Heater, and image forming apparatus

Abstract

To provide a heater that can prevent generation of steps on a surface of a protection part on a side opposite to a substrate side, and an image forming apparatus.SOLUTION: A heater according to an embodiment is provided with: a substrate extending in a first direction; protrusions provided on one face of the substrate; heating elements provided on one face side of the substrate and extending in the first direction; and a protection part provided on one face side of the substrate and covering the heating elements. When seen from a direction perpendicular to one face of the substrate, the protrusions are provided separate from the heating elements in a second direction orthogonal to the first direction.SELECTED DRAWING: Figure 3

Description

[Technical field]

[0001] An embodiment of the present invention relates to a heater and an image forming apparatus. [Background technology]

[0002] For example, an image forming apparatus such as a copier or a printer is provided with a heater for fixing toner. For example, such a heater includes 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 part provided on the other surface of the substrate to cover the heating element. The protective part is made of a material that has heat resistance and insulating properties, high thermal conductivity, and high chemical stability. For example, the protective part is made of glass.

[0003] Here, when forming the heater, a heating element is formed on one side of the substrate, a paste-like material is applied to one side of the substrate to cover the heating element, and the applied material is fired to form a protective portion that covers the heating element.

[0004] However, when the protective part is formed in this manner, in the region of the substrate surface where the heating element is provided, the protective part is formed on the heating element, whereas in the region of the substrate surface where the heating element is not provided, the protective part is formed on the substrate surface, and therefore, a step due to the thickness of the heating element may occur on the surface of the protective part opposite to the substrate side.

[0005] When the heater is in use, the surface of the protective part opposite the substrate is directed toward the object to be heated (such as paper with toner attached). Therefore, if there is a step on this surface, the distance between the object to be heated and the protective part will vary, which may result in uneven heating of the object to be heated. Therefore, there has been a need to develop a technique that can prevent the occurrence of steps on the surface of the protective portion opposite the substrate. [Prior art documents] [Patent documents]

[0006] [Patent Document 1] JP 2000-173752 A Summary of the Invention [Problem to be solved by the invention]

[0007] An object of the present invention is to provide a heater and an image forming apparatus that can prevent a step from occurring on the surface of the protection part opposite to the substrate side. [Means for solving the problem]

[0008] The heater according to the embodiment includes a substrate extending in a first direction, a protrusion provided on one surface of the substrate, a heating element provided on the one surface of the substrate and extending in the first direction, and a protective portion provided on the one surface of the substrate and covering the heating element. When viewed from a direction perpendicular to the one surface of the substrate, the protrusion is spaced apart from the heating element in a second direction perpendicular to the first direction. Effect of the Invention

[0009] According to the embodiment of the present invention, it is possible to provide a heater and an image forming apparatus capable of suppressing the occurrence of a step on the surface of the protection part opposite to the substrate side. [Brief description of the drawings]

[0010] [Figure 1] FIG. 2 is a schematic front view illustrating the heater according to the present embodiment. [Diagram 2] FIG. 4 is a schematic rear view illustrating the heater. [Diagram 3] 2 is a schematic cross-sectional view of the heater in the direction of line AA in FIG. 1. [Figure 4] FIG. 4 is a schematic cross-sectional view of a heater according to a comparative example. [Diagram 5] 4(a) to 4(f) are schematic cross-sectional views illustrating the cross-sectional shapes of the protrusions. [Figure 6]1 is a schematic diagram illustrating an image forming apparatus according to an embodiment of the present invention; [Figure 7] 3A and 3B are schematic diagrams for illustrating a fixing unit. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0011] Hereinafter, an embodiment will be illustrated with reference to the drawings. In each drawing, the same components are given the same reference numerals, and detailed description will be omitted as appropriate. In each drawing, arrows X, Y, and Z represent three mutually orthogonal directions. For example, the longitudinal direction (length direction) of the substrate is the X direction (corresponding to an example of a first direction), the lateral direction (width direction) of the substrate is the Y direction (corresponding to an example of a second direction), and the direction perpendicular to the surface of the substrate (thickness direction) is the Z direction.

