Heater and image forming apparatus

Abstract

To provide a heater that can provide parts to perform electrical connection with the outside and detection parts on a side of a substrate opposite to a side provided with a heating element with a simple configuration, and an image forming apparatus.SOLUTION: A heater according to an embodiment is provided with: a substrate that extends in one direction; a first insulating part that is provided on a first surface of the substrate and has insulating properties; a heating element that is provided on the first insulating part and extends in a longitudinal direction of the substrate; terminals that are provided on both ends of the substrate and exhibit a plate shape; joint parts that are each provided between each of the ends of the substrate and each of the terminals and have insulating properties; a second insulating part that is provided on a second surface opposite to the first surface and has insulating properties; and detection parts that are provided on the second insulating part and detect a temperature. A surface of the terminal on the side opposite to the side provided with the heating element is exposed from the second insulating part.SELECTED DRAWING: Figure 2

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 a heater for fixing toner. In addition, heaters are also provided in printing erasure devices provided in rewritable card readers and writers. 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 pair of terminals provided on the surface of the substrate where the heating element is provided and electrically connected to the heating element. A power source, a control circuit, etc. are electrically connected to the pair of terminals via a harness (for example, a connector and wiring). That is, in a general heater, the heating element and the portion for making an electrical connection to the outside are provided on the same side of the substrate.

[0003] However, depending on the use of the heater, it may be preferable that the portion for making an electrical connection to the outside is provided on the side of the substrate opposite to the side where the heating element is provided. For example, in some cases, it may be preferable to provide a portion for making an electrical connection to the outside on the side of the substrate facing the object to be heated (for example, paper) (the sliding surface side), and to provide the heating element on the side of the substrate opposite to the side of the object to be heated (the non-sliding surface side).

[0004] In this case, the heating element and the portion for making an electrical connection to the outside can be electrically connected via a conductive member penetrating the thickness direction of the substrate. However, if this is done, the strength of the substrate will be reduced, so there is a risk that the substrate will be deformed or damaged due to thermal stress generated during use of the heater. In addition, since the dimension in the short side direction (width dimension) of the substrate increases, it becomes difficult to miniaturize the heater.

[0005] Furthermore, in order to control the temperature of the heater, a detection unit such as a thermistor may be provided on the substrate. In this case, depending on the use of the heater, it may be preferable for the detection unit to be provided on the side of the substrate opposite to the side where the heating element is provided.

[0006] Therefore, the development of a technology that can provide a simple configuration and can provide a part for making electrical connection with the outside and a detection unit on the side of the substrate opposite to the side where the heating element is provided has been desired.

Prior Art Documents

Patent Documents

[0007]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0008] The problem to be solved by the present invention is to provide a heater and an image forming apparatus that can provide a simple configuration and can provide a part for making electrical connection with the outside and a detection unit on the side of the substrate opposite to the side where the heating element is provided.

Means for Solving the Problems

[0009] The heater according to the embodiment includes a substrate that contains metal, has a plate shape, and extends in one direction; a first insulating portion provided on the first surface of the substrate and having insulation properties; a heating element provided on the first insulating portion and extending in the longitudinal direction of the substrate; terminals provided at both ends of the substrate in the longitudinal direction of the substrate, having conductivity, and having a plate shape; a first wiring provided on the first insulating portion and electrically connected to the heating element and the terminals having conductivity; a joint portion provided between the end of the substrate and the terminal and having insulation properties; a second insulating portion provided on the second surface of the substrate facing the first surface and having insulation properties; and at least one detection portion provided on the second insulating portion and detecting temperature. The surface of the terminal on the side opposite to the side where the heating element is provided is exposed from the second insulating portion.

Advantages of the Invention

[0010] According to the embodiment of the present invention, it is possible to provide a heater and an image forming apparatus that can be provided with a portion for making an electrical connection with the outside and a detection portion on the side of the substrate opposite to the side where the heating element is provided with a simple configuration.

Brief Description of the Drawings

[0011]

Figure 1

Figure 2

Figure 3

Figure 4

Figure 5

Figure 6

Figure 7

Embodiment for Carrying Out the Invention

[0012] Hereinafter, embodiments will be exemplified with reference 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, the arrows X, Y, and Z in each drawing 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 plane of the substrate is the Z direction.

