Heater and image forming apparatus

Abstract

The objective is to provide a heater and an image forming apparatus that can reduce manufacturing costs even when a protrusion is provided on the substrate. [Solution] The heater according to the embodiment comprises: a plate-shaped substrate containing metal, having a first surface and a second surface facing the first surface, 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; and a protective part covering the heating element. The substrate has a convex portion provided on the second surface and extending in the first direction; and a recess opening on the first surface and extending in the first direction. When viewed from a second direction intersecting the first surface, the recess overlaps with the convex portion.

Description

Technical Field

[0001] Embodiments of the present invention relate to a heater and an image forming apparatus.

Background Art

[0002] For example, image forming apparatuses such as copiers and printers are provided with a heater 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] Here, if the material of the substrate is metal, the rigidity of the substrate can be improved. However, since the protective portion is formed of an inorganic material such as ceramics or glass, the material of the substrate and the material of the protective portion are different. Therefore, the coefficient of thermal expansion of the material of the substrate and the coefficient of thermal expansion of the material of the protective portion are different, and thermal stress may occur due to the difference in the coefficient of thermal expansion. When thermal stress occurs, the heater is likely to warp. If the warp of the heater increases, the distance between the heater and the heating object varies, and there is a risk of uneven heating on the heating object. Therefore, a technique has been proposed in which convex ribs are provided on the substrate to increase the rigidity of the substrate.

[0004] However, when convex ribs are provided on the substrate using welding or bending, it is difficult to reduce the manufacturing cost. Therefore, there has been a demand for the development of a technique that can reduce the manufacturing cost even when convex portions are provided on the substrate.

Prior Art Documents

Patent Documents

[0005]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0006] The problem that this invention aims to solve is to provide a heater and an image forming apparatus that can reduce manufacturing costs even when a protrusion is provided on the substrate. [Means for solving the problem]

[0007] The heater according to the embodiment comprises: a plate-shaped substrate containing metal, having a first surface and a second surface facing the first surface, and 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; and a protective portion covering the heating element. The substrate has a convex portion provided on the second surface and extending in the first direction; and a recess opening on the first surface and extending in the first direction. When viewed from a second direction intersecting the first surface, the recess overlaps with the convex portion. [Effects of the Invention]

[0008] According to embodiments of the present invention, it is possible to provide a heater and an image forming apparatus that can reduce manufacturing costs even when a protrusion is provided on the substrate. [Brief explanation of the drawing]

[0009] [Figure 1] This is a schematic front view illustrating the heater according to this embodiment. [Figure 2] This is a schematic cross-sectional view of the heater in the direction of line AA in Figure 1. [Figure 3] (a) and (b) are schematic cross-sectional views illustrating the adjustment of the substrate shape. [Figure 4] This is a schematic front view illustrating a heater according to another embodiment. [Figure 5] Figure 4 is a schematic cross-sectional view of the heater in the direction of the BB line. [Figure 6] This is a schematic diagram illustrating an image forming apparatus according to this embodiment. [Figure 7]This is a schematic diagram illustrating the fixing section. [Modes for carrying out the invention]

[0010] The embodiments will be illustrated below with reference to the drawings. In each drawing, similar components are denoted by the same reference numerals, and detailed explanations 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 (corresponding to an example of the first direction), the short direction (width direction) of the substrate is the Y direction, and the direction perpendicular to the surface of the substrate is the Z direction (corresponding to an example of the second direction).

[0011] (heater)

[0012] Figure 1 is a schematic front view illustrating the heater 1 according to this embodiment. Figure 1 shows the heater 1 as viewed from the side where the heating element 30 is provided, in the Z direction. Figure 2 is a schematic cross-sectional view of heater 1 in the direction of line AA in Figure 1. As shown in Figures 1 and 2, the heater 1 includes, for example, a substrate 10, an insulating layer 20, a heating element 30, a wiring element 40, and a protective element 50.

[0013] The substrate 10 is plate-shaped and has a surface 10a (corresponding to an example of a first surface) and a surface 10b (corresponding to an example of a second surface) opposite to surface 10a. The substrate 10 has a shape that extends in the X direction. The shape of the substrate 10 as viewed from the Z direction is, for example, a long rectangle. 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 (for example, paper).

[0014] The substrate 10 is formed from a material that has heat resistance and high thermal conductivity. For example, the substrate 10 can be formed from a metal such as stainless steel or an aluminum alloy. The thermal conductivity of metal is higher than that of inorganic materials such as ceramics. Therefore, if the substrate 10 contains 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.