[0012] (heater) FIG. 1 is a schematic front view illustrating a heater 1 according to the present embodiment. FIG. 1 is a view of the heater 1 as seen from the side where the heat generating portion 20 is provided. FIG. 2 is a schematic rear view illustrating the heater 1. As shown in FIG. FIG. 2 is a view of the heater 1 as viewed from the side where the warp mitigating portion 50 is provided (the side opposite to the side where the heat generating portion 20 is provided). FIG. 3 is a schematic cross-sectional view of the heater 1 in FIG. 1 taken along the line AA. As shown in FIGS. 1 to 3, the heater 1 has a substrate 10, an insulating layer 11, a heat generating portion 20, a wiring portion 30, a protective portion 40, a warpage mitigating portion 50, and a protruding portion 60, for example.

[0013] The substrate 10 is plate-like and has a surface 10a and a surface 10b opposite to the surface 10a. The substrate 10 has a shape extending in the X direction. The shape of the substrate 10 as 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 depending on the size of the object to be heated (for example, paper with toner attached thereto) and the number and arrangement of heating elements described below.

[0014] The substrate 10 is made of a material having heat resistance and high thermal conductivity, and can be made of, for example, a metal such as stainless steel or an aluminum alloy, or an inorganic material such as ceramics.

[0015] The thermal conductivity of metals is higher than that of inorganic materials such as ceramics. Therefore, if the substrate 10 is made of a metal, it is possible to suppress the occurrence of in-plane distribution of the temperature of the heater 1. In addition, it is possible to improve the rigidity of the substrate 10 and reduce the manufacturing cost. Generally, inorganic materials such as ceramics have insulating properties, so if the substrate 10 is made of an inorganic material, the insulating layer 11, which will be described later, can be omitted. The heater 1 illustrated in FIGS. 1 to 3 includes a substrate 10 containing a metal and an insulating layer 11. As shown in FIG.

[0016] The insulating layer 11 is provided on the surface 10a of the substrate 10 on which the heat generating portion 20 is provided. The insulating layer 11 is provided between the surface 10a of the substrate 10 and the heat generating portion 20. The insulating layer 11 covers the area of ​​the surface 10a of the substrate 10 on which the heat generating portion 20 is provided. The insulating layer 11 is formed from a material having heat resistance and insulating properties. There is no particular limitation on the material of the insulating layer 11 as long as it has heat resistance and insulating properties. The material of the insulating layer 11 can be, for example, glass or ceramics. There is no particular limitation on the thickness of the insulating layer 11 as long as insulation can be ensured.

[0017] The heat generating portion 20 converts the applied power into heat (Joule heat). The heat generating portion 20 is provided on the surface 10a side of the substrate 10. The heat generating portion 20 and the substrate 10 are insulated from each other by an insulating layer 11. The heat generating section 20 has, for example, a heat generating element 21 and a heat generating element 22. Although the case where the heat generating element 21 and the heat generating element 22 are provided has been illustrated as an example, the number and size of the heat generating elements can be appropriately changed depending on the size of the substrate 10 and the size of the object to be heated. Also, multiple types of heat generating elements with different lengths, widths, shapes, etc. can be provided. That is, it is sufficient that at least one heat generating element is provided.

[0018] Heating element 21 and heating element 22 can be arranged, for example, at a predetermined interval in the Y direction (short side direction of substrate 10). Heating element 21 and heating element 22 extend, for example, in the X direction (longitudinal direction of substrate 10).

[0019] The dimensions (length dimensions) of the 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 the heating elements 21 and 22 are located on the straight line 1a. In other words, it is preferable that the heating elements 21 and 22 each have a shape that is line-symmetrical with respect to the straight line 1a.

[0020] When the heater 1 is attached 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 size of the object to be heated in the direction perpendicular to the transport direction changes, the object to be heated can be heated approximately uniformly.

[0021] The electric resistance values ​​of the heating element 21 and the heating element 22 can be approximately the same or different. For example, the electric resistance values ​​of the heating element 21 and the heating element 22 can be approximately the same by making the dimensions in the X direction (length dimension), the Y direction (width dimension), and the Z direction (thickness dimension) of the heating element 21 and the heating element 22 approximately the same. Furthermore, by changing at least one of these dimensions, the electric resistance values ​​of the heating element 21 and the heating element 22 can be made different. Furthermore, by changing the material, the electric resistance values ​​of the heating element 21 and the heating element 22 can be made different.

