Fixing device and image forming apparatus

Abstract

To provide a fixing device that can reduce the quantity of transferred heat by providing a heat insulating space between members in contact with each other.SOLUTION: A fixing device 1 comprises pad members (base 33 and support plate 40) that are provided inside a fixing belt and form a nip part with a pressure member; and a pad holding member 50 that combines a first holding member 51 and a second holding member 52 to hold the pad members. The first holding member 51 has a first opposite part 51a, a first holding surface part 51b, and a first bent part 51c connecting the first opposite part 51a and the first holding surface part 51b to each other. The second holding member 52 has a second opposite part 52a, a second holding surface part 52b, and a second bent part 52c connecting the second opposite part 52a and the second holding surface part 52b to each other. The first bent part 51c and the second bent part 52c are different in curvature.SELECTED DRAWING: Figure 3

Description

[Technical Field]

[0001] The present disclosure relates to a fixing device that fixes an image on a sheet of paper and an image forming apparatus. [Background technology]

[0002] Conventionally, fixing devices used in electrophotographic image forming devices such as copiers and printers fix toner images by applying pressure and heat to paper on which an unfixed toner image has been formed. In recent years, fixing devices using an endless fixing belt have been proposed. In such fixing devices, a nip forming member is disposed inside the endless fixing belt, and a pressure roller is pressed against the nip forming member via the fixing belt to form a nip. Fixing devices are provided with a heat source for heating the fixing belt, and there are concerns about damage to components due to heat. Therefore, a method has been proposed for preventing thermal deformation of internal components without complicating the component configuration (see, for example, Patent Document 1). [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Publication No. 2020-76885 Summary of the Invention [Problem to be solved by the invention]

[0004] A conventional fixing device includes an endless fixing belt, a fixing belt holding member that holds the fixing belt at both ends, a pressure member that abuts the outer surface of the fixing belt, a nip forming member that is arranged inside the fixing belt and abuts against the pressure member via the fixing belt to form a nip, a nip support member that supports the nip forming member, a heat source that is arranged inside the fixing belt and heats the fixing belt, a reflective member that reflects radiant heat from the heat source, side plates that fix the fixing belt holding member and nip support member together, and a pressure mechanism that presses the pressure member against the nip forming member via the fixing belt, and the nip support member is formed as an integral member of at least two types of members with different thermal conductivities.

[0005] The nip support member in the fixing device described above includes a highly thermally conductive member that contacts the nip forming member and a highly rigid member that does not contact the nip forming member. The highly thermally conductive member has a higher thermal conductivity than the highly rigid member. This facilitates heat transfer between the nip forming member and the highly thermally conductive member, achieving a uniform temperature and reducing the temperature of the members. However, when heat escapes from the nip forming member and the temperature tends to decrease, there are problems such as a decrease in the heating efficiency of the heat source, a longer heating time, and increased power consumption.

[0006] The present disclosure has been made to solve the above-mentioned problems, and aims to provide a fixing device and an image forming apparatus that can reduce the amount of heat that transfers by providing an insulating space between contacting members. [Means for solving the problem]

[0007] A fixing device according to the present disclosure includes an endless fixing belt, a heat source for heating the fixing belt, a pressure member for applying pressure to the fixing belt from the outside, a pad member provided inside the fixing belt and forming a nip portion together with the pressure member, and a pad holding member for holding the pad member by combining a first holding member and a second holding member, wherein the first holding member has a first opposing portion facing the second holding member, a first holding surface portion facing the pad member, and a pad holding surface portion between the first opposing portion and the first holding member. The second holding member has a second opposing portion facing the first holding member, a second holding surface portion facing the pad member, and a second bending portion connecting the second opposing portion and the second holding surface portion, the first holding member and the second holding member are overlapped with the first opposing portion facing the second opposing portion, the first holding surface portion and the second holding surface portion extend in a direction away from each other, and the first bending portion and the second bending portion have different curvatures.

[0008] In the fixing device according to the present disclosure, the first holding surface portion and the second holding surface portion may have different areas that come into contact with the pad member.

[0009] In the fixing device according to the present disclosure, the distance from the first opposing portion to the first holding surface portion and the distance from the second opposing portion to the second holding surface portion may be different.

[0010] In the fixing device according to the present disclosure, the second bent portion may have a smaller curvature than the first bent portion, and the second retaining member may be configured to have an end bent portion at an end of the fixing belt in the width direction, the end bent portion having a smaller curvature than the second bent portion.

