Charging device, process cartridge, image forming apparatus, and sheet-like member

Abstract

To sufficiently and stably remove a discharge product attached to a surface of a charging roller.SOLUTION: A charging device is provided with a charging roller 4 that rotates in a predetermined rotation direction. The charging device is further provided with a sheet-like member 30 that is formed of a material containing a polar absorbent K at least in a portion in contact with the charging roller 4, and that is elastically deformed in a bow shape to be in contact with the charging roller 4.SELECTED DRAWING: Figure 3

Description

[Technical field]

[0001] The present invention relates to a charging device that charges the surface of an image carrier such as a photosensitive drum, a process cartridge and an image forming apparatus that include the charging device, and a sheet-like member that contacts a rotating body such as a charging roller. [Background technology]

[0002] Conventionally, in image forming devices such as copiers and printers, there has been widely known a technique for removing discharge products adhering to the surface of a charging roller that charges a photosensitive drum (image carrier) (see, for example, Patent Document 1). More specifically, in the charging device described in Patent Document 1 and the like, a brush-like or box-like discharge product removal member containing a polar adsorbent is disposed so as to be in sliding contact with the surface of the charging roller, and the discharge product removal member removes the discharge products adhering to the surface of the charging roller. Summary of the Invention [Problem to be solved by the invention]

[0003] In the charging device of Patent Document 1, a brush-like or box-like discharge product removal member containing a polar adsorbent is arranged in sliding contact with the surface of the charging roller, and it is expected that the discharge products adhering to the surface of the charging roller are removed, making it less likely that abnormal images such as uneven charging will occur. However, it is difficult to stably set the contact pressure of the discharge product removal member that comes into contact with the charging roller within an appropriate range, and there is a possibility that the discharge products adhering to the surface of the charging roller cannot be sufficiently removed.

[0004] The present invention has been made to solve the above-mentioned problems, and aims to provide a charging device, a process cartridge, an image forming apparatus, and a sheet-like member that are capable of sufficiently and stably removing discharge products adhered to the surface of a charging roller. [Means for solving the problem]

[0005] The charging device of the present invention comprises a charging roller that rotates in a predetermined rotational direction, and a sheet-like member, at least the portion of which that contacts the charging roller is formed from a material containing a polar adsorbent, and which contacts the charging roller in a state in which it is elastically deformed into a bow shape. Effect of the Invention

[0006] According to the present invention, it is possible to provide a charging device, a process cartridge, an image forming apparatus, and a sheet-like member that are capable of sufficiently and stably removing discharge products adhering to the surface of a charging roller. [Brief description of the drawings]

[0007] [Figure 1] 1 is an overall configuration diagram showing an image forming apparatus according to an embodiment of the present invention; [Diagram 2] FIG. 2 is a diagram illustrating a configuration of a process cartridge. [Diagram 3] FIG. [Figure 4] 1A is a perspective view showing the tip portion of a sheet-shaped member, and FIG. 1B is a cross-sectional view showing the tip portion of the sheet-shaped member. [Diagram 5] FIG. 11 is a cross-sectional view showing a sheet-like member as a first modified example. [Figure 6] 13A to 13C are diagrams illustrating the operation of a charging device according to a second modified example. [Figure 7] 13A to 13C are diagrams illustrating the operation of a charging device according to a third modified example. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0008] Hereinafter, the embodiments of the present invention will be described in detail with reference to the drawings. In each drawing, the same or corresponding parts are denoted by the same reference numerals, and the duplicated description will be appropriately simplified or omitted.

[0009] First, the overall configuration and operation of an image forming apparatus 100 will be described with reference to FIG. In FIG. 1, reference numeral 100 denotes a printer as an image forming apparatus, 1 denotes a photosensitive drum on whose surface a toner image is formed, 6 denotes a process cartridge in which the photosensitive drum 1, a charging device 3 (charging roller 4), a developing device 5, and a cleaning device 2 are integrated, and 7 denotes an exposure section (writing section) that irradiates the photosensitive drum 1 with exposure light L based on image information input from an input device such as a personal computer. Also, reference numeral 9 denotes a transfer roller that transfers the toner image carried on the surface of the photosensitive drum 1 onto a sheet P transported to a transfer nip portion (transfer position), and reference numeral 12 denotes a paper feed device (paper feed cassette) in which sheets P such as paper are stored. Also, reference numeral 16 denotes a registration roller (timing roller) that conveys the sheet P toward a transfer nip portion where the photosensitive drum 1 and the transfer roller 9 abut against each other, and 20 denotes a fixing device that fixes an unfixed image on the sheet P.