[0022] Furthermore, the electrical resistance value per unit length of the heating element 21 can be approximately uniform in the X direction. For example, the dimension (width dimension) in the Y direction and the dimension (thickness dimension) in the Z direction of the heating element 21 can be approximately constant. In this case, the shape of the heating element 21 as viewed from the Z direction can be, for example, approximately rectangular extending in the X direction.

[0023] Furthermore, the electrical resistance value per unit length of the heating element 22 can be approximately uniform in the X direction. For example, the dimension (width dimension) in the Y direction and the dimension (thickness dimension) in the Z direction of the heating element 22 can be approximately constant. In this case, the shape of the heating element 22 as viewed from the Z direction can be, for example, approximately rectangular extending in the X direction.

[0024] Heating element 21 and heating element 22 can be formed using, for example, ruthenium oxide (RuO2), a silver-palladium (Ag-Pd) alloy, etc. Heating element 21 and heating element 22 can be formed, for example, by applying a paste-like material onto insulating layer 11 using a screen printing method or the like, and curing it using a baking method or the like. When the substrate 10 is made of an insulating material, the heating elements 21 and 22 can be formed, for example, by applying a paste-like material onto the surface 10a of the substrate 10 using a screen printing method or the like, and then hardening it using a firing method or the like.

[0025] The wiring portion 30 is provided on the surface 10a side of the substrate 10. The wiring portion 30 and the substrate 10 are insulated from each other by an insulating layer 11. The wiring section 30 includes, for example, a terminal 31, a terminal 32, a wire 33, a wire 34, and a wire 35.

[0026] The terminals 31 and 32 are provided, for example, near one end of the substrate 10 in the X direction. The terminals 31 and 32 are provided, for example, side by side in the X direction. The terminals 31 and 32 are electrically connected, for example, to a controller 210 of the image forming apparatus 100 (described later) via a connector, wiring, or the like.

[0027] The wiring 33 is provided, for example, in the X direction, on the side of the substrate 10 where the terminal 31 is provided. The wiring 33 extends in the X direction. The wiring 33 is electrically connected to the terminal 31 and an end of the heating element 21 on the terminal 31 side.

[0028] The wiring 34 is provided, for example, in the X direction, near the end of the substrate 10 opposite to the side on which the terminals 31 and 32 are provided. The end of the heating element 21 opposite to the wiring 33 side and the end of the heating element 22 opposite to the wiring 35 side are electrically connected to the wiring 34.

[0029] The wiring 35 is provided, for example, in the X direction, on the side of the substrate 10 where the terminal 32 is provided. The wiring 35 extends in the X direction. The wiring 35 is electrically connected to the terminal 32 and the end of the heating element 22 on the terminal 32 side.

[0030] The wiring portion 30 (terminals 31, 32, and wires 33 to 35) are formed using a material containing, for example, silver, copper, etc. For example, the terminals 31, 32, and wires 33 to 35 can be formed by applying a paste-like material onto the insulating layer 11 using a screen printing method or the like, and curing it using a baking method or the like. In addition, when the substrate 10 is made of an insulating material, the terminals 31, 32, and the wirings 33 to 35 can be formed, for example, by applying a paste-like material onto the surface 10a of the substrate 10 using a screen printing method or the like, and then hardening it using a firing method or the like.

[0031] The protective portion 40 is provided on the surface 10a side of the substrate 10. For example, the protective portion 40 is provided on the insulating layer 11. When the substrate 10 is made of an insulating material, the protective portion 40 is provided on the surface 10a of the substrate 10. The protective portion 40 covers the heat generating portion 20 (heat generating element 21 and heat generating element 22) and a part of the wiring portion 30 (wires 33, 34, and 35). In this case, the terminals 31 and 32 of the wiring portion 30 are exposed from the protective portion 40.

[0032] The protective section 40 extends in the X direction. The protective section 40 has, for example, a function of insulating the heat generating section 20 and a part of the wiring section 30, a function of transmitting heat generated in the heat generating section 20 to a heated object, and a function of protecting the heat generating section 20 and a part of the wiring section 30 from external forces, corrosive gases, and the like. The protective section 40 is formed from a material that has heat resistance and insulating properties, and has chemical stability and high thermal conductivity. The protective section 40 is formed from, for example, glass. In this case, the protective section 40 can also be formed using glass to which a filler containing a material with high thermal conductivity, such as aluminum oxide, has been added.

