JP2011059618A - Charger - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a charger in which an opposite electrode can be satisfactorily cleaned by changing a cleaning condition. <P>SOLUTION: The charger 54 includes: a discharge wire 110 extended along a predetermined direction; the opposite electrode 120 extended along the extension direction of the discharge wire 110 and faced to the discharge wire 110; a frame (upper side frame 100) configured to support the discharge wire 110 and the opposite electrode 120; and a cleaning member 200 configured to move in the extension direction while slidably contacting with the opposite electrode 120 to clean the opposite electrode 120. Then, the cleaning member 200 includes a flexibly deformable sheet-like member 220 which contacts with the opposite electrode 120, and the sheet-like member 220 has different roughness at a front surface and a reverse surface, and when switching the moving direction of the cleaning member 200, a portion of the sheet-like member 220, which contacts with the opposite electrode 120, is turned upside down between the front surface and the reverse surface. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

  The present invention relates to a charger provided with a cleaning member for cleaning a counter electrode facing a discharge wire.

  Conventionally, as a charger, a discharge wire extending in the axial direction of the photosensitive drum, a grid electrode (counter electrode) disposed between the discharge wire and the photosensitive drum, and both the discharge wire and the grid electrode are slidably contacted and cleaned. A thing provided with a cleaning member is known (refer to patent documents 1 and 2). In such a technique, a sponge-like part is usually used for the portion of the cleaning member that is in sliding contact with the grid electrode, and this sponge-like member is always in sliding contact with the grid electrode.

JP-A-4-369663 Japanese Patent Laid-Open No. 7-301978

  However, the above-described technique has a problem in that since the sponge-like material is always slidably contacted with the grid electrode, the cleaning conditions do not change and various foreign matters attached to the grid electrode cannot be cleaned well. Specifically, for example, if the toner is fixed on the grid electrode, there is a problem that it is difficult to sufficiently remove the fixed toner with a soft sponge.

  Accordingly, an object of the present invention is to provide a charger that can clean the counter electrode satisfactorily by changing the cleaning conditions.

  The present invention that solves the above-described problems includes a discharge wire that extends along a predetermined direction, a counter electrode that extends along a direction in which the discharge wire extends and faces the discharge wire, and the discharge wire and the counter And a frame that supports the electrode, and includes a cleaning member that cleans the counter electrode by moving in the extending direction while being in sliding contact with the counter electrode, and a moving direction of the cleaning member Is selectively switchable between a first direction along the extending direction and a second direction opposite to the first direction, and the cleaning member is a deformable sheet that contacts the counter electrode. The sheet-like member has a different surface roughness, and is configured such that a portion that contacts the counter electrode is reversed when the direction of movement of the cleaning member is switched. And

  According to the present invention, since the sheet-like members having different front and back roughnesses are reversed when the direction of movement of the cleaning member is switched, the cleaning conditions can be changed between the forward path and the return path of the cleaning member. Therefore, for example, toner adhered on a rough surface can be scraped off on the forward path, and toner scraped off on a fine surface can be wiped off on the return path, and the counter electrode can be cleaned well.

  According to the present invention, since the cleaning conditions can be changed by reversing the sheet-like members having different front and back surface roughnesses, the counter electrode can be cleaned well.

1 is a cross-sectional view illustrating an overall configuration of a color printer. It is an expanded sectional view which shows the structure of a process cartridge. It is a perspective view which shows the upper side frame with which the cleaning member was mounted | worn. It is a perspective view which shows the cleaning member. It is a disassembled perspective view which decomposes | disassembles and shows a cleaning member. They are the front view (a) which looked at the supporting member from the front end side of the 1st projection, and the top view (b) which shows a sheet-like member. Sectional view (a) showing a state in which the cleaning member is moved in one direction, sectional view (b) showing a state in which the sheet-like member has passed over the engaging portion, and the sheet-like member inverted by the engaging portion It is sectional drawing (c) which shows the state made. It is a disassembled perspective view which shows the state which attaches the cleaning member to an upper frame. A bottom view (a) of the upper frame with the discharge wire, the counter electrode and the cleaning member removed from the lower side, and an upper frame with the discharge wire, the counter electrode and the cleaning member attached are shown in FIG. 9 (a). It is XX sectional drawing (b) cut | disconnected by the XX line. It is sectional drawing which shows the form which employ | adopted the metal file as an abrasive member.