[0010] Here, a charging device 3 (charging roller 4), a developing device 5, a cleaning device 2, etc. are arranged around the photosensitive drum 1. These members (the photosensitive drum 1, the charging device 3, the developing device 5, and the cleaning device 2) are integrated as a process cartridge 6, which is installed detachably (replaceably) in the image forming apparatus main body 100. When the process cartridge 6 reaches a predetermined replacement cycle or when maintenance is performed, it is removed from the image forming apparatus main body 100 and replaced with a new one (or one that has been maintained).

[0011] With reference to FIG. 1, the operation of image forming apparatus 100 during normal image formation will be described. First, when image information is sent from an input device such as a personal computer to the exposure unit 7 of the image forming apparatus 100, the exposure unit 7 emits exposure light L (laser light) based on the image information toward the surface of the photosensitive drum 1. Meanwhile, the photoconductor drum 1 receives drive from a drive motor installed in the image forming apparatus main body 100 and rotates in the direction of the arrow (clockwise). Then, first, the surface of the photoconductor drum 1 is uniformly charged at a position facing the charging roller 4 (charging process). In this way, a charging potential (about -900V) is formed on the photoconductor drum 1. Then, the charged surface of the photoconductor drum 1 reaches a position irradiated with the exposure light L. Then, the potential of the portion irradiated with the exposure light L becomes a latent image potential (about 0 to -100V), and an electrostatic latent image is formed on the surface of the photoconductor drum 1 (exposure process).

[0012] Thereafter, the surface of the photoconductor drum 1 on which the electrostatic latent image has been formed reaches a position facing the developing device 5. Then, toner is supplied from the developing device 5 onto the photoconductor drum 1, and the latent image on the photoconductor drum 1 is developed to form a toner image (this is the developing process). Thereafter, the surface of the photoconductor drum 1 after the development process reaches a transfer nip portion (transfer position) with the transfer roller 9. Then, at the transfer nip portion with the transfer roller 9, a transfer bias (a bias with a polarity different from that of the toner) is applied from a power supply unit to the transfer roller 9, so that the toner image formed on the photoconductor drum 1 is transferred onto the sheet P conveyed by the registration roller 16 (this is the transfer process).

[0013] Then, after the transfer process, the surface of the photoconductor drum 1 reaches a position facing the cleaning device 2. At this position, untransferred toner remaining on the photoconductor drum 1 is mechanically removed by a cleaning blade 2a (see FIG. 2) and collected in the cleaning device 2 (cleaning process). Thus, a series of image forming processes on the photosensitive drum 1 is completed.

[0014] On the other hand, the sheet P conveyed to the transfer nip portion between the photosensitive drum 1 and the transfer roller 9 operates as follows. First, the uppermost sheet of the sheets P stored in the sheet feeder 12 is fed by the sheet feed roller 15 toward the conveyance path. Thereafter, the sheet P reaches the position of the registration rollers 16. Then, the sheet P that has reached the position of the registration rollers 16 is transported toward the transfer nip portion (the contact position between the transfer roller 9 and the photosensitive drum 1) in time for alignment with the image formed on the photosensitive drum 1.

[0015] After the transfer process, the sheet P passes through the transfer nip portion (transfer roller 9) and then travels through a transport path to reach the fixing device 20. The sheet P that has reached the fixing device 20 is fed between the fixing roller 21 and the pressure roller 22, and the image is fixed by the heat received from the fixing roller 21 and the pressure received from both members 21 and 22. The sheet P with the fixed image is sent out from between the fixing roller 21 and the pressure roller 22 (the fixing nip portion), and then discharged from the image forming apparatus main body 100 and placed on the paper discharge tray. In this way, a series of image forming processes is completed.

[0016] Next, the process cartridge 6 in the image forming apparatus will be described in more detail with reference to FIG. As shown in FIG. 2, the process cartridge 6 is composed of a photosensitive drum 1 as an image carrier, a charging device 3 (charging roller 4), a developing device 5, a cleaning device 2, and the like. The photosensitive drum 1 serving as an image carrier is a negatively charged organic photosensitive member, and receives a driving force from a driving motor provided on the apparatus main body 100 side and is driven to rotate in the clockwise direction in FIG.

