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WO2023282936A1 - Image forming apparatus with flexible sheet member - Google Patents

Image forming apparatus with flexible sheet member Download PDF

Info

Publication number
WO2023282936A1
WO2023282936A1 PCT/US2022/012730 US2022012730W WO2023282936A1 WO 2023282936 A1 WO2023282936 A1 WO 2023282936A1 US 2022012730 W US2022012730 W US 2022012730W WO 2023282936 A1 WO2023282936 A1 WO 2023282936A1
Authority
WO
WIPO (PCT)
Prior art keywords
sheet member
flexible sheet
frame
elongate portion
roller
Prior art date
Application number
PCT/US2022/012730
Other languages
French (fr)
Inventor
Kensuke Nakajima
Satoru Hori
Koji Miyake
Shun Ikeura
Original Assignee
Hewlett-Packard Development Company, L.P.
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by Hewlett-Packard Development Company, L.P. filed Critical Hewlett-Packard Development Company, L.P.
Publication of WO2023282936A1 publication Critical patent/WO2023282936A1/en

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Classifications

    • G—PHYSICS
    • G03—PHOTOGRAPHY; CINEMATOGRAPHY; ANALOGOUS TECHNIQUES USING WAVES OTHER THAN OPTICAL WAVES; ELECTROGRAPHY; HOLOGRAPHY
    • G03G—ELECTROGRAPHY; ELECTROPHOTOGRAPHY; MAGNETOGRAPHY
    • G03G15/00—Apparatus for electrographic processes using a charge pattern
    • G03G15/06—Apparatus for electrographic processes using a charge pattern for developing
    • G03G15/08—Apparatus for electrographic processes using a charge pattern for developing using a solid developer, e.g. powder developer
    • G03G15/0806—Apparatus for electrographic processes using a charge pattern for developing using a solid developer, e.g. powder developer on a donor element, e.g. belt, roller
    • G03G15/0812—Apparatus for electrographic processes using a charge pattern for developing using a solid developer, e.g. powder developer on a donor element, e.g. belt, roller characterised by the developer regulating means, e.g. structure of doctor blade
    • G—PHYSICS
    • G03—PHOTOGRAPHY; CINEMATOGRAPHY; ANALOGOUS TECHNIQUES USING WAVES OTHER THAN OPTICAL WAVES; ELECTROGRAPHY; HOLOGRAPHY
    • G03G—ELECTROGRAPHY; ELECTROPHOTOGRAPHY; MAGNETOGRAPHY
    • G03G21/00—Arrangements not provided for by groups G03G13/00 - G03G19/00, e.g. cleaning, elimination of residual charge
    • G03G21/0005—Arrangements not provided for by groups G03G13/00 - G03G19/00, e.g. cleaning, elimination of residual charge for removing solid developer or debris from the electrographic recording medium
    • G03G21/0011—Arrangements not provided for by groups G03G13/00 - G03G19/00, e.g. cleaning, elimination of residual charge for removing solid developer or debris from the electrographic recording medium using a blade; Details of cleaning blades, e.g. blade shape, layer forming
    • G—PHYSICS
    • G03—PHOTOGRAPHY; CINEMATOGRAPHY; ANALOGOUS TECHNIQUES USING WAVES OTHER THAN OPTICAL WAVES; ELECTROGRAPHY; HOLOGRAPHY
    • G03G—ELECTROGRAPHY; ELECTROPHOTOGRAPHY; MAGNETOGRAPHY
    • G03G15/00—Apparatus for electrographic processes using a charge pattern
    • G03G15/14—Apparatus for electrographic processes using a charge pattern for transferring a pattern to a second base
    • G03G15/16—Apparatus for electrographic processes using a charge pattern for transferring a pattern to a second base of a toner pattern, e.g. a powder pattern, e.g. magnetic transfer
    • G03G15/1605—Apparatus for electrographic processes using a charge pattern for transferring a pattern to a second base of a toner pattern, e.g. a powder pattern, e.g. magnetic transfer using at least one intermediate support
    • G03G15/161—Apparatus for electrographic processes using a charge pattern for transferring a pattern to a second base of a toner pattern, e.g. a powder pattern, e.g. magnetic transfer using at least one intermediate support with means for handling the intermediate support, e.g. heating, cleaning, coating with a transfer agent

