JP2016218234A - Charging device and image forming apparatus - Google Patents

Abstract

CONSTITUTION: A charger 16 comprises a grid electrode 100, a discharge wire 50, and cleaning members. The grid electrode is formed in an endless belt shape and laid over a drive roller 56 and a driven roller 58 to be capable of a circular movement. The discharge wire extends in the longitudinal direction of a photoreceptor 12 and is arranged inside the grid electrode. The cleaning members are provided respectively on the inner peripheral surface and outer peripheral surface of the grid electrode. When the grid electrode is circularly moved by the plurality of rollers, foreign substances adhered to the grid electrode are removed by the cleaning members.EFFECT: A charging device can appropriately clean a grid electrode to maintain charging performance over a long period.SELECTED DRAWING: Figure 3

Description

  The present invention relates to a charging device and an image forming apparatus, and more particularly to a charging device and an image forming apparatus that are provided in an image forming apparatus such as a copying machine, a facsimile machine, a printer, and a multifunction machine to charge the surface of a photoreceptor.

  In the corona discharger disclosed in Patent Document 1, a cylindrical grid electrode is rotatably provided in a state of surrounding the discharge wire. The grid electrode is surrounded by a shield case on the outer periphery excluding the portion facing the photoconductor. Such a grid electrode is rotated around the axis of the discharge wire to change the surface facing the photoreceptor. This prevents floating toner from concentrating and adhering to a specific portion of the grid electrode. In addition, an L-shaped toner receiving portion extends on one of the open ends of the shield case, and a pad-shaped cleaning member is provided above the toner receiving portion. The cleaning member scrapes off the toner adhering to the grid electrode to the toner receiving portion as the grid electrode rotates.

JP-A-6-194930

  However, in Patent Document 1, since the cleaning member is provided so as to extend in the longitudinal direction of the grid electrode, it is difficult to uniformly contact the entire longitudinal direction. Therefore, the cleaning member described above causes unevenness in cleaning. In addition, the cleaning of the inner surface side of the grid electrode is not taken into consideration, and there is a possibility that the charging performance may be deteriorated by the foreign matter attached to the inner peripheral surface.

  Therefore, a main object of the present invention is to provide a novel charging device and image forming apparatus.

  Another object of the present invention is to provide a charging device and an image forming apparatus that can properly clean a grid electrode and maintain charging performance for a long time.

  A first invention is a charging device for charging the surface of a photoconductor, which is formed in an endless belt shape, is suspended by a plurality of rollers, and is provided so as to be able to circulate along the longitudinal direction of the photoconductor Electrode, a discharge member disposed inside the grid electrode and extending in the longitudinal direction of the photosensitive member, and a foreign substance attached to the grid electrode along with the circumferential movement of the grid electrode on at least one of the inner peripheral surface or outer peripheral surface of the grid electrode A cleaning member for removing

  In the first invention, the charging device includes a grid electrode, a discharge member, and a cleaning member. The grid electrode is formed in an endless belt shape, and is suspended by a plurality of rollers so as to be able to move around along the longitudinal direction of the photoreceptor. The discharge member extends in the longitudinal direction of the photoconductor and is disposed inside the grid electrode. The cleaning member is provided on at least one of the inner peripheral surface or the outer peripheral surface of the grid electrode. When the grid electrode is moved around by the plurality of rollers, the foreign matters attached to the grid electrode are removed by the cleaning member.

  According to the first aspect, since the foreign matter attached to the grid electrode is removed by the cleaning member, the grid electrode can be appropriately cleaned, and the charging performance can be maintained for a long time.

  A second invention is dependent on the first invention, and the cleaning member includes a first cleaning member that contacts the inner peripheral surface of the grid electrode and a second cleaning member that contacts the outer peripheral surface of the grid electrode.

  In the second invention, the first cleaning member is provided at a position in contact with the inner peripheral surface of the grid electrode. The second cleaning member is provided at a position where the second cleaning member comes into contact with the outer peripheral surface of the grid electrode.

  According to the second invention, since the cleaning member is provided on the inner peripheral surface and the outer peripheral surface of the grid electrode, both surfaces of the grid electrode can be cleaned.

