Fixing apparatus and image forming apparatus

Abstract

To provide a fixing device and an image forming apparatus that can provide heat resistance to a part to be regulated and prevent wear of the part to be regulated and / or a regulation part.SOLUTION: A fixing belt 31 is provided with a heat resistant member 42a on its inner peripheral surface 311 and further provided with a slidable member 42b on the heat resistant member 42a, a regulation part 43 is composed of a step part 43a, a part to be regulated 42 is composed of the heat resistant member 42a and the slidable member 42b, and at least part of a side face 42b1 of the slidable member 42b faces the step part 43a. Alternatively, the step part 44 is provided with the slidable member 43b, the fixing belt 31 is provided with the heat resistant member 42a on the inner peripheral surface 311, the regulation part 43 is composed of the slidable member 43b, the part to be regulated 42 is composed of the heat resistant member 42a, and a side face 42a1 of the heat resistant member 42a faces a side face 43b1 of the slidable member 43b.SELECTED DRAWING: Figure 6A

Description

Technical Field

[0001] The present invention relates to a fixing device and an image forming apparatus such as a copying machine, a multifunction peripheral, a printer, and a facsimile apparatus.

Background Art

[0002] As a fixing device for fixing an unfixed toner image onto a sheet such as a recording paper, there is one including a holding member fixed to a fixing device main body and a fixing belt provided rotatably around a rotation axis on an outer peripheral surface of the holding member.

[0003] In such a fixing device, due to various factors, movement (shift) in the rotation axis direction of the fixing belt occurs. Then, the end portion of the fixing belt and / or the wall surface of the holding member facing the fixing belt may be damaged or broken.

[0004] In order to solve such inconveniences, conventionally, a restricting portion is provided on the outer peripheral surface of the holding member facing the fixing belt, and a restricted portion is provided on the inner peripheral surface of the fixing belt facing the holding member, and a fixing device has been proposed in which the movement of the fixing belt in the rotation axis direction is restricted by the restricted portion coming into contact with the restricting portion (see, for example, Patent Document 1).

[0005] Specifically, in Patent Document 1, as the restricted portion, a meandering prevention member made of a material having excellent heat resistance such as silicone rubber or fluorine rubber is used.

Prior Art Documents

Patent Documents

[0006]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0007] However, although the restricted part used in the fixing device described in Patent Document 1 can be made heat resistant, sliding properties (wear resistance) are not considered, and when the restricted part comes into contact with the restricting part, the restricted part and / or the restricting part are prone to wear.

[0008] Therefore, the objective is to provide a fixing device and an image forming apparatus that can provide heat resistance to the restricted part and suppress wear of the restricted part and / or the restricted part. [Means for solving the problem]

[0009] To solve the above problems, the present invention provides the following: The mounting device and To provide an image forming apparatus.

[0010] (1 ) mounting device The present invention relates to ru The fixing device comprises a retaining member fixed to the fixing device body, and a fixing belt rotatably mounted on the outer circumferential surface of the retaining member around a rotation axis, wherein the outer circumferential surface of the retaining member has a restricting portion facing the fixing belt, and the inner circumferential surface of the fixing belt has a restricted portion facing the retaining member, and the restricted portion contacts the restricting portion to restrict the movement of the fixing belt in the direction of the rotation axis, the outer circumferential surface of the retaining member has a stepped portion along the circumferential direction of the fixing belt, the inner circumferential surface of the fixing belt has a heat-resistant member, and a sliding member is further provided on the heat-resistant member, the restricting portion is composed of the stepped portion, the restricted portion is composed of the heat-resistant member and the sliding member, and at least a part of the side surface of the sliding member faces the stepped portion Furthermore, the distance between the top surface of the sliding member opposite to the fixing belt and the bottom surface of the holding member adjacent to the stepped portion and facing the sliding member is smaller than the distance between the inner circumferential surface of the fixing belt and the outer circumferential surface of the holding member. It is characterized by the following.

[0012] ( 2 ) Image forming apparatus The image forming apparatus according to the present invention is characterized by comprising the fixing apparatus according to the present invention. [Effects of the Invention]

[0013] According to the present invention, it is possible to give heat resistance to the regulated part and suppress wear of the regulated part and / or the regulating part.

Brief Description of the Drawings

[0014] [Figure 1] It is a cross-sectional view showing a schematic configuration of an image forming apparatus according to an embodiment of the present invention. [Figure 2A] It is a perspective view of a fixing device in the image forming apparatus shown in FIG. 1. [Figure 2B] It is a cross-sectional view taken along line A-A shown in FIG. 2A. [Figure 3A] It is a perspective view of one end portion in the rotational axis direction of the fixing belt of the fixing device shown in FIGS. 1 to 2B viewed from the front side. [Figure 3B] It is a perspective view of the other end portion in the rotational axis direction of the fixing belt of the fixing device shown in FIGS. 1 to 2B viewed from the back side. [Figure 4] It is a perspective view of the state where the fixing belt is supported by one holding member and the other holding member viewed from the front side. [Figure 5A] It is a perspective view of an example of one holding member in the fixing device viewed from the front side. [Figure 5B] It is a perspective view of an example of the other holding member in the fixing device viewed from the front side. [Figure 6A] It is a cross-sectional view schematically showing a regulated part and a regulating part in the fixing device. [Figure 6B] It is a perspective cross-sectional view schematically showing a regulated part and a regulating part in the fixing device. [Figure 7A] It is a cross-sectional view schematically showing a regulated part and a regulating part in a fixing device according to the second embodiment - 1. [Figure 7B] It is a perspective cross-sectional view schematically showing a regulated part and a regulating part in a fixing device according to the second embodiment - 1. [Figure 8A] It is a cross-sectional view schematically showing a regulated part and a regulating part in a fixing device according to the second embodiment - 2. [Figure 8B] It is a perspective cross-sectional view schematically showing a regulated part and a regulating part in a fixing device according to Second Embodiment-2. [Figure 9A] It is a perspective view of one holding member in a fixing device according to Third Embodiment as viewed from the front side. [Figure 9B] It is a perspective view of the other holding member in a fixing device according to Third Embodiment as viewed from the front side. [Figure 10A] It is a perspective cross-sectional view schematically showing a regulated part and a regulating part in a fixing device according to Third Embodiment corresponding to First Embodiment. [Figure 10B] It is a perspective cross-sectional view schematically showing a regulated part and a regulating part in a fixing device according to Third Embodiment corresponding to Second Embodiment-1. [Figure 10C] It is a perspective cross-sectional view schematically showing a regulated part and a regulating part in a fixing device according to Third Embodiment corresponding to Second Embodiment-2. [Figure 11A] It is a perspective view of another example of one holding member as viewed from the right side on the front side. [Figure 11B] It is a perspective view of another example of the other holding member as viewed from the right side on the front side.

