JP6287962B2 - Cleaning device and image forming apparatus - Google Patents

Description

  The present invention relates to a cleaning device for cleaning deposits such as toner remaining on the surface of an image carrier, and an image forming apparatus represented by a copying machine including the cleaning device.

  In an image forming apparatus such as a copying machine, a printer, or a facsimile machine, after a toner image is transferred to a sheet, a small amount of toner may remain on the surface of the image carrier without being transferred to the sheet. Deposits such as residual toner and paper dust on the surface of the image carrier obstruct the next new image formation, and therefore a cleaning process is required. As a method for cleaning an image carrier used for such a purpose, a method of scraping off deposits such as residual toner by bringing a blade member into contact with the surface of the image carrier is widely known.

  In recent years, in order to reduce downtime of an image forming apparatus, it has been required to extend the life of an image carrier or a blade member. It is the amount of wear that affects the life of the image carrier and the blade member, and the development of a cleaning device and an image forming apparatus in which wear is suppressed is being promoted.

  In order to suppress the wear of the image carrier and the blade member, it is an effective means to reduce the contact force with which the blade member is brought into contact with the image carrier. However, when the contact force is simply reduced, the cleaning performance of the toner by the blade member is lowered, and thus poor cleaning occurs. Therefore, it has been proposed to reduce the variation in the contact force. By reducing the variation in the contact force, the design center value of the contact force can be lowered, so that the life of the image carrier and the blade member can be extended.

  At present, the mainstream of cleaning devices is a blade member made of rubber having a strip shape (cuboid shape) attached to the tip of a blade holder made of a rigid body. The blade member is pressed against the image carrier to be elastically deformed, and the repulsive force is applied as a contact force. For this reason, if the physical properties and outer dimensions of the rubber and the dimensions of the blade holder vary, the contact force may fluctuate greatly. Patent Documents 1 and 2 disclose conventional techniques related to a cleaning device proposed to solve such a problem.

  In the cleaning device (cleaning device) described in Patent Document 1, the blade holder (leaf spring member) has flexibility. Since the blade holder (leaf spring member) has flexibility, a reaction force generated by its elastic deformation acts as a contact force. As a result, the contact force is not affected by variations in the physical properties and outer dimensions of the rubber that is the blade member, and fluctuations in the contact force are reduced.

  In the cleaning device (cleaning device) described in Patent Document 2, a flexible blade holder (support member) includes a bent portion between a holding portion of the blade member and a portion to be fixed to the casing. . As a result, when the frictional force fluctuates, the blade holder (supporting member) is not deformed on the blade member side relative to the bent portion, but is deformed on the fixed portion side rather than the bent portion, thereby suppressing the fluctuation of the contact force. doing.

JP 2008-102322 A JP 2013-050527 A

  FIG. 14 shows a schematic configuration of a conventional cleaning device described in Patent Document 1. The blade holder 133 of this conventional cleaning device is supported by a support portion 134 so that a predetermined contact force acts between the blade member 132 contacting the surface of the photosensitive drum 121 and the photosensitive drum 121, and bending stress is applied. Will occur. As a result, as shown in FIG. 14, a vertical drag N11 is generated at the contact portion of the blade member 132 with the photosensitive drum 121. When the photosensitive drum 121 rotates and the surface thereof moves in the rotation direction, a frictional force F11 is generated between the blade member 132 and the photosensitive drum 121. Further, a resultant force R11 of the frictional force F11 and the normal force N11 is generated in the blade member 132.

  FIG. 15 shows a state where a relatively large frictional force F12 is applied from the initial state shown in FIG. When the frictional force F12 is increased, the blade holder 133 is greatly curved, and the vertical drag N12 and the resultant force R12 are also increased from the beginning. In this way, the conventional cleaning device described in Patent Document 1 changes the deformation shape of the blade holder 133 when the frictional force generated between the blade member 132 and the photosensitive drum 121 changes. There is a possibility that the contact force between the blade member 132 and the photosensitive drum 121 may fluctuate. As a result, there is a problem that the wear amount of the blade member 132 and the photosensitive drum 121 increases.

  Further, since the blade holder 133 is greatly curved, the effective contact angle θ12 becomes smaller than the initial effective contact angle θ11. The effective contact angle is a factor that affects the cleanability of the surface of the photosensitive drum 121, and it is desirable to suppress the fluctuation in order to ensure stable cleanability.

  FIG. 16 shows a schematic configuration of a conventional cleaning device described in Patent Document 2. The blade holder 233 of this conventional cleaning device is supported by a support portion 234 so that a predetermined contact force acts between the blade member 232 that contacts the surface of the photosensitive drum 221 and the photosensitive drum 221, and bending stress Will occur. As a result, as shown in FIG. 16, a vertical drag N21 is generated at the contact portion of the blade member 232 with the photosensitive drum 221. When the photosensitive drum 221 rotates and the surface thereof moves in the rotation direction, a frictional force F21 is generated between the blade member 232 and the photosensitive drum 221. Further, a resultant force R21 of the frictional force F21 and the normal force N21 is generated in the blade member 232.

  FIG. 17 shows a state in which a relatively large frictional force F22 is applied from the initial state shown in FIG. When the frictional force F22 is increased, the blade holder 233 is not deformed on the blade member 232 side with respect to the bent portion, and is largely curved on the support portion 234 side with respect to the bent portion. As a result, the vertical drag N22 and the resultant force R22 are lower than the original. Thereby, the wear amount of the blade member and the image carrier can be reduced.

  However, in the conventional cleaning device described in Patent Document 2, the effective contact angle θ22 becomes larger than the initial effective contact angle θ21 due to the deformation form of the blade holder 233. As described above, the effective cleaning angle of this conventional cleaning device varies, and there is a risk that the cleaning performance is deteriorated and poor cleaning occurs. That is, the variation of the contact force can be suppressed, but the variation of the effective contact angle cannot be suppressed.

  In addition, the fluctuation of the frictional force is largely caused by a change in coverage (toner occupation ratio with respect to the paper surface) in image formation. Conventionally, by reducing the friction coefficient between the blade member and the image carrier, the frictional force is reduced to suppress wear of the blade member and the image carrier, and the adhesion force between the toner and the image carrier is reduced. In order to improve the cleaning performance by the blade member, a lubricant film is formed on the image carrier. As a simple method for supplying the lubricant to the surface of the image carrier, a method of externally adding the lubricant to the toner is often used. However, if image formation with relatively low coverage continues, the lubricant supplied to the surface of the image carrier together with the toner decreases, and the coefficient of friction on the surface of the image carrier increases. In this way, when the coverage varies, the friction coefficient of the surface of the image carrier changes, and the frictional force also varies.

  The present invention has been made in view of the above points, and provides a cleaning device and an image forming apparatus capable of reducing wear of a blade member and an image carrier and suppressing occurrence of poor cleaning. The purpose is to do.

In order to solve the above-described problems, a cleaning device of the present invention includes a blade member that contacts the surface of an image carrier and removes deposits on the surface, and a holding unit that is flexible and provided on one end side. A blade holder for holding the blade member, a support portion for supporting a supported portion provided on the opposite end side of the holding portion of the blade holder, and an image carrier provided on the support portion. The blade holder is configured to receive the supported portion of the blade holder from an opening facing the blade holder and to displace the supported portion as the blade member moves along the moving direction of the surface of the image carrier. An accommodating portion that supports the blade , and the accommodating portion includes an inclined portion that is configured by a curved surface that extends in a direction away from the surface of the image carrier as it goes toward the back with respect to the opening. The accommodating part Wherein the non-fixed.