Definitions

  • An image forming apparatus may include a transfer belt to convey a toner image to transfer the toner image onto a print medium, and a cleaning device to remove residual toner particles that remain on the transfer belt without having been transferred onto the print medium.
  • FIG. 1 is a schematic view of an example image forming apparatus.
  • FIG. 2 is an exploded view of an example cleaning device.
  • FIG. 3 is a side view illustrating a part of the example cleaning device.
  • FIG. 4 is a cross-sectional view of the example cleaning device of FIG. 3, taken along line IV-IV.
  • FIG. 5 is a perspective view illustrating a part of a support of the example cleaning device.
  • FIG. 6 is a perspective view illustrating an operational state during an example assembly procedure of the cleaning device.
  • FIG. 7 is a perspective view illustrating another operational state of the example assembly procedure of the cleaning device.
  • FIG. 8 is a perspective view illustrating another operational state of the example assembly procedure of the cleaning device.
  • FIG. 9 is a perspective view illustrating another operational state of the example of the assembly procedure of the cleaning device.
  • FIG. 10 is a cross-sectional view of the example cleaning device, illustrating a movement of toner particles to be recovered by the cleaning device.
  • FIG. 11 is a cross-sectional view illustrating another example cleaning device.
  • FIG. 12 is a cross-sectional view illustrating another example cleaning device.
  • an example image forming apparatus or device such as a printer, for example, may include a support structure in which a flexible sheet member is biased against a support by the restoring force of the flexible sheet member in order to support the flexible sheet member.
  • the image forming apparatus includes a transfer belt on which toner particles are conveyed, and a cleaning device that removes the toner particles from the transfer belt.
  • the cleaning device may include the support structure including the flexible sheet member that is positioned adjacent the transfer belt, to collect the toner particles, as will be described further below.
  • the example image forming apparatus 1 may use colors such as cyan, magenta, yellow, and black to form a color image.
  • the image forming apparatus 1 includes a conveying device 10 to convey a sheet 5 which is a print medium, a plurality of developing devices 20C, 20M, 20Y, and 20K (of which a single one may be referred to herein as a "developing device 20") to develop electrostatic latent images into respective toner images of the four colors, a plurality of photoconductors 40C, 40M, 40Y, and 40K (of which a single one may be referred to herein as a "photoconductor 40") having respective surfaces to form the electrostatic latent images, a transfer device 30 to layer the toner images of the four colors into a single toner image and to transfer the toner image onto the sheet 5, a fixing device 50 to fix the toner image to the sheet 5, and a discharge device 60
  • the conveying device 10 conveys the sheet 5, which may be a paper sheet for example, on which an image is to be formed, along a conveyance path 12.
  • the sheets 5 are initially stacked and contained in a cassette 7, to be picked up and conveyed by a sheet feeding roller 11 of the conveying device 10.
  • the conveying device 10 directs the sheet 5 along the conveyance path 12, to reach a transfer region 13 at a same timing as the toner image so as to transfer the toner image from the transfer device 30 to the sheet 5 at the transfer region 13.
  • the developing devices 20C, 20M, 20Y, and 20K are provided for the respective colors of cyan toner, magenta toner, yellow toner and black toner.
  • Each one of the developing devices 20C, 20M, 20Y, and 20K includes a developing roller 110 to carry a toner to the adjacent photoconductor 40.
  • the developing device 20 uses a two-component developer containing a toner and a carrier as the developer. Namely, in the developing device 20, the mixing ratio of the toner and the carrier is adjusted to a desired mixing ratio, and the toner and the carrier are further mixed and stirred to uniformly disperse the toner, so that the developer is adjusted to have an optimal charge amount.
  • the developer is carried by the developing roller 110.
  • the developing roller 110 rotates to convey the developer to a developing region facing the photoconductor 40, where the toner contained in the developer carried by the developing roller 110 is transferred to the electrostatic latent image formed on a peripheral surface of the photoconductor 40, to develop the electrostatic latent image.
  • the transfer device 30 conveys the toner images formed by the respective developing devices 20C, 20M, 20Y, and 20K to be transferred onto the sheet 5.
  • the transfer device 30 includes a transfer belt 31 (e.g., an endless belt) onto which the toner images of the respective colors are primarily transferred from the respective photoconductors 40C, 40M, 40Y, and 40K, in a layered manner, so as to form a single composite toner image.
  • the transfer belt 31 conveys the composite toner image to the transfer region 13 to be secondarily transferred onto the sheet 5.
  • the transfer device 30 additionally includes a tension roller 34 to tension the transfer belt 31 , idler rollers 35 and 36, a drive roller 37 to drive the transfer belt 31 , primary transfer rollers 32C, 32M, 32Y, and 32Kto nip the transfer belt 31 with the photoconductors 40C, 40M, 40Y, and 40K, respectively, and a secondary transfer roller 33 to nip the transfer belt 31 with the drive roller 37 at the transfer region 13.
  • the photoconductors 40C, 40M, 40Y, and 40K may also be referred to as electrostatic latent image carriers, photoconductor drums, or the like.
  • the four photoconductors 40C, 40M, 40Y, and 40K are provided for the respective four colors, and are provided along a moving direction of the transfer belt 31 .
  • the developing device 20, a charging device 41 , an exposure unit 42, and the cleaning device 43 are provided adjacent each photoconductor 40.
  • the charging device 41 may contact the photoconductor 40 to charge the surface of the photoconductor 40 to a predetermined potential.
  • the exposure unit 42 exposes the surface of the photoconductor 40 to a light according to an image to be formed on the sheet 5. Accordingly, a portion of the surface of the photoconductor 40, which is exposed to the light of the exposure unit 42, changes in potential to form the electrostatic latent image.
  • the developing devices 20C, 20M, 20Y, and 20K develop the electrostatic latent images, which are formed on the respective photoconductors 40C, 40M, 40Y, and 40K, with toner supplied from respective toner tanks 18C, 18M, 18Y, and 18K, which are positioned adjacent the respective developing devices 20C, 20M, 20Y, and 20K, so as to generate the toner images of the respective colors of toner.
  • the toner tanks 18C, 18M, 18Y, and 18K are filled with cyan, magenta, yellow, and black toners, respectively.
  • the cleaning device 43 recovers the toner that remains on the corresponding photoconductor 40 after the toner image formed on the photoconductor 40 is primarily transferred onto the transfer belt 31.
  • the sheet 5 is conveyed through a fixing nip region of the fixing device 50, where the sheet 5 is heated and pressed to cause the toner image to adhere to the sheet 5, so as to fix the toner image.
  • the fixing device 50 includes a heating roller 52 to heat the sheet 5, and a pressure roller 54 to press against and rotationally drive the heating roller 52.
  • the heating roller 52 and the pressure roller 54 are each formed in a cylindrical shape, and the heating roller 52 includes a heat source therein, such as a halogen lamp.
  • a contact region between the heating roller 52 and the pressure roller 54 forms the fixing nip region.
  • the discharge device 60 includes discharge rollers 62 and 64 to discharge the sheet 5 with the fixed toner image to the outside of the image forming apparatus 1 .
  • the image forming apparatus 1 further includes a controller 80.
  • the controller 80 may be a computer including a processor, a storage unit, an input device, a display device, and the like, to control the operation of the image forming apparatus 1.
  • the storage unit of the controller 80 may store a control program that is to be executed by the processor to control various processes that operate the image forming apparatus 1 .
  • the cleaning device 70 is provided downstream of the transfer region 13 in a conveyance direction (or rotational direction) C of the transfer belt 31.
  • the cleaning device 70 removes residual (or non-transferred) toner particles that remain on the transfer belt 31 after the toner image has been transferred onto the sheet 5, at the transfer region 13.
  • the example cleaning device 70 includes a rotatable device 71 , a flexible sheet member (also referred to herein as an elastic plate-shaped member) 72, and a support 73.
  • the rotatable device 71 rotates about a rotational axis AX that extends in a longitudinal direction (also referred to herein as a lateral direction or an M X-direction").
  • the rotatable device 71 includes a roller 81 and a rotatable shaft 82.
  • the roller 81 is a rigid roller made of a rigid material such as metal and having a substantially cylindrical shape.
  • the roller 81 is located adjacent the flexible sheet member 72, so that an outer peripheral surface 81a of the roller 81 is in contact with or positioned in proximity to the flexible sheet member 72.
  • the outer peripheral surface 81a forms a surface of the rotatable device 71 to be scraped by the flexible sheet member 72. As illustrated in FIG. 4, the outer peripheral surface 81a of the roller 81 contacts a surface of the transfer belt 31 .
  • the roller 81 is disposed downstream of the transfer region 13 in the conveyance direction C of the transfer belt 31 , and receives power from an electric motor to rotate about the rotational axis AX in a state where the roller 81 contacts the surface of the transfer belt 31 at a point of contact.
  • the roller 81 rotates in a direction opposite the conveyance direction C of the transfer belt 31 at the point of contact.
  • the rotational direction of the roller 81 may be the same as the conveyance direction C of the transfer belt 31 at the point of contact.
  • the roller 81 receives an electric bias during an image formation operation, to draw the residual toner particles by electrostatic force, onto the outer peripheral surface 81a of the roller, in which the residual toner particles correspond to non-transferred toner particles that remain on the transfer belt 31 after the toner image has been transferred onto the sheet 5 at the transfer region 13.
  • the rotatable shaft 82 of the rotatable device 71 is coupled with opposite longitudinal ends of the roller 81 , to protrude outwardly from the opposite ends of the roller 81 , along the rotational axis AX.
  • the rotatable shaft 82 of the rotatable device 71 is rotatably supported by a pair of brackets 92.
  • the flexible sheet member 72 is, for example, a scraper made of an elastic or flexible material such as metal or resin, to scrape off toner particles adhered to the outer peripheral surface 81a of the roller 81 .
