Heater and image forming apparatus

Abstract

To provide a heater capable of suppressing warpage of a heater even if a substrate material is metal and an image forming apparatus.SOLUTION: A heater 1 includes a substrate 10 that includes metal and has a shape extending on one side, an insulating layer 11 provided on a first surface of the substrate, heating elements 21, 22 provided on the insulating layer and extending in the longitudinal direction of the substrate, a protective portion 40 covering the heating elements, and at least one convex part 10c provided along the peripheral part of a second surface of the substrate, opposing the first surface.SELECTED DRAWING: Figure 3

Description

【Technical Field】 【0001】 Embodiments of the present invention relate to a heater and an image forming apparatus. 【Background Art】 【0002】 Image forming apparatuses such as copiers and printers are provided with heaters for fixing toner. Generally, such a heater has a long substrate, a heating element provided on one surface of the substrate and extending in the longitudinal direction of the substrate, and a protective portion covering the heating element. 【0003】 The substrate is made of a material having heat resistance, insulation, and high thermal conductivity. The substrate is formed of, for example, ceramics such as aluminum oxide. Also, the substrate may be, for example, a metal plate whose surface is coated with an insulating material. The protective portion is made of a material having heat resistance, insulation, high thermal conductivity, and high chemical stability. For example, the protective portion is formed of ceramics, glass, or the like. 【0004】 Here, if the material of the substrate is metal, the rigidity of the substrate can be improved and the manufacturing cost can be reduced. However, if the material of the substrate is metal, the material of the substrate and the material of the protective portion will be different, so thermal stress will occur due to the difference in the thermal expansion coefficients of the materials. When thermal stress occurs, the heater is likely to warp. Furthermore, since the thermal expansion coefficient of metal is higher than that of ceramics or the like, the thermal stress is likely to increase. When the thermal stress increases, the warp of the heater increases. 【0005】 When the warp of the heater increases, the distance between the heater and the heating object varies, and there is a risk of uneven heating of the heating object. Therefore, even when the material of the substrate is metal, the development of a technology capable of suppressing the occurrence of warp in the heater has been desired. 【Prior Art Documents】 【Patent Documents】 【0006】 [Patent Document 1] Japanese Patent Publication No. 2007-240606 [Overview of the Initiative] [Problems that the invention aims to solve] 【0007】 The problem that this invention aims to solve is to provide a heater and an image forming apparatus that can suppress warping of the heater even when the substrate material is metal. [Means for solving the problem] 【0008】 The heater according to this embodiment includes a metal, First direction A substrate having a shape extending in the direction; an insulating layer provided on the first surface of the substrate; and provided on the insulating layer, First direction A heating element extending in that direction; a protective part covering the heating element; and a second surface of the substrate facing the first surface. , in a second direction perpendicular to the first direction Along the periphery The first extending Convex part and; A second protrusion extending along the periphery of the second surface of the substrate in the first direction; It is equipped with. At least one of the following is true: the distance between the top of the second protrusion and the second surface is shorter than the distance between the top of the first protrusion and the second surface, and the dimension of the second protrusion in the first direction is shorter than the dimension of the first protrusion in the second direction. [Effects of the Invention] 【0009】 According to embodiments of the present invention, it is possible to provide a heater and an image forming apparatus that can suppress warping of the heater even when the substrate material is metal. [Brief explanation of the drawing] 【0010】 [Figure 1] This is a schematic front view illustrating the heater according to this embodiment. [Figure 2] This is a schematic rear view illustrating a heater. [Figure 3] This is a schematic cross-sectional view of the heater in the direction of line AA in Figure 1. [Figure 4] Figure 1 is a schematic side view of the heater in the direction of line BB. [Figure 5]It is a schematic rear view for exemplifying a substrate according to another embodiment. [Figure 6] It is a schematic cross-sectional view for exemplifying a convex portion according to another embodiment. [Figure 7] It is a schematic enlarged view of part C in FIG. 6. [Figure 8] It is a schematic diagram for exemplifying an image forming apparatus according to the present embodiment. [Figure 9] It is a schematic diagram for exemplifying a fixing unit. 