[0015] Also, as shown in FIG. 2, a convex portion 10c is provided at the central portion of the surface 10b of the substrate 10 in the Y direction. As shown in FIG. 1, the convex portion 10c extends in the X direction. In the heater 1 illustrated in FIG. 1, the convex portion 10c extends between one end and the other end of the substrate 10 in the X direction. As shown in FIG. 2, the convex portion 10c protrudes in the Z direction from the surface 10b of the substrate 10.

[0016] Also, as shown in FIG. 2, a concave portion 10d is open at the central portion of the surface 10a of the substrate 10 in the Y direction. As shown in FIG. 1, the concave portion 10d extends in the X direction. In the heater 1 illustrated in FIG. 1, the concave portion 10d extends between one end and the other end of the substrate 10 in the X direction. Further, the concave portion 10d is further open at one end and the other end of the substrate 10 in the X direction.

[0017] When viewed from the Z direction, the concave portion 10d is provided at a position overlapping the convex portion 10c. In this case, the center line of the concave portion 10d extending in the X direction can be made to overlap the center line of the convex portion 10c extending in the X direction.

[0018] The insulating layer 20 is provided on the surface 10a of the substrate 10. The insulating layer 20 has an insulating layer 21 and an insulating layer 22. The insulating layer 21 is provided on one side of the recess 10d on the surface 10a of the substrate 10. The insulating layer 22 is provided on the other side of the recess 10d on the surface 10a of the substrate 10. The insulating layer 20 is not provided in the recess 10d. That is, the insulating layer 20 covers the region on the surface 10a of the substrate 10 where the heat generating portion 30 is provided, and does not cover the region where the recess 10d on the surface 10a of the substrate 10 opens. The insulating layer 20 is formed of a material having heat resistance and insulation properties. The insulating layer 20 can be formed of an inorganic material such as ceramics, for example. The insulating layer 20 can be formed by, for example, thermal spraying or the like.

[0019] The heat generating portion 30 converts the applied electric power into heat (Joule heat). The heat generating portion 30 is provided on the insulating layer 20. The heat generating portion 30 and the substrate 10 are insulated by the insulating layer 20.

[0020] The heat generating portion 30 has, for example, a heating element 31 provided on the insulating layer 21 and a heating element 32 provided on the insulating layer 22. As an example, the case where one heating element 31 and one heating element 32 are provided respectively is illustrated, but the number and size of the heating elements can be appropriately changed according to the size of the substrate 10, the size of the object to be heated, and the like. For example, a plurality of heating elements 31 can be arranged side by side in the Y direction on the insulating layer 21, or a plurality of heating elements 32 can be arranged side by side in the Y direction on the insulating layer 22. Also, for example, heating elements having different lengths, widths, shapes, etc. can be provided.

[0021] The heating element 31 and the heating element 32 are arranged side by side in the Y direction, for example, with the recess 10d interposed therebetween. The heating element 31 and the heating element 32 extend in the X direction, for example. In this case, as shown in FIG. 1, the dimension of the heating element 32 in the X direction can be different from the dimension of the heating element 31 in the X direction. The dimension of the heating element 32 in the Y direction and the dimension in the Z direction may be the same as or different from the dimension of the heating element 31 in the Y direction and the dimension in the Z direction.

[0022] In the heater 1 illustrated in Figure 1, the dimensions of the heating element 32 in the X direction are shorter than the dimensions of the heating element 31 in the X direction. The dimensions of the heating element 32 in the Y direction and the Z direction are the same as the dimensions of the heating element 31 in the Y direction and the Z direction. For example, if the dimensions of the object to be heated in the X direction are small, power can be applied to the heating element 32, and if the dimensions of the object to be heated in the X direction are large, power can be applied to the heating element 31. In this way, wasted power can be suppressed, thereby saving energy and preventing the temperature of components provided around the heater 1 from becoming too high.

[0023] In this case, as shown in Figure 1, it is preferable that the centers of the heating elements 31 and 32 in the X direction lie on the straight line 1a. That is, it is preferable that the heating elements 31 and 32 each have a shape that is symmetrical with respect to the straight line 1a as the axis of symmetry.

[0024] 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 intersecting the transport direction, the object to be heated can be heated substantially uniformly.

