Cleaning device and image forming apparatus

Abstract

To provide a cleaning device that can prevent turn-up and reversal of a cleaning blade with a simple configuration.SOLUTION: A cleaning device comprises a cleaning blade 72 that is brought into contact with an image carrier at an edge part P1 on a leading end side to scrape off a toner remaining on the surface of the image carrier. The cleaning blade has rugged friction reduction parts 80 formed on a leading end surface 72b.SELECTED DRAWING: Figure 8

Description

[Technical field]

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

[0002] An example of a conventional cleaning device is disclosed in Patent Document 1. The cleaning blade of the cleaning device of Patent Document 1 includes a rectangular elastic substrate having a width corresponding to the length in a direction perpendicular to the moving direction of the member to be cleaned (image carrier), a reinforcing sheet fixed to at least the end of the main surface of the elastic substrate facing the member to be cleaned, reinforcing the end of the elastic substrate and having flexibility to follow the change in surface shape in the width direction accompanying the movement of the member to be cleaned at the ridge portion (edge ​​portion) of the member to be cleaned with which the cleaning blade comes into contact, and a hard lubricating film formed on the reinforcing sheet at least on the ridge portion that comes into contact with the surface of the member to be cleaned, which is harder than the elastic substrate and has a lower friction coefficient with respect to the member to be cleaned than the reinforcing sheet. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] JP 2012-58359 A Summary of the Invention [Problem to be solved by the invention]

[0004] In the technique of Patent Document 1, a reinforcing sheet is provided on the edge portion of the cleaning blade, and a hard lubricating film is also provided, resulting in high costs.

[0005] Therefore, a primary object of this disclosure is to provide a novel cleaning device and image forming apparatus.

[0006] Another object of the present disclosure is to provide a cleaning device and an image forming apparatus that can prevent the cleaning blade from turning over and reversing with a simple configuration. [Means for solving the problem]

[0007] The first disclosure is a cleaning device that removes toner remaining on the surface of an image carrier, and is equipped with a cleaning blade that abuts the edge portion on the tip side of the cleaning blade against the image carrier to scrape off toner remaining on the surface of the image carrier, and the cleaning blade has an uneven friction reducing portion formed on the tip surface.

[0008] According to the first disclosure, the simple configuration of forming an uneven friction reduction portion on the tip surface of the cleaning blade can prevent excessive frictional force from occurring between the image carrier and the cleaning blade, thereby appropriately preventing the cleaning blade from curling up and reversing.

[0009] The second disclosure is dependent on the first disclosure, and the friction reduction portion is formed on a portion of the tip surface of the cleaning blade that is upstream of an edge portion in the rotation direction of the image carrier.

[0010] The third disclosure is dependent on the second disclosure, and the friction reduction portion is formed on the edge portion side of the tip surface of the cleaning blade at a portion 50 μm or more away from the edge end.

[0011] The fourth disclosure is dependent on the first or second disclosure, and the friction reducing portion is formed on both longitudinal ends of the tip surface of the cleaning blade.

[0012] The fifth disclosure is dependent on the fourth disclosure, and the friction reducing portion is provided to include at least a part of a portion that corresponds to a region that is in the charging region and outside the development region.

[0013] The sixth disclosure is dependent on the fifth disclosure, and the friction reducing portion is provided to include at least an end portion of the charging region.

[0014] The seventh disclosure is dependent on the first or second disclosure, and the friction reducing portion is formed so that the contact area when it comes into contact with the image carrier becomes smaller with increasing distance from the edge end on the edge portion side.

[0015] The eighth disclosure is dependent on the first or second disclosure, and the friction reducing portion is formed so that the depth of the recess increases with increasing distance from the edge end on the edge portion side.

[0016] A ninth disclosure is dependent on the first or second disclosure, and the friction reducing portion includes a protrusion formed by the attachment portion.

[0017] A tenth 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. Effect of the Invention

[0018] According to this disclosure, the cleaning blade can be appropriately prevented from curling up and reversing with a simple configuration in which an uneven friction reducing portion is formed on the tip surface of the cleaning blade.

