JP4785718B2 - Cleaning device and image forming apparatus equipped with the same - Google Patents

Description

  The present invention relates to a cleaning device for transferring a toner image onto a sheet and then removing adhering matter such as toner remaining on the surface of an image carrier to perform cleaning. The present invention also relates to an electrophotographic image forming apparatus typified by a copying machine or a printer equipped with this cleaning device.

  In an electrophotographic image forming apparatus such as a copying machine or a printer, a photosensitive drum is widely used as an image carrier. A general image forming operation using the photosensitive drum is as follows. The surface of the photosensitive drum is uniformly charged with a predetermined potential by a charging device, and by irradiating the LED light or the like of the exposure device there, the potential is partially attenuated to form an electrostatic latent image of an original image. Is done. The electrostatic latent image is developed with a developing device, whereby a toner image is formed on the surface of the photosensitive drum. This toner image is transferred to the sheet when the sheet is inserted into a transfer region formed by bringing the photosensitive drum and the transfer member into contact with each other or close to each other.

  In such an image forming apparatus, after a toner image is transferred to a sheet, a small amount of toner may remain on the surface of the photosensitive drum without being transferred to the sheet. Residual toner and other adhering matter adhering to the surface of the photosensitive drum become an obstacle to the next new image formation, so that cleaning is necessary. As a cleaning method used for such a purpose, a cleaning roller, a polishing roller, a rotating brush, or the like, which is a rotating member, is pressed against the surface of the photosensitive drum to move and collect a deposit such as residual toner on the rotating member. A method, a method in which a blade is brought into contact with the surface of the photosensitive drum to scrape off an adhering matter, or a cleaning method in which these methods are combined is widely known.

An example of an image forming apparatus that cleans the surface of a photosensitive drum after transferring a toner image onto a sheet by using a polishing roller that is a rotating member and a cleaning blade as described above can be seen in Patent Document 1. .
JP 2000-276026 A (page 3, FIG. 3)

  In the image forming apparatus described in Patent Document 1, in a cleaning device for a photosensitive drum provided with a polishing roller and a cleaning blade, a scraper is brought into contact with the lower side of the polishing roller, so that the drum is disposed in the vicinity of the contact portion. The toner for polishing is retained to achieve suitable polishing. However, in this configuration, there is a possibility that adhered matter such as toner removed from the surface of the photosensitive drum stays in a form in which it cannot move around the contact portion. The toner stays for a long time due to friction with the polishing roller and the photosensitive drum, and becomes excessively charged, adversely affecting the photosensitive drum, and causing image defects such as minute black spots at the next image formation. Is a problem.

  The present invention has been made in view of the above points, and includes a cleaning roller that removes deposits on the surface of the image carrier, and a toner receiving member that is provided to adhere polishing toner to the surface of the cleaning roller. In the cleaning device, it is possible to prevent excessive charging of the toner stored in the toner receiving member, and it is possible to maintain suitable cleaning performance on the surface of the image carrier without adversely affecting the next charging. It is an object to provide a simple cleaning device. Another object of the present invention is to provide a high-performance image forming apparatus equipped with such a cleaning device.

  In order to solve the above-described problems, the present invention is arranged such that a cleaning roller that rotates in contact with an image bearing member and removes deposits on the surface of the image bearing member, and a clearance with respect to the surface of the cleaning roller is disposed. In a cleaning apparatus including a toner receiving member that stores toner removed from the carrier between the cleaning roller, a grounding member is connected to the toner receiving member.

  In the cleaning device having the above-described configuration, the toner receiving member is a bowl-shaped member along the peripheral surface of the cleaning roller.

  In the cleaning device having the above-described configuration, a cleaning blade that contacts the image carrier and scrapes off the toner on the surface thereof is provided on the downstream side in the rotation direction of the image carrier of the cleaning roller and on the lower side in the vertical direction. did.

  In the present invention, the cleaning device is mounted on the image forming apparatus.