[0011] In the fixing device according to the present disclosure, the second bent portion may have a smaller curvature than the first bent portion, and the pad member may have a nip forming surface portion facing the pressure member, a pad abutment portion extending from the end of the nip forming surface portion toward the pad holding member, and a rib extending in the width direction of the fixing belt, and the rib may be configured to be positioned opposite the second bent portion.

[0012] The image forming apparatus according to the present disclosure is characterized by including the fixing device according to the present disclosure. [Effects of the Invention]

[0013] According to the present disclosure, the first bent portion and the second bent portion, which are arranged to face each other, have different curvatures, which creates a gap between them and the pad member. As a result, the contact area between the pad member and the pad holding member is reduced, and a heat insulating space is provided between them, thereby suppressing the amount of heat transferred to the pad holding member. [Brief explanation of the drawings]

[0014] [Figure 1] 1 is a schematic cross-sectional view showing a configuration of an image forming apparatus according to a first embodiment of the present disclosure. [Figure 2] 1 is a schematic cross-sectional view showing a configuration of a fixing device according to a first embodiment of the present disclosure. [Figure 3] FIG. 2 is a schematic cross-sectional view showing a base, a support plate, and a pad holding member. [Figure 4] FIG. 10 is a perspective view showing a second holding member according to a second embodiment of the present disclosure. [Figure 5] FIG. 5 is a schematic plan view of the second holding member shown in FIG. [Figure 6] FIG. 6 is a schematic cross-sectional view showing a cross section taken along the arrow AA in FIG. 5. DETAILED DESCRIPTION OF THE INVENTION

[0015] (First embodiment) Hereinafter, a fixing device and an image forming apparatus according to a first embodiment of the present disclosure will be described with reference to the drawings.

[0016] FIG. 1 is a schematic cross-sectional view showing the configuration of an image forming apparatus according to a first embodiment of the present disclosure.

[0017] The image forming device 100 is a multifunction device having a copy function, a scanner function, a facsimile function, and a printer function, and transmits an image of a document read by the image reading device 130 to an external device, and forms an image of a document read by the image reading device 130 or an image received from an external device in color or monochrome on a recording medium such as paper.

[0018] An original transport device 110 that is supported so as to be able to open and close freely is provided above the image reading device 130. The original transport device 110 transports one or more originals one by one. The image reading device 130 scans a scanning optical system 130b to read an original placed on an original placement table 130a, or reads an original transported by the original transport device 110 to generate image data.

[0019] The image forming apparatus 100 includes a fixing device 1, a developing device 2, a photosensitive drum 3, a drum cleaning device 4, a charger 5, an intermediate transfer belt device 7, a secondary transfer device 11, an optical scanning device 12, and a paper feed section 18.

[0020] Image forming apparatus 100 handles image data corresponding to color images using black (K), cyan (C), magenta (M), and yellow (Y), or monochrome images using a single color (e.g., black). Image forming apparatus 100 is provided with four developing devices 2, four photosensitive drums 3, four drum cleaning devices 4, and four chargers 5 for forming four types of toner images, and four image stations Pa, Pb, Pc, and Pd are configured corresponding to black, cyan, magenta, and yellow, respectively.

[0021] The charger 5 uniformly charges the surface of the photosensitive drum 3 to a predetermined potential. The optical scanning device 12 exposes the surface of the photosensitive drum 3 to light to form an electrostatic latent image. The developing device 2 develops the electrostatic latent image on the surface of the photosensitive drum 3 to form a toner image on the surface of the photosensitive drum 3. The drum cleaning device 4 removes and collects residual toner on the surface of the photosensitive drum 3. Through the series of operations described above, a toner image of each color is formed on the surface of each photosensitive drum 3.

[0022] The intermediate transfer belt device 7 includes an intermediate transfer roller 6, an endless intermediate transfer belt 71, an intermediate transfer drive roller 72, an intermediate transfer driven roller 73, and a cleaning device 9. Four intermediate transfer rollers 6 are provided inside the intermediate transfer belt 71 so as to form four types of toner images corresponding to each color. The intermediate transfer rollers 6 transfer the toner images of each color formed on the surface of the photosensitive drum 3 onto the intermediate transfer belt 71, which moves around in a circular motion.