  • the flexible sheet member 72 may be a thin sheet made of stainless steel, having a thickness of 0.06 mm to 0.1 mm.
  • the flexible sheet member 72 has two opposite surfaces 72a and 72b. As illustrated in FIG. 2, the flexible sheet member 72 may include a main body 74 and a tongue 75. The main body 74 and the tongue 75 are integrally formed.
  • the main body 74 has a substantially rectangular planar shape so that a width of the main body 74 in the lateral direction is greater than a height of the main body 74 in the transverse or height direction.
  • the main body 74 includes a contact edge portion 84, a rear edge portion 85, and a pair of side edge portions 86.
  • the contact edge portion 84 extends in the lateral direction (X- direction) parallel to the rotational axis AX.
  • the contact edge portion 84 contacts the outer peripheral surface 81a of the roller 81 , to scrape off the toner particles adhered to the outer peripheral surface 81a of the rotating roller 81 , so as to separate the toner particles from the roller 81 .
  • the rear edge portion 85 is disposed opposite the contact edge portion 84, and extends substantially parallel to the contact edge portion 84.
  • the pair of side edge portions 86 extend between the contact edge portion 84 and the rear edge portion 85 in a transverse direction (also referred to herein as a height direction or a "Z-direction") that is perpendicular (orthogonal) to the lateral direction of the main body 74.
  • the tongue 75 protrudes outward in the lateral direction, from the side edge portion 86 at each end of the main body 74. As illustrated in FIG. 3, the tongue 75 includes a first edge portion 87 and a second edge portion 88. The first edge portion 87 extends continuously from the contact edge portion 84 of the main body 74 in the lateral direction, and is disposed adjacent the rotatable shaft 82 of the rotatable device 71 . The second edge portion 88 is formed at a position between the contact edge portion 84 and the rear edge portion 85 in the transverse direction of the flexible sheet member 72, and is disposed to contact or is positioned in proximity to a first elongate portion 91a of a frame 91 that is described further below. Namely, the tongue 75 is fitted between the rotatable device 71 and the frame 91 , in order to fixedly position the flexible sheet member 72 relative to the rotatable device 71 .
  • the support 73 uses the restoring force of the flexible sheet member 72 generated by an elastic deformation, to support the flexible sheet member 72.
  • the support 73 includes the frame 91 that extends in the lateral direction (X-direction) adjacent the rotatable device 71 , and the pair of brackets 92 to rotatably support the roller 81.
  • the frame 91 includes the first elongate portion 91a, a second elongate portion 91b, and a third elongate portion 91c.
  • the first elongate portion 91a, the second elongate portion 91 b, and the third elongate portion 91c extend in the lateral direction (X-direction), and are arranged in the transverse or height direction (Z-direction) of the frame 91 .
  • the first elongate portion 91a is disposed between the rotatable device 71 and the second elongate portion 91 b
  • the second elongate portion 91 b is disposed between the first elongate portion 91a and the third elongate portion 91c.
  • the first elongate portion 91a overlaps the third elongate portion 91c
  • the first elongate portion 91 a is offset from the second elongate portion 91 b so as to have no overlap with the second elongate portion 91 b
  • the second elongate portion 91 b at least partially overlaps the third elongate portion 91c.
  • the frame 91 connects the first elongate portion 91a, the second elongate portion 91 b, and the third elongate portion 91 c at opposite longitudinal ends of the frame 91 .
  • Each of the first elongate portion 91a, the second elongate portion 91b, and the third elongate portion 91c may have any suitable cross-sectional shape such as a rectangle, a polygon, or a circle.
  • the frame 91 forms a first slit 93 and a second slit 94 that extend in the X-direction.
  • the first slit 93 is formed between the first elongate portion 91a and the second elongate portion 91 b of the frame 91 .
  • the second slit 94 is formed between the second elongate portion 91b and the third elongate portion 91c of the frame 91 .
  • the first slit 93 and the second slit 94 are openings through which the flexible sheet member 72 is passable, and extend parallel to each other. When viewed in the Z-direction, the first slit 93 and the second slit 94 may be formed at positions to overlap each other.
  • the length of the first slit 93 and the second slit 94 in the X-direction may be set longer than the length of the roller 81 in the X-direction.
  • Each of the first slit 93 and the second slit 94 may have any suitable shape in which the dimension (e.g., width) in the X-direction is greater than the dimension (e.g., height) in the Z-direction.
  • the flexible sheet member 72 extends through the first slit and through the second slit substantially in the Z-direction, and is held in a bent state by the frame 91 .
  • the flexible sheet member 72 When the flexible sheet member 72 is inserted into the first slit 93 and into the second slit 94 in a bent state, the flexible sheet member 72 is biased against the frame 91 and the flexible sheet member 72 is held by the support 73 by the restoring force of the flexible sheet member 72.
  • the first elongate portion 91a may include a first plate 91 a1 and a second plate 91 a2.
  • the first plate 91 a1 extends on an X- Y plane. Namely, the first plate 91 a1 extends in the longitudinal direction (X- direction) of the frame 91 and in a depth direction (also referred to herein as a "Y- direction") of the frame 91 orthogonal to the longitudinal direction and the height direction (Z-direction) of the frame 91 .
  • the second plate 91 a2 extends from the first plate 91 a1 toward the flexible sheet member 72 so as to form an angle with the first plate 91 a1 .
  • the second plate 91 a2 is disposed to be tilted relative to the first plate 91 a1 , and the first elongate portion 91a has a substantially V- shape that is open to a flexible sheet member 72 side when viewed in the X- direction.
  • the pair of brackets 92 are coupled with opposite ends of the frame 91 in the X-direction.
  • the frame 91 and the pair of brackets 92 may be integrally formed by pressing a sheet metal.
  • the pair of brackets 92 extend from the longitudinal ends of the frame 91 in the Z-direction, and face each other in the X- direction.
  • the pair of brackets 92 form respective through-holes 92h that extend in the X-direction so as to rotatably support the rotatable shaft 82 of the rotatable device 71 , which are inserted into the through-holes 92h.
  • the pair of brackets 92 position the frame 91 to bias the flexible sheet member 72 against the outer peripheral surface 81 a of the roller 81.
  • the example cleaning device 70 may further include a seal 96 and a recovery container 98.
  • the seal 96 is provided on the second plate 91 a2 to extend from the first elongate portion 91 a to the roller 81 .
  • the seal 96 is made of, for example, an elastic or flexible material, and is disposed in close contact with the first surface 72a of the flexible sheet member 72.
  • the seal 96 guides the residual toner particles (or non-transferred toner particles), which are scraped off from the roller 81 by the flexible sheet member 72, to the recovery container 98.
  • the recovery container 98 is open upward, and may be below the first elongate portion 91a to recover the residual toner particles that are scraped off from the roller 81 by the flexible sheet member 72 and are guided by the seal 96.
  • the residual toner particles recovered by the recovery container 98 may be conveyed to a toner cartridge as a waste toner or a recycled toner via a conveyor device, for example, provided inside a housing of the image forming apparatus 1 .
  • FIGS. 6 to 9 illustrate an example assembly procedure to assemble the cleaning device 70. With reference to FIGS.
  • the flexible sheet member 72 when the flexible sheet member 72 is mounted to the support 73, the flexible sheet member 72 is inserted into the first slit 93 and into the second slit 94, so as to be fixed to the support 73.
  • the position of the rear edge portion 85 of the flexible sheet member 72 is adjusted such that the contact edge portion 84 of the flexible sheet member 72 contacts the outer peripheral surface 81a of the roller 81 .
  • the flexible sheet member 72 is inserted into the first slit 93 and into the second slit 94 such that the first surface 72a of the flexible sheet member 72 contacts the first elongate portion 91a and the third elongate portion 91c, and so that the second surface 72b of the flexible sheet member 72 contacts the second elongate portion 91b. Since the first slit 93 and the second slit 94 are formed at positions to overlap each other when viewed in the Z-direction, the flexible sheet member 72 is bent in a thickness direction of flexible sheet member 72.
  • the first elongate portion 91a, the second elongate portion 91b, and the third elongate portion 91c apply a bending force to the flexible sheet member 72 inserted into the first slit 93 and into the second slit 94, such that the flexible sheet member 72 is curved in a substantially S-shape.
  • the first elongate portion 91a and the third elongate portion 91c press the flexible sheet member 72 against the second elongate portion 91 b and the outer peripheral surface 81a of the roller 81 to form the S- shape.
  • a restoring force is generated in the bent flexible sheet member 72, and the flexible sheet member 72 is biased against the first elongate portion 91a, the second elongate portion 91 b, and the third elongate portion 91c by the restoring force. Accordingly, the flexible sheet member 72 is supported by the support 73 via the biasing force.
  • a bearing 95 is inserted onto the rotatable shaft 82 of the rotatable device 71 , and the bearing 95 is disposed between the rotatable shaft 82 and the bracket 92. Accordingly, the rotatable device 71 is rotatably supported by the pair of brackets 92.
  • the rotatable device 71 may receive power from an electric motor to rotate about the rotational axis AX, so that toner particles adhere to the outer peripheral surface 81a of the roller 81 and are scraped off by the flexible sheet member 72.
  • a frictional force generated between the rotating roller 81 and the flexible sheet member 72 may apply a force on the flexible sheet member 72 directed away from to the roller 81 .
  • first elongate portion 91a, the second elongate portion 91b, and the third elongate portion 91c have respective contact surfaces to frictionally engage with the flexible sheet member 72 when the flexible sheet member 72 contacts the outer peripheral surface 81a of the roller 81 , the support 73 restricts the retraction of the flexible sheet member 72.
  • the tongue 75 of the flexible sheet member 72 is fitted between the rotatable device 71 and the frame 91 , when a force is applied to retract the flexible sheet member 72, the second edge portion 88 of the tongue 75 abuts the first plate 91 a1 of the first elongate portion 91a to prevent the retraction of the flexible sheet member 72 relative to the roller 81 .