  According to the configuration of the present invention, the cleaning roller that rotates in contact with the image carrier and removes the adhering material on the surface of the image carrier and the clearance between the cleaning roller and the surface of the cleaning roller are arranged and removed from the image carrier. In the cleaning device provided with the toner receiving member for storing the toner between the cleaning roller and the toner receiving member, the ground receiving member is connected to the toner receiving member. The charged toner can be removed through the toner receiving member. Thereby, even when the toner is stored for a long period of time, it is possible to prevent the toner from being excessively charged. Accordingly, it is possible to provide a cleaning device that can prevent the surface of the image carrier from adversely affecting the next charging and can maintain a suitable cleaning performance.

  In addition, since the toner receiving member is a bowl-shaped member along the peripheral surface of the cleaning roller, the space for storing the toner is further reduced, and pressure is applied from the periphery of the cleaning roller to apply the surface of the image carrier. The toner removed from the toner can be adhered to the surface of the cleaning roller. Thereby, it is possible to prevent the toner from being easily separated from the surface of the cleaning roller. Accordingly, it is possible to form a suitable toner layer on the surface of the cleaning roller, and it is possible to effectively polish the surface of the image carrier with the cleaning roller. As a result, in addition to preventing excessive charging of the toner, it is possible to further improve the cleaning performance for the surface of the image carrier.

  Further, since the cleaning roller is provided on the downstream side in the rotation direction of the image carrier and on the lower side in the vertical direction, a cleaning blade that contacts the image carrier and scrapes off the toner on the surface is provided. The toner receiving member can prevent the toner scraped off from the toner from dropping down immediately without adhering to the cleaning roller. Therefore, even if the cleaning roller is provided in the upper part of the housing of the cleaning device and the cleaning blade is provided below the cleaning roller, the toner charge is removed by the action of the toner receiving member connected to the grounding member. Thus, it is possible to effectively polish the surface of the image carrier with the cleaning roller while preventing excessive charging.

  In the present invention, since the cleaning device is mounted on the image forming apparatus, it is possible to prevent the toner stored in the toner receiving member from being excessively charged and the surface of the image carrier is charged next time. It is possible to obtain a high-performance image forming apparatus that can maintain a suitable cleaning performance without adversely affecting it.

  Hereinafter, embodiments of the present invention will be described with reference to FIGS.

  First, an image output operation of an image forming apparatus equipped with a cleaning device according to an embodiment of the present invention will be described with reference to FIG. FIG. 1 is a schematic vertical sectional front view of an image forming apparatus. This image forming apparatus is of a color printing type in which a toner image is transferred onto a sheet using an intermediate transfer belt.

  As shown in FIG. 1, a paper cassette 3 is disposed below the inside of the main body 2 of the image forming apparatus 1. The paper cassette 3 stores and accommodates paper P such as cut paper before printing. The sheets P are separated and sent one by one toward the upper left of the sheet cassette 3 in FIG. The paper cassette 3 can be pulled out horizontally from the front side of the main body 2.

  A first paper transport unit 4 is provided inside the main body 2 and on the left side of the paper cassette 3. The first paper transport unit 4 is formed substantially vertically along the left side surface of the main body 2. The first paper transport unit 4 receives the paper P sent out from the paper cassette 3 and transports the paper P vertically upward along the left side surface of the main body 2 to the secondary transfer unit 40.

  A manual paper feed unit 5 is provided above the paper cassette 3 and on the right side, which is the side opposite to the left side of the main body 2 where the first paper transport unit 4 is formed. . In the manual sheet feeding portion 5, paper P having a size not contained in the paper cassette 3, a paper to be fed one by one such as a thick paper and an OHP sheet are placed.

  A second paper transport unit 6 is provided on the left side of the manual paper feed unit 5. The second paper transport unit 6 is located immediately above the paper cassette 3, extends substantially horizontally from the manual paper feed unit 5 to the first paper transport unit 4, and joins the first paper transport unit 4. Then, the second paper transport unit 6 receives the paper P or the like sent from the manual paper feed unit 5 and transports it to the first paper transport unit 4 substantially horizontally.

  On the other hand, the image forming apparatus 1 receives document image data from an external computer (not shown). The information of the image data is sent to a laser irradiation unit 7 that is an exposure unit disposed above the second paper transport unit 6. The laser irradiation unit 7 irradiates the image forming unit 20 with laser light L controlled based on the image data.