[0033] The heater 1 may further include a detection unit for detecting the temperature of the heat generating unit 20 and the temperature of the substrate 10. The detection unit may be, for example, a thermistor. The detection unit may be provided on at least one of the side of the substrate 10 on which the heat generating unit 20 is provided and the side of the substrate 10 opposite to the side on which the heat generating unit 20 is provided. For example, the detection unit and the wiring and terminals electrically connected to the detection unit may be provided on the insulating layer 11. In addition, when the substrate 10 is made of an insulating material, the detection unit and the wiring and terminals electrically connected to the detection unit may be provided on the substrate 10. In addition, the detection unit and the wiring may be covered by the protective unit 40. The terminals electrically connected to the detection unit may be exposed from the protective unit 40.

[0034] As described above, the material of the substrate 10 may be different from the material of the insulating layer 11 and the material of the protective portion 40. Different materials have different linear expansion coefficients. In addition, when the heater 1 is used, the substrate 10, the insulating layer 11, and the protective portion 40 are heated when the heating portion 20 is heated. When the heater 1 is manufactured, the substrate 10, the insulating layer 11, and the protective portion 40 are heated when the heating portion 20, the wiring portion 30, the insulating layer 11, and the protective portion 40 are baked. Therefore, when the heater 1 is used or manufactured, thermal stress occurs due to the difference in the linear expansion coefficients of the materials. When thermal stress occurs on one side of the substrate 10, the heater 1 may warp. When the heater 1 warps more, the distance between the heater 1 and the object to be heated varies, and there is a risk of uneven heating of the object to be heated.

[0035] 2 and 3, the heater 1 is provided with a warpage mitigating portion 50. The warpage mitigating portion 50 is provided on the surface 10b of the substrate 10, which faces the surface 10a. If the warpage mitigating portion 50 is provided on the surface 10b of the substrate 10, the thermal stress generated on the surface 10a side of the substrate 10 can be offset by the thermal stress generated on the surface 10b side of the substrate 10. Therefore, it is possible to suppress the occurrence of warpage in the heater 1 when the heater 1 is used or when the heater 1 is manufactured.

[0036] The material of the warp mitigation parts 50 can be, for example, the same as the material of the protective part 40. The dimensions, arrangement, and number of the warp mitigation parts 50 can be appropriately determined depending on the warp that occurs. The material, dimensions, arrangement, and number of the warp mitigation parts 50 can be appropriately determined, for example, by conducting experiments or simulations. If the amount of warping that occurs is small, the warping mitigating portion 50 may be omitted.

[0037] Next, the protrusion 60 will be described. FIG. 4 is a schematic cross-sectional view of a heater 70 according to a comparative example. FIG. 4 corresponds to FIG.

[0038] As described above, the protective part 40 is provided so as to cover the heat generating part 20 (heat generating element 21 and heat generating element 22) by using a screen printing method, a baking method, or the like. Therefore, in the region where the heat generating element 21 and the heat generating element 22 are provided, the protective part 40 is formed on them. In the region where the heat generating element 21 and the heat generating element 22 are not provided, the protective part 40 is formed on the insulating layer 11 (on the surface 10a of the substrate 10 when the insulating layer 11 is not provided). Therefore, as shown in FIG. 4, a step 40a1 due to the thickness of the heat generating element and wiring may be generated on the surface of the protective part 40 opposite to the substrate 10 side.

[0039] When the heater 1 is used, the surface of the protective part 40 opposite to the substrate 10 is directed toward the object to be heated. Therefore, if the step 40a becomes large, the variation in the distance between the object to be heated and the protective part 40 increases, which may cause uneven heating of the object to be heated.

[0040] 1 and 3, the heater 1 is provided with a protrusion 60. For example, the protrusion 60 can be provided on the surface 10a of the substrate 10. The protrusion 60 extends in the direction in which the heating element extends (X direction).

[0041] When viewed from a direction (Z direction) perpendicular to the surface 10a of the substrate 10, the protrusion 60 is provided at a distance from the heating element in a direction (Y direction) perpendicular to the direction (X direction) in which the heating element extends. When a plurality of heating elements are provided side by side, the protrusion 60 can be provided between the heating elements. Since the heater 1 illustrated in FIG. 1 and FIG. 3 includes the heating element 21 and the heating element 22, the protrusion 60 can be provided between the heating element 21 and the heating element 22. For example, as shown in FIG. 3, in the Y direction, the distance L1 (mm) between the protrusion 60 and the heating element 21 can be the same as the distance L2 (mm) between the protrusion 60 and the heating element 22.