[0017] The charging device 3 is composed of a charging roller 4, a sheet-like member 30, and the like. The charging roller 4 is an elastic roller in which a medium resistance foamed urethane layer is formed on a core metal, the foamed urethane layer being made of urethane resin, carbon black as conductive particles, a sulfurizing agent, a foaming agent, etc. The material for the medium resistance layer of the charging roller 4 may be a rubber material in which conductive materials such as carbon black or metal oxides are dispersed in urethane, ethylene-propylene-diene polyethylene (EPDM), butadiene acrylonitrile rubber (NBR), silicone rubber, or isoprene rubber, etc., to adjust the resistance, or a foamed version of these may also be used. Here, in this embodiment, the charging roller 4 is configured to come into contact with the photosensitive drum 1, but it may also be configured so that the charging roller 4 does not come into contact with the photosensitive drum 1, with a gap of about several tens of μm therebetween. The charging device 3 is provided with a sheet-like member 30 for removing discharge products that adhere to the surface of the charging roller 4 by performing a charging process involving discharge. This will be described in detail later with reference to Figures 3 and 4, etc.

[0018] The developing device 5 is disposed such that a developing roller 51 as a developer carrier contacts the photosensitive drum 1 with a predetermined pressure, and a developing area is formed between the two members 1, 51 (developing nip). The developing device 5 contains toner T as a developer (a non-magnetic or magnetic one-component developer). The developing device 5 develops the electrostatic latent image formed on the photosensitive drum 1 (forms a toner image). The cleaning device 2 is provided with a cleaning blade 2a that comes into sliding contact with the photosensitive drum 1, and mechanically removes and collects untransferred toner on the photosensitive drum 1. The cleaning blade 2a is a substantially plate-shaped member made of an elastic material such as urethane rubber, and comes into contact with the photosensitive drum 1 with a predetermined contact pressure and contact angle.

[0019] 2, the developing device 5 in this embodiment is a contact single-component developing device, and is made up of a developing roller 51 as a developer carrier, a supply roller 52 as a developer supply member, a doctor blade 53 as a developer regulating member, etc. Toner T is stored inside the developing device 5. The developing roller 51 (developer carrier) is disposed so as to come into contact with the photosensitive drum 1, and rotates in a predetermined direction (counterclockwise in FIG. 2) while carrying toner, supplying the toner to the electrostatic latent image formed on the photosensitive drum 1. The developing roller 51 may be one having a roller portion made of an elastic material on a rotating shaft portion (core metal) made of a conductive metal material such as stainless steel. The supply roller 52 (developer supply member) is disposed so as to be in sliding contact with the developing roller 51, and supplies toner to the developing roller 51. The supply roller 52 is made of a core metal and a conductive polyurethane foam layer (having an electrical resistance of 10 3 ~10 14 The supply roller 52 also has a function of removing, from the developing roller 51, the toner on the developing roller 51 that has not been used in the developing process in the developing area with the photosensitive drum 1. Doctor blade 53 (developer regulating member) is arranged so that its tip contacts the outer circumferential surface of developing roller 51 at a predetermined angle with a pressure of approximately 10 to 100 N / m, and regulates the amount of toner carried by developing roller 51. Here, a predetermined voltage is applied from a power supply unit to the developing roller 51, the supply roller 52, and the doctor blade 53, promoting electrostatic movement of the toner on the developing roller 51. In this embodiment, an alternating voltage (a square wave with an AC frequency of about 500 to 1000 Hz, a peak-to-peak voltage of about 500 to 3000 V, and an application time duty of about 30 to 70%) is applied to the developing roller 51 so that the toner moves back and forth between the developing roller 51 and the photosensitive drum 1 in the development area.

[0020] The developing device 5 configured as above operates as follows during a normal developing process. First, a portion of the toner contained in the developing device 5 is supplied to and carried by the supply roller 52. The toner carried by the supply roller 52 is frictionally charged at the pressure contact portion (contact position) with the developing roller 51, and then moves onto the developing roller 51 and is carried there. The toner carried on the developing roller 51 is then thinned, uniformed, and frictionally charged at the contact position with the doctor blade 53, and then reaches a position facing the photoconductor drum 1 (development area). At this position, the toner is attracted to the latent image formed on the photoconductor drum 1 by the electric field (development electric field) formed in the development area.