  A total of four image forming units 20 are provided above the laser irradiation unit 7, and an intermediate transfer belt 8 using an intermediate transfer member in the form of an endless belt is provided above each image forming unit 20. The intermediate transfer belt 8 is wound around and supported by a plurality of rollers, and is rotated clockwise in FIG. 1 by a driving device (not shown).

  As shown in FIG. 1, the four image forming units 20 are of a so-called tandem system that are arranged in a line from the upstream side to the downstream side in the rotational direction along the rotational direction of the intermediate transfer belt 8. The four image forming units 20 are, in order from the upstream side, a magenta image forming unit 20M, a cyan image forming unit 20C, a yellow image forming unit 20Y, and a black image forming unit 20B. These image forming units 20 are replenished with a developer (toner) by a developer supply container and a conveying unit (not shown) corresponding to each color. In the following description, the identification symbols “M”, “C”, “Y”, and “B” are omitted unless particularly limited.

  In each image forming unit 20, an electrostatic latent image of a document image is formed by the laser light L irradiated by the laser irradiation unit 7 serving as an exposure unit, and the toner image is developed from the electrostatic latent image. The toner image is primarily transferred to the surface of the intermediate transfer belt 8 by the primary transfer unit 30 provided above each image forming unit 20. As the intermediate transfer belt 8 rotates, the toner image of each image forming unit 20 is transferred to the intermediate transfer belt 8 at a predetermined timing, so that the surface of the intermediate transfer belt 8 is magenta, cyan, yellow, or black. A color toner image is formed by superimposing the color toner images.

  A secondary transfer unit 40 including a secondary transfer roller 41 is disposed at a position where the intermediate transfer belt 8 is suspended on the sheet conveyance path. The color toner image on the surface of the intermediate transfer belt 8 is a secondary formed by the intermediate transfer belt 8 and the secondary transfer roller 41 being pressed against the paper P sent in synchronization by the first paper transport unit 4. Transferred at the transfer nip.

  After the secondary transfer, deposits such as toner remaining on the surface of the intermediate transfer belt 8 are cleaned for the intermediate transfer belt 8 provided upstream of the intermediate transfer belt 8 in the rotation direction of the magenta image forming unit 20M. It is cleaned and collected by the device 9.

  A fixing unit 10 is provided above the secondary transfer unit 40. The paper P carrying the unfixed toner image in the secondary transfer unit 40 is sent to the fixing unit 10 where the toner image is heated and pressed by the heat roller and the pressure roller to be fixed.

  A branch portion 11 is provided above the fixing portion 10. The sheet P discharged from the fixing unit 10 is discharged from the branching unit 11 to the sheet discharging unit 12 provided on the upper part of the image forming apparatus 1 when double-sided printing is not performed.

  The discharge port portion from which the paper P is discharged from the branch portion 11 toward the paper discharge portion 12 functions as the switchback portion 13. When performing duplex printing, the switchback unit 13 switches the transport direction of the paper P discharged from the fixing unit 10. Then, the sheet P is sent downward through the branching unit 11, the left side of the fixing unit 10, and the left side of the secondary transfer unit 40, and again passes through the first sheet transport unit 4 to the secondary transfer unit 40. Sent.

  Next, a detailed configuration around the image forming unit 20 of the image forming apparatus 1 will be described with reference to FIGS. 2 is a partially enlarged vertical cross-sectional view showing the periphery of the image forming unit, FIG. 3 is a perspective view showing the inside of the photosensitive drum and the cleaning device, and FIG. 4 is a perspective view of the toner receiving member. Since the four color image forming units 20 have the same structure, the identification symbols “M”, “C”, “Y”, and “B” are omitted as described above.

  As shown in FIG. 2, the image forming unit 20 includes a photosensitive drum 21 as an image carrier at the center thereof. In the vicinity of the photosensitive drum 21, a charging device 50, a developing device 60, a charge removal device 70, and a drum cleaning device 80 are arranged in this order along the rotation direction. The primary transfer unit 30 is provided between the developing device 60 and the charge removal device 70 along the rotation direction of the photosensitive drum 21.