  Next, an embodiment of the present invention will be described in detail with reference to the drawings as appropriate. In the following description, first, the overall configuration of the color printer will be briefly described, and then the characteristic part of the present invention will be described.

<Overall configuration of color printer>
As shown in FIG. 1, the color printer 1 includes a paper feeding unit 20 that supplies paper P, an image forming unit 30 that forms an image on the fed paper P, and an image formed in a main body housing 10. And a paper discharge unit 90 for discharging the paper P.

  An openable and closable upper cover 12 is provided on the upper portion of the main body casing 10. The upper surface of the upper cover 12 serves as a paper discharge tray 13 that accumulates the paper P discharged from the main body housing 10, and a plurality of holding members 14 that hold a plurality of LED units 40 described later are provided on the lower surface. ing.

  The paper feeding unit 20 is provided in the lower part of the main body housing 10, and is a paper feeding tray 21 that is detachably attached to the main body housing 10, and a paper that conveys the paper P from the paper feeding tray 21 to the image forming unit 30. A supply mechanism 22 is mainly provided.

  The image forming unit 30 mainly includes four LED units 40, four process cartridges 50, a transfer unit 70, and a fixing unit 80.

  The process cartridge 50 is arranged side by side in the front-rear direction between the upper cover 12 and the paper feed unit 20, and as shown in FIG. 2, the photosensitive cartridge 51 and a developing cartridge that can be attached to and detached from the photosensitive cartridge 51. 61. Each process cartridge 50 has the same configuration except that the color of the toner stored in the toner storage chamber 66 of the developing cartridge 61 is different.

  The photoconductor cartridge 51 mainly includes a drum case 52 and a photoconductive drum 53 and a charger 54 as an example of a photoconductor accommodated in the drum case 52.

  The developing cartridge 61 includes a developing case 62, a developing roller 63 accommodated in the developing case 62, a supply roller 64 and a blade assembly 65, and a toner accommodating chamber 66 formed in the developing case 62. .

  As shown in FIG. 1, the transfer unit 70 is provided between the paper feeding unit 20 and each process cartridge 50, and mainly includes a drive roller 71, a driven roller 72, a conveyance belt 73, and a transfer roller 74.

  The fixing unit 80 is disposed on the rear side of each process cartridge 50 and the transfer unit 70, and includes a heating roller 81 and a pressure roller 82 that is disposed to face the heating roller 81 and presses the heating roller 81.

  In the image forming unit 30 configured as described above, first, as shown in FIG. 2, the surface of the photosensitive drum 53 is uniformly charged by the charger 54, and then is irradiated with light emitted from each LED unit 40. Exposed. As a result, the potential of the exposed portion is lowered, and an electrostatic latent image based on the image data is formed (carried) on the surface of the photosensitive drum 53.

  Further, the toner in the toner storage chamber 66 is supplied to the developing roller 63 by the rotation of the supply roller 64, and enters the space between the developing roller 63 and the blade assembly 65 by the rotation of the developing roller 63 and is thin with a certain thickness. It is carried on the developing roller 63 as a layer.

  The toner carried on the developing roller 63 is supplied to the electrostatic latent image formed on the photosensitive drum 53 when the developing roller 63 comes into contact with the photosensitive drum 53. As a result, the toner is selectively carried on the photosensitive drum 53 to visualize the electrostatic latent image, and a toner image is formed by reversal development.

