Cleaning device and image forming apparatus

Abstract

To provide a cleaning device capable of preventing turning-up and inversion of a cleaning blade with a simple configuration.SOLUTION: A cleaning device 38 comprises a cleaning blade 72 and seal members 80 provided at both side ends of the cleaning blade. The seal member includes a first seal portion extending along a side end surface of the cleaning blade, and a second seal portion 84 extending along a tip surface of the cleaning blade. The second seal portion extends to a position including a first region that is within a charging region but outside a developing region. In the first region, an end portion on the cleaning blade side of the second seal portion is disposed at a position spaced away from the surface of an image carrier.SELECTED DRAWING: Figure 7

Description

Technical Field

[0001] This disclosure relates to a cleaning device and an image forming apparatus, and more particularly, for example, to a cleaning device that removes toner remaining on the surface of an image carrier and an image forming apparatus including the same.

Background Art

[0002] An example of a conventional cleaning device is disclosed in Patent Document 1. The cleaning device of Patent Document 1 includes a housing having a cleaning blade disposed parallel to a photoreceptor drum so that a tip edge portion (edge portion) faces the circumferential surface of the photoreceptor drum (image carrier). Sealing members that are in surface contact with the circumferential surfaces of both side portions of the photoreceptor drum are provided outside both side end portions of the cleaning blade in this housing. The sealing members prevent toner leakage from both side end portions of the cleaning blade.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] After image formation, the toner remaining on the surface of the image carrier is removed and recovered by the cleaning blade. However, a part of the recovered toner (waste toner) serves as a lubricant for the edge portion of the cleaning blade. That is, the presence of waste toner at the contact portion between the cleaning blade and the image carrier reduces the frictional resistance between the cleaning blade and the image carrier, preventing the cleaning blade from reversing.

[0005] However, in both end portions (both end portions in the longitudinal direction) of the cleaning blade, particularly in a portion that is within the charging region and outside the developing region, the toner supply amount is small. For this reason, local friction force increase easily occurs in this portion, the contact posture of the cleaning blade with respect to the image carrier becomes unstable, excessive deformation (entrainment) of the edge portion occurs, and eventually, it shifts to curling or inversion of the cleaning blade.

[0006] Therefore, the main object of this disclosure is to provide a novel cleaning device and an image forming apparatus.

[0007] Another object of this disclosure is to provide a cleaning device and an image forming apparatus that can prevent curling and inversion of the cleaning blade with a simple configuration.

Means for Solving the Problems

[0008] A first disclosure is a cleaning device that removes toner remaining on the surface of an image carrier, including a cleaning blade that abuts an edge portion on the tip side against the image carrier to scrape off the toner remaining on the surface of the image carrier, and a seal member provided to abut the surface of the image carrier at each position corresponding to both end portions of the cleaning blade. The seal member has a first seal portion extending along the side end surface of the cleaning blade and a second seal portion extending from one end portion of the first seal portion and extending along the tip end surface of the cleaning blade. The second seal portion extends to a position including a first region that is within the charging region and outside the developing region, and the end portion on the cleaning blade side of the second seal portion in the first region is disposed at a position away from the surface of the image carrier (i.e., the edge portion of the cleaning blade).

[0009] According to the first disclosure, with a simple configuration of stretching the second seal portion of the seal member and disposing the end portion on the cleaning blade side of the second seal portion at a position away from the surface of the image carrier, curling and inversion of the cleaning blade can be appropriately prevented. Further, interference between the second seal portion and the edge portion of the cleaning blade can be avoided, so that problems such as poor cleaning caused thereby can be appropriately prevented.

[0010] The second disclosure is dependent on the first disclosure, and the separation distance between the end portion on the cleaning blade side of the second seal portion in the first region and the surface of the image carrier gradually increases as it goes toward the cleaning blade side.

[0011] The third disclosure is dependent on the second disclosure, and the mounting surface to which the end portion on the cleaning blade side of the second seal portion in the first region is attached is an inclined surface that separates from the surface of the image carrier as it goes toward the cleaning blade side.

