Patent Grant
9098060
1. Field of the Invention
The present invention relates to a cleaning device, a process cartridge, and an image forming apparatus.
2. Description of the Related Art
In an electrophotographic image forming apparatus, a cleaning blade method using a cleaning unit has been known for removing developer remaining on an image bearing member (a member to be cleaned) after a developer image formed on the image bearing member has been transferred onto a recording medium to repeatedly use the image bearing member.
The cleaning blade method is a method for removing developer from a surface of the image bearing member by contacting a blade having elasticity with the surface of the image bearing member at a predetermined pressure.
In United States Patent Publication Application No. 5470635, a cleaning member has a configuration in which a blade is attached to a tip end of a sheet metal serving as a supporting member by shape forming. The cleaning member is fixed by attaching the sheet metal to a frame member with a screw or the like, to bring the cleaning member into contact with a surface of an image bearing member at a predetermined pressure.
An image forming apparatus such as a printer tends to be reduced in size, increased in speed, and enhanced in image quality as it spreads. With the reduction of the image forming apparatus in size, the size of an image bearing member is to be reduced. The image bearing member rotates fast when the image forming apparatus is to be increased in speed. More specifically, a blade, which contacts a surface of the image bearing member, slides on the surface of the image bearing member repeatedly at high speed. The temperature of the blade itself rises, so that the hardness of the blade is lowered. As a result, the friction force between the surface of the image bearing member and the blade rises. Thus, a driving torque for driving the image bearing member may increase, and the blade may warp. Further, developer with a spherical shape may have recently been used to enhance the image quality. In this case, a contact pressure of the blade on the image bearing member needs to be increased to remove the developer from the surface of the image bearing member, which is one of factors for confounding the above-mentioned problem.
The present invention is directed to a technique for improving stability of a contact pressure of a blade portion on a member to be cleaned.
According to an aspect of the present invention, a cleaning device for an image forming apparatus includes (i) a frame member, (ii) a cleaning member for removing a developer from a surface of a member to be cleaned. The cleaning member includes a blade portion configure to come into contact with the member to be cleaned in a direction counter to a moving direction of the member to be cleaned, and a flexible plate-like supporting member configured to support the blade portion, the supporting member including one end portion, in which the blade portion is provided, the other end portion, which has a portion to be fixed to the frame member, a bent portion, which is positioned between the one end portion and the other end portion and positioned outwardly away from the surface of the member to be cleaned with respect to a line segment connecting the portion to be fixed and a contact portion, in which the blade portion comes into contact with the member to be cleaned, and a side plate portion projecting from a side end of the one end portion, wherein the portion to be fixed is arranged on the downstream side of the moving direction of the member to be cleaned to the contact portion, (iii) a storage member, which includes the frame member, configured to store the developer removed by the cleaning member, and (iv) a sealing member, which is provided between the cleaning member and the frame member, configured to prevent the developer from leaking from the storage member and fixed to one of the side plate portion and the frame member.
According to another aspect of the present invention, a process cartridge attachable to and detachable from an image forming apparatus, the process cartridge includes (i) a photosensitive member, (ii) a frame member, (iii) a cleaning member for removing a developer from a surface of the photosensitive member. The cleaning member includes a blade portion configured to come into contact with the photosensitive member in a direction counter to a moving direction of the photosensitive member, and a flexible plate-like supporting member configured to support the blade portion, the supporting member including one end portion, in which the blade portion is provided, the other end portion, which has a portion to be fixed to the frame member, a bent portion, which is positioned between the one end portion and the other end portion and positioned outwardly away from the surface of the photosensitive member with respect to a line segment connecting the portion to be fixed and a contact portion, in which the blade portion comes into contact with the photosensitive member, and a side plate portion projecting from a side end of the one end portion, wherein the portion to be fixed is arranged on the downstream side of the moving direction of the photosensitive member to the contact portion, (iv) a storage chamber, which includes the frame member, configured to store the developer removed by the cleaning member, and (v) a sealing member, which is provided between the cleaning member and the frame member, configured to prevent the developer from leaking from the storage chamber and fixed to one of the side plate portion and the frame member.
According to yet another aspect of the present invention, an image forming apparatus for forming an image on a recording medium, the image forming apparatus includes (i) a member to be cleaned, (ii) a frame member, (iii) a cleaning member for removing a developer from a surface of a member to be cleaned. The cleaning member includes a blade portion configured to come into contact with the member to be cleaned in a direction counter to a moving direction of the member to be cleaned, and a flexible plate-like supporting member having configured to support the blade portion, the supporting member including one end portion, in which the blade portion is provided, the other end portion, which has a portion to be fixed to the frame member, a bent portion, which is positioned between the one end portion and the other end portion and positioned outwardly away from the surface of the member to be cleaned with respect to a line segment connecting the portion to be fixed and a contact portion, in which the blade portion comes into contact with the member to be cleaned, and a side plate portion projecting from a side end of the one end portion, wherein the portion to be fixed is arranged on the downstream side of the moving direction of the member to be cleaned to the contact portion, (iv) a storage chamber, which includes the frame member, configured to store the developer removed by the cleaning member, and (v) a sealing member, which is provided between the cleaning member and the frame member, configured to prevent the developer from leaking from the storage chamber and fixed to one of the side plate portion and the frame member.
