Method for manufacturing heat-resistant component, fixing device, and image forming apparatus

Abstract

To provide a resistance heating component that reduces start-up time without increasing heat capacity, and easily constructs a fixing device that has a wide fixing area and is designed for high-speed productivity.SOLUTION: A resistance heating component 1 is in contact with a fixing belt 11 formed of heat resistant material to heat the fixing belt and is provided at a part separated from a fixing area m where a recording material 16 is sandwiched and conveyed between the fixing belt 11 and fixing area forming means, and comprises a metal substrate 2 that has a small heat capacity and a resistance heating layer 3 that is laminated on a front face or a rear face of the substrate 2 with an insulating layer 4 therebetween. A fixing device heats the fixing belt 11 with the resistance heating component 1, and an image forming apparatus includes the fixing device.SELECTED DRAWING: Figure 1

Description

Technical Field

[0001] The present invention relates to a resistive heating component of manufacturing method and a fixing device, and an image forming apparatus.

Background Art

[0002] As a conventional fixing device, for example, the one described in Patent Document 1 is already known. Patent Document 1 discloses a fixing device having a heating body that is fixedly supported, a film that slides on the heating body, and a pressing means that presses a recording material against the film. The heating body has a heat generating layer provided on a substrate, an electrode that energizes the heat generating layer, and a heat fusible portion provided on the substrate that melts at a predetermined temperature and blocks the energization to the heat generating layer.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] The technical problem to be solved by the present invention is to provide a resistive heating component that can easily construct a fixing device capable of shortening the start-up time without increasing the heat capacity and expanding the fixing area to achieve high-speed productivity.

Means for Solving the Problems

[0005] The invention according to claim 1 includes a fixing belt made of a heat-resistant material that circulates and moves, a fixing area forming means for fixing an unfixed image of the recording material in a fixing area where the recording material is sandwiched and conveyed between the fixing belt, and a resistive heating component that contacts and heats the fixing belt at a portion away from the fixing area of the fixing belt. The resistive heating component includes a metal base material and a resistive heating layer laminated on the front or back surface of the base material via an insulating layer. The resistive heating component is disposed in contact with the back surface of the fixing belt. The distance L1 from the contact center position of the resistive heating component with the fixing belt to the center position of the fixing area in the circulation movement direction of the fixing belt is longer than the distance L2 from the center position of the fixing area to the contact center position in the circulation movement direction of the fixing belt. It is a fixing device characterized by the above.

[0006] The invention according to claim 2 is a fixing device according to claim 1, wherein the resistive heating component includes a roll made of a metal cylindrical body as the base material, a resistive heating layer laminated on the surface of the base material via an insulating layer, a protective layer that covers the resistive heating layer and contacts the back surface of the fixing belt, and an electrode that contacts the surface in the thickness direction of the resistive heating layer not covered by the protective layer and supplies electric power from a power supply for power supply to the resistive heating layer. Claim 3 The invention according to claim 7 is a fixing device, in the fixing device according to claim 1, characterized in that the base material is configured to have a thickness of 0.2 to 1.0 mm. Claim 4 The invention according to claim 11 is a fixing device, in the fixing device according to claim 1, characterized in that the insulating layer is made of any one of polyimide (PI), polyamideimide (PAI), diallyl phthalate (PDAP), and polyetheretherketone (PEEK). The invention according to claim 5 is a fixing device according to claim 1, wherein the resistive heating component functions as a tensioning roll for tensioning the fixing belt. The invention according to claim 6 is a fixing device according to claim 1, wherein the resistive heating component functions as a tensioning roll for tensioning the fixing belt and also functions as a driving roll for driving the fixing belt. The invention according to claim 7 is a fixing device according to any one of claims 1 to 6, wherein the fixing area forming means includes an auxiliary heating element that suppresses heat loss when the fixing belt heated by the resistive heating component passes through the fixing area.

[0007] Claim 8 The invention according to claim 23 is a resistance heating component provided at a position away from a fixing area that heats in contact with a fixing belt made of a heat-resistant material and sandwiches and conveys a recording material between the fixing belt. The resistance heating component includes a metal roll made of a cylindrical body as a metal base material, and a resistance heating layer laminated on the outer surface or the inner surface of the metal roll via an insulating layer. When manufacturing the resistance heating component, a layer forming step of sequentially forming a laminate including an insulating layer and a resistance heating layer on the outer peripheral portion or the inner peripheral portion of the metal roll is provided. Among the layer forming steps, at least the insulating layer forming step positions the metal roll and uses a mold that defines a cavity corresponding to the thickness of the layer to be formed between the outer peripheral portion or the inner peripheral portion of the metal roll, and pours the coating material of the layer to be formed into the cavity and bakes it to apply the layer to be formed. The manufacturing method of the resistance heating component is characterized by adopting a mold pouring coating method.