【Embodiments for Carrying Out the Invention】 【0011】 Hereinafter, embodiments will be exemplified while referring to the drawings. In each drawing, the same components are denoted by the same reference numerals, and detailed descriptions thereof are omitted as appropriate. Also, in each drawing, arrows X, Y, and Z represent three mutually orthogonal directions. For example, the longitudinal direction of the substrate is the X direction, the short side direction (width direction) of the substrate is the Y direction, and the direction perpendicular to the surface of the substrate is the Z direction. 【0012】 (Heater) FIG. 1 is a schematic front view for exemplifying the heater 1 according to the present embodiment. Note that FIG. 1 is a view of the heater 1 seen from the side where the heat generating portion 20 is provided. FIG. 2 is a schematic rear view for exemplifying the heater 1. Note that FIG. 2 is a view of the heater 1 seen from the side opposite to the side where the heat generating portion 20 is provided. FIG. 3 is a schematic cross-sectional view in the direction of line A - A of the heater 1 in FIG. 1. FIG. 4 is a schematic side view in the direction of line B - B of the heater 1 in FIG. 1. 【0013】 As shown in FIGS. 1 to 4, the heater 1 has, for example, a substrate 10, an insulating layer 11, a heat generating portion 20, a wiring portion 30, and a protection portion 40. 【0014】 The substrate 10 is plate-shaped and has a surface 10a (corresponding to an example of the first surface) and a surface 10b (corresponding to an example of the second surface) facing the surface 10a. The substrate 10 has a shape extending in the X direction. The shape of the substrate 10 viewed from the Z direction is, for example, a long rectangular shape. The thickness of the substrate 10 is, for example, about 0.5 mm to 1.0 mm. The dimensions of the substrate 10 in the X direction and the dimensions of the substrate 10 in the Y direction can be appropriately changed according to the size of the object to be heated (e.g., paper). 【0015】 The substrate 10 has heat resistance and is formed of a material with high thermal conductivity. The substrate 10 can be formed of, for example, a metal such as stainless steel or an aluminum alloy. 【0016】 The thermal conductivity of the metal is higher than that of inorganic materials such as ceramics. Therefore, if the substrate 10 is formed of a metal, it is possible to suppress the occurrence of an in-plane distribution in the temperature of the heater 1. In addition, it is possible to improve the rigidity of the substrate 10 and reduce the manufacturing cost. 【0017】 The insulating layer 11 is provided on the surface 10a of the substrate 10 on the side where the heat generating portion 20 is provided. The insulating layer 11 covers the region of the surface 10a of the substrate 10 where the heat generating portion 20 is provided. The insulating layer 11 is formed of a material having heat resistance and insulation properties. The insulating layer 11 can be formed of, for example, an inorganic material such as ceramics. 【0018】 The heat generating portion 20 converts the applied electric power into heat (Joule heat). The heat generating portion 20 is provided on the insulating layer 11. The heat generating portion 20 and the substrate 10 are insulated by the insulating layer 11. The heat generating portion 20 has, for example, a heating element 21 and a heating element 22. As an example, the case where the heating element 21 and the heating element 22 are provided is illustrated, but the number and size of the heating elements can be appropriately changed according to the size of the substrate 10 and the size of the object to be heated. In addition, a plurality of types of heating elements having different lengths, widths, shapes, etc. can also be provided. That is, at least one heating element may be provided. 【0019】 The heating elements 21 and 22 can be arranged side by side at a predetermined interval in the Y direction (the short side direction of the substrate 10). The heating elements 21 and 22 extend in the X direction (the long side direction of the substrate 10), for example. 【0020】 The dimensions (length dimensions) of heating elements 21 and 22 in the X direction can be, for example, approximately the same. In this case, it is preferable that the centers of heating elements 21 and 22 are located on the straight line 1a. That is, it is preferable that heating elements 21 and 22 each have a shape that is symmetrical with respect to the straight line 1a as the axis of symmetry. 