Heater and image forming apparatus

Abstract

To provide a heater that can increase the rigidity of a base including metal and can prevent the occurrence of warpage, and an image forming apparatus.SOLUTION: A heater according to an embodiment is provided with: a base 10 that has a first portion 10a that exhibits a plate shape and extends in a first direction, and a second portion 10b that exhibits the plate shape, extends in the first direction, and is connected to the periphery of the first portion in a second direction orthogonal to the first direction, and that includes metal; a first heating unit 20 that is provided at the first portion and has a first heating element extending in the first direction; and a second heating unit 30 that is provided at the second portion and has a second heating element extending in the first direction.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. Generally, such a heater has a plate-shaped base extending in one direction, a heating element provided on one surface of the base, and a protective part provided on one surface of the base to cover the heating element.

[0003] The base is made of a material having heat resistance, insulation, and high thermal conductivity. In this case, if the material of the base is metal, the rigidity of the base can be improved and the manufacturing cost can be reduced. The protective part is made of a material having heat resistance, insulation, high thermal conductivity, and high chemical stability. For example, the protective part is made of an inorganic material such as ceramics or glass.

[0004] Here, when the material of the base and the material of the protective part are different, thermal stress is generated due to the difference in the thermal expansion coefficients of the materials. In this case, since the difference between the thermal expansion coefficient of metal and the thermal expansion coefficient of an inorganic material such as ceramics is large, the generated thermal stress tends to be large. When the thermal stress becomes large, the warp of the heater becomes large, and the distance between the heater and the object to be heated tends to vary. Therefore, when the warp of the heater becomes large, there is a possibility that uneven heating occurs in the object to be heated.

[0005] In this case, it may be considered that the warp of the heater can be suppressed by bending the plate-shaped base to increase its rigidity. However, if this is done, the bent portion of the base becomes a heat dissipation fin, and a temperature distribution is likely to occur in the base. Therefore, the warp of the base may rather increase.

[0006] Therefore, development of a technology that can increase the rigidity of a base containing metal and suppress the occurrence of warping 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 increase the rigidity of a base containing metal and suppress the occurrence of warping.

Means for Solving the Problems

[0009] The heater according to the embodiment has a first portion that is plate-shaped and extends in a first direction, and a second portion that is plate-shaped, extends in the first direction, and is connected to a periphery of the first portion in a second direction orthogonal to the first direction, and includes a base containing metal; a first heating portion provided in the first portion and having a first heating element that extends in the first direction; and a second heating portion provided in the second portion and having a second heating element that extends in the first direction.

Effects 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 increase the rigidity of a base containing metal and suppress the occurrence of warping.

Brief Description of the Drawings

[0011]

Figure 1

Figure 2

Figure 3

Figure 4

Figure 5

Figure 6

Figure 7

Mode for Carrying Out the Invention

[0012] Hereinafter, embodiments will be exemplified with reference to the drawings. In each drawing, the same reference numerals are given to the same components and detailed descriptions 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 base is the X direction (corresponding to an example of the first direction), the short side direction (width direction) of the base is the Y direction (corresponding to an example of the second direction), and the direction perpendicular to the surface of the base where the heat generating portion is provided is the Z direction.

[0013] (Heater) FIG. 1 is a schematic front view for exemplifying the heater 1 according to the present embodiment. Note that FIG. 1 is a view of the heater 1 seen from the side where the heat generating portion 20 (corresponding to an example of the first heat generating portion) is provided. FIG. 2 is a schematic cross-sectional view in the direction of line A-A of the heater 1 in FIG. 1. As shown in FIGS. 1 and 2, the heater 1 has, for example, a base 10, a heat generating portion 20, and a heat generating portion 30 (corresponding to an example of the second heat generating portion).

[0014] As shown in FIG. 2, the base 10 has a plate shape and includes a first portion 10a extending in the X direction and a second portion 10b also having a plate shape, extending in the X direction and connected to the Y-direction periphery of the first portion 10a. As shown in FIG. 2, the second portion 10b can be provided at the Y-direction peripheries on both sides of the first portion 10a, or can be provided at the Y-direction periphery on one side of the first portion 10a. When the second portion 10b is provided at the Y-direction peripheries on both sides of the first portion 10a, the two second portions 10b are provided on the same side of the first portion 10a in the Z direction.

