Fixing device and image forming apparatus

Abstract

To provide a fixing device and an image forming apparatus in which a fixing belt is reliably cleaned.SOLUTION: A fixing device 20 comprises: a fixing belt 30 having a fixing surface 32; a pressing member 40; a fixing belt holder 22 having a first wall portion 24; a support film body 50 having a free portion 52; and a cleaning member 60. The support film body 50 is attached to the first wall portion 24. The cleaning member 60 is attached to the support film body 50. The free portion 52 includes an attachment section 54 and a sheet contact section 56. The cleaning member 60 contacts the fixing surface 32 by elasticity of the free portion 52. While the sheet contact section 56 is in contact with a sheet S, the cleaning member 60 is moved away from the fixing surface 32 against the elasticity of the free portion 52. When the sheet S separates from the sheet contact section 56, the sheet contact section 56 brings the cleaning member 60 close to the fixing surface 32 by elasticity of the free portion 52.SELECTED DRAWING: Figure 6

Description

[Technical Field]

[0001] The present invention relates to a fixing device and an image forming apparatus. [Background technology]

[0002] Patent Document 1 discloses a fixing unit for an electrophotographic device. The fixing unit of Patent Document 1 includes a fixing rotation member such as a fixing roller or fixing belt that fixes a toner image on an image surface of a sheet, a cleaning member that cleans the surface of the fixing rotation member, and a driving unit that moves the cleaning member. The cleaning member is provided so as to be movable between a cleaning position and a retracted position. In the fixing unit of Patent Document 1, the driving unit moves the cleaning member to the cleaning position and presses the cleaning member against the surface of the fixing rotation member. After cleaning the fixing rotation member, the fixing unit of Patent Document 1 moves the cleaning member to the retracted position. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Application Publication No. 5-107975 Summary of the Invention [Problem to be solved by the invention]

[0004] In the fixing device of Patent Document 1, when the fixing rotation member needs to be cleaned, an operator operates an external operation panel or the like to drive a drive means, which moves the cleaning member. Therefore, unless the operator performs the operation, the fixing rotation member remains uncleaned. If the fixing rotation member remains uncleaned, contaminants such as excess toner and paper dust that have adhered to the fixing rotation member from a sheet may adhere to other sheets and stain them. Furthermore, if contaminants adhere to a sheet, the toner image may not be properly fixed to the sheet.

[0005] The present invention has been made in view of the above-mentioned problems, and has an object to provide a fixing device in which the fixing belt is reliably cleaned. [Means for solving the problem]

[0006] A fixing device according to one aspect of the present invention includes a fixing belt, a pressure member, a fixing belt holder, a support film, and a cleaning member. The fixing belt has a fixing surface that contacts a sheet on which a toner image is formed and fixes the toner image to the sheet. The pressure member contacts the fixing surface of the fixing belt and applies pressure to the fixing belt, thereby forming a nip region between the fixing belt and the pressure member, sandwiching the sheet. The belt holder has a first wall portion and surrounds the fixing belt. The support film is attached to the first wall portion. The cleaning member is attached to the support film. The pressure member has a rotation axis. The pressure member rotates around the rotation axis to supply the sheet on which the toner image is formed to the nip region and discharge the sheet on which the toner image is fixed from the nip region. The support film has a free portion that is elastic and can move away from the first wall portion. The free portion has an attachment portion to which the cleaning member is attached and a sheet contact portion that contacts the sheet discharged from the nip area. The cleaning member, together with the attachment portion, moves away from the first wall portion due to the elasticity of the free portion and contacts the fixing surface of the fixing belt. While in contact with the sheet discharged from the nip area, the sheet contact portion, together with the attachment portion, approaches the first wall portion against the elasticity of the free portion, separating the cleaning member from the fixing surface of the fixing belt. When the sheet is discharged from the nip area and separates from the sheet contact portion, the sheet contact portion, together with the attachment portion, moves away from the first wall portion due to the elasticity of the free portion, separating the cleaning member from the fixing surface of the fixing belt.