  As shown in FIG. 1, the sheet P supplied onto the conveyor belt 73 passes between the photosensitive drums 53 and the transfer rollers 74 disposed inside the conveyor belt 73, so that each photosensitive drum The toner image formed on 53 is transferred onto the paper P. When the paper P passes between the heating roller 81 and the pressure roller 82, the toner image transferred onto the paper P is thermally fixed.

  The paper discharge unit 90 includes a paper discharge side conveyance path 91 that extends upward from the exit of the fixing unit 80 and is reversed to the front side, and a plurality of pairs of conveyance rollers 92 that convey the paper P. Yes. The paper P on which the toner image has been transferred and heat-fixed is transported through a paper discharge-side transport path 91 by a transport roller 92, discharged outside the main body housing 10, and accumulated in the paper discharge tray 13.

<Charger structure>
Next, the structure of the charger 54 will be described in detail.
As shown in FIG. 2, the charger 54 includes a resin (insulating) upper frame 100 as an example of a frame constituting the upper portion of the drum case 52, and a discharge wire 110 supported by the upper frame 100. And a counter electrode 120 and a cleaning member 200 shown in FIG.

  The discharge wire 110 is a wire that extends along the axial direction (predetermined direction) of the photosensitive drum 53, and is disposed in a long groove 101 (see FIG. 3) formed in the upper frame 100, and both ends thereof are arranged on the upper frame. 100.

  The counter electrode 120 is a plate-like electrode that extends along the axial direction of the photosensitive drum 53 and is bent in a U-shape in cross section so as to face the discharge wire 110, and mainly includes the grid electrode 121 and a pair of And a shield electrode 122.

  The grid electrode 121 is an electrode disposed between the discharge wire 110 and the photosensitive drum 53, and is formed into a plurality of wires by forming a plurality of slits at the bottom of the U-shaped counter electrode 120. .

  Each shield electrode 122 is disposed so as to face (position) so as to sandwich the discharge wire 110 in the moving direction of the surface of the photosensitive drum 53. Here, “the moving direction of the surface of the photosensitive drum 53” refers to the moving direction of the portion of the photosensitive drum 53 that faces the grid electrode 121 (in FIG. 2, diagonally upward).

  As shown in FIG. 3, the cleaning member 200 is movably mounted in the long groove 101 of the upper frame 100, and the moving direction is defined as the first direction and the first direction along the extending direction of the discharge wire 110. It is possible to selectively switch to the opposite second direction. The cleaning member 200 cleans the discharge wire 110 and the counter electrode 120 by moving while slidingly contacting the discharge wire 110 and the counter electrode 120 (see FIG. 2). Specifically, as illustrated in FIG. 4, the cleaning member 200 includes a support member 210, a sheet-like member 220, and a plate-like sponge 230 as an example of a sliding contact member.

  As shown in FIG. 5, the support member 210 mainly includes an operation portion 211 formed in a substantially rectangular flat plate shape and two arm portions 212 that can be bent and deformed downward from the lower surface of the operation portion 211. Yes. Each arm portion 212 is formed with a first protrusion 213 and a second protrusion 214 for supporting the sheet-like member 220 and the plate-like sponge 230.

  Each first protrusion 213 is formed in a substantially triangular prism shape, and supports the sheet-like member 220 in a state of penetrating through an engagement hole 227 formed in the sheet-like member 220. More specifically, each first protrusion 213 supports one and the other of the sheet-like member 220 separated by the slit 226. In addition, the first protrusion 213 contributes to suppressing both ends of the plate-like sponge 230 bent in a substantially U shape from spreading in a direction away from each other.

  Each of the second protrusions 214 is formed in a quadrangular prism shape, and supports the bent portion of the substantially U-shaped plate-like sponge 230 so as to sandwich it.

  As shown in FIG. 5, the sheet-like member 220 is a member that can bend and deform in contact with the counter electrode 120, and is configured so that the front and back surfaces have different roughnesses. The sheet-like member 220 is in contact with the counter electrode 120 due to friction with the counter electrode 120 and engagement with an engagement portion 108 (see FIG. 7) described later when switching the moving direction of the cleaning member 200. Is configured to be reversed.