[0015] The shape of the first portion 10a as viewed from the Z direction is, for example, an elongated rectangle. The shape of the second portion 10b as viewed from the Y direction is, for example, an elongated rectangle. The length of the second portion 10b in the X direction can be the same as or different from the length of the first portion 10a in the X direction. In the base 10 illustrated in FIG. 1, the length of the second portion 10b in the X direction is the same as the length of the first portion 10a in the X direction.

[0016] When the second portion 10b is provided at the Y-direction peripheries on both sides of the first portion 10a, the lengths of the two second portions 10b in the Z direction can be the same or different. In the base 10 illustrated in FIG. 2, the lengths of the two second portions 10b in the Z direction are the same.

[0017] The thickness of the second portion 10b can be the same as or different from the thickness of the first portion 10a. Also, when the second portion 10b is provided at the Y-direction peripheries on both sides of the first portion 10a, the thicknesses of the two second portions 10b can be the same or different. In the base 10 illustrated in FIG. 2, the thickness of the first portion 10a and the thicknesses of the two second portions 10b are the same. The thickness of the first portion 10a and the thicknesses of the two second portions 10b are, for example, about 0.5 mm to 1.0 mm.

[0018] The dimensions of the first portion 10a in the X direction and the dimensions of the first portion 10a in the Y direction can be appropriately changed according to, for example, the size of the object to be heated (such as paper). The dimensions of the second portion 10b in the Z direction can be the same as or different from the dimensions of the first portion 10a in the Y direction. In the base 10 illustrated in FIG. 2, the dimensions of the second portion 10b in the Z direction are smaller than the dimensions of the first portion 10a in the Y direction. By doing so, it is possible to suppress an increase in the Z - direction dimension of the heater 1.

[0019] The angle between the first portion 10a and the second portion 10b may be 90°, less than 90°, or greater than 90°. In the base 10 illustrated in FIG. 2, the angle between the first portion 10a and the second portion 10b is 90°. In this case, if the angle between the first portion 10a and the second portion 10b is 90° or less, the tip of the second portion 10b does not protrude laterally in the Y direction of the first portion 10a, so it is possible to suppress an increase in the Y - direction dimension of the heater 1. Also, if the angle between the first portion 10a and the second portion 10b is less than 90°, it is possible to suppress an increase in the Z - direction dimension of the heater 1.

[0020] The base 10 is formed of a material having heat resistance and high thermal conductivity. The base 10 is formed of, for example, a metal such as stainless steel or an aluminum alloy. For example, the first portion 10a and the second portion 10b can be integrally formed. For example, the base 10 can be formed by plastic working such as bending or pressing, or drawing.

[0021] The thermal conductivity of a metal is higher than that of an inorganic material such as ceramics. Therefore, if the base 10 is formed of a metal, it is possible to suppress the occurrence of an in - plane distribution in the temperature of the heater 1. Also, it is possible to improve the rigidity of the base 10 and reduce the manufacturing cost.

[0022] The heating part 20 is provided on the first part 10a of the base part 10. The heating part 20 is provided on the surface 10a1 of the first part 10a on the side opposite to the side where the second part 10b is provided. The heating part 20 extends in the X direction. As shown in FIGS. 1 and 2, the heating part 20 has, for example, an insulating layer 21, a heating element 22 (corresponding to an example of a first heating element), a wiring part 23, and a protection part 24.

[0023] The insulating layer 21 is provided on the surface 10a1 of the first part 10a. The insulating layer 21 is provided between the first part 10a and the heating element 22 and the wiring part 23, and insulates the first part 10a from the heating element 22 and the wiring part 23. The insulating layer 21 is formed of a material having heat resistance and insulation properties. The insulating layer 21 can be formed of, for example, an inorganic material such as ceramics. The thickness of the insulating layer 21 is not particularly limited as long as the first part 10a can be insulated from the heating element 22 and the wiring part 23.

