JP6914761B2 - Corona discharge device and image forming device equipped with it - Google Patents

Description

The present invention is a corona discharge device that performs corona discharge using a corona electrode in which a large number of sharpened tips are arranged in a row, and an electrophotographic image forming apparatus such as a copier, a multifunction device, or a printer equipped with the corona discharge device. Regarding.

Some corona discharge type corona discharge devices used in electrophotographic image forming devices perform corona discharge from a corona electrode in which a large number of sharpened tips (for example, serrated tips) are arranged in a row. There is.

In such a corona discharge device, deposits such as discharge products and toner adhere to the tip of the corona electrode as the discharge time elapses, and as a result, the discharge performance (for example, charging performance) deteriorates.

As a configuration for cleaning the tip portion of the corona electrode, for example, Patent Document 1 discloses a configuration in which the tip portion of the corona electrode is cleaned by two cleaning members provided on both side surfaces of the corona electrode.

Japanese Unexamined Patent Publication No. 2012-118308

However, in the configuration described in Patent Document 1, the configuration is complicated because two cleaning members are used.

In this regard, it is conceivable to use a cleaning member that cleans the tip of the corona electrode while reciprocating along the longitudinal direction of the corona electrode with the tip biting into the corona electrode. In this case, a single cleaning is used. Although the configuration can be simplified by using the member, when the cleaning member moves to one side in the moving direction and when the cleaning member moves to the other side in the moving direction, the cleaning member Since the cleaning position of the surface is the same (constant) in the direction intersecting the longitudinal direction of the corona electrode, the cleaning performance of the cleaning member with respect to the corona electrode deteriorates in a short period of time.

Therefore, the present invention is a corona discharge device provided with a corona electrode in which a large number of sharpened tips are arranged in a row, and while having a simple configuration, the cleaning performance of the cleaning member for the corona electrode can be maintained for a long period of time. It is an object of the present invention to provide a corona discharge device capable of being maintained and an image forming device equipped with the corona discharge device.

In order to solve the above problems, the corona discharge device according to the present invention is a corona discharge device provided with a corona electrode in which a large number of sharpened tips are arranged in a row, and the tip of the corona electrode is used. A cleaning member that cleans the tip portion while reciprocating along a predetermined movement direction in a biting state, and a displacement portion that is displaced by wear according to the number of times the cleaning member reciprocates in the movement direction. When the cleaning member moves to one side in the moving direction and when the cleaning member moves to the other side in the moving direction, the cleaning position on the surface of the cleaning member is set in the longitudinal direction of the corona electrode. The displacement portion is configured to be different in the direction of intersection with the above, and is characterized in that the cleaning position of the cleaning member is changed according to its own displacement. Further, the image forming apparatus according to the present invention is characterized by including the corona discharge apparatus according to the present invention.

According to the present invention, it is possible to maintain the cleaning performance of the cleaning roller for the corona electrode for a long period of time, even though the configuration is simple.

It is the schematic sectional drawing which looked at the image forming apparatus which concerns on this embodiment from the front. It is a schematic block diagram which shows typically the cross-sectional state of the charging apparatus in the image forming apparatus shown in FIG. It is the schematic sectional drawing which shows the part of the charging device enlarged. It is a perspective view which looked at the charging device from diagonally above on the front side. It is a figure which shows a part of the six views of a charging device, (a) is a plan view thereof, (b) is a right side view thereof, (c) is a front view thereof. Yes, (d) is a rear view thereof. It is a figure which shows a part of the six views of a charging device, (a) is the left side view, (b) is the bottom view. It is a perspective view which looked at the charging apparatus which concerns on 1st Embodiment from above on the front side. It is a schematic perspective view which shows the cleaning roller and the moving holding part part in the charging device which concerns on 1st Embodiment in an enlarged manner. It is a perspective view which looked at the cleaning roller and the moving holding part in the charging device which concerns on 1st Embodiment from below. It is a schematic side view which includes a partial cross section of the cleaning roller and the moving holding part part in the charging apparatus which concerns on 1st Embodiment, and is the figure which shows the state which the cleaning roller is cleaning a corona electrode at the 1st cleaning position. .. It is a schematic side view which includes a partial cross section of the cleaning roller and the moving holding part part in the charging apparatus which concerns on 1st Embodiment, and is the figure which shows the state which the cleaning roller is cleaning a corona electrode at the 2nd cleaning position. .. It is a schematic diagram which exaggerates the tilting state of the cleaning roller about the cleaning roller and the corona electrode in the charging apparatus which concerns on 1st Embodiment, and (a) and (b) are one side of the moving direction of the cleaning roller, respectively. It is a schematic plan view which shows the state which rotates while moving to the other side, and is cleaning the tip part of a corona electrode. It is a schematic plan view which shows the charging apparatus which concerns on 2nd Embodiment. It is a schematic diagram which exaggerates the tilting state of the corona electrode about the cleaning roller and the corona electrode in the charging apparatus which concerns on 2nd Embodiment, and (a) and (b) are one side of the moving direction of the cleaning roller, respectively. It is a schematic plan view which shows the state which rotates while moving to the other side, and is cleaning the tip part of a corona electrode. In the charging device according to the first embodiment and the second embodiment, the cleaning roller rotates while moving in the moving direction, and the displacement portion provided in the moving holding portion is in sliding contact with a part of the cleaning roller constituting the sliding contact portion. It is a schematic cross-sectional view which shows the state which is enlarged, and (a) and (b) are the figure which shows the state which the cleaning roller is moving to one side and the other side in the moving direction, respectively. FIG. 15 is a schematic cross-sectional view showing an enlarged state in which the displacement portion is worn due to the sliding contact with the sliding contact portion as the cleaning roller reciprocates in the moving direction in the configuration shown in FIG. ) Is a diagram showing a state in which the cleaning roller is moving to one side and the other side in the moving direction, respectively. In the charging device according to the third embodiment, the cleaning roller rotates while moving in the moving direction, and the displacement portion provided on the cleaning roller is in sliding contact with a part of the moving holding portion constituting the sliding contact portion. (A) and (b) are diagrams showing a state in which the cleaning roller is moving to one side and the other side in the moving direction, respectively. FIG. 17 is a schematic cross-sectional view showing an enlarged state in which the displacement portion is worn due to the sliding contact with the sliding contact portion as the cleaning roller reciprocates in the moving direction in the configuration shown in FIGS. 17 (a) and 17 (b). ) Is a diagram showing a state in which the cleaning roller is moving to one side and the other side in the moving direction, respectively. It is a schematic side view which shows an example of the index provided on the surface of a cleaning roller.