[0008] Claim 9 The invention according to claim 29 is a manufacturing method of a resistance heating component according to claim 8 31, characterized in that the metal roll is high-tensile steel and the coating material of the insulating layer uses polyimide. Claim 10 The invention according to claim 35 is according to claim 9In the method for manufacturing a resistive heating component according to the present invention, the cylindricity of the outer peripheral surface of the insulating layer is closer to a cylinder than the cylindricity of the metal roll, which is a method for manufacturing a resistive heating component. Claim 11 The invention according to claim 8 In the method for manufacturing a resistive heating component according to claim

[0011] The invention according to claim 12 is an image forming apparatus comprising an image forming means for forming an image on a recording material and a fixing device according to any one of claims 1 to 7 for fixing the unfixed image formed by the image forming means.

Effect of the Invention

[0012] According to the invention of claim 1, it is possible to easily construct a fixing device capable of coping with high-speed productivity with a short start-up time without increasing the heat capacity and with a wide fixing area. In particular, by devising the layout of the resistive heating component with respect to the fixing belt, the front surface side of the fixing belt can be sufficiently heated until it reaches the fixing area of the fixing belt. According to the invention according to claim 2, Even if the base material is made thin, it is possible to ensure the strength against the tension of the fixing belt and the load application in the fixing area, and there is no concern of breakage even if a temperature difference occurs due to the resistive heating layer. Further, since the structure between the electrode and the metal base material is a two-layer structure of the resistive heating layer and the insulating layer, even if the electrode wears, it is possible to provide a structure in which the member pressing the electrode and the metal base material are less likely to be short-circuited. Furthermore, compared with the case where a resistive heating layer is provided on the back surface of the base material, heat conduction to the fixing belt can be efficiently performed. Also, even if a resistive heating layer is provided on the surface of the base material, it is possible to avoid direct rubbing between the fixing belt and the resistive heating layer, and power can be appropriately supplied to the resistive heating layer. Claim 3 According to the invention of claim In forming a roll made of a cylinder as a metal base material with high-tensile steel, the base material can be made thin with a thickness of 0.2 to 1.0 mm. 4According to the invention according to claim, when laminating a resistance heating layer on a base material via an insulating layer, the insulating layer can be easily selected. According to the invention according to claim 5, the fixing belt can be heated in a form that also serves as a tensioning roll of the fixing belt as the resistive heating component. According to the invention according to claim 6, the fixing belt can be heated in a form that also serves as a tensioning roll that functions as a driving roll of the fixing belt as the resistive heating component. According to the invention according to claim 7, compared with the case where the fixing area does not include an auxiliary heating element, it is possible to more effectively suppress heat loss when the fixing belt passes through the fixing area. Claim 8 According to the invention according to claim, a resistance heating component that can easily manufacture a fixing device capable of shortening the start-up time without increasing the heat capacity and widening the fixing area to achieve high-speed productivity can be easily manufactured. Claim 9 According to the invention according to claim, when using high-tensile steel as a metal roll, although the workability is poor, the surface characteristics of the insulating layer made of polyimide can be ensured to be good by the mold casting coating method, and the film thickness of the resistance heating layer can be easily made uniform. Claim 10 According to the invention according to claim, even if the workability of high-tensile steel is poor and the runout and cylindricity of the metal roll deteriorate, the influence of the runout and cylindricity of the metal roll can be mitigated at the stage of forming the insulating layer. Claim 11 According to the invention according to claim, even when forming the heating layer, a uniform film thickness can be easily ensured. 。 Claim 12 According to the invention according to claim, an image forming apparatus including a fixing device capable of shortening the start-up time without increasing the heat capacity and widening the fixing area to achieve high-speed productivity can be constructed.