[0024] The heating element 22 converts the applied electric power into heat (Joule heat). The heating element 22 extends in the X direction, for example. In FIGS. 1 and 2, as an example, the case where one heating element 22 is provided is illustrated, but the number and size of the heating elements 22 can be appropriately changed according to the size of the surface 10a1 of the first part 10a and the size of the object to be heated, etc. Also, a plurality of types of heating elements 22 having different lengths, widths, shapes, etc. can be provided. That is, at least one heating element 22 may be provided.

[0025] When providing a plurality of heating elements 22, for example, the plurality of heating elements 22 can be arranged side by side at a predetermined interval in the Y direction. The dimensions of the plurality of heating elements 22 in the X direction can be the same or different. In this case, it is preferable that the centers of the plurality of heating elements 22 are located on the straight line 1a. That is, it is preferable that each of the plurality of heating elements 22 has a shape that is line-symmetric with the straight line 1a as the axis of symmetry.

[0026] When attaching the heater 1 to the image forming apparatus 100, for example, the straight line 1a is made to overlap the center line of the conveyance path of the object to be heated. By doing so, even when the dimension of the object to be heated in the direction orthogonal to the conveyance direction changes, the object to be heated can be heated substantially uniformly.

[0027] When providing a plurality of heating elements 22, the electrical resistance values (heating amounts) of the plurality of heating elements 22 can be the same or different. For example, by making the dimensions in the X direction (length dimension), Y direction (width dimension), and Z direction (thickness) of the plurality of heating elements 22 the same respectively, the electrical resistance values of the plurality of heating elements 22 can be made the same. Also, by changing at least any one of these dimensions, the electrical resistance values of the plurality of heating elements 22 can be made different. Further, by changing the material, the electrical resistance values of the plurality of heating elements 22 can be made different.

[0028] Also, the electrical resistance value per unit length of the heating element 22 can be made uniform in the X direction. For example, the dimensions in the Y direction (width dimension) and Z direction (thickness) of the heating element 22 can be made constant. The shape of the heating element 22 as viewed from the Z direction can be, for example, a rectangle extending in the X direction.

[0029] The heating element 22 can be formed using, for example, ruthenium oxide (RuO2), a silver - palladium (Ag - Pd) alloy, etc. The heating element 22 can be formed, for example, by applying a paste - like material onto the insulating layer 21 using a screen printing method or the like and curing it using a firing method or the like.

[0030] The wiring portion 23 is provided on the insulating layer 21. The wiring portion 23 has, for example, terminals 23a, terminals 23b, wiring 23c, and wiring 23d. The terminals 23a and the terminals 23b are electrically connected to the controller 210 of the image forming apparatus 100, for example, via a connector and wiring.

[0031] The terminal 23a is provided, for example, near one end of the base 10 in the X direction. The wiring 23c is electrically connected to, for example, one end of the heating element 22 in the X direction and the terminal 23a. The terminal 23b is provided, for example, near the other end of the base 10 in the X direction. The wiring 23d is electrically connected to, for example, the other end of the heating element 22 in the X direction and the terminal 23b.

[0032] The wiring portion 23 (the terminal 23a, the terminal 23b, the wiring 23c, and the wiring 23d) is formed using, for example, a material containing silver, copper, or the like. For example, the terminal 23a, the terminal 23b, the wiring 23c, and the wiring 23d can be formed by applying a paste-like material onto the insulating layer 21 using a screen printing method or the like and curing it using a firing method or the like.

[0033] The protection portion 24 is provided on the insulating layer 21 and covers the heating element 22 and a part of the wiring portion 23 (the wiring 23c and the wiring 23d). In this case, the terminals 23a and 23b of the wiring portion 23 are exposed from the protection portion 24.

[0034] The protection portion 24 extends in the X direction. The protection portion 24 has, for example, a function of insulating a part of the heating element 22 and the wiring portion 23, a function of transmitting the heat generated in the heating element 22 to the outside, and a function of protecting a part of the heating element 22 and the wiring portion 23 from external force, corrosive gas, or the like. The protection portion 24 has heat resistance and insulation properties and is formed from a material having high chemical stability and high thermal conductivity. The protection portion 24 is formed from, for example, inorganic materials such as ceramics and glass. In this case, the protection portion 24 can also be formed using glass containing a filler having a high thermal conductivity such as aluminum oxide. The thermal conductivity of the glass with the filler added can be, for example, 2 [W / (m·K)] or more.