[0007] According to one aspect of the present invention, there is provided an image forming apparatus including the fixing device described above and an image forming section that forms the toner image on the sheet, wherein the fixing device fixes the toner image formed on the sheet by the image forming section to the sheet. [Effects of the Invention]

[0008] According to the present invention, the fixing belt is reliably cleaned. [Brief explanation of the drawings]

[0009] [Figure 1] 1 is a diagram schematically illustrating a configuration of an image forming apparatus according to an embodiment of the present invention. [Figure 2] FIG. 2 is a cross-sectional view schematically illustrating a fixing device according to an embodiment of the present invention. [Figure 3] FIG. 2 is a perspective view schematically illustrating a support film and a cleaning member. [Figure 4] FIG. 2 is a perspective view schematically illustrating a cleaning member. [Figure 5] FIG. 2 is a diagram schematically illustrating the dimensional relationship between a fixing belt and a cleaning member. [Figure 6] 10A and 10B are diagrams illustrating a state in which the cleaning member is separated from the fixing surface of the fixing belt. [Figure 7] 10A and 10B are diagrams illustrating a state in which a cleaning member approaches a fixing surface of a fixing belt. DETAILED DESCRIPTION OF THE INVENTION

[0010] Hereinafter, an embodiment of a fixing device 20 and an image forming apparatus 10 according to the present invention will be described with reference to the drawings. In the drawings, the same or corresponding parts are designated by the same reference characters, and description thereof will not be repeated.

[0011] First, an image forming apparatus 10 according to an embodiment of the present invention will be described with reference to FIG. 1. FIG. 1 is a diagram schematically illustrating the configuration of the image forming apparatus 10 including a fixing device 20 according to an embodiment. The image forming apparatus 10 processes image data stored in a storage medium or image data transmitted from an external device to form an image on a sheet S. The image forming apparatus 10 is, for example, a multifunction peripheral having a printer function, a scanner function, and a copy function. The image forming apparatus 10 may form an image on a sheet S based on image data read from a document by the scanner function. The image forming apparatus 10 may also have a facsimile function. In this embodiment, the image forming apparatus 10 forms an image by electrophotography.

[0012] 1, in this embodiment, an image forming apparatus 10 includes a fixing device 20 and an image forming unit 12. The image forming unit 12 forms a toner image on a sheet S. The fixing device 20 fixes the toner image formed on the sheet S by the image forming unit 12 to the sheet S.

[0013] 1 further includes a feeding section 11, a conveying section 13, and a discharge section 16, in addition to a fixing device 20 and an image forming section 12. The feeding section 11 feeds a sheet S to the conveying section 13. The feeding section 11 includes, for example, a sheet tray that stores multiple sheets S, and a pickup roller that feeds the sheets S one by one from the sheet tray to the conveying section 13.

[0014] The conveying section 13 conveys the sheet S fed from the feeding section 11 to the discharge section 16 via the image forming section 12 and the fixing device 20. The conveying section 13 includes a plurality of guide plates 14 and a plurality of conveying rollers 15. The plurality of guide plates 14 and the plurality of conveying rollers 15 are arranged along a conveying path of the sheet S in the image forming apparatus 10. The guide plates 14 support the sheet S. The conveying rollers 15 rotate in contact with the sheet S supported by the guide plates 14, thereby conveying the sheet S along the conveying path.

[0015] The image forming unit 12 forms a toner image on the sheet S fed from the feeding unit 11. In the electrophotographic image forming apparatus 10, the image forming unit 12 includes, for example, a photosensitive drum, a charging device, an exposure device, a developing device, and a transfer device. The charging device charges the photosensitive drum. The exposure device outputs laser light to the charged photosensitive drum to form an electrostatic latent image on the photosensitive drum based on image data. The developing device forms a toner image on the photosensitive drum by supplying toner to the photosensitive drum on which the electrostatic latent image has been formed. The transfer device forms a toner image on the sheet S by transferring the toner image on the photosensitive drum to the sheet S.

[0016] The conveying unit 13 conveys the sheet S, on which the toner image has been formed by the image forming unit 12, to the fixing device 20. The fixing device 20 fixes the toner image to the sheet S by applying heat and pressure to the sheet S. The conveying unit 13 then conveys the sheet S, on which the toner image has been fixed, to the discharge unit 16. The discharge unit 16 discharges the sheet S to the outside of the image forming apparatus 10. The discharge unit 16 includes, for example, a pair of discharge rollers that rotate while sandwiching the sheet S, thereby moving the sheet S.

