JP2008304784A - Sealing structure and image forming apparatus with the same - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a sealing structure capable of securely preventing toner from leaking out of the axial direction of a rotating member, nor preventing a fault such as melting or caking of toner. <P>SOLUTION: In the cleaning device 60, the sealing structure 80 for preventing a toner leakage is disposed between a cleaning brush 62 and a wall 61a holding the cleaning brush so that it is rotatable. The sealing structure 80 has: a circumferential groove 81 formed in the surface of the shaft 62a of the cleaning brush 62; and a film-like sealing member 82 that has a circular hole 82a having an inside diameter smaller than the outside diameter of the shaft 82a but greater than the inside diameter of the groove 81 and that is disposed in the groove 81 with the shaft 62a passed through the hole 82a. One of the faces of the sealing member 82 is disposed in contact with the internal wall of the groove 81 and the other face is in contact with the wall 61a. This makes it possible to prevent a leakage of toner such that the sealing member 82 is in contact with the cleaning brush 62 in the smallest contact area possible. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to a toner seal structure applicable to a developing device or a cleaning device of an image forming apparatus represented by a copying machine or a printer. The present invention also relates to an image forming apparatus provided with this seal structure.

  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 the developing device which is the main part of the image forming operation as described above, generally, as a method for developing an electrostatic latent image, toner is attached to the surface of the developing roller which is a rotating member, and the image is developed from the surface of the developing roller. A technique is adopted in which the toner is moved to the surface of the carrier by electrostatic force.

  On the other hand, after the toner image is transferred to the paper, a small amount of toner may remain on the surface of the photosensitive drum without being transferred to the paper. 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 to the rotating member by pressing a cleaning roller or a cleaning brush as a rotating member against 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.

Here, for the purpose of preventing contamination inside the image forming apparatus and maintaining suitable image quality, in the developing device and the cleaning device, the toner is moved outward in the axial direction from the bearing portion such as the developing roller or the cleaning roller that is the rotating member. In order to prevent leakage, seal structures are provided at locations on both ends of the rotating member in the axial direction. An example of an image forming apparatus using such a seal structure for a developing device can be seen in Japanese Patent Application Laid-Open No. 2003-133260. In the developing device of the image forming apparatus described in Patent Document 1, a recess that fits into the end of the developing roller is provided between both end surfaces in the axial direction of the developing roller that is a rotating member and the side plate of the developing device. A seal member is disposed.
Japanese Unexamined Patent Publication No. 4-367880 (page 3, FIG. 2)

  In the developing device of the image forming apparatus described in Patent Document 1, a seal in which a seal member provided with a recess to be fitted to the end of the developing roller is disposed at both ends in the axial direction of the developing roller that is a rotating member. The structure has the effect of preventing the toner from leaking outward in the axial direction. However, since this seal structure is in pressure contact with the seal member on the entire end surface of the roller portion of the developing roller, a frictional force always acts on the entire end surface. As a result, the roller end face of the developing roller and the contact surface of the seal member are significantly worn, and this portion may be deteriorated at an early stage. Therefore, there is a possibility that toner leakage starts to occur at an early stage. And, in order to prevent such wear of the developing roller and the seal member, if the durability of these members is increased, there is a risk that a significant cost increase occurs.

  In addition, there is a concern that frictional heat is likely to be generated due to the frictional force acting on the entire end surface of the developing roller. This may cause problems such as toner melting and fixing. As a result, there is a high possibility of causing problems such as breakage of the developing roller and deterioration of image quality.

  The present invention has been made in view of the above points, and is provided at a low cost in a seal structure that is provided between a rotating member and a wall portion that rotatably holds the rotating member and prevents toner leakage. To provide a seal structure that can prevent leakage of toner to the outside in the axial direction of a rotating member with a simpler structure that can be carried out without causing troubles such as melting and fixing of toner. With the goal. It is another object of the present invention to provide a high-performance image forming apparatus that can maintain a suitable image quality by providing such a seal structure.