[0012] The fourth disclosure is dependent on the first or second disclosure, and the end face on the cleaning blade side of the second seal portion in the first region is in contact with the tip face of the cleaning blade.

[0013] The fifth disclosure is dependent on the first or second disclosure, and the separation distance between the edge on the cleaning blade side and the surface of the image carrier of the second seal portion in the first region is within a range of 0.2 mm or more and less than 0.2 mm larger than the thickness of the cleaning blade.

[0014] The sixth disclosure is dependent on the first or second disclosure, and the second seal portion has a slit extending in a direction orthogonal to the end face from the end face on the cleaning blade side.

[0015] The seventh disclosure is dependent on the sixth disclosure, and the slit is formed at a position within a second region between the side end of the cleaning blade and the side end of the charging region.

[0016] The eighth disclosure is an image forming apparatus including an image carrier, a charging device that charges the surface of the image carrier, and a cleaning device according to the first disclosure that removes toner remaining on the surface of the image carrier.

[0017] The ninth disclosure is dependent on the eighth disclosure, and the charging method of the image carrier by the charging device is a contact charging method.

Advantages of the Invention

[0018] According to this disclosure, curling and inversion of the cleaning blade can be appropriately prevented with a simple configuration.

[0019] The above object, other objects, features, and advantages of this disclosure will become clearer from the detailed description of the embodiments below with reference to the drawings.

Brief Description of the Drawings

[0020]

Figure 1

Figure 2

Figure 3

Figure 4

Figure 5

Figure 6

Figure 7

Figure 8

Figure 9

[0021] [First Embodiment] Referring to FIG. 1, a cleaning device 38 which is a first embodiment of this disclosure is used in an image forming apparatus 10 to remove toner remaining on the surface of a photosensitive drum 36 which is an example of an image carrier after image formation (after transfer). As will be described in detail later, the cleaning device 38 includes a cleaning blade 72 and the like, and is integrated with the photosensitive drum 36, a charging device 40 and the like to constitute a process unit 60.

[0022] First, the basic configuration of the image forming apparatus 10 will be schematically described. In this first embodiment, the front (front face) of the image forming apparatus 10 and its constituent members is defined as the face facing the standing position of the user who operates the image forming apparatus 10, that is, the face on the side where an operation unit (not shown) is provided, and the front-rear direction (depth direction) is defined. Note that the operation unit is provided on the front side of the paper surface of FIG. 1. Also, the left-right direction (lateral direction) of the image forming apparatus 10 and its constituent members is defined based on the state of viewing the image forming apparatus 10 from the front.

[0023] As shown in FIG. 1, the image forming apparatus 10 is a multifunction peripheral (MFP) having functions such as a copying function, a printer function, a scanner function, and a facsimile function, and forms a multicolor or single-color image on a sheet of paper (recording medium) by an electrophotographic method. The image forming apparatus 10 includes an apparatus main body 12 including an image forming unit 30 and the like, and an image reading device 14 disposed above the apparatus main body 12.

[0024] The image reading device 14 includes a document placement table 16 formed of a transparent material. On the document placement table 16, a document pressing cover 18 is attached via a hinge or the like so as to be openable and closable. An ADF (Automatic Document Feeder) 24 is provided on the document pressing cover 18 to automatically feed the documents placed on the document placement tray 20 one by one to the image reading position 22. Although not shown, an operation unit (operation panel) for receiving input operations such as printing instructions by the user is provided on the front side of the document placement table 16. The operation unit is appropriately provided with a touch panel display, operation buttons, and the like.

[0025] The image reading device 14 also incorporates an image reading unit 26 including a light source, a plurality of mirrors, an imaging lens, a line sensor, and the like. The image reading unit 26 exposes the document surface with the light source and guides the reflected light reflected from the document surface to the imaging lens by the plurality of mirrors. Then, the imaging lens forms the reflected light on the light receiving elements of the line sensor. In the line sensor, the luminance and chrominance of the reflected light formed on the light receiving elements are detected, and image data based on the image on the document surface is generated. As the line sensor, a CCD (Charge Coupled Device), a CIS (Contact Image Sensor), or the like is used.