  A third invention is dependent on the first or second invention, and the cleaning member is provided in a portion opposite to a portion where the grid electrode and the photosensitive member face each other.

  In the third invention, the cleaning member is provided in a portion opposite to the portion where the grid electrode and the photoconductor face each other, that is, in a portion away from the photoconductor.

  According to the third aspect of the invention, since the foreign matter removed by the cleaning member is prevented from falling on the photoconductor, the photoconductor can be appropriately charged.

  A fourth invention is dependent on the third invention, and the cleaning member is provided by being shifted in the circumferential movement direction of the grid electrode.

  In the fourth invention, for example, the first cleaning member is provided on the upstream side of the second cleaning member in a position in contact with the inner peripheral surface of the grid electrode and in the circumferential movement direction of the grid electrode.

  According to the fourth invention, similarly to the first invention, the grid electrode can be appropriately cleaned, and the charging performance can be maintained for a long time.

  A fifth invention is dependent on the third invention, and the cleaning member is provided at a position facing each other across the grid electrode.

  In the fifth invention, the cleaning member is provided at a position facing each other across the grid electrode. For example, when the grid electrode is formed in a mesh shape, the foreign matter pushed out to the outer peripheral side of the grid electrode by the first cleaning member is removed by the second cleaning member.

  According to the fifth invention, for example, when the grid electrode is formed in a mesh shape, the foreign matter pushed out to the outer peripheral side of the grid electrode by the first cleaning member is removed by the second cleaning member. The grid electrode can be cleaned.

  A sixth invention is dependent on any one of the first to fifth inventions, the cleaning member is formed in a roller shape, and holding members that rotatably hold both ends of the rotation shaft of the cleaning member, and a holding member; A buffer member for suppressing rotation of the cleaning member is further provided between one end of the cleaning member.

  In the sixth invention, the cleaning member is formed in a roller shape. Moreover, the both ends of the rotating shaft of the cleaning member are rotatably held by a holding member having a groove portion recessed in a concave shape. Furthermore, a buffer member is provided between the holding member and one end of the cleaning member. When the grid electrode is moved around by the rotating roller, the cleaning member rotates. However, at this time, the rotation of the cleaning member is suppressed by friction generated between the cleaning member and the buffer member. That is, the cleaning member rotates little by little.

  According to the sixth aspect of the invention, the cleaning member rotates little by little by the circumferential movement of the grid electrode, so that the surface in contact with the grid electrode can be changed. That is, since the foreign matter is removed using not only one place but the entire outer peripheral surface of the cleaning member, the grid electrode can be cleaned more efficiently.

  A seventh invention is dependent on any one of the first to sixth inventions, wherein the plurality of rollers include a drive roller, and each of the end portions in the rotation axis direction of the drive roller is arranged radially in the circumferential direction. A plurality of protruding protrusions are provided, and each of the end portions in the width direction of the grid electrode is provided with a plurality of holes arranged in the circumferential movement direction of the grid electrode and engaged with the protrusions.

  In the seventh aspect of the present invention, a plurality of protrusions that protrude radially are arranged in the circumferential direction at each of the end portions in the rotation axis direction of the drive roller. Each of the end portions in the width direction of the grid electrode is provided with a plurality of holes that are arranged in the circumferential movement direction of the grid electrode and engage with the protrusions. As the drive roller rotates, the projections provided on the drive roller engage with the holes in the grid electrode, and the grid electrode is moved around.

  According to the seventh aspect, since the projection provided on the drive roller and the hole of the grid electrode engage with each other, the grid electrode can be moved more appropriately.

  An eighth invention is dependent on any one of the first to seventh inventions, and further includes an adjustment roller that presses against an inner peripheral surface of the grid electrode and adjusts the tension of the grid electrode.

  According to the eighth aspect, since the tension of the grid electrode is adjusted to be constant, the photosensitive member can be charged more stably.

  A ninth invention is dependent on any one of the first to eighth inventions, and further includes a housing member that houses the foreign matter removed by the cleaning member.

  In the ninth invention, the housing member is disposed such that the longitudinal direction thereof coincides with the longitudinal direction of the photosensitive member, and foreign matter removed by the cleaning member is accommodated.

  According to the ninth aspect, the foreign matter removed by the cleaning member can be prevented from scattering into the apparatus.