  In order to solve the above-described problems, the present invention provides a seal structure provided between a rotating member and a wall portion that rotatably holds the rotating member, and prevents the toner from leaking. A groove portion provided in the circumferential direction and a circular hole whose inner diameter is smaller than the outer diameter of the shaft portion and larger than the inner diameter of the groove portion are provided on the surface of the portion, and the hole is disposed in the groove portion through the shaft portion. A film-like seal member, and one surface of the film-like seal member is in contact with the inner wall of the groove and the other surface is in contact with the wall.

  Further, in the seal structure having the above configuration, the seal member is in contact with the inner wall of the groove portion of the rotating member in a pressure contact state.

  Further, the seal structure having the above configuration includes a block-like elastic member in which a hole having an inner diameter larger than the outer diameter of the shaft portion is provided between the seal member and the wall portion.

  In the present invention, the seal structure having the above-described configuration is provided for a cleaning brush that is a rotating member of a cleaning device for cleaning the surface of an image carrier of the image forming apparatus.

  In the image forming apparatus having the above-described configuration, the groove portion is an adhesive flow stop groove for bonding the brush portion to the shaft portion of the cleaning brush.

  According to the configuration of the present invention, in the seal structure that is provided between the rotating member and the wall portion that rotatably holds the rotating member and prevents the toner from leaking, the surface of the shaft portion of the rotating member is provided. A groove portion provided in the circumferential direction, and a circular hole having an inner diameter smaller than the outer diameter of the shaft portion and larger than the inner diameter of the groove portion, and a film-like seal disposed in the groove portion through the shaft portion. The film-like sealing member has one surface in contact with the inner wall of the groove portion and the other surface in contact with the wall portion. It is possible to prevent the toner from leaking. Thereby, it is not necessary to make a sealing member contact a rotating member with a big contact pressure, and progress of wear can be suppressed. It is also possible to suppress the generation of frictional heat at the seal location. Therefore, a seal that can be implemented at low cost and can prevent leakage of toner to the outside in the axial direction of the rotating member without causing troubles such as melting and fixing of the toner with a simpler configuration. A structure can be obtained.

  In addition, since the seal member is in contact with the inner wall of the groove portion of the rotating member in a pressure contact state, the seal member and the rotating member are in close contact with each other. Thereby, the sealing performance between the sealing member and the rotating member is improved. Therefore, it is possible to enhance the effect of preventing the leakage of toner to the outside in the axial direction of the rotating member.

  In addition, since the block-shaped elastic member having an inner diameter larger than the outer diameter of the shaft portion is provided between the seal member and the wall portion, the seal member is provided by the action of the elastic member. However, the state which is always in pressure contact with the rotating member can be maintained. Moreover, both contact areas can be made uniform. Accordingly, it is possible to prevent the leakage of toner even in a minute region of the seal portion. As a result, the effect of preventing the leakage of the toner to the outside in the axial direction of the rotating member can be further improved.

  Further, in the present invention, the seal structure having the above-described configuration is provided for the cleaning brush that is a rotating member of the cleaning device for cleaning the surface of the image carrier of the image forming apparatus. With a simple configuration, it is possible to reliably prevent toner leakage to the outside in the axial direction of the cleaning brush without causing troubles such as melting and fixing of the toner, and it is possible to continue to maintain a suitable image quality. And a high-performance image forming apparatus can be obtained.

  In the image forming apparatus having the above-described configuration, the groove portion is an adhesive flow stop groove for bonding the brush portion to the shaft portion of the cleaning brush. The groove for preventing the outflow can be used for a seal structure for preventing the leakage of the toner. Therefore, it is possible to save the labor and cost required for providing the groove part anew because of the seal structure. As a result, it is possible to reliably prevent the toner from leaking to the outside in the axial direction of the cleaning brush while preventing the occurrence of troubles such as melting and fixing of the toner with a simple configuration that can be implemented at a lower cost.