[0025] The electrical resistance per unit length of heating elements 31 and 32 can be approximately constant or partially different. For example, by making the dimensions in the X direction (length), Y direction (width), and Z direction (thickness) of heating elements 31 and 32 approximately constant, the electrical resistance per unit length can be made approximately constant. In this case, the shapes of heating elements 31 and 32, as viewed from the Z direction, can be, for example, approximately rectangles extending in the X direction.

[0026] Furthermore, by changing at least one of the dimensions in the X direction (length), Y direction (width), and Z direction (thickness), the electrical resistance values ​​of the heating element 31 and the heating element 32 can be partially different.

[0027] If the electrical resistance values ​​per unit length of heating element 31 and heating element 32 are approximately constant, the amount of heat generated per unit length of heating element 31 and heating element 32 can be made approximately constant. If the electrical resistance values ​​of heating element 31 and heating element 32 are partially different, the temperature distribution on the object to be heated can be adjusted, or the object to be heated can be partially heated.

[0028] The heating elements 31 and 32 can be formed using, for example, ruthenium oxide (RuO2), silver-palladium (Ag-Pd) alloy, etc. The heating elements 31 and 32 can be formed by, for example, applying a paste-like material onto the insulating layer 21 and insulating layer 22 using a screen printing method, and then curing them using a firing method, etc.

[0029] The wiring section 40 is provided on top of the insulating layer 20. The wiring section 40 and the substrate 10 are insulated from each other by the insulating layer 20. The wiring section 40 includes, for example, a wiring section 41 provided on the insulating layer 21, and a wiring section 42 provided on the insulating layer 22.

[0030] The wiring section 41 has terminals 41a, wiring 41b, and wiring 41c. For example, a pair of terminals 41a can be provided. As shown in Figure 1, one terminal 41a can be provided near one end of the substrate 10 in the X direction. The other terminal 41a can be provided near the other end of the substrate 10 in the X direction. Wiring 41b extends in the X direction and is electrically connected to one terminal 41a and one end of the heating element 31. Wiring 41c extends in the X direction and is electrically connected to the other terminal 41a and the other end of the heating element 31.

[0031] The wiring section 42 has terminals 42a, wiring 42b, and wiring 42c. For example, a pair of terminals 42a can be provided. As shown in Figure 1, one terminal 42a can be provided near one end of the substrate 10 in the X direction. The other terminal 42a can be provided near the other end of the substrate 10 in the X direction. Wiring 42b extends in the X direction and is electrically connected to one terminal 42a and one end of the heating element 32. Wiring 42c extends in the X direction and is electrically connected to the other terminal 42a and the other end of the heating element 32.

[0032] The pair of terminals 41a and the pair of terminals 42a are electrically connected to, for example, a controller 210 (described later) via connectors and wiring.

[0033] The wiring section 41 and the wiring section 42 are formed using materials such as silver or copper. For example, the wiring section 41 can be formed by applying a paste-like material onto the insulating layer 21 using a screen printing method or the like, and then curing it using a firing method or the like. For example, the wiring section 42 can be formed by applying a paste-like material onto the insulating layer 22 using a screen printing method or the like, and then curing it using a firing method or the like.

[0034] The protective section 50 is provided on the insulating layer 20. The protective section 50 includes a protective section 51 provided on the insulating layer 21 and a protective section 52 provided on the insulating layer 22.

[0035] As shown in Figure 1, the protective part 51 extends in the X direction and covers the heating element 31, wiring 41b, and wiring 41c. In this case, the pair of terminals 41a are exposed from the protective part 51. The protective part 51 has functions such as insulating the heating element 31, wiring 41b, and wiring 41c, transferring heat generated in the heating element 31, and protecting the heating element 31, wiring 41b, and wiring 41c from external forces, corrosive gases, etc.

[0036] The protective section 52 extends in the X direction and covers the heating element 32, wiring 42b, and wiring 42c. In this case, the pair of terminals 42a are exposed from the protective section 52. The protective section 52 has functions such as insulating the heating element 32, wiring 42b, and wiring 42c, transmitting heat generated in the heating element 32, and protecting the heating element 32, wiring 42b, and wiring 42c from external forces, corrosive gases, etc.

[0037] The protective parts 51 and 52 are formed from materials that have heat resistance and insulating properties, as well as high chemical stability and thermal conductivity. For example, the protective parts 51 and 52 are formed from ceramics or glass. In this case, the protective parts 51 and 52 can also be formed 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.

[0038] The protective parts 51 and 52 can be formed by applying a paste-like material onto the insulating layers 21 and 22 using a screen printing method or the like, and then curing it using a firing method or the like.