Embodiments for Carrying Out the Invention

[0015] Hereinafter, embodiments according to the present invention will be described with reference to the drawings. In the following description, the same parts are denoted by the same reference numerals. Their names and functions are also the same. Therefore, detailed descriptions thereof will not be repeated.

[0016] [Image Forming Apparatus] FIG. 1 is a cross-sectional view showing a schematic configuration of an image forming apparatus 100 according to an embodiment of the present invention.

[0017] As shown in Figure 1, the image forming apparatus 100 is a multifunction device having copying, scanning, facsimile, and printing functions, and transmits the image of the original document G read by the image reading device 102 to an external source. The image forming apparatus 100 also forms an image on a recording medium such as paper, either in color or monochrome, from the image of the original document G read by the image reading device 102 or from an external source. The image forming apparatus 100 may be a monochrome image forming apparatus. The image forming apparatus 100 may also be a color image forming apparatus of another form.

[0018] Above the image reading unit 130, a document feeder 160 (automatic document transport device) is provided, which is supported so as to be openable and closable relative to the image reading unit 130. The image reading unit 102 reads the document G transported by the document feeder 160. The document feeder 160 includes a document tray 161 on which the document G is placed, and a document output tray 162 on which the discharged document G is stacked. The document feeder 160 transports one or more documents G placed on the document tray 161 one by one onto the document reading unit 130b in the image reading unit 130, and discharges them into the document output tray 162. The image reading unit 130 is also provided with a document tray 130a on which the document G is placed. The image reading unit 102 reads the document G placed on the document tray 130a. When the document feeder 160 of the image forming apparatus 100 is opened, the document placement table 130a above the image reading unit 130 is opened, allowing the document G to be placed manually. The image reading unit 130 reads the document G being transported by the document feeder 160 with the scanning optical system 130c positioned at the reading position below the document reading unit 130b, or scans the scanning optical system 130c to read the document G placed on the document placement table 130a and generates image data.

[0019] The image forming apparatus main unit 101 includes a light scanning device 1, a developing device 2, a photoreceptor drum 3, a drum cleaning device 4, a charger 5, an intermediate transfer belt device 70, a secondary transfer device 11, a fixing device 12, a sheet transport path S, a paper feed cassette 18, and a sheet discharge tray 141.

[0020] The 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 (for example, black). The image forming unit 50 of the image forming apparatus 100 includes a developing device 2 for forming four types of toner images, a photoreceptor drum 3, a drum cleaning device 4, and Four chargers 5 are provided, each corresponding to black, cyan, magenta, and yellow, forming four image stations Pa, Pb, Pc, and Pd.

[0021] The charger 5 uniformly charges the surface of the photoreceptor drum 3 to a predetermined potential. The light scanning device 1 exposes the surface of the photoreceptor drum 3 to form an electrostatic latent image. The developing device 2 develops the electrostatic latent image on the surface of the photoreceptor drum 3 to form a toner image on the surface of the photoreceptor drum 3. The drum cleaning device 4 removes and recovers residual toner from the surface of the photoreceptor drum 3. Through the above series of operations, toner images of each color are formed on the surface of each photoreceptor drum 3.

[0022] The intermediate transfer belt device 70 includes intermediate transfer rollers 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 to form four different toner images corresponding to each color. The intermediate transfer rollers 6 transfer the toner images of each color formed on the surface of the photoreceptor drum 3 to the intermediate transfer belt 71, which moves in a circular motion direction C.

[0023] The intermediate transfer belt 71 is stretched over the intermediate transfer drive roller 72 and the intermediate transfer driven roller 73. In the image forming apparatus 100, the toner images of each color formed on the surface of each photoreceptor drum 3 are sequentially transferred and superimposed onto the surface of the intermediate transfer belt 71 to form a color toner image on the surface of the intermediate transfer belt 71.

[0024] The secondary transfer device 11 has a transfer nip section TN between the secondary transfer roller 11a and the intermediate transfer belt 71, and transports the sheet P that has been transported through the sheet transport path S by sandwiching it in the transfer nip section TN. When the sheet P passes through the transfer nip section TN, the toner image on the surface of the intermediate transfer belt 71 is transferred by the secondary transfer device 11 and the sheet P is transported to the fixing device 12. The cleaning device 9 removes and recovers waste toner that remains on the surface of the intermediate transfer belt 71 without being transferred to the sheet P.

[0025] The fixing device 12 includes a fixing belt 31 and a pressure roller 32 that rotate with the sheet P in between. The fixing device 12 heats and pressurizes the sheet P, on which the toner image has been transferred, between the fixing belt 31 and the pressure roller 32, thereby fixing the toner image to the sheet P. Although not shown in Figure 1, the fixing device 12 has components other than the fixing belt 31 and the pressure roller 32. Details of the fixing device 12 will be described later.