Brief Description of the Drawings

[0013]

Figure 1

Figure 2

Figure 3

Figure 4

Figure 5

Figure 6

Figure 7

Figure 8

Embodiments for Carrying Out the Invention

[0014] ◎ Outline of the Embodiment Fig. 1(a) shows an outline of an embodiment of an image forming apparatus using a fixing device including a resistance heating component to which the present invention is applied. In the same figure, the image forming apparatus includes an image forming means 15 for forming an image on a recording material 16, and a fixing device 10 for fixing the unfixed image formed by the image forming means 15. Here, as the image forming means 15, any appropriate method such as an electrophotographic method or an ion stream writing method can be selected as long as it can form an unfixed image on the recording material 16. Further, the fixing device 10 includes a fixing belt 11 made of a heat-resistant material that circulates and moves, a fixing area forming means 12 for fixing the unfixed image of the recording material 16 in a fixing area m where the recording material 16 is sandwiched and conveyed between the fixing belt 11, a resistance heating component 1 that contacts and heats the fixing belt 11 at a portion away from the fixing area m of the fixing belt 11, and a tensioning member 13 for tensioning the fixing belt 11 between the fixing area forming means 12 and the resistance heating component 1.

[0015] Here, the fixing belt 11 widely includes those made of heat-resistant materials such as polyimide (PI) and polyetherimide (PEI). Further, as the fixing area forming means 12, it is only necessary to have a configuration for sandwiching and conveying the recording material 16 in the fixing area m of the fixing belt 11. Usually, a receiving member 12b is provided on the back surface side of the fixing belt 11, and a pressing member 12a is arranged on the front surface side of the fixing belt 11, and a fixing area m for sandwiching the fixing belt 11 and the recording material 16 between the pressing member 12a and the receiving member 12b is secured. In particular, in this example, since the resistance heating component 1 for heating the fixing belt 11 is provided at a portion away from the fixing area m of the fixing belt 11, the fixing area forming means 12 basically does not need to include a heating means, but it is of course possible to additionally provide a heating means. Thus, according to this example, compared with the case where a heating area is provided in the fixing area of the fixing belt 11, by functionally separating the heating area and the fixing area m for the fixing belt 11, it becomes possible to pass the fixing belt 11 that has been sufficiently heated in the fixing area m.

[0016] Also, in this embodiment, the resistance heating component 1 is applicable to those provided at a portion away from the fixing area m of the fixing belt 11 as shown in FIGS. 1(a) and 1(b). Made of metal It includes a base material 2 and a resistance heating layer 3 laminated on the front or back surface of the base material 2 via an insulating layer 4. The base material 2 may be made of metal, and its form is not limited to a roll shape and includes flat plate shapes. Also, the resistance heating layer 3 may be on either the front or back surface of the base material 2. However, considering shortening the rise time of the resistance heating layer 3 and energy saving, it is necessary to have a configuration in which an insulating layer 4 is interposed between the resistance heating layer 3 and the base material 2 so that the energization to the resistance heating layer 3 does not leak to the side of the metal base material 2.

[0017] Next, representative or preferred embodiments of the resistance heating component 1 according to this embodiment will be described. First, as a preferred embodiment of the base material 2, there is an embodiment in which it is a metal roll 2a made of a metal cylindrical body. In this example, the metal roll 2a is preferably made of high-tensile steel with a tensile strength of 490 MPa or higher, and the thickness of the metal roll 2a may be selected in consideration of rigidity and workability. Also, when using the metal roll 2a, the resistance heating layer 3 is laminated on the Outer surface metal roll 2a with an insulating layer 4 interposed therebetween. The mode of being is preferable. Furthermore, when the resistance heating layer 3 is formed on the surface of the base material 2, regardless of the form of the base material 2, in order to improve the wettability of the lubricant and the driving tack force with the fixing belt 11 on the resistance heating layer 3 of the base material 2, it is preferable to form the protective layer 5 with a material having low releasability (for example, polyimide or PEEK material). Furthermore, although the insulating layer 4 may be appropriately selected, it is preferably configured using a material having excellent surface properties in consideration of manufacturability. In particular, from the viewpoint of maintaining good surface properties of the resistance heating layer 3, the surface roughness of the insulating layer 4 is preferably smoother than the surface roughness of the base material 2.

[0018] Also, although the manufacturing method of the resistance heating component 1 may be appropriately selected, for example, when the metal roll 2a is made of high-tensile steel, the following manufacturing method is preferable. That is, it is a resistance heating component 1 provided at a position away from the fixing area m that heats in contact with the fixing belt 11 made of a heat-resistant material and sandwiches and conveys the recording material 16 between the fixing belt 11. Made of metalWhen manufacturing the resistive heating component 1 including a metal roll 2a in a form of a cylindrical body as a base material 2, and a resistive heating layer 3 laminated via an insulating layer 4 on the outer surface or the inner surface of the metal roll 2a, there is provided a layer forming step of sequentially forming a laminate including the insulating layer 4 and the resistive heating layer 3 on the outer peripheral portion or the inner peripheral portion of the metal roll 2a. Among each layer forming step, at least in the insulating layer forming step, as shown in FIG. 1(c), the metal roll 2a is positioned, and a mold 7 partitioning a cavity portion 7b corresponding to the thickness of the layer to be formed between the outer peripheral portion or the inner peripheral portion of the metal roll 2a is used, and a coating material M of the layer to be formed in the cavity portion 7b is poured from an injection port 7a communicating with the cavity portion 7b, and there is a method of adopting a mold pouring coating method of coating the layer to be formed by baking.