[0017] Next, the configuration of the fixing device 20 of this embodiment will be described with reference to FIGS. 1 and 2. FIG. 2 is a schematic cross-sectional view of the fixing device 20 according to this embodiment of the present invention. In FIG. 1, the sheet S is conveyed from the image forming unit 12, which is disposed upstream of the fixing device 20 in the conveyance path, to the fixing device 20. The sheet S is then conveyed from the fixing device 20 to the discharge unit 16, which is disposed downstream of the conveyance path relative to the fixing device 20. In FIG. 2, the fixing device 20 is illustrated with the right side being the upstream side of the conveyance path and the left side being the downstream side of the conveyance path. Therefore, the sheet S is conveyed from the right side of FIG. 2 through the fixing device 20 to the left side. The sheet S is conveyed from the image forming unit 12, which is disposed to the right of the area shown in FIG. 2, to the fixing device 20, guided on a guide plate 14 by a conveyance roller 15 of a conveyance unit 13.

[0018] 2, the fixing device 20 includes a fixing belt 30, a pressure member 40, a fixing belt holder 22, a support film 50, and a cleaning member 60. The fixing device 20 in FIG. 2 further includes a heating unit 34 and a pressing member 36.

[0019] The fixing belt 30 has a fixing surface 32 that comes into contact with the sheet S on which a toner image has been formed (the sheet S transported from the image forming unit 12 to the fixing device 20 in FIG. 1 ) and fixes the toner image to the sheet S. The fixing belt 30 is, for example, an endless belt having a substantially cylindrical shape. The fixing belt 30 rotates in the circumferential direction of the cylindrical shape. In FIG. 2 , the fixing surface 32 is the outer circumferential surface of the fixing belt 30 (the circumferential surface of the cylindrical shape). For example, the fixing belt 30 can be a substantially cylindrical heat-resistant resin layer made of polyimide or the like, with a fluororesin layer formed on the outer periphery. Alternatively, a metallic cylindrical tube made of aluminum, nickel, or the like may be used instead of the heat-resistant resin layer. If a release film made of a material with high release properties and heat resistance, such as fluororesin, is arranged on the outer periphery of the metallic cylindrical tube, the release film functions as the fixing belt 30.

[0020] 2, the heating unit 34 and the pressing member 36 are disposed inside (on the inner circumferential side of) the fixing belt 30. The heating unit 34 is, for example, a heater that generates heat when supplied with power. The pressing member 36 is, for example, a member made of heat-resistant resin. The pressing member 36 extends in a direction from the fixing belt 30 toward the pressing member 40, and presses the fixing belt 30 toward the pressing member 40 from the inside. The heating unit 34 heats the fixing belt 30 via the pressing member 36.

[0021] The fixing belt holder 22 in FIG. 2 has multiple walls including a first wall 24. The fixing belt holder 22 surrounds the fixing belt 30 with the multiple walls. In FIG. 2, the first wall 24 is located to the left of the fixing belt 30 in the drawing. Since the left side in the drawing is the downstream side of the transport path, the first wall 24 located to the left of the fixing belt 30 is a wall located downstream of the fixing belt 30 in the transport direction. The support film body 50 is attached to the first wall 24. The cleaning member 60 is attached to the support film body 50.

[0022] The pressure member 40 contacts the fixing surface 32 of the fixing belt 30 and applies pressure to the fixing belt 30, thereby forming a nip region 45 between the pressure member 40 and the fixing belt 30, sandwiching the sheet S. The pressure member 40 has a rotation axis 41 and rotates about the rotation axis 41. By rotating about the rotation axis 41, the pressure member 40 supplies the sheet S, on which a toner image has been formed, to the nip region 45. The pressure member 40 then ejects the sheet S, on which the toner image has been fixed, from the nip region 45. The rotation axis 41 of the pressure member 40 extends in a width direction B that intersects with the direction of gravity A. The width direction B, which is parallel to the rotation axis 41, intersects with the plane of the paper in FIG. 2. Also, in FIG. 2, the direction of the force (pressure force P) with which the pressure member 40 applies pressure to the fixing belt 30 is inclined with respect to the direction of gravity A. Because the direction of the pressure force P applied by the pressure member 40 is inclined with respect to the direction of gravity A, the nip region 45 is an area inclined with respect to the direction of gravity A.