【0021】 When attaching the heater 1 to the image forming apparatus 100, for example, the straight line 1a is aligned with the center line of the transport path of the object to be heated. In this way, even if the dimensions of the object to be heated change in a direction perpendicular to the transport direction, the object to be heated can be heated substantially uniformly. 【0022】 The electrical resistance values ​​of heating elements 21 and 22 can be approximately the same or different. For example, by making the dimensions in the X direction (length), Y direction (width), and Z direction (thickness) of heating elements 21 and 22 approximately the same, the electrical resistance values ​​of heating elements 21 and 22 can be made approximately the same. Alternatively, by changing at least one of these dimensions, the electrical resistance values ​​of heating elements 21 and 22 can be made different. Furthermore, by changing the material, the electrical resistance values ​​of heating elements 21 and 22 can be made different. 【0023】 Furthermore, the electrical resistance per unit length of the heating element 21 can be made approximately uniform in the X direction. For example, the dimensions of the heating element 21 in the Y direction (width dimension) and the Z direction (thickness dimension) can be made approximately constant. The shape of the heating element 21 as viewed from the Z direction can be, for example, an approximately rectangular shape extending in the X direction. 【0024】 Furthermore, the electrical resistance per unit length of the heating element 22 can be made approximately uniform in the X direction. For example, the dimensions of the heating element 22 in the Y direction (width dimension) and the Z direction (thickness dimension) can be made approximately constant. The shape of the heating element 22 as viewed from the Z direction can be, for example, an approximately rectangular shape extending in the X direction. 【0025】 The heating elements 21 and 22 can be formed using, for example, ruthenium oxide (RuO2), silver-palladium (Ag-Pd) alloy, etc. The heating elements 21 and 22 can be formed by, for example, applying a paste-like material onto the insulating layer 11 using a screen printing method, and then curing it using a firing method, etc. 【0026】 The wiring section 30 is provided on top of the insulating layer 11. The wiring section 30 includes, for example, terminals 31, terminals 32, wiring 33, wiring 34, and wiring 35. 【0027】 Terminals 31 and 32 are provided, for example, near one end of the substrate 10 in the X direction. Terminals 31 and 32 are provided, for example, side by side in the X direction. Terminals 31 and 32 are electrically connected to, for example, a power supply, via connectors and wiring. 【0028】 The wiring 33 is provided, for example, on the side of the substrate 10 where the terminal 31 is located, in the X direction. The wiring 33 extends in the X direction. The wiring 33 is electrically connected to the terminal 31 and to the terminal 31 side end of the heating element 21. 【0029】 The wiring 34 is provided, for example, near the end of the substrate 10 opposite to the side where terminals 31 and 32 are provided, in the X direction. The end of the heating element 21 opposite to the wiring 33, and the end of the heating element 22 opposite to the wiring 35 are electrically connected to the wiring 34. 【0030】 The wiring 35 is provided, for example, on the side of the substrate 10 where the terminal 32 is located, in the X direction. The wiring 35 extends in the X direction. The wiring 35 is electrically connected to the terminal 32 and to the terminal 32 side end of the heating element 22. 【0031】 The wiring section 30 (terminals 31, 32 and wiring 33-35) is formed using a material containing, for example, silver or copper. For example, terminals 31, 32 and wiring 33-35 can be formed by applying a paste-like material onto the insulating layer 11 using a screen printing method or the like, and then curing it using a firing method or the like. 【0032】 The protective section 40 is provided on the insulating layer 11 and covers the heating section 20 (heating elements 21 and 22) and a portion of the wiring section 30 (wiring 33, wiring 34, and wiring 35). In this case, terminals 31 and 32 of the wiring section 30 are exposed from the protective section 40. 【0033】 The protective part 40 extends in the X direction. The protective part 40 has the function of insulating the heat-generating part 20 and a portion of the wiring part 30, transferring heat generated in the heat-generating part 20, and protecting the heat-generating part 20 and a portion of the wiring part 30 from external forces, corrosive gases, etc. The protective part 40 is made of a material that has heat resistance and insulation properties, and high chemical stability and thermal conductivity. The protective part 40 is made of, for example, ceramics or glass. In this case, the protective part 40 can also be made using glass to which a filler containing a material with high thermal conductivity, such as aluminum oxide, has been added. The thermal conductivity of the glass to which the filler has been added can be, for example, 2 [W / (m·K)] or more. 