  • the tongue 75 is a stopper that prevents the retraction of the flexible sheet member 72, to fixedly position the main body 74 of the flexible sheet member 72 relative to the outer peripheral surface 81 a of the roller 81 .
  • the toner images primarily transferred from the photoconductors 40C, 40M, 40Y, and 40K onto the surface of the transfer belt 31 are conveyed in the conveyance direction C by the transfer belt 31 , and are secondarily transferred from the transfer belt 31 onto the sheet 5 at the transfer region 13 (of. FIG. 1 ). Toner particles that remain on the surface of the transfer belt 31 without having being transferred from the transfer belt 31 onto the sheet 5, are conveyed downstream the transfer region 13 toward the cleaning device 70.
  • the toner particles on the transfer belt 31 move to a region facing the roller 81 , as illustrated in FIG. 10, the toner particles are recovered by the roller 81 by an electrostatic force.
  • the toner particles adhered to the outer peripheral surface 81a of the roller 81 are rotated toward the flexible sheet member 72 by the rotation of the roller 81 , and are scraped off by the flexible sheet member 72 to be separated from the roller 81 .
  • the toner particles separated from the roller 81 fall while sliding along the seal 96, and are recovered by the recovery container 98.
  • the residual toner particles recovered by the recovery container 98 are conveyed into the toner cartridge as a waste toner or a recycled toner, for example, by a conveyor device.
  • the flexible sheet member 72 extends through the first slit and through the second slit in a state where the flexible sheet member 72 is bent in the thickness direction, the flexible sheet member 72 is biased against the frame 91 by the restoring force of the flexible sheet member 72. Accordingly, when the flexible sheet member 72 contacts the outer peripheral surface 81a of the roller 81 , a frictional force can be generated between the flexible sheet member 72 and the frame 91 to fix the flexible sheet member 72 to the support 73.
  • the flexible sheet member 72 is positioned to contact the outer peripheral surface 81a of the roller 81 with a suitable contact pressure.
  • the contact pressure of the flexible sheet member 72 against the outer peripheral surface 81 a of the roller 81 is too low, the toner particles adhered to the outer peripheral surface 81a may not be appropriately removed, and the cleaning performance of the cleaning device 70 is reduced.
  • the contact pressure of the flexible sheet member 72 against the outer peripheral surface 81a of the roller 81 is too great, the outer peripheral surface 81a of the roller 81 may be worn or damaged, and the lifespan of the roller 81 may be reduced. Therefore, the flexible sheet member 72 is set to apply a predetermined contact pressure against the outer peripheral surface 81a of the roller 81.
  • the contact pressure of the flexible sheet member 72 against the outer peripheral surface 81 a of the roller 81 depends on a distance Yref between a curvature fulcrum 72c that is a fulcrum of an elastic deformation of the flexible sheet member 72 and the contact edge portion 84 in the Y-direction, and a distance Zref between the curvature fulcrum 72c and the contact edge portion 84 in the Z-direction (of. FIG. 4).
  • the distance Yref and the distance Zref are set within a predetermined range.
  • the curvature fulcrum 72c is formed in a contact surface between the flexible sheet member 72 and the first elongate portion 91a. Namely, the first elongate portion 91 a is positioned to bias the flexible sheet member 72 against the outer peripheral surface 81a of the roller 81 at the predetermined contact pressure.
  • the flexible sheet member such as a scraper may be fixed to a base with a screw, an adhesive, or the like.
  • a fixing member such as a screw
  • a dimensional error of the screw or a screw hole may cause a mounting error of the flexible sheet member.
  • the thickness of the adhesive may be non-uniform. The mounting error and the non-uniformity of the thickness of the adhesive may cause variation in the distance Yref and the distance Zref.
  • the example flexible sheet member 72 of the cleaning device 70 is supported by the support 73 via a frictional force generated between the flexible sheet member 72 and the frame 91 without using a fixing member such as a screw. Therefore, in the cleaning device 70, the number of components can be reduced relative to a cleaning device in which a fixing device fixes the scraper to the base.
  • the cumulative tolerance during assembly can be reduced given a reduced number of components, so as to more easily set the distance Yref and the distance Zref within the predetermined range. Accordingly, the contact pressure of the contact edge portion 84 of the flexible sheet member 72 against the outer peripheral surface 81 a of the roller 81 can be set with greater accuracy, so as to inhibit a reduction in the lifespan of the roller 81 while achieving a suitable cleaning performance. Additionally, the cleaning device 70 can be more easily assembled given that the number of components is reduced.
  • a pressure difference may be generated between a fixed portion and a non-fixed portion of the scraper, and the contact edge portion of the scraper may be deformed in a wavy shape.
  • the waviness formed in the contact edge portion may cause the contact pressure of the contact edge portion against the surface of the roller to vary in the longitudinal direction of the roller.
  • the flexible sheet member 72 is held at a uniform pressure in the X-direction, so as to suppress the formation of waviness in the contact edge portion 84 of the flexible sheet member 72, and to suppress variations in the contact pressure in the X-direction.
  • the rear edge portion 85 of the flexible sheet member 72 is biased against the third elongate portion 91c, so as to prevent a vibration of the rear edge portion 85 from a frictional force between the roller 81 and the flexible sheet member 72, and thereby suppress a variation in the contact pressure of the flexible sheet member 72 that may be caused by the propagation of such vibration to the contact edge portion 84. Further, the generation of noise due to such vibration of the rear edge portion 85 is suppressed.
  • an example cleaning device 170 includes an intermediate roller (also referred to herein as an abutting roller) 180 in addition to the roller 81 that is positioned as a distal roller in the example of FIG.11 .
  • the roller (distal roller) 81 is a rigid roller having, for example, a substantially cylindrical shape, and receives power from the electric motor to rotate about the rotational axis AX in a state in which the roller (distal roller) 81 is spaced away from the transfer belt 31.
  • the intermediate roller 180 is disposed between the transfer belt 31 and the roller (distal roller) 81 .
  • the intermediate roller 180 is, for example, a conductive sponge roller having a substantially cylindrical shape, and receives power from an electric motor to rotate about an axis in a state where the intermediate roller 180 contacts the surface of the transfer belt 31 and the surface of the roller (distal roller) 81.
  • the intermediate roller 180 receives bias electric power to be charged during image formation.
  • the intermediate roller 180 recovers the residual toner particles from the transfer belt 31 via an electrostatic force, in which the residual toner particles corresponds to the toner particles remaining on the transfer belt 31 without having been transferred on to the sheet 5 at the transfer region 13.
  • the toner particles recovered by the intermediate roller 180 move to a region facing the roller (or distal roller) 81 , the toner particles adhere to the roller (distal roller) 81 via an electrostatic force.
  • a rotation of the roller (distal roller) 81 transfers the toner particles adhered thereto, to the region of the roller (distal roller) 81 facing (e.g., contacting) the flexible sheet member 72, where the adhered toner particles are scraped off from the roller (distal roller) 81 by the flexible sheet member 72.
  • the toner particles on the transfer belt 31 are leveled by the intermediate roller 180 made of a conductive sponge, so as to increase the recovery rate of the toner particles on the transfer belt 31.
  • the intermediate roller 180 may be a brush roller in some examples.
  • Another modification example of the cleaning device will be described. Hereinafter, differences with the cleaning device 70 described above will be mainly described, and a overlapping description may be omitted.
  • an example cleaning device 270 may not include the rotatable device 71 nor the pair of brackets 92.
  • the flexible sheet member 72 of the cleaning device 270 is supported by the frame 91 by extending through the first slit 93 and through the second slit 94.
  • the flexible sheet member 72 directly contacts the surface of the transfer belt 31 to be biased against the surface of the transfer belt 31 with a predetermined contact pressure.
  • the drive roller 37 that extends in the X-direction, rotates to cause the transfer belt 31 to rotate in the conveyance direction C.
  • the residual toner particles adhered to the transfer belt 31 are carried to the region facing the flexible sheet member 72 by the rotation of the transfer belt 31, where the flexible sheet member 72 scrapes off the residual toner particles from the transfer belt 31.
  • the support 73 may support a flexible sheet member other than a scraper.
  • the support 73 may support a developing plate for a developing device 20 (cf. FIG. 1 ), as the flexible sheet member 72, in which the developing plate contacts or extends in proximity to the developing roller 110.
  • the developing plate may be made of an elastic material such as metal or resin, and may extend through the first slit 93 and through the second slit 94 to be biased against the frame 91 of the support 73, so as to be supported by the support 73.
  • the developing plate supported by the support 73 contacts a surface of the developing roller 110 of the developing device 20 at a constant contact pressure. Irregularities are formed on an outer peripheral surface of the developing roller 110 to impart a given roughness to the outer peripheral surface, so as to frictionally charge the developer, with the developing plate contacting the outer peripheral surface.
  • the developing plate limits the thickness of the toner carried on the developing roller 110 to a predetermined thickness, and uniformly charges the toner by friction.
  • the developing plate supported by the support 73 contacts the outer peripheral surface of the developing roller 110 at a suitable contact pressure, to as to form a layer of the developer having a predetermined thickness, on the developing roller 110.
  • the developing plate may be disposed in proximity to the surface of the developing roller 110 with a predetermined gap formed therebetween, instead of contacting the surface of the developing roller 110.
  • the developing plate limits the thickness of the toner carried on the developing roller 110 to the predetermined thickness.