[0023] The intermediate transfer belt 71 is stretched over an intermediate transfer drive roller 72 and an intermediate transfer driven roller 73. In the image forming apparatus 100, the toner images of each color formed on the surface of each photosensitive drum 3 are sequentially transferred and superimposed to form a color toner image on the surface of the intermediate transfer belt 71. The cleaning device 9 removes and collects waste toner remaining on the surface of the intermediate transfer belt 71 without being transferred to paper.

[0024] The secondary transfer device 11 sandwiches and transports a sheet of paper transported through the paper transport path 21 in the transfer nip portion TN between the secondary transfer roller 11a and the intermediate transfer belt 71. When the sheet of paper passes through the transfer nip portion TN, the toner image on the surface of the intermediate transfer belt 71 is transferred onto the sheet of paper, and the sheet of paper is transported to the fixing device 1.

[0025] The fixing device 1 includes a fixing belt 31 that rotates around an axis and a pressure roller 32 (an example of a pressure member). The fixing device 1 sandwiches a sheet of paper onto which a toner image has been transferred in a nip portion N between the fixing belt 31 and the pressure roller 32, and applies heat and pressure to fix the toner image to the sheet. Although not shown in FIG. 1, the fixing device 1 also includes components other than the fixing belt 31 and the pressure roller 32, and details of the fixing device 1 will be described later with reference to FIG. 2.

[0026] The paper feed unit 18 includes a paper feed cassette that holds recording media (paper) used for image formation, and is provided below the optical scanning device 12. The paper is pulled out of the paper feed unit 18 by a pickup roller 16 and transported to a paper transport path 21. The paper transported to the paper transport path 21 passes through the secondary transfer device 11 and the fixing device 1, and is then discharged to a paper output tray 19 by a discharge roller 17.

[0027] Conveyance rollers 13, registration rollers 14, and discharge rollers 17 are arranged on paper conveyance path 21. Conveyance rollers 13 facilitate the conveyance of paper. Registration rollers 14 convey paper at a speed equal to the process speed at which an image is formed on the paper. Registration rollers 14 are provided between paper feed unit 18 and secondary transfer device 11, and adjust the timing of paper conveyance so that the toner image is transferred to the paper by secondary transfer device 11. For example, registration rollers 14 wait (temporarily stop) while clamping paper conveyed from paper feed unit 18, and then start conveying the paper at a constant speed in synchronization with secondary transfer device 11.

[0028] When an image is to be formed on the back side of the paper in addition to the front side, the conveying direction of the paper is changed by discharge rollers 17, and the paper is conveyed to reversing conveying path 22. In reversing conveying path 22, the paper is guided up to registration rollers 14 in a reversed state by reversing conveying rollers 15. Image forming apparatus 100 forms an image on the back side of the paper guided to registration rollers 14 in the same manner as on the front side, and discharges the paper to discharge tray 19.

[0029] FIG. 2 is a schematic cross-sectional view showing the configuration of the fixing device according to the first embodiment of the present disclosure.

[0030] The fixing device 1 includes a fixing belt 31 and a pressure roller 32. As shown in Fig. 2, the fixing device 1 further includes, inside the fixing belt 31, a pad member (a base 33, a heat transfer plate 34, and a support plate 40), a sliding sheet 35, a pad holding member 50, a heating unit 36 ​​(an example of a heat source), and a reflecting plate 37. The fixing device 1 also includes, outside the fixing belt 31, a fixing temperature sensor 38 and a peeling plate 39.

[0031] The fixing belt 31 is an endless flexible belt formed in a substantially circular shape. The fixing belt 31 has a configuration in which a release layer is provided on the surface of a band-shaped base material formed of, for example, a synthetic resin such as polyimide or a metal such as nickel. The fixing belt 31 is provided so as to be rotatable about an axis that is perpendicular to the plane of the paper in FIG. 2. The axis direction of the fixing belt 31 is substantially parallel to the width direction W (see FIG. 4, described later) of the paper P being transported.

[0032] The pad member is formed of a base 33, a heat transfer plate 34 that covers the surface of the base 33 (particularly the pressure roller 32 side), and a support plate 40 that covers the back surface of the base 33. The base 33 is in the shape of a long plate extending along the axial direction of the fixing belt 31 and is formed of, for example, a synthetic resin. The heat transfer plate 34 is formed of, for example, a metal, and transfers heat evenly across the entire heat transfer plate 34. The support plate 40 is formed of, for example, a metal, and is attached to a pad holding member 50. The structures of the base 33 and the support plate 40 will be described later with reference to FIG. 3.