【0034】 Furthermore, the heater 1 may be further provided with a detection unit for detecting the temperature of the heat-generating section 20. The detection unit may be, for example, a thermistor. The detection unit may be provided on at least one of the sides of the substrate 10 where the heat-generating section 20 is provided, and on the side of the substrate 10 opposite to the side where the heat-generating section 20 is provided. 【0035】 If the detection unit is provided on the side of the substrate 10 where the heat-generating unit 20 is provided (the side of the substrate 10 surface 10a), the detection unit and the wiring and terminals electrically connected to the detection unit can be provided on the insulating layer 11. The wiring electrically connected to the detection unit can be covered by the protective unit 40. The terminals electrically connected to the detection unit can be exposed from the protective unit 40. 【0036】 If the detection unit is located on the side of the substrate 10 opposite to the side where the heating element 20 is located (the side of surface 10b of the substrate 10), an insulating layer can be provided on surface 10b, and the detection unit, as well as the wiring and terminals electrically connected to the detection unit, can be provided on the insulating layer. The insulating layer can be the same as the insulating layer 11 provided on surface 10a. In addition, the wiring electrically connected to the detection unit can be covered by a protective part. The terminals electrically connected to the detection unit can be exposed from the protective part. The protective part can be the same as the protective part 40 provided on the insulating layer 11. 【0037】 As mentioned above, the substrate 10 is formed from a metal such as stainless steel or an aluminum alloy. On the other hand, the protective part 40 is formed from, for example, ceramics, glass, or glass with fillers added. The insulating layer 11 is formed from, for example, an inorganic material such as ceramics. 【0038】 Therefore, the thermal expansion coefficient of the substrate 10 differs from that of the protective part 40 and the insulating layer 11. Also, when the heater 1 is used and the heating element 20 (heating elements 21 and 22) is heated, the substrate 10, the protective part 40, and the insulating layer 11 are heated. When the protective part 40 and the insulating layer 11 are fired during the manufacturing of the heater 1, the substrate 10, the protective part 40, and the insulating layer 11 are heated. Therefore, thermal stress is generated during the use and manufacturing of the heater 1 due to the difference in the thermal expansion coefficients of the materials. When thermal stress occurs, there is a risk that the heater 1 may warp. 【0039】 Furthermore, since the thermal expansion coefficient of metals is higher than that of ceramics, the heater 1 is more prone to warping. Also, if the length of the substrate 10 in the short direction (width direction: for example, the Y direction) is short, or if the length of the substrate 10 in the long direction (for example, the X direction) is long, or if the thickness of the substrate 10 is thin, the heater 1 is more prone to warping. If the warping of heater 1 becomes excessive, the distance between heater 1 and the object to be heated will vary, which may cause uneven heating of the object. 【0040】 As shown in Figures 2 to 4, the substrate 10 is provided with protrusions 10c and 10d. The protrusions 10c and 10d are provided on the side of the substrate 10 opposite to the side where the heating element 20 is provided. The protrusions 10c and 10d protrude from the surface 10b of the substrate 10. The protrusions 10c and 10d can be formed integrally with the substrate 10, for example. The protrusions 10c and 10d can be formed by, for example, press molding or bending. 【0041】 The protrusion 10c is provided along the periphery of the surface 10b of the substrate 10 in the Y direction. The protrusion 10c extends between one end and the other end of the substrate 10 in the X direction. The distance H (height of the protrusion 10c) between the top of the protrusion 10c and the surface 10b of the substrate 10 can be, for example, about 0.3 mm to 5.0 mm. The thickness T of the protrusion 10c can be, for example, about 0.3 mm to 1.0 mm. 