JP2009025773A - Cleaning device and image forming apparatus loaded with the same - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a cleaning device capable of forcibly sticking an abrasive that is likely to fall off a toner surface to the surface of a cleaning roller, and capable of maintaining cleanability of the abrasive suitable to the surface of an image carrier. <P>SOLUTION: The cleaning device 60 using magnetic toner includes: the cleaning roller 62 having a magnetic shaft part 62a, for removing a deposit on the surface of the photoreceptor drum 21; and a magnet member 67 disposed facing the cleaning roller 62 at a prescribed distance from the surface of the cleaning roller 62. Thus, the magnetic toner is attracted and deposited on the magnet member 67 to be formed like a brush, and then, the so-called magnetic brush can catch the abrasive that is likely to fall off the surface of the toner. By making the magnetic brush rub the surface of the cleaning roller 62, the abrasive caught by the magnetic brush can be forcibly stuck to the surface of the cleaning roller 62. <P>COPYRIGHT: (C)2009,JPO&INPIT

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. The residual toner adhering to the surface of the photosensitive drum becomes an obstacle to the next new image formation, so that it needs to be cleaned. As a cleaning method used for such a purpose, a method of moving and collecting residual toner on the rotating member by pressing a cleaning roller, a rotating brush, or the like that is a rotating member on the surface of the photosensitive drum, or a surface of the photosensitive drum A method of scraping residual toner by bringing a cleaning blade into contact therewith, or a cleaning method combining these methods is widely known.

  On the other hand, when an amorphous silicon photoconductor is used as the photoconductor, it is known that discharge products generated by the discharge of the charging device are likely to adhere to the surface of the photoconductor. When this discharge product absorbs moisture, the electrical resistance on the surface of the photoreceptor is lowered, and a problem of image flow that disturbs the electrostatic latent image may occur. For this reason, a small amount of abrasive is mixed in the toner, and the cleaning roller and the cleaning blade are used in combination to remove the residual toner adhering to the surface of the photosensitive member, and a small amount of toner is carried on the surface of the cleaning roller. There is known a method of cleaning by discharging the discharge product adhering to the surface of the photoreceptor.

Patent Documents 1 and 2 show examples of a cleaning method for removing the discharge products adhering to the surface of the photosensitive drum using the cleaning roller and the cleaning blade as described above. The image forming apparatus described in Patent Documents 1 and 2 includes a cleaning roller (sliding roller, polishing roller) that contacts the photosensitive drum and polishes the surface thereof, and a toner regulating member (from the lower side of the cleaning roller). By pressing the scraper, a toner layer necessary for polishing the surface of the photosensitive drum is formed on the surface of the cleaning roller.
Japanese Patent Laid-Open No. 11-2996 (page 2-3, FIG. 2) JP 2000-276026 A (page 3, FIG. 3)

  Here, the abrasive mixed in the toner is generally in an amount of 0.5 to 2.0% by weight, and is dispersed and adhered to the toner surface. Since the abrasive is not attached to the toner by utilizing a special action, it may fall off the toner surface with a slight impact. Nearly half of the abrasive may fall off the toner surface during development or transfer. Therefore, it is necessary to attach a lot of the less abrasive to the cleaning roller and effectively use it for polishing the surface of the photosensitive drum by the cleaning roller.

  However, no special consideration is given to the abrasive in this situation in the image forming apparatuses described in Patent Documents 1 and 2. As a result, even if a toner layer can be formed on the surface of the cleaning roller using the toner regulating member (scraper), the amount of abrasive necessary for polishing the surface of the photosensitive drum may be insufficient. As a result, the surface of the photosensitive drum is not sufficiently polished by the cleaning roller, and there is a high possibility that the discharge product attached to the surface of the photosensitive member cannot be removed.