[0026] The paper feed cassette 18 is a cassette for storing sheets P used for image formation and is located on the lower side of the optical scanning device 1. The sheets P are pulled out of the paper feed cassette 18 by the pickup roller 16 and transported to the sheet transport path S. The sheets P transported to the sheet transport path S pass through the secondary transfer device 11 and the fixing device 12, are transported to the discharge roller 17, and discharged to the sheet discharge tray 141 in the discharge section 140. The sheet transport path S is equipped with a transport roller 13, a registration roller 14, and a discharge roller 17. The transport roller 13 facilitates the transport of the sheets P. The registration roller 14 temporarily stops the sheets P and aligns the leading edge of the sheets P. The registration roller 14 then transports the temporarily stopped sheets P in accordance with the timing of the toner image on the intermediate transfer belt 71.

[0027] Although Figure 1 shows only one paper feed cassette 18, the system is not limited to this configuration. Multiple paper feed cassettes 18 may be provided, each loaded with a different type of sheet P.

[0028] Furthermore, if the image forming apparatus 100 is to perform image formation not only on the front surface but also on the back surface of the sheet P, it transports the sheet P in the reverse direction from the discharge roller 17 to the sheet reversal path Sr. The image forming apparatus 100 reverses the front and back surfaces of the sheet P that has been transported in the reverse direction and guides it back to the register roller 14. The image forming apparatus 100 then forms an image on the back surface of the sheet P guided to the register roller 14 in the same way as the front surface, and transports it to the sheet discharge tray 141.

[0029] [Fusing device] Figure 2A is a perspective view of the fixing device 12 in the image forming apparatus 100 shown in Figure 1. Figure 2B is a cross-sectional view along line AA shown in Figure 2A.

[0030] The fixing device 12 further includes a support member 33 located inside the fixing belt 31, a fixing pad 34, a sliding sheet 35, a heat source 36, a reflector 37, a temperature sensing unit 38 (a thermopile in this example), a release plate 39, and a thermostat 40.

[0031] The fixing belt 31 is an endless, flexible belt, formed in a belt shape. The fixing belt 31 is rotatable around a rotation axis α that is perpendicular to the conveying direction H of the sheet P.

[0032] The fixing belt 31 is made by forming an elastic layer (e.g., a silicone rubber layer) of a predetermined thickness (e.g., 100 μm to 300 μm) on a metal substrate such as nickel or polyimide (PI) of a predetermined thickness (e.g., about 30 μm to 100 μm), and further forming a release layer (e.g., a fluororesin layer) of a thickness (e.g., about 20 μm to 30 μm) on top of that. Specifically, examples include a PFA tube provided on the silicone rubber upper layer, or a fluororesin coating. In this example, the fixing belt 31 is made of a nickel substrate with a thickness of 40 μm, with silicone rubber provided on top, and a PFA tube provided on the silicone rubber upper layer, resulting in an overall thickness of 300 μm. The inner diameter of the fixing belt 31 is not limited to this, but in this example it is set to 30 mm.

[0033] The fixing pad 34 is made of, for example, resin, and is formed in the shape of a long plate extending along the direction of the rotation axis α of the fixing belt 31 (rotation axis direction W). A sliding sheet 35 is provided between the fixing pad 34 and the fixing belt 31.

[0034] The support member 33 is a member that supports the fixing pad 34 while pressing the sliding sheet 35 against the inner circumferential surface of the fixing belt 31. Both ends of the support member 33 in the direction of the rotation axis W are fixed to the fixing frame (not shown). A reflector 37 is provided on the side of the support member 33 facing the heat source 36.

[0035] The heat source 36 is a component for heating the fixing belt 31 and extends along the rotation axis direction W of the fixing belt 31. The heat source 36 can be, for example, a lamp heater such as a halogen lamp. The fixing belt 31 is heated by the heat source 36 to a predetermined fixing temperature (for example, 160°C to 250°C, 160°C in this example). Therefore, not only the fixing belt 31 but also the sliding sheet 35 and the like have heat resistance to the above temperature.

[0036] The pressure roller 32 is positioned opposite the fixing pad 34, with the fixing belt 31 in between. The pressure roller 32 rotates around a rotation axis parallel to the rotation axis α of the fixing belt 31 and extends parallel to the fixing belt 31. The pressure roller 32 presses the fixing belt 31 toward the fixing pad 34 (sliding sheet 35), thereby forming a fixing nip portion FN between itself and the fixing belt 31. Specifically, the pressure roller 32 can be composed of a roller member in which the surface of a cylindrical core material made of a metal such as aluminum is covered with an elastic material such as rubber.

[0037] The pressure roller 32 receives driving force from a drive source (not shown), such as a motor, via gears (not shown). The pressure roller 32 is rotationally driven by the driving force from the drive source. The fixing belt 31 rotates in the first rotation direction R1, which is opposite to the second rotation direction R2 of the pressure roller 32, as the pressure roller 32 rotates. In other words, the pressure roller 32 forms a fixing nip portion FN by contacting the outer circumferential surface of the fixing belt 31, and transmits driving force to the fixing belt 31 via the fixing nip portion FN, thereby causing the fixing belt 31 to rotate in a driven manner.

[0038] The temperature sensing unit 38 detects the surface temperature of the fixing belt 31. In the fixing device 12, the temperature of the heat source 36 is controlled based on the temperature detected by the temperature sensing unit 38 so that the fixing belt 31 reaches the fixing temperature (160°C in this example).

[0039] The release plate 39 is positioned downstream of the fixing nip portion FN in the conveying direction H of the sheet P, and prevents the sheet P from wrapping around the fixing belt 31.

[0040] The thermostat 40 cuts off the power supply to the heat source 36 when the heat source 36 overheats. Specifically, the thermostat 40 is electrically connected to the power line (not shown) that supplies power to the heat source 36, and is designed to directly cut off the power supply to the heat source 36.

