JP5921896B2 - Charging device and image forming apparatus - Google Patents

Description

  The present invention relates to a charging device including a non-contact type discharge electrode and an image forming apparatus including the charging device.

  2. Description of the Related Art Conventionally, in an image forming apparatus that forms an image by an electrophotographic method, there is an apparatus that charges a photosensitive member by a charging device in which a non-contact type discharge electrode is fixed in a case having an opening. The charging device causes the photoconductor to corona discharge from the tip of the discharge electrode to which a high voltage is applied, and charges the photoconductor.

  In the charging device, air flows from the opening of the case and circulates in the case by the ionic wind generated during discharge. At this time, when dust flows from the outside of the case, the dust adheres to the discharge electrode. There will be no problem if dust adheres to the tip of the discharge electrode, but if dust adheres to the tip of the discharge electrode, it will not be able to discharge uniformly, causing uneven discharge, and the surface of the photoreceptor cannot be charged uniformly. .

  For this reason, in the conventional charging device provided with the discharge electrode, in order to ensure the flow velocity of the airflow flowing from the intake port and guide it to the tip of the discharge electrode, without passing through the case with a wide opening width, There is a device that passes through the inside of a guide member whose facing interval is narrower than that of the air inlet, prevents dust from adhering to the tip of the discharge electrode, and discloses improvement in image quality deterioration due to discharge unevenness (for example, Patent Document 1). reference.).

JP 2011-069973 A

  However, the charging device disclosed in Patent Document 1 cannot completely prevent dust from adhering to the tip of the discharge electrode.

  Further, along with recent demands for downsizing and weight reduction of image forming apparatuses, charging apparatuses are also required to be downsized. However, a cleaning mechanism that protects the tip of the discharge electrode with air and a tip of the discharge electrode are provided. It was difficult to place two of the cleaning mechanisms that clean directly in a limited space.

  Therefore, in view of the above problems, an object of the present invention is to arrange two cleaning mechanisms for protecting the tip end portion of the discharge electrode with air and a cleaning mechanism for directly cleaning the tip end portion of the discharge electrode in a limited space. It is an object of the present invention to provide a charging device that can be used.

  The charging device of the present invention includes a case, a discharge electrode, a first holding member, a blower, a cleaning member, and a second holding member.

  The case has an opening. The discharge electrode is disposed in the case, and a plurality of tip portions are formed. At least a portion of the first holding member is disposed in the case and holds the discharge electrode. The blower sends air into the case from the opening of the case. The cleaning member is disposed in the case and cleans the tip of the discharge electrode. At least a part of the second holding member is disposed in the case and holds the cleaning member.

  Further, the first holding member forms a flow path through which the air sent from the blower passes through the tip of the discharge electrode. The second holding member is configured to come into contact with both side surfaces of the case and the first holding member and to be movable along the longitudinal direction of the discharge electrode.

  In this configuration, air sent from the blower into the case passes through the tip of the discharge electrode, and the cleaning member is movable in the longitudinal direction of the discharge electrode. Therefore, dust can be prevented from adhering to the tip of the discharge electrode by the air, and dust attached to the tip of the discharge electrode can be removed by the cleaning member. Thus, the cleaning effect with respect to the front-end | tip part of a discharge electrode improves by combining the flow of air and the cleaning member.

  Further, the second holding member comes into contact with a total of three positions of the side surfaces of the case and the first holding member. As a result, since the second holding member is configured to be stably movable along the longitudinal direction of the discharge electrode, the cleaning member held by the second holding member stably contacts the tip of the discharge electrode. To do. Therefore, the dust adhering to the front-end | tip part of a discharge electrode can be removed efficiently.

  The charging device according to the present invention is a charging device that can arrange a cleaning mechanism that protects the tip end portion of the discharge electrode with air and a cleaning mechanism that directly cleans the tip end portion of the discharge electrode in a limited space. provide.

1 is a front view illustrating a configuration of an image forming apparatus according to a first embodiment of the present invention. 1 is a perspective view illustrating a configuration of a charging device according to a first embodiment of the present invention. It is sectional drawing which shows the structure of the charging device which concerns on 1st Embodiment of this invention. It is a perspective view which shows the structure of the drive shaft in a charging device. It is the figure which abbreviate | omitted the 2nd holding member from FIG. It is sectional drawing which shows the structure of the charging device which concerns on 2nd Embodiment of this invention.

  Hereinafter, a charging device according to an embodiment of the present invention will be described in detail with reference to the drawings.