  Hereinafter, embodiments of the present invention will be described with reference to FIGS. In the image forming apparatus, the seal structure according to this embodiment is provided for a cleaning brush that is a rotating member of a cleaning device that cleans the surface of a photosensitive drum that is an image carrier.

  First, an image output operation of an image forming apparatus having a seal structure according to an embodiment of the present invention will be described while explaining the outline of the structure with reference to FIG. FIG. 1 is a left side view of a schematic vertical section showing a schematic structure of a printer as an example of an image forming apparatus. In FIG. 1, the right side is the front side of the printer, and the left side is the back side.

  As shown in FIG. 1, a paper feed cassette 3 that is a paper storage unit is disposed below the inside of the main body 2 of the printer 1. The paper P is stacked and accommodated inside the paper feed cassette 3. A paper feeding device 4 is disposed above the downstream portion of the paper feeding cassette 3 in the paper conveyance direction. The sheet feeding device 4 feeds the sheet P toward the upper right of the sheet feeding cassette 3 in FIG.

  A paper transport path 5, a registration roller 6, an image forming unit 20, and a transfer unit 30 are disposed downstream of the paper feed cassette 3 in the paper transport direction. The paper P sent out from the paper feed cassette 3 reaches the registration roller 6 through the paper transport path 5. The registration roller 6 feeds the paper P to the transfer unit 30 by correcting the oblique feeding of the paper P and timing the toner image formed by the image forming unit 20.

  Image data signals such as characters, graphics, and patterns from an external computer (not shown) are transmitted to the printer 1, and lasers controlled by the optical unit 7 provided above the image forming unit 20 based on the image data. Light L (dashed line in the figure) is irradiated. As a result, the image forming unit 20 forms an electrostatic latent image of the original image on the photosensitive drum 21 that is an image carrier, and the toner image is developed from the electrostatic latent image. The toner image is transferred to the paper P sent in synchronization by the registration roller 6 at a transfer nip portion formed by press contact between the photosensitive drum 21 and the transfer roller 31 of the transfer portion 30.

  A fixing unit 8, a sheet conveyance path 9, and a sheet discharge unit 10 are disposed downstream of the image forming unit 20 and the transfer unit 30 in the sheet conveyance direction. The paper P carrying the unfixed toner image in the transfer unit 30 is sent to the fixing unit 8 and the toner image is fixed by the heat roller. The paper P discharged from the fixing unit 8 is sent upward through the paper conveyance path 9 and is discharged out of the apparatus from a paper discharge unit 10 provided on the upper surface of the main body 2.

  Next, a detailed configuration around the image forming unit 20 of the printer 1 will be described with reference to FIG. 2 in addition to FIG. FIG. 2 is an enlarged left side view of the vertical section showing the periphery of the image forming unit.

  As shown in FIGS. 1 and 2, the image forming unit 20 includes a photosensitive drum 21 that is an image carrier at the center thereof. As shown in FIG. 2, a charging device 40, a developing device 50, a cleaning device 60, and a static elimination device 70 are arranged in order along the rotation direction of the photosensitive drum 21. The transfer unit 30 is provided between the developing device 50 and the cleaning 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 transport direction in the printer 1, that is, the depth direction of the paper surface of FIG. 2, and is arranged with its axis direction horizontal. 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. The photosensitive drum 21 is rotated by a driving device (not shown) so that the peripheral speed thereof is the same as the paper conveyance speed.

  The charging device 40 is a scorotron charging device using a corona discharge charger. Similarly, a corotron charging device using a corona discharge charger or a contact charging device using a roller or a brush may be used. By this charging device 40, the surface of the photosensitive drum 21 is uniformly charged with a predetermined polarity and potential.