  According to this configuration, the blade holder is supported by the receiving portion of the support portion so that it can be displaced as the blade member moves along the moving direction of the surface of the image carrier. Then, when the frictional force between the blade member and the image carrier varies with the variation of the friction coefficient on the surface of the image carrier, the blade holder displaces toward the back with respect to the opening of the housing portion. As a result, the length of the portion protruding outward from the opening of the blade holder, that is, the length corresponding to the free length of the cantilever is shortened, and the contact force and effective contact between the blade member and the image carrier are reduced. Angle fluctuation is suppressed.

  In the cleaning device having the above-described configuration, the housing portion includes an inclined portion that extends in a direction away from the surface of the image carrier as it goes toward the back with respect to the opening.

  Further, in the cleaning device having the above-described configuration, the inclined portion is configured by a surface.

  In the cleaning device having the above-described configuration, the blade holder includes a cylindrical surface at a tip of the supported portion.

  In the cleaning device having the above configuration, the opening extends in parallel with a direction in which the opening intersects the moving direction of the surface of the image carrier.

The cleaning device according to the present invention includes a blade member that contacts the surface of the image carrier and removes deposits on the surface, and a blade that holds the blade member with a flexible holding portion provided on one end side. A holding member, a supporting portion for supporting a supported portion provided on the opposite end side of the holding portion of the blade holding member, and an opening provided on the supporting portion and facing the image carrier. And a receiving portion that supports the blade holder so that the supported portion can be displaced as the blade member moves along the moving direction of the surface of the image carrier. , the length the receiving unit corresponding to the displacement direction of the blade holder is, than both end portions in the direction intersecting the moving direction of the surface of the image bearing member rather long towards the central portion, the blade holder is the accommodation Fixed to the part And wherein the not.

  Further, in the cleaning device having the above-described configuration, the blade holder and the housing portion engage with each other inside the housing portion to displace the blade holder in a direction crossing the moving direction of the surface of the image carrier. It is characterized by including an engaging portion for blocking.

  In the cleaning device having the above-described configuration, the engaging portion includes a convex portion and a concave portion that engage with each other.

  Further, in the cleaning device having the above-described configuration, the length of the concave portion in the direction intersecting the moving direction of the surface of the image carrier increases from the downstream side to the upstream side in the insertion direction of the blade holder into the housing portion. It is characterized by shortening.

  In the cleaning device having the above-described configuration, the length in the direction intersecting the moving direction of the surface of the image carrier of the blade holder or the housing portion is upstream of the insertion direction of the blade holder into the housing portion. It becomes shorter as it goes to the downstream side.

  According to the present invention, the cleaning device having the above-described configuration is mounted on an image forming apparatus.

  In the image forming apparatus having the above configuration, the image carrier is rotated in a direction opposite to that at the time of image formation before image formation.

  In the image forming apparatus having the above-described configuration, the length of the housing portion in the depth direction with respect to the opening is greater than the moving distance of the surface of the image carrier when the image carrier is rotated in the direction opposite to that during image formation. Characterized by its long length.

  In addition, the image forming apparatus having the above-described configuration includes a detection unit that detects a toner occupancy ratio with respect to the paper surface, and after forming an image on a document having a toner occupancy ratio lower than a predetermined value, the toner occupancy ratio is higher than a predetermined value. Before image formation on a document, the image carrier is rotated in the opposite direction to that during image formation.

  The image forming apparatus having the above configuration includes a detection unit that detects a toner occupancy ratio with respect to a paper surface, and switches from a document having a toner occupancy ratio lower than a predetermined value to a document higher than a predetermined value in the same image forming job. In addition, the image formation is temporarily stopped, and the image carrier is rotated in a direction opposite to that at the time of image formation.

  The image forming apparatus having the above-described configuration is an image forming apparatus capable of sequentially superimposing a plurality of color images, and includes a detection unit that detects a toner occupancy ratio with respect to a paper surface, and includes an upstream image color. When the toner occupancy of the toner becomes higher than a predetermined value, the image carrier is rotated in the direction opposite to that at the time of image formation.

  According to the configuration of the present invention, the blade holder can be displaced in accordance with the change in the frictional force between the blade member and the image carrier, and the contact force and effective contact between the blade member and the image carrier can be reduced. It becomes possible to suppress the variation of the contact angle. Therefore, wear of the blade member and the image carrier can be reduced, and occurrence of poor cleaning can be suppressed.

1 is a schematic partial vertical sectional front view of an image forming apparatus according to a first embodiment of the present invention. 1 is a schematic vertical sectional front view of an image forming unit of an image forming apparatus according to a first embodiment of the present invention. FIG. 2 is a vertical sectional front view of the cleaning device of the image forming apparatus according to the first embodiment of the present invention. FIG. 3 is a vertical sectional front view showing an engaging portion of the cleaning device of the image forming apparatus according to the first embodiment of the present invention. FIG. 3 is a partial cross-sectional perspective view showing an engaging portion of the cleaning device of the image forming apparatus according to the first embodiment of the present invention. FIG. 2 is a schematic view showing an engaging portion of the cleaning device of the image forming apparatus according to the first embodiment of the present invention, showing a state before the blade holder is attached to the support portion. FIG. 2 is a schematic view showing an engaging portion of the cleaning device of the image forming apparatus according to the first embodiment of the present invention, showing a state in the middle of attachment of the blade holder to the support portion. FIG. 2 is a schematic view showing an engaging portion of the cleaning device of the image forming apparatus according to the first embodiment of the present invention, and shows a state where the attachment of the blade holder to the support portion is completed. FIG. 3 is a vertical sectional front view illustrating a load state (F1 <N1) of the cleaning device of the image forming apparatus according to the first embodiment of the present invention. FIG. 3 is a vertical sectional front view showing a load state (F2> N2) of the cleaning device of the image forming apparatus according to the first embodiment of the present invention. FIG. 6 is a schematic view showing an engaging portion of a cleaning device of an image forming apparatus according to a second embodiment of the present invention, and shows a state in the middle of attachment of a blade holder to a support portion. FIG. 7 is a schematic view showing an engaging portion of a cleaning device of an image forming apparatus according to a second embodiment of the present invention, showing a state in which attachment of a blade holder to a support portion is completed. FIG. 9 is a schematic view showing an engaging portion of a cleaning device of an image forming apparatus according to a third embodiment of the present invention, showing a state before the blade holder is attached to the support portion. It is the schematic which shows the structure of the conventional cleaning apparatus (comparative example 1). It is the schematic which shows the state from which the frictional force was fluctuate | varied in the conventional cleaning apparatus (comparative example 1) of FIG. It is the schematic which shows the structure of the conventional cleaning apparatus (comparative example 2). It is the schematic which shows the state from which the frictional force was fluctuate | varied in the conventional cleaning apparatus (comparative example 2) of FIG.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings. The present invention is not limited to the following contents.

  First, an image output operation of the image forming apparatus according to the first embodiment of the present invention will be described while explaining the outline of the structure with reference to FIG. FIG. 1 is an example of a schematic partial vertical sectional front view of an image forming apparatus. In the figure, a two-dot chain line with an arrow indicates a sheet conveyance path and a conveyance direction.

  As shown in FIG. 1, the image forming apparatus 1 is a so-called tandem color copier, and includes an image reader unit 3 that reads an image of a document, a print unit 2 that prints the read image on a transfer material such as paper, And an operation display unit 4 for inputting printing conditions and displaying an operation status.

  The image reader unit 3 is a known unit that reads an image of a document placed on a platen glass (not shown) by moving a scanner. The image of the document is separated into three colors of red (R), green (G), and blue (B), and is converted into an electrical signal by a CCD (Charge Coupled Device) image sensor (not shown). Accordingly, the image reader unit 3 obtains image data for each color of red (R), green (G), and blue (B).