【0042】 The protrusion 10d is provided along the periphery of the surface 10b of the substrate 10 in the X direction. The protrusion 10d extends in the Y direction. As shown in Figures 2 and 4, a gap can be provided between the protrusion 10d and the protrusion 10c. Alternatively, the protrusion 10d and the protrusion 10c can be in contact. The distance between the top of the protrusion 10d and the surface 10b of the substrate 10 (the height of the protrusion 10d) can be the same as or different from the distance H between the top of the protrusion 10c and the surface 10b of the substrate 10. The thickness of the protrusion 10d can be the same as, for example, the thickness T of the protrusion 10c, or different. 【0043】 If protrusions 10c and 10d are provided, the bending rigidity of the substrate 10 can be increased. If the bending rigidity of the substrate 10 is increased, even if thermal stress is generated due to the difference in thermal expansion coefficients of the materials, warping of the heater 1 can be suppressed. 【0044】 The protrusions 10c illustrated in Figures 2 to 4 are provided on both ends of the substrate 10 in the Y direction. However, if the generated thermal stress is small or the length of the substrate 10 in the X direction is short, the resulting warping will be small. When the resulting warping is small, it is possible to provide the protrusions 10c on one end of the substrate 10 in the Y direction and not on the other end of the substrate 10. By providing the protrusions 10c only on one end of the substrate 10, the manufacturing cost of the heater 1 can be reduced. 【0045】 Furthermore, while we have illustrated the case where a single protrusion 10c is provided at the edge of the substrate 10 in the Y direction, extending continuously in the X direction, it is also possible to provide a protrusion 10c in a part of the substrate 10 in the X direction, or to provide multiple protrusions 10c aligned in the X direction. 【0046】 The protrusions 10d illustrated in Figures 2 to 4 are provided on both ends of the substrate 10 in the X direction. However, if the generated thermal stress is small or the length of the substrate 10 in the Y direction is short, the resulting warping will be small. When the resulting warping is small, it is possible to provide the protrusions 10d on one end of the substrate 10 in the X direction and not on the other end of the substrate 10. By providing the protrusions 10d only on one end of the substrate 10, the manufacturing cost of the heater 1 can be reduced. 【0047】 Furthermore, while we have illustrated the case where a single protrusion 10d extending continuously in the Y direction is provided at the edge of the substrate 10 in the X direction, it is also possible to provide a protrusion 10d in a part of the substrate 10 in the Y direction, or to provide multiple protrusions 10d aligned in the Y direction. 【0048】 Furthermore, the length of the substrate 10 in the X direction is longer than the length of the substrate 10 in the Y direction. Therefore, the warp of the substrate 10 in the X direction is greater than the warp of the substrate 10 in the Y direction. In this case, the height of the protrusion 10c can be made greater than the height of the protrusion 10d. The thickness of the protrusion 10c can also be made greater than the thickness of the protrusion 10d. By doing so, it is possible to suppress the warping of the substrate 10 in the X direction. 【0049】 Figure 5 is a schematic rear view illustrating a substrate 10e according to another embodiment. Figure 5 shows the substrate 10e viewed from the side opposite to the side where the heat-generating section 20 is located. The length of the substrate 10e in the Y direction is shorter than the length of the substrate 10e in the X direction. Therefore, the curvature of the substrate 10e in the Y direction is smaller than the curvature of the substrate 10e in the X direction. 【0050】 In such cases, as shown in Figure 5, a protrusion 10c can be provided at the end of the substrate 10e in the Y direction, while a protrusion 10d can not be provided at the end of the substrate 10e in the X direction. Furthermore, if the warping of the substrate 10e is small, a protrusion 10c can be provided at one end of the substrate 10e in the Y direction, while a protrusion 10c can not be provided at the other end of the substrate 10e. By doing so, the manufacturing cost of heater 1 can be reduced. 【0051】 Figure 6 is a schematic cross-sectional view illustrating a protrusion 10c1 according to another embodiment. Figure 7 is a schematic enlarged view of section C in Figure 6. The protrusions 10c illustrated in Figures 3 and 4 are perpendicular to the surface 10b of the substrate 10. In contrast, the protrusions 10c1 illustrated in Figures 6 and 7 are inclined with respect to the surface 10b of the substrate 10. For example, the protrusion 10c1 can be a tilted protrusion 10c. The inclination angle θ between the protrusion 10c1 and the surface 10b of the substrate 10 can be, for example, "90° < θ ≤ 160°". Alternatively, the inclination angle θ between the protrusion 10c1 and the surface 10b of the substrate 10 can be, for example, "20° ≤ θ < 90°". 