  The developing device 50 includes a developing roller 52, a conveying screw 53, and a stirring screw 54 inside the housing 51. The developing roller 52 is provided in the vicinity of the photosensitive drum 21 with a developing method being contact or non-contact. 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. The toner is accommodated in a toner supply container 55 (see FIG. 1) provided above the developing device 50, and is replenished into the housing 51 from above the stirring screw 54 by a conveying means (not shown). The replenished toner is conveyed to the position of the developing roller 52 while being agitated by the agitating screw 54 and the conveying screw 53 in the developing device 50.

  The transfer unit 30 includes a transfer roller 31. The transfer roller 31 is in pressure contact with the photosensitive drum 21 to form a transfer nip portion through which the paper P is inserted. The transfer roller 31 is rotated by a driving device (not shown) so that the peripheral speed thereof is the same as the peripheral speed of the photosensitive drum 21. Further, a transfer bias 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. In FIG. 2, the conveyance path of the paper P is drawn with a two-dot chain line.

  As shown in FIG. 2, the cleaning device 60 is disposed further downstream of the transfer nip portion along the rotation direction of the photosensitive drum 21. The cleaning device 60 includes a cleaning brush 62 that is a rotating member, a cleaning blade 63, and a toner discharge screw 64 inside the housing 61. The cleaning brush 62 and the cleaning blade 63 are brought into pressure contact with the photosensitive drum 21, and after the toner image is transferred to the paper P, the toner and other adhered matters remaining on the surface of the photosensitive drum 21 are removed and cleaned. The toner removed from the surface of the photosensitive drum 21 is once collected in the housing 61 and is discharged by a toner discharge screw 64 to a waste toner collection container (not shown) outside the cleaning device 60.

  The static eliminator 70 includes an LED (light emitting diode) 71. Instead of the LED 71, an EL (electroluminescence) light source, a fluorescent lamp, or the like can be used. 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.

  In the image forming apparatus 1 configured as described above, the seal structure of the present invention is provided to the cleaning brush 62 that is a rotating member of the cleaning device 60 that cleans the surface of the photosensitive drum 21 as described above. The details will be described below.

  A detailed configuration of the seal structure according to the embodiment of the present invention will be described with reference to FIGS. 3 to 6 in addition to FIG. 2. FIG. 3 is a perspective view of the cleaning device, FIG. 4 is a partially sectional front view showing the periphery of the sealing structure of the cleaning brush of the cleaning device, FIG. 5 is a partially enlarged perspective view showing the periphery of the sealing structure of the cleaning brush, and FIG. FIG. 4 and 5 are a partial front view and a partially enlarged perspective view of a vertical section in which a portion of a circle A in FIG. 3 is drawn. 4 and 5, the right side in the drawing is the inside of the cleaning device 60 and the left side is the outside with respect to the wall portion 61 a of the housing 61.

  Both ends of the cleaning brush 62 provided in the cleaning device 60 shown in FIGS. 2 and 3 are supported by the housing 61, and power for rotation is transmitted from one end thereof.

  At both end portions of the cleaning brush 62, the shaft portion 62a is held rotatably with respect to the wall portion 61a of the housing 61 via a bearing 65 as shown in FIGS. A seal structure 80 that prevents leakage of toner to the outside in the axial direction of the cleaning brush 62 is provided inside the bearing 65.

  As shown in FIGS. 4 and 5, the seal structure 80 includes a groove portion 81, a seal member 82, and an elastic member 83.

  The groove portion 81 is provided in the shaft portion 62 a of the cleaning brush 62. The groove portion 81 is a surface of the peripheral surface of the shaft portion 62a, and is provided so as to be cut in a circumferential direction perpendicular to the axial direction. As shown in FIG. 4, the groove 81 also serves as a groove for preventing the adhesive 62c (broken line in the figure) for bonding the brush 62b to the shaft 62a of the cleaning brush 62 to flow outward in the axial direction. Yes.