[0039] Furthermore, the heater 1 may be further provided with a detection unit for detecting the temperature of the heat-generating section 30. 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 30 is provided, and on the side of the substrate 10 opposite to the side where the heat-generating section 30 is provided.

[0040] 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 50 is formed from, for example, ceramics, glass, or glass with fillers added. The insulating layer 20 is formed from, for example, an inorganic material such as ceramics.

[0041] Therefore, the thermal expansion coefficient of the substrate 10 differs from that of the protective part 50 and the insulating layer 20. Also, when the heater 1 is used and the heating element 30 (heating elements 31 and 32) is heated, the substrate 10, the protective part 50, and the insulating layer 20 are heated. When the heater 1 is manufactured and the protective part 50 and the insulating layer 20 are fired, the substrate 10, the protective part 50, and the insulating layer 20 are heated. Therefore, thermal stress is generated during the use and manufacture of the heater 1 due to the difference in the thermal expansion coefficients of the materials. When thermal stress is generated, there is a risk that the heater 1 may warp.

[0042] In this case, as shown in Figure 1, the X-direction dimension of the substrate 10 is longer than the Y-direction dimension of the substrate 10. Also, as mentioned above, the thickness of the substrate 10 is thin, for example, about 0.5 mm to 1.0 mm. Therefore, when thermal stress occurs, the substrate 10 is prone to warping, causing it to curve when viewed from the Y-direction. If the warping of the heater 1 becomes large, the distance between the heater 1 and the object to be heated will vary, which may cause uneven heating of the object.

[0043] Therefore, as shown in Figures 1 and 2, the substrate 10 is provided with a protrusion 10c. The protrusion 10c is provided on the side of the substrate 10 opposite to the side where the insulating layer 20, heating element 30, wiring element 40, and protective element 50 are provided. The protrusion 10c protrudes from the surface 10b of the substrate 10. The protrusion 10c can be formed integrally with the substrate 10, for example.

[0044] As shown in Figure 2, 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, 0.25 mm or more and 1.0 mm or less.

[0045] If the protrusion 10c is provided, the bending rigidity of the substrate 10 can be increased, so even if thermal stress occurs due to the difference in the thermal expansion coefficients of the materials, it is possible to suppress the occurrence of large warping that would cause the substrate 10 to bend when viewed from the Y direction.

[0046] Furthermore, if the distance H is between 0.25 mm and 1.0 mm, the protrusion 10c can be used to position the heater 1 when attaching it to the stay 201, etc., as described later, and a large gap between the heater 1 and the stay 201, etc., can be suppressed. In addition, a large warp in the substrate 10 when thermal stress occurs can be suppressed.

[0047] Furthermore, if the type of the stay 201 to which the heater 1 is attached changes, it may be necessary to adjust the shape of the substrate 10 when viewed from the X direction. As shown in Figures 1 and 2, a recess 10d is provided in the central part of the substrate 10 in the Y direction, so the shape of the substrate 10 can be adjusted by bending the substrate 10 around the recess 10d.

[0048] Figures 3(a) and 3(b) are schematic cross-sectional views illustrating the adjustment of the shape of the substrate 10. As shown in Figure 3(a), if a recess 10d is provided, it becomes easy to adjust the shape of the substrate 10 in a direction that brings the heating elements 31 and 32 closer together, with the recess 10d as the center. As shown in Figure 3(b), if a recess 10d is provided, it becomes easy to adjust the shape of the substrate 10 in a direction that separates the heating elements 31 and 32 with respect to the recess 10d.

[0049] In this case, as shown in Figure 2, the distance H1 (depth of the recess 10d) between the bottom of the recess 10d and the surface 10a of the substrate 10 can be, for example, 0.25 mm or more and 1.0 mm or less. If the distance H1 is 0.25 mm or more and 1.0 mm or less, it becomes easier to adjust the shape of the substrate 10, and it is possible to suppress large changes in the shape of the substrate 10 when thermal stress occurs.

[0050] Furthermore, as mentioned above, when viewed from the Z direction, the recess 10d is positioned to overlap with the protrusion 10c. For example, the center line of the recess 10d extending in the X direction can be made to overlap with the center line of the protrusion 10c extending in the X direction. Such protrusions 10c and recesses 10d can be integrally formed, for example, by press working. Therefore, even when the protrusions 10c and recesses 10d are provided on the substrate 10, manufacturing costs can be reduced.