[0019] The above and other objects, features and advantages of the present disclosure will become more apparent from the following detailed description of the embodiments, which proceeds with reference to the drawings. [Brief description of the drawings]

[0020] [Figure 1] 1 is a schematic cross-sectional view showing an internal structure of an image forming apparatus equipped with a cleaning device according to a first embodiment of the present disclosure. [Diagram 2] FIG. 2 is a cross-sectional view showing a process unit included in the image forming apparatus. [Diagram 3] FIG. 2 is a schematic diagram showing the positional relationship of each member in a process unit. [Figure 4] FIG. 4 is a schematic diagram showing a state of a cleaning blade when no load is applied; [Diagram 5]FIG. 2 is a schematic diagram showing the state of a cleaning blade during normal use. [Figure 6] 5A and 5B are schematic diagrams showing the state of the cleaning blade when the retraction is increased. [Figure 7] FIG. 2 is a schematic diagram showing a tip surface of a cleaning blade. [Figure 8] 3 is an enlarged schematic view showing a peripheral portion of a friction reducing portion on the tip surface of the cleaning blade; FIG. [Figure 9] 9 is a schematic diagram showing a cross section of the cleaning blade taken along line IX-IX in FIG. 8. [Figure 10] 13 is a schematic enlarged view showing a peripheral portion of a friction reducing portion on a tip surface of a cleaning blade in a second embodiment. FIG. [Figure 11] 11 is a schematic diagram showing a cross section of the cleaning blade taken along line XI-XI in FIG. 10. [Figure 12] 13 is a schematic enlarged view showing a peripheral portion of a friction reducing portion on the tip surface of a cleaning blade in a third embodiment. FIG. [Figure 13] 13 is a schematic diagram showing a cross section of the cleaning blade taken along line XIII-XIII in FIG. 12. [Figure 14] 13 is an enlarged schematic view showing a peripheral portion of a friction reducing portion on the tip surface of a cleaning blade in a fourth embodiment. FIG. [Figure 15] 15 is a schematic diagram showing a cross section of the cleaning blade taken along line XV-XV in FIG. 14. [Figure 16] FIG. 13 is an enlarged schematic view showing a peripheral portion of a friction reducing portion on a tip surface of a cleaning blade in a fifth embodiment. [Figure 17] 17 is a schematic diagram showing a cross section of the cleaning blade taken along line XVII-XVII in FIG. 16. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

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

[0022] First, a basic configuration of the image forming apparatus 10 will be briefly described. In this first embodiment, the front and rear directions (depth directions) of the image forming apparatus 10 and its components are defined with the surface facing the position of the user who operates the image forming apparatus 10, that is, the surface on which the operation unit is provided, being the front (front). The operation unit is provided on the near side of the paper surface of FIG. 1. The left and right directions (horizontal directions) of the image forming apparatus 10 and its components are defined with the image forming apparatus 10 viewed from the front as the reference.

[0023] 1, the image forming apparatus 10 is a multifunction peripheral (MFP) having a copying function, a printer function, a scanner function, a facsimile function, etc., and forms a multicolor or monochrome image on a sheet (recording medium) by an electrophotographic method. The image forming apparatus 10 includes an apparatus main body 12 equipped with an image forming unit 30, etc., and an image reading device 14 disposed above the apparatus main body 12.

[0024] The image reading device 14 includes an original placement platform 16 formed of a transparent material. An original pressing cover 18 is attached above the original placement platform 16 via a hinge or the like so as to be freely opened and closed. This original pressing cover 18 is provided with an ADF (automatic document feeder) 24 that automatically feeds originals placed on an original placement tray 20 one by one to an image reading position 22. Although not shown, an operation unit (operation panel) that accepts input operations such as printing instructions by a user is provided on the front side of the original placement platform 16. This operation unit is appropriately provided with a touch panel display, operation buttons, etc.

[0025] The image reading device 14 also includes an image reading unit 26 that includes a light source, multiple mirrors, an imaging lens, a line sensor, and the like. The image reading unit 26 exposes the surface of the document to the light source, and guides the light reflected from the document surface to the imaging lens via multiple mirrors. The imaging lens then forms an image of the reflected light on the light receiving element of the line sensor. The line sensor detects the luminance and chromaticity of the reflected light that forms an image on the light receiving element, and generates image data based on the image of the document surface. A CCD (Charge Coupled Device), a CIS (Contact Image Sensor), or the like is used as the line sensor.

[0026] The device main body 12 includes a control unit (not shown) including a CPU, memory, etc., and an image forming unit 30. The control unit transmits control signals to each part of the image forming device 10 in response to an input operation to an operation unit, etc., and causes the image forming device 10 to perform various operations.