[0033] The sliding sheet 35 is fixed so as to cover the surface of the pad member (particularly the heat transfer plate 34), and is provided so as to be in sliding contact with the inner peripheral surface of the fixing belt 31. The pad member is fixed to the fixing belt 31 which rotates, and the sliding sheet 35 slides against the fixing belt 31. The sliding sheet 35 is impregnated with a lubricant to reduce the frictional force with the fixing belt 31.

[0034] The pad holding member 50 is a member that holds the pad member and the sliding sheet 35 while pressing them against the inner circumferential surface of the fixing belt 31. The pad holding member 50 is configured by combining a first holding member 51 and a second holding member 52, each having a substantially L-shaped cross section. The structure of the pad holding member 50 will be described later with reference to FIG. 3.

[0035] The heating unit 36 ​​is a member that heats the fixing belt 31, and is installed so as to extend along the axial direction of the fixing belt 31 (the width direction W described below). The heating unit 36 ​​is, for example, a lamp heater such as a halogen lamp. In this embodiment, the heating unit 36 ​​includes a main lamp 36a that heats the center of the fixing belt 31 in the width direction W, and sub-lamps 36b that heat both end portions of the fixing belt 31 in the width direction W. The operation of each of the main lamp 36a and the sub-lamp 36b is determined depending on the size of the paper P, etc. The fixing belt 31 is heated by the main lamp 36a and the sub-lamp 36b to, for example, 130°C to 180°C.

[0036] The reflecting plate 37 is a thin plate and is disposed so as to cover the surface of the pad holding member 50 on the heating unit 36 ​​side. The fixing belt 31 is configured to be heated efficiently by the reflecting plate 37.

[0037] The pressure roller 32 is disposed at a position facing the nip forming member with the fixing belt 31 sandwiched therebetween. The pressure roller 32 rotates about a rotation axis parallel to the axial direction of the fixing belt 31 and is disposed so as to extend substantially parallel to the fixing belt 31. At the nip N between the pressure roller 32 and the fixing belt 31, the fixing belt 31 is pressed against the pressure roller 32 by the nip forming member. The pressure roller 32 is configured, for example, by covering the surface of a cylindrical core material formed from a metal such as aluminum with an elastic material such as rubber.

[0038] A driving force from a driving source such as a motor (not shown) is transmitted to the pressure roller 32 via gears, etc. The pressure roller 32 receives this driving force and is driven to rotate, and as the pressure roller 32 is driven to rotate, the fixing belt 31 is driven to rotate in the direction opposite to the rotation direction of the pressure roller 32. The paper P passes through the nip portion N between the pressure roller 32 and the fixing belt 31 along the conveying direction S.

[0039] The fixing temperature sensor 38 detects the fixing temperature, which is the surface temperature of the fixing belt 31. The peeling plate 39 is disposed downstream of the nip portion N in the conveying direction S, and prevents the paper P from wrapping around the fixing belt 31.

[0040] In this embodiment, a configuration in which a heating section 36 is provided as a heat source is shown, but this is not limited to this. For example, instead of the heating section 36, a configuration in which a heat source such as a heater is housed within the base 33 of the pad member may be used.

[0041] FIG. 3 is a schematic cross-sectional view showing the base, the support plate, and the pad holding member.

[0042] Fig. 3 shows an enlarged view of the base 33, the support plate 40, and the pad holding member 50 extracted from the fixing device 1 shown in Fig. 2. The support plate 40 is provided between the base 33 and the pad holding member 50, and the pad holding member 50 presses the base 33 via the support plate 40.

[0043] In the base 33, a flat nip forming surface portion 33a faces the pressure roller 32, and a pad abutting portion 33b extends from an end of the nip forming surface portion 33a toward the pad holding member 50. A rib 33c extending toward the pad holding member 50 is provided at approximately the center of the nip forming surface portion 33a in the conveying direction S. The rib 33c extends long in the width direction W. The pad abutting portion 33b and the rib 33c extend (protrude) from the nip forming surface portion 33a by approximately the same length, and their upper ends abut against the support plate 40. Therefore, the nip forming surface portion 33a is not in direct contact with the support plate 40, and a gap is provided between the nip forming surface portion 33a and the support plate 40.