[0013] (Heater) FIG. 1 is a schematic view of the heater 1 according to the present embodiment as viewed from one side in the Z direction. FIG. 2 is a schematic view of the heater 1 as viewed from the other side in the Z direction. FIG. 3 is a schematic cross-sectional view of the heater 1 in the direction of line A-A in FIG. 1. FIG. 4 is a schematic cross-sectional view of the heater 1 in the direction of line B-B in FIG. 1. FIG. 5 is a schematic cross-sectional view of the heater 1 in the direction of line C-C in FIG. 1.

[0014] As shown in FIGS. 1 to 5, the heater 1 includes, for example, a substrate 10, an insulating portion 21 (corresponding to an example of a first insulating portion), an insulating portion 22 (corresponding to an example of a second insulating portion), a heating element 30, a wiring 40 (corresponding to an example of a first wiring), a protection portion 51 (corresponding to an example of a first protection portion), a protection portion 52 (corresponding to an example of a second protection portion), a terminal 60, a joining portion 70, a detection portion 80, and a wiring 81 (corresponding to an example of a second wiring). The insulating portion 21, the heating element 30, the wiring 40, and the protection portion 51 are provided on one surface 10a side of the substrate 10 in the Z direction. The insulating portion 22, the detection portion 80, the wiring 81, and the protection portion 52 are provided on the other surface 10b side of the substrate 10 in the Z direction.

[0015] 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 one direction (for example, the X direction). The planar shape of the substrate 10 is, for example, a long rectangle. The thickness of the substrate 10 is, for example, about 0.5 mm to 1.0 mm. The width dimension (dimension in the short side direction; dimension in the Y direction) of the substrate 10 is, for example, about 5 mm to 15 mm. The length (dimension in the long side direction; dimension in the X direction) of the substrate 10 can be appropriately changed according to the size of the object to be heated (for example, paper).

[0016] The substrate 10 has heat resistance and is formed of a material with high thermal conductivity. Generally, the substrate is formed of ceramics such as aluminum oxide, but in the heater 1 according to the present embodiment, a substrate 10 containing a metal is provided. The metal can be, for example, stainless steel, an aluminum alloy, or the like.

[0017] As shown in FIGS. 1 and 5, the insulating portion 21 has insulating properties and is provided on the surface 10a of the substrate 10. The insulating portion 21 can be provided, for example, so as to cover the surface 10a of the substrate 10 and a part of the terminal 60. The insulating portion 21 is provided to insulate between the substrate 10 containing a metal, the heating element 30, and the wiring 40. Therefore, the insulating portion 21 is provided between the substrate 10, the heating element 30, and the wiring 40. The insulating portion 21 can be formed of an inorganic material such as ceramics or a glass material. The insulating portion 21 can be formed, for example, by thermal spraying or firing.

[0018] The heating element 30 converts the applied electric power into heat (Joule heat). The heating element 30 is provided on the insulating portion 21 (the surface on the side opposite to the substrate 10 side of the insulating portion 21). The heating element 30 extends, for example, in the X direction. One heating element 30 can be provided at the center of the substrate 10 in the Y direction.

[0019] The heating element 30 is, for example, ruthenium oxide (RuO 2) It can be formed using, for example, a silver-palladium (Ag-Pd) alloy. The heating element 30 can be formed, for example, by applying a paste-like material onto the insulating portion 21 using a screen printing method or the like and curing it using a firing method or the like.

[0020] The wiring 40 is provided, for example, on the insulating portion 21. The wiring 40 is electrically connected to the heating element 30 and the terminal 60. For example, one end of the wiring 40 is electrically connected to the heating element 30. For example, the other end of the wiring 40 is provided outside the insulating portion 21 in the X direction. The other end of the wiring 40 is provided on the terminal 60 and is electrically connected to the terminal 60. Note that holes, notches, or the like may be provided in the insulating portion 21, and the other end of the wiring 40 may be electrically connected to the terminal 60 through the holes, notches, or the like.

[0021] The wiring 40 is formed using, for example, a material containing silver, copper, or the like. For example, the wiring 40 can be formed by applying a paste-like material onto the insulating portion 21 using a screen printing method or the like and curing it using a firing method or the like.