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

[0028] The image data handled by the image forming apparatus 10 corresponds to color images of four colors: black (K), cyan (C), magenta (M), and yellow (Y). For this reason, four of each of the developing units 34, photoconductor drums 36, cleaning devices 38, and charging devices 40 are provided so as to form four types of latent images corresponding to each color, and these constitute four image stations.

[0029] The photoconductor drum 36 is an image carrier having a photosensitive layer formed on its surface, and is rotatable around 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 photoconductor drum 36 to a predetermined potential. The exposure unit 32 is configured as a laser scanning unit (LSU) including a laser diode and a polygon mirror and the like, and exposes the charged surface of the photoconductor drum 36 to light, thereby forming an electrostatic latent image on the surface of the photoconductor drum 36 according to image data. The development unit 34 includes a development roller 34a (see FIG. 3) and the like, and supplies toner to the surface of the photoconductor drum 36, and visualizes the electrostatic latent image formed on the surface of the photoconductor drum 36 with the toner (forming a toner image).

[0030] The cleaning device 38 removes and collects the toner remaining on the surface of the photosensitive drum 36 after the toner image is transferred to the intermediate transfer belt 52. The toner (waste toner) collected by the cleaning device 38 is discharged into a waste toner box (not shown) provided in the front part of 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 (formed into a cartridge), and together they constitute a process unit 60. 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 drive roller, a driven roller, and four intermediate transfer rollers 54. The intermediate transfer belt 52 is provided so as to come into contact with each photosensitive drum 36, and the intermediate transfer rollers 54 are used to transfer the toner images of each color formed on each photosensitive drum 36 to the intermediate transfer belt 52 in order, superimposed on top of each other, thereby forming a multi-color toner image on the intermediate transfer belt 52. In addition, a transfer roller 44 is disposed near the drive roller, and the toner image formed on the intermediate transfer belt 52 is transferred to the paper by the paper passing through a nip area between the intermediate transfer belt 52 and the transfer roller 44.

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

[0033] Also, inside the device body 12, a first paper transport path L1 is formed for sending paper from the paper feed tray 48 or the like to the paper output tray 50 via the registration rollers 56, the transfer roller 44 and the fixing unit 46. Also, when performing double-sided printing on the paper, a second paper transport path L2 is formed for returning the paper after single-sided printing is completed and the paper has passed through the fixing unit 46 to the first paper transport path L1 upstream in the paper transport direction of the transfer roller 44. A plurality of transport rollers 58 for providing auxiliary propulsion force to the paper are appropriately provided on the first paper transport path L1 and the second paper transport path L2.

[0034] Next, a description will be given of the configuration of the process unit 60. As shown in Fig. 2, the process unit 60 includes the photoconductor drum 36, the cleaning device 38, the charging device 40, etc., which 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 base body having electrical conductivity, and is provided so as to extend in the front-rear direction. Flanges are fixedly attached to both ends of the drum body 36a so as to be fitted, 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 in the process frame 62. Although not shown, a driving motor is connected to the rear end of the drum shaft 36b via a coupling portion, a gear train, and the like. The drum body 36a rotates with the rotation of the drum shaft 36b. In other words, 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 driving motor.

[0036] The charging device 40 includes a charging roller 40a and a cleaning roller 40b, and is provided below the photosensitive drum 36. The charging roller 40a has an axial length that is slightly larger than the developing roller 34a in the longitudinal direction and slightly smaller than the photosensitive drum 36 (strictly speaking, the drum body 36a) (see FIG. 3), and is disposed parallel to the photosensitive drum 36. The charging roller 40a charges the surface of the photosensitive drum 36 to a predetermined potential while rotating in accordance with the rotation of the photosensitive drum 36 with its surface (outer surface) in contact with the surface of the photosensitive drum 36 at a predetermined pressure. That is, in this embodiment, a contact charging method is adopted as the charging method for the photosensitive drum 36. However, the charging method for the photosensitive drum 36 is not particularly limited, and for example, a charging method using discharge in a small gap may be adopted. The cleaning roller 40b is disposed on the opposite side to the photoconductor drum 36 so as to come into contact with the surface of the charging roller 40a, and removes foreign matter such as toner adhering to the outer circumferential surface of the charging roller 40a.