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  • Physics & Mathematics (AREA)
  • General Physics & Mathematics (AREA)
  • Cleaning In Electrography (AREA)
  • Electrostatic Charge, Transfer And Separation In Electrography (AREA)

Abstract

An example image forming apparatus includes: a rotatable device to rotate about a rotational axis that extends in a longitudinal direction, a flexible sheet member located adjacent a surface of the rotatable device, and a support including a frame that extends in the longitudinal direction adjacent the rotatable device. The frame forms a first slit and a second slit that extend in the longitudinal direction, and the flexible sheet member extends through the first slit and through the second slit to bias the flexible sheet member against the frame.

Description

IMAGE FORMING APPARATUS WITH FLEXIBLE SHEET MEMBER
BACKGROUND
[0001] An image forming apparatus may include a transfer belt to convey a toner image to transfer the toner image onto a print medium, and a cleaning device to remove residual toner particles that remain on the transfer belt without having been transferred onto the print medium.
BRIEF DESCRIPTION OF DRAWINGS
[0002] FIG. 1 is a schematic view of an example image forming apparatus. [0003] FIG. 2 is an exploded view of an example cleaning device.
[0004] FIG. 3 is a side view illustrating a part of the example cleaning device.
[0005] FIG. 4 is a cross-sectional view of the example cleaning device of FIG. 3, taken along line IV-IV.
[0006] FIG. 5 is a perspective view illustrating a part of a support of the example cleaning device.
[0007] FIG. 6 is a perspective view illustrating an operational state during an example assembly procedure of the cleaning device.
[0008] FIG. 7 is a perspective view illustrating another operational state of the example assembly procedure of the cleaning device.
[0009] FIG. 8 is a perspective view illustrating another operational state of the example assembly procedure of the cleaning device.
[0010] FIG. 9 is a perspective view illustrating another operational state of the example of the assembly procedure of the cleaning device.
[0011] FIG. 10 is a cross-sectional view of the example cleaning device, illustrating a movement of toner particles to be recovered by the cleaning device. [0012] FIG. 11 is a cross-sectional view illustrating another example cleaning device. [0013] FIG. 12 is a cross-sectional view illustrating another example cleaning device.
DETAILED DESCRIPTION
[0014] In the following description, with reference to the drawings, the same reference numbers are assigned to the same components or to similar components having the same function, and overlapping description is omitted. [0015] According to the present disclosure an example image forming apparatus or device such as a printer, for example, may include a support structure in which a flexible sheet member is biased against a support by the restoring force of the flexible sheet member in order to support the flexible sheet member. In some examples, the image forming apparatus includes a transfer belt on which toner particles are conveyed, and a cleaning device that removes the toner particles from the transfer belt. The cleaning device may include the support structure including the flexible sheet member that is positioned adjacent the transfer belt, to collect the toner particles, as will be described further below. [0016] An example image forming apparatus (or image forming device) 1 will be described with reference to FIG. 1 . The example image forming apparatus 1 may use colors such as cyan, magenta, yellow, and black to form a color image. The image forming apparatus 1 includes a conveying device 10 to convey a sheet 5 which is a print medium, a plurality of developing devices 20C, 20M, 20Y, and 20K (of which a single one may be referred to herein as a "developing device 20") to develop electrostatic latent images into respective toner images of the four colors, a plurality of photoconductors 40C, 40M, 40Y, and 40K (of which a single one may be referred to herein as a "photoconductor 40") having respective surfaces to form the electrostatic latent images, a transfer device 30 to layer the toner images of the four colors into a single toner image and to transfer the toner image onto the sheet 5, a fixing device 50 to fix the toner image to the sheet 5, and a discharge device 60 to discharge the sheet 5 from the image forming apparatus 1. Additionally, the image forming apparatus 1 includes an example cleaning device 70 to remove non-transferred toner particles (or residual toner particles) from the transfer device 30.
[0017] The conveying device 10 conveys the sheet 5, which may be a paper sheet for example, on which an image is to be formed, along a conveyance path 12. The sheets 5 are initially stacked and contained in a cassette 7, to be picked up and conveyed by a sheet feeding roller 11 of the conveying device 10. The conveying device 10 directs the sheet 5 along the conveyance path 12, to reach a transfer region 13 at a same timing as the toner image so as to transfer the toner image from the transfer device 30 to the sheet 5 at the transfer region 13.
[0018] The developing devices 20C, 20M, 20Y, and 20K are provided for the respective colors of cyan toner, magenta toner, yellow toner and black toner. Each one of the developing devices 20C, 20M, 20Y, and 20K includes a developing roller 110 to carry a toner to the adjacent photoconductor 40. The developing device 20 uses a two-component developer containing a toner and a carrier as the developer. Namely, in the developing device 20, the mixing ratio of the toner and the carrier is adjusted to a desired mixing ratio, and the toner and the carrier are further mixed and stirred to uniformly disperse the toner, so that the developer is adjusted to have an optimal charge amount. The developer is carried by the developing roller 110. The developing roller 110 rotates to convey the developer to a developing region facing the photoconductor 40, where the toner contained in the developer carried by the developing roller 110 is transferred to the electrostatic latent image formed on a peripheral surface of the photoconductor 40, to develop the electrostatic latent image.
[0019] The transfer device 30 conveys the toner images formed by the respective developing devices 20C, 20M, 20Y, and 20K to be transferred onto the sheet 5. The transfer device 30 includes a transfer belt 31 (e.g., an endless belt) onto which the toner images of the respective colors are primarily transferred from the respective photoconductors 40C, 40M, 40Y, and 40K, in a layered manner, so as to form a single composite toner image. The transfer belt 31 conveys the composite toner image to the transfer region 13 to be secondarily transferred onto the sheet 5. The transfer device 30 additionally includes a tension roller 34 to tension the transfer belt 31 , idler rollers 35 and 36, a drive roller 37 to drive the transfer belt 31 , primary transfer rollers 32C, 32M, 32Y, and 32Kto nip the transfer belt 31 with the photoconductors 40C, 40M, 40Y, and 40K, respectively, and a secondary transfer roller 33 to nip the transfer belt 31 with the drive roller 37 at the transfer region 13.
[0020] The photoconductors 40C, 40M, 40Y, and 40K may also be referred to as electrostatic latent image carriers, photoconductor drums, or the like. The four photoconductors 40C, 40M, 40Y, and 40K are provided for the respective four colors, and are provided along a moving direction of the transfer belt 31 . The developing device 20, a charging device 41 , an exposure unit 42, and the cleaning device 43 are provided adjacent each photoconductor 40.
[0021] The charging device 41 may contact the photoconductor 40 to charge the surface of the photoconductor 40 to a predetermined potential. The exposure unit 42 exposes the surface of the photoconductor 40 to a light according to an image to be formed on the sheet 5. Accordingly, a portion of the surface of the photoconductor 40, which is exposed to the light of the exposure unit 42, changes in potential to form the electrostatic latent image. The developing devices 20C, 20M, 20Y, and 20K develop the electrostatic latent images, which are formed on the respective photoconductors 40C, 40M, 40Y, and 40K, with toner supplied from respective toner tanks 18C, 18M, 18Y, and 18K, which are positioned adjacent the respective developing devices 20C, 20M, 20Y, and 20K, so as to generate the toner images of the respective colors of toner. The toner tanks 18C, 18M, 18Y, and 18K are filled with cyan, magenta, yellow, and black toners, respectively. The cleaning device 43 recovers the toner that remains on the corresponding photoconductor 40 after the toner image formed on the photoconductor 40 is primarily transferred onto the transfer belt 31.
[0022] After the toner image has been secondarily transferred onto the sheet 5, the sheet 5 is conveyed through a fixing nip region of the fixing device 50, where the sheet 5 is heated and pressed to cause the toner image to adhere to the sheet 5, so as to fix the toner image. The fixing device 50 includes a heating roller 52 to heat the sheet 5, and a pressure roller 54 to press against and rotationally drive the heating roller 52. The heating roller 52 and the pressure roller 54 are each formed in a cylindrical shape, and the heating roller 52 includes a heat source therein, such as a halogen lamp. A contact region between the heating roller 52 and the pressure roller 54 forms the fixing nip region. When the sheet 5 passes through the fixing nip region, the toner image is melted and fixed to the sheet 5.
[0023] The discharge device 60 includes discharge rollers 62 and 64 to discharge the sheet 5 with the fixed toner image to the outside of the image forming apparatus 1 .
[0024] The image forming apparatus 1 further includes a controller 80. The controller 80 may be a computer including a processor, a storage unit, an input device, a display device, and the like, to control the operation of the image forming apparatus 1. The storage unit of the controller 80 may store a control program that is to be executed by the processor to control various processes that operate the image forming apparatus 1 .
[0025] Hereinafter, the example cleaning device 70 will be described. The cleaning device 70 is provided downstream of the transfer region 13 in a conveyance direction (or rotational direction) C of the transfer belt 31. The cleaning device 70 removes residual (or non-transferred) toner particles that remain on the transfer belt 31 after the toner image has been transferred onto the sheet 5, at the transfer region 13.
[0026] With reference to FIGS. 2 to 4, the example cleaning device 70 includes a rotatable device 71 , a flexible sheet member (also referred to herein as an elastic plate-shaped member) 72, and a support 73. The rotatable device 71 rotates about a rotational axis AX that extends in a longitudinal direction (also referred to herein as a lateral direction or an MX-direction"). The rotatable device 71 includes a roller 81 and a rotatable shaft 82.
[0027] The roller 81 is a rigid roller made of a rigid material such as metal and having a substantially cylindrical shape. The roller 81 is located adjacent the flexible sheet member 72, so that an outer peripheral surface 81a of the roller 81 is in contact with or positioned in proximity to the flexible sheet member 72. The outer peripheral surface 81a forms a surface of the rotatable device 71 to be scraped by the flexible sheet member 72. As illustrated in FIG. 4, the outer peripheral surface 81a of the roller 81 contacts a surface of the transfer belt 31 . The roller 81 is disposed downstream of the transfer region 13 in the conveyance direction C of the transfer belt 31 , and receives power from an electric motor to rotate about the rotational axis AX in a state where the roller 81 contacts the surface of the transfer belt 31 at a point of contact. In some examples, the roller 81 rotates in a direction opposite the conveyance direction C of the transfer belt 31 at the point of contact. In other examples, the rotational direction of the roller 81 may be the same as the conveyance direction C of the transfer belt 31 at the point of contact.
[0028] The roller 81 receives an electric bias during an image formation operation, to draw the residual toner particles by electrostatic force, onto the outer peripheral surface 81a of the roller, in which the residual toner particles correspond to non-transferred toner particles that remain on the transfer belt 31 after the toner image has been transferred onto the sheet 5 at the transfer region 13.