[0044] The first holding member 51 and the second holding member 52 are formed by bending a flat plate so that their cross sections are generally L-shaped. Specifically, the first holding member 51 has a flat plate-like first opposing portion 51a and a first holding surface portion 51b that extend perpendicular to each other, and the first opposing portion 51a and the first holding surface portion 51b are connected by a bent first bent portion 51c. Similarly to the first holding member 51, the second holding member 52 also has a flat plate-like second opposing portion 52a and a second holding surface portion 52b that extend perpendicular to each other, and the second opposing portion 52a and the second holding surface portion 52b are connected by a bent second bent portion 52c. The first holding member 51 and the second holding member 52 are overlapped with the first opposing portion 51a and the second opposing portion 52a facing each other, and when they are combined, the first holding surface portion 51b and the second holding surface portion 52b extend in directions away from each other. The first holding member 51 and the second holding member 52 are attached to the support plate 40 so that the first holding surface portion 51b and the second holding surface portion 52b face the pad member (particularly, the support plate 40). Figure 3 shows the first holding member 51 located on the right side of the drawing and the second holding member 52 located on the left side of the drawing, with the first holding surface portion 51b extending to the right and the second holding surface portion 52b extending to the left.

[0045] The support plate 40 is provided with a first protrusion 41 and a second protrusion 42 that protrude toward the pad holding member 50. The first protrusion 41 is provided on the side of the first holding member 51, and the second protrusion 42 is provided on the side of the second holding member 52. The first protrusion 41 and the second protrusion 42 may have different protruding heights in the width direction W. By providing a difference in the protruding heights in this way, the pressing force of the pad holding member 50 can be biased, allowing the appropriate parts to be held efficiently.

[0046] The first bent portion 51c and the second bent portion 52c have different curvatures. In this embodiment, the second bent portion 52c has a smaller curvature than the first bent portion 51c. Because the first bent portion 51c and the second bent portion 52c, which are arranged facing each other, have different curvatures, a gap (heat insulating space DK) is formed between the second bent portion 52c and the support plate 40. As a result, by reducing the contact area between the pad member and the pad holding member and providing the heat insulating space DK between them, the amount of heat transferred to the pad holding member can be suppressed. Furthermore, when the heating unit 36 ​​is provided, reducing the curvature of the second bent portion 52c facing the heating unit 36 ​​makes it easier to position the reflector 37 along the surface of the second holding member 52. This allows the distance between the reflector 37 and the heating unit 36 ​​to be kept constant, thereby uniformly heating the fixing belt 31.

[0047] Furthermore, the distance from the first opposing portion 51a to the first holding surface portion 51b is different from the distance from the second opposing portion 52a to the second holding surface portion 52b. In this embodiment, the second bent portion 52c has a smaller curvature than the first bent portion 51c, so the second bent portion 52c is provided over a wider range in the conveyance direction S than the first bent portion 51c, and the distance from the second opposing portion 52a to the second holding surface portion 52b is longer than the distance from the first opposing portion 51a to the first holding surface portion 51b. In this way, the first holding surface portion 51b and the second holding surface portion 52b extend in directions away from each other starting at different distances relative to the adjacent first opposing portion 51a and second opposing portion 52a, and the sizes of the areas not in contact with the support plate 40 are different.

[0048] The first opposing portion 51a and the second opposing portion 52a are located closer to the end of the support plate 40 than the center thereof in the conveying direction S (closer to the right end in FIG. 3 ), and the first holding surface portion 51b and the second holding surface portion 52b extend beyond the end of the support plate 40. Therefore, the first holding surface portion 51b and the second holding surface portion 52b have different contact areas with the support plate 40. In this embodiment, the second holding surface portion 52b has a larger contact area with the support plate 40 than the first holding surface portion 51b. Specifically, the first holding surface portion 51b contacts a portion of the first protrusion 41, and the second holding surface portion 52b contacts the entire second protrusion 42. In this way, the first holding member 51 and the second holding member 52 have different contact areas with the support plate 40, which makes it possible to adjust the transfer of heat and the holding force with respect to the support plate 40.

[0049] The above-mentioned rib 33c is provided at a position slightly shifted toward the first protrusion 41 from the center in the transport direction S, and at a position facing the second bent portion 52c. In this way, in the portion where the rib 33c is provided, a gap is provided between the pad holding member 50 and the second bent portion 52c, and this gap acts as a heat insulating space DK, making it possible to make it difficult for heat to be transmitted through the rib 33c.

