleaning operation by the cleaning device 70 , an operation is performed to deform the shape of the grid electrode 122 into a flat plate shape, which is an example of a shape different from that during charging.

[0184] like Figure 18 As shown, the charging device 12 rotates the eccentric cam 80 in the clockwise direction via a drive motor or solenoid (not shown) or by operating a release lever provided on the mounting member. As a result, the main body 601 of the tensioning member 60 is pressed and moved by the eccentric portion 81 of the eccentric cam 80, and rotates a predetermined amount in the clockwise direction around the rotating shaft 603a.

[0185] Therefore, if Figure 19 As shown, the plurality of locking claws 602, 602, etc. provided at the upper end of the tensioning member 60 move toward the charging area along the longitudinal direction of the charging device 12 as the tensioning member 60 rotates, thereby releasing or reducing the tension applied to the grid electrode 122. As a result, the grid electrode 122 returns to its original flat shape due to its inherent elastic restoring force.

[0186] Then, if Figure 13 As shown, the cleaning device 70 rotates the drive shaft 209 to gradually move the driving portion 716 of the cleaning device 70 engaged with the drive shaft 209 along the long side direction of the charging device 12 from the insulating block 126 side at the rear end toward the insulating block 125 side at the front end.

[0187] like Figure 17 As shown in (a) and (b), if the cleaning device 70 is separated from the insulating block 126 at the rear end, the pressing and moving action of the working arm 126e of the insulating block 126 at the rear end pressing and moving the working parts 736a, 737a of the swing arm 73 of the cleaning device 70 is released, and the swing arm 73 is rotated counterclockwise by the force of the coil spring 740, and the cleaning pads 738, 739 abut against the cleaning pads 726, 727 of the lower main body 72 in a state where the two discharge wires 121, 121 are pressed from the top.

[0188] By doing so, the two discharge wires 121, 121 of the charging device 12 are clamped by the cleaning pads 738, 739 and the cleaning pads 726, 727 arranged above and below the cleaning device 70, and as the cleaning device 70 moves along the long side direction L of the charging device 12, the total length of the two discharge wires 121, 121 is cleaned.

[0189] And, as Figure 20As shown, the cleaning device 70 cleans the grid electrode 122 by means of a cleaning pad 728 provided on the lower body 72 thereof. The lower surfaces of the two ends of the grid electrode 122 in the width direction (the surfaces on the photosensitive drum 11 side) are supported by the support plate portion of the lower body 72. At this time, the grid electrode 122 is deformed into a flat shape, so that the cleaning pad 728 can be brought into contact with the entire surface of the grid electrode 122 for cleaning, compared to the case where the cleaning is performed while the grid electrode 122 is kept in a curved shape. This improves the cleaning performance of the grid electrode 122 and allows for good cleaning. Therefore, it is possible to prevent or even suppress a reduction in the cleaning performance of the grid electrode 122, which in turn reduces the performance of the grid electrode 122 and causes uneven charging due to the charging device 12.

[0190] When the cleaning device 70 reaches the insulating block 125 at the front end of the charging device 12 and completes cleaning the discharge wires 121 and grid electrode 122, the drive shaft 209 is rotated in the opposite direction to return to the standby position, thereby completing the series of cleaning operations. Furthermore, the cleaning device 70 can effectively clean the discharge wires 121 and grid electrode 122 by repeatedly reciprocating along the longitudinal direction L of the charging device 12.

[0191] In addition, if Figure 21 As shown, the cleaning device 70 can be configured as follows: by designing the surface shape of the cleaning pad 728 provided on the lower body 72 or the shapes of the support plates 729 and 730 supporting the grid electrode 122 at both ends in the width direction, the grid electrode 122 is not only flat but also slightly curved downward into a convex shape. In this manner, the tension on the grid electrode 122 is released or reduced, making it easy and reliable to curve the grid electrode 122 slightly downward into a convex shape.

[0192] When the cleaning device 70 moves to the standby position, the cleaning pads 738 , 739 and the cleaning pads 726 , 727 are separated from the two discharge wires 121 , 121 , and the cleaning pad 728 is separated from the grid electrode 122 .