[0023] 2, pressure member 40 is a roller. The roller of pressure member 40 includes, for example, a cylindrical elastic layer supported by rotation axis 41 and a release layer disposed on the outer peripheral surface of the cylindrical elastic layer. The release layer disposed on the outer peripheral surface of pressure member 40 is formed of, for example, a heat-resistant film made of fluororesin. Pressure member 40 is disposed so that the release layer on the outer peripheral surface comes into contact with fixing surface 32 of fixing belt 30 and applies pressure to fixing belt 30.

[0024] 2, the area of the fixing belt 30 that comes into contact with the pressure member 40 and receives pressure from the pressure member 40 is curved to fit the outer peripheral surface of the pressure member 40. The portion of the fixing belt 30 that is curved to fit the outer peripheral surface of the pressure member 40 is the nip region 45.

[0025] 2, the pressure member 40 rotates in the counterclockwise direction CCW around the rotation axis 41. When the pressure member 40 rotates in the counterclockwise direction CCW, the fixing belt 30 in contact with the pressure member 40 rotates in the clockwise direction CW following the rotation of the pressure member 40.

[0026] Since the right side in the drawing is the upstream side of the conveying path, the sheet S on which the toner image has been formed in the image forming unit 12 is conveyed from the right side in the drawing on the guide plate 14 to the fixing device 20. The sheet S conveyed from the right side in the drawing to the fixing device 20 is supplied to the nip region 45 by the pressure member 40 rotating in the counterclockwise direction CCW.

[0027] When the sheet S passes through the nip region 45, the toner image formed on the sheet S is heated and melted by the heating unit 34 through the fixing belt 30. Then, the sheet S is sandwiched and pressed between the pressing member 36 and the pressure member 40 inside the fixing belt 30, and the toner image is fixed to the sheet S.

[0028] The sheet S, on which the toner image has been fixed in the nip area 45, is discharged from the nip area 45 to the left side in the figure by the pressure member 40, which rotates in the counterclockwise direction (CCW). The sheet S discharged from the nip area 45 is transported further to the right side in the transport direction (further left than the area in the figure) of the fixing device 20. The sheet S, on which the toner image has been fixed in the fixing device 20, is transported to the discharge section 16 by the transport section 13 in FIG. 1 and discharged to the outside of the image forming apparatus 10.

[0029] 2, guide plate 14, which guides sheet S along the conveying path, is inclined with respect to the direction of gravity A. Guide plate 14 guides sheet S from below in the direction of gravity A to nip area 45. Therefore, when pressure member 40 supplies sheet S to nip area 45, it supplies sheet S from below in the direction of gravity A relative to nip area 45. When pressure member 40 discharges sheet S from nip area 45, it discharges sheet S upward in the direction of gravity A relative to nip area 45.

[0030] When the sheet S passes through the nip region 45, substances (such as paper dust or toner powder) attached to the sheet S adhere to the fixing surface 32 of the fixing belt 30 as contaminants 69. The fixing device 20 in FIG. 2 includes a support film 50 and a cleaning member 60 for cleaning the contaminants 69.

[0031] The support film body 50 and the cleaning member 60 will be described with reference to Figures 2, 3, 4, and 5. Figure 3 is a perspective view that schematically shows the support film body 50 and the cleaning member 60. Figure 4 is a perspective view that schematically shows the cleaning member 60. Figure 5 is a diagram that schematically shows the dimensional relationship between the fixing belt 30 and the cleaning member 60.

[0032] As shown in FIG. 3, the support film 50 is a thin film-like member. The support film 50 extends in a width direction B parallel to the rotation axis 41 of the pressure member 40. The support film 50 has a fixed portion 51 and a free portion 52. The free portion 52 has an attachment portion 54 and a sheet contact portion 56. The attachment portion 54 and the sheet contact portion 56 are connected to each other. The fixed portion 51 is an end portion of the support film 50. As shown in FIG. 2, the fixed portion 51 is fixed to the first wall portion 24 by adhesive or the like. By fixing the fixed portion 51 to the first wall portion 24, the support film 50 is attached to the first wall portion 24.

[0033] The free portion 52 is not fixed to the first wall portion 24 and can move away from the first wall portion 24. The free portion 52 is elastic. The free portion 52 is made of a synthetic resin such as PET (PolyEthylene Terephthalate). It is preferable that at least the free portion 52 of the support film 50 is elastic, but the fixed portion 51 may also be elastic. Therefore, the entire support film 50 may be made of PET.