  Specifically, the sheet-like member 220 is made of a deformable PET film 240, a polishing member 250 as an example of the first member, and a second member (wiping member) made of a different material from the first member. An example felt member 260 is laminated. The sheet-like member 220 is supported by the support member 210 so as to be substantially perpendicular to the grid electrode 121 and the shield electrode 122.

  A polishing member 250 is fixed to the surface of the film 240, and a felt member 260 is fixed to the back surface thereof. By using such a film 240 that can be bent and deformed, it is possible to press the polishing member 250 and the felt member 260 fixed to both surfaces against the counter electrode 120 with a desired pressure.

  In this embodiment, the polishing member 250 and the felt member 260 are brought into surface contact with the counter electrode 120 (see FIG. 7). However, the present invention is not limited to this, and the corners of the polishing member 250 and the felt member 260 are used. May be configured to contact the counter electrode 120.

  The polishing member 250 is a member constituting the surface of the sheet-like member 220, and is a polishing-type material having a polishing surface (such as a sheet-like metal file or a paper file). ). Thereby, the toner fixed to the grid electrode 121 can be scraped by the polishing member 250.

  The felt member 260 is a member constituting the back surface of the sheet-like member 220, and is made of a soft porous material having a surface roughness finer than that of the polishing member 250 and soft. As a result, it is possible to satisfactorily wipe off the foreign matters, the deposits on the electrodes, and the like generated by scraping with the polishing member 250 with the felt member 260.

  The film 240, the polishing member 250, and the felt member 260 have the same shape. That is, a sheet-like member 220 having a shape as shown in the figure can be easily manufactured by punching out a sheet-like member obtained by bonding the three members with a predetermined mold.

  Thus, the sheet-like member 220 composed of three layers has a distal end portion 221 as a first end that contacts the grid electrode 121 (see FIG. 2), and a proximal end located on the opposite side of the distal end portion 221. And a pair of side end portions 223 as a second end portion configured to intersect with the tip end portion 221 on both sides of the tip end portion 221 and in contact with the pair of shield electrodes 122 (see FIG. 2). ing.

  A notch 224 is formed between the front end portion 221 and the side end portions 223 of the sheet-like member 220. As a result, the front end portion 221 and both side end portions 223 of the sheet-like member 220 are not affected by each other's bending, so that the front end portion 221 and both side end portions 223 of the sheet-like member 220 can be accurately connected to the grid electrode 121 and Each shield electrode 122 can be contacted.

  Further, the sheet-like member 220 is formed with a hole 225 for allowing the discharge wire 110 (see FIG. 2) to pass therethrough, and a slit 226 extending from the hole 225 to the tip 221. The hole 225 is formed in a shape that is not line symmetric with respect to the slit 226. Thereby, for example, it is possible to prevent erroneous assembly such that the front and back of the sheet-like member 220 are mistaken by visual observation, and to prevent a good assembly by the burrs formed at the edges of the holes 225 and the like.

  In order to prevent erroneous assembly, instead of devising the shape of the hole 225, the left first protrusion 213 and the right first protrusion 213 are formed to have different shapes and matched to these shapes. You may form so that the shape of each engagement hole 227 mentioned later may differ. Separately, a structure for preventing misassembly (for example, in the support member 210, a protrusion is provided only on one of the left and right sides of the slit 226, and a hole into which the protrusion enters is formed in the sheet-like member 220). It may be provided.

  Further, the sheet-like member 220 is formed with an engagement hole 227 formed symmetrically with respect to the slit 226 so as to sandwich the slit 226. As shown in FIGS. 6A and 6B, the engagement hole 227 includes three corners 227A, 227B, which engage with the three corners 213A, 213B, 213C of the first protrusion 213 of the support member 210. 227C.

  The three corners 227A, 227B, 227C are formed at positions rotated by a slight angle from the positions of the three corners 213A, 213B, 213C. Specifically, the direction of this rotation is the direction in which the slit 226 opens (moves in an arc shape so that one and the other separated by the slit 226 are separated from each other around the base end portion 222 of the sheet-like member 220). (Direction) is the opposite direction.