[0026] The apparatus main body 12 incorporates a control unit (not shown) including a CPU and a memory, an image forming unit 30, and the like. The control unit transmits control signals to each part of the image forming apparatus 10 according to input operations by the user on the operation unit or the like, and causes the image forming apparatus 10 to execute various operations.

[0027] The image forming unit 30 includes an exposure unit 32, a developing unit 34, a photosensitive drum 36, a cleaning device 38, a charging device 40, an intermediate transfer belt unit 42, a transfer roller 44, a fixing unit 46, and the like. It forms an image on the paper conveyed from a paper feed tray 48 or the like and discharges the paper with the image formed thereon to a paper discharge tray 50. As the image data for forming an image on the paper, the image data read by the image reading unit 26, the image data transmitted from an external computer, or the like is used.

[0028] Note that the image data processed by the image forming apparatus 10 corresponds to a four-color color image of black (K), cyan (C), magenta (M), and yellow (Y). Therefore, each of the developing unit 34, the photosensitive drum 36, the cleaning device 38, and the charging device 40 is provided in four units so as to form four types of latent images corresponding to each color, and four image stations are configured by these.

[0029] The photosensitive drum 36 is an image carrier having a photosensitive layer formed on its surface, and is rotatable about its axis by a drive unit (not shown). The charging device 40 includes a charging roller 40a (see FIG. 2) and the like, and charges the surface of the photosensitive drum 36 to a predetermined potential. The exposure unit 32 is configured as a laser scanning unit (LSU) including a laser diode, a polygon mirror, and the like, and forms an electrostatic latent image corresponding to the image data on the surface of the charged photosensitive drum 36 by exposing the surface of the photosensitive drum 36. The developing unit 34 includes a developing roller 34a and the like, supplies toner to the surface of the photosensitive drum 36, and visualizes the electrostatic latent image formed on the surface of the photosensitive drum 36 with toner (forms a toner image).

[0030] The cleaning device 38 removes and collects the toner remaining on the surface of the photosensitive drum 36 after the transfer of the toner image to the intermediate transfer belt 52. The toner (waste toner) collected by the cleaning device 38 is discharged to a waste toner box (not shown) provided in the front portion inside the apparatus main body 12. As shown in FIG. 2, the photosensitive drum 36, the cleaning device 38, and the charging device 40 are integrated (cartridgeized), and a process unit 60 is configured by these. The specific configurations of the process unit 60 and the cleaning device 38 will be described later.

[0031] Returning to FIG. 1, the intermediate transfer belt unit 42 includes an intermediate transfer belt 52, a driving roller, a driven roller, four intermediate transfer rollers 54, etc. The intermediate transfer belt 52 is provided so as to contact each photoreceptor drum 36. By sequentially superimposing and transferring the toner images of respective colors formed on each photoreceptor drum 36 onto the intermediate transfer belt 52 using the intermediate transfer rollers 54, a multicolor toner image is formed on the intermediate transfer belt 52. Further, a transfer roller 44 is disposed near the driving roller, and the toner image formed on the intermediate transfer belt 52 is transferred onto the paper as the paper passes through the nip area between the intermediate transfer belt 52 and the transfer roller 44.

[0032] The fixing unit 46 includes a heat roller, a pressure roller, etc., and is disposed above the transfer roller 44. The heat roller is set to a predetermined fixing temperature, and as the paper passes through the nip area between the heat roller and the pressure roller, the toner image transferred onto the paper is melted, mixed, and pressed together, and the toner image is thermally fixed to the paper.

[0033] Also, inside the apparatus main body 12, a first paper conveyance path L1 is formed for sending the paper from the paper feed tray 48, etc. to the paper discharge tray 50 via the registration roller 56, the transfer roller 44, and the fixing unit 46. Further, when performing double-sided printing on the paper, a second paper conveyance path L2 is formed for returning the paper after single-sided printing is completed and it has passed through the fixing unit 46 to the first paper conveyance path L1 on the upstream side in the paper conveyance direction of the transfer roller 44. A plurality of conveyance rollers 58 for auxiliary applying a propulsive force to the paper are appropriately provided on the first paper conveyance path L1 and the second paper conveyance path L2.