[0019] In such a manufacturing method, the metal roll 2a is high-tensile steel, and it is possible to use polyimide as the coating material M of the insulating layer 4. Furthermore, according to such a manufacturing method, since the cylindricity of the outer surface of the insulating layer 4 depends on the surface accuracy of the inner surface of the cavity portion 7b of the mold 7, it is possible to form the cylindricity of the outer peripheral surface of the insulating layer 4 to be closer to a cylinder than the cylindricity of the metal roll 2a. Furthermore, in the manufacturing method of this type of resistive heating component 1, when the resistive heating layer 3 is formed by using the mold pouring coating method also in the resistive heating layer forming step among each layer forming step, the surface of the resistive heating layer 3 can be formed smoothly in the same manner as the surface property of the insulating layer 4.

[0020] Next, a representative aspect or a preferable aspect of the fixing device according to the present embodiment will be described. First, as a representative aspect of the resistive heating component 1, there is an aspect of being disposed in contact with the back surface of the fixing belt 11. Furthermore, from the viewpoint of reducing the sliding resistance between the resistive heating component 1 and the fixing belt 11, it is preferable that the resistive heating component 1 functions as a stretching member for stretching the fixing belt 11. Furthermore, it is more preferable that the resistive heating component 1 functions as a stretching member for stretching the fixing belt 11 and also functions as a driving member for driving the fixing belt 11. In addition, in the mode of heating the back surface of the fixing belt 11 with the resistance heating component 1, since it takes time for the heat on the back surface to conduct to the surface of the fixing belt 11, the distance from the contact center position of the resistance heating component 1 with the fixing belt 11 to the center position of the fixing area m in the circulation movement direction of the fixing belt 11 is L1 (not shown in FIG. 1), and the distance from the center position of the fixing area m to the contact center position in the circulation movement direction of the fixing belt is L2 (not shown in FIG. 1). It is preferable to satisfy the relationship of L1 > L2. Furthermore, an auxiliary heating element for suppressing heat loss when the fixing belt 11 heated by the resistance heating component 1 passes through the fixing area m may be provided.

[0021] Hereinafter, the present invention will be described in more detail based on the embodiments shown in the accompanying drawings. ◎Embodiment 1 -Overall Configuration of Image Forming Apparatus- FIG. 2 is an explanatory diagram showing the overall configuration of the image forming apparatus according to Embodiment 1. In this figure, the image forming apparatus 20 is an image forming apparatus of an intermediate transfer type called a so-called tandem type, and has a plurality of image forming units 22 (22a to 22d) in which toner images of respective color components (in this example, four colors of yellow (Y), magenta (M), cyan (C), and black (K)) are formed by an electrophotographic method. A belt-shaped intermediate transfer body 23 is disposed at a position corresponding to each image forming unit 22, and a primary transfer device 24 (for example, a primary transfer roll) is disposed on the back surface of the intermediate transfer body 23 corresponding to each image forming unit 22. Further, a secondary transfer device (for example, a secondary transfer roll) 25 for secondarily transferring the toner images of respective color components primarily transferred from each image forming unit 22 to the intermediate transfer body 23 by the primary transfer device 24 to a recording material S such as paper is disposed on a part of the intermediate transfer body 23. A fixing device 60 is disposed on the downstream side in the conveyance direction of the recording material S on which the toner images of respective color components are transferred, and is configured to fix the unfixed toner image on the recording material S.