[0041] The temperature sensing unit 38 is fixed to the image forming apparatus body 101 (main frame) (see Figure 1). The temperature sensing unit 38 detects the surface temperature of the fixing belt 31 non-contact. The thermostat 40 is fixed to the fixing device body 12a (main frame). When the thermostat 40 reaches a predetermined reaction temperature (operating temperature, rated temperature), it activates and cuts off the power supply to the heat source 36.

[0042] Figures 3A and 3B are perspective views of the end portions of one side W1 and the other side W2 of the fixing belt 31 of the fixing device 12 shown in Figures 1 to 2B, viewed from the front and rear, respectively, in the direction of the rotation axis W. Figure 4 is a perspective view from the front showing how the fixing belt 31 is supported by one holding member 41a(41) and the other holding member 41b(41). Figures 5A and 5B are perspective views from the front showing an example of one holding member 41a(41) and an example of the other holding member 41b(41) in the fixing device 12, respectively. Figure 6A is a schematic cross-sectional view showing the restricted portion 42 and the restricting portion 43 in the fixing device 12. Figure 6B is a schematic perspective cross-sectional view showing the restricted portion 42 and the restricting portion 43 in the fixing device 12.

[0043] As shown in Figures 3A to 5B, the fixing device 12 comprises a holding member 41 and a fixing belt 31 (see Figures 3A and 3B) that is rotatably mounted on the outer circumferential surface 411 of the holding member 41 around a rotation axis α (see Figure 2B). The holding member 41 is fixed to the fixing device body 12a (body frame) (see Figure 2B).

[0044] In this example, the retaining member 41 is a pair of retaining members 41a and 41b, which hold both ends of the inner circumferential surface 311 of the fixing belt 31 in the direction of the rotation axis W. Of the pair of retaining members 41a and 41b, one retaining member 41a holds one side W1 (front side, operating side) of the inner circumferential surface 311 of the fixing belt 31 in the direction of the rotation axis W. edge The other holding member 41b holds the part, and the other holding member 41b is on the other side W2 (rear side) in the rotation axis direction W of the inner circumferential surface 311 of the fixing belt 31 edge It holds the department.

[0045] As shown in Figures 5A and 5B, one retaining member 41a and the other retaining member 41b each have a retaining portion 41a1, 41b1 and a protruding portion 41a2, 41b2 connected to the retaining portions 41a1, 41b1. The retaining portions 41a1, 41b1 hold the inner circumferential surface 311 of the fixing belt 31 on their outer circumferential surfaces 411. The retaining portions 41a1, 41b1 are arc-shaped portions with a part of the circumferential radius cut out. Examples of the shape of the retaining portions 41a1, 41b1 include arc shapes of 180 degrees or more, more preferably arc shapes of 270 degrees or more, and in this example, they are arc shapes of about 270 degrees. The protrusions 41a2 and 41b2 extend outward in the direction of the rotation axis W from the outer ends of the holding portions 41a1 and 41b1 in the direction of the rotation axis W, and protrude radially outward from the outer peripheral surface 411 of the holding portions 41a1 and 41b1. The protrusions 41a2 and 41b2 have wall surfaces 41a3 and 41b3 facing the end surface 31a of the fixing belt 31 (see Figure 6B).

[0046] The material for the retaining member 41 (41a, 41b) can be a heat-resistant resin material [for example, liquid crystal polymer (LCP) can be used.]

[0047] At least one (either one or both) of the pair of retaining members 41a, 41b (in this example, one retaining member 41a) has a stepped portion 43a (in this example, the side surfaces 43a1, 43a1 of the recesses extending in the circumferential direction R) along the circumferential direction R of the fixing belt 31 (see Figures 5A and 6A). As shown in Figures 6A and 6B, the inner circumferential surface 311 of the fixing belt 31 has a restricted portion 42 facing at least one (either one or both) of the pair of retaining members 41a, 41b (in this example, one retaining member 41a).

[0048] The fixing device 12 restricts the movement of the fixing belt 31 in the direction of the rotation axis W by the restricted portion 42 (sliding member 42b in this example) coming into contact with the restricting portion 43.

[0049] (First Embodiment) As shown in Figures 6A and 6B, a heat-resistant member 42a is provided on the inner circumferential surface 311 of the fixing belt 31, and a sliding member 42b is further provided on the heat-resistant member 42a. The restricting portion 43 is composed of a stepped portion 43a. The restricted portion 42 is composed of the heat-resistant member 42a and the sliding member 42b. At least a part (all or part) of the side surfaces 42b1, 42b1 of the sliding member 42b faces the stepped portion 43a (side surfaces 43a1, 43a1). In this example, the fixing belt 31 and the heat-resistant member 42a are bonded to each other with a heat-resistant adhesive, and the heat-resistant member 42a and the sliding member 42b are bonded to each other with a heat-resistant adhesive.

[0050] According to the fixing device 12 of the first embodiment, even if the fixing belt 31 moves in the direction of the rotation axis W when it rotates around the rotation axis α, the restricted portion 42 provided on the inner circumferential surface 311 of the fixing belt 31 comes into contact with the restricting portion 43 provided on the outer circumferential surface 411 of the holding member 41, thereby restricting the movement of the fixing belt 31 in the direction of the rotation axis W. The heat-resistant member 42a constituting the restricted portion 42 is provided on the inner circumferential surface 311 of the fixing belt 31. Therefore, the restricted portion 42 can be made heat-resistant. In addition, at least a part of the side surfaces 42b1, 42b1 of the sliding member 42b provided on the heat-resistant member 42a and constituting the restricted portion 42 faces the stepped portion 43a (side surfaces 43a1, 43a1) constituting the restricting portion 43. Therefore, when the fixing belt 31 rotates around the rotation axis α, even if at least a portion of the side surfaces 42b1, 42b1 of the sliding member 42b (restricted portion 42) comes into contact with the side surfaces 43a1, 43a1 of the stepped portion 43a (restricted portion 43), the sliding properties (wear resistance) of the sliding member 42b can suppress wear of the sliding member 42b (restricted portion 42) and / or the stepped portion 43a (restricted portion 43).