  A tenth aspect of the invention is an image forming apparatus including the charging device according to any one of the first to ninth aspects.

  According to the tenth invention, similarly to the first invention, the grid electrode can be appropriately cleaned, and the charging performance can be maintained for a long time.

  According to the present invention, the grid electrode can be appropriately cleaned, and the charging performance can be maintained for a long time.

  The above object, other objects, features, and advantages of the present invention will become more apparent from the following detailed description of embodiments with reference to the drawings.

FIG. 1 is a schematic configuration diagram of the entire image forming apparatus according to the first embodiment viewed from the front. FIG. 2 is an illustrative view showing the photoreceptor and the charger shown in FIG. 1 as viewed from the front. FIG. 3 is an illustrative view showing the photosensitive member and the charger shown in FIG. FIG. 4 is an illustrative view of the driving roller shown in FIG. FIG. 5 is an illustrative view for explaining the surface of the grid electrode. FIG. 6 is an illustrative view showing another example of the charger in the first embodiment. FIG. 7 is an illustrative view showing the photoconductor and the charger in the second embodiment as seen from the direction indicated by the arrow A shown in FIG. FIG. 8 is an illustrative view showing the photoconductor and the charger in the third embodiment as seen from the direction indicated by the arrow A shown in FIG. FIG. 9 is an illustrative view showing the first cleaning member shown in FIG. 8 as viewed from the longitudinal direction of the photosensitive member.

<First embodiment>
FIG. 1 is a schematic configuration diagram of an entire image forming apparatus 10 according to an embodiment of the present invention as viewed from the front.

  Referring to FIG. 1, an image forming apparatus 10 according to the first embodiment is a color printer, and forms a multicolor or single color image on a sheet (recording medium) by an electrophotographic method. However, the image forming apparatus 10 may be a monochrome printer. The image forming apparatus 10 need not be limited to a printer, and may be a copier, a facsimile machine, or a multifunction machine having these functions.

  First, the basic configuration of the image forming apparatus 10 will be schematically described. As shown in FIG. 1, the image forming apparatus 10 includes components such as a photoreceptor 12, a developing device 14, a charger 16, an exposure device 18, an intermediate transfer belt unit 20, a secondary transfer roller 22, and a fixing unit 24. An image is formed on the paper conveyed from the paper feed tray 26, and the image-formed paper is discharged to the paper discharge tray 28. As image data for forming an image on paper, image data input from an external computer is used. However, when the image forming apparatus 10 has a scanner function, not only image data input from the outside but also image data read from a document by a scanner can be used.

  Each of the components described above is accommodated in the housing 10a of the image forming apparatus 10. In addition, a control unit including a CPU and a memory (not shown) is provided in the housing 10a of the image forming apparatus 10. The control unit transmits a control signal to each part of the image forming apparatus 10 to cause the image forming apparatus 10 to execute various operations.

  Here, the image data handled in the image forming apparatus 10 corresponds to four color images of black (BK), magenta (M), cyan (C), and yellow (Y). For this reason, each of the photoconductor 12, the developing device 14, and the charger 16 is provided in four so as to form four types of latent images corresponding to the respective colors, and these constitute four image stations. The four image stations are arranged in a line along the traveling direction (circumferential movement direction) of the surface of the intermediate transfer belt 34, and from the downstream side in the traveling direction of the intermediate transfer belt 34, that is, to the secondary transfer roller 22. From the near side, black, magenta, cyan and yellow are arranged in this order. However, the arrangement order of the colors can be changed as appropriate.

  In each image station, the charger 16, the developing device 14, and the cleaning unit (not shown) are arranged in this order around the rotation direction of the photoconductor 12 (counterclockwise in FIG. 1). The developing device 14 is arranged so that the rotation shaft of the developing roller is aligned in parallel with the rotation shaft of the photoconductor 12. The charger 16 is arranged so that its own rotation axis is aligned in parallel with the rotation axis of the photoconductor 12. However, in FIG. 1, the rotation axis direction of the photoconductor 12 is the depth direction (front-rear direction) when the image forming apparatus 10 is viewed from the front.

  The photoconductor 12 is an image carrier in which a photosensitive layer (photoconductive layer) is formed on the surface of a conductive substrate, and is supported so as to be rotatable around an axis by a drive unit (not shown).