[0021] The characteristic configuration and operation of the charging device 3 (process cartridge 6) in this embodiment will be described in detail below. 3 and other figures, the charging device 3 is provided with a charging roller 4 and a sheet-like member 30 as charging members. The charging roller 4 is rotated in a predetermined direction (the direction of the arrow in FIG. 3, ie, clockwise) by being driven by a driving mechanism (not shown). Therefore, the charging roller 4 comes into contact with the photosensitive drum 1 (image carrier) in the counter direction, which rotates in the direction of the arrow in FIG. 3 (clockwise direction).

[0022] 3, 4, etc., the sheet-like member 30 is a member that comes into contact with the charging roller 4 as a rotating body while being elastically deformed into a bow shape. Specifically, the sheet-like member 30 is supported at one end by a support member 31 (holder) so that the side of the portion that contacts the charging roller 4 is the free end side. The support member 31 is a plate-like member (sheet metal) made of a metal material or the like, and is held by a case of the charging device 3 (process cartridge 6). The base portion (fixed end) of the sheet-like member 30 is attached to the support member 31 with double-sided tape, adhesive, or the like. Such sheet-like member 30 may be a substantially rectangular member having a thickness of 1 mm or less and made of urethane rubber, mylar, thin metal plate, or the like.

[0023] In this way, the sheet-like member 30 can also be said to be a bendable member. Here, "curvable" refers to a state in which the sheet-like member 30 deforms when it comes into contact with the charging roller 4 and can apply pressure to the charging roller 4 by the resilience of the sheet-like member 30 itself. Specifically, the degree of curvature of the sheet-like member 30 may be within a range in which it can follow the surface of the charging roller 4 without interfering with the rotation of the charging roller 4.

[0024] More specifically, in this embodiment, the sheet-like member 30 is disposed so that its leading end abuts against the charging roller 4 in the direction of rotation of the charging roller 4 . That is, the sheet-like member 30 is disposed so as to contact the charging roller 4 in a trailing direction rather than in a counter direction. Also, the sheet-like member 30 is disposed so as to make surface contact with the charging roller 4 rather than in line or point contact with the charging roller 4.

[0025] In this embodiment, the sheet-like member 30 is set so that the contact pressure (contact pressure) with the charging roller 4 is about 6 to 12 N / m, and the contact width (width in the rotational direction of surface contact) is about 10 to 2000 mμ. The contact pressure of the sheet-like member 30 against the charging roller 4 is determined by the balance between the amount of deformation (deflection) of the sheet-like member 30 itself and the repulsive force from the charging roller 4, so it does not change significantly and is stable. When the printing operation is not performed and the charging roller 4 is stopped from rotating, the sheet-like member 30 is in a curved state with its belly portion in contact with the charging roller 4. Then, when the printing operation is performed and the charging roller 4 rotates, the sheet-like member 30 comes into sliding contact with the charging roller 4 while maintaining the curved state.

[0026] 3, 4, etc., the sheet-like member 30 is made of a material containing a polar adsorbent K at least in a portion that contacts the charging roller 4. In detail, in the present embodiment, the sheet-like member 30 has a surface (the surface that comes into contact with the charging roller 4) on which a polar adsorbent K is sprayed in the range M in Figures 3 and 4 (a range of about 20 mm from the tip, which is the free end, toward the base portion). In other words, in this embodiment, at least the portion of the sheet-like member 30 that abuts against the rotating body is formed from a material containing polar adsorbent K, and is configured to be able to abut against the rotating body while being elastically deformed into a bow shape.

[0027] Here, the polar adsorbent K is a material that electrostatically adsorbs discharge products that have adhered to the outer peripheral surface of the charging roller 4 and become polar (or discharge products that have dissolved in water and become ionized), and removes the discharge products from the outer peripheral surface of the charging roller 4. Specifically, the polar adsorbent K can be at least one of zeolite, silica alumina-based adsorbents, silica gel, alumina gel, activated alumina, and activated clay. The discharge products are nitrogen oxides generated by discharge, which combine with substances in the air to become nitric oxides. If a large amount of discharge products adheres to the charging roller 4, it becomes impossible to uniformly charge the photoconductor drum 1 during the charging process. This makes it easier for abnormal images to occur, such as uneven charging or poor charging.