[0034] The cleaning member 60 is attached to the attachment portion 54, which is a part of the free portion 52, by adhesion, melting, or the like. As shown in FIGS. 3 and 4, the cleaning member 60 is a member having a thickness greater than that of the support film body 50. The cleaning member 60 is made of, for example, a heat-resistant sponge such as a silicone sponge. The cleaning member 60 in FIG. 4 has a wedge-shaped cross section. As shown in FIGS. 3 and 4, the cleaning member 60 has an inclined surface 61 that is inclined with respect to the attachment portion 54. The inclined surface 61 has a plurality of ribs 62 that extend in the width direction B. The inclined surface 61 and the ribs 62 prevent the soiled matter 69 from returning to the fixing belt 30.

[0035] 2, the cleaning member 60 moves away from the first wall portion 24 together with the attachment portion 54 due to the elasticity of the free portion 52. Because the first wall portion 24 is located downstream of the fixing belt 30 in the transport direction, the elastic force F of the free portion 52 acting to move the cleaning member 60 away from the first wall portion 24 acts in a direction toward the upstream side in the transport direction (the right side in FIG. 2). The cleaning member 60, which has moved away from the first wall portion 24 together with the attachment portion 54 due to the elasticity of the free portion 52, receives the elastic force F in the direction toward the fixing belt 30 and comes into contact with the fixing surface 32 of the fixing belt 30.

[0036] Furthermore, since the first wall portion 24 to which the support film body 50 is attached is inclined with respect to the direction of gravity A, the cleaning member 60 attached to the support film body 50 is subjected to gravity g in a direction toward the fixing surface 32 of the fixing belt 30.

[0037] 2 and 3, the sheet contact portion 56, which is part of the free portion 52, is the end portion of the support film body 50 opposite the fixed portion 51. In FIG. 2, the sheet contact portion 56 is the tip end of the free portion 52 in the direction of gravity A. When the sheet S is discharged from the nip region 45, the sheet contact portion 56 comes into contact with the discharged sheet S.

[0038] 2, when the sheet contact portion 56 is not in contact with the sheet S, the cleaning member 60 is away from the first wall portion 24 and in contact with the fixing surface 32. When the fixing belt 30 rotates in the clockwise direction CW with the cleaning member 60 in contact with the fixing surface 32, the soiling 69 adhering to the fixing belt 30 adheres to the cleaning member 60 and is cleaned off the fixing belt 30.

[0039] When an image is formed on the sheet S, the fixing belt 30 is heated by the heating unit 34 and rotated together with the pressure member 40 (preheating operation) in order to preheat the fixing belt 30 before the sheet S is transported to the fixing device 20. During the preheating operation, the fixing belt 30 rotates while contacting the cleaning member 60, so that contaminants 69 are cleaned from the fixing belt 30 before the sheet S is supplied to the nip area 45. Therefore, the sheet S is prevented from being contaminated by the contaminants 69.

[0040] The cleaning member 60 is brought into contact with the fixing surface 32 by the elasticity of the support film body 50. Therefore, even without any operation by an operator, the cleaning member 60 reliably contacts the fixing surface 32. Then, the fixing belt 30 is reliably cleaned simply by rotating the fixing belt 30.

[0041] Furthermore, because the cleaning member 60 is subjected to gravity g in the direction toward the fixing surface 32 of the fixing belt 30, the cleaning member 60 is subjected to a force toward the fixing surface 32 not only by the elastic force F but also by gravity g. Therefore, the elastic force F pressing the cleaning member 60 against the fixing surface 32 can be minimized. If the elastic force F pressing the cleaning member 60 against the fixing surface 32 is minimized, the friction generated between the cleaning member 60 and the fixing belt 30 is reduced, and wear of the cleaning member 60 and the fixing belt 30 is prevented.

[0042] As shown in FIGS. 3 and 4 , the inclined surface 61 of the cleaning member 60, which is inclined relative to the mounting portion 54, is more distant from the mounting portion 54 at positions farther from the sheet contact portion 56. The inclined surface 61 is also closer to the mounting portion 54 at positions closer to the sheet contact portion 56. Therefore, the thickness of the inclined surface 61 decreases as it approaches the sheet contact portion 56 (the leading end in the direction of gravity A). Contaminants 69 adhering to the cleaning member 60 from the fixing surface 32 adhere between the ribs 62 of the inclined surface 61 and move along the inclined surface 61 due to gravity g. Because the thickness of the inclined surface 61 decreases as it approaches the sheet contact portion 56, the contaminants 69 move further away from the fixing surface 32 as they approach the sheet contact portion 56 (leading end). Therefore, the contaminants 69 cleaned from the fixing surface 32 also move further away from the fixing surface 32 on the cleaning member 60, preventing the cleaned contaminants 69 from returning to the fixing surface 32.