  The photosensitive drum 21 extends in the paper width direction perpendicular to the paper conveyance direction in the image forming apparatus 1, that is, the depth direction of the paper surface in FIG. The photosensitive drum 21 is an inorganic photosensitive drum in which an amorphous silicon photosensitive layer, which is an inorganic photoconductive material, is provided on the outer side of a conductive roller-shaped substrate made of aluminum or the like by vacuum deposition or the like, and has a diameter of 30 mm. It is. The photosensitive drum 21 is rotated by a driving device (not shown) so that the peripheral speed thereof is substantially the same as the paper conveyance speed (150 mm / s).

  The charging device 50 includes a charging roller 52 in contact with the photosensitive drum 21 inside the housing 51. The charging roller 52 is in pressure contact with the photosensitive drum 21 with a predetermined pressure, and rotates according to the rotation of the photosensitive drum 21. By this charging roller 52, the surface of the photosensitive drum 21 is uniformly charged with a predetermined polarity and potential. The charging potential at this time is usually about 200 to 1000V. In the housing 51, a cleaning brush 53 is provided at a position separating the charging roller 52 from the photosensitive drum 21, and the surface of the charging roller 52 is cleaned by the cleaning brush 53.

  The developing device 60 includes a developing roller 62 and a supply screw 63 inside the housing 61. The developing roller 62 is in contact or non-contact with the developing system, and is provided in the vicinity of the photosensitive drum 21. A bias having the same polarity as the charging polarity of the photosensitive drum 21 is applied to the developing roller 62. The developing roller 62 charges the toner, which is a developer, and moves it to the electrostatic latent image on the surface of the photosensitive drum 21 to develop the electrostatic latent image.

  The developing device 60 uses a two-component toner obtained by mixing a magnetic carrier and a non-magnetic toner as a developer, but may be of a type using a magnetic or non-magnetic one-component toner. Absent. Further, in order to clean the surface of the photosensitive drum 21 by polishing, a small amount of powder of titanium oxide, alumina or the like is mixed in the toner as an abrasive. The toner is accommodated in a toner supply container (not shown), conveyed to a location of the developing device 60 by a conveying means (not shown), and replenished inside the housing 61 by a supply screw 63.

  The primary transfer unit 30 is provided with a primary transfer roller 31 that comes into contact with the photosensitive drum 21 via the intermediate transfer belt 8. The primary transfer roller 31 does not have a driving device, and rotates according to the rotation of the intermediate transfer belt 8 by contacting the intermediate transfer belt 8. The primary transfer roller 31 is applied with a primary transfer bias of minus 500 to minus 1000 V, which has a polarity different from the charging polarity of the photosensitive drum 21 or toner, as necessary.

  As shown in FIG. 1, the intermediate transfer belt 8 is wound around and supported by a plurality of rollers. The intermediate transfer belt 8 is constituted by an elastic belt in which a rubber layer is laminated on the surface of a base layer made of a synthetic resin. As materials, polyvinylidene fluoride (PVDF) and chloroprene rubber (CR) are used for the base layer, silicon and urethane, and polytetrafluoroethylene (PTFE) and urethane are used for the coating.

  The neutralization device 70 is disposed on the downstream side of the primary transfer unit 30 along the rotation direction of the photosensitive drum 21. The static eliminator 70 includes an LED (light emitting diode) 71 and a reflector 72. The LED 71 is attached to the upper surface of the housing 81 of the cleaning device 80. Instead of the LED 71, an EL (electroluminescence) light source, a fluorescent lamp, or the like can be used. The reflector 72 is provided above the LED 71 so as to cover the LED 71. The neutralization device 70 irradiates the photosensitive drum 21 with the neutralization light of the LED 71, thereby removing the charged charge on the surface and preparing for the charging process in the next image forming operation.

  The cleaning device 80 is disposed further downstream of the primary transfer unit 30 and the charge removal device 70 along the rotation direction of the photosensitive drum 21. As shown in FIGS. 2 and 3, the cleaning device 80 includes a cleaning roller 82 that is a rotating member, a cleaning blade 83, a toner receiving member 84, a grounding member 85, and a discharge screw 86 inside a housing 81. Yes.

  The cleaning roller 82 is provided in the upper part of the housing 81 so as to be pressed against the photosensitive drum 21 with a predetermined force by urging means (not shown) provided at both ends of the shaft portion. The cleaning roller 82 is configured by providing ethylene propylene rubber (EPDM) around a core metal, has a diameter of 16 mm, and has almost the same axial length as the photosensitive drum 21 (see FIG. 3). ).