[0028] In this embodiment, the sheet-like member 30 contains polar adsorbent K at least in the portion that contacts the charging roller 4, and therefore functions as a discharge product removal member that removes discharge products adhering to the surface of the charging roller 4. Furthermore, compared to a brush-like or box-like member, the sheet-like member 30 in this embodiment can apply pressure to the charging roller 4 by the repulsive elasticity of the sheet-like member 30 itself, and therefore the contact pressure with the charging roller 4 can be stably set within an appropriate range. Therefore, the discharge products adhering to the surface of the charging roller 4 can be sufficiently and stably removed, and the occurrence of abnormal images such as uneven charging and charging failure can be sufficiently and stably reduced. In addition, as described above, in this embodiment, the bendable sheet-like member 30 that comes into surface contact with the charging roller 4 is used, so the pressure applied to the protruding parts of the charging roller 4 that have minute irregularities on its surface can be reduced compared to the case of using a discharge product removal member that comes into line or point contact with the charging roller 4. Therefore, the frictional resistance that occurs when the member comes into sliding contact with the charging roller 4 can also be reduced.

[0029] <Variation 1> As shown in FIG. 5(A), the sheet-like member 30 in the first modification is coated with a polar adsorbent K on a portion (area M) of the surface on the side of the portion that comes into contact with the charging roller 4. Specifically, the sheet-like member 30 shown in FIG. 5(A) is coated with a polar adsorbent K (a coating layer 30b is formed) in a range M of 20 mm from the tip on the surface of the base urethane layer 30a (the surface that comes into contact with the charging roller 4). In addition, a layer 30b containing polar adsorbent K (for example, a layer in which polar adsorbent K is dispersed in an extremely thin film having a thickness of 1 mm or less) can be formed on a part (range M) of the side of the base urethane layer 30a that contacts the charging roller 4. 5(B), the entire surface of the sheet-like member 30 that comes into contact with the charging roller 4 is coated with the polar adsorbent K. Alternatively, a layer 30 containing the polar adsorbent K is formed on the entire surface of the sheet-like member 30 that comes into contact with the charging roller 4. Even in the case of such a configuration, the discharge products adhering to the surface of the charging roller 4 can be removed sufficiently and stably.

[0030] <Variation 2> As shown in FIG. 6, the charging device 3 in the second modification is provided with a moving mechanism 70 that moves the sheet-like member 30 so that the contacting portion of the sheet-like member 30 (the portion that contacts the charging roller 4) is displaced. Specifically, the moving mechanism 70 is configured to be able to move the support member 31 together with the sheet-like member 30 downward from the reference position shown in FIG. 6(A) (to the position shown in FIG. 6(B)) under the control of the control unit 80. As the moving mechanism 70, for example, one consisting of a pinion and rack mechanism can be used. The control unit 80 is provided in the image forming apparatus 100, and performs various controls in the apparatus by the CPU executing a program. By providing the moving mechanism 70 in this manner, the portion (contact portion) of the sheet-like member 30 that contacts the charging roller 4 can be displaced, so that even if the contact portion wears down due to sliding contact with the charging roller 4, another contact portion can be brought into contact with the charging roller 4. Therefore, the life of the sheet-like member 30 can be extended. For this reason, when the sheet-like member 30 is new, the sheet-like member 30 is set at the reference position shown in Figure 6(A), and when the driving time of the charging roller 4 (or the number of printed sheets) reaches a predetermined value by the timer 90, the moving mechanism 70 is driven to move the sheet-like member 30 to the position shown in Figure 6(B). 6, the sheet-like member 30 is displaced from the reference position in one step, but the sheet-like member 30 may be displaced from the reference position in multiple steps. In that case, the sheet-like member 30 is displaced by one step each time the driving time of the charging roller 4 (or the number of printed sheets) reaches a predetermined value. 6, for simplicity, the sheet-like member 30 is illustrated as being moved vertically downward by the moving mechanism 70, but the moving direction of the sheet-like member 30 by the moving mechanism 70 is not limited to this. In particular, it is preferable to determine the moving direction so that even if the sheet-like member 30 is moved by the moving mechanism 70, the change in the contact pressure with the charging roller 4 falls within a predetermined range. In the example of FIG. 6, the movement mechanism 70 is automatically controlled and driven, but the movement mechanism 70 may also be configured to be driven manually.