[0050] (Second embodiment) Next, an image forming apparatus according to a second embodiment of the present disclosure will be described with reference to the drawings.

[0051] The second embodiment differs from the first embodiment in the shape of the second holding member 52. Note that the second embodiment has substantially the same configuration as the first embodiment shown in Figures 1 to 3, so a description thereof will be omitted and only the differences will be described.

[0052] 4 is a perspective view showing a second holding member in the second embodiment of the present disclosure, FIG. 5 is a schematic plan view of the second holding member shown in FIG. 4, and FIG. 6 is a schematic cross-sectional view showing the cross section at arrow AA in FIG. 5.

[0053] In the second embodiment, the second holding member 52 has a different shape at its end in the width direction W. Specifically, the second holding member 52 has an end bent portion 52e at its end in the width direction W, the end bent portion 52e having a smaller curvature than the second bent portion 52c, and an end holding surface portion 52d facing the support plate 40 extends from the end bent portion 52e. The end holding surface portion 52d extends in the conveying direction S to the same position as the tip of the second holding surface portion 52b. In other words, the second holding member 52 has the same length in the conveying direction S at both the central portion where the second bent portion 52c is provided and the end portion where the end bent portion 52e is provided. In this way, by providing the end bent portion 52e and creating a difference in the contact area with the support plate 40, it is possible to suppress heat transfer in the central portion while promoting heat transfer at the end portions, which are prone to overheating.

[0054] It should be noted that the embodiments disclosed herein are illustrative in all respects and are not intended to be limiting. Therefore, the technical scope of the present disclosure should not be interpreted solely by the above-described embodiments, but should be defined based on the claims. Furthermore, all modifications within the scope and meaning equivalent to the claims are included. [Explanation of symbols]

[0055] 1 Fixing device 31 Fixing belt 32 Pressure roller (an example of a pressure member) 33 Base 33a Nip forming surface 33b Pad contact part 33c Rib 34 Heat transfer plate 35 Sliding Sheet 36 Heating section (example of heat source) 40 Support plate 50 Pad holding member 51 first holding member 51a 1st opposing part 51b First holding surface part 51c 1st bending part 52 second holding member 52a Second opposing part 52b Second holding surface part 52c 2nd bending part 52d End holding surface 52e End bend 100 Image forming device DK Insulated Space S Conveying direction W width direction

Claims

1. an endless fixing belt; a heat source for heating the fixing belt; a pressure member that applies pressure to the fixing belt from the outside; a pad member provided inside the fixing belt and forming a nip portion together with the pressure member; a fixing device including a pad holding member that holds the pad member by combining a first holding member and a second holding member, the first holding member has a first opposing portion opposing the second holding member, a first holding surface portion facing the pad member, and a first bent portion connecting the first opposing portion and the first holding surface portion, the second holding member has a second opposing portion opposing the first holding member, a second holding surface portion facing the pad member, and a second bent portion connecting the second opposing portion and the second holding surface portion, the first holding member and the second holding member are overlapped with each other with the first opposing portion and the second opposing portion opposed to each other, and the first holding surface portion and the second holding surface portion extend in directions away from each other, The first bent portion and the second bent portion have different curvatures. A fixing device characterized by:

2. 2. The fixing device according to claim 1, The first holding surface portion and the second holding surface portion have different areas in contact with the pad member. A fixing device characterized by:

3. 2. The fixing device according to claim 1, a distance from the first opposing portion to the first holding surface portion and a distance from the second opposing portion to the second holding surface portion are different from each other; A fixing device characterized by:

4. 2. The fixing device according to claim 1, the second bent portion has a smaller curvature than the first bent portion, The second holding member has an end bent portion at an end in the width direction of the fixing belt, the end bent portion having a curvature smaller than that of the second bent portion. A fixing device characterized by:

5. 2. The fixing device according to claim 1, the second bent portion has a smaller curvature than the first bent portion, the pad member has a nip forming surface portion facing the pressure member, a pad abutment portion extending from an end of the nip forming surface portion toward the pad holding member, and a rib extending in the width direction of the fixing belt, The rib is provided at a position facing the second bent portion. A fixing device characterized by:

6. An image forming apparatus comprising the fixing device according to claim 1.

Images