  The image data for each color obtained by the image reader unit 3 is subjected to various types of processing in the control unit 60, and is converted into image data for each reproduction color of yellow (Y), magenta (M), cyan (C), and black (K). It is converted and stored in a memory (not shown) in the control unit 60. The image data for each reproduction color stored in the memory is subjected to a process for correcting misregistration, and then is scanned for each scanning line in synchronism with the conveyance of the sheet in order to perform optical scanning on the photosensitive drum 21 which is an image carrier. Is read out.

  The printing unit 2 forms an image by electrophotography, and transfers the image onto a sheet or the like as a transfer material. The printing unit 2 includes an intermediate transfer belt 11 in which an intermediate transfer member is formed as an endless belt. The intermediate transfer belt 11 is applied with tension and is wound around the driving roller 12 and the driven roller 14. The intermediate transfer belt 11 is rotated by the driving roller 12 counterclockwise in FIG.

  The driving roller 12 is pressed and brought into contact with the secondary transfer roller 15 facing the intermediate transfer belt 11. At the position of the driven roller 14, an intermediate transfer cleaning unit 16 provided so as to face the driven roller 14 with the intermediate transfer belt 11 interposed therebetween contacts the outer peripheral surface of the intermediate transfer belt 11. The intermediate transfer cleaning unit 16 scrapes and cleans toner remaining on the outer peripheral surface of the intermediate transfer belt 11 after the secondary transfer.

  Below the intermediate transfer belt 11, image forming units 20Y, 20M, 20C, and 20K corresponding to reproduction colors of yellow (Y), magenta (M), cyan (C), and black (K) are provided. In this description, the “Y”, “M”, “C”, and “K” identification symbols are omitted and, for example, collectively referred to as “image forming unit 20” unless otherwise limited. There is. The four image forming units 20 are arranged in a line along the rotation direction of the intermediate transfer belt 11 from the upstream side to the downstream side in the rotation direction. The four image forming units 20 all have the same configuration, and a charging device 22, an exposure device (not shown), a developing device 23, and a cleaning device are arranged around the photosensitive drum 21 that rotates clockwise in FIG. 30 and a primary transfer roller 24 (see FIG. 2).

  Above the intermediate transfer belt 11, toner bottles 41 and toner hoppers 42 corresponding to the four image forming units 20 of each reproduction color are provided. When a decrease in the toner amount inside the developing device 23 is detected by the remaining amount detecting unit (not shown), the replenishing device (not shown) is driven to replenish the toner from the toner hopper 42 to the developing device 23. Further, when a decrease in the amount of toner inside the toner hopper 42 is detected by the remaining amount detection unit (not shown), the replenishing device (not shown) is driven to replenish toner from the toner bottle 41 to the toner hopper 42. . The toner bottle 41 is detachably attached to the apparatus main body, and can be replaced with a new one as appropriate.

  A paper feed cassette 51 is provided below the four image forming units 20, and a transfer material such as paper is accommodated therein. The paper stored in the paper feed cassette 51 is sent out to the paper transport path P in order from the uppermost layer by the paper feed roller 52. The sheet fed from the sheet feeding cassette 51 to the sheet conveyance path P reaches the position of the pair of registration rollers 53a and 53b. Then, in synchronization with the rotation of the intermediate transfer belt 11, the registration roller pairs 53 a and 53 b send out the sheet toward the contact portion (secondary transfer nip portion) between the intermediate transfer belt 11 and the secondary transfer roller 15.

  In the image forming unit 20, an electrostatic latent image is formed on the surface of the photosensitive drum 21 by the charging device 22 and the exposure device, and the electrostatic latent image is visualized as a toner image by the developing device 23. The toner image formed on the surface of the photosensitive drum 21 is primarily transferred onto the outer peripheral surface of the intermediate transfer belt 11 at a location where the photosensitive drum 21 faces the primary transfer roller 24 with the intermediate transfer belt 11 interposed therebetween. The toner images of the image forming units 20 are sequentially transferred to the intermediate transfer belt 11 at a predetermined timing along with the rotation of the intermediate transfer belt 11, so that yellow, magenta, cyan, black on the outer peripheral surface of the intermediate transfer belt 11. A color toner image is formed by superimposing the four color toner images.

  The color toner image primarily transferred to the outer peripheral surface of the intermediate transfer belt 11 is formed by contacting the intermediate transfer belt 11 and the secondary transfer roller 15 on a sheet sent in synchronization by a pair of registration rollers 53a and 53b. Is transferred at the secondary transfer nip portion.

  A fixing portion 55 is provided above the secondary transfer nip portion. The sheet on which the unfixed toner image is transferred at the secondary transfer nip is sent to the fixing unit 55 and is sandwiched between the heat roller and the pressure roller, and the toner image is heated and pressed to be fixed on the sheet. The sheet that has passed through the fixing unit 55 is discharged to a sheet discharge unit 56 provided above the intermediate transfer belt 11.

  Next, the configuration and operation of the image forming unit 20 of the image forming apparatus 1 will be described with reference to FIGS. 2 to 8 in addition to FIG. FIG. 2 is a schematic vertical sectional front view of the image forming unit 20. FIG. 3 is a vertical sectional front view of the cleaning device 30. 4 and 5 are a vertical sectional front view and a partial sectional perspective view showing an engaging portion of the cleaning device 30. 6, 7, and 8 are schematic views showing the engaging portion of the cleaning device 30, showing a state before the blade holder is attached to the support portion, and in the process of being attached to the support portion of the blade holder. It shows the state and the state where the attachment of the blade holder to the support portion is completed. 3 and 4 are cross-sectional views of different portions in the axial direction of the photosensitive drum 21. 6, 7 and 8 show a part of the cleaning device 30 viewed from the photosensitive drum 21 side.

  As described above, since the four color image forming units 20 have the same structure, the identification symbols “Y”, “M”, “C”, and “K” are omitted. In this description, the direction of the axis of the photosensitive drum 21, that is, the direction crossing the moving direction of the surface of the photosensitive drum 21 serving as an image bearing member is the X direction shown in FIGS. 2 and 3 (FIGS. 2 and 3). The direction in which the blade holder 33 (to be described later) is displaced as the blade member 32 moves is the Y direction described in FIGS. 2 and 3. Hereinafter, the X direction and the Y direction may be used in other descriptions.

  As shown in FIG. 2, the image forming unit 20 includes a photosensitive drum 21 as an image carrier at the center thereof. In the vicinity of the photosensitive drum 21, a charging device 22, a developing device 23, and a cleaning device 30 are sequentially arranged along the rotation direction. The primary transfer unit 24 is provided between the developing device 23 and the cleaning device 30 along the rotation direction of the photosensitive drum 21. A neutralizing device (not shown) is disposed downstream of the cleaning device 30 in the rotation direction of the photosensitive drum 21.

  The photosensitive drum 21 extends in the paper width direction perpendicular to the paper conveyance direction of the image forming apparatus 1, that is, the paper surface depth direction in FIGS. 1 and 2, and is arranged with its axis direction horizontal. The photosensitive drum 21 is an inorganic photosensitive drum in which a photosensitive layer of an inorganic photoconductive material is provided on the outside of a conductive roller-shaped substrate made of, for example, aluminum. The photosensitive drum 21 is rotated by a driving device (not shown) so that the peripheral speed thereof is substantially the same as the paper conveyance speed.