[0022] Here, each image forming unit 22 has a drum-shaped photoreceptor 30 that rotates in a predetermined direction. Around this photoreceptor 30, there are a charger 31 that charges the photoreceptor 30, an exposure device 32 such as a laser scanning device that writes an electrostatic latent image on the photoreceptor 30 charged by the charger 31, a developing device 33 that develops the electrostatic latent image written on the photoreceptor 30 with a corresponding color toner, and a cleaner 34 that cleans the residue on the photoreceptor 30 after the toner image developed by the developing device 33 is primarily transferred onto the intermediate transfer member 23 by the primary transfer device 24. Also, the intermediate transfer member 23 is stretched over a plurality of tension rollers 41 to 45 and, for example, circulates and rotates along a predetermined direction with the tension roller 41 as a driving roller. Further, the tension roller 44 also serves as an opposing roller for the secondary transfer roller of the secondary transfer device 25 and is configured to generate a secondary transfer electric field necessary for secondary transfer between the secondary transfer roller and the opposing roller. Additionally, an intermediate transfer cleaner 46 is disposed on the surface of the intermediate transfer member 23 corresponding to the tension roller 45. Furthermore, a recording material supply device 50 is provided below the intermediate transfer member 23, and the recording material S supplied from the recording material supply device 50 is conveyed along a conveyance path 51 that leads to the fixing device 60 via the secondary transfer device 25. Note that the conveyance path 51 is provided with an appropriate number of conveyance rollers 52, a conveyance belt 53 that conveys from the secondary transfer device 25 to the fixing device 60, guide plates 54 and 55 that guide the recording material S to the secondary transfer site by the secondary transfer device 25 and the fixing site of the fixing device 60, and a discharge roller 56 for discharging the recording material S to a recording material discharge section (not shown), etc.

[0023] -Fixing Device- Next, the fixing device 60 used in this embodiment will be described with reference to FIG. 3. In the figure, the fixing device 60 includes a fixing belt 61 made of a heat-resistant material that circulates and moves, a fixing area forming unit 62 that fixes the unfixed image of the recording material S in a fixing area m that sandwiches and conveys the recording material S between the fixing belt 61, a tensioning roll 63 that tensionally supports the fixing belt 61 so that it can circulate and move at a site away from the fixing area m of the fixing belt 61 toward the upstream side in the moving direction of the fixing belt, a resistance heating roll 64 that tensionally supports the fixing belt 61 so that it can circulate and move at a site away from the fixing area m of the fixing belt 61 toward the downstream side in the moving direction of the fixing belt and that contacts and heats the fixing belt 61 as a resistance heating component, and a wick 65 that contacts a site located between the tensioning roll 63 and the resistance heating roll 64 on the back surface of the fixing belt 61 and applies a lubricant.

[0024] First, among the components of the fixing device 60, other components except the resistance heating roll 64 will be described first, and then the resistance heating roll 64 will be described in detail. <Fixing Belt> In this example, the fixing belt 61 is configured with a resin material having heat resistance, such as a polyimide (PI) resin, as a base material, and an elastic layer such as silicone rubber is laminated on the surface of the base material, and a release layer made of a fluorine-based resin is laminated, and the thermal conductivity along the thickness direction and the surface direction is generally low. <Fixing Area Forming Unit> In this example, the fixing area forming unit 62 holds a plate-shaped pressing pad 70 (for example, made of SUS or liquid crystal polymer) as a plate-shaped receiving member that is arranged in contact with the back surface of the fixing belt 61 in a pad holder 71, and a pressing roll 72 as a pressing member is arranged on the surface of the fixing belt 61 so as to be pressed against the pressing pad 70. In this example, the pressing roll 72 is formed by laminating an elastic material such as urethane rubber around a metal roll, presses the fixing belt 61 toward the pressing pad 70 side, secures a predetermined fixing area m, and sandwiches and conveys the recording material S in the fixing area m as the fixing belt 61 moves. <Tensioning Roll> Since the supporting roll 63 is installed on the downstream side in the moving direction of the fixing belt 61 with respect to the resistance heating roll 64, there is a possibility that the thermal energy of the fixing belt 61 heated by the resistance heating roll 64 is lost at the contact portion with the supporting roll 63. Therefore, in order to suppress the heat loss from the supporting roll 63, it is preferable to provide a heat shielding protective layer (not shown) or the like effective for heat shielding on the surface of the supporting roll 63. <Wick> In this example, the wick 65 is formed by fixing a wick material 80 containing a lubricant to a wick holder 81 and arranging the tip of the wick material 80 in contact with the back surface of the fixing belt 61.