[0042] Moreover, the wiring 33, wiring 34, and wiring 35 are generally provided outside the region where the heating object is heated. Therefore, even if a step is formed above the wiring 33, wiring 34, and wiring 35, it has almost no effect on uneven heating of the heating object. For example, when viewed from the Z direction, the protrusion 60 may overlap at least one of the wiring 33, wiring 34, and wiring 35. In this way, the degree of freedom in designing the arrangement of the protrusion 60, wiring 33, wiring 34, and wiring 35 can be increased.

[0043] However, the terminals 31 and 32 are electrically connected to, for example, a controller 210 of the image forming apparatus 100 described later via a connector, wiring, etc. Therefore, if the protruding portion 60 overlaps with the terminals 31 and 32 when viewed from the Z direction, the terminals 31 and 32 may be deformed, making it difficult to connect them to the connector. Therefore, it is preferable that the protruding portion 60 does not overlap with the terminals 31 and 32 when viewed from the Z direction.

[0044] As shown in FIG. 3, when the insulating layer 11 is provided, the insulating layer 11 is formed on the convex portion 60. Therefore, the insulating layer 11 in the region where the convex portion 60 is provided protrudes upward. Since the protective portion 40 is formed on the insulating layer 11, the protective portion 40 protrudes upward in the region where the insulating layer 11 protrudes upward. That is, in the region where the heating element is not provided, the surface of the protective portion 40 opposite the substrate 10 side can be made to protrude upward. Therefore, it is possible to suppress the occurrence of a step 40a on the surface of the protective portion 40 opposite the substrate 10 side.

[0045] When the insulating layer 11 is not provided, the protective portion 40 is formed on the convex portion 60, so that the protective portion 40 protrudes upward in the region where the convex portion 60 is provided. That is, in the region where the heating element is not provided, the surface of the protective portion 40 opposite the substrate 10 side can be made to protrude upward. Therefore, it is possible to prevent a step 40a from being generated on the surface of the protective portion 40 opposite the substrate 10 side.

[0046] In this case, the thickness of the protrusion 60 can control the amount of protrusion of the surface of the protective part 40 opposite to the substrate 10, and thus the dimension of the step 40a in the Z direction. In this case, if the thickness of the protrusion 60 is made too thin or too thick relative to the thickness of the heating element, the dimension of the step 40a in the Z direction becomes large. Therefore, for example, when the thickness of the heating element is Tr (mm) and the thickness of the protrusion 60 is Tm (mm), it is preferable to satisfy "0.5 x Tr (mm) ≦ Tm (mm) ≦ 1.5 x Tr (mm)". In this way, the dimension of the step 40a in the Z direction can be reduced.

[0047] Furthermore, if the distance L1 (mm) between the protrusion 60 and the heating element 21 in the Y direction is made too large, the dimension of the step 40a in the Z direction will become large. Furthermore, if the distance L2 (mm) between the protrusion 60 and the heating element 22 in the Y direction is made too large, the dimension of the step 40a in the Z direction will become large. Therefore, it is preferable to satisfy "0 mm ≦ L1 (mm) ≦ 1.0 mm" and "0 mm ≦ L2 (mm) ≦ 1.0 mm." In this way, the dimension of the step 40a in the Z direction can be reduced.

[0048] Furthermore, if the distance L1 (mm) between the protrusion 60 and the heating element 21 in the Y direction is made too small, the dielectric strength between the protrusion 60 and the heating element 21 may become too small. Furthermore, if the distance L2 (mm) between the protrusion 60 and the heating element 22 in the Y direction is made too small, the dielectric strength between the protrusion 60 and the heating element 22 may become too small. Therefore, it is preferable to satisfy "0.3 mm ≦ L1 (mm) ≦ 1.0 mm" and "0.3 mm ≦ L2 (mm) ≦ 1.0 mm." In this way, the dimension of the step 40a in the Z direction can be reduced, and further, it becomes easier to ensure the dielectric strength voltage between the protrusion 60 and the heating element 21 (heating element 22).

[0049] The dimension (width dimension) of the protrusion 60 in the Y direction can be changed appropriately depending on the distance between the heat generating element 21 and the heat generating element 22, etc.