[0022] The protection portion 51 is provided, for example, on the insulating portion 21, the heating element 30, and the wiring 40 and extends in the X direction. The protection portion 51 covers, for example, the heating element 30 and the wiring 40. The protection portion 51 has, for example, a function of insulating the heating element 30 and the wiring 40, a function of transmitting the heat generated in the heating element 30 to the outside, and a function of protecting the heating element 30 and the wiring 40 from external forces, corrosive gases, and the like. The protection portion 51 has heat resistance and insulation properties and is formed from a material having high chemical stability and thermal conductivity. The protection portion 51 is formed from, for example, an inorganic material such as ceramics or a glass material. In this case, the protection portion 51 can also be formed using a glass material to which a filler containing a material having high thermal conductivity such as aluminum oxide is added. The thermal conductivity of the glass material to which the filler is added can be, for example, 2 [W / (m·K)] or more.

[0023] The protective part 51 can be formed, for example, by applying a paste-like material onto the insulating part 21, the heating element 30, and the wiring 40 using a screen printing method or the like and curing it using a firing method or the like.

[0024] As shown in FIGS. 2 and 5, the insulating part 22 has insulation properties and is provided on the surface 10b of the substrate 10. The insulating part 22 can be provided, for example, so as to cover the surface 10b of the substrate 10.

[0025] The insulating part 22 is provided to insulate between the substrate 10 containing metal, the detection part 80, and the wiring 81. Therefore, the insulating part 22 is provided between the substrate 10, the detection part 80, and the wiring 81. The thickness and the forming method of the insulating part 22 can be the same as, for example, the thickness and the forming method of the aforementioned insulating part 21. Also, the material of the insulating part 22 may be the same as the material of the insulating part 21 or may be different from the material of the insulating part 21. For example, the material of the insulating part 22 may be a heat-resistant resin such as polyimide.

[0026] The detection part 80 is provided to control the temperature of the heater 1. The detection part 80 detects the temperature of the heater 1 (heating element 30). The detection part 80 can be, for example, a thermistor or the like. The detection part 80 is provided on the insulating part 22 (the surface on the side opposite to the substrate 10 side of the insulating part 22).

[0027] At least one detection part 80 can be provided. Two detection parts 80 are provided in the heater 1 illustrated in FIG. 2. In this case, if a plurality of detection parts 80 are provided, the temperature control of the heater 1 can be performed more precisely. For example, in the X direction, one detection part 80 can be provided at the center position of the heating element 30. The number, arrangement, etc. of the detection parts 80 are not limited to those illustrated in FIG. 2 and can be appropriately changed according to the size of the substrate 10, the number and size of the heating elements 30, etc.

[0028] A pair of wirings 81 are electrically connected to the detection unit 80. The pair of wirings 81 are provided on the upper side of the insulating part 22 (the surface on the side opposite to the substrate 10 side of the insulating part 22). The pair of wirings 81 extend in the X direction. One end of the wiring 81 is electrically connected to the detection unit 80. The other end of the wiring 81 is exposed from the protection part 52.

[0029] The detection unit 80 can be formed, for example, by applying a paste-like material to the ends of the pair of wirings 81 using a screen printing method or the like and curing it using a firing method or the like. When the detection unit 80 is a thermistor, the detection unit 80 can be formed, for example, using a material containing barium titanate, a material containing an oxide, or the like. The oxide can be, for example, an oxide of nickel, manganese, cobalt, iron, or the like. The material and formation method of the wiring 81 can be the same as those of the wiring 40 described above, for example.

[0030] The protection part 52 is provided, for example, on the insulating part 22, the detection unit 80, and the wiring 81 and extends in the X direction. The protection part 52 covers, for example, the detection unit 80 and the pair of wirings 81. However, the ends of the pair of wirings 81 on the side opposite to the detection unit 80 side are exposed from the protection part 52. The protection part 52 has, for example, a function of insulating the detection unit 80 and the wiring 81 and a function of protecting the detection unit 80 and the wiring 81 from external forces, corrosive gases, and the like. The material and formation method of the protection part 52 can be the same as those of the protection part 51 described above, for example.

[0031] Here, for example, when the heater 1 is in use or during manufacturing (for example, during firing of the protection parts 51, 52, etc.), thermal stress is generated due to the difference in the coefficient of thermal expansion of the materials. Therefore, there is a possibility that the heater 1 may warp due to the thermal stress. If the heater 1 warps, the distance between the heater 1 and the object to be heated may vary, and there is a possibility that heating unevenness may occur in the object to be heated.