  The cleaning roller 82 is rotated by a driving means (not shown) constituted by a motor or the like. In order to efficiently polish the surface of the photosensitive drum 21, it is necessary to rotate the cleaning roller 82 at a predetermined peripheral speed. As a result, the cleaning roller 82 is rotated in such a direction that the surface at the contact point with the photosensitive drum 21 moves in the same direction as the surface of the photosensitive drum 21, and the peripheral speed of the cleaning roller 82 is one of that of the photosensitive drum 21. .2x is set. The cleaning roller 82 collects deposits such as residual toner from the surface of the photosensitive drum 21 and also cleans the surface of the photosensitive drum 21 with the toner containing the abrasive adhered to the surface of the cleaning roller 82. Fulfill.

  The cleaning blade 83 is disposed on the downstream side of the cleaning roller 82 in the rotation direction of the photosensitive drum 21 and on the lower side in the vertical direction with respect to the cleaning roller 82 in the housing 81. The cleaning blade 83 is provided by being pressed with a predetermined force against the photosensitive drum 21 by an urging means (not shown). The cleaning blade 83 is a rectangular parallelepiped member made of urethane rubber, such as a plate extending in the drum axial direction, and has substantially the same axial length as the photosensitive drum 21. The cleaning blade 83 plays a role of cleaning so as to scrape off deposits such as toner remaining on the surface of the photosensitive drum 21.

  As shown in FIGS. 2 and 3, the toner receiving member 84 is disposed immediately below the cleaning roller 82 and between the cleaning blade 83 and the discharge screw 86. The toner receiving member 84 is configured by bending a thin plate-like member made of stainless steel (SUS) as shown in FIG. 4 and the like, and is arranged from the vicinity of the cleaning blade 83 toward the downstream side in the rotation direction of the cleaning roller 82. It has a bowl shape extending along the peripheral surface of 82, and has substantially the same length as the length of the cleaning roller 82 in the axial direction.

  The toner receiving member 84 leaves the upper portion of the toner receiving member 84 to partition the space in which the cleaning roller 82 and the cleaning blade 83 are disposed in the housing 81 from the space in which the discharge screw 86 is provided. The toner removed from the surface of the drum 21 is provided so as to be easily stored in a space near the peripheral surface of the cleaning roller 82.

  As shown in FIG. 2, a ground member 85 such as a ground wire is connected to the toner receiving member 84. The other end of the ground member 85 goes out of the housing 81 and is connected to the main body 2 of the image forming apparatus 1. The ground member 85 serves to remove charges from the toner receiving member 84 itself and the toner stored inside the toner receiving member 84.

  The discharge screw 86 is provided below the cleaning roller 82 in the housing 81. The discharge screw 86 extends from the inside of the housing 81 to a waste toner collection container (not shown) provided outside the image forming unit 20. The discharge screw 86 serves to discharge waste toner or the like in the housing 81 that has been removed from the surface of the photosensitive drum 21 and used for cleaning out of the housing 81, that is, to a waste toner collection container.

  The cleaning device 80 as described above uses the cleaning roller 82 and the cleaning blade 83 after the toner image on the surface of the photosensitive drum 21 is transferred to the intermediate transfer belt 8, and the toner remaining on the surface of the photosensitive drum 21. Remove deposits and clean.

  In this manner, the cleaning roller 82 that rotates in contact with the photosensitive drum 21 that is an image carrier and removes the deposits on the surface of the photosensitive drum 21 is disposed, and a clearance is provided with respect to the surface of the cleaning roller 82. In the cleaning device 80 including the toner receiving member 84 that stores the toner removed from the photosensitive drum 21 between the toner receiving member 84 and the cleaning roller 82, the ground member 85 is connected to the toner receiving member 84. Electric charge can be removed from the toner stored in the toner receiving member 84 for adhesion via the toner receiving member 84. Thereby, even when the toner is stored for a long period of time, it is possible to prevent the toner from being excessively charged. Accordingly, it is possible to prevent the surface of the photosensitive drum 21 from being adversely affected by the next charging, and it is possible to provide the cleaning device 80 capable of maintaining a suitable cleaning performance.