[0050] The protrusions 60 can be formed, for example, by applying a paste-like material to the surface 10a of the substrate 10 using a screen printing method or the like, and then curing the paste using a baking method or the like. In this case, the material of the protrusions 60 can be the same as any one of the material of the heat generating portion 20, the material of the wiring portion 30, the material of the insulating layer 11, and the material of the protective portion 40. In this way, the manufacturing cost can be reduced. The protrusion 60 can also be joined to the surface 10a of the substrate 10 by welding or using a heat-resistant joining material.

[0051] The protrusions 60 can also be formed integrally with the substrate 10. For example, when the substrate 10 is made of metal, the protrusions 60 can be formed on the surface 10a of the substrate 10 by cutting, pressing, or the like. For example, when the substrate 10 is made of ceramics, the protrusions 60 can be formed on the surface 10a of the substrate 10 by cutting, or the protrusions 60 can be formed on the surface 10a of the substrate 10 when forming a blank.

[0052] In addition, in FIG. 3, the cross-sectional shape of the protrusion 60 when viewed from the extending direction (X direction) is rectangular, but this is not limiting. 5(a) to (f) are schematic cross-sectional views illustrating the cross-sectional shapes of the convex portions. 5(a) to 5(c) show a case where the protrusions 60a, 60b, and 60c are formed by, for example, pressing a metal plate. 5(d) to (f) show the case where protrusions 60a1, 60b1, and 60c1 are formed by molding a ceramic green sheet or the like. In this way, the cross-sectional shape of the protrusions can be changed as appropriate. In this case, it is preferable that the top surfaces of the protrusions are flat. If the top surfaces of the protrusions are flat, the formation of the steps 40a can be suppressed in a wider area.

[0053] In the above, the protrusion 60 extending in the direction in which the heating element extends has been exemplified, but multiple protrusions aligned in the direction in which the heating element extends may be provided. Also, multiple protrusions aligned in a direction perpendicular to the direction in which the heating element extends may be provided. The dimensions, cross-sectional shape, number and arrangement of the protrusions can be appropriately determined, for example, by conducting experiments or simulations.

[0054] (Image forming device) In one embodiment of the present invention, it is possible to provide an image forming apparatus 100 equipped with a heater 1. The above description of the heater 1 and modified examples of the heater 1 (for example, the convex portions 60a, 60b, 60c, 60a1, 60b1, 60c1, and those in which a person skilled in the art appropriately adds, deletes, or modifies components and has the features of the present invention) can all be applied to the image forming apparatus 100.

[0055] In the following, a case will be described as an example in which the image forming apparatus 100 is a copier. However, the image forming apparatus 100 is not limited to a copier, and may be a printer, a rewritable card reader / writer, or the like.

[0056] FIG. 6 is a schematic diagram illustrating an image forming apparatus 100 according to the present embodiment. FIG. 7 is a schematic diagram illustrating the fixing unit 200. As shown in FIG. As shown in FIG. 6, the image forming apparatus 100 includes, for example, a frame 110, an illumination section 120, an imaging element 130, a photosensitive drum 140, a charging section 150, a discharging section 151, a developing section 160, a cleaner 170, a storage section 180, a conveying section 190, a fixing section 200, and a controller 210.

[0057] The frame 110 is box-shaped and houses therein an illumination section 120, an imaging element 130, a photosensitive drum 140, a charging section 150, a developing section 160, a cleaner 170, part of a storage section 180, a transport section 190, a fixing section 200, and a controller 210. A window 111 made of a light-transmitting material such as glass may be provided on the upper surface of the frame 110. An original 500 to be copied is placed on the window 111. Also, a moving unit for moving the position of the original 500 may be provided.

[0058] The illumination unit 120 is provided near the window 111. The illumination unit 120 has a light source 121, such as a lamp, and a reflecting mirror 122, for example. The imaging element 130 is provided near the 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 .

[0059] The storage section 180 has, 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 provided on the side of the frame 110 opposite to the side on which the cassette 181 is attached. The cassette 181 stores paper 510 (e.g., blank paper) before copying. The tray 182 stores paper 511 on which a copy image 511a is fixed.

[0060] The transport unit 190 is provided 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 has, for example, a guide 191 that supports the transported paper 510, and transport rollers 192-194 that transport the paper 510. The transport unit 190 can also be provided with a motor that rotates the transport rollers 192-194.