  More specifically, the three corners 227A, 227B, 227C on the left side of the figure are formed at positions rotated counterclockwise in the figure from the positions of the three corner parts 213A, 213B, 213C on the left side of the figure. Also, the three corners 227A, 227B, 227C on the right side of the figure are formed at positions rotated clockwise from the position of the three corner parts 213A, 213B, 213C on the right side of the figure.

  Thereby, when each engagement hole 227 of the sheet-like member 220 is attached to the first protrusion 213 of the support member 210, each corner 227A, 227B, 227C moves to the position of each corner 213A, 213B, 213C. As a result, the slit 226 is slightly opened (see FIG. 4). That is, the slit 226 is configured to open depending on the difference in the shape of the attachment portion (each first protrusion 213 and each engagement hole 227) between the arm portion 212 and the sheet-like member 220.

  As shown in FIG. 5, the plate-like sponge 230 is a member that is slidably contacted with the discharge wire 110 (see FIG. 2) in the extending direction, and each of the support members 210 is bent in a substantially U shape. It is clamped by the second protrusion 214. The sheet-like member 220 is sandwiched between the plate-like sponge 230 and the support member 210 by being sandwiched between the second protrusions 214 in this way.

  Then, as shown in FIG. 7A, on both sides of the counter electrode 120, specifically, on the bottom surface 106 and both side surfaces 107 (only one side is shown) on both sides of the long groove 101 formed in the upper frame 100, An engaging portion 108 protruding inward is provided. Thus, as shown in FIGS. 7B and 7C, when the moving direction of the cleaning member 200 is switched after the sheet-like member 220 gets over the engaging portion 108, the leading end 221 of the sheet-like member 220 and By engaging the both end portions 223 with the engaging portion 108, the front end portion 221 and the both end portions 223 are reliably reversed.

  Here, in FIGS. 7B and 7C, the first protrusion 213, the second protrusion 214, and the plate shown in FIG. 7A are shown so that the relationship between the side end portions 223 and the engaging portion 108 can be easily understood. Illustration of the sponge 230 is omitted.

  Further, as shown in FIG. 8, a pair of engaging walls 102 formed so as to protrude from a pair of side walls forming the long groove 101 are formed on one end side of the long groove 101 of the upper frame 100. The engaging wall 102 comes into contact with the respective notches 224 (both side ends) of the sheet-like member 220 when the cleaning member 200 is attached to the long groove 101. The slit 226 is further opened so that the discharge wire 110 can smoothly enter the hole 225.

  Further, as shown in FIGS. 9A and 9B, a pair of tapers that push the arm portions 212 (second projections 214) of the support member 210 toward each other in the long groove 101 of the upper frame 100. A surface 103 is formed. Accordingly, after inserting the cleaning member 200 from one end side (engagement wall 102 side) of the long groove 101, the arm member of the support member 210 is slid to the other end side as shown in FIG. 9B. 212 approaches and the slit 226 of the sheet-like member 220 closes.

  Specifically, the pair of tapered surfaces 103 push each arm portion 212 (each second protrusion 214) in the approaching direction, and the two corner portions 213A and 213D (each of the first protrusions 213 provided integrally with each arm portion 212). 6) presses the two corners 227A and 227D of each engagement hole 227 of the sheet-like member 220 inward, so that the slit 226 of the sheet-like member 220 is closed. As a result, when the cleaning member 200 is positioned at the cleaning position for cleaning the grid electrode 121, the slit 226 is closed and slidably contacts the entire grid electrode 121, so that the grid electrode 121 can be cleaned well. It has become. Further, the plate-like sponge 230 (see FIG. 4) is pressed and contracted by approaching the arm portions 212 of the support member 210 in this way, so that the discharge wire 110 is strongly rubbed with the plate-like sponge 230 to improve cleaning. It is possible to do it.