  First, a first embodiment of the present invention will be described.

  FIG. 1 is a front view showing a configuration of an image forming apparatus 100 according to the first embodiment of the present invention.

  The image forming apparatus 100 forms a multi-color or single-color image on a predetermined sheet (recording paper) in accordance with image data transmitted from the outside. The image forming apparatus 100 includes a document processing device 120, a paper feeding unit 80, an image forming unit 110, and a paper discharge unit 90.

  The document processing device 120 includes a document placement table 121, a document transport device 122, and a document reading unit 123. The document placing table 121 is made of transparent glass and is configured to be able to place a document. The document transport device 122 transports the documents stacked on the document tray one by one. Further, the document conveying device 122 is configured to be rotatable in the direction of the arrow 124, and the document can be placed on the document placing table 121 by opening the document placing table 121. The document reading unit 123 reads a document being transported by the document transport device 122 or a document placed on the document placing table 121.

  The paper feed unit 80 is provided with a paper feed cassette 81, a manual paper feed cassette 82, a pickup roller 83, and a pickup roller 84. The paper feed cassette 81 is a tray for storing regular sheets. The manual paper feed cassette 82 is a tray on which an irregular sheet can be placed. The pickup roller 83 is provided near the end of the paper feed cassette 81, picks up sheets one by one from the paper feed cassette 81, and supplies them to the paper transport path 101. Similarly, the pickup roller 84 is provided in the vicinity of the end of the manual paper feed cassette 82, picks up sheets one by one from the manual paper feed cassette 82, and supplies them to the paper transport path 101.

  The image forming unit 110 includes image forming stations 31, 32, 33, 34, an exposure unit 30, an intermediate transfer belt unit 50, and a fixing unit 70. Each of the image forming stations 31, 32, 33, and 34 is provided with a photosensitive drum 10, a charging device 20, a developing device 40, and a cleaner unit 60. Black (K), cyan (C), magenta (M), and magenta (M) are provided. This corresponds to a color image using each color of yellow (Y). In the present embodiment, the image forming station 31 will be described.

  The photoconductor drum 10 is rotated when an image is formed and carries a developer image. Around the photosensitive drum 10, the charging device 20, the exposure unit 30, the developing device 40, the intermediate transfer belt unit 50, and the cleaner unit 60 are arranged in this order from the upstream in the rotation direction. The fixing unit 70 is located on the most downstream side of the image forming unit 110 on the paper conveyance path 101.

  The charging device 20 is a charging unit for uniformly charging the surface of the photosensitive drum 10 to a predetermined potential. Details will be described in FIG. The exposure unit 30 has a function of forming an electrostatic latent image corresponding to the image data on the surface thereof by exposing the charged photosensitive drum 10 according to the input image data. The developing device 40 visualizes the electrostatic latent image formed on the photosensitive drum 10 with toner.

  The intermediate transfer belt unit 50 includes an intermediate transfer belt 51, an intermediate transfer belt drive roller 52, an intermediate transfer belt driven roller 53, an intermediate transfer roller 54, and an intermediate transfer belt cleaning unit 55.

  The intermediate transfer belt driving roller 52, the intermediate transfer belt driven roller 53, and the intermediate transfer roller 54 are driven to rotate while the intermediate transfer belt 51 is stretched. Further, the intermediate transfer roller 54 gives a transfer bias for transferring the toner image on the photosensitive drum 10 onto the intermediate transfer belt 51.

  The intermediate transfer belt 51 is provided in contact with the photosensitive drum 10. The toner image formed on the photosensitive drum 10 is transferred to the intermediate transfer belt 51, thereby forming a toner image on the intermediate transfer belt 51.

  Transfer of the toner image from the photosensitive drum 10 to the intermediate transfer belt 51 is performed by an intermediate transfer roller 54 that is in contact with the back side of the intermediate transfer belt 51. A high voltage transfer bias (a high voltage having a polarity (+) opposite to the toner charging polarity (−)) is applied to the intermediate transfer roller 54 in order to transfer the toner image.

  The electrostatic latent images visualized on the photosensitive drum 10 as described above are stacked on the intermediate transfer belt 51. The image information stacked in this way is transferred onto the sheet by the transfer roller 56 disposed at the contact position between the sheet and the intermediate transfer belt 51 as the intermediate transfer belt 51 rotates.

  At this time, the intermediate transfer belt 51 and the transfer roller 56 are pressed against each other at a predetermined nip, and a voltage for transferring the toner onto the paper is applied to the transfer roller 56 (the polarity opposite to the toner charging polarity (−)). (+) High voltage).