[0034] Next, the configuration of the process unit 60 will be described. As shown in FIGS. 2 and 3, the process unit 60 includes a photoreceptor drum 36, a cleaning device 38, a charging device 40, etc., and these are integrally held in a predetermined arrangement by a process frame 62.

[0035] The photosensitive drum 36 includes a drum body 36a having a photosensitive layer formed on the surface of a cylindrical substrate with conductivity, and is provided so as to extend in the front-rear direction. At both ends of the drum body 36a, flanges are fixedly attached, and a metal drum shaft 36b is provided so as to penetrate the center of the flange. Both ends of the drum shaft 36b are rotatably supported by bearings provided on the process frame 62. Although not shown, a drive motor is connected to the rear end of the drum shaft 36b via a coupling portion, a gear train, etc. The drum body 36a rotates along with the rotation of the drum shaft 36b. That is, the photosensitive drum 36 is rotatably supported around the drum shaft 36b by the process frame 62 and rotates by the driving force transmitted from the drive motor.

[0036] The charging device 40 includes a charging roller 40a, a cleaning roller 40b, etc., and is provided below the photosensitive drum 36. The charging roller 40a is slightly larger than the developing roller 34a and has an axial length slightly smaller than that of the photosensitive drum 36 (strictly speaking, the drum body 36a), and is arranged parallel to the photosensitive drum 36. The charging roller 40a charges the surface of the photosensitive drum 36 to a predetermined potential while rotating passively along with the rotation of the photosensitive drum 36 in a state where the surface (outer surface) is in contact with the surface of the photosensitive drum 36 with a predetermined pressure. That is, in this embodiment, a contact charging method is adopted as the charging method of the photosensitive drum 36. Further, the cleaning roller 40b is arranged so as to contact the surface of the charging roller 40a at a position opposite to the photosensitive drum 36, and removes foreign matters such as toner attached to the outer peripheral surface of the charging roller 40a.

[0037] The cleaning device 38 includes a storage tank 70, a cleaning blade 72, a conveying screw 74, etc., and is provided on the side of the photosensitive drum 36.

[0038] The storage tank 70 forms part of the process frame 62 and is formed in an elongated cylindrical shape extending in the front-rear direction along the photoreceptor drum 36. An opening is formed in the side portion of the storage tank 70, and a cleaning blade 72 is provided so as to extend in the front-rear direction along the lower edge of this opening.

[0039] The cleaning blade 72 is a long plate-shaped member formed of an elastic material such as urethane rubber. The thickness of the cleaning blade 72 is, for example, 2 mm. The edge portion 72a of the cleaning blade 72 is brought into contact with the surface of the photoreceptor drum 36 on the downstream side (that is, after transfer) in the rotation direction of the photoreceptor drum 36 from the transfer position to the intermediate transfer belt 52, and mechanically scrapes off and removes the toner remaining on the surface of the photoreceptor drum 36 after transfer. The toner (waste toner) scraped off by the cleaning blade 72 is stored in the storage tank 70. A transport screw 74 is rotatably provided in this storage tank 70. The transport screw 74 rotates by the driving force transmitted from the drive motor, and transports the toner scraped off by the cleaning blade 72 and stored in the storage tank 70 to the waste toner box.

[0040] Also, the cleaning blade 72 is provided so as to extend over substantially the entire length of the drum body 36a of the photoreceptor drum 36, and the length in its longitudinal direction (front-rear direction) is set to be slightly smaller than the axial length of the drum body 36a. Also, as described above, the charging roller 40a is slightly larger than the developing roller 34a and has an axial length slightly smaller than the drum body 36a of the photoreceptor drum 36. That is, the charging region R2 on the photoreceptor drum 36 is wider than the developing region R1.

[0041] Furthermore, seal members 80 (side seals) are provided at positions corresponding to both side ends of the cleaning blade 72 so as to be in contact (surface contact) with the surface of the photoreceptor drum 36. The seal members 80 prevent the leakage of toner from both side ends of the cleaning blade 72 to the outside of the storage tank 70.