  The seal member 82 is made of a film-like material and is disposed in the groove portion 81. As shown in FIG. 6, the seal member 82 has a so-called donut shape, and has a circular hole 82 a whose inner diameter is smaller than the outer diameter of the shaft portion 62 a of the cleaning brush 62 and larger than the inner diameter of the groove portion 81. The seal member 82 is provided so that the shaft portion 62a is inserted into the circular hole 82a up to the location of the groove portion 81, and the inner surface of the seal member 82 is brought into pressure contact with the inner wall on the inner side in the axial direction of the groove portion 81. ing. As shown in FIG. 6, the seal member 82 is disposed in the groove 81 by elastically deforming the seal member 82 using a slit 82b provided from the hole 82a to the outer periphery, as shown in FIG. This can be easily implemented by opening the hole 82a.

  The elastic member 83 is made of a foamed material such as a block-like sponge, and is provided between the seal member 82 and the wall portion 61 a of the housing 61. Similar to the seal member 82, the elastic member 83 has a circular hole whose inner diameter is larger than the outer diameter of the shaft portion 62a. The elastic member 83 has a shaft portion 62a inserted into the circular hole and is fixed to the inner surface of the wall portion 61a. The seal member 82 has an axially outer surface affixed to the inner surface of the elastic member 83, but is disposed so as to be in contact with the inner surface of the elastic member 83, preferably in a pressure contact state. If it arrange | positions so that it may touch, it does not need to stick.

  Note that the sealing member 82 may be directly contacted or stuck to the wall portion 61a without using the elastic member 83. In this case, the seal member 82 is disposed such that its inner surface contacts the inner wall inside the groove 81, preferably in a pressure contact state, and its outer surface contacts the inner surface of the wall 61a.

  In this way, in the seal structure 80 provided between the cleaning brush 62 that is a rotating member and the wall portion 61a that holds the cleaning brush 62 so as to be rotatable, the cleaning brush 62 of the cleaning brush 62 is prevented. A groove portion 81 provided in the circumferential direction and a circular hole 82a having an inner diameter smaller than the outer diameter of the shaft portion 62a and larger than the inner diameter of the groove portion 81 are provided on the surface of the shaft portion 62a. A film-like seal member 82 disposed in the groove 81, one surface of the film-like seal member 82 abuts against the inner wall of the groove 81, and the other surface (via the elastic member 83). Since it abuts against the wall portion 61a, the seal member 82 is brought into contact with the cleaning brush 62 with a contact area as small as possible to prevent toner leakage. Bets are possible. Thereby, it is not necessary to bring the seal member 82 into contact with the cleaning brush 62 with a large contact pressure, and the progress of wear can be suppressed. It is also possible to suppress the generation of frictional heat at the seal location. Therefore, it is possible to reliably prevent the toner from leaking to the outside in the axial direction of the cleaning brush 62 without causing troubles such as melting and fixing of the toner with a simpler configuration that can be implemented at low cost. A seal structure 80 can be obtained.

  Further, since the seal member 82 is in pressure contact with the inner wall of the groove 81 of the cleaning brush 62, the seal member 82 and the cleaning brush 62 are in close contact with each other. Thereby, the sealing performance between the sealing member 82 and the cleaning brush 62 is improved. Therefore, it is possible to enhance the effect of preventing the toner leakage to the outside of the cleaning brush 62 in the axial direction.

  Since the block-shaped elastic member 83 having a hole whose inner diameter is larger than the outer diameter of the shaft portion 62a is provided between the seal member 82 and the wall portion 61a, the seal member 82 is sealed by the action of the elastic member 83. The state where the member 82 is always in pressure contact with the cleaning brush 62 can be maintained. Moreover, both contact areas can be made uniform. Accordingly, it is possible to prevent the leakage of toner even in a minute region of the seal portion. As a result, it is possible to further improve the effect of preventing the leakage of the toner to the outside of the cleaning brush 62 in the axial direction.

