Heating device, image forming apparatus, heater, and heater holder

Abstract

To provide a heater that can reduce the size of a heating device.SOLUTION: A heater 22 comprises: a heating element 223; an electrode 226 for supplying power to the heating element 223; and a slender substrate 221 on which the heating element 223 and the electrode 226 are provided. The substrate 221 has a heating element installation part 221a that extends in a longitudinal direction, and an electrode installation part 221b that is located bent from one end in the longitudinal direction of the heating element installation part 221a. The heating element 223 is arranged in the heating element installation part 221b, and the electrode 226 is arranged in the electrode installation part 221b.SELECTED DRAWING: Figure 6

Description

[Technical Field]

[0001] The present invention relates to a heating device such as a fixing device mounted in an image forming apparatus such as a copying machine or printer using an electrophotographic or electrostatic recording system, or a gloss imparting device that improves the glossiness of a toner image by reheating a fixed toner image on a recording material, and also to an image forming apparatus equipped with such a heating device, and further to a heater and heater holder used in the heating device. [Background technology]

[0002] A common heating device installed in an electrophotographic printer or copier is one that includes a heater having a heating element on a substrate, a film that moves while in contact with the heater, and a pressure roller that forms a nip with the heater via the film. Metal substrates are sometimes used as the substrates for the heaters in such devices because of their strength against thermal stress.

[0003] Patent Document 1 discloses a configuration in which the metal substrate of the heater is bent and the heater is engaged with a heater holder so that movement of the heater is restricted, thereby reducing the number of parts such as heater clips. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Japanese Patent Application Publication No. 2019-164996 Summary of the Invention [Problem to be solved by the invention]

[0005] However, in the above configuration, the heating element and the electrodes for supplying power to the heating element are arranged adjacent to each other in the longitudinal direction on the same plane of the substrate, so it is not possible to miniaturize the heater, and therefore the heating device and image forming device.

[0006] The present invention has been made in view of the above-mentioned problems, and has an object to provide a heater that enables the heating device to be made smaller. [Means for solving the problem]

[0007] In order to achieve the above object, the heater of the present invention comprises: A heating element; an electrode for supplying power to the heating element; an elongated substrate on which the heating element and the electrodes are provided; In a heater comprising: The substrate is a flat surface on which the heating element is provided, a heating element installation portion extending in the longitudinal direction; an electrode installation portion bent from one end of the heat generating element installation portion in the longitudinal direction; and The heating element is disposed in the heating element mounting portion, and the electrode is disposed in the electrode mounting portion. 、 The electrode placement portion extends parallel to the plane. It is characterized by the following. In order to achieve the above object, the heating device of the present invention comprises: a first rotating body; a heater including a heating element, an electrode for supplying power to the heating element, and an elongated substrate on which the heating element and the electrode are provided, the heater being provided in the internal space of the first rotating body; a second rotating body that forms a nip portion with the heater via the first rotating body; a heater holder that holds the heater and guides the rotation of the first rotating body; Equipped with The substrate is a heating element installation portion extending in the longitudinal direction and forming the nip portion together with the second rotating body; an electrode installation portion bent from one end of the heat generating element installation portion in the longitudinal direction; and the heating element is disposed in the heating element mounting portion, and the electrodes are disposed in the electrode mounting portion; The heater holder is characterized by being provided with a power supply means for supplying power to the electrodes. In order to achieve the above object, the image forming apparatus of the present invention comprises: an image forming section for forming an image on a recording material; a heating device for fixing an image formed on a recording material to the recording material; a housing in which the image forming unit and the heating device are provided; An image forming apparatus having The heating device is a first rotating body; a heater including a heating element, an electrode for supplying power to the heating element, and an elongated substrate on which the heating element and the electrode are provided, the heater being provided in the internal space of the first rotating body; a second rotating body that forms a nip portion with the heater via the first rotating body; Equipped with The substrate is a heating element installation portion extending in the longitudinal direction and forming the nip portion together with the second rotating body; an electrode installation portion bent from one end of the heat generating element installation portion in the longitudinal direction; and the heating element is disposed in the heating element mounting portion, and the electrodes are disposed in the electrode mounting portion; The present invention is characterized in that a power supply means for supplying power to the electrodes is provided on the surface of the housing facing the heater at the one end side in the longitudinal direction of the substrate. In order to achieve the above object, the heater holder of the present invention comprises: A heater holder for holding a heater including a heating element, an electrode for supplying power to the heating element, and an elongated substrate on which the heating element and the electrode are provided, a holding portion into which a part of the heater is inserted and which holds the heater; a power supply means provided in the holding portion and supplying power to the electrode; and The power supply means is connected to electrodes provided on the heater inserted into the holding portion. [Effects of the Invention]

[0008] According to the present invention, it is possible to provide a heater that enables the heating device to be made smaller. [Brief explanation of the drawings]