[0035] Further, the heater 1 can be further provided with a detection unit for detecting the temperature of the heating unit 20. The detection unit can be, for example, a thermistor or the like. The detection unit can be provided on at least one of the surface 10a1 side of the first portion 10a and the surface 10a2 side of the first portion 10a.

[0036] When the detection unit is provided on the surface 10a1 side of the first portion 10a, the detection unit, the wiring and terminals electrically connected to the detection unit can be provided on the insulating layer 21. The wiring electrically connected to the detection unit can be covered by the protection unit 24. The terminal electrically connected to the detection unit can be exposed from the protection unit 24.

[0037] When the detection unit is provided on the surface 10a2 side of the first portion 10a, an insulating layer can be provided on the surface 10a2, and the detection unit, the wiring and terminals electrically connected to the detection unit can be provided on the insulating layer. The insulating layer can be the same as the insulating layer 21. Also, the wiring electrically connected to the detection unit can be covered by the protection unit. The terminal electrically connected to the detection unit can be exposed from the protection unit. The protection unit can be the same as the protection unit 24 provided on the insulating layer 21.

[0038] Here, as described above, the base 10 is formed of a metal such as stainless steel or an aluminum alloy. On the other hand, the protection unit 24 is formed of, for example, an inorganic material such as ceramics, glass, or glass with a filler added. The insulating layer 21 is formed of, for example, an inorganic material such as ceramics.

[0039] Therefore, the coefficient of thermal expansion of the material of the base 10 is different from that of the materials of the protective part 24 and the insulating layer 21. Further, when the heating element 22 generates heat during the use of the heater 1, the base 10, the protective part 24, and the insulating layer 21 are heated. When the protective part 24 and the insulating layer 21 are fired during the manufacture of the heater 1, the base 10, the protective part 24, and the insulating layer 21 are heated. Therefore, thermal stress is generated due to the difference between the coefficient of thermal expansion of the material of the base 10 and the coefficients of thermal expansion of the materials of the protective part 24 and the insulating layer 21 during the use or manufacture of the heater 1. When thermal stress is generated, the heater 1 may be warped.

[0040] As described above, the base 10 is provided with a second portion 10b that intersects the first portion 10a. Therefore, the bending rigidity of the base 10 can be increased as compared with the case where only the plate-like first portion 10a is provided. It is also considered that if the bending rigidity of the base 10 is increased, warping of the heater 1 can be suppressed.

[0041] However, simply providing the second portion 10b may cause the second portion 10b to become a heat dissipation fin. When the second portion 10b becomes a heat dissipation fin, the difference between the temperature of the first portion 10a heated by the heating portion 20 and the temperature of the second portion 10b may increase, and conversely, the warping may increase. When the warping of the base 10 increases, the distance between the heater 1 and the object to be heated may vary, and uneven heating may occur in the object to be heated.

[0042] Therefore, as shown in FIGS. 1 and 2, a heating portion 30 is provided in the second portion 10b of the base 10. The heating portion 30 can be provided on at least one of the outer surface 10b1 and the inner surface 10b2 of the second portion 10b. The heating portion 30 illustrated in FIGS. 1 and 2 is provided on the outer surface 10b1 of the second portion 10b. In this case, if the heating portion 30 is provided on the outer surface 10b1 of the second portion 10b, the formation of the heating portion 30 becomes easy.

[0043] The heating portion 30 extends in the X direction. The heating part 30 has, for example, an insulating layer 31, a heating element 32 (corresponding to an example of the second heating element), a wiring part 33, and a protection part 34. The insulating layer 31 can be the same as the insulating layer 21 described above. Also, the insulating layer 31 can be formed integrally with the insulating layer 21. The heating element 32 extends in the X direction. The heating element 32 can be the same as the heating element 22 described above. The wiring part 33 can be the same as the wiring part 23 described above. The protection part 34 can be the same as the protection part 24 described above. Also, the detection part described above can be provided.