According to the above, the following effects can be obtained in the present embodiment.
Since the sheet-like member 220 having different front and back roughnesses is reversed when the moving direction of the cleaning member 200 is switched, the cleaning conditions can be changed between the forward path and the return path of the cleaning member 200. In particular, in the present embodiment, the toner or the like fixed to the counter electrode 120 can be scraped off by the polishing member 250 that forms a rough surface in the forward path, and the toner or the like that is scraped off by the felt member 260 that forms a fine surface can be wiped off on the return path. The counter electrode 120 can be cleaned well.

  Since the sheet-like member 220 is configured by simply laminating members of different materials, the manufacturing operation of the sheet-like member 220 can be facilitated.

  Since the sheet-like member 220 includes the polishing member 250 and the porous felt member 260 that is softer than the polishing member 250, the effect of scraping and wiping off can be exhibited well.

  Engaging portions 108 for reversing the sheet-like member 220 by engaging with the end portions of the sheet-like member 220 are provided on both ends of the counter electrode 120, so that the sheet-like member 220 is reliably reversed. be able to.

  Since the sheet-like member 220 is configured such that the front end portion 221 contacts the grid electrode 121 and the both side end portions 223 contact the shield electrode 122, both the grid electrode 121 and the shield electrode 122 are cleaned well. be able to.

  By forming the notch portion 224 between the front end portion 221 and the side end portions 223 of the sheet-like member 220, the front end portion 221 and the side end portions 223 of the sheet-like member 220 are not affected by each other's bending. The tip 221 and both side ends 223 of the sheet-like member 220 can be brought into contact with the grid electrode 121 and the shield electrodes 122 with high accuracy. Furthermore, each of the front-end | tip part 221 and the both-sides end part 223 of the sheet-like member 220 can be reversed reliably.

  Since the cleaning member 200 includes a plate-like sponge 230 that cleans the discharge wire 110 and a sheet-like member 220 that cleans the counter electrode 120, the discharge wire 110 and the counter electrode 120 can be simply moved by moving the cleaning member 200. It can be cleaned at the same time. In addition, the sheet-like member 220 is sandwiched between the support member 210 and the plate-like sponge 230 so that the plate-like sponge 230 that cleans the discharge wire 110 prevents the sheet-like member 220 from being detached from the support member 210. Since it also serves as a member, the number of parts can be reduced.

  When the sheet-like member 220 is attached to the support member 210, the slit 226 is configured to open depending on the shape of the attachment portion between the arm portion 212 and the sheet-like member 220. Therefore, the discharge wire passes through the opened slit 226. 110 can be smoothly set in the hole 225. Therefore, the cleaning member 200 can be easily attached to the upper frame 100.

  When the cleaning member 200 is attached to the upper frame 100, the notches 224 (both side ends) of the sheet-like member 220 come into contact with the upper frame 100 to further open the slit 226, thereby discharging through the wide open slit 226. The wire 110 can be set in the hole 225 more smoothly. Therefore, the cleaning member 200 can be further easily attached.

  The open slits 226 can be closed by pushing the arm portions 212 of the support member 210 toward each other with the pair of tapered surfaces 103 of the upper frame 100, so that the leading end portion 221 of the sheet-like member 220 can be satisfactorily gridded. The electrode 121 can be slidably contacted.

  Since the sheet-like member 220 is supported by the support member 210 so as to be substantially perpendicular to the grid electrode 121 and the shield electrode 122, the front and back are reversed regardless of the direction of movement of the cleaning member 200. Switching can be performed satisfactorily.

In addition, this invention is not limited to the said embodiment, It can utilize with various forms so that it may illustrate below.
In the above-described embodiment, the polishing member 250 is also slidably contacted with the shield electrode 122. However, the present invention is not limited to this, and for example, by cutting a range of the polishing member 250 in the above-described embodiment that contacts the shield electrode 122. The film 240 may be brought into sliding contact with the shield electrode 122. According to this, the polishing member 250 becomes small, and the cost can be reduced accordingly. Even when the portion of the polishing member 250 that contacts the shield electrode 122 is cut out, the toner is less likely to adhere to the shield electrode 122 that is farther from the photoreceptor than the grid electrode 121. The shield electrode 122 can be sufficiently cleaned.