[0032] In this case, on the side of the surface 10a of the substrate 10, the thermal stress generated by the substrate 10, the insulating portion 21, and the protective portion 51 can be offset by the thermal stress generated by the substrate 10, the insulating portion 22, and the protective portion 52 on the side of the surface 10b of the substrate 10. If the thermal stresses are offset, warping of the heater 1 can be suppressed. In this case, if the total thickness of the insulating portion 22 and the protective portion 52 is made approximately the same as the total thickness of the insulating portion 21 and the protective portion 51, the value of the thermal stress generated on the side of the surface 10b of the substrate 10 can be made close to the value of the thermal stress generated on the side of the surface 10a of the substrate 10. Therefore, warping of the heater 1 can be more effectively suppressed.

[0033] Here, in the case of a general heater used in an image forming apparatus or the like, the heating element and the portion for making an electrical connection to the outside are provided on the same side of the substrate. However, depending on, for example, the configuration of the fixing portion to which the heater is attached, there may be cases where it is preferable that the portion for making an electrical connection to the outside is provided on the side of the substrate opposite to the side where the heating element is provided. For example, in FIG. 7 described later, it may be preferable to provide the portion for making an electrical connection to the outside on the side of the heater 1 facing the paper 510 (the sliding surface side), and provide the heating element 30 on the side of the heater 1 opposite to the side of the paper 510 (the non-sliding surface side).

[0034] Also, when the portion for making an electrical connection to the outside is provided on the side of the substrate opposite to the side where the heating element is provided, it is preferable to provide the detection unit 80 and the pair of wirings 81 on the side of the substrate opposite to the side where the heating element is provided. By doing so, on the same side of the substrate, the portion for making an electrical connection to the outside and the pair of wirings 81 can be electrically connected to a harness or the like. Therefore, space saving, resource saving, and cost reduction of the harness can be achieved.

[0035] In this case, the heating element 30 and the portion for making an electrical connection with the outside can be electrically connected via a conductive member that penetrates the thickness direction of the substrate. However, if this is done, since it is necessary to provide holes in the substrate, the strength of the substrate will be reduced. If the strength of the substrate is reduced, there is a risk that the substrate may be deformed or damaged due to thermal stress generated during the use of the heater. Also, if holes are provided in the substrate, the dimension in the short side direction (width dimension) of the substrate will increase, making it difficult to miniaturize the heater.

[0036] Therefore, the heater 1 according to the present embodiment is provided with terminals 60 and a joint portion 70. As shown in FIGS. 1, 2, and 4, in the X direction, the terminals 60 and the joint portion 70 are provided at both end portions on both sides of the substrate 10. The terminal 60 has a plate shape and is formed of a material having heat resistance and conductivity. The terminal 60 can be formed of, for example, metal. The metal can be, for example, stainless steel, an aluminum alloy, or the like. The planar shape of the terminal 60 can be, for example, a quadrangle. The material, thickness, and width dimension (dimension in the Y direction) of the terminal 60 can be the same as or different from the material, thickness, and width dimension of the substrate 10. Also, the terminal 60 provided at one end portion of the substrate 10 and the terminal 60 provided at the other end portion of the substrate 10 may have the same material, planar shape, thickness, width dimension, and length (dimension in the X direction), or at least any one of these may be different.

[0037] The joint portion 70 is provided between the end of the substrate 10 and the end of the terminal 60. The joint portion 70 insulates between the substrate 10 and the terminal 60 and joins the substrate 10 and the terminal 60. The joint portion 70 is formed of a material having, for example, heat resistance and insulation properties. The joint portion 70 can be formed of an inorganic material such as a glass material. In this case, a glass material added with the above-described filler can also be used. The joint portion 70 can be formed, for example, by filling a paste-like material between the end of the substrate 10 and the end of the terminal 60 and curing it using a firing method or the like. In this way, a joint portion 70 can be formed between the end of the substrate 10 and the end of the terminal 60 that insulates between the substrate 10 and the terminal 60 and joins the substrate 10 and the terminal 60.