  The developing device 14 visualizes the electrostatic latent image formed on the surface of the photoreceptor 12 with toner (forms a toner image). A toner cartridge 30 is connected to the developing device 14 via a toner supply pipe 32.

  The charger 16 is a device that charges the surface of the photoreceptor 12 to a predetermined polarity and potential. As the charger 16, a brush-type charging device, a roller-type charging device, a corona discharge device, an ion generator, or the like can be used. The details of the charger 16 will be described later.

  The exposure device 18 is provided below the developing device 14. The exposure device 18 is configured as a laser scanning unit (LSU) provided with a laser emitting portion, a reflection mirror, and the like, and exposes the surface of the charged photoreceptor 12 to expose an electrostatic latent image corresponding to image data. Formed on the surface of the body 12.

  The intermediate transfer belt unit 20 includes an intermediate transfer belt 34, a driving roller 36, a driven roller 38, four intermediate transfer rollers (primary transfer rollers) 40, and the like, and is disposed above the photoreceptor 12.

  The intermediate transfer belt 34 is stretched by a plurality of rollers such as a driving roller 36 and a driven roller 38, and the surface (outer peripheral surface) thereof is disposed so as to come into contact with the surface of the photoreceptor 12. The intermediate transfer belt 34 rotates (circulates) in a predetermined direction (clockwise in FIG. 1) as the driving roller 36 rotates.

  The drive roller 36 is provided so as to be rotatable around its axis by a drive unit (not shown). The driven roller 38 rotates as the intermediate transfer belt 34 rotates and applies a certain tension to the intermediate transfer belt 34 to prevent the intermediate transfer belt 34 from loosening.

  The intermediate transfer roller 40 is disposed at a position facing each of the photoconductors 12 with the intermediate transfer belt 34 interposed therebetween. The intermediate transfer roller 40 is in pressure contact with the inner peripheral surface of the intermediate transfer belt 34 and rotates as the intermediate transfer belt 34 rotates. . Although not shown, the intermediate transfer roller 40 is connected to a transfer power source for applying a transfer bias. At the time of image formation, a voltage having a polarity opposite to the charging polarity of the toner constituting the toner image formed on the surface of the photoreceptor 12 is applied to the intermediate transfer roller 40. As a result, a transfer electric field is formed between the photoconductor 12 and the intermediate transfer belt 34, and the toner image formed on the photoconductor 12 is transferred to the outer peripheral surface of the intermediate transfer belt 34 by the action of the transfer electric field. For example, when forming a color image, each color toner image formed on each photoconductor 12 is sequentially transferred onto the intermediate transfer belt 34 (primary transfer) and transferred onto the outer peripheral surface of the intermediate transfer belt 34. A color toner image is formed. The toner remaining on the surface of the photoreceptor 12 after the toner image is transferred to the intermediate transfer belt 34 is removed and collected by the cleaning unit.

  In addition, the secondary transfer roller 22 is disposed at a position facing the drive roller 36 with the intermediate transfer belt 34 interposed therebetween. A transfer power supply (not shown) is connected to the secondary transfer roller 22, and a voltage (secondary transfer voltage) is applied to the secondary transfer roller 22 by the transfer power supply during image formation. The intermediate transfer belt is moved while the sheet passes through the transfer nip region between the intermediate transfer belt 34 and the secondary transfer roller 22 by the action of the transfer electric field formed by the secondary transfer roller 22 to which a voltage is applied. The toner image formed on the outer peripheral surface 34 is transferred (secondarily transferred) to the paper. Thereafter, the toner remaining on the surface of the intermediate transfer belt 34 is removed and collected by a transfer belt cleaning unit (not shown).

  The fixing unit 24 includes a heat roller and a pressure roller, and is disposed above the secondary transfer roller 22. The heat roller is set to have a predetermined fixing temperature, and when the paper passes through the fixing nip area between the heat roller and the pressure roller, the toner image transferred to the paper is melted, mixed, and mixed. The toner image is heat-fixed on the sheet by pressure contact.