  Further, since the toner receiving member 84 is a bowl-shaped member along the peripheral surface of the cleaning roller 82, the space for storing the toner is further reduced, and pressure is applied from the periphery of the cleaning roller 82 to apply the surface of the photosensitive drum 21. The toner removed from the toner can adhere to the surface of the cleaning roller 82. Thereby, it is possible to prevent the toner from being easily separated from the surface of the cleaning roller 82. Therefore, a suitable toner layer can be formed on the surface of the cleaning roller 82, and the surface of the photosensitive drum 21 can be effectively polished by the cleaning roller 82. As a result, in addition to preventing excessive charging of the toner, it is possible to further improve the cleaning performance for the surface of the photosensitive drum 21.

  Further, a cleaning blade 83 that contacts the photosensitive drum 21 and scrapes off toner on the surface thereof is provided on the downstream side in the rotational direction of the photosensitive drum 21 with respect to the cleaning roller 82 and on the lower side in the vertical direction. The toner receiving member 84 can prevent the toner scraped from the surface of the drum 21 from dropping immediately without adhering to the cleaning roller 82. Therefore, even if the cleaning roller 82 is provided in the upper part of the housing 81 of the cleaning device 80 and the cleaning blade 83 is provided below the cleaning roller 82, the operation of the toner receiving member 84 to which the ground member 85 is connected. Thus, it is possible to effectively perform the polishing of the surface of the photosensitive drum 21 by the cleaning roller 82 while preventing the toner from being excessively charged by removing the charge.

  In the present invention, since the cleaning device 80 is mounted on the image forming apparatus 1, excessive charging of the toner stored in the toner receiving member 84 can be prevented, and the surface of the photosensitive drum 21 is charged next time. Thus, it is possible to obtain a high-performance image forming apparatus 1 capable of maintaining a suitable cleaning performance without adversely affecting the image quality.

  Although the embodiments of the present invention have been described above, the scope of the present invention is not limited to these embodiments, and various modifications can be made without departing from the spirit of the invention.

  For example, in the embodiment of the present invention, the cleaning blade 83 is arranged on the lower side in the vertical direction with respect to the cleaning roller 82 that is a rotating member, but is arranged on the upper side in the vertical direction with respect to the cleaning roller 82. It may be a different structure. Even in such a structure, by connecting the grounding member 85 to the toner receiving member 84, the same operation and effect as in the present embodiment can be obtained.

  Further, the image forming apparatus 1 is of a color printing type in which the toner image is transferred onto the paper P using the intermediate transfer belt 8, but the type of the image forming apparatus is not limited to this, and the intermediate transfer belt is not limited thereto. It may be a model that does not use, or a model for monochrome printing.

  The present invention can be used in general cleaning apparatuses that transfer a toner image onto a sheet and then remove the adhering matter such as toner remaining on the surface of the image carrier to perform cleaning.

1 is a schematic vertical sectional front view of an image forming apparatus equipped with a cleaning device according to an embodiment of the present invention. FIG. 2 is a partially enlarged vertical sectional view showing the periphery of the image forming unit in FIG. 1. It is a perspective view which shows a photoconductor drum and the inside of a cleaning apparatus. FIG. 6 is a perspective view of a toner receiving member.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Image forming apparatus 8 Intermediate transfer belt 20 Image forming part 21 Photosensitive drum (image carrier)
80 Cleaning Device 81 Housing 82 Cleaning Roller 83 Cleaning Blade 84 Toner Receiving Member 85 Grounding Member

Claims (4)

A cleaning roller that rotates in contact with the image carrier and removes deposits on the surface of the image carrier, and a clearance with respect to the surface of the cleaning roller is disposed between the cleaning roller and the toner removed from the image carrier. A cleaning device including a toner receiving member stored in
A cleaning device, wherein a grounding member is connected to the toner receiving member.   The cleaning device according to claim 1, wherein the toner receiving member is a bowl-shaped member along a peripheral surface of the cleaning roller.   2. The cleaning blade according to claim 1, further comprising a cleaning blade that contacts the image carrier and scrapes off the toner on the surface thereof, on the downstream side in the rotation direction of the image carrier of the cleaning roller and on the lower side in the vertical direction. 3. The cleaning device according to 2.   An image forming apparatus comprising the cleaning device according to claim 1.

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