  Further, as described above, the toner adhered to the intermediate transfer belt 51 by contacting the photosensitive drum 10 or the toner remaining on the intermediate transfer belt 51 without being transferred onto the sheet by the transfer roller 56 is transferred to the intermediate transfer belt 51. It is set to be removed and collected by the cleaning unit 55.

  The cleaner unit 60 removes and collects toner remaining on the surface of the photosensitive drum 10 after development and image transfer. The fixing unit 70 includes a heating roller 71 and a pressure roller 72, and the heating roller 71 and the pressure roller 72 rotate with the sheet interposed therebetween. An external heating belt 73 for heating the heating roller 71 from the outside is provided.

  The paper discharge unit 90 includes a paper discharge tray 91 and a paper discharge roller 92. The sheet that has passed through the fixing unit 70 is discharged to a discharge tray 91 via a discharge roller 92. The paper discharge tray 91 is a tray for collecting printed sheets.

  When a double-sided printing request is made, when the single-sided printing is completed and the trailing edge of the sheet that has passed through the fixing unit 70 is gripped by the paper discharging roller 92 as described above, the paper discharging roller 92 rotates in the reverse direction. The sheet is guided to the conveyance rollers 102 and 103. Then, after printing is performed on the back side of the sheet through the registration roller 104, the sheet is discharged to the discharge tray 91.

  FIG. 2 is a perspective view showing the configuration of the charging device 20 according to the first embodiment of the present invention.

  In order to describe in detail the configuration of the charging device 20 in each embodiment of the present invention, the A-A ′ cross-sectional view of FIG. 2 is used. Hereinafter, in the case of a cross-sectional view, the A-A ′ cross-sectional view of FIG. 2 is shown.

  FIG. 3 is a cross-sectional view showing the configuration of the charging device 20 according to the first embodiment of the present invention.

  The charging device 20 is disposed to face the photosensitive drum 10. The charging device 20 includes a case 210, a discharge electrode 220, a holding member 230, a blower 240, a rubber roller 250, a carriage 260, and a drive shaft 270.

  The case 210 forms an outer wall of the charging device 20 and has an opening 212 on a surface opposite to the surface facing the photosensitive drum 10. Case 210 is made of SUS. The discharge electrode 220 is disposed in the case 210 and has a plurality of tip portions. The discharge electrode 220 is made of SUS. The charging device 20 charges the photosensitive drum 10 by corona discharging the photosensitive drum 10 from a plurality of tips of the discharge electrode 220 to which a high voltage is applied.

  The holding member 230 is a first holding member that is disposed at least partially in the case 210 and holds the discharge electrode 220. The holding member 230 is made of resin. The air blowing unit 240 sends air into the case 210 from the opening 212 of the case 210. In the present embodiment, the air blowing unit 240 is disposed so as to face the opening 212. However, as long as air is sent into the case 210 from the opening 212 of the case 210 (an air flow is generated in the case 210). Therefore, for example, a suction fan disposed at the outlet of the air may be used.

  The rubber roller 250 is a cleaning member that is disposed in the case 210 and cleans the tip of the discharge electrode 220. The rubber roller 250 adsorbs dust adhering to the tip of the discharge electrode 220 by contacting the tip of the discharge electrode 220. The carriage 260 is a second holding member that is disposed at least partially in the case 210 and holds the rubber roller 250. The carriage 260 is made of resin.

  The drive shaft 270 is disposed outside the case 210 and is fitted onto a part of the carriage 260. As shown in FIG. 4, the drive shaft 270 is formed with a spiral groove. Accordingly, the rotation of the drive shaft 270 causes the carriage 260 to move along the longitudinal direction of the drive shaft 270.

  In addition, the holding member 230 forms a flow path through which the air sent from the blower 240 passes through the tip of the discharge electrode 220. The carriage 260 is in contact with both side surfaces of the case 210 and the holding member 230 and is configured to be movable along the longitudinal direction of the discharge electrode 220.

  In this configuration, air sent from the blower 240 into the case 210 passes through the tip of the discharge electrode 220, and the rubber roller 250 is movable in the longitudinal direction of the discharge electrode 220. Accordingly, dust can be prevented from adhering to the tip of the discharge electrode 220 by the air, and dust attached to the tip of the discharge electrode 220 can be removed by the rubber roller 250. Thus, by combining the air flow and the rubber roller 250, the cleaning effect on the tip of the discharge electrode 220 is improved.