[0042] In the process unit 60 equipped with such a cleaning device 38, as described above, the toner remaining on the surface of the photoreceptor drum 36 after transfer is removed and recovered by the cleaning blade 72. This recovered toner (waste toner) serves as a lubricant at the edge portion 72a of the cleaning blade 72 (the contact portion between the cleaning blade 72 and the photoreceptor drum 36). Therefore, if the situation where there is little toner continues at the edge portion 72a of the cleaning blade 72, the frictional resistance increases and there is a risk that the cleaning blade 72 will reverse. In particular, at both end portions of the cleaning blade 72 (more specifically, the portion within the charging area of the photoreceptor drum 36 and outside the developing area), the supply amount of toner is small, so the cleaning blade 72 is likely to reverse or curl. Moreover, particularly in the case of a device using the contact charging method, oxidation due to microdischarge easily progresses on the surface of the photoreceptor drum 36, and the symptom that the frictional force with the cleaning blade 72 increases due to surface property changes is added, making the cleaning blade 72 more likely to reverse or curl.

[0043] Therefore, in this first embodiment, the arrangement mode of the seal member 80 is devised so that the seal member 80 also functions as a toner holding member, enabling the toner to be continuously supplied to the edge portions 72a at both end portions of the cleaning blade 72, and appropriately preventing the curling and reversal of the cleaning blade 72 with a simple configuration. This will be specifically described below.

[0044] As shown in FIGS. 3 and 4, the seal member 80 has a first seal portion 82 and a second seal portion 84, and is provided at each position corresponding to both side end portions of the cleaning blade 72. The first seal portion 82 extends in the circumferential direction of the photosensitive drum 36 along the side end surface (end surface in the longitudinal direction) of the cleaning blade 72. The second seal portion 84 extends from one end portion of the first seal portion 82 (the upstream end portion in the rotation direction of the photosensitive drum 36) and extends in the axial direction of the photosensitive drum 36 along the tip surface 72b (edge portion 72a) of the cleaning blade 72. That is, the second seal portion 84 is disposed on the upstream side of the cleaning blade 72 in the rotation direction of the photosensitive drum 36.

[0045] The seal member 80 is formed of a material having sealing properties and flexibility such as a nonwoven fabric, a woven fabric, and a foam material. In this embodiment, the seal member 80 is formed of a mocket material. The thickness of the seal member 80 is, for example, 3 mm. Further, the seal member 80 is fixed to the mounting portion 90 formed on the process frame 62 by using a double-sided tape, an adhesive, or the like. As can be clearly seen from FIGS. 4 and 5, the mounting portion 90 of the seal member 80 includes a mounting surface 90a to which the end portion of the second seal portion 84 on the cleaning blade 72 side is attached. This mounting surface 90a is an inclined surface that moves away from the surface of the photosensitive drum 36 as it goes toward the cleaning blade 72 side (the lower side in FIG. 5). Thereby, as will be described later, the end portion of the second seal portion 84 on the cleaning blade 72 side is disposed at a position away from the surface of the photosensitive drum 36, and the separation distance gradually increases as it goes toward the cleaning blade 72 side.

[0046] Then, as shown in FIGS. 3 and 6, the second seal portion 84 of the seal member 80 extends to a position including a first region R3 that is within the charging region R2 (strictly, the drum main body 36a of the photosensitive drum 36) and outside the developing region R1. This extended second seal portion 84 functions as a toner holding portion as will be described later. At this time, the second seal portion 84 may be formed up to at least a position including the outer end portion (longitudinal end portion of the charging region R2) of the first region R3. More preferably, it may be formed up to a position extending over the entire length of the first region R3 (the entire length in the axial direction of the photosensitive drum 36). In the case of the contact charging method, the state change of the surface of the photosensitive drum 36 due to the discharge action is large, and at the charging end portion, the frictional force difference tends to be large at the adjacent portion between the charged region and the non-charged region, and the blade edge is likely to be twisted, and thus the cleaning blade 72 is likely to be curled or reversed. Further, the second seal portion 84 may be formed up to a position including the longitudinal end portion of the developing region R1. This is because at the longitudinal end portion of the developing region R1, the frictional force difference may become large depending on the presence or absence of toner supply as a lubricant, and the blade edge may be easily twisted. These selections may be appropriately made in view of the behavior in the image forming apparatus 10. In this embodiment, the second seal portion 84 extends to a position slightly entering the longitudinal end portion of the developing region R1.