[0031] <Modification 3> As shown in FIG. 7, in the charging device 3 of the modified example 3, the sheet-like member 30 is configured so as to be able to come into contact with the charging roller 4 in a state in which it is elastically deformed into a bow shape even when the sheet-like member 30 is turned over, and at least the portion that comes into contact with the charging roller 4 is formed of a material containing a polar adsorbent K. That is, whether the sheet-like member 30 is used so that the front surface 30m contacts the charging roller 4 as shown in FIG. 7(A) or the sheet-like member 30 is used so that the back surface 30n contacts the charging roller 4 as shown in FIG. 7(B), the portion M formed of the material containing the polar adsorbent K contacts the charging roller 4 in an arched shape with a desired contact pressure, making it possible to remove discharge products adhering to the surface of the charging roller 4. With this configuration, the portion of the sheet-like member 30 that contacts the charging roller 4 (the contact portion containing the polar adsorbent K) can be changed, so that even if the contact portion wears out due to sliding contact with the charging roller 4, the sheet-like member 30 can be turned over and a different contact portion can be newly brought into contact with the charging roller 4. Therefore, the life of the sheet-like member 30 can be extended. For this reason, when the sheet-like member 30 is new, as shown in FIG. 7(A), the front surface 30m of the sheet-like member 30 is set so as to contact the charging roller 4, and when the driving time of the charging roller 4 (or the number of printed sheets) reaches a predetermined value, as shown in FIG. 6(B), the sheet-like member 30 is turned over together with the support member 31, and the sheet-like member 30 is set so as to contact the back surface 30n of the sheet-like member 30. In the example of Figure 7, polar adsorbent K is contained in a predetermined range M on each of the front surface 30m and the back surface 30n of one sheet-like member 30, but the form of the sheet-like member 30 is not limited to this. For example, one sheet-like member 30 can be formed by bonding the back surfaces of two sheet-like members each having polar adsorbent K contained in a predetermined range M on their front surfaces together. In the example of FIG. 7, the sheet-like member 30 is manually turned over, but a turning mechanism may be provided so that the sheet-like member 30 is automatically turned over by the turning mechanism.

[0032] As described above, the charging device 3 in this embodiment is provided with the charging roller 4 that rotates in a predetermined rotation direction. Also, at least the portion that contacts the charging roller 4 is made of a material containing a polar adsorbent K, and the sheet-like member 30 that contacts the charging roller 4 in a state of being elastically deformed into a bow shape is provided. This makes it possible to sufficiently and stably remove the discharge products adhering to the surface of the charging roller 4.

[0033] In this embodiment, the photosensitive drum 1, charging device 3, developing device 5, and cleaning device 2 are integrated into a process cartridge 6, thereby making the imaging section compact and improving the ease of maintenance. On the other hand, these components may be configured not to be components of the process cartridge, but to be installed individually and replaceably in the image forming apparatus main body 1. In such a case, the same effect as that of the present embodiment can be obtained. In this application, a "process cartridge" is defined as a unit in which at least one of a charging device for charging an image carrier, a developing device for developing a latent image formed on the image carrier, and a cleaning device for cleaning the image carrier is integrated with an image carrier, and is detachably installed in the main body of an image forming apparatus.

[0034] In this embodiment, the present invention is applied to a monochrome image forming apparatus 100 in which a toner image is transferred to a sheet P by one image creating unit (process cartridge 6). However, the present invention can also be applied to a color image forming apparatus in which a toner image is primarily transferred to an intermediate transfer body such as an intermediate transfer belt by a plurality of image creating units, and then the toner image is secondarily transferred from the intermediate transfer body to a sheet. Even in such a case, the same effect as that of this embodiment can be obtained.