[0051] Here, as the heat-resistant member, for example, a heat-resistant resin member with a glass transition temperature of 80 degrees or higher can be used, but is not limited thereto. Examples of heat-resistant resin members include polyphenylene sulfide (PPS), polyether ether ketone (PEEK), and liquid crystal polymer (LCP). Furthermore, as the sliding member, for example, a sliding resin member with a coefficient of friction (dynamic friction coefficient) of 0.1 or less can be used, but is not limited thereto. Examples of sliding resin members include fluororesins such as polytetrafluoroethylene (PTFE). These points also apply to the second and third embodiments described later.

[0052] Incidentally, the sliding properties of the heat-resistant member 42a are less than those of the sliding member 42b. Therefore, when the fixing belt 31 rotates around the rotation axis α, if the heat-resistant member 42a comes into contact with the holding member 41, the heat-resistant member 42a and / or the holding member 41 are easily damaged by friction. For this reason, it is preferable to prevent the heat-resistant member 42a from coming into contact with the holding member 41.

[0053] In this embodiment, the width d1 of the sliding member 42b in the direction of the rotation axis W (see Figure 6A) (5.00 mm in this example) is greater than the width d2 of the heat-resistant member 42a in the direction of the rotation axis W (see Figure 6A) (for example, 4.00 mm or more and less than 5.00 mm, 4.00 mm in this example). Both ends of the sliding member 42b in the direction of the rotation axis W protrude more than both ends of the heat-resistant member 42a in the direction of the rotation axis W. Specifically, the protrusion amounts d3, d3 (see Figure 6A) of the sliding member 42b from the heat-resistant member 42a on both sides are set to predetermined protrusion amounts (0.50 mm, 0.50 mm in this example). Furthermore, the gaps d4, d4 on both sides between the side surfaces 42b1, 42b1 of the sliding member 42b and the stepped portion 43a (side surfaces 43a1, 43a1) (see Figure 6A) (0.50 mm, 0.50 mm in this example) are smaller than the gaps d5, d5 on both sides between the end faces 31a, 31a of the fixing belt 31 and the wall surfaces 41a3, 41b3 of the pair of holding members 41a, 41b (see Figure 6B, where only one side is shown). In other words, the gaps d4, d4 and d5, d5 on both sides are such that even if the side surfaces 42b1, 42b1 of the sliding member 42b come into contact with the stepped portion 43a (side surfaces 43a1, 43a1), the end faces 31a, 31a of the fixing belt 31 do not come into contact with the wall surfaces 41a3, 41b3 of the pair of holding members 41a, 41b. In the illustrated example, the anchoring belt 31 is positioned at a predetermined location (center) in the direction of the rotation axis W, and at this time, the gaps d4, d4 on both sides are equal, and the gaps d5, d5 on both sides are equal.

[0054] In this way, even when the fixing belt 31 moves in the direction of the rotation axis W as it rotates around the rotation axis α, the sliding member 42b can be brought into contact with the holding member 41, and thus, contact of the heat-resistant member 42a with the holding member 41 can be effectively prevented. This makes it possible to suppress friction-induced damage to the heat-resistant member 42a and / or the holding member 41.

[0055] However, since the fixing belt 31 becomes hot, if the fixing belt 31 comes into contact with the holding member 41 when it rotates around the rotation axis α, the holding member 41 is easily damaged by heat. For this reason, it is preferable to prevent the fixing belt 31 from coming into contact with the holding member 41.

[0056] In this respect, in this embodiment, the distance d6 (see Figure 6A) (0.25 mm in this example) between the top surface 42b2 of the sliding member 42b on the side opposite to the fixing belt 31 and the bottom surface 41c of the holding member 41 adjacent to the stepped portion 43a and facing the sliding member 43b is smaller than the distance d7 (see Figure 6A) (2.50 mm in this example) between the inner circumferential surface 311 of the fixing belt 31 and the outer circumferential surface 411 of the holding member 41.

[0057] This effectively prevents the fixing belt 31 from contacting the holding member 41, even when it moves in the direction of the rotation axis W as it rotates around the rotation axis α. This suppresses thermal damage to the holding member 41.

[0058] In this embodiment, the outer peripheral surface 411 of the retaining member 41 is provided with a recess extending in the circumferential direction R. The recess allows the restricted portion 42 to pass through and permits movement of the restricted portion 42 in the circumferential direction R. The stepped portion 43a is composed of two locations on both sides 43a1, 43a1 of the recess in the direction of the rotation axis W. That is, the recess is composed of the stepped portion 43a (sides 43a1, 43a1) and the bottom surface 41c of the retaining member 41. The recess (43a1, 43a1, 41c) can be provided on either one of the retaining members (in this example, one of the retaining members 41a) of the retaining member 41a and the other retaining member 41b in the direction of the rotation axis W.

[0059] Thus, even if the recesses (43a1, 43a1, 41c) are provided on either one of the retaining members (in this example, one retaining member 41a), when the fixing belt 31 rotates around the rotation axis α and moves in the direction of the rotation axis W, the side surfaces 43a1, 43a1 of the recesses (43a1, 43a1, 41c) on the retaining member 41 in the direction of the rotation axis W can restrict the movement of the fixing belt 31 on both sides W1 and W2 in the direction of the rotation axis W.

[0060] In the first embodiment, the stepped portion 43a is provided on one of the retaining members 41a(41), but it may also be provided on the other retaining member 41b(41). In this case, the restricted portion 42 is provided on the other side W2 in the direction of the rotation axis W of the inner circumferential surface 311 of the fixing belt 31.