[0047] Also, as shown in FIGS. 6 and 7, the end of the second seal portion 84 on the cleaning blade 72 side is disposed at a position away from the surface of the photoreceptor drum 36, and a space 88 with a predetermined interval is formed between the end of the second seal portion 84 on the cleaning blade 72 side and the surface of the photoreceptor drum 36. This space 88 is formed from the tip of the second seal portion 84 (the inner end in the axial direction of the photoreceptor drum 36) to a position including the first region R3, and functions as a toner storage space as will be described later. Further, by separating the end of the second seal portion 84 on the cleaning blade 72 side from the surface of the photoreceptor drum 36 (that is, the edge portion 72a of the cleaning blade 72), interference of the second seal portion 84 with the edge portion 72a of the cleaning blade 72 can be avoided. At this time, it is preferable that the space 88 is formed up to a position including the outer end portion of the first region R3 (the longitudinal end portion of the charging region R2). This is because, as described above, curling and inversion of the cleaning blade 72 easily occur in this portion. In this embodiment, the space 88 is formed up to substantially the entire length of the second seal portion 84, that is, up to a position near the side end surface of the cleaning blade 72.

[0048] Also, the separation distance between the end of the second seal portion 84 on the cleaning blade 72 side and the surface of the photoreceptor drum 36 (the size of the space 88 in the radial direction of the photoreceptor drum 36) preferably gradually increases toward the cleaning blade 72 side. In this embodiment, by making the mounting surface 90a on which the end of the second seal portion 84 on the cleaning blade 72 side is mounted an inclined surface, the size of the space 88 gradually increases toward the cleaning blade 72 side. Note that, instead of making the mounting surface 90a an inclined surface, a space 88 can also be formed between the end of the second seal portion 84 on the cleaning blade 72 side and the surface of the photoreceptor drum 36 by making the mounting surface 90a recessed in a stepped shape. However, considering the stability of the fixing state of the seal member 80 to the mounting portion 90, it is preferable that the mounting surface 90a is an inclined surface.

[0049] Furthermore, even when a space 88 is formed between the end portion of the second seal portion 84 on the cleaning blade 72 side and the surface of the photosensitive drum 36, it is preferable that the end face 84b of the second seal portion 84 on the cleaning blade 72 side is in contact with the tip face 72b of the cleaning blade 72 at least in a part in the radial direction of the photosensitive drum 36. This is because if these end faces 72b and 84b are separated from each other, toner may leak from the gap between the end faces 72b and 84b, and it may not be possible to appropriately store the toner in the space 88.

[0050] Also, the separation distance between the edge 84a of the second seal portion 84 on the cleaning blade 72 side and on the photosensitive drum 36 side and the surface of the photosensitive drum 36 is preferably in the range of 0.2 mm or more and less than 0.2 mm larger than the thickness of the cleaning blade 72. For example, when the thickness of the cleaning blade 72 is 2.0 mm, the edge 84a of the second seal portion 84 may be arranged within the range of a separation distance of 0.2 mm to 1.8 mm from the edge portion 72a. This is because if the separation distance between the edge 84a of the second seal portion 84 and the surface of the photosensitive drum 36 is too small, the space 88 becomes small and it becomes difficult to store the toner. Also, although errors (variations) occur due to factors such as component dimensions, mounting accuracy, and aging deterioration, by providing a margin of about 0.2 mm, it is possible to surely prevent the second seal portion 84 from interfering with the edge portion 72a of the cleaning blade 72 or separating from the tip face 72b of the cleaning blade 72.