[0009] [Figure 1] 1 is a schematic configuration diagram of an image forming apparatus according to a first embodiment. [Figure 2] FIG. 2 is a cross-sectional view of the fixing device according to the first embodiment. [Figure 3] FIG. 2 is an exploded perspective view of a heater holder unit and peripheral components according to the first embodiment. [Figure 4] FIG. 2 is a front view of the fixing device according to the first embodiment. [Figure 5] FIG. 2 is a cross-sectional view of the heater according to the first embodiment. [Figure 6] FIG. 1 is a perspective view of a heater according to a first embodiment. [Figure 7]FIG. 2 is a perspective view of a heater and a power supply unit according to the first embodiment. [Figure 8] FIG. 2 is a perspective view of a heater holder unit according to the first embodiment. [Figure 9] FIG. 10 is a perspective view of a heater holder unit according to a conventional example. [Figure 10] FIG. 10 is a perspective view of a heater holder unit and a power supply unit according to a second embodiment. [Figure 11] FIG. 10 is a perspective view of a heater according to a third embodiment. [Figure 12] FIG. 10 is a perspective view of a heater holder and a power supply unit according to a third embodiment. [Figure 13] FIG. 10 is a perspective view of a heater holder unit according to a third embodiment. [Figure 14] FIG. 10 is a perspective view of a heater holder unit and a power supply unit according to a fourth embodiment. [Figure 15] FIG. 10 is a perspective view of a heater according to a modified example. [Figure 16] FIG. 10 is a perspective view of a heater according to a modified example. [Figure 17] FIG. 10 is a perspective view of a heater holder unit and a power supply unit according to a modified example. DETAILED DESCRIPTION OF THE INVENTION

[0010] The following describes in detail, by way of example, the mode for carrying out the present invention with reference to the drawings. However, the dimensions, materials, shapes, and relative positions of the components described in the examples should be appropriately changed depending on the configuration of the device to which the invention is applied and various conditions. In other words, the scope of the present invention is not intended to be limited to the following embodiments. Image forming devices to which the present invention can be applied include printers and copiers that use electrophotography or electrostatic recording methods, and the following description will be given of the application to a laser printer.

[0011] Example 1 (1) Image forming apparatus 100 1 is a schematic diagram of an image forming apparatus 100 using electrophotographic recording technology according to embodiment 1. First, the configuration and operation of the image forming apparatus 100 will be described.

[0012] The image forming operation in the image forming section of the image forming apparatus 100 will be described. When the image forming apparatus 100 receives a print command from an external device, the scanner unit 3 emits a laser beam L corresponding to the image information toward the photoconductor 1. The photoconductor 1, which has been charged to a predetermined polarity by the charging roller 2, is scanned by the laser beam L, and an electrostatic latent image corresponding to the image information is formed on the surface of the photoconductor 1. The developer 4 then supplies toner to the photoconductor 1, and a toner image corresponding to the image information is formed on the photoconductor 1. As the photoconductor 1 rotates in the direction of arrow R, the toner image on the photoconductor 1 moves to a transfer position formed by the photoconductor 1 and transfer roller 5, and is transferred to a recording material P fed from a cassette 6 by a pickup roller 7. After passing the transfer position, the surface of the photoconductor 1 is cleaned by a cleaner 8.

[0013] The recording material P onto which the toner image has been transferred in the image forming unit is fixed by heat and pressure in a fixing device 9 serving as a fixing unit. Thereafter, the recording material P is discharged onto a discharge tray 11 by a discharge roller 10.

[0014] (2) Fixing device 9 Next, the configuration and operation of the fixing device 9 will be described. In this embodiment, a tensionless film heating type fixing device 9 is used as an example of a heating device. The fixing device 9 of this embodiment uses an endless belt-shaped (or cylindrical) heat-resistant film, and at least a portion of the circumferential length of the film is always tension-free (in a state where no tension is applied), and the film is rotationally driven by the rotational driving force of a pressure member.

[0015] Fig. 2 is a schematic cross-sectional view of the fixing device 9 of this embodiment, showing how a recording material P carrying a toner image is conveyed to the fixing device 9. Fig. 3 is an exploded perspective view of the heater holder unit 20 and peripheral components. Fig. 4 is a schematic front view of the fixing device 9, in which part of the film 23 is not shown in order to show the internal space of the film 23.

[0016] The configuration of the fixing device 9 will be described with reference to Figure 2. The fixing device 9 of this embodiment has a cylindrical film 23 as a first rotating body, a heater 22 that heats the film 23 in the internal space of the film 23, and a pressure roller 30 as a second rotating body that forms a nip N with the heater 22 via the film 23. The fixing device 9 further has a heater holder 21 that supports the heater 22 and guides the rotation of the film 23, and a reinforcing member 24 that reinforces the heater holder 21. The pressure roller 30 receives power from a motor (not shown) and rotates in the direction of arrow b, causing the film 23 to rotate in the direction of arrow a.

[0017] The film 23 is a cylindrical rotating body. The thickness of the film 23 is preferably approximately 20 μm or more and 100 μm or less to ensure good thermal conductivity. When the film 23 is a single-layer film, the base layer is preferably made of a material such as PTFE (polytetrafluoroethylene), PFA (tetrafluoroethylene-perfluoroalkyl vinyl ether), or PPS. When the film 23 is a composite-layer film, the base layer is preferably made of a material such as PI (polyimide), PAI (polyamide imide), PEEK (polyether ether ketone), or PES (polyether sulfone). Furthermore, it is preferable to form a composite-layer film using a material such as PTFE, PFA, or FEP (tetrafluoroethylene-perfluoroalkyl vinyl ether) as a release layer coated on the surface of the base layer. It is also preferable to use a pure metal or alloy such as SUS, Al, Ni, Cu, or Zn with high thermal conductivity as the base layer, and then subject the release layer to the aforementioned coating treatment or a fluororesin tube.