[0043] 5, the dimension (width dimension L) of the portion of the cleaning member 60 that contacts the fixing surface 32 in the width direction B parallel to the rotation axis 41 is equal to or larger than the dimension (sheet width D) of the sheet S in the width direction B. In FIG. 5, the width dimension L of the cleaning member 60 is larger than the dimension of the entire fixing belt 30 in the width direction B. If the width dimension L of the cleaning member 60 is larger than the dimension of the entire fixing belt 30 in the width direction B, the cleaning member 60 can clean contaminants 69 from the entire fixing belt 30. If the cleaning member 60 is at least equal to or larger than the sheet width D (the dimension in the width direction B of the largest sheet S that may be used), it can clean contaminants 69 that may adhere to the sheet S and prevent the contaminants 69 from adhering to the sheet S.

[0044] Next, referring to Fig. 6, it will be described how the cleaning member 60 separates from the fixing surface 32 of the fixing belt 30 when the sheet S comes into contact with the sheet contact portion 56. Fig. 6 is a diagram schematically illustrating a state in which the cleaning member 60 separates from the fixing surface 32 of the fixing belt 30.

[0045] As shown in FIG. 6, when the sheet S is discharged from the nip area 45, the sheet contact portion 56 comes into contact with the discharged sheet S. While the sheet contact portion 56 is in contact with the sheet S being discharged from the nip area 45, it receives a force directed toward the downstream side in the conveyance direction of the sheet S (to the left in the drawing). Because the first wall portion 24 is located downstream of the fixing belt 30 in the conveyance direction, the sheet contact portion 56 receives a force from the sheet S in a direction moving toward the first wall portion 24. Meanwhile, the cleaning member 60 receives a force in a direction moving away from the first wall portion 24 (to the right in the drawing) due to the elasticity of the free portion 52. Furthermore, because the pressure member 40 discharges the sheet S upward in the direction of gravity A relative to the nip area 45, the sheet contact portion 56 receives a force in a direction opposite to gravity g (upward in the direction of gravity A) while in contact with the sheet S. Therefore, while the sheet contact portion 56 is in contact with the sheet S, the sheet contact portion 56, together with the attachment portion 54 connected to the sheet contact portion 56, approaches the first wall portion 24 against the elasticity of the free portion 52 (and gravity g). The sheet contact portion 56, together with the attachment portion 54 to which the cleaning member 60 is attached, approaches the first wall portion 24, thereby separating the cleaning member 60 from the fixing surface 32 of the fixing belt 30.

[0046] Therefore, while the sheet S passes through the nip area 45, the cleaning member 60 is separated from the fixing surface 32. By separating the cleaning member 60 from the fixing surface 32, it is possible to prevent the cleaning member 60 and the fixing belt 30 from being worn out due to continued contact of the cleaning member 60 with the fixing surface 32. Furthermore, because the cleaning member 60 is separated from the fixing surface 32 simply by discharging the sheet S from the nip area 45, the cleaning member 60 can be reliably moved without any operation by the operator.

[0047] Next, referring to Fig. 7, it will be described how the cleaning member 60 approaches the fixing surface 32 of the fixing belt 30 when the sheet S leaves the sheet contact portion 56. Fig. 7 is a diagram schematically illustrating a state in which the cleaning member 60 approaches the fixing surface 32 of the fixing belt 30.

[0048] 7, when the sheet S is discharged from the nip region 45 and separates from the sheet contact portion 56, the sheet contact portion 56 is no longer subjected to the force opposing the elasticity of the free portion 52 and the force opposing gravity g from the sheet S. Then, the sheet contact portion 56, together with the attachment portion 54 connected to the sheet contact portion 56, separates from the first wall portion 24 due to the elasticity of the free portion 52 (and gravity g) and approaches the fixing surface 32 of the fixing belt 30. The sheet contact portion 56, together with the attachment portion 54 to which the cleaning member 60 is attached, approaches the fixing surface 32 of the fixing belt 30, thereby causing the cleaning member 60 to approach the fixing surface 32 of the fixing belt 30.