[0035] It is clear that the present invention is not limited to the present embodiment, and that the present embodiment may be modified as appropriate within the scope of the technical concept of the present invention in addition to the modifications suggested in the present embodiment. Furthermore, the number, position, shape, etc. of the components are not limited to the present embodiment, and may be any number, position, shape, etc. suitable for implementing the present invention. [Explanation of symbols]

[0036] 1 Photoconductor drum (image carrier), 3 Charging device, 4. Charging roller (charging member, rotating body), 6 Process cartridge, 30 sheet-shaped member (discharge product removal member), 31 Support member, 70 movement mechanism; 100 Image forming apparatus (image forming apparatus main body), K polar adsorbent, M range (adsorbent content range).

[0037] The present invention can also be embodied in the following combinations of Supplementary Notes 1 to 10. (Appendix 1) A charging roller that rotates in a predetermined direction; a sheet-like member, at least a portion of which contacts the charging roller, being made of a material containing a polar adsorbent, and which contacts the charging roller in a state of being elastically deformed into a bow shape; A charging device comprising: (Appendix 2) 2. The charging device according to claim 1, wherein the sheet-like member has a tip end that contacts the belly along the direction of rotation. (Appendix 3) 3. The charging device according to claim 1, wherein the sheet-like member is cantilevered on a support member so that the contacting portion is a free end. (Appendix 4) The charging device according to any one of claims 1 to 3, wherein the sheet-like member is coated with the polar adsorbent on all or part of the surface on the side of the contact portion. (Appendix 5) The charging device according to any one of claims 1 to 3, wherein the sheet-like member has a layer containing the polar adsorbent formed on all or part of the side of the contacting portion. (Appendix 6) 6. The charging device according to claim 1, further comprising a moving mechanism that moves the sheet-like member so that the contacting portion of the sheet-like member is displaced. (Appendix 7) The charging device according to any one of Appendix 1 to Appendix 6, characterized in that the sheet-like member is configured to be able to contact the charging roller in a state where it is elastically deformed into a bow shape even when the sheet-like member is turned over, and at least the portion that contacts the charging roller is formed of a material containing a polar adsorbent. (Appendix 8) A process cartridge that is detachably installed in a main body of an image forming apparatus, 8. A process cartridge comprising: the charging device according to claim 1; and an image bearing member that is charged by the charging roller. (Appendix 9) 8. An image forming apparatus comprising the charging device according to claim 1. (Appendix 10) A sheet-like member that contacts a rotating body, A sheet-like member, characterized in that at least the portion that abuts against the rotating body is formed from a material containing a polar adsorbent and is configured to be able to abut against the rotating body in a bow-shaped elastically deformed state. [Prior art documents] [Patent documents]

[0038] [Patent Document 1] JP 2002-278227 A

Claims

1. A charging roller that rotates in a predetermined direction; a sheet-like member, at least a portion of which contacts the charging roller is made of a material containing a polar adsorbent, and which contacts the charging roller in a state of being elastically deformed into a bow shape; A charging device comprising:

2. 2. The charging device according to claim 1, wherein the sheet member has a leading end that contacts the belly so as to be aligned with the direction of rotation.

3. 3. The charging device according to claim 1, wherein the sheet-like member is cantilevered on a supporting member so that the contacting portion is a free end.

4. 3. The charging device according to claim 1, wherein the sheet member has a surface on the side of the contact portion coated with the polar adsorbent, the surface being entirely or partially coated with the polar adsorbent.

5. 3. The charging device according to claim 1, wherein the sheet-like member has a layer containing the polar adsorbent formed on the whole or part of the contacting portion side.

6. 3. The charging device according to claim 1, further comprising a moving mechanism that moves the sheet member so that the contacting portion of the sheet member is displaced.

7. 3. The charging device according to claim 1, wherein the sheet-like member is configured to be capable of contacting the charging roller in a state in which it is elastically deformed into a bow shape even when the sheet-like member is turned over, and at least the portion that contacts the charging roller is formed of a material containing a polar adsorbent.

8. A process cartridge that is detachably installed in a main body of an image forming apparatus, 3. A process cartridge comprising: the charging device according to claim 1; and an image bearing member that is charged by the charging roller.

9. 3. An image forming apparatus comprising the charging device according to claim 1.

10. A sheet-like member that contacts a rotating body, A sheet-like member, characterized in that at least the portion that abuts against the rotating body is formed from a material containing a polar adsorbent and is configured to be able to abut against the rotating body in a bow-shaped elastically deformed state.

Images