  SUMMARY OF THE INVENTION The present invention has been made in view of the above points, and after a toner image is transferred onto a sheet, the toner is removed from the surface of a toner in a cleaning device that removes and removes deposits such as toner remaining on the surface of the image carrier. It is an object of the present invention to provide a cleaning device capable of forcibly adhering a polishing agent that easily adheres to the surface of a cleaning roller and capable of maintaining a suitable cleaning performance for the surface of an image carrier by the polishing agent. 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 provides a cleaning device using a magnetic toner and having a cleaning roller that removes deposits on the surface of the image carrier while rotating in contact with the image carrier. The shaft portion is made of a magnetic material, and the magnet member is arranged so as to face the cleaning roller surface at a predetermined distance.

  In the cleaning device having the above-described configuration, the distance between the cleaning roller surface and the magnet member is such that the magnetic flux density by the magnet member is 100 gauss or more on the cleaning roller surface.

  In the cleaning device having the above-described configuration, the cleaning roller is disposed on the upper side in the vertical direction with respect to the axial center of the image carrier.

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

  In the image forming apparatus having the above configuration, the image carrier includes an amorphous silicon photoconductor.

  According to the configuration of the present invention, in a cleaning device using a magnetic toner and having a cleaning roller that removes deposits on the surface of the image carrier while rotating in contact with the image carrier, the shaft portion of the cleaning roller is a magnetic body. Since the magnet member is arranged so as to face the cleaning roller surface at a predetermined distance, the abrasive itself is not attracted to the magnet member, and the magnetic toner is attracted and adhered to the magnet member. The so-called magnetic brush makes it possible to capture an abrasive that easily falls off the toner surface. By rubbing the surface of the cleaning roller with this magnetic brush, the abrasive captured by the magnetic brush can be forced to adhere to the surface of the cleaning roller. Thereby, effective cleaning for removing discharge products adhering to the surface of the image carrier can be performed. Therefore, it is possible to provide a cleaning device capable of maintaining a suitable cleaning performance while preventing the occurrence of image flow on the surface of the image carrier.

  Further, the distance between the cleaning roller surface and the magnet member is such that the magnetic flux density by the magnet member is 100 gauss or more on the cleaning roller surface, so that it is appropriate for capturing the abrasive. A strong magnetic brush made of magnetic toner can be formed. Further, by using a magnetic brush having such a strength, it is possible to attach an abrasive to the surface of the cleaning roller so that it does not easily fall off from the surface of the cleaning roller. Accordingly, the amount of abrasive on the surface of the cleaning roller can be increased, and more effective cleaning can be performed on the surface of the image carrier.

  In addition, since the cleaning roller is disposed on the upper side in the vertical direction with respect to the axial center of the image carrier, in the cleaning device having such a configuration, a magnetic brush made of magnetic toner is formed from the toner surface. It is possible to capture an abrasive that easily falls off. Therefore, even in a cleaning device arranged above the image carrier for the purpose of space saving, an appropriate amount of abrasive can be reliably adhered to the surface of the cleaning roller, while preventing the occurrence of image flow, It is possible to perform effective cleaning of the surface of the image carrier.

  In the present invention, since the cleaning device is mounted on the image forming apparatus, an abrasive that easily falls off the toner surface can be forcibly adhered to the surface of the cleaning roller. A high-performance image forming apparatus capable of maintaining a suitable cleaning performance can be provided.

  In addition, a photoconductor composed of amorphous silicon is used in many image forming apparatuses because it has high hardness, excellent wear resistance, and a very long life. However, on the other hand, there is also a problem that image flow is likely to occur due to discharge products adhering to the surface of the photoreceptor. In order to solve such a problem, it is possible to prevent adhesion of discharge products to the surface of the photoreceptor by combining the image forming apparatus of the present invention with a photoreceptor composed of amorphous silicon. Therefore, it is possible to form a high-quality image without causing occurrence of an image and to obtain an image forming apparatus having a longer life.

  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. In FIG. 1, a solid line arrow indicates a sheet conveyance path and a conveyance direction, and a one-dot chain line arrow indicates a laser beam L.

  As shown in FIG. 1, a paper feed cassette 3, which is a paper feed unit, is disposed below the inside of the main body 2 of the image forming apparatus 1. The paper feed 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 feed 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 to the left of the paper feed cassette 3. The first paper transport unit 4 is formed substantially vertically along the left side surface of the main body 2. Then, the first paper transport unit 4 receives the paper P sent out from the paper feed cassette 3 and transports it to the transfer unit 30 vertically upward along the left side surface of the main body 2.