[0029] The rotatable shaft 82 of the rotatable device 71 is coupled with opposite longitudinal ends of the roller 81 , to protrude outwardly from the opposite ends of the roller 81 , along the rotational axis AX. The rotatable shaft 82 of the rotatable device 71 is rotatably supported by a pair of brackets 92.
[0030] The flexible sheet member 72 is, for example, a scraper made of an elastic or flexible material such as metal or resin, to scrape off toner particles adhered to the outer peripheral surface 81a of the roller 81 . In some examples, the flexible sheet member 72 may be a thin sheet made of stainless steel, having a thickness of 0.06 mm to 0.1 mm. The flexible sheet member 72 has two opposite surfaces 72a and 72b. As illustrated in FIG. 2, the flexible sheet member 72 may include a main body 74 and a tongue 75. The main body 74 and the tongue 75 are integrally formed.
[0031] The main body 74 has a substantially rectangular planar shape so that a width of the main body 74 in the lateral direction is greater than a height of the main body 74 in the transverse or height direction. The main body 74 includes a contact edge portion 84, a rear edge portion 85, and a pair of side edge portions 86.
[0032] The contact edge portion 84 extends in the lateral direction (X- direction) parallel to the rotational axis AX. The contact edge portion 84 contacts the outer peripheral surface 81a of the roller 81 , to scrape off the toner particles adhered to the outer peripheral surface 81a of the rotating roller 81 , so as to separate the toner particles from the roller 81 .
[0033] The rear edge portion 85 is disposed opposite the contact edge portion 84, and extends substantially parallel to the contact edge portion 84. [0034] The pair of side edge portions 86 extend between the contact edge portion 84 and the rear edge portion 85 in a transverse direction (also referred to herein as a height direction or a "Z-direction") that is perpendicular (orthogonal) to the lateral direction of the main body 74.
[0035] The tongue 75 protrudes outward in the lateral direction, from the side edge portion 86 at each end of the main body 74. As illustrated in FIG. 3, the tongue 75 includes a first edge portion 87 and a second edge portion 88. The first edge portion 87 extends continuously from the contact edge portion 84 of the main body 74 in the lateral direction, and is disposed adjacent the rotatable shaft 82 of the rotatable device 71 . The second edge portion 88 is formed at a position between the contact edge portion 84 and the rear edge portion 85 in the transverse direction of the flexible sheet member 72, and is disposed to contact or is positioned in proximity to a first elongate portion 91a of a frame 91 that is described further below. Namely, the tongue 75 is fitted between the rotatable device 71 and the frame 91 , in order to fixedly position the flexible sheet member 72 relative to the rotatable device 71 .
[0036] The support 73 uses the restoring force of the flexible sheet member 72 generated by an elastic deformation, to support the flexible sheet member 72. With reference to FIGS. 2 and 5, the support 73 includes the frame 91 that extends in the lateral direction (X-direction) adjacent the rotatable device 71 , and the pair of brackets 92 to rotatably support the roller 81.
[0037] The frame 91 includes the first elongate portion 91a, a second elongate portion 91b, and a third elongate portion 91c. The first elongate portion 91a, the second elongate portion 91 b, and the third elongate portion 91c extend in the lateral direction (X-direction), and are arranged in the transverse or height direction (Z-direction) of the frame 91 . With reference to FIG. 3, the first elongate portion 91a is disposed between the rotatable device 71 and the second elongate portion 91 b, and the second elongate portion 91 b is disposed between the first elongate portion 91a and the third elongate portion 91c. When viewed in the Z- direction, the first elongate portion 91a overlaps the third elongate portion 91c, the first elongate portion 91 a is offset from the second elongate portion 91 b so as to have no overlap with the second elongate portion 91 b, and the second elongate portion 91 b at least partially overlaps the third elongate portion 91c. The frame 91 connects the first elongate portion 91a, the second elongate portion 91 b, and the third elongate portion 91 c at opposite longitudinal ends of the frame 91 . Each of the first elongate portion 91a, the second elongate portion 91b, and the third elongate portion 91c may have any suitable cross-sectional shape such as a rectangle, a polygon, or a circle.
[0038] The frame 91 forms a first slit 93 and a second slit 94 that extend in the X-direction. The first slit 93 is formed between the first elongate portion 91a and the second elongate portion 91 b of the frame 91 . The second slit 94 is formed between the second elongate portion 91b and the third elongate portion 91c of the frame 91 . The first slit 93 and the second slit 94 are openings through which the flexible sheet member 72 is passable, and extend parallel to each other. When viewed in the Z-direction, the first slit 93 and the second slit 94 may be formed at positions to overlap each other. The length of the first slit 93 and the second slit 94 in the X-direction may be set longer than the length of the roller 81 in the X-direction. Each of the first slit 93 and the second slit 94, may have any suitable shape in which the dimension (e.g., width) in the X-direction is greater than the dimension (e.g., height) in the Z-direction. As will be described later, the flexible sheet member 72 extends through the first slit and through the second slit substantially in the Z-direction, and is held in a bent state by the frame 91 . When the flexible sheet member 72 is inserted into the first slit 93 and into the second slit 94 in a bent state, the flexible sheet member 72 is biased against the frame 91 and the flexible sheet member 72 is held by the support 73 by the restoring force of the flexible sheet member 72.
[0039] With reference to FIG. 4, the first elongate portion 91a may include a first plate 91 a1 and a second plate 91 a2. The first plate 91 a1 extends on an X- Y plane. Namely, the first plate 91 a1 extends in the longitudinal direction (X- direction) of the frame 91 and in a depth direction (also referred to herein as a "Y- direction") of the frame 91 orthogonal to the longitudinal direction and the height direction (Z-direction) of the frame 91 . The second plate 91 a2 extends from the first plate 91 a1 toward the flexible sheet member 72 so as to form an angle with the first plate 91 a1 . Namely, the second plate 91 a2 is disposed to be tilted relative to the first plate 91 a1 , and the first elongate portion 91a has a substantially V- shape that is open to a flexible sheet member 72 side when viewed in the X- direction.
[0040] The pair of brackets 92 are coupled with opposite ends of the frame 91 in the X-direction. The frame 91 and the pair of brackets 92 may be integrally formed by pressing a sheet metal. The pair of brackets 92 extend from the longitudinal ends of the frame 91 in the Z-direction, and face each other in the X- direction. The pair of brackets 92 form respective through-holes 92h that extend in the X-direction so as to rotatably support the rotatable shaft 82 of the rotatable device 71 , which are inserted into the through-holes 92h. In addition, the pair of brackets 92 position the frame 91 to bias the flexible sheet member 72 against the outer peripheral surface 81 a of the roller 81.
[0041] In addition, the example cleaning device 70 may further include a seal 96 and a recovery container 98. The seal 96 is provided on the second plate 91 a2 to extend from the first elongate portion 91 a to the roller 81 . The seal 96 is made of, for example, an elastic or flexible material, and is disposed in close contact with the first surface 72a of the flexible sheet member 72. The seal 96 guides the residual toner particles (or non-transferred toner particles), which are scraped off from the roller 81 by the flexible sheet member 72, to the recovery container 98.
[0042] The recovery container 98 is open upward, and may be below the first elongate portion 91a to recover the residual toner particles that are scraped off from the roller 81 by the flexible sheet member 72 and are guided by the seal 96. The residual toner particles recovered by the recovery container 98 may be conveyed to a toner cartridge as a waste toner or a recycled toner via a conveyor device, for example, provided inside a housing of the image forming apparatus 1 . [0043] FIGS. 6 to 9 illustrate an example assembly procedure to assemble the cleaning device 70. With reference to FIGS. 6 and 7, when the flexible sheet member 72 is mounted to the support 73, the flexible sheet member 72 is inserted into the first slit 93 and into the second slit 94, so as to be fixed to the support 73. In addition, the position of the rear edge portion 85 of the flexible sheet member 72 is adjusted such that the contact edge portion 84 of the flexible sheet member 72 contacts the outer peripheral surface 81a of the roller 81 .
[0044] For example, with reference to FIG. 4, the flexible sheet member 72 is inserted into the first slit 93 and into the second slit 94 such that the first surface 72a of the flexible sheet member 72 contacts the first elongate portion 91a and the third elongate portion 91c, and so that the second surface 72b of the flexible sheet member 72 contacts the second elongate portion 91b. Since the first slit 93 and the second slit 94 are formed at positions to overlap each other when viewed in the Z-direction, the flexible sheet member 72 is bent in a thickness direction of flexible sheet member 72. Namely, the first elongate portion 91a, the second elongate portion 91b, and the third elongate portion 91c apply a bending force to the flexible sheet member 72 inserted into the first slit 93 and into the second slit 94, such that the flexible sheet member 72 is curved in a substantially S-shape. For example, the first elongate portion 91a and the third elongate portion 91c press the flexible sheet member 72 against the second elongate portion 91 b and the outer peripheral surface 81a of the roller 81 to form the S- shape. A restoring force is generated in the bent flexible sheet member 72, and the flexible sheet member 72 is biased against the first elongate portion 91a, the second elongate portion 91 b, and the third elongate portion 91c by the restoring force. Accordingly, the flexible sheet member 72 is supported by the support 73 via the biasing force.
[0045] With reference to FIGS. 8 and 9, a bearing 95 is inserted onto the rotatable shaft 82 of the rotatable device 71 , and the bearing 95 is disposed between the rotatable shaft 82 and the bracket 92. Accordingly, the rotatable device 71 is rotatably supported by the pair of brackets 92.
[0046] In the assembled cleaning device 70 assembled as illustrated in FIG. 9, the rotatable device 71 may receive power from an electric motor to rotate about the rotational axis AX, so that toner particles adhere to the outer peripheral surface 81a of the roller 81 and are scraped off by the flexible sheet member 72. A frictional force generated between the rotating roller 81 and the flexible sheet member 72 may apply a force on the flexible sheet member 72 directed away from to the roller 81 . In contrast, since the first elongate portion 91a, the second elongate portion 91b, and the third elongate portion 91c have respective contact surfaces to frictionally engage with the flexible sheet member 72 when the flexible sheet member 72 contacts the outer peripheral surface 81a of the roller 81 , the support 73 restricts the retraction of the flexible sheet member 72.
[0047] Further, since the tongue 75 of the flexible sheet member 72 is fitted between the rotatable device 71 and the frame 91 , when a force is applied to retract the flexible sheet member 72, the second edge portion 88 of the tongue 75 abuts the first plate 91 a1 of the first elongate portion 91a to prevent the retraction of the flexible sheet member 72 relative to the roller 81 . Namely, the tongue 75 is a stopper that prevents the retraction of the flexible sheet member 72, to fixedly position the main body 74 of the flexible sheet member 72 relative to the outer peripheral surface 81 a of the roller 81 .
[0048] A movement of toner particles to be recovered by the cleaning device 70 will be described with reference to FIG. 10.