[0193] Implementation Method 2

[0194] Figure 22 1 is a diagram showing the configuration of a charging device according to Embodiment 2 of the present invention. The charging device according to Embodiment 2 is configured such that a deforming member changes the shape of a holding portion holding a control electrode from a curved or bent shape to a flat shape.

[0195] Furthermore, in this embodiment 2, it is constructed as follows: the deformable member has a retaining part that retains one end of the control electrode along a direction intersecting with the rotation direction of the charged body, and the retaining part has: a curved portion that bends or folds the control electrode along the surface shape of the charged body when charged; and a flat portion that deforms the shape of the control electrode into a flat shape different from that when charged when cleaned.

[0196] That is, Figure 22 As shown, the charging device 12 involved in this embodiment 2 is constructed as follows: the retaining portion provided on the insulating block 125 at the front end of one end portion along the long side direction L of the grid electrode 122 is a retaining component 130 which is an example of a deformable member but is a component different from the insulating block 125.

[0197] like Figure 23 As shown, the holding member 130 is mounted on the insulating block 125 so as to be rotatable about a rotation axis 131 disposed along the width direction W of the grid electrode 122. The holding member 130 is rotationally driven by a drive motor or solenoid provided in the charging device 12 or by a pinion, etc., which is disposed along the longitudinal direction of the charging device 12 and can be meshed with a rack movable along the longitudinal direction via an operating portion provided on the mounting member 127.

[0198] Holding member 130 includes a curved portion 132 corresponding to the curved shape of grid electrode 122 provided on its upper end surface, and a flat portion 133 provided on a surface adjacent to curved portion 132. Flat portion 133 of holding member 130 is configured to protrude from the surface of insulating block 125 to the same extent as or less than curved portion 132. When holding member 130 rotates about rotation axis 131 and flat portion 133 contacts grid electrode 122, grid electrode 122 is held in its deformed, flat shape.

[0199] The holding member 130 may be provided only on the front end insulating block 125 , or may be provided on both the front and rear end insulating blocks 125 and 126 .

[0200] like Figure 24 As shown, in the charging device 12 involved in this embodiment 2, during cleaning, the grid electrode 122 can be deformed into a flat plate shape similar to the flat plate 133 of the holding component 130 by rotating the flat surface 133 of the holding component 130 in a manner that holds the grid electrode 122.

[0201] Therefore, the cleaning device 70 that cleans the charging device 12 can clean the grid electrode 122 uniformly and satisfactorily by cleaning the grid electrode 122 that has been deformed into a flat plate shape.

[0202] The other structures and functions are the same as those in the first embodiment, so their description is omitted.

[0203] Implementation 3

[0204] Figure 25 The diagram shows a configuration of a charging device according to Embodiment 3 of the present invention. The charging device according to Embodiment 3 is configured such that during charging, the control electrode is pressed by a restricting member provided on the charged object side and has a curved shape along the surface shape of the charged object.

[0205] Furthermore, the charging device according to the third embodiment is configured such that the deforming member deforms the shape of the control electrode into a shape different from that during charging by changing the position of the charging device in a direction away from the charged body.

[0206] That is, Figure 25 As shown, the charging device 12 according to the third embodiment includes a retracting mechanism 300 as an example of a deforming member. The charging device 12 is configured to be movable between a charging position close to the photosensitive drum 11 and a cleaning position away from the photosensitive drum 11 by the retracting mechanism 300 including a guide rail 301 .

[0207] Unlike the previous embodiment, the charging device 12 has the grid electrode 122 stretched flat. However, the charging device 12 according to this third embodiment is not limited to the case where the grid electrode 122 is stretched flat. As in the first embodiment, a deforming member that deforms the grid electrode 122 from a curved shape to a flat shape may also be included. In this case, the charging device 12 is configured to perform the next operation after the grid electrode 122 is deformed from a curved shape to a flat shape.