【0052】 If the protrusion 10c1 is inclined with respect to the surface 10b of the substrate 10, the bending rigidity of the substrate 10 can be improved, and the size of the heater 1 in the Z direction can be suppressed. Also, if "20°≦θ<90°", when viewed from the Z direction, the tip of the protrusion 10c1 is located inside the surface 10b of the substrate 10, so the bending rigidity of the substrate 10 can be improved, and the size of the heater 1 in the Z and Y directions can be suppressed. 【0053】 The arrangement, number, dimensions, and inclination angle θ of the protrusions 10c and 10d can be appropriately changed depending on the amount of thermal stress and warping that occurs. The arrangement, number, dimensions, and inclination angle θ of the protrusions 10c and 10d can be appropriately determined, for example, by conducting experiments or simulations. 【0054】 (Image forming apparatus) In one embodiment of the present invention, an image forming apparatus 100 equipped with a heater 1 can be provided. The above-described heater 1 and its variations (for example, the arrangement, number, dimensions, and inclination angle θ of the convex portions 10c and 10d described above) can all be applied to the image forming apparatus 100. 【0055】 Furthermore, in the following section, we will explain the case where the image forming apparatus 100 is a copier as an example. However, the image forming apparatus 100 is not limited to a copier; it can be any apparatus that has a heater for fixing the toner. For example, the image forming apparatus 100 can be a printer or the like. 【0056】 Figure 8 is a schematic diagram illustrating the image forming apparatus 100 according to this embodiment. Figure 9 is a schematic diagram illustrating the fixing section 200. As shown in Figure 8, the image forming apparatus 100 includes, for example, a frame 110, an illumination unit 120, an imaging element 130, a photosensitive drum 140, a charging unit 150, a discharge unit 151, a developing unit 160, a cleaner 170, a storage unit 180, a transport unit 190, a fixing unit 200, and a controller 210. 【0057】 The frame 110 is box-shaped and houses the illumination unit 120, the imaging element 130, the photosensitive drum 140, the charging unit 150, the developing unit 160, the cleaner 170, part of the storage unit 180, the transport unit 190, the fixing unit 200, and the controller 210 inside. A window 111 made of a light-transmitting material such as glass can be provided on the top surface of the frame 110. The original document 500 to be copied is placed on top of the window 111. A movable part for moving the position of the original document 500 can also be provided. 【0058】 The lighting unit 120 is provided near the window 111. The lighting unit 120 includes, for example, a light source 121 such as a lamp, and a reflector 122. The imaging element 130 is provided near the window 111. The photosensitive drum 140 is located below the illumination unit 120 and the imaging element 130. The photosensitive drum 140 is rotatably mounted. The surface of the photosensitive drum 140 is provided with, for example, a zinc oxide photosensitive layer or an organic semiconductor photosensitive layer. The charging unit 150, the discharge unit 151, the developing unit 160, and the cleaner 170 are located around the photosensitive drum 140. 【0059】 The storage unit 180 includes, for example, a cassette 181 and a tray 182. The cassette 181 is detachably attached to one side of the frame 110. The tray 182 is located on the side of the frame 110 opposite to the side to which the cassette 181 is attached. The cassette 181 holds paper 510 (for example, blank paper) before copying. The tray 182 holds paper 511 on which the copied image 511a has been fixed. 【0060】 The transport unit 190 is located below the photosensitive drum 140. The transport unit 190 transports the paper 510 between the cassette 181 and the tray 182. The transport unit 190 includes, for example, a guide 191 that supports the paper 510 being transported, and transport rollers 192 to 194 that transport the paper 510. The transport unit 190 may also be equipped with a motor to rotate the transport rollers 192 to 194. 【0061】 The fixing unit 200 is located downstream of the photosensitive drum 140 (on the tray 182 side). As shown in Figure 9, the fixing unit 200 includes, for example, a heater 1, a stay 201, a film belt 202, and a pressure roller 203. A heater 1 is attached to the stay 201 on the side facing the paper 510 transport line. The heater 1 can be embedded in the stay 201. In this case, the side of the heater 1 with the protective part 40 is exposed from the stay 201. 【0062】 The film belt 202 covers the stay 201 on which the heater 1 is provided. The film belt 202 may include a heat-resistant resin such as polyimide. 