Hereinafter, a case where the corona discharge device according to the present invention is applied to a charging device will be described with reference to the drawings. In the following description, the same parts are designated by the same reference numerals. Their names and functions are the same. Therefore, the detailed description of them will not be repeated.

(Overall configuration of image forming apparatus)
FIG. 1 is a schematic cross-sectional view of the image forming apparatus 100 according to the present embodiment as viewed from the front.

The image forming apparatus 100 shown in FIG. 1 is an electrophotographic image forming apparatus using a corona discharge. In this example, the image forming apparatus 100 refers to the sheet P (recording paper in this example) such as recording paper according to the image data read by the document reading apparatus 108 or the image data transmitted from the outside. It is a color image forming apparatus for forming multicolor and monochromatic images. The image forming apparatus 100 may be a monochrome image forming apparatus. Further, the image forming apparatus 100 may be another color image forming apparatus.

The image forming apparatus 100 includes a document reading apparatus 108 and an image forming apparatus main body 110, and the image forming apparatus main body 110 is provided with an image forming unit 102 and a sheet conveying system 103.

The image forming unit 102 includes an exposure unit 1, a plurality of developing units 2 and 2, a plurality of photoconductor drums 3 and 3 acting as an electrostatic latent image carrier, a plurality of cleaning units 4 and 4, and a plurality of charging devices 5 and 5. 5 (an example of a corona charging device), an intermediate transfer belt unit 6, a plurality of toner cartridge units 21 to 21, and a fixing unit 7 are provided. Further, the sheet transport system 103 includes a paper feed tray 81, a manual paper feed tray 82, and a discharge tray 15.

A document mounting table 92 made of transparent glass on which a document (not shown) is placed is provided on the upper portion of the image forming apparatus main body 110, and an optical unit 90 for reading the document is provided on the lower portion of the document mounting table 92. Has been done. Further, a document reading device 108 is provided on the upper side of the document mounting table 92. The image of the original document read by the document reading device 108 is sent to the image forming apparatus main body 110 as image data, and the image formed based on the image data in the image forming apparatus main body 110 is recorded on the sheet P.

The image data handled by the image forming apparatus 100 corresponds to a color image using a plurality of colors (in this example, each color of black (K), cyan (C), magenta (M), and yellow (Y)). .. Therefore, the developing units 2 to 2, the photoconductor drums 3 to 3, the cleaning units 4 to 4, the charging devices 5 to 5, and the toner cartridge units 21 to 21 are images of a plurality of types (4 types in this example) according to each color. Each is set to a plurality (4 each in this example, black, cyan, magenta, and yellow, respectively) so as to form a plurality of (4 in this example) image stations.

In the image forming apparatus 100, when forming an image, the sheet P is supplied from the paper feed tray 81 or the manual paper feed tray 82, and the sheet up to the resist roller 13 is supplied by the first transport roller 12a provided along the sheet transport path S. Transport P. Next, the sheet P is conveyed by the transfer roller 10 at the timing of matching the toner image on the intermediate transfer belt 61 that is orbitably moved in the circumferential direction V between the sheet P and the intermediate transfer belt unit 6, and the toner image is transferred onto the sheet P. Transcribe. After that, by passing the sheet P through the heat roller 71 and the pressure roller 72 in the fixing unit 7, the unfixed toner on the sheet P is melted and fixed by heat, and the discharge tray passes through the second transport roller 12b and the discharge roller 31. Discharge on 15.

Next, the charging devices 5 to 5 that act as the corona discharge device will be described below with reference to FIGS. 2 to 17.

(Charging device)
FIG. 2 is a schematic configuration diagram schematically showing a cross-sectional state of the charging device 5 in the image forming device 100 shown in FIG. FIG. 3 is a schematic cross-sectional view showing a part of the charging device 5 in an enlarged manner. FIG. 4 is a perspective view of the charging device 5 viewed from diagonally above on the front side. 5 and 6 are views showing a part of the hexagonal view of the charging device 5. 5 (a) is a plan view thereof, FIG. 5 (b) is a right side view thereof, FIG. 5 (c) is a front view thereof, and FIG. 5 (d) is a rear view thereof. 6 (a) is a left side view thereof, and FIG. 6 (b) is a bottom view thereof. In a part of FIGS. 4 and 5A, the grid electrode 53 is not shown. Since the charging devices 5 to 5 are substantially the same, they are shown in one figure in FIGS. 2 to 6. The same applies to FIGS. 7 to 19 described later.

The charging device 5 includes a corona electrode 51 in which a large number of sharpened tip portions 51a to 51a are arranged in a row, and a main body portion (specifically, a main body case) 52 that supports the corona electrode 51. In this example, the charging device 5 is of the scorotron type, further including a grid electrode 53 for controlling the charging potential of the surface 3a of the photoconductor drum 3.