[0049] Therefore, after sheet S has passed through nip area 45, cleaning member 60, which had been separated from fixing surface 32, comes into contact with fixing surface 32 again, cleaning fixing belt 30. By cleaning fixing belt 30 after sheet S has passed through nip area 45, soiling 69 adhering to fixing surface 32 from sheet S that has passed through nip area 45 is immediately cleaned. Furthermore, fixing belt 30 is reliably cleaned without any operation by an operator.

[0050] The embodiments of the present disclosure have been described above with reference to the drawings. However, the present disclosure is not limited to the above embodiments and can be implemented in various forms without departing from the spirit and scope of the present disclosure. The drawings mainly show each component in a schematic manner for ease of understanding, and the thickness, length, number, spacing, etc. of each illustrated component may differ from the actual components due to the convenience of creating the drawings. Furthermore, the materials, shapes, dimensions, etc. of each component shown in the above embodiments are merely examples and are not particularly limited, and various modifications are possible within a scope that does not substantially deviate from the configuration of the present disclosure. [Industrial Applicability]

[0051] The present invention provides a fixing device and an image forming apparatus, and has industrial applicability. [Explanation of symbols]

[0052] 10 Image forming device 11 Feeding section 12 Image forming unit 13 Conveying section 14 Guide plate 15 Transport roller 16 Discharge section 20 Fixing device 22 Fixing belt holder 24 1st wall 30 Fixing belt 32 Fixing surface 34 Heating unit 36 Pressing member 40 Pressure member 41 Rotation axis center 45 nip area 50 Support membrane body 51 Fixed part 52 Free section 54 Mounting part 56 Seat contact area 60 Cleaning material 61 Slope 62 Ribs 69 Defaced Items S seat

Claims

1. a fixing belt having a fixing surface for contacting a sheet on which a toner image is formed to fix the toner image to the sheet; a pressure member that contacts the fixing surface of the fixing belt and applies pressure to the fixing belt to form a nip region between the fixing belt and the pressure member, and the sheet is sandwiched between the pressure member and the fixing belt; a fixing belt holder having a first wall portion and surrounding the fixing belt; a support film attached to the first wall; a cleaning member attached to the support film; Equipped with the pressure member has a rotation axis, the pressure member rotates around the rotation axis to supply the sheet on which the toner image has been formed to the nip area and discharge the sheet on which the toner image has been fixed from the nip area; the support film has a free portion that is capable of separating from the first wall portion and exhibits elasticity; the free portion has an attachment portion to which the cleaning member is attached and a sheet contact portion that comes into contact with the sheet discharged from the nip area, the cleaning member separates from the first wall portion together with the attachment portion due to the elasticity of the free portion and comes into contact with the fixing surface of the fixing belt; the sheet contact portion, while in contact with the sheet discharged from the nip region, approaches the first wall portion together with the attachment portion against the elasticity of the free portion to separate the cleaning member from the fixing surface of the fixing belt; When the sheet is discharged from the nip area and separates from the sheet contact portion, the sheet contact portion separates from the first wall portion together with the mounting portion due to the elasticity of the free portion, bringing the cleaning member closer to the fixing surface of the fixing belt.

2. the pressure member supplies the sheet to the nip region from below in the direction of gravity and discharges the sheet to the nip region from above in the direction of gravity; the first wall portion of the fixing belt holder is inclined with respect to the direction of gravity, the cleaning member is subjected to gravity in a direction toward the fixing surface of the fixing belt, The fixing device according to claim 1 , wherein the sheet contact portion receives a force from the sheet in a direction opposite to gravity while in contact with the sheet discharged from the nip region.

3. 2. The fixing device according to claim 1, wherein a dimension of the cleaning member in a width direction parallel to the rotation axis of the fixing member, the portion of the cleaning member that comes into contact with the fixing surface, is equal to or greater than a dimension of the sheet in the width direction.

4. the cleaning member has an inclined surface inclined relative to the attachment portion, The fixing device according to claim 1 , wherein the inclined surface is formed with a plurality of ribs extending in a width direction parallel to the rotation axis.

5. The fixing device according to any one of claims 1 to 4, an image forming unit that forms the toner image on the sheet; Equipped with The fixing device fixes the toner image formed on the sheet by the image forming section to the sheet.

Images