[0037] The cleaning device 38 includes a container 70, a cleaning blade 72, a conveying screw 74, etc., and is provided to the right of the photoconductor drum 36.

[0038] The container 70 constitutes part of the process frame 62, and is formed in a long, thin cylinder shape extending in the front-rear direction along the photosensitive drum 36. An opening is formed in the left side of the container 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 plate-like member made of an elastic material such as urethane rubber. An edge portion of the cleaning blade 72 contacts the surface of the photoconductor drum 36 downstream in the rotation direction of the photoconductor drum 36 from the transfer position to the intermediate transfer belt 52 (i.e., after transfer), and mechanically scrapes off and removes the toner remaining on the surface of the photoconductor drum 36 after transfer. The toner (waste toner) scraped off by the cleaning blade 72 is stored in a storage tank 70. A conveying screw 74 is rotatably provided in the storage tank 70. The conveying screw 74 is rotated by a driving force transmitted from a drive motor, thereby conveying the toner scraped off by the cleaning blade 72 and stored in the storage tank 70 to a waste toner box.

[0040] 3, the cleaning blade 72 is provided so as to extend over substantially the entire length of the drum body 36a of the photosensitive drum 36, and its longitudinal (front-rear) size is set to be substantially the same as the axial length of the drum body 36a. As described above, the charging roller 40a has an axial length that is slightly larger than the developing roller 34a and slightly smaller than the drum body 36a of the photosensitive drum 36. That is, the charging region R2 of the photosensitive drum 36 is wider than the developing region R1.

[0041] In the process unit 60 equipped with such a cleaning device 38, as described above, the toner remaining on the surface of the photosensitive drum 36 after transfer is removed and collected by the cleaning blade 72. This collected toner (waste toner) serves as a lubricant for the edge portion of the cleaning blade 72 (the contact portion between the cleaning blade 72 and the photosensitive drum 36). For this reason, if the amount of toner on the edge portion of the cleaning blade 72 continues to be small, frictional resistance increases and the cleaning blade 72 may turn over. In particular, at both ends in the longitudinal direction of the cleaning blade 72 (more specifically, the portion within the charging area of ​​the photosensitive drum 36 but outside the developing area), the supply of toner is reduced, so that the cleaning blade 72 is likely to turn over or roll up. In addition, in the case of a charging method that uses discharge by contact or a small gap, oxidation due to small discharges is likely to progress on the surface of the photosensitive drum 36, and the frictional force with the cleaning blade 72 increases due to changes in surface properties, making the cleaning blade 72 more likely to turn over or roll up.

[0042] Here, as shown in FIG. 4, the cleaning blade 72 has an edge 72a on the tip side formed in a sharp linear shape, and is provided so that the edge 72a abuts against the surface of the photosensitive drum 36 with a predetermined pressure when the photosensitive drum 36 is not rotating (i.e., under no load). Also, as shown in FIG. 5, when the photosensitive drum 36 rotates in a normal state (i.e., during normal use), the edge portion of the cleaning blade 72 is pulled in by the photosensitive drum 36 and undergoes slight deformation. The cleaning blade 72 strongly contacts the photosensitive drum 36 at an edge portion P1, which is a portion from the edge 72a of the tip surface 72b to a position slightly upstream in the rotation direction of the photosensitive drum 36. Specifically, the edge portion P1, which is a portion from the edge 72a of the tip surface 72b to a position about 0 to several tens of μm, becomes the abutting portion against the photosensitive drum 36. The edge portion P1 of the cleaning blade 72 exerts a strong blocking force due to the pressing force (load) against the photosensitive drum 36 and the recovery force (elastic restoring force) of the deformed portion, and scrapes off and removes the toner remaining on the surface of the photosensitive drum 36.

[0043] However, as shown in FIG. 6, when the contact state between the photosensitive drum 36 and the cleaning blade 72 becomes unstable due to a decrease in the toner serving as a lubricant, the cleaning blade 72 is pulled in by the photosensitive drum 36 to a large extent, and the contact portion expands to a wider area (enlarged edge portion P2) than the edge portion P1, which is the contact portion during normal use. According to the verification experiment conducted by the inventors, when the pulling is increased, the enlarged edge portion P2, which is a portion from the edge end 72a of the tip surface 72b to a distance of about several tens to several hundreds of μm, comes into strong contact with the photosensitive drum 36, and a larger frictional force is applied. It was also found that when the enlarged edge portion P2 continues to rotate in a state in which it is in contact with the photosensitive drum 36, the cleaning blade 72 is turned over (and thus reversed) at that portion. This turning over phenomenon (reversal phenomenon) is likely to occur in the regions at both ends in the longitudinal direction of the cleaning blade 72, where the supply of toner is small.