  The charging device 22 includes a charging roller 22 a that contacts the photosensitive drum 21. The charging roller 22 a contacts the photosensitive drum 21 with a predetermined pressure, and rotates according to the rotation of the photosensitive drum 21. By this charging roller 22a, the surface of the photosensitive drum 21 is uniformly charged with a predetermined negative polarity potential.

  The exposure device 22 irradiates the surface of the photosensitive drum 21 with a laser beam L or the like modulated based on image data to be formed. As a result, the potential charged by the charging device 22 is partially attenuated and an electrostatic latent image of the original image is formed.

  The developing device 23 includes a developing sleeve 23b and a stirring circulation screw 23c inside the developing tank 23a. The developing sleeve 23 b is disposed so that the peripheral surface thereof faces the peripheral surface of the photosensitive drum 21. The agitation and circulation screw 23c agitates and circulates the carrier and toner inside the developing tank 23a, and supplies the toner to the peripheral surface of the developing sleeve 23b. The developing device 23 is charged with toner, which is a developer, and is supplied to the electrostatic latent image on the surface of the photosensitive drum 21 to develop the electrostatic latent image.

  The developing device 23 uses, for example, a two-component toner obtained by mixing a magnetic carrier and a nonmagnetic toner as a developer. Further, a lubricant as an external additive is mixed in the toner. As the lubricant, for example, inorganic stearic acid compound fine particles such as zinc stearate fine particles and aluminum stearate fine particles are employed, and one or more of these can be used in combination. The lubricant moves to the surface of the photosensitive drum 21 to form a lubricant film. When the lubricant film is formed, the friction coefficient of the surface of the photosensitive drum 21 is reduced. As a result, the frictional force acting between the photosensitive drum 21 and a blade member 32 of the cleaning device 30 described later is reduced, and wear of the photosensitive drum 21 and the blade member 32 can be reduced. In addition, the adhesion force acting between the toner and the photosensitive drum 21 is reduced, and the cleaning performance of the toner by the cleaning device 30 is improved. By these actions, the life of the photosensitive drum 21 and the cleaning device 30 is extended.

  The primary transfer unit 24 is provided with a primary transfer roller 24 a that contacts the photosensitive drum 21 with the intermediate transfer belt 11 interposed therebetween. The primary transfer roller 24 a contacts the intermediate transfer belt 11 with a predetermined pressure and rotates according to the rotation of the intermediate transfer belt 11. Further, a primary transfer bias having a polarity different from the charging polarity of the photosensitive drum 21 and the toner is applied to the primary transfer roller 24a as necessary.

  The static eliminator is disposed on the downstream side of the cleaning device 30 along the rotation direction of the photosensitive drum 21. The static eliminator includes a plurality of LEDs (Light Emitting Diodes) arranged in the axial direction of the photosensitive drum 21 (X direction in FIG. 3). The static eliminator irradiates the photosensitive drum 21 with the neutralizing light of the LED to remove the charged charge on the surface thereof, erases the electrostatic latent image, and prepares for the charging process in the next image forming operation.

  As shown in FIG. 3, the cleaning device 30 includes a blade member 32, a blade holder 33, a support portion 34, and a discharge screw 35 in a housing 31.

  The blade member 32 is held by a blade holder 33 and is disposed so as to contact the surface of the photosensitive drum 21. The blade member 32 is made of, for example, polyurethane rubber molded in a rectangular parallelepiped shape, and extends along the axial direction of the photosensitive drum 21 (X direction in FIG. 3) and has substantially the same length as the photosensitive drum 21. The blade member 32 is attached to the blade holder 33 by using, for example, a hot-melt adhesive, and the rectangular portion of the rectangular parallelepiped contacts the surface of the photosensitive drum 21. The blade member 32 removes adhering matter such as residual toner on the surface of the photosensitive drum 21 so as to scrape off.

  The blade holder 33 is supported by a support portion 34 provided in the housing 31. The blade holder 33 is formed as a flexible plate member made of metal, for example, and extends along the axial direction of the photosensitive drum 21. Further, the blade holder 33 has a flat portion of the plate inclined at a predetermined angle with respect to the surface of the photosensitive drum 21, while the blade member 32 contacts the photosensitive drum 21 with respect to the contact portion of the photosensitive drum 21. From the support portion 34 located on the downstream side in the rotation direction, it extends toward the photosensitive drum 21 so as to be substantially opposite to the moving direction of the surface of the photosensitive drum 21. As the metal constituting the blade holder 33, a strip plate of spring steel, stainless steel, brass, phosphor bronze, beryllium copper or the like is used.

  The blade holder 33 has a blade holder 33 a to which the blade member 32 is attached on one end side close to the photosensitive drum 21. On the other hand, a supported portion 33 b, which is a portion where the blade holding body 33 is supported by the support portion 34, is provided on the opposite end side of the blade holding portion 33 a of the blade holding body 33. The blade holder 33 is supported by the support portion 34 so that a predetermined contact force acts between the blade member 32 that contacts the surface of the photosensitive drum 21 and the photosensitive drum 21. A cylindrical surface 33c having an axial line extending in parallel along the axial direction of the photosensitive drum 21 (X direction in FIG. 3) is formed at the tip of the supported portion 33b.

  The support portion 34 is formed in the housing 31 and is provided with a storage portion 36 that supports the blade holder 33. The accommodating portion 36 is formed as a space for accommodating the supported portion 33b of the blade holder 33, and includes an opening 36a, a first surface 36b, a second surface 36c, and an inclined portion 36d.

  The opening 36 a is disposed at a location where the accommodating portion 36 faces the photosensitive drum 21. The opening 36a has a rectangular shape and extends in parallel along the axial direction of the photosensitive drum 21 (X direction in FIG. 3). The opening 36 a has a size that ensures a slight margin around the blade holder 33 in the axial direction of the photosensitive drum 21 (X direction in FIG. 3) and the thickness direction of the blade holder 33.

  The supported portion 33b of the blade holder 33 is inserted into the accommodating portion 36 through the opening 36a and accommodated. The accommodating portion 36 supports the blade holder 33 so that the supported portion 33b can be displaced along the Y direction in FIG. 3 as the blade member 32 moves along the moving direction of the surface of the photosensitive drum 21. To do.

  The accommodating portion 36 includes a first surface 36b and a second surface 36c extending toward the back side with respect to the opening 36a. The first surface 36b forms one inner surface on the side close to the photosensitive drum 21 with respect to the internal space of the accommodating portion 36, and the second surface 36c is the side away from the photosensitive drum 21 with respect to the internal space of the accommodating portion 36. Forming one inner surface. The length of the second surface 36c is longer than the length of the first surface 36b with respect to the length extending toward the back side with respect to the opening 36a of the accommodating portion 36. The accommodating portion 36 is formed so that the first surface 36b and the second surface 36c are separated from each other toward the back side with respect to the opening 36a, and the space is widened.

  The inclined portion 36d is a back portion of the accommodating portion 36 with respect to the opening 36a, and is formed between the first surface 36b and the second surface 36c. The inclined portion 36b is curved so as to protrude outward from the first surface 36b side to the second surface 36c side in a direction away from the surface of the photosensitive drum 21 as it goes to the back side with respect to the opening 36a. Consists of extending surfaces.

  Further, as shown in FIGS. 4 and 5, an engaging portion 37 is provided inside the accommodating portion 36. The engaging portion 37 includes a convex portion 37a and a concave portion 37b that engage with each other. The convex portion 37 a is formed in the accommodating portion 36, and the concave portion 37 b is formed in the supported portion 33 b of the blade holder 33. As shown in FIG. 6, the convex portions 37 a and the concave portions 37 b are arranged at two places with a predetermined interval in the axial direction of the photosensitive drum 21 (the X direction in FIG. 6).