The corona electrode 51 extends in parallel or substantially parallel to the rotation axis direction X of the photoconductor drum 3, and is arranged in the main body 52. In this example, the corona electrode 51 is an electrode in which a large number of serrated (triangular side view) tip portions 51a to 51a are formed at predetermined pitch intervals Pt (see FIG. 3) along the longitudinal direction N. (So-called sawtooth electrode or needle electrode).

The main body 52 is a box-shaped member that extends parallel to or substantially parallel to the rotation axis direction X of the photoconductor drum 3 and has an open surface on the side facing the photoconductor drum 3. The grid electrode 53 is provided so as to cover the open side of the main body 52. The corona electrode 51 is provided on the main body 52 so that the tip 51a faces the surface 3a of the photoconductor drum 3 via the grid electrode 53.

Specifically, the main body 52 is attached to and detached from the image forming apparatus main body 110 so that the distance D1 (see FIG. 2) between the grid electrode 53 and the surface 3a of the photoconductor drum 3 is uniform or substantially uniform in the longitudinal direction N. It is provided freely. Further, the corona electrode 51 is fixed to the main body 52 so that the distance D2 (see FIG. 2) between the tip 51a and the grid electrode 53 is uniform or substantially uniform in the longitudinal direction N. As a result, the charging device 5 can uniformly generate corona discharge from the corona electrode 51 toward the grid electrode 53 along the longitudinal direction N. The corona electrode 51 can be formed, for example, by etching a metal material (specifically, stainless steel) having a plate thickness of a predetermined thickness (specifically, about 0.1 mm). Further, the corona electrode 51 can be formed so that the radius of curvature of the tip portion 51a is, for example, a predetermined value (specifically, about 20 μm) or less.

The grid electrode 53 is configured so that the corona wind generated by the corona discharge by the corona electrode 51 is smoothly supplied to the photoconductor drum 3. In this example, the grid electrodes 53 are formed in a mesh shape [see FIG. 5 (a)].

A DC voltage is applied to the corona electrode 51 and the grid electrode 53, respectively, via a power supply (not shown) so as to generate a preset voltage difference. Specifically, a negative-polarity DC voltage is applied to the corona electrode 51, while a positive-polarity DC voltage is applied to the grid electrode 53. As a result, a corona discharge can be generated between the corona electrode 51 and the grid electrode 53 to generate a corona wind from the corona electrode 51 to the grid electrode 53, and the photoconductor drum 3 is stably charged. be able to. Here, the preset voltage difference can be, for example, -4KV.

[First to third embodiments]
The charging device 5 can be configured according to the following first to third embodiments. Reference numerals not described in FIGS. 2 to 6 described above will be described later.

(1st embodiment and 2nd embodiment)
FIG. 7 is a perspective view of the charging device 5 according to the first embodiment as viewed from above on the front side. FIG. 8 is a schematic perspective view showing an enlarged portion of the cleaning roller 54 and the moving holding portion 55 portion in the charging device 5 according to the first embodiment. FIG. 9 is a perspective view of the cleaning roller 54 and the moving holding portion 55 in the charging device 5 according to the first embodiment as viewed from below. 10 and 11 are schematic side views including a partial cross section of the cleaning roller 54 and the moving holding portion 55 portion in the charging device 5 according to the first embodiment. FIG. 10 shows a state in which the cleaning roller 54 is cleaning the corona electrode 51 at the first cleaning position α1, and FIG. 11 shows a state in which the cleaning roller 54 is cleaning the corona electrode 51 at the second cleaning position α2. Indicates the state. FIG. 12 is a schematic view showing an exaggerated tilted state of the cleaning roller 54 and the corona electrode 51 in the charging device 5 according to the first embodiment. 12 (a) and 12 (b) show a state in which the cleaning roller 54 rotates while moving to one side M1 and the other side M2 in the moving direction M to clean the tip portion 51a of the corona electrode 51, respectively. It is a schematic plan view which shows.

Further, FIG. 13 is a schematic plan view showing the charging device 5 according to the second embodiment. FIG. 14 is a schematic view showing an exaggerated tilted state of the corona electrode 51 with respect to the cleaning roller 54 and the corona electrode 51 in the charging device 5 according to the second embodiment. 14 (a) and 14 (b) show a state in which the cleaning roller 54 rotates while moving to one side M1 and the other side M2 in the moving direction M to clean the tip portion 51a of the corona electrode 51, respectively. It is a schematic plan view which shows.

In FIG. 15, in the charging device 5 according to the first embodiment and the second embodiment, the cleaning roller 54 rotates while moving in the moving direction M, and the displacement portion 58 provided in the moving holding portion 55 makes the sliding contact portion 59. It is an enlarged schematic cross-sectional view which shows the state of sliding contact with a part of the cleaning roller 54 which constitutes. 15 (a) and 15 (b) show a state in which the cleaning roller 54 is moving to one side M1 and the other side M2 in the moving direction M, respectively.

FIG. 16 is a schematic cross-sectional view showing an enlarged state in which the displacement portion 58 is worn by the sliding contact with the sliding contact portion 59 as the cleaning roller 54 reciprocates in the moving direction M in the configuration shown in FIG. .. 16 (a) and 16 (b) show a state in which the cleaning roller 54 is moving to one side M1 and the other side M2 in the moving direction M, respectively.

The charging device 5 further includes a cleaning roller 54 (an example of a cleaning member), a displacement portion 58, and a moving holding portion 55. The cleaning roller 54 is provided along a predetermined movement direction M (in this example, a direction parallel to or substantially parallel to the rotation axis direction X of the photoconductor drum 3) in a state where the tip portion 51a of the corona electrode 51 is bitten into the cleaning roller 54. The tip portion 51a is cleaned while moving back and forth. The displacement portion 58 is displaced as the cleaning roller 54 reciprocates in the moving direction M. The moving holding portion 55 holds the cleaning roller 54 and is provided so as to reciprocate with respect to the main body portion 52 along the moving direction M.