[0038] As shown in FIGS. 1, 2, and 3, the end of the insulating portion 21 can be provided on the terminal 60. In this case, the vicinity of the end of the terminal 60 on the side opposite to the substrate 10 side is exposed from the insulating portion 21. A wiring 40 is electrically connected to the portion of the terminal 60 that is exposed from the insulating portion 21.

[0039] On the other hand, the end of the insulating portion 22 is not provided on the terminal 60. Therefore, the surface 60a of the terminal 60 on the side opposite to the side where the heating element 30 is provided is exposed from the insulating portion 22. For example, a connector of a harness or the like can be electrically connected to a partial region 60a1 of the surface 60a. Note that if a part of the surface 60a is exposed from the insulating portion 22, the insulating portion 22 may be provided on the surface 60a of the terminal 60. For example, a hole or notch may be provided in the insulating portion 22, or a space may be provided between the end of the insulating portion 22 and the end of the terminal 60 to expose a part of the surface 60a from the insulating portion 22.

[0040] As described above, the heating element 30 is electrically connected to the terminal 60 via the wiring 40. Further, the terminal 60 has conductivity. Therefore, if a harness or the like is electrically connected to the surface 60a (region 60a1) of the terminal 60, the heating element 30 can be electrically connected to a power source, a control circuit, or the like.

[0041] Further, since the detection unit 80 and the pair of wirings 81 are provided on the same side of the substrate 10 as the surface 60a of the terminal 60, on the same side of the substrate 10, the surface 60a of the terminal 60 and the pair of wirings 81 can be electrically connected to a harness or the like. Therefore, it is possible to achieve space saving, resource saving, and cost reduction of the harness.

[0042] That is, in the case of the heater 1 according to the present embodiment, with a simple configuration, a portion for making an electrical connection to the outside (for example, the surface 60a (region 60a1) of the terminal 60) and the detection unit 80 can be provided on the side of the substrate 10 opposite to the side where the heating element 30 is provided. Further, since it is not necessary to provide a hole penetrating in the thickness direction of the substrate 10, it is possible to suppress deformation or breakage of the substrate 10 due to thermal stress. In addition, since the dimension (width dimension) in the short side direction of the substrate 10 can be reduced, miniaturization of the heater 1 becomes easy.

[0043] (Image forming apparatus) Next, the image forming apparatus 100 according to the present embodiment will be exemplified. In the following, as an example, the case where the image forming apparatus 100 is a copying machine will be described. However, the image forming apparatus 100 is not limited to a copying machine, and any apparatus provided with a heater for fixing toner may be used. For example, the image forming apparatus 100 may be a printer or the like. It may also be a rewritable card reader / writer or the like.

[0044] FIG. 6 is a schematic diagram for exemplifying the image forming apparatus 100 according to the present embodiment. FIG. 7 is a schematic diagram for exemplifying the fixing unit 200. As shown in FIG. 6, 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 discharging unit 151, a developing unit 160, a cleaner 170, a storage unit 180, a conveying unit 190, a fixing unit 200, and a controller 210.

[0045] Frame 110 is box-shaped and houses inside it an illumination unit 120, an imaging element 130, a photosensitive drum 140, a charging unit 150, a developing unit 160, a cleaner 170, a part of a storage unit 180, a conveyance unit 190, a fixing unit 200, and a controller 210. On the upper surface of frame 110, a window 111 made of a light-transmitting material such as glass can be provided. On window 111, an original document 500 to be copied is placed. Also, a moving unit for moving the position of original document 500 can be provided.

[0046] The illumination unit 120 is provided near window 111. The illumination unit 120 has, for example, a light source 121 such as a lamp and a reflecting mirror 122. The imaging element 130 is provided near window 111. The photosensitive drum 140 is provided below the illumination unit 120 and the imaging element 130. The photosensitive drum 140 is provided rotatably. On the surface of the photosensitive drum 140, for example, a zinc oxide photosensitive layer or an organic semiconductor photosensitive layer is provided. The charging unit 150, the discharging unit 151, the developing unit 160, and the cleaner 170 are provided around the photosensitive drum 140.

[0047] The storage unit 180 has, for example, a cassette 181 and a tray 182. The cassette 181 is detachably attached to one side portion of the frame 110. The tray 182 is provided on the side portion of the frame 110 opposite to the side where the cassette 181 is attached. In the cassette 181, paper 510 (for example, blank paper) before copying is stored. In the tray 182, paper 511 on which a copied image 511a is fixed is stored.