  Further, in the present invention, the seal structure 80 having the above-described configuration is provided for the cleaning brush 62 that is a rotating member of the cleaning device 60 for cleaning the surface of the photosensitive drum 21 of the printer 1, and thus can be implemented at low cost. With a simpler configuration, it is possible to reliably prevent toner leakage to the outside in the axial direction of the cleaning brush 62 without causing troubles such as melting and fixing of the toner, and to maintain suitable image quality. Can be obtained.

  Further, since the groove 81 is a flow stop groove for the adhesive 62c for bonding the brush 62b to the shaft 62a of the cleaning brush 62, a groove for preventing the adhesive 62c from flowing out in the axial direction. Can be diverted to a seal structure 80 for preventing toner leakage. Therefore, it is possible to save the labor and cost necessary for providing the groove 81 anew because of the seal structure 80. As a result, it is possible to reliably prevent the toner from leaking outward in the axial direction of the cleaning brush 62 with a simple configuration that can be carried out at a lower cost while preventing the occurrence of problems such as toner melting and fixing.

  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 above-described embodiment, the form in which the seal structure of the present invention is applied to the cleaning brush 62 of the cleaning device 60 is described as an example. However, the present invention can also be applied to other rotating members. Other examples of the cleaning brush 62 include the toner discharge screw 64 of the same cleaning device 60, the developing roller 52, the conveying screw 53, and the stirring screw 54 of the developing device 50 as shown in FIG. The seal structure of the present invention can be applied.

  Further, the seal member 82 of the seal structure 80 does not have to have a circular outer shape. If the circular hole 82a having an inner diameter smaller than the outer diameter of the shaft portion 62a and larger than the inner diameter of the groove portion 81 is provided, the outer shape is Other shapes such as a rectangle and an octagon may be used. Similarly, the outer shape of the elastic member 83 may be other than the circular shape.

  The present invention can be used in a seal structure that prevents leakage of powder such as toner.

1 is a left side view of a schematic vertical section showing a schematic structure of a printer as an example of an image forming apparatus provided with a seal structure according to an embodiment of the present invention. FIG. 2 is an enlarged left side view of a vertical section showing the periphery of an image forming unit of the printer of FIG. 1. FIG. 3 is a perspective view of the cleaning device shown in FIG. 2. FIG. 4 is a partial front view of a vertical section showing the periphery of the seal structure of the cleaning brush of FIG. 3. FIG. 4 is a partially enlarged perspective view showing the periphery of the seal structure of the cleaning brush in FIG. 3. It is a perspective view of the sealing member shown in FIG.

Explanation of symbols

1 Printer (image forming device)
20 Image forming unit 21 Photosensitive drum (image carrier)
60 Cleaning Device 61 Housing 61a Wall 62 Cleaning Brush (Rotating Member)
62a Shaft portion 62b Brush portion 62c Adhesive 80 Seal structure 81 Groove portion 82 Seal member 82a Hole 83 Elastic member

Claims (5)

In a seal structure provided between the rotating member and the wall portion that holds and rotates the rotating member, and prevents leakage of toner,
A groove portion provided in the circumferential direction and a circular hole having an inner diameter smaller than the outer diameter of the shaft portion and larger than the inner diameter of the groove portion are provided on the surface of the shaft portion of the rotating member, and the groove portion is passed through the shaft portion. And a film-like seal member disposed inside the film-like seal member, wherein one surface of the film-like seal member is in contact with the inner wall of the groove and the other surface is in contact with the wall. .   The seal structure according to claim 1, wherein the seal member is in pressure contact with the inner wall of the groove of the rotating member.   The block-shaped elastic member provided with the hole whose inner diameter is larger than the outer diameter of the said shaft part between the said sealing member and the said wall part is provided. Seal structure.   An image forming apparatus comprising the sealing structure according to any one of claims 1 to 3 for a cleaning brush that is a rotating member of a cleaning device that cleans the surface of an image carrier.   The image forming apparatus according to claim 4, wherein the groove portion is an adhesive flow stop groove for bonding the brush portion to the shaft portion of the cleaning brush.

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