In the present embodiment, the cleaning roller 54 rotates around the axis while reciprocating along the moving direction M in a state where the tip portion 51a of the corona electrode 51 is bitten to clean the tip portion 51a. Therefore, the moving holding portion 55 is configured to rotatably hold the cleaning roller 54 around the rotation axis.

Specifically, the main body 52 is provided with a guide portion 521 that guides the movement holding portion 55 in the movement direction M so as to be reciprocally movable.

The charging device 5 may manually reciprocate the movement holding unit 55 along the guide unit 521, but in this example, the movement holding unit 55 is guided by the drive unit 56 (see FIG. 4). It is designed to automatically reciprocate along the portion 521.

Specifically, the guide portion 521 extends along the moving direction M and is formed at a predetermined pitch along one side surface 52a of the main body portion 52. The male screw-shaped (spiral) engaging portion 521a It is a screw member having (more specifically, a spiral uneven portion).

The cleaning roller 54 has a cylindrical shape and is formed of an elastic member (for example, an elastic resin member such as a rubber member). The cleaning roller 54 is a single one in this example. Examples of the material that can be used for the roller portion 54c of the cleaning roller 54 include, but are not limited to, CR rubber (chloroprene rubber), urethane rubber, nitrile rubber, natural rubber, ethylene / propylene rubber, butyl rubber, and silicone. .. Further, for the roller portion 54c, for example, an elastic member containing an abrasive such as aluminum oxide (alumina) can be used.

The guide portion 521 is provided on the main body portion 52 so as to be rotatable around an axis. In this example, the guide portion 521 is a support portion 52b (more specifically, a support plate) and a support portion M2 provided at the end of one side M1 (front side, operation side) of the movement direction M of the guide portion 521. It is rotatably supported around the axis by a support portion 52c (more specifically, a support plate) provided at an end portion (on the back side, opposite to the operation side).

The drive unit 56 transmits the rotational driving force to the guide unit 521 via the drive transmission mechanism 57 (see FIG. 4). In this example, the drive transmission mechanism 57 is a drive-side gear 57a (see FIG. 4) fixed to a rotation shaft 56a (see FIG. 4) of the drive unit 56, and a rotation shaft 521b (see FIG. 4) of the guide unit 521. It includes a driven side gear 57b (see FIG. 4) that is fixed to one end and meshes with the drive side gear 57a.

The moving holding portion 55 includes a tubular portion 551 having a female screw-shaped (spiral) locking portion 551a (more specifically, a spiral concavo-convex portion) on the inner peripheral surface. In the tubular portion 551, the locking portion 551a is locked to the engaging portion 521a in the guide portion 521 by the rotation of one rotation direction R1 (clockwise in FIG. 4 in this example) around the axis of the guide portion 521. It is guided to one side M1 of the moving direction M. On the other hand, in the tubular portion 551, the locking portion 551a engages with the engaging portion 521a in the guide portion 521 due to the rotation of the other rotation direction R2 (counterclockwise in FIG. 4 in this example) around the axis of the guide portion 521. While being stopped, it is guided to the other side M2 of the moving direction M.

At the end of one side M1 of the rotation shaft 521b of the guide portion 521 in the movement direction M, the locking portion 551a in the tubular portion 551 when the movement holding portion 55 moves to the end of the one side M1 in the movement direction M. An urging member SP (specifically, a series-wound spring) that urges the guide portion 521 toward the other side M2 in the moving direction M is inserted so as not to disengage from the engaging portion 521a. As a result, it is possible to effectively prevent the movement holding portion 55 from moving too much toward one side M1 of the movement direction M due to the rotation of one rotation direction R1 around the axis of the guide portion 521, and the axis of the guide portion 521. By rotating the other rotating direction R2, the movement holding portion 55 can be easily returned to the other side M2 in the moving direction M. In this example, the urging member SP is inserted between the engaging portion 521a and the supporting portion 52b in the guide portion 521.

The reciprocating movement between the end of one side M1 of the movement direction M and the end of the other side M2 of the movement direction M by the guide portion 521 of the movement holding unit 55 is the initial position (home position: in this example, the movement direction M). The driving time to the driving unit 56 (specifically, the number of pulses of the pulse signal input to the driving unit 56) is used as a reference (the position of the end portion of the other side M2).

The moving holding portion 55 includes a support portion 552 that rotatably supports the rotating shaft 54b of the cleaning roller 54 at both ends in the rotation axis direction W, and a connecting portion 553 that connects the supporting portion 552 and the tubular portion 551. is doing. In this example, the support portion 552 is orthogonal to or orthogonal to the support plates 552a and 552b and the pair of support plates 552a and 552b that rotatably support the rotating shaft 54b of the cleaning roller 54 so as to face each other with the cleaning roller 54 in between. It has a connecting plate 552c that connects a pair of support plates 552a and 552b substantially orthogonally to each other. The connecting portion 553 is formed in a substantially L shape between the support portion 552 and the tubular portion 551 so as to straddle one side surface 52a of the main body portion 52.

In the charging device 5 having such a configuration, the drive unit 56 rotates the guide unit 521 in one rotation direction R1 around the axis, so that the guide unit 521 moves to one side M1 in the movement direction M and the cleaning roller 54 moves. While cleaning the tip portion 51a of the corona electrode 51 while biting into it, the guide portion 521 is rotated in the other rotation direction R2 around the axis by the drive unit 56, so that the guide portion 521 moves to the other side M2 in the movement direction M. While cleaning, the cleaning roller 54 bites into the tip portion 51a of the corona electrode 51 for cleaning.