[0018] The film 23 of this example is a composite layer film in which the base layer is made of PI with a thickness of 60 μm and is coated with a release layer made of PFA with a thickness of 12 μm to balance between wear resistance due to paper passing and thermal conductivity. The axial direction of the cylindrical shape of the film 23 is hereinafter referred to as the longitudinal direction.

[0019] The heater holder 21 is a support member located within the internal space of the film 23 and supports the heater 22. The film 23 is loosely fitted over the heater holder 21, which also functions as a guide for guiding the rotation of the film 23 while sliding against the inner surface of the film 23. High-heat-resistant resins such as polyimide, polyamide-imide, PEEK, PPS, and liquid crystal polymers, as well as composite materials of these resins with ceramics, metals, glass, and other materials, are suitable for the heater holder 21. Liquid crystal polymers are particularly suitable for use due to the following advantages: First, their high heat resistance allows for greater flexibility in heater temperature setting. Furthermore, their moldability allows for high productivity and mass production. Furthermore, their excellent dimensional stability allows for uniform pressure on the pressure member, resulting in stable paper transport performance. In this example, a composite material made of liquid crystal polymer mixed with glass fiber was used.

[0020] The heater 22 as a heat-generating member has a long and narrow substrate made mainly of metal, a heat-generating element that generates heat when electricity is applied, an insulating layer that insulates the heat-generating element from the substrate, and a glass coating layer that protects the heat-generating element. The detailed configuration of the heater 22 will be described later.

[0021] The thermistor 25, which is a temperature detection member, is in contact with the contact surface of the heater 22 with the heater holder 21. The power supply to the heating resistor is controlled in accordance with the temperature detected by the thermistor 25, thereby managing the temperatures of the heater 22 and the film 23. That is, the thermistor 25 detects a change in temperature of the film 23 via the heater 22.

[0022] The pressure roller 30 has a core metal made of iron, aluminum, or the like, an elastic layer made of silicone rubber, or the like, and a release layer made of PFA, etc. A drive gear 33 (see FIG. 4) is attached to one longitudinal end of the core metal of the pressure roller 30, and the drive gear 33 receives a rotational drive force from a drive means (not shown), causing the pressure roller 30 to rotate.

[0023] The reinforcing member 24 is made of a metal such as iron and is a member that maintains strength so as not to be significantly deformed even when subjected to pressure pressing the heater holder 21 toward the pressure roller 30. The heater 22 is pressed toward the pressure roller 30 via the heater holder 21 and the reinforcing member 24 by a pressing means, which will be described later. The area where the pressure roller 30 and the film 23 are pressed together is the nip portion N.

[0024] Next, the heater holder unit 20, which is composed of components such as the heater 22, and its peripheral components will be described in detail with reference to the perspective view of Figure 3. The heater 22 is held by a heater holder 21, and is positioned relative to the heater holder 21 by a heater clip 28 provided at the end in the longitudinal direction. The heater clip 28 is formed from a metal plate bent into a C-shape, and holds the end of the heater 22 relative to the heater holder 21 by its spring property. The heater holder unit 20 of this embodiment is composed of the heater holder 21, the heater 22, and the heater clip 28.

[0025] The heater holder 21 has a generally trough-shaped cross section perpendicular to the longitudinal direction, and the reinforcing member 24 fits inside the tub-shaped section. A heater receiving groove is provided on the side of the heater holder 21 facing the pressure roller 30, and the heater 22 fits into the heater receiving groove and is fitted at the desired position. The film 23 is fitted around the outside of the heater holder 21, on which the above-mentioned components are assembled, with some circumferential margin. Both longitudinal ends of the reinforcing member 24 protrude outward beyond both ends of the film 23, and flanges 26 are fitted onto each end of the reinforcing member 24.

[0026] Next, the configuration of fixing device 9 will be described in more detail with reference to Fig. 4. In Fig. 4, a portion of film 23 is not shown so that heater holder 21 and heater 22 provided in the internal space of film 23 can be seen. Flanges 26 located at both ends of film 23 restrict movement of film 23 in the longitudinal direction as it rotates and travels.

[0027] The heater holder unit 20 is disposed opposite the pressure roller 30 and is supported by the top-side housing 41 via a flange 26 or the like. The heater holder unit 20 is supported by the top-side housing 41 so as to be able to move freely in the pressure direction, and its movement in the longitudinal direction is restricted by the side-side housing 42. A pressure spring 45 is attached in a compressed state to the top-side housing 41 of the fixing device 9. The pressing force of the pressure spring 45 is received by both longitudinal ends of the reinforcing member 24 via the flange 26. The pressing force of the pressure spring 45 presses the reinforcing member 24 toward the pressure roller 30, and the heater holder unit 20 toward the pressure roller 30, forming a nip N between the film 23 and the pressure roller 30.

[0028] The bearing member 31 is provided to support the core metal of the pressure roller 30, and receives the pressing force from the heater holder unit 20 via the pressure roller 30. A material having heat resistance and excellent sliding properties is used for the bearing member 31 in order to rotatably support the core metal of the roller 30. The bearing member 31 is attached to the bottom housing 43 of the fixing device 9.