[0061] (Second Embodiment) <Second Embodiment-1> Figure 7A is a schematic cross-sectional view showing the restricted portion 42 and the restricted portion 43 in the fixing device 12 according to the second embodiment-1. Figure 7B is a schematic perspective cross-sectional view showing the restricted portion 42 and the restricted portion 43 in the fixing device 12 according to the second embodiment-1.

[0062] The fixing device 12 according to the second embodiment-1 has the same configuration as the fixing device 12 according to the first embodiment, except that the restricted part 42 and the restricting part 43 are changed. Therefore, in the second embodiment-1, the same reference numerals are used for similar components in the first embodiment, and their descriptions are omitted.

[0063] A stepped portion 44 is provided on the outer circumferential surface 411 of the retaining member 41, along the circumferential direction of the fixing belt 31. Sliding members 43b, 43b are provided on the stepped portion 44 (side surfaces 44a, 44a). A heat-resistant member 42a is provided on the inner circumferential surface 311 of the fixing belt 31. The restricting portion 43 is composed of sliding members 43b, 43b. The restricted portion 42 is composed of a heat-resistant member 42a. The side surfaces 42a1, 42a1 of the heat-resistant member 42a face the side surfaces 43b1, 43b1 of the sliding member 43b. In this example, the stepped portion 44 and the sliding members 43b, 43b are bonded to each other with a heat-resistant adhesive.

[0064] According to the fixing device 12 of the second embodiment-1, even if the fixing belt 31 moves in the direction of the rotation axis W when it rotates around the rotation axis α, the restricted portion 42 provided on the inner circumferential surface 311 of the fixing belt 31 comes into contact with the restricting portion 43 provided on the outer circumferential surface 411 of the holding member 41, thereby restricting the movement of the fixing belt 31 in the direction of the rotation axis W. The heat-resistant member 42a constituting the restricted portion 42 is provided on the inner circumferential surface 311 of the fixing belt 31. Therefore, the restricted portion 42 can be made heat-resistant. In addition, the side surfaces 42a1, 42a1 of the heat-resistant member 42a constituting the restricted portion 42 face the side surfaces 43b1, 43b1 of the sliding member 43b provided on the stepped portion 44 (side surfaces 44a, 44a) and constituting the restricting portion 43. Therefore, when the fixing belt 31 rotates around the rotation axis α, even if the side surfaces 42a1, 42a1 of the heat-resistant member 42a (restricted portion 42) come into contact with the side surfaces 43b1, 43b1 of the sliding member 43b (restricted portion 43), the sliding properties (wear resistance) of the sliding member 43b can suppress wear of the heat-resistant member 42a (restricted portion 42) and / or the sliding member 43b (restricted portion 43).

[0065] In this embodiment, sliding members 43b, 43b, 43b are provided on both the stepped portion 44 (side surfaces 44a, 44a) and the bottom surface 41c of the holding member 41 that is adjacent to the stepped portion 44 and faces the heat-resistant member 42a.

[0066] However, since the fixing belt 31 becomes hot, when the fixing belt 31 rotates around the rotation axis α, if the fixing belt 31 comes into contact with the holding member 41 and the sliding member 43b, the holding member 41 and the sliding member 43b are easily damaged by heat. For this reason, it is preferable to prevent the fixing belt 31 from coming into contact with the holding member 41 and the sliding member 43b.

[0067] In this respect, in this embodiment, the distance d11 (see Figure 7A) (0.25 mm in this example) between the top surface 42a2 of the heat-resistant member 42a opposite to the fixing belt 31 and the sliding member 43b (bottom surface 43b2) provided on the bottom surface 41c of the holding member 41 is smaller than the distance d12 (see Figure 7A) (1.00 mm in this example) between the inner circumferential surface 311 of the fixing belt 31, the outer circumferential surface 411 of the holding member 41, and the top surfaces 43b3, 43b3 of the sliding members 43b, 43b provided on the stepped portion 44 (side surfaces 44a, 44a) that face the fixing belt 31. In this example, the outer circumferential surface 411 of the holding member 41 and the top surfaces 43b3, 43b3 of the sliding members 43b, 43b are flush.

[0068] By doing so, even when the fixing belt 31 moves in the direction of the rotation axis W as it rotates around the rotation axis α, contact between the fixing belt 31 and the holding member 41 and the sliding member 42b can be effectively prevented. This suppresses thermal damage to the holding member 41 and the sliding member 42b.

[0069] More specifically, the gaps d13, d13 (see Figure 7A) (0.50 mm, 0.50 mm in this example) on both sides between the sides 42a1, 42a1 of the heat-resistant member 42a (see Figure 7A) and the sides 43b1, 43b1 of the sliding member 43b are smaller than the gaps d5, d5 (see Figure 6B) on both sides between the end faces 31a, 31a of the fixing belt 31 and the wall faces 41a3, 41b3 of the pair of holding members 41a, 41b. In other words, the gaps d13, d13 and d5, d5 on both sides are such that even if the sides 42a1, 42a1 of the heat-resistant member 42a abut against the sides 43b1, 43b1 of the sliding member 43b, the end faces 31a, 31a of the fixing belt 31 do not come into contact with the wall faces 41a3, 41b3 of the pair of holding members 41a, 41b. In the illustrated example, the anchoring belt 31 is positioned in the center in the direction of the rotation axis W, and at this time, the gaps d13, d13 on both sides are equal, and the gaps d5, d5 on both sides are equal. The width d14 of the heat-resistant member 42a in the direction of the rotation axis W (see Figure 7A) is set to a predetermined distance (3.00 mm in this example). The thickness d15 of the heat-resistant member 42a in the radial direction V (see Figure 7A) is set to a predetermined distance (2.00 mm in this example). The width d14 and thickness d15 of the heat-resistant member 42a are set to values ​​that can maintain the desired strength and heat resistance. The thicknesses d16, d16, d16 of the sliding member 43b (see Figure 7A) are set to a predetermined distance (0.50 mm, 0.50 mm, 0.50 mm in this example). The thickness d16 of the sliding member 43b is set to a value that can maintain the desired strength.