[0025] - Resistance heating roll - In this example, as shown in FIGS. 5 and 6(b), the resistance heating roll 64 includes a metal roll 90 made of a metal cylindrical tube as a base material, an insulating layer 91 laminated with a predetermined thickness over substantially the entire circumferential surface of the metal roll 90, a resistance heating layer 92 laminated over a region excluding a part near both ends of the circumferential surface of the metal roll 90 on the surface of the insulating layer 91, and a protective layer 93 made of polyimide or PEEK material laminated on the resistance heating layer 92. <Metal roll> In this example, the metal roll 90 is composed of a cylindrical tube made of, for example, high-tensile steel, and its wall thickness t is configured to be a thin wall of 0.2 to 1.0 mm. At this time, when the thickness is less than 0.2 mm, the rigidity is likely to be insufficient, and when it exceeds 1.0 mm, the effect of the startup performance is diminished. <Insulating layer> In this example, the insulating layer 91 can be appropriately selected, but for example, it is preferably composed of any one of polyimide (PI), polyamideimide (PAI), Diallyl phthalate (PDAP) and polyetheretherketone (PEEK). In particular, when using polyimide (PI), the insulating layer 91 can be accurately formed using the mold casting method described later. <Resistance heating layer> In this example, the resistance heating layer 92 is laminated with a substantially uniform thickness using a resistance heating material (e.g., silver palladium, gold palladium, carbon metal filler mixture) on the surface of the insulating layer 91 laminated on the surface of the metal roll 90, excluding a part near both ends. Note that the resistance heating layer 92 may be formed on the surface of the insulating layer 91 in a patterned pattern. <Protective layer> In this example, a protective layer 93 made of polyimide or PEEK material is formed over substantially the entire area of the resistance heating layer 92. When the resistance heating roll 64 is stretched over the back surface of the fixing belt 61, the resistance heating layer 92 does not come into direct contact with the back surface of the fixing belt 61, and the protective layer 93 comes into contact with the back surface of the fixing belt 61. This protective layer 93 has low releasability and is effective in increasing the wettability of the lubricant and the tack force for driving.

[0026] <Drive roll function of the resistance heating roll> In this example, the resistance heating roll 64 also functions as a drive roll for driving the fixing belt 61. That is, as shown in FIGS. 4(a)(b) and 5, the resistance heating roll 64 is rotatably held by bearing bearings 101 and 102 at portions where the insulating layer 91 near both ends thereof is exposed. A plurality of key grooves 103 (two in this example) are formed at one end side of the metal roll 90. A drive gear 104 is fitted outside the bearing bearing 101 at a portion where the insulating layer 91 near one end of the metal roll 90 is exposed. A detent projection 105 formed on the inner peripheral portion of the drive gear 104 is hooked on the key groove 103 of the metal roll 90 and is prevented from coming off by a clip 106, and the drive gear 104 is fixed to one end of the resistance heating roll 64. A drive force from a drive motor 110 is transmitted to the drive gear 104 through an input gear 111 that meshes therewith. The drive motor 110 is controlled according to a control signal from a control device 120, and the resistance heating roll 64 is driven as a drive roll as the input gear 111 rotates.

[0027] <Power supply structure of the resistance heating roll> In this example, as shown in FIG. 5 for example, the power supply structure of the resistance heating roll 64 is such that the protective layers 93 near both ends of the resistance heating layer 92 are removed, a ring-shaped electrode 121 is formed at the removed portion, a power supply contact 122 that contacts the electrode 121 is provided, and by turning on the heat generation start switch 123 according to a control signal from the control device 120, electric power from the power supply for power supply 124 is supplied from the power supply contact 122 to the resistance heating layer 92 via the electrode 121, causing the resistance heating layer 92 to generate heat. Note that the power supply structure of the resistance heating roll 64 is not limited to this, and it can be appropriately selected, such as supplying power from both end shaft portions of the metal roll 90.

[0028] <Manufacturing method of resistance heating roll> Next, the manufacturing method of the resistance heating roll 64 according to this embodiment will be described. In this example, since the metal roll 90 is high-tensile steel and the insulating layer 91 is polyimide (PI), the die casting coating method is adopted for the insulating layer forming process. More specifically described, in this example, the manufacturing method of the resistance heating roll 64 includes a layer forming process of sequentially forming the insulating layer 91, the resistance heating layer 92, and the protective layer 93 on the outer peripheral portion of the metal roll 90. Regarding at least the insulating layer forming process among the layer forming processes, as shown in FIG. 6(a), the metal roll 90 is positioned by the both-end positioning portions 131 and 132, and a die 130 that partitions a cavity portion 133 corresponding to the thickness of the insulating layer 91 to be formed between the outer peripheral portion of the metal roll 90 is used. The coating material M of the insulating layer 91 to be formed in the cavity portion 133 is poured from an injection port 134 communicating with the cavity portion 133, and the die casting coating method for coating the insulating layer 91 to be formed by baking is adopted. In this case, since the metal roll 90 is made of high-tensile steel, the cylindricity may be worse than that of a perfect circle due to the influence of its machining accuracy. However, according to the mold casting coating method, if the outer peripheral surface of the mold 130 is precisely formed, the roundness of the insulating layer 91 after mold forming is closer to a perfect circle than that of the metal roll 90. Therefore, when forming the resistive heating layer 92 on the insulating layer 91, it is preferable in that the layer thickness of the resistive heating layer 92 is more easily maintained uniformly compared to the case where the resistive heating layer 92 is directly formed on the surface of the metal roll 90. Also, regarding the surface roughness, the surface of the insulating layer 91 is preferably smoother than the surface of the metal roll 90.