  The convex portion 37a has a pin shape with a circular cross-section straddling between the first surface 36b and the second surface 36c of the accommodating portion 36. The concave portion 37b is disposed at a position corresponding to the convex portion 37a, and has a notch shape that is recessed from the distal end side of the supported portion 33b toward the blade member 32 side.

  Of the two concave portions 37b, one concave portion 37b is provided with a slope portion 37c and a fitting portion 37d. The inclined surface portion 37c has an inclination in which the interval becomes narrower from the distal end side of the supported portion 33b toward the blade member 32 side. The fitting portion 37d further extends toward the blade member 32 from the portion where the interval between the slope portions 37c is the narrowest. The length of the fitting portion 37d in the axial direction (X direction in FIG. 6) of the photosensitive drum 21 is substantially the same as the outer diameter of the convex portion 37a. That is, the length of the recess 37 b provided in the blade holder 33 in the direction intersecting the moving direction of the surface of the photosensitive drum 21 is from the downstream side to the upstream side in the insertion direction of the blade holder 33 into the housing portion 36. Shorter as you follow. The other concave portion 37b is configured such that the length of the photosensitive drum 21 in the axial direction (the X direction in FIG. 6) is longer than the outer diameter of the convex portion 37a.

  As described above, FIG. 6 shows a state before the blade holder 33 is attached to the support portion 34. When the blade holder 33 is inserted into the accommodating portion 36 of the support portion 34, as shown in FIG. 7, the slope portion 37c of one of the concave portions 37b contacts the peripheral surface of the convex portion 37a disposed at a location corresponding to the concave portion 37b. To do. Further, when the insertion of the blade holder 33 into the accommodating portion 36 is advanced, the blade holder 33 moves along the slope of the slope portion 37c, and the convex portion 37a is fitted in the final stage of insertion as shown in FIG. It fits into the part 37d. In this way, the position of the blade holder 33 with respect to the axial direction (X direction in FIGS. 6 to 8) of the photosensitive drum 21 in the housing portion 36 is determined, and displacement of the blade holder 33 in that direction is prevented. Is done.

  The discharge screw 35 is disposed inside the housing 31 with a portion where the blade member 32 is disposed with respect to the photosensitive drum 21 (see FIG. 3). The discharge screw 35 conveys and discharges the deposits such as residual toner removed by the blade member 32 from the surface of the photosensitive drum 21 to the outside of the housing 31. Deposits on the surface of the photosensitive drum 21 discharged from the cleaning device 30 are transported to a waste toner box (not shown) and collected.

  Then, the effect | action of the cleaning apparatus 30 is demonstrated using FIG.9 and FIG.10. 9 is a vertical sectional front view showing a load state (F1 <N1) of the cleaning device 30, and FIG. 10 is a vertical sectional front view showing a load state (F2> N2) of the cleaning device 30.

  The blade holder 33 of the cleaning device 30 is supported by the support portion 34 so that a predetermined contact force acts between the blade member 32 that contacts the surface of the photosensitive drum 21 and the photosensitive drum 21, and bending stress is generated. To do. As a result, as shown in FIG. 9, a vertical drag N <b> 1 is generated at the contact portion of the blade member 32 with the photosensitive drum 21. When the photosensitive drum 21 rotates and its surface moves in the rotation direction, a frictional force F <b> 1 is generated between the blade member 32 and the photosensitive drum 21. Further, the blade member 32 generates a resultant force R1 of the frictional force F1 and the normal force N1.

  When the frictional force F1 <the vertical drag N1, the blade holder 33 takes the form of a lever with the position of the opening 36a of the accommodating portion 36 as a fulcrum as shown in FIG. In other words, the supported portion 33 b of the blade holder 33 is in contact with the first surface 36 b of the storage portion 36 inside the storage portion 36. Accordingly, the position in the direction in which the blade holder 33 is displaced as the blade member 32 moves (the Y direction in FIG. 9 and the depth direction with respect to the opening 36a of the housing portion 36) is determined.

  On the other hand, when the friction coefficient of the surface of the photosensitive drum 21 is increased and the frictional force F2> the vertical drag N2 is satisfied, the blade holder 33 uses the position of the opening 36a of the housing portion 36 as a fulcrum as shown in FIG. Forms like a lion. In other words, the supported portion 33 b of the blade holder 33 is in contact with the second surface 36 c of the storage portion 36 inside the storage portion 36. As a result, the position in the direction in which the blade holder 33 is displaced as the blade member 32 moves (the Y direction in FIG. 10, the depth direction with respect to the opening 36 a of the housing portion 36) is determined.

  As described above, since the fulcrum of the blade holder 33 differs depending on the magnitude of the frictional force and the normal force, the positional accuracy of the opening 36a of the housing portion 36 is important. As shown in FIG. 10, when the blade holder 33 is displaced toward the back side of the housing portion 36, the length of the portion protruding outward from the opening 36a, that is, the length corresponding to the free length of the cantilever is shortened. . With respect to the cantilever beam, the effective contact angle related to the contact between the blade member 32 and the photosensitive drum 21 is expressed by the following formula (1).

Formula (1) φ = φ0−arctan (3 × Δu / 2 / L)
(In the formula, φ represents the effective contact angle, φ0 represents the contact angle, Δu represents the amount of biting, and L represents the free length of the cantilever beam.)

  According to equation (1), it can be seen that the effective contact angle φ decreases as the free length L of the cantilever decreases.

  In this way, the cleaning device 30 can suppress fluctuations in the contact force and the effective contact angle even when the frictional force related to the contact between the blade member 32 and the photosensitive drum 21 varies. Become. Further, when the blade holder 33 moves toward the inner side of the housing portion 36, the amount of biting is reduced, so that the vertical drag is reduced and the resultant force of the frictional force and the vertical drag is also reduced.

  In addition, the inclined portion 36 d of the housing portion 36 is configured by a curved surface, and a cylindrical surface 33 c is formed at the tip of the supported portion 33 b of the blade holder 33. As a result, the fulcrum position is switched from the state shown in FIG. 9 to the state shown in FIG. 10 with good sensitivity with respect to the displacement of the blade holder 33 accompanying the fluctuation of the frictional force. Note that the shape of the curved surface of the inclined portion 36d is most effective when the following expression (2) is satisfied.

Expression (2) L = (E × Δu × t3 × (μ + 1) / 4 / F2) (1/3)
(In the formula, L represents the free length, E represents the Young's modulus, Δu represents the amount of biting, t represents the thickness of the blade holder 33, μ represents the coefficient of friction, and F represents the contact force) .)

  Further, since the opening 36 a of the housing portion 36 extends in parallel along the axial direction of the photosensitive drum 21, the contact force acting between the blade member 32 and the photosensitive drum 21 in the axial direction of the photosensitive drum 21 is photosensitive. It becomes uniform with respect to the axial direction of the body drum 21.

  The image forming apparatus 1 may rotate the photosensitive drum 21 in a direction opposite to that during image formation (counterclockwise in FIGS. 2 and 3) before image formation. By rotating the photosensitive drum 21 in the direction opposite to that at the time of image formation, the blade holder 33 that comes into contact with the surface of the photosensitive drum 21 via the blade member 32 is displaced in the direction of being pulled out from the accommodating portion 36. As a result, the position of the blade holder 33 in the direction of displacement with the movement of the blade member 32 (depth direction with respect to the opening 36a of the accommodating portion 36) is appropriately reset.

  The length in the depth direction with respect to the opening 36a of the accommodating portion 36 is longer than the moving distance of the surface of the photosensitive drum 21 when the photosensitive drum 21 is rotated in the direction opposite to that during image formation. This prevents the blade holder 33 from falling out of the housing portion 36 when the photosensitive drum 21 is rotated in the direction opposite to that during image formation.