[0051] Also, as shown in FIG. 8, in the base end portion (the connecting portion with the first seal portion 82) of the second seal portion 84 and the first seal portion 82 outside thereof, it is preferable that they are in contact (surface contact) with the surface of the photosensitive drum 36 over substantially the entire length in the circumferential direction of the photosensitive drum 36. This is to ensure the sealing function by the seal member 80.

[0052] Further, in this embodiment, as shown in FIGS. 4 and 6, the second seal portion 84 has a slit 86 extending in a direction orthogonal to the end face 84b on the cleaning blade 72 side from the end face 84b. This slit 86 is preferably formed at a position within the second region R4 between the side end of the cleaning blade 72 and the side end of the charging region R2. In this embodiment, the slit 86 is formed at the base end portion of the second seal portion 84. By forming the slit 86 in the second seal portion 84, even when a step (the height of the mounting surface changes) occurs in the mounting portion 90 of the seal member 80 to form the space 88, the seal member 80 and the mounting portion 90 can be easily brought into close contact with each other, and good workability and stable sealing performance can be obtained.

[0053] In the cleaning device 38 provided with such a seal member 80, as shown in FIG. 6, a part of the toner (waste toner) scraped from the surface of the photosensitive drum 36 by the cleaning blade 72 enters the space 88 through the edge portion 72a of the cleaning blade 72 from the inside in the axial direction of the photosensitive drum 36 and is stored (held) in this space 88. That is, the space 88 functions as a toner storage space. Then, a small amount of toner stored in the space 88 is gradually re-supplied to the edge portion 72a of the cleaning blade 72 as a lubricant, thereby suppressing a sudden change in the friction coefficient between the photosensitive drum 36 at both ends (the first region R3) of the cleaning blade 72. As a result, curling and inversion of the cleaning blade 72 are appropriately prevented.

[0054] Further, since the end of the second seal portion 84 on the cleaning blade 72 side is separated from the surface of the photoreceptor drum 36, it is possible to avoid the second seal portion 84 from interfering with the edge portion 72a of the cleaning blade 72. If the second seal portion 84 interferes with the edge portion 72a of the cleaning blade 72, toner leakage (cleaning failure) occurs at this interference portion, and fogging due to contamination or charging failure of the charging roller 40a occurs. The fogging toner may cause the cleaning failure to progress, resulting in toner scattering near the seal member 80 and toner sticking to the surface of the photoreceptor drum 36. However, according to this embodiment, this problem can be solved.

[0055] In addition, even in only normal text printing, it is possible to store toner in the space 88. However, in order to ensure the toner storage amount by the second seal portion 84 of the seal member 80 and more reliably prevent the cleaning blade 72 from curling and reversing, solid printing may be executed when a predetermined condition is satisfied. However, in this embodiment, since toner can be stored in the space 88, the lubricating action can be maintained even with a small amount of solid printing. This solid printing may be performed over the entire length of the developing region R1 or only at both end portions of the developing region R1.

[0056] As described above, according to this first embodiment, the second seal portion 84 of the seal member 80 is extended to the first region R3, and the end of the second seal portion 84 on the cleaning blade 72 side in the first region R3 is arranged at a position separated from the surface of the photoreceptor drum 36. With this simple configuration, it is possible to prevent an excessive frictional force from occurring between the photoreceptor drum 36 and the cleaning blade 72, and it is possible to appropriately prevent the cleaning blade 72 from curling and reversing.

[0057] In addition, by arranging the end of the second seal portion 84 on the cleaning blade 72 side at a position separated from the surface of the photoreceptor drum 36, it is possible to avoid the interference of the second seal portion 84 with the edge portion 72a of the cleaning blade 72, so that problems such as cleaning failure caused thereby can be appropriately prevented.

[0058] [Second Embodiment] Next, with reference to FIG. 9, the cleaning device 38 which is the second embodiment of this disclosure will be described. In this second embodiment, the shapes of the seal member 80 and the mounting portion 90 are different from those of the above-described first embodiment. Since other parts are the same, the same reference numerals are given to the parts common to the above-described first embodiment, and overlapping explanations are omitted or simplified.