  In addition, a paper conveyance path for sending the paper placed on the paper feed tray 26 to the paper discharge tray 28 via the secondary transfer roller 22 and the fixing unit 24 is provided in the housing 10 a of the image forming apparatus 10. It is formed. In the paper conveyance path, paper conveyance means such as conveyance rollers 42, 44, 46 and a registration roller 48 are appropriately arranged.

  At the time of image formation, the sheets placed on the sheet feeding tray 26 are guided to the sheet conveying path one by one by a pickup roller (not shown) and conveyed to the registration roller 48 by the conveying roller 42. The registration roller 48 conveys the sheet to the secondary transfer roller 22 at a timing when the leading end of the sheet and the leading end of the toner image on the intermediate transfer belt 34 are aligned, and the toner image is transferred onto the sheet. Thereafter, when the toner passes through the fixing unit 24, the unfixed toner on the paper is melted and fixed by heat, and the paper is discharged onto the paper discharge tray 28 through the transport rollers 44 and 46.

  In such an image forming apparatus 10, the charger 16 is an apparatus for uniformly charging the surface of the photoconductor 12, and includes a grid electrode 100 and a discharge wire 50 (see FIG. 2). The grid electrode 100 is provided between the discharge wire 50 and the photoconductor 12 and uniformly charges the photoconductor 12 by controlling the current flowing from the discharge wire 50 to the photoconductor 12.

  However, if foreign matter (toner, external additive, discharge product, etc.) adheres to the grid electrode 100, the discharge from the discharge wire 50 to the photoconductor 12 becomes unstable, and charging unevenness occurs in the photoconductor 12. There is a problem.

  As an example of a method for solving this problem, as shown in the background art, as a cylindrical grid electrode rotates, a method of cleaning by scraping toner adhering to the grid electrode to a toner receiving portion with a cleaning member There is.

  However, in the background art method, since the cleaning member is provided so as to extend in the longitudinal direction of the grid electrode, it is difficult to uniformly contact the entire longitudinal direction, resulting in uneven cleaning. Further, since the cleaning of the inner surface side of the grid electrode is not taken into consideration, there is a possibility that the charging performance is deteriorated by the foreign matter attached to the inner peripheral surface.

  In order to avoid such inconvenience, in the first embodiment, the grid electrode can be appropriately cleaned, and the charging performance can be maintained for a long time. This will be specifically described below.

  FIG. 2 is an illustrative view showing the photoreceptor 12 and the charger 16 shown in FIG. 1 as viewed from the front. 3 is an illustrative view of the photoconductor 12 and the charger 16 shown in FIG. 4 is an illustrative view of the drive roller 56 shown in FIG. Furthermore, FIG. 5 is an illustrative view for explaining the surface of the grid electrode 100. FIG. 6 is an illustrative view showing another example of the charger 16 in the first embodiment.

  As shown in FIG. 2, the charger 16 includes a discharge wire 50, a wire case 52, and a grid electrode 100, and is disposed on the upper left portion of the photoreceptor 12 in FIG. 2. The discharge wire 50 is disposed such that its longitudinal direction coincides with the longitudinal direction (axial direction) of the photoreceptor 12. The discharge wire 50 is applied with a high voltage by a voltage application circuit (not shown), and generates a corona discharge when the high voltage is applied. Then, ions generated by corona discharge flow as a discharge current to the photosensitive member 12 side, thereby charging the surface of the photosensitive member 12. As the discharge wire 50, for example, stainless steel, nickel, molybdenum, tungsten or the like is used. However, in the first embodiment, the discharge wire 50 is used. However, the present invention is not limited to this. For example, instead of the discharge wire 50, a sawtooth thin plate electrode may be used.

  The wire case 52 is a case for accommodating the discharge wire 50 and is formed in a hollow rectangular parallelepiped shape. The wire case 52 is arranged so that its longitudinal direction is parallel to the longitudinal direction of the photoconductor 12, and an opening is formed on the surface facing the photoconductor 12. That is, the wire case 52 is disposed such that its longitudinal direction coincides with the longitudinal direction of the discharge wire 50.

  The grid electrode 100 is formed in an endless belt shape and is disposed so as to cover the outer periphery of the wire case 52. Further, the grid electrode 100 has a portion facing the photoconductor 12 and a portion not facing the photoconductor 12 (hereinafter referred to as “opposite portion”).