Then, the charging device 5 receives the surface 54a (cleaning) of the cleaning roller 54 when the cleaning roller 54 moves to one side M1 in the moving direction M and when the cleaning roller 54 moves to the other side M2 in the moving direction M. The cleaning position (in this example, a predetermined first cleaning position α1 and a predetermined second cleaning position α2 in the rotation axis direction W of the cleaning roller 54) intersects the longitudinal direction N of the corona electrode 51. It is configured to be different in the direction of cleaning. Further, the displacement portion 58, which is displaced as the cleaning roller 54 reciprocates in the moving direction M, changes the cleaning position of the cleaning roller 54 (in this example, the first cleaning position α1 and the second cleaning position α2) according to its own displacement. do.

According to the present embodiment, the cleaning roller 54 acting as a cleaning member cleans the tip portion 51a while reciprocating along the movement direction M with the tip portion 51a of the corona electrode 51 biting into the cleaning roller 54. The tip portion 51a of the corona electrode 51 can be cleaned by using one cleaning roller 54, whereby the configuration can be simplified. Moreover, when the cleaning roller 54 moves to one side M1 in the moving direction M and when the cleaning roller 54 moves to the other side M2 in the moving direction M, the cleaning position of the surface 54a of the cleaning roller 54 (in this example). Since the first cleaning position α1 and the second cleaning position α2) are configured to be different in the direction intersecting the longitudinal direction N of the corona electrode 51, the cleaning roller 54 cleans the corona electrode 51 in order to clean the corona electrode 51. The surface 54a (unused portion) can be widely used, whereby the cleaning performance of the cleaning roller 54 with respect to the corona electrode 51 can be maintained for a long period of time.

By the way, if the displacement portion 58 is not provided, the cleaning width of the cleaning roller 54 is limited. Therefore, if the number of reciprocating movements of the cleaning roller 54 in the moving direction M increases, the cleaning roller 54 is significantly damaged within the limited cleaning width. Therefore, the cleaning performance is deteriorated.

In this respect, the displacement portion 58, which is displaced as the cleaning roller 54 reciprocates in the moving direction M, changes the cleaning position of the cleaning roller 54 according to its own displacement. Therefore, cleaning is performed as the cleaning roller 54 reciprocates in the moving direction M. The cleaning position of the roller 54 can be changed. Therefore, the cleaning width of the cleaning roller 54 can be expanded, and the surface 54a (unused portion) of the cleaning roller 54 can be used more widely in order to clean the tip portion 51a of the corona electrode 51 by the cleaning roller 54. As a result, the cleaning performance of the cleaning roller 54 with respect to the corona electrode 51 can be maintained for a longer period of time.

In the present embodiment, the cleaning roller 54 is provided with a sliding contact portion 59 that is in sliding contact with the displacement portion 58 by reciprocating in the moving direction M. The displacement portion 58 is worn due to the sliding contact with the sliding contact portion due to the reciprocating movement of the cleaning roller 54 in the moving direction M. By doing so, it is possible to easily realize a configuration in which the displacement portion 58 is displaced.

In the present embodiment, the cleaning roller 54 rotates while reciprocating along the moving direction M with the tip portion 51a of the corona electrode 51 biting into the cleaning roller 54 to clean the tip portion 51a.

In such a configuration, the cleaning portion of the surface 54a of the cleaning roller 54 to the corona electrode 51 can be used over the entire outer circumference of the surface 54a, and the cleaning performance can be maintained for a long period of time.

Then, the displacement portion 58 is brought into sliding contact with the sliding contact portion 59 by the rotation of the cleaning roller 54. By doing so, the displacement portion 58 can be reliably worn by utilizing the rotation of the cleaning roller 54, and the cleaning width of the cleaning roller 54 can be easily adjusted according to the number of reciprocating movements of the cleaning roller 54 in the moving direction M. Can be expanded.

Further, the charging device 5 is other than a predetermined inclination angle θ (0 °, ± 90 ° and 180 °) in which the rotation axis direction W of the cleaning roller 54 and the orthogonal direction H orthogonal to the longitudinal direction N of the corona electrode 51 are predetermined. It is configured to intersect at (angle). The charging device 5 shifts the cleaning position of the surface 54a of the cleaning roller 54 to one side W1 in the rotation axis direction W (specifically, one side W1 by a predetermined distance d) by the rotation of one rotation direction S1 of the cleaning roller 54. It is configured so that the displacement portion 58 is slidably contacted with the sliding contact portion 59 by shifting. Further, the charging device 5 sets the cleaning position of the surface 54a of the cleaning roller 54 by the rotation of the other rotation direction S2 of the cleaning roller 54 to the other side W2 in the rotation axis direction W (specifically, the other side W2 by a predetermined distance d). ), And the displacement portion 58 is slidably contacted with the sliding contact portion 59. By doing so, the displacement portion 58 can be stably slidably contacted with the sliding contact portion 59. Here, the predetermined distance d is a value smaller than the width h (see FIG. 9) in the rotation axis direction W of the cleaning roller 54.

In the charging device 5 according to the first embodiment shown in FIGS. 7 to 12, 15 and 16, the longitudinal direction N of the corona electrode 51 is parallel or substantially parallel to the moving direction M, and the cleaning roller 54 The rotation axis direction W of is inclined with respect to the movement direction M.

By doing so, the support of the corona electrode 51 to the main body 52 can be realized with a simple configuration.