[0059] In this second embodiment, instead of making the mounting surface 90a an inclined surface, a recessed portion 84c is formed at the end of the second seal portion 84 on the cleaning blade 72 side, so that the end of the second seal portion 84 on the cleaning blade 72 side is disposed at a position away from the surface of the photosensitive drum 36, and a space 88 with a predetermined interval is formed therebetween. In this embodiment, the recessed portion 84c is formed so that the cross section of the space 88 as viewed in the axial direction of the photosensitive drum 36 is substantially rectangular, but it is not particularly limited thereto. For example, the recessed portion 84c can also be formed so that the size of the space 88 gradually increases toward the cleaning blade 72 side.

[0060] Also in this second embodiment, the same operational effects as those of the first embodiment are achieved, and the curling and inversion of the cleaning blade 72 can be appropriately prevented with a simple configuration.

[0061] Note that in the above-described embodiments, a multi-functional machine combining a copier, a facsimile machine, a printer, etc. is exemplified as the image forming apparatus, but the image forming apparatus may be any one of a copier, a facsimile machine, a printer, etc., or a multi-functional machine combining at least two of these. Further, the image forming apparatus may be a monochrome machine. Furthermore, the image forming apparatus is not limited to an intermediate transfer type, and may be a direct transfer type that directly transfers a toner image from the photosensitive drum to the paper.

[0062] Note that all of the specific component shapes, dimensions, arrangement modes, etc. listed above are merely examples, and can be appropriately changed according to the requirements such as the product specifications.

Description of Symbols

[0063] 10 … Image forming apparatus 12 … Apparatus main body 30 … Image forming unit 36 … Photoconductor drum (image carrier) 38 … Cleaning device 40 … Charging device 60 … Process unit 72 … Cleaning blade 72a … Edge portion 72b … Front end surface 80 … Sealing member 82 … First seal portion 84 … Second seal portion 86 … Slit 88 … Space (toner storage space)

Claims

1. A cleaning device for removing toner remaining on the surface of an image carrier, comprising: a cleaning blade that scrapes off toner remaining on the surface of the image carrier by bringing an edge portion on the tip side into contact with the image carrier; and sealing members provided so as to contact the surface of the image carrier at positions corresponding to both end portions of the cleaning blade, wherein the sealing member has a first sealing portion extending along a side end surface of the cleaning blade and a second sealing portion extending from one end portion of the first sealing portion and along a tip end surface of the cleaning blade, the second sealing portion extends to a position including a first region that is within a charging region and outside a developing region, and an end portion of the second sealing portion on the cleaning blade side in the first region is disposed at a position away from the surface of the image carrier. A cleaning device.

2. The cleaning device according to claim 1, wherein a separation distance between an end portion of the second sealing portion on the cleaning blade side in the first region and the surface of the image carrier gradually increases toward the cleaning blade side.

3. The cleaning device according to claim 2, wherein a mounting surface to which an end portion of the second sealing portion on the cleaning blade side in the first region is attached is an inclined surface that moves away from the surface of the image carrier toward the cleaning blade side.

4. The cleaning device according to claim 1 or 2, wherein an end surface of the second sealing portion on the cleaning blade side in the first region is in contact with the tip end surface of the cleaning blade.

5. The cleaning device according to claim 1 or 2, wherein a separation distance between an edge on the cleaning blade side and the surface of the image carrier of an end portion of the second sealing portion on the cleaning blade side in the first region is 0.2 mm or more and 0.2 mm less than the thickness of the cleaning blade.

6. The cleaning device according to claim 1 or 2, wherein the second sealing portion has a slit extending in a direction orthogonal to an end surface on the cleaning blade side.

7. The cleaning device according to claim 6, wherein the slit is formed at a position within a second region between a side end of the cleaning blade and a side end of the charging region.

8. An image carrier A charging device for charging the surface of the image carrier, and An image forming apparatus comprising the cleaning device according to claim 1 for removing toner remaining on the surface of the image carrier.

9. The image forming apparatus according to claim 8, wherein the charging method of the image carrier by the charging device is a contact charging method.

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