[0070] <Second Embodiment-2> Figure 8A is a schematic cross-sectional view showing the restricted portion 42 and the restricted portion 43 in the fixing device 12 according to the second embodiment-2. Figure 8B is a schematic perspective cross-sectional view showing the restricted portion 42 and the restricted portion 43 in the fixing device 12 according to the second embodiment-2.

[0071] The fixing device 12 according to the second embodiment-2 is the fixing device 12 according to the second embodiment-1 in which the height of the sliding member 43b in the radial direction V is increased.

[0072] Incidentally, the sliding properties of the retaining member 41 are less than those of the sliding member 42b. Therefore, when the fixing belt 31 rotates around the rotation axis α, if the fixing belt 31 comes into contact with the retaining member 41, the fixing belt 31 and / or the retaining member 41 are easily damaged by friction. For this reason, it is preferable to prevent the fixing belt 31 from coming into contact with the retaining member 41.

[0073] In this respect, in this embodiment, the sliding member 43b protrudes from the outer peripheral surface 411 of the holding member 41 toward the fixing belt 31. The distance d11 (see Figure 8A) (1.00 mm in this example) between the top surface 42a2 of the heat-resistant member 42a opposite to the fixing belt 31 and the sliding member 43b provided on the bottom surface 41c of the holding member 41 adjacent to the stepped portion 44 and facing the heat-resistant member 42a is greater than the distance d121 (see Figure 8A) (0.25 mm in this example) between the inner peripheral surface 311 of the fixing belt 31 and the top surfaces 43b3, 43b3 of the sliding member 43b facing the fixing belt 31. More specifically, the amount d17 of the protrusion of the sliding member 43b from the outer peripheral surface 411 of the holding member 41 is greater than 0 mm and smaller than the distance d122 (see Figure 8A) between the inner peripheral surface 311 of the fixing belt 31 and the outer peripheral surface 411 of the holding member 41.

[0074] This effectively prevents the fixing belt 31 from contacting the holding member 41, even when it moves in the direction of the rotation axis W as it rotates around the rotation axis α. This suppresses friction-induced damage to the fixing belt 31 and / or the holding member 41.

[0075] (Third embodiment) Figures 9A and 9B are perspective views of one retaining member 41a(41) and the other retaining member 41b(41) in the fixing device 12 according to the third embodiment, viewed from the front. Figures 10A to 10C are schematic cross-sectional views showing the restricted portion 42 and the restricted portion 43 in the fixing device 12 according to the third embodiment, corresponding to the first embodiment, second embodiment-1, and second embodiment-2, respectively. Note that in Figures 10A to 10C, the end portions on both sides in the direction of the rotation axis W are shown in a single figure.

[0076] The fixing device 12 according to the third embodiment is the same as the fixing device 12 according to the first embodiment, second embodiment-1, and second embodiment-2, except that the stepped portion 43a is configured in two places. Therefore, in the third embodiment, the same reference numerals are used for the same components as in the first embodiment, second embodiment-1, and second embodiment-2, and their descriptions are omitted.

[0077] In this embodiment, both the one retaining member 41a(41) and the other retaining member 41b(41) are provided with a stepped portion 43a, where the outer side is lower and the inner side is higher in the direction of the rotation axis W. When stepped portions 43a, 43a are provided on both the one retaining member 41a(41) and the other retaining member 41b(41) in this way, restricted portions 42, 42 can be provided on both sides of the fixing belt 31 in the direction of the rotation axis W.

[0078] (Common embodiment of the first to third embodiments) In this regard, in the first to third embodiments, the widths d1 and d14 of the restricted portion 42 in the direction of the rotation axis W are smaller than the insertion widths (d1+d4+d4) and (d14+d13+d13) of the restricted portion 42 into the restricting portion 43 in the direction of the rotation axis W.

[0079] By doing so, when the fixing belt 31 rotates around the rotation axis α and the fixing belt 31 contacts the holding member 41, the frequency of sliding contact between the restricted portion 42 and the restricting portion 43 can be suppressed. This makes it possible to suppress wear of the restricted portion 42 and / or the restricting portion 43.

[0080] In the first to third embodiments, the restricted portion 42 may be formed on the inner circumferential surface 311 of the anchoring belt 31 over its entire circumference. In other words, the restricted portion 42 is formed continuously (endlessly) along the circumferential direction R on the inner circumferential surface 311 of the anchoring belt 31.

[0081] In this way, the movement of the fixing belt 31 in the direction of the rotation axis W can be reliably restricted by the restricted portion 42.

[0082] In the first to third embodiments, the holding portions 41a1 and 41b1 of one holding member 41a(41) and the other holding member 41b(41) are arc-shaped portions with a part of the circumferential R cut out, but they may also be cylindrical portions.

[0083] Figures 11A and 11B are perspective views of other examples of one retaining member 41a(41) and another example of the other retaining member 41b(41), viewed from the right side of the front.

[0084] The holding portion 41a1 of one holding member 41a(41) shown in Figure 11A, and the holding portion 41b1 of the other holding member 41b(41) shown in Figure 11B, are cylindrical in shape.

[0085] In addition, while Figure 11A shows one of the retaining members 41a(41) as an example of the configuration of the first embodiment, second embodiment-1, and second embodiment-2, in the case of the first embodiment, second embodiment-1, and second embodiment-2, the other retaining member 41b(41) having the cylindrical retaining portion 41b1 may also have a configuration example like that of the first embodiment, second embodiment-1, and second embodiment-2. Furthermore, Figure 11B shows an example of the other retaining member 41b(41) as an example of the third embodiment, in which case the one retaining member 41a(41) having the cylindrical retaining portion 41a1 also has a configuration example like that of the third embodiment.