  Here, the image forming apparatus 1 includes a detection unit 61 that detects coverage (toner occupancy with respect to the paper surface) in image formation as shown in FIG. The detection unit 61 can detect coverage in image formation from the input document image data.

  As described above, when the coverage in image formation is relatively low, the friction coefficient of the surface of the photosensitive drum 21 is high (the state shown in FIG. 10), and when the coverage is relatively high, the friction coefficient of the surface of the photosensitive drum 21 is low. (State shown in FIG. 9). Therefore, after the image forming apparatus 1 forms an image with respect to a document whose coverage is lower than a predetermined value and before forming an image with respect to a document whose coverage is higher than a predetermined value, the photosensitive drum 21 is reversed from the time of image formation. Rotate in the direction to reset the position of the blade holder 33 appropriately.

  Further, the image forming apparatus 1 starts from a document whose coverage is lower than a predetermined value (for example, 2%) in a same image forming job, that is, while a plurality of images are continuously formed. When the original is higher than 5%), the image formation is temporarily stopped and the photosensitive drum 21 is rotated in the direction opposite to that at the time of image formation. Thereby, the position of the blade holder 33 is suitably reset.

  When the number of printed sheets from the change in coverage to the change in the coefficient of friction of the surface of the photosensitive drum 21 is confirmed by an image forming apparatus bizhub (registered trademark) C554e manufactured by Konica Minolta, it is about 100 sheets of A4 size paper. there were. Accordingly, it is preferable that the photosensitive drum 21 is rotated in the direction opposite to that at the time of image formation within 100 sheets of A4 size paper.

  Further, in the case of an image forming apparatus capable of sequentially superimposing a plurality of color images as in the image forming apparatus 1, the upstream color in the rotation direction of the intermediate transfer belt 11, that is, yellow ( It has been confirmed that the reverse transfer toner of Y) reaches the cleaning device 30 and polishes the lubricant film on the surface of the photosensitive drum 21 by the cleaning device 30. Thus, when the color coverage of the upstream image becomes higher than a predetermined value (for example, 20%), it is preferable to rotate the photosensitive drum 21 in the direction opposite to that at the time of image formation.

  Next, with regard to the present embodiment, the evaluation of the cleanability, blade member wear, and photoreceptor drum wear of the image forming apparatuses of the examples and the comparative example will be described.

  In the example, the image forming apparatus bizhub (registered trademark) C554e manufactured by Konica Minolta Co., Ltd. was used to form the cleaning device 30 of the above embodiment. The image forming apparatus of Comparative Example 1 includes a cleaning device (cleaning device) described in Patent Document 1. The image forming apparatus of Comparative Example 2 includes a cleaning device (cleaning device) described in Patent Document 2.

  Prior to the evaluation, zinc stearate was used as a lubricant to be externally added to the toner, and each color coverage of 25%, 5% and 1% of an original was printed on A4 size paper in an environment of 23 ° C. and humidity 65% RH. Printed. Thereafter, the cleaning property, the abrasion of the blade member, and the abrasion of the photosensitive drum were evaluated.

  Regarding the cleanability, in an environment where the temperature is 10 ° C. and the humidity is 15% RH, when the front half of A3 size paper is printed as a solid black image and the back half is printed as a solid white image, the image indicates whether or not there is a cleaning failure. confirmed. Judgment was made ◯ when no cleaning failure occurred, △ when a minor cleaning failure occurred, and × when a severe cleaning failure occurred.

  Regarding the wear of the blade member, a cross-sectional profile was created by VK9500 manufactured by Keyence Corporation, and the wear width was measured. The determination was made by observing the entire axial direction of the photosensitive drum, ◯ when the maximum wear width was less than 5 μm, Δ when it was 5 μm or more and less than 10 μm, and × when it was 10 μm or more.

  Regarding the abrasion of the photosensitive drum, the film thickness was measured by attaching an eddy current type probe to FischerSCOPE (registered trademark) manufactured by Fischer, and the film thickness difference before and after printing 100,000 sheets was calculated. In the judgment, when the wear amount was less than 10 μm, ◯, when 10 μm or more and less than 15 μm, Δ, and when 15 μm or more, ×.

  According to Table 1, it can be confirmed that the cleaning device of the example does not cause poor cleaning regardless of the coverage ratio, and that the wear of the blade member and the photosensitive drum satisfies a satisfactory level. did it.

  On the other hand, about the cleaning apparatus of the comparative example 1, it has confirmed that there was no problem in quality in coverage 25%. However, it was confirmed that when the coverage was 5%, severe cleaning failure occurred and the wear of the blade member and the photosensitive drum increased slightly. Furthermore, it was confirmed that at the coverage of 1%, the wear of the blade member and the photosensitive drum was also greatly increased.

  Moreover, about the cleaning apparatus of the comparative example 2, it has confirmed that there was no problem in quality in coverage 25%. However, at a coverage of 5%, a satisfactory level of wear of the blade member and the photosensitive drum was satisfied, but it was confirmed that a minor cleaning failure occurred. Furthermore, it was confirmed that the poor cleaning was severe at a coverage of 1%.

Second Embodiment
Next, an image forming apparatus according to a second embodiment of the present invention will be described with reference to FIGS. 11 and 12 are schematic views showing the engaging portion of the cleaning device of the image forming apparatus, showing a state in the middle of attachment of the blade holder to the support portion, and the attachment of the blade holder to the support portion being completed. This shows the state. 11 and 12 show a part of the cleaning device viewed from the photosensitive drum side. Since the basic configuration of this embodiment is the same as that of the first embodiment described above, the same components as those of the first embodiment are denoted by the same reference numerals and the description thereof is omitted. And

  In the image forming apparatus 1 according to the second embodiment, the engaging portion 37 of the cleaning device 30 includes a slope portion 37e as shown in FIGS. The slope portions 37e are formed at both ends of the supported portion 33b of the blade holder 33 in the axial direction of the photosensitive drum 21 (X direction in FIGS. 11 and 12). The slope portion 37e is formed such that the length of the photosensitive drum 21 in the axial direction becomes shorter from the blade member 32 side toward the tip end side of the supported portion 33b. That is, the slope portion 37e has a length in a direction intersecting the moving direction of the surface of the photosensitive drum 21 of the blade holder 33 as it goes from the upstream side to the downstream side in the insertion direction of the blade holder 33 into the housing portion 36. It is formed to be shorter.

  When the blade holder 33 is inserted into the accommodating portion 36 of the support portion 34, as shown in FIG. 11, one inclined surface portion 37e comes into contact with the wall portion of the accommodating portion 36 on the side corresponding to the inclined surface portion 37e. Further, when the insertion of the blade holder 33 into the accommodating portion 36 is advanced, the blade holder 33 moves along the slope of the slope portion 37e, and the blade holder 33 is covered in the final stage of insertion as shown in FIG. The support portion 33b is fitted into the storage portion. In this way, the position of the blade holder 33 with respect to the axial direction (X direction in FIGS. 11 and 12) of the photosensitive drum 21 of the housing portion 36 is determined, and displacement of the blade holder 33 in that direction is prevented. Is done.

  The inclined portion 37e is formed in the housing portion 36, and the length of the housing portion 36 in the direction intersecting the moving direction of the surface of the photosensitive drum 21 is the upstream side in the insertion direction of the blade holder 33 into the housing portion 36. You may make it become short as it goes to the downstream side.