[0208] When charging, the charging device 12 is located at a charging position close to the photosensitive drum 11 by the retraction mechanism. Figure 25 As shown in FIG. 1 ( b ), the grid electrode 122 of the charging device 12 is deformed into a curved shape similar to the surface shape of the photosensitive drum 11 by being pressed against the curved portions 207 and 208 provided in the image forming unit 200 .

[0209] In addition, Figure 25 In (b), in order to show the grid electrode 122 deformed into a curved shape, the width of the grid electrode 122 in the thickness direction is shown in a wider diagram.

[0210] On the other hand, during cleaning, the charging device 12 is moved by the retraction mechanism to a cleaning position separated from the photosensitive drum 11. When moving to the cleaning position, the grid electrode 122 of the charging device 12 is separated from the curved portions 207 and 208 of the image forming unit 200, thereby returning to its original flat shape from the curved shape along the surface shape of the photosensitive drum 11.

[0211] Then, the charging device 12 cleans the discharge wire and the grid electrode 122 by the cleaning device 70 while the grid electrode 122 is deformed into a planar shape.

[0212] In addition, in the charging device 12 involved in this embodiment 3, the following situation is described: the free shape of the grid electrode 122 is set to a planar shape, and when charged, the two end portions of the grid electrode 122 along the long side direction L are pressed by the curved portions 207 and 208 of the image forming unit 200 to form a curved shape.

[0213] However, the charging device 12 involved in this embodiment 3 is not limited to this, and can also be constructed as follows: the grid electrode 122 is configured to be bent toward the charging device 12, and during cleaning, for example, by pressing a pressing component whose front end is not shown and is formed into a flat plate on the side of the image forming unit 200, the grid electrode 122 is deformed into a flat shape.

[0214] Furthermore, the charging device 12 may be configured to be separated from the photosensitive drum 11 at any time before or after the grid electrode 122 is deformed.

[0215] The other structures and functions are the same as those in the first embodiment, so their description is omitted.

[0216] Implementation 4

[0217] Figure 26 1 is a diagram showing the configuration of a charging device according to Embodiment 4 of the present invention. The charging device according to Embodiment 4 is configured such that the control electrode has a bent shape instead of a curved shape following the surface shape of the charged body.

[0218] That is, Figure 26 As shown, the charging device 12 according to the fourth embodiment is arranged such that the grid electrode 122 is bent into a substantially V-shape or the like along the surface shape of the photosensitive drum 11 .

[0219] The grid electrode 122 may be a flat plate-shaped grid electrode bent into a substantially V-shape, etc. However, by combining a plurality of flat plate-shaped grid electrodes 122, the grid electrode 122 is arranged in a shape bent along the surface shape of the photosensitive drum 11. In addition, the grid electrode 122 is not limited to the shape bent into a substantially V-shape. Figure 27 As shown, when the charging device 12 has three discharge wires 121, for example, the grid electrode 122 may be arranged in a multi-faceted shape.

[0220] like Figure 28As shown, the holding portions 125a and 126a of the insulating blocks 125 and 126 holding the grid electrode 122 are formed to be bent into a shape such as an inverted V shape similar to the shape of the grid electrode 122, rather than being bent into a curved shape.

[0221] When the grid electrode 122 is composed of two flat-plate-shaped grid electrodes 122, as shown in FIG. Figure 28 As shown, the lower body 72 holding the grid electrodes 122 of the cleaning device 70 is configured to hold two grid electrodes 122 in a flat plate shape.

[0222] That is, during cleaning, when the cleaning device 70 moves from the connecting portion 122c located at one end of the grid electrode 122 to the connecting portion 122b, the two ends of the two grid electrodes 122 arranged in a V shape along their width direction W are held by the flat bracket part 150 of the cleaning device 70 and deformed into a flat shape.

[0223] Figure 29 It is a structural diagram showing a modified example of the charging device according to the fourth embodiment.