[0061] The fixing unit 200 is provided downstream of the photosensitive drum 140 (on the tray 182 side). As shown in FIG. 7, the fixing unit 200 includes, 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 side of the conveyance line for the paper 510. The heater 1 can be embedded in the stay 201. In this case, the side of the heater 1 on which the protective part 40 is provided 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 contain, for example, a heat-resistant resin such as polyimide.

[0063] The pressure roller 203 is disposed 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 portion 203c. The drive shaft 203b protrudes from an end of the core metal 203a and is connected to a drive device such as a motor. The elastic portion 203c is disposed on the outer surface of the core metal 203a. The elastic portion 203c is formed from a heat-resistant elastic material. The elastic portion 203c may contain, for example, a silicone resin.

[0064] Controller 210 is provided inside frame 110. Controller 210 has, for example, a calculation unit such as a CPU (Central Processing Unit) and a storage unit in which a control program is stored. The calculation unit controls the operation of each element provided in image forming apparatus 100 based on the control program stored in the storage unit. Controller 210 can also include an operation unit through which a user inputs copying conditions, a display unit that displays the operating state, an error display, and the like. In addition, since known techniques can be applied to the control of each element provided in the image forming apparatus 100, detailed description thereof will be omitted.

[0065] Although some embodiments of the present invention have been illustrated above, 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, substitutions, modifications, 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 included in the scope of the invention and its equivalents described in the claims. In addition, the above-mentioned embodiments can be implemented in combination with each other.

[0066] Below, additional notes regarding the above-described embodiment are given.

[0067] (Appendix 1) A substrate extending in a first direction; A convex portion provided on one surface of the substrate; a heating element provided on the one surface side of the substrate and extending in the first direction; a protective portion provided on the one surface side of the substrate and covering the heating element; Equipped with the heater, when viewed from a direction perpendicular to the one surface of the substrate, the protrusion is spaced apart from the heating element in a second direction perpendicular to the first direction.

[0068] (Appendix 2) 2. The heater according to claim 1, wherein the following formula is satisfied, where Tr (mm) is the thickness of the heating element and Tm (mm) is the thickness of the protrusion. 0.5×Tr(mm)≦Tm(mm)≦1.5×Tr(mm)

[0069] (Appendix 3) 3. The heater according to claim 1 or 2, wherein the following formula is satisfied when the distance between the protrusion and the heating element in the second direction is L (mm): 0mm≦L(mm)≦1.0mm

[0070] (Appendix 4) the substrate comprises a metal; Further comprising an insulating layer provided between the one surface of the substrate and the heating element, 4. The heater according to claim 1, wherein the insulating layer covers the protrusion.

[0071] (Appendix 5) An image forming apparatus comprising the heater according to any one of claims 1 to 4. [Explanation of symbols]

[0072] REFERENCE SIGNS LIST 1 heater, 10 substrate, 10a surface, 10b surface, 11 insulating layer, 20 heat generating portion, 21 heat generating element, 22 heat generating element, 30 wiring portion, 40 protective portion, 50 warp mitigation portion, 60 convex portion, 60a convex portion, 60b convex portion, 60c convex portion, 60a1 convex portion, 60b1 convex portion, 60c1 convex portion, 100 image forming apparatus, 200 fixing portion

Claims

1. A substrate extending in a first direction; A protrusion provided on one surface of the substrate; a heating element provided on the one surface side of the substrate and extending in the first direction; a protective portion provided on the one surface side of the substrate and covering the heating element; Equipped with The heater, when viewed from a direction perpendicular to the one surface of the substrate, the protrusion is spaced apart from the heating element in a second direction perpendicular to the first direction.

2. 2. The heater according to claim 1, wherein the following formula is satisfied, where Tr (mm) is the thickness of the heating element and Tm (mm) is the thickness of the protrusion. 0.5×Tr (mm)≦Tm (mm)≦1.5×Tr (mm)

3. 3. The heater according to claim 1, wherein the following formula is satisfied, where L (mm) is a distance between the protrusion and the heating element in the second direction: L=L / mm. 0mm≦L(mm)≦1.0mm

4. the substrate comprises a metal; Further comprising an insulating layer provided between the one surface of the substrate and the heating element, The heater according to claim 1 , wherein the insulating layer covers the protrusion.

5. 2. An image forming apparatus comprising the heater according to claim 1.

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