[0044] However, the respective dimensions of the insulating layer 31, the heating element 32, the wiring part 33, and the protection part 34 in the Z direction can be appropriately changed according to the dimension of the second part 10b in the Z direction. For example, the respective dimensions of the insulating layer 31, the heating element 32, the wiring part 33, and the protection part 34 in the Z direction, as illustrated in FIG. 2, are smaller than the respective dimensions of the insulating layer 21, the heating element 22, the wiring part 23, and the protection part 24 in the Y direction.

[0045] The heating element 32 is electrically connected to, for example, the controller 210 of the image forming apparatus 100 via a connector, wiring, etc. The controller 210 controls the voltage applied to the heating element 22 and the heating element 32 to control the temperature of the heating part 20 and the temperature of the heating part 30. In this case, when the detection part described above is provided, the controller 210 can perform feedback control of the temperature of the heating part 20 and the temperature of the heating part 30 based on the signal from the detection part.

[0046] If the heat generating part 30 is provided in the second part 10b, the second part 10b can be heated, so that the difference between the temperature of the first part 10a heated by the heat generating part 20 and the temperature of the second part 10b heated by the heat generating part 30 can be reduced. If the difference between the temperature of the first part 10a and the temperature of the second part 10b becomes smaller, the warpage of the base 10 can be reduced. Therefore, the rigidity of the base 10 containing metal can be increased, and the occurrence of warpage can be suppressed. If the occurrence of warpage can be suppressed, it is possible to suppress the variation in the distance between the heater 1 and the object to be heated and the generation of uneven heating on the object to be heated.

[0047] According to the findings obtained by the present inventors, if the heat generating part 30 is provided in the second part 10b and the second part 10b is heated, the warpage amount (mm) of the base 10 in the Z direction / the dimension (mm) of the base 10 in the X direction, which was about 5 / 400, could be reduced to 1 / 400 or less.

[0048] As described above, the heating element 22 and the heating element 32 are electrically connected to the controller 210. In this case, if the heating element 32 is connected in parallel with the heating element 22, it becomes easier for the controller 210 to control the heating element 22 and the heating element 32. However, if the heating element 32 is connected in parallel with the heating element 22, it becomes difficult for the controller 210 to control the heating element 22 and the heating element 32 individually.

[0049] Therefore, when the heating element 32 is connected in parallel with the heating element 22, the heat generation amount of the heating element 22 and the heat generation amount of the heating element 32 may be appropriately set so that the difference between the temperature of the first part 10a and the temperature of the second part 10b becomes smaller. For example, the heat generation amount of the heating element 22 and the heat generation amount of the heating element 32 can be appropriately set according to the ratio of the area of the surface 10a1 of the first part 10a to the area of the surface 10b1 of the second part 10b. For example, when the area of the surface 10b1 is about 1 / 4 of the area of the surface 10a1 and the power consumption of the heating element 22 is about 1000W, the power consumption of the heating element 32 can be about 250W.

[0050] The power consumption of the heating elements 22 and 32 can be adjusted, for example, according to the electrical resistance values of the heating elements 22 and 32. For example, if the electrical resistance values of the heating elements 22 and 32 are increased, the power consumption of the heating elements 22 and 32, and thus the heat generation amount of the heating elements 22 and 32, can be increased. For example, if the cross-sectional area of the heating elements 22 and 32 is reduced or the dimension in the extending direction of the heating elements 22 and 32 is increased, the electrical resistance values of the heating elements 22 and 32 can be increased. Also, the electrical resistance values of the heating elements 22 and 32 can be increased by changing the materials of the heating elements 22 and 32. The heat generation amount of the heating element 22 and the heat generation amount of the heating element 32 may be appropriately set, for example, by performing experiments or simulations so that the warping amount of the base 10 is minimized.

[0051] Further, the heat generated in the heating section 30 can also be used, together with the heat generated in the heating section 20, to heat the object to be heated. Therefore, if the heating section 30 is provided, the power consumption of the heating section 20 can be reduced. As a result, the service life of the heating section 20 (heating element 22) can be extended.