  Further, the carriage 260 is in contact with both side surfaces of the case 210 and the holding member 230 in total. As a result, since the carriage 260 is configured to be stably movable along the longitudinal direction of the discharge electrode 220, the rubber roller 250 held by the carriage 260 stably contacts the tip portion of the discharge electrode 220. Therefore, the dust adhering to the tip portion of the discharge electrode 220 can be efficiently removed.

  The carriage 260 is preferably engaged with the holding member 230 as indicated by reference numeral 262.

  In this configuration, the carriage 260 can be more stable when moving along the longitudinal direction of the discharge electrode 220, so that the rubber roller 250 comes into contact with the tip of the discharge electrode 220 more stably. Therefore, the dust adhering to the tip portion of the discharge electrode 220 can be efficiently removed.

  As indicated by reference numeral 232, the holding member 230 preferably has an uneven shape on the contact surface with the carriage 260.

  In this configuration, when the carriage 260 moves along the longitudinal direction of the discharge electrode 220, the contact area between the holding member 230 and the carriage 260 is reduced, and as a result, the mutual resistance is reduced. 260 can be moved.

  FIG. 5 is a view in which the carriage 260 is omitted from FIG.

  The holding member 230 is preferably composed of a pair of members, and the surfaces facing each other form an air flow path. Here, air flow paths are indicated by arrows.

  With this configuration, the existing member (holding member 230) can achieve a configuration that guides the air fed from the opening 212 of the case 210 to the tip of the discharge electrode 220. Therefore, it is possible to prevent dust from adhering to the tip of the discharge electrode 220 by the air sent by the blower 240 without increasing the number of parts.

  The distance between the opposing surfaces of the pair of holding members 230 is preferably configured to be narrower than the opening 212 of the case 210.

  In this configuration, the air sent from the opening 212 of the case 210 is accelerated when passing through the air flow path formed by the pair of holding members 230. Therefore, since high-speed air reaches the tip of the discharge electrode 220, it is possible to efficiently prevent dust from adhering to the tip of the discharge electrode 220.

  Next, a second embodiment of the present invention will be described. In the present embodiment, items described in the first embodiment are omitted.

  FIG. 6 is a cross-sectional view showing the configuration of the charging device 20 according to the second embodiment of the present invention.

  As indicated by reference numeral 266, the carriage 264 preferably has an uneven surface on the contact surface with the holding member 230.

  In this configuration, when the carriage 260 moves along the longitudinal direction of the discharge electrode 220, the contact area between the holding member 230 and the carriage 260 is reduced, and as a result, the mutual resistance is reduced. 260 can be moved.

  In addition, although 1st Embodiment and 2nd Embodiment were demonstrated so far, you may combine these.

  Finally, the description of the above-described embodiment is to be considered in all respects as illustrative and not restrictive. The scope of the present invention is shown not by the above embodiments but by the claims. Furthermore, the scope of the present invention is intended to include all modifications within the meaning and scope equivalent to the scope of the claims.

10-photosensitive drum 20-charging device 210-case 212-opening 220-discharge electrode 230-holding member 240-air blowing unit 250-rubber roller 260-carriage

Claims (7)

A case having an opening;
A discharge electrode disposed in the case and formed with a plurality of tips; and
A first holding member at least partially disposed in the case and holding the discharge electrode;
An air blowing section for sending air into the case from the opening of the case;
A cleaning member disposed in the case and cleaning the tip of the discharge electrode;
A second holding member that is at least partially disposed in the case and holds the cleaning member;
With
The first holding member forms a flow path for allowing the air sent from the blower to pass through the tip of the discharge electrode,
The second holding member is configured to be in contact with both side surfaces of the case and the first holding member, move along the longitudinal direction of the discharge electrode , and open on a surface facing the opening. Charging device. The charging device according to claim 1, wherein the second holding member is engaged with the first holding member. The charging device according to claim 1, wherein a contact surface of the first holding member with the second holding member has an uneven shape. The charging device according to claim 1, wherein a contact surface of the second holding member with the first holding member has an uneven shape. 5. The charging device according to claim 1, wherein the first holding member includes a pair of members, and surfaces facing each other form an air flow path. The charging device according to claim 5, wherein an interval between opposing surfaces of the pair of first holding members is configured to be narrower than an opening of the case. A photoreceptor,
The charging device according to any one of claims 1 to 6, which charges the surface of the photoreceptor.
An image forming apparatus comprising:

Images