  Further, although omitted in FIG. 1, a toner receiving tray 54 is disposed below the charger 16 in FIG. Further, the toner receiving tray 54 is formed in a hollow rectangular parallelepiped shape, and is arranged so that the longitudinal direction thereof coincides with the longitudinal direction of the photoreceptor 12. The toner receiving tray 54 accommodates foreign matters removed by a first cleaning member 64a and a second cleaning member 64b described later.

  Further, as shown in FIG. 3, a driving roller 56 and a driven roller 58 are disposed inside the grid electrode 100. As can be seen from FIG. 3, the grid electrode 100 is suspended by a driving roller 56 and a driven roller 58. In FIG. 3, in order to show the discharge wire 50, the wire case 52 is shown in a sectional view.

  Further, as shown in FIG. 4, the drive roller 56 includes a rotating shaft 60 and a sprocket 62. The sprocket 62 is formed in a disc shape, and is provided at each end of the rotating shaft 60 with a gap d. In addition, a plurality of protrusions are formed on the outer periphery of the sprocket 62 so as to protrude radially in the circumferential direction.

  As shown in FIG. 5, a plurality of holes 102 are formed in each of the end portions in the width direction of the grid electrode 100 side by side in the circumferential movement direction of the grid electrode 100 with a distance d. The hole 102 is formed to engage with a protrusion provided on the sprocket 62. Further, the portion excluding each of the end portions in the width direction of the grid electrode 100 is formed in a mesh shape.

  Returning to FIG. 3, the first cleaning member 64 a and the second cleaning member 64 b are disposed in a direction opposite to the opening of the wire case 52, that is, in a portion opposite to the grid electrode 100. The first cleaning member 64 a is provided at a position that contacts the inner peripheral surface of the grid electrode 100. In addition, the second cleaning member 64 b is provided on the downstream side of the first cleaning member 64 a in a position in contact with the outer peripheral surface of the grid electrode 100 and in the circumferential movement direction of the grid electrode 100. As the first cleaning member 64a and the second cleaning member 64b, for example, a cleaning pad made of felt of fluororesin fiber is used.

  Further, a tension roller 120 is provided at a position opposite to the opening of the wire case 52 and in contact with the inner peripheral surface of the grid electrode 100. The tension roller 120 is supported by a mechanism (not shown) so as to be movable up and down, and is adjusted so that the tension of the grid electrode 100 becomes constant by being pressed against the inner peripheral surface of the grid electrode 100.

  In the charger 16 having such a configuration, for example, when the rotating shaft 60 rotates counterclockwise by a driving unit (not shown), the sprocket 62 also rotates. Further, since the projections of the sprocket 62 and the holes 102 provided in the grid electrode 100 are engaged, the grid electrode 100 moves in a counterclockwise direction as the sprocket 62 rotates. Due to this circular movement, the foreign matter adhering to the grid electrode 100 is removed by the first cleaning member 64a and the second cleaning member 64b that are in contact with the inner and outer peripheral surfaces of the grid electrode 100. The foreign matter removed by the first cleaning member 64 a and the second cleaning member 64 b is accommodated in the toner receiving tray 54.

  According to the first embodiment, since the grid electrode 100 is moved around, foreign substances attached to the inner and outer peripheral surfaces of the grid electrode 100 are removed by the first cleaning member 64a and the second cleaning member 64b. The grid electrode 100 can be appropriately cleaned, and the charging performance can be maintained for a long time.

  In addition, according to the first embodiment, the first cleaning member 64a and the second cleaning member 64b are provided in the opposite portion of the grid electrode 100, so that the foreign matter removed by the first cleaning member 64a and the second cleaning member 64b is removed. It can prevent falling on the photoreceptor 12.

  Furthermore, according to the first embodiment, since it is not necessary to increase the distance between the grid electrode 100 and the photoconductor 12, it is possible to discharge to the photoconductor 12 at an appropriate interval. That is, it is possible to reduce the size of the apparatus and to charge the photoreceptor 12 stably.

  Furthermore, according to the first embodiment, since the tension of the grid electrode 100 is adjusted to be constant by the tension roller 120, the surface of the grid electrode 100 facing the photoconductor 12 is in the longitudinal direction of the photoconductor 12. And maintained in parallel. Therefore, the charging of the photoconductor 12 by the discharge wire 50 can be stabilized.