[0044] Therefore, in this first embodiment, uneven friction reducing portions 80 are formed on the tip surface 72b (so-called cut surface) of the cleaning blade 72 to prevent the occurrence of excessive frictional force, thereby appropriately preventing the cleaning blade 72 from turning over and reversing. This will be specifically described below.

[0045] As shown in FIG. 7, the friction reduction portion 80 is formed at both ends of the tip surface 72b in the longitudinal direction of the cleaning blade 72. In this case, it is preferable that the friction reduction portion 80 is formed so as to include at least a part of the portion corresponding to the region R3 that is within the charged region R2 of the photosensitive drum 36 (strictly speaking, the drum body 36a) and outside the development region R1. More preferably, the friction reduction portion 80 is formed so as to include the end of the charged region R2. In particular, in the case of a charging method using contact charging or micro-gap discharge, as described above, the state change of the surface of the photosensitive drum 36 due to the discharge action is large, and the friction force difference is likely to be large at the adjacent portion between the charged region and the non-charged region at the charged end, and twisting of the blade edge, and even rolling up or reversal, are likely to occur. In addition, the friction reduction portion 80 may be formed so as to include the end of the development region R1. This is because, at the end of the development region R1, the friction force difference is large depending on the presence or absence of toner supply as a lubricant, and twisting of the blade edge may easily occur as described above. These options may be selected appropriately in consideration of the behavior of the cleaning blade 72 in the image forming apparatus 10. The friction reducing portions 80 may be formed continuously or intermittently over the entire length of the cleaning blade 72 in the longitudinal direction.

[0046] 8 and 9, the friction reduction portion 80 is preferably formed upstream of the edge portion P1 in the rotation direction of the photosensitive drum 36. In other words, the friction reduction portion 80 is preferably not formed in the edge portion P1, but is formed at a position that does not contact the photosensitive drum 36 during normal use. In this embodiment, the friction reduction portion 80 is formed at a position that is a predetermined distance (for example, 50 μm or more) away from the edge end 72a on the edge portion P1 side of the tip surface 72b of the cleaning blade 72, and at a predetermined portion P3 in the enlarged edge portion P2 that becomes the contact portion when the retraction is increased. Specifically, the predetermined portion P3 in this embodiment is a portion from a position 50 μm away from the edge end 72a of the tip surface 72b to 300 μm from the edge end 72a.

[0047] In this embodiment, a plurality of hemispherical recesses 80a are formed on the tip surface 72b by laser processing or cutting processing, thereby forming an uneven friction reducing portion 80 including recesses 80a and protrusions 80b. The opening diameter of the recesses 80a is preferably set to, for example, 20 μm or more and 100 μm or less. However, the shape, size, arrangement, and formation range of the recesses 80a (and thus the friction reducing portion 80) can be appropriately changed.

[0048] In the image forming apparatus 10 equipped with such a cleaning blade 72, the edge portion P1 that contacts the photosensitive drum 36 during normal use does not have the friction reducing portion 80 formed thereon, so that the toner blocking force of the edge portion P1 is properly maintained without being reduced. Therefore, the cleaning function of the cleaning blade 72 on the photosensitive drum 36 during normal use is properly exhibited. On the other hand, when the contact state between the photosensitive drum 36 and the cleaning blade 72 becomes unstable due to a decrease in the toner that serves as a lubricant, the contact portion expands to a portion (enlarged edge portion P2) that is wider than the edge portion P1. However, since the friction reducing portion 80 is formed in this portion, the friction force between the photosensitive drum 36 and the cleaning blade 72 is prevented from becoming too large. When excessive friction force is not generated, the cleaning blade 72 returns to the shape of the normal state where the edge portion P1 contacts due to its own elastic restoring force. In other words, excessive friction force is prevented from being generated between the photosensitive drum 36 and the cleaning blade 72, and the cleaning blade 72 is prevented from turning over and reversing.