[0029] In addition, in FIG. 6(a), reference numeral 135 indicates a seal member for restricting the region where the coating material M spreads among the cavity portions 133 in the mold 130 for forming each layer, where the regions where the insulating layer 91, the resistive heating layer 92, and the protective layer 93 are laminated on the outer peripheral portion of the metal roll 90 are various. In this example, since an example of performing the insulating layer forming process has been described, if the insulating layer 91 is to be formed over substantially the entire outer peripheral portion of the metal roll 90, the seal member 135 is not required. In this example, the mold casting coating method has been described by taking the insulating layer forming process as an example. However, if the mold casting coating method is adopted for the resistive heating layer forming process or the protective layer forming process, the mold should be prepared in advance according to the thickness of the resistive heating layer 92, the protective layer 93 to be formed, etc., such as the selection of the outer peripheral surface position and the inner peripheral surface position of the cavity portion 133, or the setting position of the seal member 135.

[0030] <Layout of the Resistive Heating Roll> In this example, the layout of the resistive heating roll 64 is as shown in FIG. 3. First, as shown in FIG. 3, since the resistive heating roll 64 uses a metal roll 90 with a large outer diameter, a wide region HT is secured where it is stretched over the fixing belt 61, and accordingly, a large amount of heat conduction from the resistive heating roll 64 to the fixing belt 61 is ensured. Further, when the distance from the contact center position P1 between the fixing belt 61 and the resistance heating roll 64 to the center position P2 of the fixing area m in the circulation moving direction of the fixing belt 61 is L1, and the distance from the center position B of the fixing area m to the contact center position P2 in the circulation moving direction of the fixing belt 61 is L2, in this example, it is selected to satisfy L1 > L2. The reason for such selection is as follows. That is, as shown in Fig. 7(a), the back side of the fixing belt 61 is heated with the heat quantity Q by the resistance heating roll 64. However, since the thermal conductivity of the fixing belt 61 is low, the surface side of the fixing belt 61 does not immediately rise in temperature by T. Therefore, in this example, by increasing the distance L2 of the fixing belt 61 until the fixing belt 61 heated by the resistance heating roll 64 reaches the fixing area m, as shown in Fig. 7(b), by gaining time for the heat heated on the back side of the fixing belt 61 to be conducted to the surface side, the surface temperature of the fixing belt 61 at P1 will rise sufficiently by the stage of reaching P2. The fixing belt 61 reaching the fixing area m will reach a state where its surface side is sufficiently heated, and sufficient heating energy in the fixing area m by the fixing belt 61 is ensured.

[0031] - Forms of deformation of the resistance heating component - ◎ Form of deformation 1 Fig. 8(a) shows a fixing device 60 according to the form of deformation 1. In the figure, the basic configuration of the fixing device 60 is substantially the same as that of the first embodiment. However, different from the first embodiment, an auxiliary heating source 140 such as a halogen lamp is separately added in the pad holder 71 on the back side of the fixing area m. In this example, rather than actively heating the fixing belt 61 located in the fixing area m, when the recording material S is nipped and conveyed in the fixing area m, since heat loss from each element of the recording material S and the fixing area forming portion 62 is inevitable, the auxiliary heating source 140 is to avoid an increase in heat loss from the fixing belt 61 in the fixing area m by compensating for this heat loss.

[0032] ◎ Form of deformation 2 Fig. 8(b) shows a resistance heating roll according to the form of deformation 2. In the figure, the resistance heating roll 64 includes an insulating layer 91, a resistance heating layer 92, and a protective layer 93 on the outer surface of the metal roll 90. Further, a resistance heating layer 96 is formed on the inner surface of the metal roll 90 via an insulating layer 95. This is preferable in that the heat generation efficiency by the resistance heating roll 64 is higher than that in the first embodiment. ◎ Modified Form 3 FIG. 8(c) shows that, as the resistance heating component 150 in the fixing belt 61, instead of the metal roll 90, a flat base material 151 is prepared, and an insulating layer 152, a resistance heating layer 153, and a protective layer 154 made of polyimide or PEEK material are laminated on the surface of this base material 151, and the resistance heating component 150 is brought into contact with the back surface of the fixing belt 61.