  In the first embodiment, the charger 16 is disposed at the upper left portion in FIG. 2, but the present invention is not limited to this. For example, the charger 16 may be disposed below the photoreceptor 12 in FIG. In such a case, the toner receiving tray 54 is disposed below the charger 16. However, if the charger 16 is disposed above the photoreceptor 12 in FIG. 2, the toner receiving tray 54 cannot be disposed, and the removed foreign matter may fall on the photoreceptor 12. Therefore, the charger 16 is preferably arranged at a position other than above the photoconductor 12 in FIG.

  In the first embodiment, the grid electrode 100 is moved around in accordance with the rotation of the sprocket 62. However, the present invention is not limited to this. For example, as shown in FIG. 6, rotating rollers 130a, 130b, 130c, and 130d are provided at positions that come into contact with the four corners inside the grid electrode 100, and these are rotated so that the grid electrode 100 is moved around. You may do it.

  Further, the driving roller 56 may be provided at a position facing the rotating rollers 130a and 130b in FIG. 6 and a position contacting the outer peripheral surface of the grid electrode 100. Furthermore, the driving roller 56 may be provided at a position facing the rotating rollers 130 c and 130 d in FIG. 6 and a position contacting the outer peripheral surface of the grid electrode 100. In this case, since the sprocket 62 is engaged with the hole 102 provided in the grid electrode 100 by the rotational drive of the drive roller 56, the grid electrode 100 is moved around.

  Furthermore, in the first embodiment, the protrusion provided on the outer periphery of the sprocket 62 is used to engage with the hole 102 provided in the grid electrode 100, but the present invention is not limited to this. For example, instead of the sprocket 62, a protrusion may be provided on the outer periphery of the rotating shaft 60, and the protrusion may be used to engage with the hole 102 provided in the grid electrode 100.

In the first embodiment, one first cleaning member 64a is provided on the inner peripheral surface of the grid electrode 100 and one second cleaning member 64b is provided on the outer peripheral surface of the grid electrode 100. However, the present invention is not limited to this. There is no need to For example, a plurality of first cleaning members 64 a or second cleaning members 64 b may be provided on the inner peripheral surface or outer peripheral surface of the grid electrode 100. In such a case, the foreign matter adhering to the grid electrode 100 can be more reliably removed. However, the first cleaning member 64a and the second cleaning member 64b are preferably provided on the side opposite to the opening of the wire case 52, as in the first embodiment.
<Second embodiment>
The charger 16 of the second embodiment is the same as that of the first embodiment except that the arrangement positions of the first cleaning member 64a and the second cleaning member 64b are changed.

  FIG. 7 is an illustrative view of the photoconductor 12 and the charger 16 in the second embodiment when viewed from the direction indicated by the arrow A shown in FIG.

  As described in the first embodiment, the portion excluding each of the end portions in the width direction of the grid electrode 100 is formed in a mesh shape. Therefore, for example, when the grid electrode 100 is moved around, the foreign matter attached to the grid electrode 100 may be pushed out to the outer peripheral side of the grid electrode 100 by the first cleaning member 64a.

  Therefore, in the second embodiment, as shown in FIG. 7, the first cleaning member 64a and the second cleaning member 64b are provided at positions facing each other with the grid electrode 100 interposed therebetween. Thereby, the foreign material pushed out to the outer peripheral side of the grid electrode 100 by the first cleaning member 64a is removed by the second cleaning member 64b. Further, the foreign matter pushed out to the inner peripheral side of the grid electrode 100 by the second cleaning member 64b is removed by the first cleaning member 64a.

According to the second embodiment, since the first cleaning member 64a and the second cleaning member 64b are provided at positions facing each other across the grid electrode 100, the first cleaning member 64a or the second cleaning member 64b causes the grid to The foreign matter pushed out to the outer peripheral side or inner peripheral side of the electrode 100 can be removed by the first cleaning member 64a or the second cleaning member 64b. Therefore, the foreign matter adhering to the grid electrode 100 can be reliably removed.
<Third embodiment>
The charger 16 of the third embodiment is the same as that of the first embodiment except that the shapes of the first cleaning member 64a and the second cleaning member 64b are changed.