[0086] In the first to third embodiments, when the holding portions 41a1 and 41b1 of a pair of holding members 41a and 41b are arc-shaped portions with a part of the circumferential R cut out, it is preferable that the restricting portion 43 (stepped portion 43a, 44) is formed entirely on the outer circumferential surfaces 411, 411 of the holding portions 41a1 and 41b1. In other words, it is preferable that the restricting portion 43 (43a, 44) is formed continuously along the circumferential R between one end and the other end on the outer circumferential surface 411 of the holding portions 41a1 and 41b1.

[0087] In this way, the regulating unit 43 can reliably restrict the movement of the fixing belt 31 in the direction of the rotation axis W.

[0088] Furthermore, in the first to third embodiments, when the holding portions 41a1 and 41b1 of the pair of holding members 41a and 41b are cylindrical, it is preferable that the restricting portion 43 (stepped portion 43a and 44) ​​is formed on the outer peripheral surfaces 411 and 411 of the holding portions 41a1 and 41b1 over the entire circumference. In other words, it is preferable that the restricting portion 43 (43a and 44) ​​is formed continuously (endlessly) along the circumferential direction R on the outer peripheral surfaces 411 and 411 of the holding portions 41a1 and 41b1.

[0089] In this way, the regulating unit 43 can reliably restrict the movement of the fixing belt 31 in the direction of the rotation axis W.

[0090] Furthermore, the restricted portion 42 may be partially formed at one or more locations on the inner circumferential surface 311 of the fixing belt 31. And / or, the restricting portion 43 may be partially formed at one or more locations on the outer circumferential surfaces 411, 411 of the holding portions 41a1, 41b1. In addition, when the restricted portion 42 is partially formed at one or more locations and the restricting portion 43 is partially formed at one or more locations, and when the restricted portion 42 is partially formed at one or more locations and the holding portions 41a1, 41b1 are arc-shaped portions, a taper may be provided at the downstream end of the partially restricted portion 42 in the first rotation direction R1, and / or a taper may be provided at the upstream end of the partially restricted portion 43 in the first rotation direction R1.

[0091] The present invention is not limited to the embodiments described above and can be implemented in various other forms. Therefore, these embodiments are merely illustrative in all respects and should not be interpreted restrictively. The scope of the present invention is defined by the claims and is not restricted in any way by the text of the specification. Furthermore, any modifications or changes within the equivalent scope of the claims are all within the scope of the present invention. [Explanation of symbols]

[0092] 100 Image forming apparatus 12 Fixing device 12a Fixing device body 31 Fixing belt 311 Inner surface 31a End face 41 Retaining member 411 Outer surface 41a One retaining member 41a Retaining member 41a1 Holding part 41b Other retaining member 41b1 Holding part 41c base 42 Regulated part 42a Heat-resistant material 42a1 side 42b Sliding member 42b1 Side view 43 Regulatory Department 43a Stepped section 43a1 Side view 43b Sliding member 43b1 Side 44 Stepped section 44a Side view R circumferential direction V radial direction W rotation axis direction W1 One side W2 opposite side α rotation axis

Claims

1. A fixing device comprising a holding member fixed to the fixing device body, and a fixing belt rotatably mounted on the outer surface of the holding member around a rotation axis, A restricting portion is provided on the outer circumferential surface of the retaining member, facing the fixing belt, and a restricted portion is provided on the inner circumferential surface of the fixing belt, facing the retaining member, and the movement of the fixing belt in the direction of the rotation axis is restricted by the restricted portion contacting the restricting portion. The outer circumferential surface of the retaining member is provided with a stepped portion that is aligned with the circumferential direction of the fixing belt. A heat-resistant member is provided on the inner circumferential surface of the fixing belt, and a sliding member is further provided on the heat-resistant member. The regulating portion is composed of the stepped portion, The restricted portion is composed of the heat-resistant member and the sliding member, At least a portion of the side surface of the sliding member faces the stepped portion, An anchoring device characterized in that the distance between the top surface of the sliding member opposite to the anchoring belt and the bottom surface of the holding member adjacent to the stepped portion and facing the sliding member is smaller than the distance between the inner circumferential surface of the anchoring belt and the outer circumferential surface of the holding member.

2. A fixing device according to claim 1, A fixing device characterized in that the width of the sliding member in the direction of the rotation axis is greater than the width of the heat-resistant member in the direction of the rotation axis, and both ends of the sliding member in the direction of the rotation axis protrude more than both ends of the heat-resistant member in the direction of the rotation axis.

3. A fixing device according to claim 1 or claim 2, The outer circumferential surface of the retaining member is provided with a recess extending in the circumferential direction. The fixing device is characterized in that the stepped portion is composed of two locations on both sides of the recess in the direction of the rotation axis.

4. A fixing device according to claim 1 or claim 2, A fixing device characterized in that the width of the restricted portion in the direction of the rotation axis is smaller than the insertion width of the restricted portion into the restricting portion in the direction of the rotation axis.

5. A fixing device according to claim 1 or claim 2, The fixing device is characterized in that the restricted portion is formed over the entire circumference of the inner surface of the fixing belt.

6. A fixing device according to claim 1 or claim 2, The retaining member has a retaining portion on its outer surface that holds the inner surface of the fixing belt, The holding portion is an arc-shaped portion, The fixing device is characterized in that the restricting portion is formed over the entire outer surface of the holding portion.

7. A fixing device according to claim 1 or claim 2, The retaining member has a retaining portion on its outer surface that holds the inner surface of the fixing belt, The holding portion is a cylindrical portion with a cylindrical shape, The fixing device is characterized in that the restricting portion is formed over the entire circumference of the outer surface of the holding portion.

8. An image forming apparatus characterized by comprising a fixing device according to claim 1 or claim 2.

Images