[0224] like Figure 29 As shown, in a modified example of the charging device 12 involved in this embodiment 4, it is constructed as follows: the tensioning parts that tension the two grid electrodes 122 and 122 at both ends along the long side direction can be opened and closed in a hinge shape via a central axis arranged between the two grid electrodes 122.

[0225] Then, in the charging device 12, as shown in FIG. Figure 29 As shown, during cleaning, the tensioning member is rotated so as to tension the two grid electrodes 122 into a flat plate shape, whereby the two grid electrodes 122 can be deformed into a flat plate shape and cleaned by the cleaning device 70 .

[0226] Figure 30 This is a structural diagram showing a further modified example of the charging device according to the fourth embodiment.

[0227] In a modified example of the charging device 12, as shown in FIG. Figure 30 As shown, similarly to the second embodiment, the tension member 60 for tensioning the two grid electrodes 122 in a V-shape includes a V-shaped curved surface portion 132 and a flat surface portion 133 .

[0228] Furthermore, in this modified example of the charging device 12 , during cleaning, the flat surface portion 133 of the tension member 60 is rotated so as to contact the two grid electrodes 122 , thereby deforming the two grid electrodes 122 into a flat plate shape.

[0229] The other structures and functions are the same as those in the first embodiment, so their description is omitted.

[0230] Furthermore, in the above-described embodiment, a full-color image forming apparatus has been described, but it is of course also applicable to a monochrome image forming apparatus.

[0231] Furthermore, in the above embodiment, the case where the number of discharge wires 121 is two has been described. However, the number of discharge wires 121 is not limited to two, and may be one, or three or more.

[0232] (Note) (1)

[0234] A charging device comprising:

[0235] discharge electrode;

[0236] a control electrode disposed between the discharge electrode and a charged object charged by the discharge electrode, and bent or folded along a surface shape of the charged object;

[0237] a cleaning member for cleaning at least the control electrode among the discharge electrode and the control electrode; and

[0238] The deforming member deforms the control electrode into different shapes during cleaning by the cleaning member and during charging. (2)

[0240] The charging device according to (1), wherein the control electrode is stretched with tension applied in a direction intersecting the rotation direction of the charged body, and is held by a holding member in a shape bent or folded along the surface shape of the charged body. (3)

[0242] The charging device according to (2), wherein during cleaning, the deforming member reduces tension on the control electrode to deform the control electrode into a shape different from that during charging. (4)

[0244] The charging device according to (1), wherein at least one end portion of the control electrode in a direction intersecting the rotational direction of the charged body is urged outward relative to the charged region of the charged body by a tension member. (5)

[0246] According to the charging device described in (4), the deforming member deforms the control electrode into a shape different from that when charged by changing the position of the tensioning part on the other end of the control electrode toward the inside relative to the charged area of ​​the charged body along a direction intersecting with the rotation direction of the charged body. (6)

[0248] The charging device according to (1), wherein the deforming member changes the shape of the holding portion holding the control electrode from a bent or folded shape to a planar shape. (7)

[0250] According to the charging device described in (6), the deformable member has a holding part that holds one end of the control electrode along a direction intersecting with the rotation direction of the charged body, and the holding part has: a curved portion that bends or folds the control electrode along the surface shape of the charged body when charged; and a flat portion that deforms the shape of the control electrode into a flat shape different from that when charged when cleaned. (8)

[0252] The charging device according to (1), wherein during charging, the control electrode is pressed by a restriction member provided on the side of the charged object and thus has a shape curved along the surface shape of the charged object. (9)

[0254] The charging device according to (8), wherein the deforming member deforms the shape of the control electrode into a shape different from that during charging by changing the position of the charging device in a direction away from the charged body. (10)

[0256] The charging device according to (1), wherein the deforming member deforms the shape of the control electrode into a shape different from that during charging, and changes the position of the charging device in a direction away from the charged object. (11)

[0258] The charging device according to (1), wherein the deforming member deforms the shape of the control electrode into a shape different from that during charging by pressing both end portions of the control electrode in a direction intersecting the rotation direction of the charged body. (12)