  A manual paper feed unit 5 is provided above the paper feed cassette 3 at a location 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. Yes. In the manual sheet feeder 5, paper P of a size that is not contained in the paper cassette 3, thick paper, and OHP sheets that are to be fed one by one 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 feed 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, a document feeding unit 7 is provided on the upper surface of the main body 2 of the image forming apparatus 1, and a document image reading unit 8 is provided below the document feeding unit 7. When a user copies a document, a document on which an image such as a character, a figure, or a pattern is drawn is stacked on the document feeding unit 7. The document feeding unit 7 separates the documents one by one and sends the document, and the document image reading unit 8 reads the image data. The information of the image data is sent to the exposure device 9 disposed above the second paper transport unit 6 and at the center of the main body 2. Laser light L controlled based on the image data is emitted toward the image forming unit 20 by the exposure device 9.

  An image forming unit 20 and a transfer unit 30 are provided above the first paper transport unit 4 and to the left of the exposure device 9. In the image forming unit 20, an electrostatic latent image of a document image is formed by the laser light L emitted by the exposure device 9, and a toner image is developed from the electrostatic latent image. The toner is supplied to the image forming unit 20 from a toner container 10 provided above the exposure device 9. The toner image formed by the image forming unit 20 is transferred by the transfer unit 30 to the pre-printing paper P sent in synchronization by the first paper transport unit 4.

  A fixing device 11 is provided above the transfer unit 30. The paper P carrying the unfixed toner image in the transfer unit 30 is sent to the fixing device 11 where the toner image is heated and pressed by a heat roller and a pressure roller to be fixed.

  A branch portion 12 is provided above the fixing device 11. The sheet P discharged from the fixing device 11 is discharged from the branching unit 12 to the in-body sheet discharging unit 13 provided in the cylinder 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 12 toward the in-body paper discharge portion 13 functions as a switchback portion 14. When performing duplex printing, the switchback unit 14 switches the transport direction of the paper P discharged from the fixing device 11. Then, the paper P passes through the branching section 12 and is sent downward through a double-sided printing paper conveyance path 15 provided on the left side of the fixing device 11 and on the left side of the transfer section 30, and again the first paper conveyance section 4 is sent to the transfer unit 30.

  Next, a detailed configuration around the image forming unit 20 of the image forming apparatus 1 will be described with reference to FIG. 2 in addition to FIG. FIG. 2 is a partially enlarged vertical cross-sectional view showing the periphery of the image forming unit.

  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 40, a developing device 50, and a cleaning device 60 are sequentially arranged along the rotation direction. The transfer unit 30 is provided between the developing device 50 and the cleaning device 60 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 (125 mm / s).

  The charging device 40 is a scorotron charging device using a corona discharge charger. A corotron charging device using a corona discharge charger may also be used. By this charging device 40, the surface of the photosensitive drum 21 is uniformly charged with a predetermined polarity and potential. The charging potential at this time is normally plus 350V.

  The developing device 50 includes a developing roller 52 inside the housing 51. The developing roller 52 is provided in the vicinity of the photosensitive drum 21 in which the developing method is magnetic jumping development. A bias having the same polarity as the charging polarity of the photosensitive drum 21 is applied to the developing roller 52. The developing roller 52 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. Further, the toner is a styrene-acrylic magnetic one-component toner, and is accommodated in the toner container 10 shown in FIG. 1 and transported to a location of the developing device 50 by transport means (not shown) and replenished inside the housing 51. The The developing method of the developing device is not limited to the above. In addition, the toner may be of another type except that it has magnetism.

  The transfer unit 30 is provided with a transfer roller 31. The transfer roller 31 is pressed against the photosensitive drum 21 from the left in FIG. 2 to form a transfer nip portion through which the paper P is inserted. The transfer roller 31 rotates according to the rotation of the photosensitive drum 21 by contacting the photosensitive drum 21 without having a driving device. Further, a transfer bias of minus 500 to minus 1000 V having a polarity different from the charging polarity of the photosensitive drum 21 and the toner is applied to the transfer roller 31 as necessary.