[0049] The toner images primarily transferred from the photoconductors 40C, 40M, 40Y, and 40K onto the surface of the transfer belt 31 are conveyed in the conveyance direction C by the transfer belt 31 , and are secondarily transferred from the transfer belt 31 onto the sheet 5 at the transfer region 13 (of. FIG. 1 ). Toner particles that remain on the surface of the transfer belt 31 without having being transferred from the transfer belt 31 onto the sheet 5, are conveyed downstream the transfer region 13 toward the cleaning device 70.
[0050] When the toner particles on the transfer belt 31 move to a region facing the roller 81 , as illustrated in FIG. 10, the toner particles are recovered by the roller 81 by an electrostatic force. The toner particles adhered to the outer peripheral surface 81a of the roller 81 are rotated toward the flexible sheet member 72 by the rotation of the roller 81 , and are scraped off by the flexible sheet member 72 to be separated from the roller 81 . [0051] The toner particles separated from the roller 81 fall while sliding along the seal 96, and are recovered by the recovery container 98. The residual toner particles recovered by the recovery container 98 are conveyed into the toner cartridge as a waste toner or a recycled toner, for example, by a conveyor device. [0052] In the cleaning device 70, since the flexible sheet member 72 extends through the first slit and through the second slit in a state where the flexible sheet member 72 is bent in the thickness direction, the flexible sheet member 72 is biased against the frame 91 by the restoring force of the flexible sheet member 72. Accordingly, when the flexible sheet member 72 contacts the outer peripheral surface 81a of the roller 81 , a frictional force can be generated between the flexible sheet member 72 and the frame 91 to fix the flexible sheet member 72 to the support 73.
[0053] In order to suitably remove the toner particles adhered to the outer peripheral surface 81 a of the roller 81 , the flexible sheet member 72 is positioned to contact the outer peripheral surface 81a of the roller 81 with a suitable contact pressure. When the contact pressure of the flexible sheet member 72 against the outer peripheral surface 81 a of the roller 81 is too low, the toner particles adhered to the outer peripheral surface 81a may not be appropriately removed, and the cleaning performance of the cleaning device 70 is reduced. On the other hand, when the contact pressure of the flexible sheet member 72 against the outer peripheral surface 81a of the roller 81 is too great, the outer peripheral surface 81a of the roller 81 may be worn or damaged, and the lifespan of the roller 81 may be reduced. Therefore, the flexible sheet member 72 is set to apply a predetermined contact pressure against the outer peripheral surface 81a of the roller 81.
[0054] The contact pressure of the flexible sheet member 72 against the outer peripheral surface 81 a of the roller 81 depends on a distance Yref between a curvature fulcrum 72c that is a fulcrum of an elastic deformation of the flexible sheet member 72 and the contact edge portion 84 in the Y-direction, and a distance Zref between the curvature fulcrum 72c and the contact edge portion 84 in the Z-direction (of. FIG. 4). In order to cause the flexible sheet member 72 to contact the outer peripheral surface 81a of the roller 81 at the predetermined contact pressure (or within a predetermined range of the contact pressure), the distance Yref and the distance Zref are set within a predetermined range. The curvature fulcrum 72c is formed in a contact surface between the flexible sheet member 72 and the first elongate portion 91a. Namely, the first elongate portion 91 a is positioned to bias the flexible sheet member 72 against the outer peripheral surface 81a of the roller 81 at the predetermined contact pressure.
[0055] In some cleaning devices, the flexible sheet member such as a scraper may be fixed to a base with a screw, an adhesive, or the like. When the flexible sheet member is fixed to the base using a fixing member such as a screw, a dimensional error of the screw or a screw hole may cause a mounting error of the flexible sheet member. In addition, when the flexible sheet member is fixed to the base using an adhesive, the thickness of the adhesive may be non-uniform. The mounting error and the non-uniformity of the thickness of the adhesive may cause variation in the distance Yref and the distance Zref.
[0056] The example flexible sheet member 72 of the cleaning device 70 is supported by the support 73 via a frictional force generated between the flexible sheet member 72 and the frame 91 without using a fixing member such as a screw. Therefore, in the cleaning device 70, the number of components can be reduced relative to a cleaning device in which a fixing device fixes the scraper to the base. The cumulative tolerance during assembly can be reduced given a reduced number of components, so as to more easily set the distance Yref and the distance Zref within the predetermined range. Accordingly, the contact pressure of the contact edge portion 84 of the flexible sheet member 72 against the outer peripheral surface 81 a of the roller 81 can be set with greater accuracy, so as to inhibit a reduction in the lifespan of the roller 81 while achieving a suitable cleaning performance. Additionally, the cleaning device 70 can be more easily assembled given that the number of components is reduced.
[0057] In addition, in the example cleaning devices having a fixing member (e.g., a screw) that fixes a scraper to a base, a pressure difference may be generated between a fixed portion and a non-fixed portion of the scraper, and the contact edge portion of the scraper may be deformed in a wavy shape. The waviness formed in the contact edge portion may cause the contact pressure of the contact edge portion against the surface of the roller to vary in the longitudinal direction of the roller. In the example cleaning device 70, the flexible sheet member 72 is held at a uniform pressure in the X-direction, so as to suppress the formation of waviness in the contact edge portion 84 of the flexible sheet member 72, and to suppress variations in the contact pressure in the X-direction.
[0058] Additionally, in the cleaning device 70, the rear edge portion 85 of the flexible sheet member 72 is biased against the third elongate portion 91c, so as to prevent a vibration of the rear edge portion 85 from a frictional force between the roller 81 and the flexible sheet member 72, and thereby suppress a variation in the contact pressure of the flexible sheet member 72 that may be caused by the propagation of such vibration to the contact edge portion 84. Further, the generation of noise due to such vibration of the rear edge portion 85 is suppressed.
[0059] A modification example of the cleaning device will be described. Hereinafter, differences with the example cleaning device 70 described above will be mainly described, and overlapping description may be omitted.
[0060] With reference to FIG. 11 , an example cleaning device 170 includes an intermediate roller (also referred to herein as an abutting roller) 180 in addition to the roller 81 that is positioned as a distal roller in the example of FIG.11 .
[0061] The roller (distal roller) 81 is a rigid roller having, for example, a substantially cylindrical shape, and receives power from the electric motor to rotate about the rotational axis AX in a state in which the roller (distal roller) 81 is spaced away from the transfer belt 31. The intermediate roller 180 is disposed between the transfer belt 31 and the roller (distal roller) 81 . The intermediate roller 180 is, for example, a conductive sponge roller having a substantially cylindrical shape, and receives power from an electric motor to rotate about an axis in a state where the intermediate roller 180 contacts the surface of the transfer belt 31 and the surface of the roller (distal roller) 81. The intermediate roller 180 receives bias electric power to be charged during image formation. [0062] The intermediate roller 180 recovers the residual toner particles from the transfer belt 31 via an electrostatic force, in which the residual toner particles corresponds to the toner particles remaining on the transfer belt 31 without having been transferred on to the sheet 5 at the transfer region 13. When the toner particles recovered by the intermediate roller 180 move to a region facing the roller (or distal roller) 81 , the toner particles adhere to the roller (distal roller) 81 via an electrostatic force. A rotation of the roller (distal roller) 81 transfers the toner particles adhered thereto, to the region of the roller (distal roller) 81 facing (e.g., contacting) the flexible sheet member 72, where the adhered toner particles are scraped off from the roller (distal roller) 81 by the flexible sheet member 72.
[0063] In the example cleaning device 170, the toner particles on the transfer belt 31 are leveled by the intermediate roller 180 made of a conductive sponge, so as to increase the recovery rate of the toner particles on the transfer belt 31. The intermediate roller 180 may be a brush roller in some examples. [0064] Another modification example of the cleaning device will be described. Hereinafter, differences with the cleaning device 70 described above will be mainly described, and a overlapping description may be omitted.
[0065] With reference FIG. 12, an example cleaning device 270 may not include the rotatable device 71 nor the pair of brackets 92. The flexible sheet member 72 of the cleaning device 270 is supported by the frame 91 by extending through the first slit 93 and through the second slit 94. The flexible sheet member 72 directly contacts the surface of the transfer belt 31 to be biased against the surface of the transfer belt 31 with a predetermined contact pressure. The drive roller 37 that extends in the X-direction, rotates to cause the transfer belt 31 to rotate in the conveyance direction C. The residual toner particles adhered to the transfer belt 31 are carried to the region facing the flexible sheet member 72 by the rotation of the transfer belt 31, where the flexible sheet member 72 scrapes off the residual toner particles from the transfer belt 31.
[0066] Although various examples have been described in the specification, it should be understood that the arrangements and details may be modified in other examples.
[0067] For example, although examples have been described in which the support 73 supports the scraper for the cleaning device as the flexible sheet member 72, the support 73 may support a flexible sheet member other than a scraper. For example, the support 73 may support a developing plate for a developing device 20 (cf. FIG. 1 ), as the flexible sheet member 72, in which the developing plate contacts or extends in proximity to the developing roller 110. The developing plate may be made of an elastic material such as metal or resin, and may extend through the first slit 93 and through the second slit 94 to be biased against the frame 91 of the support 73, so as to be supported by the support 73. In some examples, the developing plate supported by the support 73 contacts a surface of the developing roller 110 of the developing device 20 at a constant contact pressure. Irregularities are formed on an outer peripheral surface of the developing roller 110 to impart a given roughness to the outer peripheral surface, so as to frictionally charge the developer, with the developing plate contacting the outer peripheral surface. When the developing roller 110 rotates about its axis, the developing plate limits the thickness of the toner carried on the developing roller 110 to a predetermined thickness, and uniformly charges the toner by friction. The developing plate supported by the support 73 contacts the outer peripheral surface of the developing roller 110 at a suitable contact pressure, to as to form a layer of the developer having a predetermined thickness, on the developing roller 110.
[0068] When the developing device 20 uses a two-component developer containing a toner and a carrier, the developing plate may be disposed in proximity to the surface of the developing roller 110 with a predetermined gap formed therebetween, instead of contacting the surface of the developing roller 110. In this example also, when the developing roller 110 rotates about its rotation axis, the developing plate limits the thickness of the toner carried on the developing roller 110 to the predetermined thickness.
[0069] It is to be understood that not all aspects, advantages and features described herein may necessarily be achieved by, or included in, any one particular example. Indeed, having described and illustrated various examples herein, it should be apparent that other examples may be modified in arrangement and detail is omitted.