<Third Embodiment>
Next, an image forming apparatus according to a third embodiment of the present invention will be described with reference to FIG. FIG. 13 is a schematic view showing an engaging portion of the cleaning device of the image forming apparatus, and shows a state before the blade holder is attached to the support portion. FIG. 13 shows a part of the cleaning device viewed from the photosensitive drum side. Since the basic configuration of this embodiment is the same as that of the first embodiment described above, the same components as those of the first embodiment are denoted by the same reference numerals and the description thereof is omitted. And

  In the image forming apparatus 1 according to the third embodiment, as illustrated in FIGS. 11 and 12, the housing portion 36 of the cleaning device 30 includes an opening 36 e. The opening 36e is curved with respect to the axial direction of the photosensitive drum 21 (X direction in FIG. 13) so that the central portion protrudes toward the outside of the housing portion 36. In other words, the accommodating portion 36 has a length corresponding to the displacement direction of the blade holder 33 (depth of the accommodating portion 36) from both ends (D2 in FIG. 13) in a direction intersecting the moving direction of the surface of the photosensitive drum 21. Is longer in the center (D1 in FIG. 13).

  In the case where the strength of the support portion 34 cannot be obtained sufficiently, the housing portion 36 is greatly deformed in the central portion as compared with both end portions of the photosensitive drum 21 in the axial direction, and sufficient vertical drag cannot be applied. There is. Therefore, according to the configuration of the third embodiment, since the opening 36e of the accommodating portion 36 is curved as described above, the blade holder 33 is free at the central portion with respect to both end portions in the axial direction of the photosensitive drum 21. The length is shortened, and fluctuations in the contact force between the blade member 32 and the photosensitive drum 21 can be suppressed.

  As in the first, second, and third embodiments, the cleaning device 30 of the image forming apparatus 1 includes a blade member 32 that contacts the surface of the photosensitive drum 21 and removes deposits on the surface of the photosensitive drum 21. A blade holding body 33 having flexibility and holding the blade member 32 by a blade holding portion 33a provided on one end side, and a supported portion 33b provided on the opposite end side of the blade holding portion 33a of the blade holding body 33. And a supported portion 33b of the blade holder 33 through an opening 36a provided on the support portion 34 and facing the photosensitive drum 21, and the blade member 32 moves in the moving direction of the surface of the photosensitive drum 21. And an accommodating portion 36 that supports the blade holder 33 so that the supported portion 33b can be displaced as it moves along.

  According to this configuration, the blade holder 33 is supported by the housing portion 36 of the support portion 34 so that the blade member 32 can be displaced as the blade member 32 moves along the moving direction of the surface of the photosensitive drum 21. When the frictional force between the blade member 32 and the photosensitive drum 21 varies with the variation of the friction coefficient on the surface of the photosensitive drum 21, the blade holder 33 is moved to the rear side with respect to the opening 36 a of the housing portion 36. Can be displaced toward. As a result, the length of the portion of the blade holder 33 protruding outward from the opening 36a, that is, the length corresponding to the free length of the cantilever is shortened, and the contact force between the blade member 32 and the photosensitive drum 21 is reduced. And it becomes possible to suppress the fluctuation | variation of an effective contact angle. Therefore, even when the frictional force between the blade member 32 and the photosensitive drum 21 varies, the wear of the blade member 32 and the photosensitive drum 21 can be reduced, and the occurrence of poor cleaning can be suppressed. It becomes possible.

  Further, the accommodating portion 36 includes an inclined portion 36d extending in a direction away from the surface of the photosensitive drum 21 toward the back side with respect to the opening 36a. The inclined portion 36d is formed of a curved surface. Further, the blade holder 33 includes a cylindrical surface 33c at the tip of the supported portion 33b.

  According to these configurations, the fulcrum position at the position of the opening 36a of the housing portion 36 is changed from the state shown in FIG. 9 to the state shown in FIG. It becomes possible to switch. Therefore, fluctuations in the contact force and effective contact angle between the blade member 32 and the photosensitive drum 21 can be effectively suppressed.

  The accommodating portion 36 extends in parallel along the direction in which the opening 36 a intersects the moving direction of the surface of the photosensitive drum 21, that is, the axial direction of the photosensitive drum 21.

  According to this configuration, the contact force acting between the blade member 32 and the photosensitive drum 21 in the axial direction of the photosensitive drum 21 can be made uniform in the axial direction of the photosensitive drum 21.

  In the image forming apparatus 1 according to the third embodiment, the length of the housing portion 36 corresponding to the displacement direction of the blade holder 33 (depth of the housing portion 36) intersects the moving direction of the surface of the photosensitive drum 21. The central portion (D1 in FIG. 13) is longer than both ends (D2 in FIG. 13) in the direction, that is, the axial direction of the photosensitive drum 21.

  According to this configuration, both ends of the blade holder 33 in the axial direction of the photosensitive drum 21 even when the housing portion 36 is greatly deformed in the central portion as compared with both ends in the axial direction of the photosensitive drum 21. On the other hand, the free length can be shortened in the central portion. As a result, it is possible to suppress fluctuations in the contact force between the blade member 32 and the photosensitive drum 21.

  Further, in the image forming apparatus 1, the blade holder 33 and the accommodating portion 36 are engaged with each other inside the accommodating portion 36 and intersect the moving direction of the surface of the photosensitive drum 21, that is, in the axial direction of the photosensitive drum 21. An engagement portion 37 that prevents the displacement of the blade holder 33 is provided.

  According to this configuration, the position of the blade holder 33 with respect to the axial direction of the photosensitive drum 21 in the housing portion 36 can be determined. Thereby, the blade member 32 can be brought into contact with an appropriate position on the surface of the photosensitive drum 21.

  The engaging portion 37 includes a convex portion 37a and a concave portion 37b that engage with each other.

  According to this configuration, determination of the position of the blade holder 33 with respect to the axial direction of the photosensitive drum 21 in the housing portion 36 and prevention of displacement of the blade holder 33 in that direction can be realized with a simple structure. Is possible.

  In the image forming apparatus 1 of the first embodiment, the length of the surface of the photosensitive drum 21 in the concave portion 37b in the axial direction is from the downstream side to the upstream side in the insertion direction of the blade holder 33 into the housing portion 36. Shorter as you follow. Further, in the image forming apparatus 1 of the second embodiment, the length of the blade holder 33 in the axial direction of the photosensitive drum 21 is from the upstream side to the downstream side in the insertion direction of the blade holder 33 into the housing portion 36. Shorter as you follow.

  According to these configurations, when the blade holder 33 is inserted into the housing portion 36 of the support portion 34 and further inserted further, the axis of the photosensitive drum 21 in the housing portion 36 of the blade holder 33 automatically. A position with respect to the direction is determined. Thereby, the positioning of the blade holder 33 can be easily realized.

  Further, the cleaning device 30 having the above configuration is mounted on the image forming apparatus 1.

  According to this configuration, it is possible to provide the image forming apparatus 1 that can reduce the wear of the blade member 32 and the photosensitive drum 21 and can suppress the occurrence of poor cleaning.

  Further, the image forming apparatus 1 equipped with the cleaning device 30 rotates the photosensitive drum 21 in the opposite direction to that during image formation before image formation.

  According to this configuration, the blade holder 33 that comes into contact with the surface of the photosensitive drum 21 via the blade member 32 can be displaced in a direction in which the blade holder 33 is pulled out from the housing portion 36. Thereby, it is possible to appropriately reset the position of the blade holder 33 in the direction of displacement with the movement of the blade member 32 (depth direction with respect to the opening 36a of the accommodating portion 36).

  Further, in the image forming apparatus 1 equipped with the cleaning device 30, the length in the depth direction with respect to the opening 36 a of the housing portion 36 is the surface of the photosensitive drum 21 when the photosensitive drum 21 rotates in the direction opposite to that at the time of image formation. Longer than the distance traveled.