[0029] (3) Heater 22 Next, the heater 22 of this embodiment will be described in detail. First, the material constituting the heater 22, the manufacturing method, etc. will be described with reference to FIG.

[0030] 5 is a cross-sectional view of heater 22. It has a long, narrow substrate 221 made primarily of metal, a heating element 223 that generates heat when electricity is applied, an insulating layer 222 that insulates heating element 223 from substrate 221, and a protective layer 224 that protects heating element 223. In order to prevent warping of the substrate during manufacturing, an insulating layer 225 is also provided on the surface of substrate 221 opposite to the surface on which heating element 223 is provided. Heating element 223 is provided on the surface of substrate 221 that faces pressure roller 30.

[0031] Suitable materials for the substrate 221 include stainless steel, nickel, copper, aluminum, and alloys containing these as the main material. Of these, stainless steel is most preferred from the viewpoints of strength, heat resistance, and corrosion. There are no particular limitations on the type of stainless steel, and it may be selected appropriately taking into consideration the required mechanical strength, the linear expansion coefficient suited to the formation of the insulating layer 222 and the heating element 223, the ease of obtaining the plate material on the market, and other factors. As an example, martensitic and ferritic chromium-based stainless steel (400 series) has a relatively low linear expansion coefficient among stainless steels, making it suitable for use as an insulating layer and heating element.

[0032] The thickness of the substrate 221 can be determined taking into consideration its strength, heat capacity, and heat dissipation performance. A thin substrate has a small heat capacity, which is advantageous for quick start-up, but if it is too thin, problems such as distortion are more likely to occur when the heating element is heated and formed. Conversely, a thick substrate is advantageous in terms of distortion when the heating element is heated and formed, but if it is too thick, it has a large heat capacity, which is disadvantageous for quick start-up. The preferred thickness of the substrate 221 is 0.3 mm to 2.0 mm, taking into consideration the balance between mass productivity, cost, and performance.

[0033] The substrate 221 in this example is a ferritic stainless steel substrate (SUS430: 18Cr stainless steel) having a width of 20 mm, a length of 376 mm and a thickness of 0.3 mm. The shape of the substrate 221, which is characteristic of the present invention, will be described in detail later.

[0034] The material of the insulating layers 222 and 225 is not particularly limited, but a heat-resistant material must be selected taking into account the temperature of actual use. Glass and PI (polyimide) are preferred materials from the viewpoint of heat resistance, and the specific powder material for glass may be selected appropriately as long as it does not impair the characteristics of the present invention. A thermally conductive filler having insulating properties may be mixed in as needed. The material and thickness of the insulating layers 222 and 225 may be the same, or may be changed as needed.

[0035] Generally, it is preferable that a heater used in an image forming apparatus has a dielectric strength of about 1.5 kV. Therefore, in order to obtain a dielectric strength of 1.5 kV between the heating element 223 and the substrate 221, the thickness of the insulating layer 222 should be secured according to the material.

[0036] The method for forming the insulating layers 222, 225 and the heating element 223 described later is not particularly limited, but as an example, they can be formed smoothly by screen printing or the like. The bent portions of the heater described below can also be formed by screen printing or the like. When forming an insulating layer of glass or PI (polyimide) on the substrate 221, it is necessary to appropriately adjust the linear expansion coefficients of the substrate and the insulating layer material so that cracks and peeling do not occur in the insulating layer due to differences in the linear expansion coefficients between the materials. be.

[0037] In this example, insulating layer glass paste was applied to a stainless steel substrate 221 by screen printing, and then the paste was dried at 180° C. and fired at 850° C. to form insulating layers 222 and 225. The insulating layers after firing had a thickness of 25 μm and were formed on both sides of the substrate 221.

[0038] The heating element 223 is formed by printing a heating resistor paste containing a mixture of (A) a conductive component, (B) a glass component, and (C) an organic binder component on the insulating layer 222 and then firing the paste. When the heating resistor paste is fired, the organic binder component (C) is burned away, leaving the components (A) and (B), forming the heating element 223 containing the conductive component and the glass component. Here, the conductive component (A) is preferably silver-palladium (Ag-Pd), ruthenium oxide (RuO), or the like, used alone or in combination, and has a sheet resistance of 0.1 [Ω / □] to 100 [kΩ / □]. Furthermore, it is acceptable to include other materials in addition to the above (A) to (C) in trace amounts that do not impair the characteristics of the present invention.

[0039] The power supply electrode 226 and the conductive pattern 227 are mainly made of silver (Ag), platinum (Pt), gold (Au), a silver-platinum (Ag-Pt) alloy, a silver-palladium (Ag-Pd) alloy, etc. The power supply electrode 226 and the conductive pattern 227 are formed by printing a paste, similar to the heating resistor paste, which is a mixture of (A) a conductive component, (B) a glass component, and (C) an organic binding component on the insulating layer 222 and then firing the paste.

[0040] The power supply electrode 226 and the conductive pattern 227 as a conductor are provided for the purpose of supplying power to the heating element 223, and their resistance is set sufficiently low compared to the heating element 223. Here, for the heating resistor paste, power supply electrode, and conductive pattern paste, materials that soften and melt at a temperature lower than the melting point of the substrate 221 must be selected, and heat-resistant materials must be selected taking into account the temperatures in actual use.