In the charging device 5 according to the second embodiment shown in FIGS. 13 to 16, the longitudinal direction N of the corona electrode 51 is inclined with respect to the moving direction M, and the rotation axis direction W of the cleaning roller 54 is in the moving direction M. On the other hand, it is at a right angle or almost at a right angle.

By doing so, the cleaning roller 54 can be held by the moving holding portion 55 with a simple configuration.

In the first embodiment and the second embodiment, the displacement portion 58 is provided in the moving holding portion 55, and a part of the cleaning roller 54 constitutes the sliding contact portion 59. By doing so, the sliding contact structure between the displacement portion 58 and the sliding contact portion 59 can be easily realized.

Specifically, the displacement portion 58 is provided on the inner wall surface of the first regulation portion 55a (specifically, the support plate 552a) and the second regulation portion 55b (specifically, the support plate 552b) on both sides of the movement holding portion 55. ing. A part of the outer surface of the shaft end portion ST1 and the shaft end portion ST2 on both sides of the rotating shaft 54b of the cleaning roller 54 is a sliding contact portion 59.

One displacement portion 58 is provided on at least one side (both sides in this example) of both sides of the movement holding portion 55. In addition, two or more displacement portions 58 may be evenly provided in the circumferential direction on at least one side of both sides of the movement holding portion 55.

In the charging device 5 according to the first embodiment and the second embodiment shown in FIGS. 7 to 16, the cleaning roller 54 freely shifts to the corona electrode 51 along the rotation axis direction W. The rotating shaft 54b of the cleaning roller 54 is a predetermined predetermined position between the shaft end portion ST1 and the shaft end portion ST2 and the first regulating portion 55a on both sides of the moving holding portion 55 and the displacement portion 58 of the second regulating portion 55b. It is rotatably supported by the moving holding portion 55 with intervals e and e (so-called play) provided. By doing so, the cleaning roller 54 can be reliably moved to both one side W1 and the other side W2 in the rotation axis direction W by the movement holding portion 55.

The charging device 5 according to the first embodiment and the second embodiment has a configuration in which the cleaning roller 54 is held by the moving holding portion 55 so as to be movable along the rotation axis direction W, and the corona electrode 51 is fixed. ing.

In the charging device 5 according to the first embodiment and the second embodiment described above, when the cleaning roller 54 moves to one side M1 in the moving direction M, the cleaning roller 54 moves to the one side M1 and the cleaning roller 54 moves to the corona electrode. The tip 51a of the corona electrode 51 is obliquely contacted with the 51 (that is, the tip 51a of the corona electrode 51 is obliquely bitten into the surface 54a of the cleaning roller 54), and the rotor electrode 51 is rotated in one of the rotation directions S1.

Then, the cleaning roller 54 shifts to the other side W2 (the side forming the inclination angle θ on the upstream side in the one side M1 of the moving direction M) in the rotation axis direction W, and then the rotation shaft 54b of the cleaning roller 54 moves to the other side. By being regulated by the displacement portion 58 in the regulating portion (in this example, the second regulating portion 55b on the other side) that regulates the transition to W2, the transition to the other side W2 in the rotation axis direction W is performed at the first cleaning position α1. Stop. As a result, the cleaning roller 54 can clean the tip portion 51a of the corona electrode 51 at the first cleaning position α1. At this time, the displacement portion 58 is in sliding contact with the sliding contact portion 59 and is worn.

On the other hand, when the cleaning roller 54 moves to the other side M2 in the moving direction M, the cleaning roller 54 is in oblique contact with the corona electrode 51 as it moves to the other side M2 (that is, the corona electrode 51 is brought into contact with the cleaning roller 54. (While biting into the surface 54a at an angle), it rotates in the other rotation direction S2.

Then, the cleaning roller 54 shifts to one side W1 (the side forming the inclination angle θ on the upstream side in the other side M2 of the moving direction M) in the rotation axis direction W, and then the rotation shaft 54b of the cleaning roller 54 moves to one side. The transition to one side W1 in the rotation axis direction W is defined as the first cleaning position α1 by being regulated by the displacement portion 58 in the regulation portion (in this example, the first regulation portion 55a on one side) that regulates the transition to W1. Stops at a different second cleaning position α2. As a result, the cleaning roller 54 can clean the tip portion 51a of the corona electrode 51 at the second cleaning position α2. At this time, the displacement portion 58 is in sliding contact with the sliding contact portion 59 and is worn.

Thus, when the cleaning roller 54 moves to one side M1 in the moving direction M and when the cleaning roller 54 moves to the other side M2 in the moving direction M, the cleaning position (α1, α2) of the surface 54a of the cleaning roller 54 ) Are different in the direction intersecting the longitudinal direction N of the corona electrode 51, can be easily and easily realized.

Here, the inclination angle θ in the first embodiment and the second embodiment allows the corona electrode 51 to be reliably cleaned by the cleaning roller 54, and different cleaning positions (α1, α2) on the surface 54a of the cleaning roller 54. The angle can be set so that the transition can be made smoothly. The inclination angle θ in the first embodiment is not limited to, but is not limited to, depending on the width h of the cleaning roller 54 and the like, but is more preferably about 1 ° or more and 5 ° or less, more preferably about 1 ° or more and 3 ° or less. It can be illustrated, and in this example, it is set to about 2 °. The inclination angle θ in the second embodiment is not limited to, but is not limited to, depending on the length of the corona electrode 51 and the like, but is about 0.1 ° or more and 0.5 ° or less, more preferably 0. About 1 ° or more and 0.3 ° or less can be exemplified, and in this example, it is about 0.2 °.

(Third Embodiment)
In the charging device 5 according to the third embodiment, in the charging device 5 according to the first embodiment and the second embodiment, the displacement portion 58 is provided on the cleaning roller 54 instead of the moving holding portion 55, and the cleaning roller 54 is replaced. A part of the moving holding portion 55 constitutes the sliding contact portion 59.