【0063】 The pressure roller 203 is positioned opposite the stay 201. The pressure roller 203 includes, for example, a core metal 203a, a drive shaft 203b, and an elastic part 203c. The drive shaft 203b protrudes from the end of the core metal 203a and is connected to a drive device such as a motor. The elastic part 203c is provided on the outer surface of the core metal 203a. The elastic part 203c is formed from a heat-resistant elastic material. The elastic part 203c may include, for example, silicone resin. 【0064】 The controller 210 is located inside the frame 110. The controller 210 includes, for example, a processing unit such as a CPU (Central Processing Unit) and a storage unit that stores a control program. The processing unit controls the operation of each element provided in the image forming apparatus 100 based on the control program stored in the storage unit. The controller 210 may also include an operation unit for the user to input copying conditions, a display unit to display the operating status and error indications, etc. Since known techniques can be applied to the control of each element provided in the image forming apparatus 100, a detailed explanation will be omitted. 【0065】 Although several embodiments of the present invention have been illustrated above, these embodiments are presented as examples only and are not intended to limit the scope of the invention. These novel embodiments can be implemented in various other forms, and various omissions, substitutions, and modifications can be made without departing from the spirit of the invention. These embodiments and their variations are included in the scope and spirit of the invention, as well as in the claims of the invention and its equivalents. Furthermore, the embodiments described above can be implemented in combination with each other. 【0066】 The following are additional notes regarding the embodiments described above. 【0067】 (Note 1) A substrate containing metal and having a shape extending in one direction; An insulating layer provided on the first surface of the substrate; A heating element provided on the insulating layer and extending in the longitudinal direction of the substrate; A protective part covering the aforementioned heating element; The substrate has at least one protrusion provided along the periphery of the second surface facing the first surface; A heater equipped with [a certain feature]. 【0068】 (Note 2) The aforementioned protrusion is the heater described in Appendix 1, which extends in the longitudinal direction of the substrate. 【0069】 (Note 3) The heater described in Appendix 1 or 2 satisfies the following equation when the inclination angle between the convex portion and the second surface is θ. 90° < θ ≤ 160°, or 20° ≤ θ < 90° 【0070】 (Note 4) The aforementioned protrusion is a heater according to any one of the appendices 1 to 3, which is formed integrally with the substrate. 【0071】 (Note 5) An image forming apparatus equipped with a heater as described in any one of the appendices 1 to 4. [Explanation of symbols] 【0072】 1 Heater, 10 Substrate, 10a surface, 10b surface, 10c protrusion, 10c1 protrusion, 10d protrusion, 10e Substrate, 11 Insulating layer, 20 Heating section, 21 Heating element, 22 Heating element, 30 Wiring section, 40 Protection section, 100 Image forming apparatus, 200 Fixing section, θ Tilt angle

Claims

[Claim 1] A substrate containing metal and having a shape extending in a first direction; An insulating layer provided on the first surface of the substrate; A heating element provided on the insulating layer and extending in the first direction; A protective part covering the heating element; A first protrusion extending along the periphery of the second surface of the substrate facing the first surface in a second direction perpendicular to the first direction; A second protrusion extending along the periphery of the second surface of the substrate in the first direction; It is equipped with, The distance between the top of the second convex portion and the second surface is shorter than the distance between the top of the first convex portion and the second surface. And, The dimension of the second protrusion in the first direction is shorter than the dimension of the first protrusion in the second direction. A heater that is at least one of the following. [Claim 2] A gap is provided between the first protrusion and the second protrusion. or The heater according to claim 1, wherein the first protrusion and the second protrusion are in contact. [Claim 3] The heater according to claim 1 or 2, wherein the following equation is satisfied when the inclination angle between the first protrusion and the second surface is θ. 90° < θ ≤ 160°, or 20° ≤ θ < 90° [Claim 4] The heater according to claim 1 or 2, wherein the first protrusion and the second protrusion are integrally formed with the substrate. [Claim 5] An image forming apparatus comprising the heater described in claim 1.

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