  As shown in FIG. 2, the cleaning device 60 is disposed on the further downstream side of the transfer unit 30 along the rotation direction of the photosensitive drum 21 and on the upper side in the vertical direction with respect to the axial center of the photosensitive drum 21. Yes. The cleaning device 60 includes a housing 61 that includes a cleaning roller 62, a cleaning blade 63, a seal member 64, a scraper 65 that is a toner regulating member, a toner discharge screw 66, and a magnet member 67.

  The cleaning roller 62 is provided in the lower left portion of the housing 61 by being pressed against the photosensitive drum 21 with a predetermined force by biasing means (not shown) provided at both ends of the shaft portion. The cleaning roller 62 is configured by providing ethylene propylene rubber (EPDM) with a thickness of 1.5 mm around a shaft portion 62 a having a diameter of 11 mm. The cleaning roller 62 has a diameter of 14 mm and is substantially the same axis as the photosensitive drum 21. It has a directional length. The shaft portion 62a of the cleaning roller 62 is made of a sulfur free-cutting steel (SUM) that is a magnetic material.

  The cleaning roller 62 is rotated by a driving device (not shown) composed of 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 62 at a predetermined peripheral speed. As a result, the cleaning roller 62 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 circumferential speed of the cleaning roller 62 is one of that of the photosensitive drum 21. .2x is set. The cleaning roller 62 collects deposits such as residual toner from the surface of the photoconductive drum 21 and cleans the surface of the photoconductive drum 21 with the toner containing the abrasive adhered to the surface of the cleaning roller 62. Fulfill.

  The cleaning blade 63 is disposed downstream of the cleaning roller 62 in contact with the photosensitive drum 21 in the drum rotation direction. The cleaning blade 63 is provided by being pressed against the photosensitive drum 21 with a predetermined force by an urging means (not shown). The cleaning blade 63 is a rectangular parallelepiped member such as a 2.2 mm thick plate made of polyurethane rubber and extending in the drum axial direction. The cleaning blade 63 has substantially the same axial length as the photosensitive drum 21. is doing. The cleaning blade 63 plays a role of cleaning so as to scrape off deposits such as toner remaining on the surface of the photosensitive drum 21.

  On the other hand, a seal member 64 is provided on the upstream side of the contact portion between the cleaning roller 62 and the photosensitive drum 21 in the drum rotation direction. The seal member 64 is attached to the housing 61 such that the tip of the seal member 64 abuts the surface of the photosensitive drum 21 so that the toner in the housing 61 does not fall into the lower sheet conveyance path. The seal member 64 is made of a polyurethane film having a thickness of 50 μm.

  As shown in FIG. 2, the scraper 65 that is a toner regulating member is provided between the cleaning roller 62 and the toner discharge screw 66. The scraper 65 is disposed immediately downstream of the contact point between the cleaning roller 62 and the photosensitive drum 21 with respect to the rotation direction of the cleaning roller 62. The scraper 65 is made of a thin sheet-like member made of stainless steel and having a thickness of 80 μm, and has almost the same length as the axial length of the cleaning roller 62.

  Further, the scraper 65 is supported by a support member 68 provided above the cleaning roller 62 in the housing 61, and is disposed so as to extend toward the cleaning roller 62. The scraper 65 is in contact with the surface of the cleaning roller 62 at one flat surface at the tip. Thus, the scraper 65 is attached in such a manner that the direction extending from the support member 68 toward the cleaning roller 62 and the moving direction of the surface of the cleaning roller 62 at the contact point with the cleaning roller 62 are opposed to each other.

  The toner discharge screw 66 is provided in the housing 61 slightly above the cleaning roller 62. The toner discharge screw 66 is a rotating member that rotates about an axis substantially parallel to the axis of the cleaning roller 62, and is a waste toner collection container (not shown) provided from the inside of the housing 61 to the outside of the image forming unit 20. ). The toner discharge screw 66 serves to discharge waste toner or the like in the housing 61 that has been removed from the surface of the photosensitive drum 21 and used for cleaning to the outside of the housing 61, that is, to a waste toner collection container.