[0051] Furthermore, the insulating layer 21, heating element 31, wiring section 41, and protective section 51 are provided on one side of the substrate 10, with the recess 10d in between. The insulating layer 22, heating element 32, wiring section 42, and protective section 52 are provided on the other side of the substrate 10, with the recess 10d in between. Therefore, even if the substrate 10 is bent around the recess 10d, damage to the insulating layer 21, heating element 31, wiring section 41, protective section 51, insulating layer 22, heating element 32, wiring section 42, and protective section 52 can be suppressed.

[0052] Figure 4 is a schematic front view illustrating a heater 11 according to another embodiment. Figure 4 shows the heater 11 as viewed from the side where the heating element 30a is located, in the Z direction. Figure 5 is a schematic cross-sectional view of the heater 11 in the direction of line BB in Figure 4. As shown in Figures 4 and 5, the heater 11 includes, for example, a substrate 60, an insulating layer 20a, a heating element 30a, a wiring element 40a, and a protective element 50a.

[0053] The substrate 60 is plate-shaped and has a surface 60a (corresponding to an example of a first surface) and a surface 60b (corresponding to an example of a second surface) opposite to surface 60a. Furthermore, a convex portion 60c and a concave portion 60d are provided in the central part of the substrate 60 in the Y direction. For example, the substrate 60 can be made by replacing the convex portion 10c and concave portion 10d of the aforementioned substrate 10 with a convex portion 60c and a concave portion 60d.

[0054] The protrusions 60c and recesses 60d can be the same as those described above for the protrusions 10c and recesses 10d. However, as shown in Figure 4, when viewed from the Z direction, a flat region is provided near the edge of the substrate 60 in the X direction. In the X direction, the edges of the protrusions 60c and recesses 60d are located closer to the center of the substrate 60 than the flat region.

[0055] Furthermore, the height Ha of the protrusion 60c can be the same as the height H of the protrusion 10c described above. The depth H1a of the recess 60d can be the same as the depth H1 of the recess 10d described above.

[0056] The insulating layer 20a is provided on the surface 60a of the substrate 60 where the recess 60d opens. The insulating layer 20a can be the same as the insulating layer 20 described above. However, the insulating layer 20a is also provided in a flat area near the edge of the substrate 60.

[0057] The heating element 30a is provided on the insulating layer 20a. The heating element 30a can be the same as the heating element 30 described above. However, the heating element 30a is provided with two heating elements 31. In addition, different heating elements may be provided, similar to the heating element 30 described above.

[0058] The wiring section 40a is provided on the insulating layer 20a. The material and formation method of the wiring section 40a can be the same as those of the wiring section 40 described above. The wiring section 40a has, for example, terminals 40a1, 40a2, 40a3, wiring 40a4, wiring 40a5, and wiring 40a6. Terminals 40a1, 40a2, and 40a3 are electrically connected to, for example, a controller 210, which will be described later, via connectors and wiring.

[0059] In the X direction, terminals 40a1 and 40a3 are located near one end of the substrate 60, and terminal 40a2 is located near the other end of the substrate 60. Wiring 40a4 is electrically connected to terminal 40a1 and one of the heating elements 31. Wiring 40a5 is electrically connected to terminal 40a2 and both of the heating elements 31. Wiring 40a6 is electrically connected to terminal 40a3 and the other heating element 31.

[0060] In this way, by selecting the terminal to which power is applied, the two heating elements 31 can be connected in series, the two heating elements 31 can be connected in parallel, or power can be applied to any one of the heating elements 31. In other words, the heating state of the heater 11 can be controlled by selecting the terminal to which power is applied.

[0061] For example, by selecting terminals 40a1 and 40a3, two heating elements 31 can be connected in series. For example, by selecting terminals 40a1 and 40a3 and terminal 40a2, two heating elements 31 can be connected in parallel. For example, by selecting either terminal 40a1 or 40a3 and terminal 40a2, power can be applied to either one of the heating elements 31.

[0062] The protective portion 50a is provided on the insulating layer 20a. The protective portion 50a extends in the X direction and covers the two heating elements 31, wiring 40a4, wiring 40a5, and wiring 40a6. In this case, terminals 40a1, 40a2, and 40a3 are exposed from the protective portion 50a. The recess 60d is also exposed from the protective portion 50a. The material and forming method of the protective portion 50a can be the same as, for example, the material and forming method of the protective portion 50 described above.