Claims

1. An image forming apparatus comprising: a rotatable device to rotate about a rotational axis that extends in a longitudinal direction; a flexible sheet member located adjacent a surface of the rotatable device; and a support including a frame that extends in the longitudinal direction adjacent the rotatable device, wherein the frame forms a first slit and a second slit that extend in the longitudinal direction, and wherein the flexible sheet member extends through the first slit and through the second slit to bias the flexible sheet member against the frame.
2. The image forming apparatus according to claim 1 , comprising: an endless belt to rotate, wherein the rotatable device includes a rigid roller disposed between the endless belt and the flexible sheet member to collect toner particles from the endless belt, and wherein the flexible sheet member is positioned in contact with or in proximity to an outer peripheral surface of the rigid roller so as to scrape off the toner particles from the rigid roller.
3. The image forming apparatus according to claim 2, wherein the support includes a pair of brackets coupled with opposite longitudinal ends of the frame to rotatably support the rigid roller.
4. The image forming apparatus according to claim 1 , wherein the flexible sheet member includes a main body to contact the surface of the rotatable device, and a tongue that protrudes outward from the main body in the longitudinal direction, and wherein the tongue is fitted between the rotatable device and the frame, in order to fixedly position the flexible sheet member relative to the rotatable device.
5. The image forming apparatus according to claim 1 , wherein the frame includes a first elongate portion, a second elongate portion, and a third elongate portion that are arranged in a transverse direction of the frame, that is orthogonal to the longitudinal direction, wherein the first slit is formed between the first elongate portion and the second elongate portion, and wherein the second slit is formed between the second elongate portion and the third elongate portion, and wherein the first elongate portion, the second elongate portion, and the third elongate portion are positioned to bend the flexible sheet member so as to impart a restoring force to the flexible sheet member that biases the flexible sheet member against the frame.
6. The image forming apparatus according to claim 5, wherein the first elongate portion includes: a first plate that extends in the longitudinal direction and in a depth direction of the frame that is orthogonal to the longitudinal direction and to the transverse direction; and a second plate that extends from the first plate toward the flexible sheet member so as to form an angle with the first plate.
7. The image forming apparatus according to claim 5, wherein the first elongate portion of the frame is positioned to bias the flexible sheet member against the surface of the rotatable device.
8. The image forming apparatus according to claim 1 , wherein the rotatable device includes a developing roller that forms the surface, the surface of the developing roller to carry a developer.
9. An image forming apparatus comprising: an endless belt to rotate; a drive roller to rotate about a rotational axis that extends in a longitudinal direction, to rotate the endless belt; a flexible sheet member to contact a surface of the endless belt; and a support including a frame that extends in the longitudinal direction adjacent the endless belt, wherein the frame forms a first slit and a second slit that extend in the longitudinal direction, and wherein the flexible sheet member extends through the first slit and through the second slit to bias the flexible sheet member against the frame.
10. A cleaning device comprising: a support including a frame that extends in a longitudinal direction, wherein the frame forms a first slit and a second slit that extend in the longitudinal direction; and a flexible sheet member to contact a surface to be scraped, wherein the flexible sheet member extends through the first slit and through the second slit to bias the flexible sheet member against the frame.
11. The cleaning device according to claim 10, comprising: a roller that forms the surface to be scraped, wherein the support includes a pair of brackets coupled at opposite longitudinal ends of the frame, wherein the pair of brackets rotatably support the roller and position the frame to bias the flexible sheet member against the surface of the roller.
12. The cleaning device according to claim 11 , wherein the frame and the pair of brackets are integrally formed.
13. The cleaning device according to claim 10, wherein the frame includes a first elongate portion, a second elongate portion, and a third elongate portion that are arranged in a transverse direction of the frame, that is orthogonal to the longitudinal direction, wherein the first slit is formed between the first elongate portion and the second elongate portion, and the second slit is formed between the second elongate portion and the third elongate portion, and wherein the first elongate portion, the second elongate portion, and the third elongate portion are positioned to bend the flexible sheet member so as to impart a restoring force to the flexible sheet member that biases the flexible sheet member against the frame.
14. The cleaning device according to claim 13, wherein the first elongate portion includes: a first plate that extends in the longitudinal direction and in a depth direction of the frame that is orthogonal to the longitudinal direction and to the transverse direction; and a second plate that extends from the first plate toward the flexible sheet member so as to form an angle with the first plate.
15. The cleaning device according to claim 11 , wherein the flexible sheet member includes a main body to contact a surface of the roller, and a tongue that protrudes outward from the main body in the longitudinal direction, wherein the tongue is fixedly coupled to the frame to position the main body of the flexible sheet member relative to the surface of the roller.
PCT/US2022/012730 2021-07-08 2022-01-18 Image forming apparatus with flexible sheet member WO2023282936A1 (en)

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
JP2021113741A JP2023010003A (en) 2021-07-08 2021-07-08 Image forming apparatus having elastic plate-shaped member biased against frame
JP2021-113741 2021-07-08

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WO2023282936A1 true WO2023282936A1 (en) 2023-01-12

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Citations (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
WO2013142799A1 (en) * 2012-03-23 2013-09-26 Lexmark International, Inc. Cleaner unit for removing waste toner within an image forming device
US20140270840A1 (en) * 2013-03-15 2014-09-18 Canon Kabushiki Kaisha Image forming apparatus
US10007225B2 (en) * 2015-05-15 2018-06-26 Canon Kabushiki Kaisha Feeding device, process cartridge and image forming apparatus

Patent Citations (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
WO2013142799A1 (en) * 2012-03-23 2013-09-26 Lexmark International, Inc. Cleaner unit for removing waste toner within an image forming device
US20140270840A1 (en) * 2013-03-15 2014-09-18 Canon Kabushiki Kaisha Image forming apparatus
US10007225B2 (en) * 2015-05-15 2018-06-26 Canon Kabushiki Kaisha Feeding device, process cartridge and image forming apparatus

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