[0041] In this example, a heating resistor paste containing silver-palladium (Ag-Pd) as the conductive component, a mixture of other glass components and an organic binder component, and a power supply electrode and conductive pattern paste containing silver as the conductive component, a mixture of other glass components and an organic binder component, were used. Each paste was applied by screen printing to a stainless steel substrate 221 provided with insulating layers 222 and 225, and then dried at 180°C and fired at 850°C to form a heating element 223, a power supply electrode 226, and a conductive pattern 227. After firing, the heating element 223 had a thickness of 15 μm, a length of 312 mm, and a width of 1.1 mm.

[0042] Protective layer 224 is provided so as to cover heating element 223 and conductive pattern 227. When heating element 223 is arranged on the side that comes into contact with film 23, protective layer 224 is provided as a protective layer to ensure electrical insulation between heating element 223 and film 23 and to ensure sliding properties between heating element 223 and film 23. As materials, glass or PI (polyimide) are preferred from the viewpoint of heat resistance, and a thermally conductive filler having insulating properties may be mixed as needed.

[0043] In this example, a protective layer glass paste was prepared, and the protective layer glass paste was applied to the heating element 223 and the conductive pattern 227 by screen printing, and then dried at 180° C. and fired at 850° C. to form the protective layer 224. The thickness of the fired protective layer 224 was 30 μm.

[0044] Next, the shape of the heater 22, which is characteristic of the present invention, will be described with reference to FIG. 6. FIG. 6 is a perspective view showing the configuration of the heater 22 of this embodiment. The substrate 221 of the heater 22 of this embodiment is bent in the longitudinal direction, and is formed by bending the end portion in the longitudinal direction by 90 degrees. A heating element 223 and a power supply electrode 226 are provided on the substrate 221, and the substrate 221 has a heating element installation portion 221a, an electrode installation portion 221b, and a bent portion 221c.

[0045] The heat generating element mounting portion 221a extends linearly in a direction perpendicular to the conveyance direction of the recording material P in the nip portion N, and two heat generating elements 223 are disposed therein. The heat generating element mounting portion 221a forms the nip portion N with the pressure roller 30 via the film 23. The bent portion 221c extends from one end of the heat generating element mounting portion 221a in the longitudinal direction so as to bend toward the thickness direction of the heat generating element mounting portion 221a. The electrode mounting portion 221b extends perpendicular to the heat generating element mounting portion 221a, and is provided with a power supply electrode 226 to which power is supplied for energizing the heat generating element 223. In the fixing device 9 of this embodiment, the thickness direction of the heat generating element mounting portion 221a is parallel to the pressure direction of the recording material P. Note that the terms "perpendicular," "perpendicular," and "parallel" do not need to be strictly defined, as long as the image forming device can function as such.

[0046] That is, in this embodiment, the heating element 223 and the power supply electrode 226 are not on the same plane, and the conductive pattern 227 extends from the heating element installation portion 221a to the electrode installation portion 221b via the bent portion 221c. In other words, a characteristic feature of the present invention is that the substrate 221 is bent so that the planar heating element installation portion 221a and the electrode installation portion 221b extend perpendicular to each other.

[0047] Note that the bending described above does not necessarily mean forming a substrate by bending a plate material. For example, even if a substrate having a similar shape formed by means of casting, cutting, or the like is provided, the effect of miniaturizing the heating device described below can be expected. In other words, in this embodiment, the substrate was formed using bending as a processing method that can be expected to facilitate processing and improve the strength of the substrate through plastic processing, but the substrate forming method of the present invention is not limited to plastic processing.

[0048] (4) Method of holding and powering the heater 22 Next, the heater holder unit 20, which is composed of the heater holder 21, the heater 22, and the heater clip 28, will be described in detail with reference to Figures 7 and 8. Figure 7 is a perspective view showing one longitudinal end side of the heater holder unit 20 of this embodiment, where the power supply contact 211 is provided. Figure 8 is a perspective view showing the heater holder unit 20 in a state where the heater 22 is engaged with the heater holder 21.

[0049] The heater holder 21 of this embodiment has a holding portion 21a at one end in the longitudinal direction into which the electrode installation portion 221b of the heater 22 is inserted, and a power supply contact 211 is provided within the holding portion 21a as a power supply means. The heater 22 is held by the heater holder 21 in a state where a portion of the heater 22 including the electrode installation portion 221b, on which the power supply electrode 226 is provided, is inserted into the holding portion 21a of the heater holder 21. That is, the electrode installation portion 221b is provided on the side of the heating element installation portion 221a that is farther from the nip portion N in the thickness direction of the heating element installation portion 221a. When the electrode installation portion 221b of the heater 22 is inserted into the holding portion 21a of the heater holder 21, the power supply electrode 226 on the electrode installation portion 221b and the power supply contact 211 within the heater holder come into contact with a contact pressure.

[0050] The power supply contact 211 in the heater holder 21 is electrically connected to a wire bundle 29 that serves as a current path from the control means. Control by a control means (not shown) (for example, a conventionally known current-on / off control means using a triac) in accordance with the temperature detected by the thermistor 25 is performed by energizing the heater 22 through the wire bundle 29.