[0048] The conveyance unit 190 is provided below the photosensitive drum 140. The conveyance unit 190 conveys the paper 510 between the cassette 181 and the tray 182. The conveyance unit 190 has, for example, a guide 191 for supporting the conveyed paper 510 and conveyance rollers 192 - 194 for conveying the paper 510. Also, a motor for rotating the conveyance rollers 192 - 194 can be provided in the conveyance unit 190.

[0049] The fixing unit 200 is provided on the downstream side (the side of the tray 182) of the photosensitive drum 140. As shown in FIG. 7, the fixing unit 200 has, for example, a heater 1, a stay 201, a film belt 202, and a pressure roller 203. The heater 1 is attached to the stay 201 on the conveyance line side of the paper 510. The heater 1 can be embedded in the stay 201. For example, the side of the heater 1 where the protection part 51 is provided can be exposed from the stay 201.

[0050] The film belt 202 covers the stay 201 provided with the heater 1. The film belt 202 can be formed of a resin having heat resistance such as polyimide, for example.

[0051] The pressure roller 203 is provided so as to face the stay 201. The pressure roller 203 has, 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 of an elastic material having heat resistance. The elastic part 203c can be formed of, for example, a silicone resin or the like.

[0052] The controller 210 is provided inside the frame 110. The controller 210 has, for example, an arithmetic unit such as a CPU (Central Processing Unit), and a storage unit in which a control program is stored. The arithmetic unit controls the operations of the respective elements provided in the image forming apparatus 100 based on the control program stored in the storage unit. Further, the controller 210 can also include an operation unit for the user to input copy conditions and the like, a display unit for displaying the operation state and abnormality display, and the like. Note that since known techniques can be applied to the control of the respective elements provided in the image forming apparatus 100, detailed description thereof is omitted.

[0053] As described above, several embodiments of the present invention have been illustrated. However, these embodiments are presented as examples and are not intended to limit the scope of the invention. These novel embodiments can be implemented in various other forms, and various omissions, replacements, changes, etc. can be made without departing from the gist of the invention. These embodiments and their modifications are included in the scope and gist of the invention, and are also included in the invention described in the claims and the equivalent scope thereof. In addition, the above-described embodiments can be implemented in combination with each other.

Explanation of Reference Numerals

[0054] 1 Heater, 10 Substrate, 10a Surface, 10b Surface, 21 Insulating Portion, 22 Insulating Portion, 30 Heating Element, 40 Wiring, 51 Protection Portion, 52 Protection Portion, 60 Terminal, 60a Surface, 60a1 Region, 70 Joint Portion, 80 Detection Portion, 81 Wiring, 100 Image Forming Apparatus, 200 Fixing Portion

Claims

1. a substrate that contains metal, has a plate shape, and extends in one direction; a first insulating portion provided on the first surface of the substrate and having insulating properties; a heating element provided on the first insulating portion and extending in the longitudinal direction of the substrate; terminals provided at both ends of the substrate in the longitudinal direction of the substrate, having conductivity, and having a plate shape; a first wiring provided on the first insulating portion and electrically connected to the heating element and the terminal having conductivity; a joint portion provided between the end of the substrate and the terminal and having insulating properties; a second insulating portion provided on the second surface of the substrate facing the first surface and having insulating properties; at least one detection portion provided on the second insulating portion for detecting temperature; comprising a heater in which the surface of the terminal on the side opposite to the side where the heating element is provided is exposed from the second insulating portion.

2. a first protection portion provided on the first insulating portion, the heating element, and the first wiring and extending in the longitudinal direction of the substrate; a second wiring provided on the second insulating portion, extending in the longitudinal direction of the substrate, and having one end electrically connected to the detection portion; a second protection portion provided on the second insulating portion, the detection portion, and the second wiring and extending in the longitudinal direction of the substrate; comprising the heater according to claim 1, wherein the other end of the second wiring is exposed from the second protection portion.

3. the heater according to claim 1 or 2, wherein the detection portion is a thermistor and a plurality of them are provided.

4. an image forming apparatus comprising the heater according to any one of claims 1 to 3.

Images