[0052] FIGS. 3(a) and 3(b) are schematic cross-sectional views for illustrating bases 11 and 12 according to other embodiments. As shown in FIG. 3(a), the angle θ1 between the first portion 11a and the second portion 11b may exceed 90°. The angle θ1 can be, for example, “90° < θ1 ≦ 160°”. As shown in FIG. 3(b), the angle θ2 between the first portion 12a and the second portion 12b may be less than 90°. The angle θ2 can be, for example, “20° ≦ θ2 < 90°”.

[0053] By doing so, it is possible to improve the bending rigidity of the bases 11 and 12 and suppress an increase in the dimension of the heater 1 in the Z direction. Also, if “20° ≦ θ2 < 90°”, when viewed from the Z direction, the tip of the second portion 12b is located inside the first portion 12a, so that it is possible to improve the bending rigidity of the base 12 and suppress an increase in the dimensions of the heater 1 in the Z direction and the Y direction. The angle between the first part and the second part can be appropriately changed according to, for example, the size and shape of the area where the heater 1 is attached in the image forming apparatus 100, etc.

[0054] Figs. 4(a) to 4(c) are schematic cross-sectional views for exemplifying bases 13 to 15 according to other embodiments. As shown in Figs. 4(a) to 4(c), the second parts 13b to 15b can also be provided on one side of the first parts 13a to 15a in the Y direction. Note that the angle θ3 between the first part 13a and the second part 13b in Fig. 4(a) is 90°. By doing so, the bases 13 to 15 can be made lighter and less costly. Also, since the number of heat generating parts 30 can be reduced, the heater can be made lighter and less costly.

[0055] Figs. 5(a) and 5(b) are schematic plan views for exemplifying heat generating parts according to other embodiments. As shown in Fig. 5(a), in the heat generating part 20a, the wiring 23d can be electrically connected to the first part 10a. In the heat generating part 30a, the wiring 33d can be electrically connected to the second part 10b. Also, in the heat generating part 20a, the terminal 23b of the wiring part can be omitted. In the heat generating part 30a, the terminal 33b of the wiring part can be omitted. That is, one end of the wiring can be electrically connected to the heating element on the insulating layer, and the other end of the wiring can be electrically connected to the base outside the insulating layer.

[0056] Also, as shown in Fig. 5(b), in the heat generating part 20b, the heating element 22 can be electrically connected to the first part 10a. In the heat generating part 30b, the heating element 32 can be electrically connected to the second part 10b. That is, one end of the heating element can be electrically connected to the base outside the insulating layer.

[0057] By doing so, the base 10 formed of metal can be provided with the functions of wiring and terminals. Therefore, for example, on one side of the base 10 in the X direction, electrical connection with the image forming apparatus 100 can be made by a connector and wiring. As a result, the wiring work between the heater and the image forming apparatus 100 becomes easy.

[0058] (Image forming apparatus) In one embodiment of the present invention, an image forming apparatus 100 including a heater 1 can be provided. The above-described explanations regarding the heater 1 and the modified examples of the heater 1 (for example, the bases 11 to 15, the heating portions 20a, 20b, 30a, 30b, etc. described above) can all be applied to the image forming apparatus 100.

[0059] Also, hereinafter, 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.

[0060] 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.

[0061] The frame 110 has a box shape and houses therein the illumination unit 120, the imaging element 130, the photosensitive drum 140, the charging unit 150, the developing unit 160, the cleaner 170, a part of the storage unit 180, the conveying unit 190, the fixing unit 200, and the controller 210. On the upper surface of the frame 110, a window 111 made of a light-transmitting material such as glass can be provided. On the window 111, the document 500 to be copied is placed. Also, a moving unit for moving the position of the document 500 can be provided.

[0062] The illumination unit 120 is provided near the window 111. The illumination unit 120 has, for example, a light source 121 such as a lamp and a reflecting mirror 122. The pixel forming element 130 is provided near the window 111. The photosensitive drum 140 is provided below the illumination unit 120 and the pixel forming 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.