[0063] In the heater 11 according to this embodiment, the protrusion 60c is provided, which increases the bending rigidity of the substrate 60. Therefore, even if thermal stress occurs due to the difference in the thermal expansion coefficients of the materials, it is possible to suppress the occurrence of large warping that would cause the substrate 60 to bend when viewed from the Y direction.

[0064] Furthermore, if the distance Ha is between 0.25 mm and 1.0 mm, the protrusion 60c can be used to position the heater 11 when attaching it to the stay 201, etc., as described later, and a large gap between the heater 11 and the stay 201, etc., can be suppressed. In addition, a large warp in the substrate 60 when thermal stress occurs can be suppressed.

[0065] Furthermore, when viewed from the Z direction, the recess 60d is positioned to overlap with the protrusion 60c. For example, the center line of the recess 60d extending in the X direction can be made to overlap with the center line of the protrusion 60c extending in the X direction. Such protrusions 60c and recesses 60d can be integrally formed, for example, by press working. Therefore, even when the protrusions 60c and recesses 60d are provided on the substrate 60, manufacturing costs can be reduced.

[0066] (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 description of the heater 1 and its variations (e.g., heater 11) can all be applied to the image forming apparatus 100.

[0067] 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.

[0068] Figure 6 is a schematic diagram illustrating the image forming apparatus 100 according to this embodiment. Figure 7 is a schematic diagram illustrating the fixing section 200. As shown in Figure 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 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.

[0069] 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.

[0070] 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.

[0071] 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.

[0072] 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.

[0073] The charging unit 150, the discharge unit 151, the developing unit 160, and the cleaner 170 are located around the photosensitive drum 140.

[0074] 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.

[0075] 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.

[0076] The fixing unit 200 is located downstream of the photosensitive drum 140 (on the tray 182 side). As shown in Figure 7, the fixing unit 200 includes, for example, a heater 1(11), a stay 201, a film belt 202, and a pressure roller 203.

[0077] A heater 1(11) is attached to the stay 201 on the side facing the paper 510 transport line. The heater 1(11) can be embedded in the stay 201. In this case, the side of the heater 1(11) with the protective part 50(50a) is exposed from the stay 201.

[0078] The film belt 202 covers the stay 201 on which the heater 1(11) is provided. The film belt 202 may include a heat-resistant resin such as polyimide.

[0079] 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.

[0080] 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.

[0081] 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.

[0082] The following are additional notes regarding the embodiments described above.

[0083] (Note 1) A substrate having a plate-like shape, containing metal, having a first surface and a second surface opposite the first surface, and 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 aforementioned heating element; It is equipped with, The aforementioned substrate is A convex portion provided on the second surface and extending in the first direction; A recess opening into the first surface and extending in the first direction; It has, When viewed from a second direction intersecting the first surface, the recessed portion of the heater overlaps with the convex portion.

[0084] (Note 2) The heater according to Appendix 1, wherein the recess is further open at one end and the other end of the substrate in the first direction.

[0085] (Note 3) The heater according to Appendix 1, wherein, when viewed from the second direction, a flat region is provided near the edge of the substrate in the first direction, and the ends of the convex portion and the concave portion are located closer to the center of the substrate than the flat region.

[0086] (Note 4) An image forming apparatus equipped with a heater as described in any one of the appendices 1 to 3. [Explanation of symbols]

[0087] 1 Heater, 10 Substrate, 10a surface, 10b surface, 10c protrusion, 10d recess, 11 Heater, 20 Insulating layer, 20a Insulating layer, 21 Insulating layer, 22 Insulating layer, 30 Heating part, 31 Heating element, 32 Heating element, 50 Protective part, 50a Protective part, 51 Protective part, 52 Protective part, 60 Substrate, 60a surface, 60b surface, 60c protrusion, 60d recess, 100 Image forming apparatus, 200 Fixing part

Claims

1. A substrate having a plate-like shape, containing metal, having a first surface and a second surface opposite to the first surface, and 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; It is equipped with, The aforementioned substrate is A convex portion provided on the second surface and extending in the first direction; A recess opening into the first surface and extending in the first direction; It has, When viewed from a second direction intersecting the first surface, the recessed portion of the heater overlaps with the convex portion.

2. The heater according to claim 1, wherein the recess is further open to one end and the other end of the substrate in the first direction.

3. The heater according to claim 1, wherein, when viewed from the second direction, a flat region is provided near the edge of the substrate in the first direction, and the end of the convex portion and the end of the concave portion are located closer to the center of the substrate than the flat region.

4. An image forming apparatus comprising the heater described in claim 1.

Images