[0049] As described above, according to this first embodiment, with the simple configuration of forming an uneven friction reduction portion 80 on the tip surface 72b of the cleaning blade 72, it is possible to prevent excessive frictional force from occurring between the photosensitive drum 36 and the cleaning blade 72, and therefore it is possible to appropriately prevent the cleaning blade 72 from curling up and reversing.

[0050] [Second Example] Next, a cleaning blade 72 provided in a cleaning device 38 according to a second embodiment of this disclosure will be described with reference to Figures 10 and 11. In this second embodiment, the configuration of a friction reducing portion 80 formed on a tip surface 72b of the cleaning blade 72 differs from that of the first embodiment described above. Since the other parts are similar, the same reference numbers are used for parts common to the first embodiment described above, and duplicated descriptions are omitted or simplified. Omission or simplification of duplicated descriptions is also applicable to other embodiments described below.

[0051] As shown in FIG. 10 and FIG. 11, the friction reduction portion 80 of the second embodiment is formed on the tip surface 72b of the cleaning blade 72 so that the contact area when it contacts the photosensitive drum 36 becomes smaller (i.e., the friction reduction effect becomes larger) as it moves away from the edge end 72a. In this embodiment, the number of recesses 80a formed is increased as it moves away from the edge end 72a, thereby reducing the contact area with the photosensitive drum 36 and increasing the friction reduction effect. This is because the friction force between the photosensitive drum 36 and the cleaning blade 72 becomes larger as the contact portion expands to a position away from the edge end 72a, and it is not necessary to reduce the friction force so much at a position relatively close to the edge end 72a. This makes it possible to reduce friction according to the magnitude of the friction force between the photosensitive drum 36 and the cleaning blade 72, and reduces the impact on the cleaning function of the cleaning blade 72 during normal use.

[0052] In the second embodiment, the same effects as in the first embodiment are achieved, and the simple configuration can appropriately prevent the cleaning blade 72 from turning over or reversing. In addition, since the contact area of ​​the friction reducing portion 80 with the photosensitive drum 36 decreases with increasing distance from the edge 72a, the effect on the cleaning function of the cleaning blade 72 during normal use can be more appropriately reduced.

[0053] [Third Example] 12 and 13, a cleaning blade 72 provided in a cleaning device 38 according to a third embodiment of this disclosure will be described. In the second embodiment described above, the number of recesses 80a formed increases with increasing distance from the edge end 72a, thereby reducing the contact area of ​​the friction reduction portion 80 with the photoconductor drum 36. In contrast, in the third embodiment, the size (opening diameter and depth) of the recesses 80a formed increases with increasing distance from the edge end 72a, thereby reducing the contact area of ​​the friction reduction portion 80 with the photoconductor drum 36.

[0054] The third embodiment also has the same advantageous effects as the first embodiment, and can appropriately prevent the cleaning blade 72 from turning over and reversing with a simple configuration. Also, like the second embodiment, it can more appropriately reduce the effect on the cleaning function of the cleaning blade 72 during normal use.

[0055] In the third embodiment described above, both the opening diameter and depth of the recess 80a are increased with increasing distance from the edge end 72a, but it is also possible to increase only one of the opening diameter and depth. By increasing the opening diameter of the recess 80a with increasing distance from the edge end 72a, the contact area of ​​the friction reduction portion 80 with the photosensitive drum 36 can be reduced, thereby increasing the friction reduction effect. On the other hand, by increasing the depth of the recess 80a with increasing distance from the edge end 72a, the contact pressure of the friction reduction portion 80 (recess 80a) with the photosensitive drum 36 can be reduced, thereby increasing the friction reduction effect.

[0056] [Fourth Example] Next, with reference to FIG. 14 and FIG. 15, the cleaning blade 72 provided in the cleaning device 38 according to the fourth embodiment of this disclosure will be described. In the first to third embodiments described above, the uneven friction reducing portion 80 is formed by forming the recesses 80a on the tip surface 72b of the cleaning blade 72. In contrast, in the fourth embodiment, the uneven friction reducing portion 80 including the recesses 80a and the protrusions 80b is formed by attaching a plurality of hemispherical protrusions 80b to the tip surface 72b of the cleaning blade 72 by the inkjet method. That is, the friction reducing portion 80 of this embodiment includes the protrusions 80b formed by the attachment portions. Specifically, the protrusions 80b can be formed by employing a method in which a UV ink material capable of permeating the cleaning blade 72 is ejected at a desired position on the tip surface 72b and cured by ultraviolet light.