Further features of the present invention will become apparent from the following description of exemplary embodiments with reference to the attached drawings.
Various exemplary embodiments, features, and aspects of the invention will be described in detail below with reference to the drawings.
The size, the material, and the shape of each of components and their relative arrangement described in the following exemplary embodiments may be changed, as needed, depending on a configuration of an apparatus to which the present invention is applied and various conditions, and do not intend to restrict the scope of the present invention to the following exemplary embodiments.
An image forming apparatus to which the present invention is applicable includes an electrophotographic copying machine, a laser beam printer, a light emitting diode (LED) printer, and a facsimile apparatus. A process cartridge refers to the one that is integrally formed at least including an image bearing member and a cleaning device as a cartridge and is attachable and detachable to and from the image forming apparatus.
An example of an image forming apparatus according to a first exemplary embodiment will be described below.
A drum type photosensitive member (hereinafter referred to as a photosensitive drum) 1 serving as an image bearing member (a member to be cleaned) is disposed substantially at the center of an image forming apparatus body (hereinafter referred to as an apparatus body) M. The photosensitive drum 1 has an organic photo conductor (OPC) photosensitive layer formed on an outer peripheral surface of its conductive drum base made of aluminum, and is driven to rotate around a rotation axis (axis) at a predetermined process speed (peripheral speed) of 200 mm/s in a direction of an arrow R1 illustrated in
A surface (peripheral surface) of the photosensitive drum 1 is uniformly charged to a predetermined polarity and potential by a charging roller 2 serving as a charging unit. The surface of the photosensitive drum 1 after the charging is subjected to scanning exposure with a laser beam. The laser beam is output from a laser beam scanner 3 serving as an exposure unit and modulated to correspond to a time series electric digital pixel signal of target image information, and an electrostatic latent image corresponding to the target image information is formed on the surface of the photosensitive drum 1. The electrostatic latent image is developed as a toner image (a developer image or a developed image) when supplied with toner 4 serving as a developer by a development device 5 serving as a development unit.
On the other hand, a recording material (recording medium) 6 is fed by a feeding roller, and is sent to a transfer nip portion between the photosensitive drum 1 and a transfer roller 8 so as to be synchronized with the toner image formed onto the photosensitive drum 1. With the arrangement, the toner image is transferred onto a surface of the recording material 6. A transfer bias for transfer is applied to the transfer roller 8 from a transfer bias apply power source during transfer.
The recording material 6, on which the toner image has been transferred, is separated from the surface of the photosensitive drum 1 and is conveyed to a fixing device 10 serving as a fixing unit. In the fixing device 10, the recording material 6 is heated and pressurized so that the toner image is fixed to its surface.
On the other hand, after the toner image has been transferred onto the recording material 6, the toner 4 remaining on the surface of the photosensitive drum 1 without being transferred onto the recording material 6 is removed by a cleaning device 11 serving as a cleaning unit, and the photosensitive drum 1 is prepared for the subsequent image formation.
In the image forming apparatus according to the present exemplary embodiment, a process cartridge (a process unit or a cartridge) N includes four process devices, which are the photosensitive drum 1, the charging roller 2, the development device 5, and the cleaning device 11, incorporated into its cartridge container. The process cartridge N is configured to be attachable to and detachable from the apparatus body M.
The cleaning device 11 includes the cleaning blade 12, sealing members 13 and 15, and a housing 14. In the cleaning device 11, the cleaning blade 12 and the housing 14 form a waste toner chamber (storage chamber) D for storing toner removed from the surface of the photosensitive drum 1 by the cleaning blade 12. The cleaning device 11 is provided with a sealing structure for sealing between the cleaning blade 12 and the housing 14 to prevent the toner from leaking from the waste toner chamber D. The sealing structure includes the sealing members 13 and 15. In
The cleaning blade 12, which is a characteristic component of the present exemplary embodiment, includes a plate-shaped supporting member 12b having flexibility, and a blade portion 12a formed of a rubber member at one end (a tip end or a free end) of the supporting member 12b. The blade portion 12a comes into contact with the photosensitive drum 1 in a counter direction with respect to a movement direction of the photosensitive drum 1 (a direction of the arrow R1 illustrated in
The supporting member 12b is subjected to bending work so that a bent portion (folded portion) C is uniformly formed along a rotation axis direction of the photosensitive drum 1 between the blade portion 12a and the fixed portion A.