In FIG. 17, in the charging device 5 according to the third embodiment, the cleaning roller 54 rotates while moving in the moving direction M, and the displacement portion 58 provided on the cleaning roller 54 constitutes the sliding contact portion 59. It is a schematic cross-sectional view which shows the state of sliding contact with a part of. 17 (a) and 17 (b) show a state in which the cleaning roller 54 is moving to one side M1 and the other side M2 in the moving direction M, respectively.

FIG. 18 is a schematic cross-sectional view showing an enlarged state in which the displacement portion 58 is worn by the sliding contact with the sliding contact portion 59 as the cleaning roller 54 reciprocates in the moving direction M in the configuration shown in FIG. .. 18 (a) and 18 (b) show a state in which the cleaning roller 54 is moving to one side M1 and the other side M2 in the moving direction M, respectively.

In the present embodiment, the displacement portion 58 is provided on the cleaning roller 54, and a part of the moving holding portion 55 constitutes the sliding contact portion 59. By doing so, the sliding contact structure between the displacement portion 58 and the sliding contact portion 59 can be easily realized. Further, when the displacement portion 58 is provided on the cleaning roller 54 as in this example, the displacement portion 58 can be replaced together with the cleaning roller 54 when the cleaning roller 54 should be replaced.

Specifically, the displacement portions 58 are provided on the outer surfaces of the shaft end portions ST1 and the shaft end portions ST2 provided on both sides of the rotating shaft 54b of the cleaning roller 54. A part of the inner wall surface of the first regulating portion 55a (specifically, the support plate 552a) and the second regulating portion 55b (specifically, the support plate 552b) on both sides of the moving holding portion 55 is a sliding contact portion 59. There is.

One displacement portion 58 is provided on at least one side (both sides in this example) of both sides of the rotating shaft 54b of the cleaning roller 54. Two or more displacement portions 58 may be evenly provided in the circumferential direction on at least one of both sides of the rotating shaft 54b of the cleaning roller 54.

(Common configuration of the first to third embodiments)
In the first to third embodiments, the displacement portion 58 is a protrusion. By doing so, the displacement portion 58 can be easily and easily formed. The protrusion is not limited to that, and examples thereof include a cylindrical shape, a prismatic shape, a hemispherical shape, a semi-elliptical shape, a conical shape, and a pyramid shape.

In the first to third embodiments, the displacement portion 58 is made of a resin material. By doing so, the displacement portion 58 can be easily worn. The resin material can be appropriately determined depending on the material and properties of the sliding contact portion 59, and is not particularly limited. Examples of the sliding contact portion 59 include a resin material and a metal material. For example, when the displacement portion 58 is provided in the moving holding portion 55 and a part of the rotating shaft 54b of the cleaning roller 54 constitutes the sliding contact portion 59, the displacement portion 58 and the moving holding portion 55 are made of a resin material, and the rotating shaft 54b is used. Can be exemplified by using the above as a metal material. In this case, the displacement portion 58 and the movement holding portion 55 can be integrally formed. Further, when the displacement portion 58 is provided on the rotating shaft 54b of the cleaning roller 54 and a part of the moving holding portion 55 constitutes the sliding contact portion 59, the displacement portion 58, the rotating shaft 54b and the moving holding portion 55 are made of a resin material. The embodiment to be used can be exemplified. In this case, the displacement portion 58 and the rotating shaft 54b can be integrally formed.

In the first to third embodiments, at least the portion of the sliding contact portion 59 that is in sliding contact with the displacement portion 58 is formed in an uneven shape. By doing so, the friction coefficient (particularly the dynamic friction coefficient) between the displacement portion 58 and the sliding contact portion 59 at least the displacement portion 58 and the sliding contact portion can be increased, whereby the displacement portion 58 can be easily worn. Can be done. The uneven shape of the sliding contact portion 59 is not limited to that, and examples thereof include curved surface-shaped unevenness, square-shaped unevenness, and triangular-shaped unevenness. Examples of the uneven shape of the sliding contact portion 59 include those formed by processing (for example, embossing) to form the uneven shape using a mold having an uneven surface. In addition, the uneven shape of the sliding contact portion 59 may be formed so that a sharp blade stands up, or may be formed by applying an abrasive to the surface.

In the first to third embodiments, the wear resistance of the displacement portion 58 is smaller than the wear resistance of the sliding contact portion 59. By doing so, the displacement portion 58 can be reliably worn. Abrasion resistance can be measured, for example, according to ISO 9352 standard.

The amount of wear of the displacement portion 58 per number of movements of the cleaning roller 54 can be appropriately set from the number of movements of the cleaning roller 54 capable of maintaining the cleaning ability with respect to the tip portion 51a of the corona electrode 51.

FIG. 19 is a schematic side view showing an example of the index G provided on the surface 54a of the cleaning roller 54. In FIG. 19, reference numeral G indicates an index indicating the degree of wear of the displacement portion 58, and reference numeral F indicates a corona on the surface 54a of the cleaning roller 54 when the displacement portion 58 is most displaced (when worn). The reference numerals α1 (α1a) and α2 (α2a) indicate the initial first cleaning position and the second cleaning position, respectively, and the reference numerals α1 (α1b) and α2 (α2b) indicate the range of damage caused by the electrode 51. , The first cleaning position and the second cleaning position when the displacement portion 58 is most displaced are shown.