  The main configuration of such a cleaning device 60 is that, after the toner image on the surface of the photosensitive drum 21 is transferred to the paper P, the toner remaining on the surface of the photosensitive drum 21 using the cleaning roller 62 and the cleaning blade 63 is used. Remove deposits and clean.

  In order to further improve the cleaning performance, the cleaning device 60 includes two magnet members 67 in the vicinity of the cleaning roller 62.

  The two magnet members 67 are separated from the scraper 65 by a predetermined distance from the surface of the cleaning roller 62 on the inner side of the support member 68 on the downstream side in the rotational direction of the cleaning roller 62 and on the inner wall of the housing 61 on the downstream side in the rotational direction. Are arranged to face each other. Each of the magnet members 67 is composed of a sheet-like rubber magnet, has a thickness of 2 mm, a surface magnetic flux density of 600 gauss, and substantially the same length as the axial direction length of the cleaning roller 62.

  Since a magnetic field is generated around these magnet members 67, the magnetic toner is attracted and adhered to the magnet member 67, and a so-called magnetic brush made of the magnetic toner is formed on the surface thereof. The magnetic brush can capture an abrasive that easily falls off the toner surface. The magnet member 67 can forcibly attach the abrasive captured by the magnetic brush to the surface of the cleaning roller 62 by rubbing the surface of the cleaning roller 62 with the magnetic brush.

  Next, setting of the distance between the surface of the cleaning roller 62 and the magnet member 67 will be described with reference to FIG. 3 in addition to FIG. FIG. 3 is a graph showing the relationship between the distance from the surface of the magnet member and the magnetic flux density.

  With respect to the magnet member 67 having a surface magnetic flux density of 600 gauss, as shown in FIG. 3, it can be seen that the magnetic flux density attenuates as the distance from the surface increases. This magnetic flux density is attenuated in inverse proportion to the square of the distance.

  In order to form a magnetic brush having an appropriate strength to capture the abrasive with magnetic toner on the surface of the magnet member 67, the magnetic flux density of the magnet member 67 should be 100 gauss or more on the surface of the cleaning roller 62. I know that is good. According to FIG. 3, it can be seen that the region where the magnetic flux density is 100 gauss or more is the range from the surface of the magnet member 67 to about 2.5 mm. Thereby, in this embodiment, the distance from the surface of the cleaning roller 62 shown in FIG. 2 to the surface of the magnet member 67 is set to 1.0 mm.

  The magnet member 67 used in the present embodiment has a thickness of 2 mm. However, if the magnet member is a 1 mm magnet member having a thickness of half, for example, the magnetic flux density is about half that. Therefore, when a magnet member having a thickness of 1 mm is disposed so as to face the cleaning roller 62, a magnetic flux density of 100 Gauss or more is obtained, and a magnetic brush having an appropriate strength for capturing an abrasive with toner is formed. In this case, it is desirable to set the distance from the surface of the cleaning roller 62 to the surface of the magnet member within 1.25 mm.

  In this manner, in the cleaning device 60 including the cleaning roller 62 using the magnetic toner and removing the deposits on the surface while rotating in contact with the photosensitive drum 21 as the image carrier, the cleaning roller 62 is Since the shaft portion 62a is made of steel that is a magnetic material and the magnet member 67 is arranged in a form facing the cleaning roller 62 with a predetermined distance from the surface, the abrasive itself is not attracted to the magnet member 67. Magnetic toner is attracted and adhered to the magnet member 67 to form a brush, and this so-called magnetic brush can capture an abrasive that easily falls off the toner surface. By rubbing the surface of the cleaning roller 62 with this magnetic brush, the abrasive captured by the magnetic brush can be forcibly attached to the surface of the cleaning roller 62. As a result, it is possible to perform effective cleaning for removing the discharge products adhering to the surface of the photosensitive drum 21. Therefore, it is possible to provide the cleaning device 60 that can maintain a suitable cleaning performance while preventing the occurrence of image flow on the surface of the photosensitive drum 21.