[0063] 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 the copied image 511a is fixed is stored.

[0064] The conveying unit 190 is provided below the photosensitive drum 140. The conveying unit 190 conveys the paper 510 between the cassette 181 and the tray 182. The conveying unit 190 has, for example, a guide 191 for supporting the conveyed paper 510 and conveying rollers 192 to 194 for conveying the paper 510. Also, a motor for rotating the conveying rollers 192 to 194 can be provided in the conveying unit 190.

[0065] The fixing unit 200 is provided on the downstream side (the tray 182 side) 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. A heater 1 is attached to the conveyance line side of the platen 201 for the paper 510. The heater 1 can be embedded in the platen 201. In this case, the side of the heater 1 where the protection part 24 is provided is exposed from the platen 201.

[0066] The film belt 202 covers the platen 201 where the heater 1 is provided. The film belt 202 can contain a resin having heat resistance such as polyimide, for example.

[0067] The pressure roller 203 is provided so as to face the platen 201. The pressure roller 203 has, for example, a mandrel 203a, a drive shaft 203b, and an elastic part 203c. The drive shaft 203b protrudes from the end of the mandrel 203a and is connected to a drive device such as a motor. The elastic part 203c is provided on the outer surface of the mandrel 203a. The elastic part 203c is formed from an elastic material having heat resistance. The elastic part 203c can contain, for example, a silicone resin or the like.

[0068] 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, an abnormality display, and the like. Note that since known techniques can be applied to the control of each element provided in the image forming apparatus 100, detailed description thereof is omitted.

[0069] As mentioned 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 included in the invention described in the claims and the equivalent scope thereof. Also, the above-described embodiments can be implemented in combination with each other.

[0070] The following shows the supplementary notes regarding the above-described embodiments.

[0071] (Supplementary Note 1) A base including a metal, having a first portion presenting a plate shape and extending in a first direction, and a second portion presenting a plate shape, extending in the first direction, and connected to a periphery of the first portion in a second direction orthogonal to the first direction; A first heating portion provided on the first portion and having a first heating element extending in the first direction; A second heating portion provided on the second portion and having a second heating element extending in the first direction; A heater comprising the above.

[0072] (Supplementary Note 2) The heater according to Supplementary Note 1, wherein the second heating element is connected in parallel with the first heating element.

[0073] (Supplementary Note 3) The first heating portion An insulating layer provided between the first portion and the first heating element; A wiring having one end electrically connected to the first heating element on the insulating layer and the other end electrically connected to the first portion outside the insulating layer; The heater according to Supplementary Note 1 or 2, having the above.

[0074] (Supplementary Note 4) The first heating part has an insulating layer provided between the first part and the first heating element. One end of the first heating element is electrically connected to the first part outside the insulating layer. The heater according to appended note 1 or 2.

[0075] (Appended note 5) An image forming apparatus including the heater according to any one of appended notes 1 to 4.

Explanation of reference numerals

[0076] 1 Heater, 10 Base, 10a First part, 10b Second part, 20 Heating part, 21 Insulating layer, 22 Heating element, 30 Heating part, 32 Heating element, 100 Image forming apparatus, 200 Fixing part

Claims

1. A base having a first portion presenting a plate shape and extending in a first direction, and a second portion presenting a plate shape, extending in the first direction, and connected to a periphery of the first portion in a second direction orthogonal to the first direction, and containing a metal; A first heating part provided on the first portion and having a first heating element extending in the first direction; A second heating part provided on the second portion and having a second heating element extending in the first direction; A heater comprising the above.

2. The heater according to Claim 1, wherein the second heating element is connected in parallel with the first heating element.

3. The first heating part includes An insulating layer provided between the first portion and the first heating element; Wiring having one end electrically connected to the first heating element on the insulating layer and the other end electrically connected to the first portion outside the insulating layer; The heater according to Claim 1 or 2 having the above.

4. The first heating part has an insulating layer provided between the first portion and the first heating element, The heater according to Claim 1 or 2, wherein one end of the first heating element is electrically connected to the first portion outside the insulating layer.

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

Images