In the present exemplary embodiment, a portion of the supporting member 12b from the bent portion C to the blade portion 12a on the side of the tip end is one end portion L1. A portion of the supporting member 12b from the fixed portion A to the bent portion C is the other end portion L2, as illustrated in
As illustrated in
With such a configuration, the one end portion L1 receives a force from the blade portion 12a, to elastically deform the other end portion L2. If the blade portion 12a is pushed in due to an increase in friction with the photosensitive drum 1 when the photosensitive drum 1 moves from its stationary state, the bent portion C is movable in a direction away from the surface of the photosensitive drum 1.
A stainless steel (SUS) plate having a thickness of 0.2 mm is used for the supporting member 12b. In addition, a member having a spring characteristic (plate-shaped spring member), for example, a phosphor bronze plate can be used as a blade material.
As the rubber member forming the blade portion 12a, urethane rubber having a Japan Industrial Standards (JIS) A hardness of 70 degrees is used. The shape of the blade portion 12a is as illustrated in
As described above, the other end portion L2 has flexibility with respect to the displacement of the one end portion L1 in the direction of the arrow a illustrated in
As a general sealing configuration (sealing structure), a sealing configuration for preventing leakage of waste toner by pressing a sealing member 103 against an end of a cleaning blade 12 (an end of one end portion L1) is illustrated in
In such a sealing configuration, the one end portion L1 is displaced in a direction of an arrow a and a direction of an arrow b illustrated in
The one end portion L1 is pressed against the sealing member 103 when displaced. Thus, the one end portion L1 receives a force by elasticity of the sealing member 103 in a direction opposite to the displacement of the one end portion L1. This raises concerns that a deformation operation of the one end portion L1 is prevented, the movement of the blade portion 12a away from the photosensitive drum 1 is obstructed, and an effect of suppressing increases in an contact pressure and a friction force is reduced.
The cleaning device 11 according to the present exemplary embodiment has a further characteristic configuration, as illustrated in
In the present exemplary embodiment, the cleaning blade 12 includes side plate portions L3 formed by using each end in a longitudinal direction of the one end portion L1 as a folded projection. The side plate portions L3 are respectively provided at both ends in the longitudinal direction of the one end portion L1 (side ends of the one end portion L1) to project toward the housing 14 (toward a frame member) from the one end portion L1. The longitudinal direction is a direction perpendicular to the movement direction of the photosensitive drum 1, i.e., a rotation axis direction of the photosensitive drum 1, on the surface of the photosensitive drum 1.
While the supporting member 12b is formed by folding a metal plate spring of one member in the present exemplary embodiment, the present invention is not limited to this. The supporting member 12b may be formed of a plurality of members (e.g., a combination of flat plate-shaped members).
In the present exemplary embodiment, the sealing member 13 having a sliding surface 13a, which slidably contacts the side plate portion L3, is further provided. In the present exemplary embodiment, the side plate portion L3 and the blade portion 12a are provided flush with each other (at substantially the same positions in the longitudinal direction) so that the sealing member 13 slidably contacts each of the ends in the longitudinal direction of the side plate portion L3 and the blade portion 12a.
The side plate portion L3 and the blade portion 12a may not be arranged flush with each other as long as the ends in the longitudinal direction of the side plate portion L3 and the blade portion 12a can be sealed. The configuration is not limited to the case in which the sealing member 13 performs sealing by slidably contacting both the side plate portion L3 and the blade portion 12a. The sealing member 13 may slidably contact only the side plate portion L3, and another sealing member may slidably contact the blade portion 12a.
The sealing member 13 is fixed to the housing 14, and the sealing member 13 and the side plate portion L3 are disposed to contact each other outside of the housing 14 and overlap each other when viewed from the longitudinal direction. As illustrated in
The cleaning blade 12 is thus configured so that the sealing member 13 slidably contacts the side plate portion L3 when the one end portion L1 is displaced. Thus, a gap is not formed between the one end portion L1 and the sealing member 13 even if the one end portion L1 is displaced. Therefore, the occurrence of leakage of waste toner can be suppressed.
In the configuration according to the present exemplary embodiment, even if the one end portion L1 is displaced in the directions of the arrow a and the arrow b as the photosensitive drum 1 rotates, the one end portion L1 does not receive a force by elasticity of the sealing member 13 in a direction opposite to the displacement of the one end portion L1, like in a form illustrated in
As described above, according to the present exemplary embodiment, the sealing performance can be improved while the further effect of stabilizing the contact pressure of the blade portion 12a on the photosensitive drum 1 can be obtained by suppressing the contact pressure and the friction force of the blade portion 12a against the photosensitive drum 1 to a predetermined value or less.