  FIG. 8 is an illustrative view of the photoconductor 12 and the charger 16 in the third embodiment as seen from the direction indicated by the arrow A shown in FIG. FIG. 9 is an illustrative view showing the first cleaning member 64a shown in FIG. 8 from the longitudinal direction of the photosensitive member.

  As shown in FIG. 8, the first cleaning member 64a and the second cleaning member 64b are formed in a roller shape. Moreover, as shown in FIG. 9, both ends of the rotating shaft 66 of the first cleaning member 64a are rotatably held by a holding member 66 having a groove that is recessed in a concave shape. Further, a buffer member 70 is provided between one end of the first cleaning member 64 a and the holding member 68. The second cleaning member 64b has the same configuration.

  For example, when the grid electrode 100 is moved around, the first cleaning member 64a and the second cleaning member 64b rotate due to friction generated between the grid electrode 100 and the grid electrode 100. However, the first cleaning member 64a and the second cleaning member 64b rotate only slightly because the rotation is suppressed by the friction generated between the first cleaning member 64a and the second cleaning member 64b. By this rotation, the surfaces of the first cleaning member 64a and the second cleaning member 64b that contact the grid electrode 100 change.

  According to the third embodiment, since the first cleaning member 64a and the second cleaning member 64b are formed in a roller shape, when the grid electrode 100 is moved around, the surface that contacts the grid electrode 100 is changed. Can do. That is, the foreign matter can be removed using not only one place but the entire outer peripheral surfaces of the first cleaning member 64a and the second cleaning member 64b. Therefore, the grid electrode 100 can be cleaned more efficiently.

DESCRIPTION OF SYMBOLS 10 ... Image forming apparatus 12 ... Photoconductor 14 ... Developing device 16 ... Charger 18 ... Exposure device 20 ... Intermediate transfer unit 22 ... Secondary transfer roller 34 ... Intermediate transfer belt 56 ... Drive roller 58 ... Follower roller 62 ... Sprocket 64a ... 1st cleaning member 64b ... 2nd cleaning member 66 ... Rotating shaft 68 ... Holding member 70 ... Buffer member 100 ... Grid electrode 102 ... Hole 120 ... Tension roller

Claims (10)

A charging device for charging the surface of a photoreceptor,
A grid electrode formed in an endless belt shape, suspended by a plurality of rollers, and provided so as to be able to move around along the longitudinal direction of the photoreceptor;
A discharge member disposed inside the grid electrode and extending in the longitudinal direction of the photoreceptor, and at least one of an inner peripheral surface or an outer peripheral surface of the grid electrode is attached to the grid electrode as the grid electrode rotates. A charging device comprising a cleaning member that removes foreign matter.   The charging device according to claim 1, wherein the cleaning member includes a first cleaning member that contacts an inner peripheral surface of the grid electrode and a second cleaning member that contacts an outer peripheral surface of the grid electrode.   The charging device according to claim 1, wherein the cleaning member is provided in a portion opposite to a portion where the grid electrode and the photoconductor face each other.   The charging device according to claim 3, wherein the cleaning member is provided while being shifted in a circumferential movement direction of the grid electrode.   The charging device according to claim 3, wherein the cleaning members are provided at positions facing each other across the grid electrode. The cleaning member is formed in a roller shape,
The holding member which hold | maintains both ends of the rotating shaft of the said cleaning member rotatably, The buffer member which suppresses rotation of the said cleaning member between the said holding member and one end of the said cleaning member is further provided. The charging device according to any one of 1 to 5. The plurality of rollers include drive rollers,
Each of the end portions in the rotation axis direction of the drive roller is provided with a plurality of protrusions protruding radially in the circumferential direction,
7. The charging device according to claim 1, wherein each of the end portions in the width direction of the grid electrode is provided with a plurality of holes arranged in the circumferential movement direction of the grid electrode and engaged with the protrusions. .   8. The charging device according to claim 1, further comprising an adjustment roller that is in pressure contact with an inner peripheral surface of the grid electrode and adjusts tension of the grid electrode.   The charging device according to claim 1, further comprising a storage member that stores the foreign matter removed by the cleaning member.   An image forming apparatus comprising the charging device according to claim 1.

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