[0260] According to the charging device described in (11), the deformable member has a pressing part that presses the two end portions of the control electrode along a direction intersecting the rotation direction of the charged body, and the pressing part has a pressing portion that deforms the control electrode into a planar shape. (13)

[0262] The charging device according to (1), wherein the cleaning member cleans both the discharge electrode and the control electrode. (14)

[0264] According to the charging device described in (13), the cleaning member has a first cleaning part that contacts the discharge electrode and a second cleaning part that contacts both front and back surfaces of the control electrode deformed into a shape different from that during charging. (15)

[0266] An image forming unit includes the charging device described in any one of (1) to (14), wherein the image forming unit is attachable to and detachable from an image forming apparatus. (16)

[0268] An image forming apparatus comprising:

[0269] Image holding member;

[0270] a charging member for charging the surface of the image holding member; and

[0271] an electrostatic latent image forming member for forming an electrostatic latent image on the surface of the image holding member charged by the charging member,

[0272] The image forming apparatus uses the charging device described in any one of (1) to (14) as the charging member.

[0273] According to the charging device according to (1), compared with cleaning the control electrode while maintaining the same shape as during charging, contact between the control electrode and the surface of the charged object can be avoided, and the cleaning performance of the control electrode can be improved.

[0274] According to the charging device according to (2), a planar control electrode can be adopted compared to a case where the control electrode is formed into a curved or bent shape along the surface shape of the charged body without using a holding member.

[0275] According to the charging device involved in (3), compared with the case where the deforming member applies external force to the control electrode during cleaning to deform it into a shape different from that during charging, the control electrode can be easily deformed into a shape different from that during charging simply by reducing the tension.

[0276] According to the charging device of (4), compared with a case where no tension member is used for the control electrode, the structure for applying force to the control electrode outward relative to the charged region of the charged body can be simplified.

[0277] According to the charging device according to (5), the structure of the tension member becomes simpler compared to a case where the deformation member causes the tension member to change the positions of both end portions of the control electrode.

[0278] According to the charging device according to (6), the structure of the deforming member becomes simpler compared to a case where the deforming member changes its shape except for the holding portion that holds the control electrode.

[0279] According to the charging device according to (7), the shape of the control electrode can be deformed by a single holding member, compared to a case where the deforming member includes a curved portion and a flat portion on different holding members.

[0280] According to the charging device according to (8), the control electrode can be bent or folded more easily than when the control electrode is bent or folded by restricting members provided on both the charging device and the charged body during charging.

[0281] According to the charging device according to (9), the shape of the control electrode can be easily changed by simply changing the position of the charging member, compared to the case where the deforming member changes the tension of the control electrode.

[0282] According to the charging device according to (10), it is possible to suppress the contact between the cleaning member and the surface of the charged object and clean both the front and back surfaces of the control electrode along the surface shape of the charged object.

[0283] According to the charging device involved in (11), the shape of the control electrode can be reliably deformed compared to the case where the deforming member changes the tension of the control electrode.

[0284] According to the charging device involved in (12), the control electrode can be reliably deformed into a planar shape compared to a case where the deformable member does not have parts for pressing the two end portions of the control electrode along the long side direction, that is, a pressing part having a pressing portion for deforming the control electrode into a planar shape.

[0285] According to the charging device involved in (13), the structure of the cleaning member can be simplified compared to the case where the cleaning member cleans only the control electrode.

[0286] According to the charging device involved in (14), compared with the case where the cleaning member does not have a first cleaning part that contacts the discharge electrode and a second cleaning part that contacts the front and back surfaces of the control electrode that is deformed into a shape different from that during charging, it is possible to clean both the discharge electrode and the control electrode.

[0287] According to the image forming unit involved in (15), compared with the case where the charging device described in any one of (1) to (14) is not provided, it is possible to suppress the contact between the cleaning member and the surface of the charged body and clean the front and back surfaces of the control electrode that is bent along the surface shape of the charged body.