A second exemplary embodiment is described below. In the present exemplary embodiment, different components from those in the first exemplary embodiment will be described, and description of similar components to those in the first exemplary embodiment is not repeated.
While the sealing member 13 is arranged outside the side plate portion L3 (outside the waste toner chamber D) in the first exemplary embodiment, a sealing member 13 is arranged inside a side plate portion L3 (inside a waste toner chamber D) in the present exemplary embodiment.
In the present exemplary embodiment, a housing 14 can be formed by making the width thereof in a longitudinal direction narrower than that in the first exemplary embodiment. Therefore, the housing 14 and the cleaning device 11 can be miniaturized.
Also in the configuration according to the present exemplary embodiment, if one end portion L1 is displaced, the sealing member 13 slidably contacts the side plate portion L3. Even if the one end portion L1 is displaced, therefore, a gap is not formed between the one end portion L1 and the sealing member 13. Thus, the occurrence of leakage of waste toner can be suppressed.
In the present exemplary embodiment, the sealing member 13 is positioned inside the side plate portion L3. Thus, the sealing member 13 and a blade portion 12a contact to overlap each other in a radial direction with respect to a rotation axis of a photosensitive drum 1, as illustrated in
Also in the present exemplary embodiment, the sealing member 13 may slidably contact only the side plate portion L3, to configure a sealing structure by providing another sealing member between the sealing member 13 and the blade portion 12a and making the other sealing member slidably contact the blade portion 12a.
As described above, in the present exemplary embodiment, a similar effect to that in the above-mentioned first exemplary embodiment can also be obtained. In addition thereto, the reduction in size of the housing 14 and the cleaning device 11 can also be realized in the present exemplary embodiment.
A third exemplary embodiment will be described below. In the present exemplary embodiment, different components from those in the first and second exemplary embodiments will be described, and description of similar components to those in the first and second exemplary embodiments is not repeated.
In the present exemplary embodiment, a sealing member 13 has a slit (groove) 13b into which a side plate portion L3 is inserted.
While the sealing member 13 contacts only one surface of the side plate portion L3, as illustrated in
In the present exemplary embodiment, a slit 13b is sufficiently deep so that the side plate portion L3 does not come into contact with the bottom of the slit 13b even if the side plate portion L3 is displaced in a direction of an arrow a. Consequently, even if one end portion L1 is displaced as a photosensitive drum 1 rotates, the side plate portion L3 is not pressed against the bottom of the slit 13b. Therefore, the displacement of the one end portion L1 is prevented from being obstructed by arranging the side plate portion L3 in the slit 13b.
Also in the present exemplary embodiment, the sealing member 13 is made to contact the side plate portion L3 and a blade portion 12a to seal an end in a longitudinal direction of the blade portion 12a, like in the second exemplary embodiment. The sealing of the end in the longitudinal direction of the blade portion 12a has been described in the second exemplary embodiment.
As described above, according to the present exemplary embodiment, a similar effect to that in the first exemplary embodiment can also be obtained. In the present exemplary embodiment, the sealing performance can be improved more than that in the first exemplary embodiment.
While the sealing member 13 is fixed to the housing 14 in the above-mentioned first to third exemplary embodiments, the present invention is not limited to this. The sealing member 13 may be fixed to the side plate portion L3 and slidably contact the housing 14. More specifically, the sealing member 13 may be fixed to either one of the side plate portion L3 and the housing 14 and slidably contact the other. This also realizes a sealing structure for sealing between the cleaning blade 12 and the housing 14.
The present invention is not limited to the above-mentioned image forming apparatus illustrated in
According to the present invention, a contact pressure of a blade portion on a member to be cleaned can be more stabilized.
While the present invention has been described with reference to exemplary embodiments, it is to be understood that the invention is not limited to the disclosed exemplary embodiments. The scope of the following claims is to be accorded the broadest interpretation so as to encompass all such modifications and equivalent structures and functions.
This application claims the benefit of Japanese Patent Application No. 2013-039528 filed Feb. 28, 2013, which is hereby incorporated by reference herein in its entirety.
| Number | Date | Country | Kind |
|---|---|---|---|
| 2013-039528 | Feb 2013 | JP | national |
| Number | Name | Date | Kind |
|---|---|---|---|
| 5470635 | Shirai | Nov 1995 | A |
| 5602623 | Nishibata et al. | Feb 1997 | A |
| 5991568 | Ziegelmuller et al. | Nov 1999 | A |
| Number | Date | Country | |
|---|---|---|---|
| 20140241772 A1 | Aug 2014 | US |