  The distance between the surface of the cleaning roller 62 and the magnet member 67 is a distance at which the magnetic flux density by the magnet member 67 is 100 gauss or more on the surface of the cleaning roller 62. A magnetic brush made of magnetic toner can be formed. Further, by using the magnetic brush having such strength, it is possible to adhere the abrasive to the surface of the cleaning roller 62 so that the magnetic brush does not easily fall off from the surface of the cleaning roller 62. Accordingly, the amount of abrasive on the surface of the cleaning roller 62 can be increased, and more effective cleaning can be performed on the surface of the photosensitive drum 21.

  Further, since the cleaning roller 62 is disposed on the upper side in the vertical direction with respect to the axial center of the photosensitive drum 21, the cleaning device 60 having such a configuration forms a magnetic brush made of magnetic toner and falls off the toner surface. It is possible to capture an abrasive that is easy to do. Therefore, even with the cleaning device 60 disposed above the photosensitive drum 21 for the purpose of space saving, an appropriate amount of abrasive can be reliably adhered to the surface of the cleaning roller 62, and the occurrence of image flow can be prevented. However, effective cleaning of the surface of the photosensitive drum 21 can be performed.

  In the present invention, since the cleaning device 60 is mounted on the image forming apparatus 1, it is possible to forcibly attach the abrasive that easily falls off the toner surface to the surface of the cleaning roller 62, and the surface of the photosensitive drum 21 by the abrasive. Therefore, it is possible to provide a high-performance image forming apparatus 1 capable of maintaining a suitable cleaning performance.

  A photoreceptor composed of amorphous silicon is used in many image forming apparatuses because it has high hardness, excellent wear resistance, and a very long life. However, on the other hand, there is also a problem that image flow is likely to occur due to discharge products adhering to the surface of the photoreceptor. In order to solve such a problem, it is possible to prevent adhesion of discharge products to the surface of the photosensitive member by combining the image forming apparatus 1 of the present invention with a photosensitive member made of amorphous silicon. A high-quality image can be formed without causing a flow, and the image forming apparatus 1 having a longer life can be obtained.

  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 image forming apparatus 1 including the cleaning device 60 is described as an example of a monochrome printing model, but the type of the image forming apparatus is not limited thereto. A model for transferring a toner image onto a sheet using an intermediate transfer member or a color printing model using a plurality of color toners may be used.

  In this embodiment, a rubber magnet is used as the magnet member 67, but a ferrite magnet or the like may be used. In the case of a ferrite-based magnet, the magnetic flux density is higher than that of the rubber magnet. Therefore, the distance between the surface of the cleaning roller 62 and the magnet member 67 can be set longer than in the above embodiment.

  INDUSTRIAL APPLICABILITY The present invention can be used in a cleaning device that transfers toner images onto paper and then removes and removes deposits such as toner remaining on the surface of the image carrier.

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 an image forming unit of the image forming apparatus of FIG. It is a graph which shows the relationship between the distance from the magnet member surface, and its magnetic flux density.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Image forming apparatus 2 Main body 20 Image forming part 21 Photosensitive drum (image carrier)
60 Cleaning Device 61 Housing 62 Cleaning Roller 63 Cleaning Blade 64 Seal Member 65 Scraper 66 Toner Discharge Screw 67 Magnet Member

Claims (5)

In a cleaning device using a magnetic toner and having a cleaning roller that removes deposits on the surface while rotating in contact with the image carrier,
The cleaning device is characterized in that a shaft portion of the cleaning roller is made of a magnetic material, and a magnet member is arranged in a form facing the cleaning roller surface at a predetermined distance.   The cleaning apparatus according to claim 1, wherein the distance between the cleaning roller surface and the magnet member is a distance at which a magnetic flux density by the magnet member is 100 gauss or more on the cleaning roller surface.   The cleaning device according to claim 1, wherein the cleaning roller is disposed on an upper side in a vertical direction with respect to an axial center of the image carrier.   An image forming apparatus comprising the cleaning device according to claim 1.   The image forming apparatus according to claim 4, wherein the image carrier includes an amorphous silicon photoconductor.

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