Explanation of Reference Numerals

[0033] 1... Resistance heating component, 2... Base material, 2a... Metal roll, 3... Resistance heating layer, 4... Insulating layer, 5... Protective layer, 7... Mold, 7a... Inlet, 7b... Cavity, 10... Fixing device, 11... Fixing belt, 12... Fixing area forming means, 12a... Pressing member, 12b... Receiving member, 13... Tensioning member, 15... Image forming means, 16... Recording material, m... Fixing area, M... Coating material

Claims

1. A fixing belt made of a heat-resistant material that moves in a cycle, Fixing area forming means for fixing an unfixed image of a recording material in a fixing area where the recording material is sandwiched and conveyed between the fixing belt, A resistance heating component that contacts and heats the fixing belt at a portion of the fixing belt away from the fixing area, and is provided with: The resistance heating component includes a metal base material, A resistance heating layer laminated on the front or back surface of the base material via an insulating layer, And is provided with: The resistance heating component is disposed in contact with the back surface of the fixing belt, A fixing device, wherein a distance L1 from a contact center position of the resistance heating component with the fixing belt to a center position of the fixing area in a circulation movement direction of the fixing belt is longer than a distance L2 from the center position of the fixing area to the contact center position in the circulation movement direction of the fixing belt.

2. In the fixing device according to Claim 1, The resistance heating component, A base material that is a roll made of a metal cylindrical body, A resistance heating layer laminated on the surface of the base material via an insulating layer, A protective layer that covers the resistance heating layer and contacts the back surface of the fixing belt, An electrode that contacts a surface in a thickness direction of the resistance heating layer not covered by the protective layer and supplies electric power from a power supply for power supply to the resistance heating layer, A fixing device characterized by comprising:

3. In the fixing device according to Claim 1, The fixing device, wherein the base material is configured to have a thickness of 0.2 to 1.0 mm.

4. In the fixing device according to Claim 1, The fixing device, wherein the insulating layer is configured using any one of polyimide (PI), polyamideimide (PAI), diallyl phthalate (PDAP), and polyetheretherketone (PEEK).

5. In the fixing device according to Claim 1, The fixing device, wherein the resistance heating component functions as a tensioning roll for tensioning the fixing belt.

6. In the fixing device according to Claim 1, The fixing device, wherein the resistance heating component functions as a tensioning roll for tensioning the fixing belt and also functions as a driving roll for driving the fixing belt.

7. In the fixing device according to any one of Claims 1 to 6, The fixing device, wherein the fixing area forming means includes an auxiliary heating element that suppresses heat loss when the fixing belt heated by the resistance heating component passes through the fixing area.

8. A resistance heating component that contacts a fixing belt made of a heat-resistant material and is heated, and is provided at a portion away from a fixing area where a recording material is sandwiched and conveyed between the fixing belt. When manufacturing a resistance heating component including a metal roll formed of a cylindrical body as a metal base material and a resistance heating layer laminated on an outer surface or an inner surface of the metal roll via an insulating layer, A layer forming step of sequentially forming a laminate including an insulating layer and a resistance heating layer on an outer peripheral portion or an inner peripheral portion of the metal roll is provided. Among each layer forming step, at least the insulating layer forming step positions the metal roll and uses a mold that partitions a cavity corresponding to the thickness of the layer to be formed between the outer peripheral portion or the inner peripheral portion of the metal roll, and pours a coating material of the layer to be formed into the cavity and bakes it to apply the layer to be formed. A method for manufacturing a resistance heating component, characterized by adopting a mold pouring coating method.

9. In the method for manufacturing a resistance heating component according to Claim 8, The metal roll is high-tensile steel, and the coating material of the insulating layer uses polyimide. A method for manufacturing a resistance heating component, characterized by this.

10. In the method for manufacturing a resistance heating component according to Claim 9, The cylindricity of the outer peripheral surface of the insulating layer is closer to a cylinder than the cylindricity of the metal roll. A method for manufacturing a resistance heating component, characterized by this.

11. In the method for manufacturing a resistance heating component according to Claim 8, Among each layer forming step, the resistance heating layer forming step also forms the resistance heating layer using the mold pouring coating method. A method for manufacturing a resistance heating component, characterized by this.

12. Image forming means for forming an image on a recording material, A fixing device according to any one of Claims 1 to 7 for fixing an unfixed image formed by the image forming means, An image forming apparatus, characterized by comprising the above.

Images