  Further, when the polishing member 250 is a sheet-shaped metal file, as shown in FIG. 10, the metal file 251 is provided only at the tip 221 of the sheet-shaped member 220, and the discharge wire 110 and the metal file 251 are connected. It is desirable to interpose an insulating plate-like sponge 230 therebetween. According to this, the insulating plate-like sponge 230 reliably prevents discharge from the discharge wire 110 to the metal file 251.

  It is desirable that the metal file 251 is formed in such a size that it is not sandwiched between the plate-like sponge 230 and the film 240, that is, a size that does not reach the surface of the plate-like sponge 230 on the film 240 side. According to this, the plate-like sponge 230 can be brought into close contact with the film 240 and the film 240 can be satisfactorily fixed to the support member 210.

  Further, at the standby position shown in FIG. 10, the metal file 251 is separated from the grid electrode 121 and comes into contact with (climbs on) the upper frame 100, so that resin (insulating) is made between the grid electrode 121 and the metal file 251. It is desirable that the upper frame 100 be interposed. Here, the “standby position” is a position on one end side of the discharge wire 110, and the cleaning member 200 waits so as not to disturb the discharge from the discharge wire 110 to the photosensitive drum 53 when the printing operation is performed. Says the position. According to this, electric leakage from the grid electrode 121 to the metal file 251 can be reliably prevented.

  In the above embodiment, the sheet-like member 220 can be turned upside down at any position of the counter electrode 120 by enabling the sheet-like member 220 to be turned upside down by friction with the counter electrode 120. It is not limited to this. That is, the sheet-like member may be reversed at least on both ends of the discharge wire, and the counter electrode and the sheet-like member may not slide and be reversed on the other side than the both ends of the discharge wire.

  In the embodiment, the roughness of the front and back surfaces of the sheet-like member 220 is made different by laminating three members, but the present invention is not limited to this. For example, the roughness of the front and back surfaces of one member (material) may be formed differently, or the roughness of the front and back surfaces of the sheet-like member may be different by stacking two members or four or more members. You may comprise.

  In the said embodiment, although the felt member 260 was employ | adopted as a 2nd member (wiping member) comprised with a porous material, this invention is not limited to this, For example, sponge etc. may be employ | adopted. In addition, the second member is not a porous material as long as the material is different from that of the first member. For example, a PET film may be employed. Even in this case, for example, the foreign material scraped by the first member can be scraped by the second member, so that it can be cleaned well.

  In the above embodiment, the sheet-like member 220 is slidably brought into contact with the grid electrode 121 and each shield electrode 122. However, the present invention is not limited to this. For example, the sheet-like member is slid only on the grid electrode or only on the shield electrode. You may contact.

  In the above-described embodiment, the engaging portion 108 that engages with the front end portion 221 of the sheet-like member 220 is formed in a protruding shape that protrudes upward. You may make it protrude diagonally upward so that 221 may enter, and you may form in a concave shape. Further, instead of forming the engaging portion 108 on the upper frame 100, the engaging portion may be provided on the counter electrode by cutting and raising a part of the counter electrode or forming it in a stepped shape.

  In the above-described embodiment, the notch 224 of the sheet-like member 220 is configured to contact the engaging wall 102 of the upper frame 100. However, the present invention is not limited to this, and may be configured not to contact. . Even in this case, when the engagement hole 227 of the sheet-like member 220 is attached to the first protrusion 213 of the support member 210, the slit 226 can be opened, so that the discharge to the hole 225 is performed through the opened slit 226. The wire 110 can enter.

  In the above embodiment, in order to configure the sheet-like member 220 so as to be able to bend and deform, the PET film 240 is used as a base. However, the present invention is not limited to this, and other resin films may be used. It may be.