[0057] In the fourth embodiment, the same effects as in the first embodiment are achieved, and the simple configuration can appropriately prevent the cleaning blade 72 from turning over and reversing. In addition, by forming the protrusions 80b by the attachment portion using the inkjet method, the friction reduction portion 80 can be easily formed on the tip surface 72b of the cleaning blade 72.

[0058] Furthermore, even when the convex portion 80b is formed by the adhesion portion, as in the second or third embodiment described above, the contact area of ​​the friction reduction portion 80 with the photosensitive drum 36 can be reduced as it moves away from the edge end 72a, and the depth of the concave portion 80a can be increased.

[0059] [Fifth Example] 16 and 17, a cleaning blade 72 provided in a cleaning device 38 according to a fifth embodiment of this disclosure will be described. In this fifth embodiment, a friction reducing portion 80 having an uneven shape including recesses 80a and protrusions 80b is formed by roughening the tip surface 72b of the cleaning blade 72 by polishing or the like. In the fifth embodiment, the size (opening diameter and depth) of the recesses 80a formed with increasing distance from the edge 72a is increased by changing the grit size of the file or abrasive, or by appropriately changing the processing conditions, thereby reducing the contact area of ​​the friction reducing portion 80 with the photoconductor drum 36.

[0060] The fifth embodiment also has the same advantageous effects as the first embodiment, and can appropriately prevent the cleaning blade 72 from turning over and reversing with a simple configuration. Also, like the second embodiment, it can more appropriately reduce the effect on the cleaning function of the cleaning blade 72 during normal use.

[0061] In the above embodiment, a multifunction machine combining a copier, a facsimile, a printer, etc., is exemplified as the image forming apparatus, but the image forming apparatus may be any one of a copier, a facsimile, a printer, etc., or a multifunction machine combining at least two of them. The image forming apparatus may also be a monochrome machine. Furthermore, the image forming apparatus is not limited to an intermediate transfer type, and may be a direct transfer type in which a toner image is directly transferred from a photosensitive drum to a sheet of paper.

[0062] It should be noted that the specific numerical values ​​and part shapes given above are merely examples and can be changed as appropriate according to the needs of product specifications, etc. [Explanation of symbols]

[0063] 10...Image forming device 12 ... Device body 30...Image forming section 36...Photosensitive drum (image carrier) 38 …Cleaning device 40 ... Charging device 60 ... Process unit 72 ... cleaning blade 72a … Edge end 72b…Tip surface P1 … Edge part P2 … Enlarged edge part 80 ... Friction reduction part 80a …recess 80b...Convex part

Claims

1. A cleaning device for removing residual toner from a surface of an image carrier, a cleaning blade that scrapes off toner remaining on the surface of the image carrier by contacting an edge portion of the tip side of the cleaning blade with the image carrier; The cleaning blade has an uneven friction reducing portion formed on a tip surface thereof.

2. The cleaning device according to claim 1 , wherein the friction reducing portion is formed on the tip surface at a portion upstream of the edge portion in the rotation direction of the image carrier.

3. 3. The cleaning device according to claim 2, wherein the friction reducing portion is formed at a portion of the tip surface at a distance of 50 [mu]m or more from the edge end of the edge portion.

4. The cleaning device according to claim 1 , wherein the friction reducing portion is formed at both longitudinal ends of the tip surface.

5. The cleaning device according to claim 4 , wherein the friction reducing portion is provided so as to include at least a portion of a region that is within a charging region and that is outside a developing region.

6. The cleaning device according to claim 5 , wherein the friction reducing portion is provided so as to include at least an end portion of the charging area.

7. 3. The cleaning device according to claim 1, wherein the friction reducing portion is formed so that a contact area when the friction reducing portion contacts the image carrier decreases with increasing distance from the edge end on the edge portion side.

8. 3. The cleaning device according to claim 1, wherein the friction reducing portion is formed so that the depth of the recess increases with increasing distance from the edge end on the edge portion side.

9. The cleaning device according to claim 1 , wherein the friction reducing portion includes a protrusion formed by an attachment portion.

10. Image carrier, a charging device for charging the surface of the image carrier; and 2. An image forming apparatus comprising the cleaning device according to claim 1, which removes toner remaining on the surface of the image bearing member.

Images