  According to this configuration, it is possible to prevent the blade holder 33 from falling out of the accommodating portion 36 when the photosensitive drum 21 is rotated in the direction opposite to that at the time of image formation.

  In addition, the image forming apparatus 1 includes a detection unit 61 that detects a coverage (toner occupancy with respect to the paper surface) in image formation, and after performing image formation on a document whose coverage is lower than a predetermined value, the coverage is higher than the predetermined value. Before the image formation is performed on the original, the photosensitive drum 21 is rotated in the direction opposite to that at the time of image formation.

  If the coverage is relatively low, the friction coefficient of the surface of the photosensitive drum 21 is increased and the frictional force between the blade member 32 and the photosensitive drum 21 is increased, so that the blade holder 33 is opened in the opening 36 a of the housing portion 36. Is displaced toward the back side. Therefore, according to the above configuration, the position of the blade holder 33 is appropriately reset after image formation is performed on a document whose coverage is lower than a predetermined value and before image formation is performed on a document whose coverage is higher than a predetermined value. Is possible.

  Further, the image forming apparatus 1 starts from a document whose coverage is lower than a predetermined value (for example, 2%) in a same image forming job, that is, while a plurality of images are continuously formed. When the original is higher than 5%), the image formation is temporarily stopped and the photosensitive drum 21 is rotated in the direction opposite to that at the time of image formation.

  According to this configuration, it is possible to appropriately reset the position of the blade holder 33 even while a plurality of images are continuously formed in the same image forming job.

  The image forming apparatus 1 is an image forming apparatus that can sequentially form images of a plurality of colors, and the coverage of the color (yellow (Y)) of the upstream image is a predetermined value (for example, 20%). If it becomes higher than that, the photosensitive drum 21 is rotated in the direction opposite to that at the time of image formation.

  According to this configuration, the blade holder can cope with the fluctuation of the frictional force between the blade member 32 and the photosensitive drum 21 that may occur in the image forming apparatus capable of sequentially superposing and forming images of a plurality of colors. It is possible to reset the position 33 properly.

  Although the embodiments of the present invention have been described above, the scope of the present invention is not limited to these embodiments, and various modifications can be made without departing from the spirit of the invention.

  For example, in the above-described embodiment, the image forming apparatus 1 including the cleaning device 30 is a so-called tandem color printing image forming apparatus in which images of a plurality of colors are sequentially stacked using the intermediate transfer belt 11. The present invention is not limited to such a model, and may be an image forming apparatus for color printing or an image forming apparatus for monochrome printing that is not a tandem type.

  The present invention can be used in a cleaning apparatus and an image forming apparatus.

DESCRIPTION OF SYMBOLS 1 Image forming apparatus 11 Intermediate transfer belt 20 Image forming part 21 Photosensitive drum (image carrier)
30 Cleaning Device 32 Blade Member 33 Blade Holder 33a Blade Holder (Holder)
33b Supported part 34 Support part 35 Discharge screw 36 Housing part 36a, 36e Opening 36b First surface 36c Second surface 36d Inclined part 37 Engaging part 37a Convex part 37b Concave part 60 Control part 61 Detection part

Claims (18)

A blade member that comes into contact with the surface of the image carrier and removes deposits on the surface;
A blade holder that has flexibility and holds the blade member by a holding portion provided on one end side;
A support part for supporting a supported part provided on the opposite end side of the holding part of the blade holder;
The supported portion of the blade holder is received from an opening provided in the support portion and facing the image carrier, and the blade member is moved along the moving direction of the surface of the image carrier. An accommodating portion that supports the blade holder so that the portion can be displaced,
The accommodating portion includes an inclined portion configured with a curved surface extending in a direction away from the surface of the image carrier as it goes toward the back with respect to the opening;
The cleaning device according to claim 1, wherein the blade holder is not fixed to the housing portion. The cleaning device according to claim 1 , wherein the blade holder includes a cylindrical surface at a tip of the supported portion. The accommodating part cleaning apparatus according to claim 1 or claim 2, characterized in that extending parallel to the direction of the opening intersects the movement direction of the surface of the image bearing member. A blade member that comes into contact with the surface of the image carrier and removes deposits on the surface;
A blade holder that has flexibility and holds the blade member by a holding portion provided on one end side;
A support part for supporting a supported part provided on the opposite end side of the holding part of the blade holder;
The supported portion of the blade holder is received from an opening provided in the support portion and facing the image carrier, and the blade member is moved along the moving direction of the surface of the image carrier. An accommodating portion for supporting the blade holder so that the portion can be displaced;
With
The receiving portion is a length corresponding to the displacement direction of the blade holder is, rather long, towards the middle than at both ends in the direction intersecting the moving direction of the surface of the image bearing member,
The cleaning device, wherein the blade holder is not fixed to the housing portion . The cleaning device according to claim 4 , wherein the housing portion includes an inclined portion that extends in a direction away from the surface of the image carrier as it goes toward the back with respect to the opening. The cleaning device according to claim 5 , wherein the inclined portion is constituted by a surface. Apparatus according to any one of claims 4 to claim 6 wherein the blade holder is characterized in that it comprises a cylindrical surface on the distal end of the supported portion. The cleaning device according to any one of claims 4 to 7 , wherein the housing portion extends in parallel with a direction in which the opening intersects the moving direction of the surface of the image carrier. The blade holder and the housing portion include an engaging portion that engages with each other inside the housing portion to prevent displacement of the blade holder in a direction that intersects the moving direction of the surface of the image carrier. The cleaning device according to any one of claims 1 to 8 , wherein the cleaning device is characterized in that: The cleaning device according to claim 9 , wherein the engaging portion includes a convex portion and a concave portion that engage with each other. The length of the concave portion in the direction intersecting the moving direction of the surface of the image carrier is shortened from the downstream side to the upstream side in the insertion direction of the blade holder into the accommodating portion. 10. A cleaning device according to 10 . The length of the blade holder or the container in the direction intersecting the moving direction of the surface of the image carrier is shortened from the upstream side to the downstream side in the insertion direction of the blade holder into the container. The cleaning device according to claim 9 . Image forming apparatus characterized by mounting the apparatus according to any one of claims 1 to 12. The image forming apparatus according to claim 13 , wherein the image carrier is rotated in a direction opposite to that at the time of image formation before the image formation. Length in the depth direction with respect to the opening of the receiving portion, in claim 14, wherein longer than the moving distance of the surface of the image bearing member in the case of rotating the image bearing member in a direction opposite to that during the image formation The image forming apparatus described. A detection unit for detecting the toner occupancy ratio on the paper surface;
After image formation is performed on a document having a toner occupancy ratio lower than a predetermined value, and before image formation is performed on a document having a toner occupancy ratio higher than a predetermined value, the image carrier is rotated in the opposite direction to that during image formation. the image forming apparatus according to claim 14 or claim 15, characterized in that. A detection unit for detecting the toner occupancy ratio on the paper surface;
When switching from a document having a toner occupancy ratio lower than a predetermined value to a document having a higher toner value within the same image forming job, image formation is temporarily stopped and the image carrier is rotated in the opposite direction to that during image formation. the image forming apparatus according to any one of claims 14 to claim 16, characterized in that. An image forming apparatus capable of sequentially superimposing a plurality of color images, comprising a detection unit for detecting a toner occupancy ratio with respect to a paper surface,
When the color toner occupancy of the upstream side of the image becomes higher than a predetermined value, any one of claims 14 to claim 17, the time of image formation of the image bearing member, characterized in that counter-rotating The image forming apparatus described in 1.