In the first to third embodiments, as shown in FIG. 19, the cleaning roller 54 is provided with an index G indicating the degree of wear of the displacement portion 58. By doing so, it is possible to inform a worker such as a serviceman of a guideline for the replacement time of the cleaning roller 54. Here, the index G can be located at the end position of the range F of the damage caused by the corona electrode 51 on the surface 54a of the cleaning roller 54 when the displacement portion 58 is most displaced. Therefore, the guideline for the replacement time of the cleaning roller 54 is when the damage range F reaches the position of the index G. In this example, the surface 54a of the cleaning roller 54 has a line drawn in the circumferential direction so that the degree of wear of the displacement portion 58 can be seen. However, the index G is not limited to this, and the index G may be, for example, an index such as an arrow instead of the line.

(Other embodiments)
The configurations of the first embodiment and the second embodiment and the configurations of the third embodiment may be combined. In the present embodiment, the cleaning roller 54 is automatically reciprocated along the moving direction M, but it may be manually reciprocated. Further, the intersecting direction of the rotation axis direction W of the cleaning roller 54 and the longitudinal direction N of the corona electrode may be reversed. Further, although the cleaning roller 54 is a single one, a plurality of cleaning rollers 54 may be arranged along the longitudinal direction N of the corona electrodes.

Further, in the present embodiment, the corona discharge device according to the present invention is applied to the charging device 5 that charges the photoconductor drum 3 to a predetermined potential, but any one can be used as long as it discharges the corona. Alternatively, for example, it may be applied to a charging device that charges the surface of the intermediate transfer belt by corona discharge.

The present invention is not limited to the embodiments described above, and can be implemented in various other forms. Therefore, such embodiments are merely exemplary in all respects and should not be construed in a limited way. The scope of the present invention is shown by the claims and is not bound by the text of the specification. Furthermore, all modifications and modifications that fall within the equivalent scope of the claims are within the scope of the present invention.

100 Image forming apparatus 110 Image forming apparatus main body 3 Photoreceptor drum (example of electrostatic latent image carrier)
5 Charging device 51 Corona electrode 51a Tip part 52 Main body part 521 Guide part 54 Cleaning roller (example of cleaning member)
54a Surface 54b Rotating shaft 54c Roller part 55 Moving holding part 56 Driving part 57 Drive transmission mechanism 58 Displacement part 59 Sliding contact part D1 Interval D2 Interval F Damage range G Index H Orthogonal direction M Moving direction N Longitudinal direction ST1 Shaft end ST2 Shaft end W Rotation axis direction d Distance e Interval α1 First cleaning position α2 Second cleaning position θ Tilt angle

Claims (11)

A corona discharge device equipped with a corona electrode in which a large number of sharpened tips are arranged in a row.
According to a cleaning member that cleans the tip while reciprocating along a predetermined movement direction with the tip of the corona electrode biting into the corona electrode, and the number of times the cleaning member reciprocates in the movement direction. Equipped with a displacement part that displaces due to wear,
When the cleaning member moves to one side in the moving direction and when the cleaning member moves to the other side in the moving direction, the cleaning position on the surface of the cleaning member intersects with the longitudinal direction of the corona electrode. It is configured to be different in the direction of cleaning,
The displacement portion is a corona discharge device characterized in that the cleaning position of the cleaning member is changed according to its own displacement. The corona discharge device according to claim 1.
A sliding contact portion that slides into contact with the displacement portion by reciprocating the cleaning member in the moving direction is provided.
A corona discharge device characterized in that the displacement portion is worn by sliding contact with the sliding contact portion as the cleaning member reciprocates in the moving direction. The corona discharge device according to claim 2.
The cleaning member is a cleaning roller that rotates while reciprocating along the moving direction in a state where the tip of the corona electrode is bitten into the tip to clean the tip.
A corona discharge device characterized in that the displacement portion is brought into sliding contact with the sliding contact portion by rotation of the cleaning roller. The corona discharge device according to claim 3.
The rotation axis direction of the cleaning roller and the orthogonal direction orthogonal to the longitudinal direction of the corona electrode intersect at a predetermined inclination angle.
By rotating one of the cleaning rollers in the rotation direction, the cleaning position on the surface of the cleaning roller is shifted to one side in the rotation axis direction so that the displacement portion is brought into sliding contact with the sliding contact portion, and the cleaning roller The cleaning position on the surface of the cleaning roller is shifted to the other side in the direction of the rotation axis by rotation in the other rotation direction, and the displacement portion is slidably contacted with the sliding contact portion. Corona discharge device. The corona discharge device according to claim 4.
The main body that supports the corona electrode and
The cleaning roller is rotatably held around the axis of rotation, and is provided with a moving holding portion that is rotatably provided with respect to the main body portion along the moving direction.
The cleaning roller is configured to be held by the moving holding portion so as to be movable along the direction of the rotation axis.
A corona discharge device characterized in that the displacement portion is provided on the cleaning roller or the moving holding portion, and a part of the moving holding portion or the cleaning roller constitutes the sliding contact portion. The corona discharge device according to any one of claims 2 to 5.
The displacement portion is a corona discharge device characterized by being a protrusion. The corona discharge device according to any one of claims 2 to 6.
The displacement portion is a corona discharge device characterized in that it is made of a resin material. The corona discharge device according to any one of claims 2 to 7.
A corona discharge device characterized in that at least a portion of the sliding contact portion that is in sliding contact with the displacement portion is formed in an uneven shape. The corona discharge device according to any one of claims 2 to 8.
A corona discharge device characterized in that the wear resistance of the displacement portion is smaller than the wear resistance of the sliding contact portion. The corona discharge device according to any one of claims 2 to 9.
The corona discharge device is characterized in that the cleaning member is provided with an index indicating the degree of wear of the displaced portion. An image forming apparatus comprising the corona discharge apparatus according to any one of claims 1 to 10.

Images