[0051] One longitudinal end of the heater 22 is positioned and held by inserting the electrode installation part 221b, on which the power supply electrode 226 is provided, into the holding part 21a. Furthermore, the other longitudinal end of the heater 22 opposite to the one longitudinal end is positioned by the heater clip 28. In this way, the heater 22 is held in a state where both ends are positioned, so that the heater 22 can be easily moved when heated. Even if the cable expands due to thermal expansion, the power supply part will not shift and electricity can be maintained.

[0052] (5) Effects To confirm the effects of the present invention, this example was compared with a comparative example having a conventional configuration. FIG. 9 is a perspective view showing a heater holder unit 50 of the comparative example. The heater holder unit 50 of the comparative example is composed of a heater holder 51, a heater 52, a heater clip 28, and a power supply connector 27. The heater 52 of the comparative example has a heating element 223 and a power supply electrode 226 mounted on the same plane of a substrate 521, and is positioned relative to the heater holder 51 by being held at both longitudinal ends by the heater clip 28 and the power supply connector 27. Furthermore, a power supply contact is provided within the power supply connector 27, which serves as a power supply means. The power supply contact within the power supply connector 27 comes into contact with the power supply electrode 226 of the heater 52, enabling power to be supplied to the heater 52. In other words, the conventional configuration can be said to be a configuration in which the heating element and the power supply electrode are mounted on the same plane of the substrate, and the power supply electrode is provided on an extension of the heating element in the longitudinal direction.

[0053] Comparing the heater holder unit of this example with that of the comparative example, the heater holder unit of this example was approximately 7 mm smaller in the longitudinal direction. In other words, by bending the heater substrate and providing electrodes on a surface different from the surface on which the heating element is provided, and by supplying power to the heater from a power supply contact provided within the heater holder, the heater holder unit was able to be made smaller in the longitudinal direction. Furthermore, by eliminating the power supply connector, it is expected that the heater holder unit will also be made smaller in the transport direction, depending on the device configuration.

[0054] As described above, according to the present invention, the heater holder unit does not require a power supply connector, thereby reducing the space required for providing the power supply connector. Furthermore, since the power supply contacts, which require a certain width, are provided on a plane different from the plane on which the heating element is provided, it is possible to reduce the size of the heater holder unit, and therefore the size of the fixing device and image forming apparatus.

[0055] <Example 2> Next, a second embodiment of the present invention will be described. The second embodiment has a configuration different from the first embodiment in the method of supplying power to the heater. Of the configuration of the second embodiment, the same components as those of the first embodiment are denoted by the same reference numerals and the description thereof will be omitted. Below, the characteristic configuration of the second embodiment will be described with reference to FIG. 10.

[0056] FIG. 10 is a schematic perspective view showing the heater holder unit 60 and power supply means of this embodiment. The heater 22 provided in the heater holder unit 60 is similar to that of the first embodiment and has a bent portion. The heater holder 61 holds the heater 22 but does not have a power supply means, as in the first embodiment. The electrode installation portion 221b, on which the power supply electrode 226 of the heater 22 of this embodiment is provided, is provided at one longitudinal end of the heater holder unit 60. When the heater holder unit 60 is incorporated into the image forming apparatus, the electrode installation portion 221b faces the side housing 42, and the power supply electrode 226 contacts with a contact pressure a power supply contact 421, which serves as a power supply means, provided on the side housing 42. That is, in the image forming apparatus of this embodiment, power is supplied to the heater from the power supply control means via the power supply means provided on the housing.

[0057] Comparing the heater holder unit of this embodiment with the heater holder unit of the comparative example described above, which has a conventional configuration, the heater holder unit of this embodiment is approximately 12 mm smaller in the longitudinal direction. In other words, by providing the power supply means on the housing of the image forming apparatus rather than inside the heater holder, the heater holder unit is smaller in size than the heater holder unit of the comparative example described above. Further space saving effect in the longitudinal direction can be obtained.

[0058] Example 3 Next, a third embodiment of the present invention will be described. The third embodiment has a configuration different from that of the first embodiment in terms of the shape of the heater. Of the configuration of the third embodiment, the same configuration as that of the first embodiment will be denoted by the same reference numerals. The characteristic configuration of the third embodiment will be described below with reference to FIGS.

[0059] Fig. 11(a) is a schematic perspective view of the heater 72 of this embodiment as seen from the heating element 223 side, and Fig. 11(b) is a schematic perspective view as seen from the power supply electrode 226 side. The substrate 721 of the heater 72 of this embodiment is bent by two bent portions 721c so that the heating element installation portion 721a and the electrode installation portion 721b extend parallel to each other. In other words, the substrate 721 is shaped so that the longitudinal ends are bent 180°.

[0060] 12 is a schematic perspective view showing the heater holder 71 of this embodiment and a power supply contact 77 as a power supply means. The power supply contact 77 of this embodiment is disposed near the end of the heater holder 71 in the longitudinal direction, on the opposite side from the side facing the nip portion N.