In the embodiment, the notch 224 is formed as a V-shaped recess, but the present invention is not limited to this, and may be formed in a slit shape, for example.
In the above embodiment, the plate-like sponge 230 is used as the sliding contact member, but the present invention is not limited to this, and for example, a plate-like felt may be adopted.

In the above embodiment, the present invention is applied to the color printer 1. However, the present invention is not limited to this, and the present invention may be applied to other image forming apparatuses such as a copying machine and a multifunction machine.
In the above-described embodiment, the photosensitive drum 53 is employed as the photosensitive member. However, the present invention is not limited to this, and for example, a belt-shaped photosensitive member may be employed.

54 Charging device 100 Upper frame 102 Engagement wall 103 Tapered surface 108 Engagement part 110 Discharge wire 120 Counter electrode 121 Grid electrode 122 Shield electrode 200 Cleaning member 210 Support member 212 Arm part 220 Sheet-like member 221 Tip part 223 Side end part 224 Notch 226 Slit 230 Plate-like sponge 240 Film 250 Polishing member 260 Felt member

Claims (10)

A discharge wire extending along a predetermined direction;
A counter electrode extending along the extending direction of the discharge wire and facing the discharge wire;
A frame that supports the discharge wire and the counter electrode;
A charger having
A cleaning member that cleans the counter electrode by moving in the extending direction while being in sliding contact with the counter electrode,
The moving direction of the cleaning member can be selectively switched between a first direction along the extending direction and a second direction opposite to the first direction,
The cleaning member is
It has a sheet-like member that can be bent and deformed in contact with the counter electrode,
The charger is characterized in that the sheet-like member has different front and back roughness, and the portion that contacts the counter electrode is reversed when the direction of movement of the cleaning member is switched. The sheet-like member is
A first member constituting one of the front and back surfaces;
2. The charger according to claim 1, wherein the charger is configured by laminating a second member that constitutes the other surface of the front and back surfaces and is made of a material different from that of the first member. The first member is a polishing member for polishing deposits on the counter electrode,
The charger according to claim 2, wherein the second member is configured to be more flexible than the first member, and is a wiping member that wipes off deposits on the counter electrode.   The engagement part which reverses the front and back of the said sheet-like member by engaging with the said sheet-like member is provided in the both ends of the said counter electrode, The any one of Claims 1-3 characterized by the above-mentioned. The charger according to item 1. The counter electrode is
A grid electrode disposed between the discharge wire and a photosensitive member whose surface is movable and capable of carrying an electrostatic latent image on the surface;
A pair of shield electrodes positioned so as to sandwich the discharge wire in the moving direction of the surface of the photoreceptor,
The sheet-like member is configured to intersect the first end on both sides of the first end that contacts the grid electrode, and to contact the shield electrode. The charger according to claim 1, further comprising a second end portion.   The charger according to claim 5, wherein a notch is formed between the first end and the second end of the sheet-like member. The cleaning member is
A support member for supporting the sheet-like member;
A sliding contact member supported by the support member and in sliding contact with the discharge wire in the extending direction;
The charger according to claim 6, wherein the sheet-like member is sandwiched between the sliding contact member and the support member. In the sheet-like member, a hole for passing the discharge wire is formed, and a slit extending from the hole to the first end of the sheet-like member is formed,
The support member is provided with two flexibly deformable arm portions that respectively support one and the other of the sheet-like members separated by the slit,
8. The structure according to claim 7, wherein when the sheet-like member is attached to the support member, the slit is opened due to a difference in shape of an attachment portion between the arm portion and the sheet-like member. Charger.   9. The structure according to claim 8, wherein when the cleaning member is attached to the frame, the second end portion side of the sheet-like member is in contact with the frame so that the slit is further opened. The charger as described. 10. The charger according to claim 8, wherein the frame is formed with a tapered surface that pushes the arm portions in a direction in which the arm portions approach each other.

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