[0288] According to the image forming device involved in (16), compared with the case where the charging device described in any one of (1) to (14) is not used as the charging component, it is possible to suppress the contact between the cleaning component and the surface of the charged body and clean the front and back surfaces of the control electrode that is bent along the surface shape of the charged body.

[0289] The above-described embodiments of the present invention are provided for the purpose of illustration and explanation. In addition, the embodiments of the present invention do not fully and exhaustively include the present invention, and do not limit the present invention to the disclosed embodiments. It is obvious that various modifications and variations are self-evident to those skilled in the art to which the present invention belongs. The present embodiment is selected and described in order to most easily explain the principles of the present invention and its application. Thus, other technical personnel in this field can understand the present invention through various modifications optimized for specific uses of the assumed various embodiments. The scope of the present invention is defined by the above claims and their equivalents.

Claims

1. A charging device comprising: discharge electrode; a control electrode disposed between the discharge electrode and a charged object charged by the discharge electrode, and bent or folded along a surface shape of the charged object; a cleaning member for cleaning at least the control electrode among the discharge electrode and the control electrode; and The deforming member deforms the control electrode into different shapes during cleaning by the cleaning member and during charging.

2. The charging device according to claim 1, wherein The control electrode is stretched with tension applied in a direction intersecting the rotational direction of the charged body, and is held by a holding member in a shape that is curved or bent along the surface shape of the charged body.

3. The charging device according to claim 2, wherein: During cleaning, the deforming member reduces tension on the control electrode, thereby deforming the control electrode into a shape different from that during charging.

4. The charging device according to claim 1, wherein At least one end portion of the control electrode in a direction intersecting the rotational direction of the charged body is urged outward relative to the charged region of the charged body by a tension member.

5. The charging device according to claim 4, wherein: The deforming member deforms the control electrode into a shape different from that when charged by changing the position at which the tensioning part tensions the other end of the control electrode inward relative to the charged area of ​​the charged body in a direction intersecting the rotation direction of the charged body. The charging device according to claim 1 , wherein: The deforming member changes the shape of the holding portion holding the control electrode from a curved or bent shape to a flat shape.

7. The charging device according to claim 6, wherein: The deformable member has a retaining part that retains one end of the control electrode along a direction intersecting with the rotation direction of the charged body, and the retaining part has: a curved portion that bends or folds the control electrode along the surface shape of the charged body when charged; and a flat portion that deforms the shape of the control electrode into a flat shape different from that when charged when cleaned.

8. The charging device according to claim 1, wherein: During charging, the control electrode is pressed by a restriction member provided on the side of the charged object, thereby forming a shape curved along the surface shape of the charged object.

9. The charging device according to claim 8, wherein: The deforming member deforms the shape of the control electrode into a shape different from that during charging by changing the position of the charging device in a direction away from the charged body.

10. The charging device according to claim 1, wherein The deforming member deforms the shape of the control electrode into a shape different from that during charging, and changes the position of the charging device in a direction away from the charged object.

11. The charging device according to claim 1, wherein The deforming member deforms the control electrode into a shape different from that during charging by pressing both end portions of the control electrode in a direction intersecting the rotation direction of the charged body.

12. The charging device according to claim 11, wherein The deforming member includes pressing members that press both end portions of the control electrode in a direction intersecting with the rotation direction of the charged body, and the pressing members include pressing portions that deform the control electrode into a planar shape.

13. The charging device according to claim 1, wherein The cleaning member cleans both the discharge electrode and the control electrode.

14. The charging device according to claim 13, wherein: The cleaning member includes a first cleaning component that contacts the discharge electrode and a second cleaning component that is deformed into a shape different from that when charged and contacts both front and back surfaces of the control electrode.

15. An image forming unit comprising the charging device according to any one of claims 1 to 14, The image forming unit is attachable to and detachable from the image forming apparatus.

16. An image forming apparatus comprising: Image holding member; a charging member for charging the surface of the image holding member; and an electrostatic latent image forming member for forming an electrostatic latent image on the surface of the image holding member charged by the charging member, The image forming apparatus uses the charging device according to any one of claims 1 to 14 as the charging member.

Images