[0061] Fig. 13(a) is a schematic perspective view of the heater holder unit 70 of this embodiment as seen from the electrode installation portion 721b side, and Fig. 13(b) is a schematic perspective view as seen from the heating element installation portion 721a side. The heater 72 of this embodiment is arranged so that the heating element installation portion 721a and the electrode installation portion 721b sandwich the heater holder 71. The heater 72 held by the heater holder 71 in this state is arranged inside the image forming apparatus so that the power supply electrode 226 comes into contact with the power supply contact 77 with abutment pressure. That is, in the image forming apparatus of this embodiment, power is supplied to the heater from the power supply control means via the power supply means provided on the back side of the heating element installation portion.

[0062] Comparing the heater holder unit of this embodiment with the heater holder unit of the comparative example described above, which has a conventional configuration, the heater holder unit of this embodiment is approximately 13 mm smaller in the longitudinal direction. In other words, by bending the substrate so that the electrode installation part is parallel to the heating element installation part rather than perpendicular to it, and connecting it to the power supply means located on the back side of the heating element installation part, the heater holder unit of this embodiment is further reduced in the longitudinal direction compared to Example 1. This provides space-saving effects.

[0063] Example 4 Next, a fourth embodiment of the present invention will be described. The fourth embodiment is different from the first embodiment in the method of supplying power to the heater. Of the configuration of the fourth embodiment, the same components as those of the first embodiment are denoted by the same reference numerals and will not be described. Below, the characteristic configuration of the fourth embodiment will be described with reference to FIG. 14.

[0064] FIG. 14 is a schematic diagram showing a configuration for supplying power to the heater 22 held by the heater holder 81 of this embodiment. The heater 22 of this embodiment has a bent portion 221c, as in the first embodiment. The electrode installation portion 221b, on which the power supply electrode 226 of the heater 22 is provided, is provided at one end of the heater holder unit 80 in the longitudinal direction. A power supply connector 27 is connected to the electrode installation portion 221b of this embodiment. In the fixing device of this embodiment, since the substrate 221 is bent, the power supply connector 27 is attached in a state rotated 90° compared to the conventional configuration (see FIG. 9). Power is supplied to the heater 22 by connecting a power supply contact in the power supply connector 27, which serves as a power supply means, to the power supply electrode 226.

[0065] Comparing the heater holder unit of this embodiment with the heater holder unit of the comparative example, which has a conventional configuration, the heater holder unit of this embodiment is approximately 3 mm smaller in the longitudinal direction. In other words, by configuring the power supply connector so that it can be connected to the heater by rotating it 90 degrees, a space-saving effect in the longitudinal direction is achieved. This embodiment is particularly effective in configurations where the power supply connector has a large difference in width between the vertical and horizontal directions.

[0066] <Modification> In the above-described embodiments, the present invention has been described using a monochrome image forming apparatus. As mentioned at the beginning, the present invention can also be applied to various other devices. Examples of other image forming devices to which the present invention can be applied include a tandem color image forming device using a recording material transport belt, a four-cycle color image forming device using an intermediate transfer system, and a tandem color image forming device using an intermediate transfer system. Further examples include a color image forming device using a recording material transport belt in an intermediate transfer system, and an image forming device using four or more toners. Similar effects can be obtained by applying the present invention to the above-mentioned image forming devices.

[0067] Furthermore, in the above-described embodiments, a tensionless film heating method having a heater on the inner surface of the film has been described, but the present invention can also be applied to other methods. Examples of other methods include a fixing device having a heating roller that heats the toner image on the recording material and a film assembly unit that is pressed against the heating roller. Similar effects can be obtained by applying the present invention to fixing devices using the above-described configuration.

[0068] Other examples of modifications include a configuration in which the heating element is provided on the opposite surface of the heater rather than on the film contact surface side. The layer configuration of the heater can be modified in various ways depending on the application, size, etc. of the device, and the same effects can be obtained by applying the present invention to such configurations as well.

[0069] Other examples of modified examples include those in which the shape of the substrate is changed, such as by bending the substrate more gently. FIG. 15 is a schematic perspective view showing a heater 92 in which the substrate is bent more gently than in Example 1 (see FIG. 6). FIG. 16 is a schematic perspective view showing a heater 102 in which the substrate is bent more gently than in Example 3 (see FIG. 11). Each substrate 921, 1021 has a heating element mounting portion 921a, 1021a, an electrode mounting portion 921b, 1021b, and a bending portion 921c, 1021c. Since the configuration is the same as that of the above-described examples except for the shape of the bending portion, a description thereof will be omitted. Similar effects can be obtained by applying the present invention to such a configuration having a bending portion that is gently bent or a configuration in which a bending portion that is steep and a bending portion are combined.

[0070] Another example of a modified example is a configuration in which the power supply means and the power supply electrode are connected by welding. Fig. 17 is a schematic perspective view showing a modified example of the fourth embodiment (see Fig. 14) in which a power supply contact 87 is welded to the electrode installation portion 221b of the heater instead of a power supply connector. The other configurations are the same as those of the fourth embodiment, and therefore a description thereof will be omitted. In this way, the power supply means is not limited to those employed in the embodiments, and various modifications are possible, and similar effects can be obtained by applying the present invention to such configurations as well. [Explanation of symbols]

[0071] 22... heater, 221... substrate, 221a... heating element mounting portion, 221b... electrode mounting portion, 223... heating element, 226... power supply electrode

Claims

1. A heating element; an electrode for supplying power to the heating element; an elongated substrate on which the heating element and the electrodes are provided; In a heater comprising: The substrate is a heating element installation section having a plane on which the heating element is provided and extending in the longitudinal direction; an electrode installation portion bent from one end of the heat generating element installation portion in the longitudinal direction; and the heating element is disposed in the heating element mounting portion, and the electrodes are disposed in the electrode mounting portion; The heater is characterized in that the electrode installation portion extends parallel to the plane.

2. 2. The heater according to claim 1, further comprising a conductor that electrically connects the heating element and the electrode and extends from the heating element mounting portion to the electrode mounting portion.

3. 3. The heater according to claim 1, wherein the substrate is formed by bending a plate whose main material is metal.

4. a first rotating body; a heater according to any one of claims 1 to 3, which is provided in an internal space of the first rotating body; a second rotating body that forms a nip portion with the heating element installation portion of the heater via the first rotating body; A heating device comprising:

5. The heating device according to claim 4 , wherein the electrode installation portion is located farther from the nip portion than the heat generating element installation portion in the thickness direction of the heat generating element installation portion.

6. 6. The heating device according to claim 5, wherein the heat generating element is provided on a surface of the substrate facing the second rotating body in the thickness direction.

7. the first rotating body is a cylindrical film, 7. The method according to claim 4, wherein the second rotating body is a roller. Heating device included.

8. a heater holder that holds the heater and guides the rotation of the first rotating body, 8. The heating device according to claim 4, wherein the heater holder is provided with a power supply means for supplying power to the electrodes.

9. the power supply means is provided within the heater holder; 9. The heating device according to claim 8, wherein the heater holder includes a holding portion into which a portion of the heater including the electrodes is inserted and which holds the heater.

10. A first rotating body; a heater including a heating element, an electrode for supplying power to the heating element, and an elongated substrate on which the heating element and the electrode are provided, the heater being provided in the internal space of the first rotating body; a second rotating body that forms a nip portion with the heater via the first rotating body; a heater holder that holds the heater and guides the rotation of the first rotating body; Equipped with The substrate is a heating element installation portion extending in a longitudinal direction and forming the nip portion together with the second rotating body; an electrode installation portion bent from one end of the heat generating element installation portion in the longitudinal direction; and the heating element is disposed in the heating element mounting portion, and the electrodes are disposed in the electrode mounting portion; The heating device is characterized in that the heater holder is provided with a power supply means for supplying power to the electrodes.

11. A heating device as described in Claim 10, characterized in that the heater further comprises a conductor that electrically connects the heating element and the electrode and extends from the heating element installation portion to the electrode installation portion.

12. A heater as described in claim 10 or 11, characterized in that the substrate is formed by bending a plate made primarily of metal.

13. an image forming section for forming an image on a recording material; a heating device according to any one of claims 4 to 12, which fixes an image formed on a recording material to the recording material; An image forming apparatus having the same.

14. an image forming section for forming an image on a recording material; a heating device according to any one of claims 4 to 7, which fixes an image formed on a recording material to the recording material; a housing in which the image forming unit and the heating device are provided; An image forming apparatus having: an electric power supply means for supplying electric power to the electrodes is provided on the surface of the housing facing the heater at the one end side of the substrate in the longitudinal direction;

15. An image forming unit that forms an image on a recording material; a heating device for fixing an image formed on a recording material to the recording material; a housing in which the image forming unit and the heating device are provided; An image forming apparatus having: The heating device is a first rotating body; a heater including a heating element, an electrode for supplying power to the heating element, and an elongated substrate on which the heating element and the electrode are provided, the heater being provided in the internal space of the first rotating body; a second rotating body that forms a nip portion with the heater via the first rotating body; Equipped with The substrate is a heating element installation portion extending in a longitudinal direction and forming the nip portion together with the second rotating body; an electrode installation portion bent from one end of the heat generating element installation portion in the longitudinal direction; and the heating element is disposed in the heating element mounting portion, and the electrodes are disposed in the electrode mounting portion; an electric power supply means for supplying electric power to the electrodes is provided on the surface of the housing facing the heater at the one end side of the substrate in the longitudinal direction;

16. An image forming apparatus as described in Claim 15, characterized in that the heater further comprises a conductor that electrically connects the heating element and the electrode and extends from the heating element installation portion to the electrode installation portion.

17. An image forming apparatus as described in Claim 15 or 16, characterized in that the substrate is formed by bending a plate whose main material is metal.

18. An image forming apparatus described in any one of claims 15 to 17, characterized in that the electrode installation portion is located on a side farther away from the nip portion than the heating element installation portion in the thickness direction of the heating element installation portion.

19. An image forming apparatus as described in Claim 18, characterized in that the heating element is provided on a surface of the substrate facing the second rotating body in the thickness direction.

20. The first rotating body is a cylindrical film, 20. The image forming apparatus according to claim 15, wherein the second rotating body is a roller.

21. A heater holder for holding a heater including a heating element, an electrode for supplying power to the heating element, and an elongated substrate on which the heating element and the electrode are provided, a holding portion into which a part of the heater is inserted and which holds the heater; a power supply means provided in the holding portion and supplying power to the electrode; and The heater holder is characterized in that the power supply means is connected to electrodes provided on the heater inserted into the holding portion.

Images