JP2023072316A - Heater and image forming apparatus - Google Patents

Abstract

To provide a heater and an image forming apparatus that can increase the distance between an end in a short direction of a substrate and an end in the short direction of a heating element.SOLUTION: A heater according to an embodiment is provided with: a substrate that is formed of metal and has a shape extending in one direction; a first insulating part that is provided on a first surface of the substrate and has insulating properties; at least one first heating element that is provided on the first insulating part and extends along a longitudinal direction of the substrate; and a first protection part that is provided on the first insulating part, extends along the longitudinal direction of the substrate, and covers the first heating element. The distance between an end in a short direction of the substrate and an end in the short direction of the first heating element is 1.5 mm or more.SELECTED DRAWING: Figure 2

Description

Embodiments of the present invention relate to heaters and image forming apparatuses.

2. Description of the Related Art Image forming apparatuses such as copiers and printers are provided with heaters for fixing toner. Generally, such a heater has an elongated 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.

Generally, the substrate is made of a material that has heat resistance, insulation, and high thermal conductivity. For example, the substrate is made of ceramics such as aluminum oxide.
The heating element is made of, for example, a palladium alloy.
The protective portion is made of a material having heat resistance, insulation, high thermal conductivity, and high chemical stability. For example, the protection part is made of ceramics, glass material, or the like.

Here, in the case of the heater used in the image forming apparatus, the width dimension (dimension in the lateral direction) of the substrate is set within a predetermined range. Therefore, if it is possible to increase the distance between the edge in the short direction of the substrate (end on the long side) and the edge in the short direction of the heating element (end on the long side), The body width dimension (transverse dimension) can be reduced. If the width dimension of the heat generating element is reduced, the volume of the heat generating element can be reduced, so that the material cost of the heat generating element can be reduced.

However, when the distance between the lateral end of the substrate and the lateral end of the heating element increases, the temperature in the vicinity of the edge of the substrate and the temperature of the portion of the substrate where the heating element is provided increase. A large difference in temperature may cause cracks in a substrate made of ceramics.
Therefore, it has been desired to develop a technique capable of increasing the distance between the short-side end of the substrate and the short-side end of the heating element.

Japanese Patent Application Laid-Open No. 2007-240606

A problem to be solved by the present invention is to provide a heater and an image forming apparatus capable of increasing the distance between the lateral end of a substrate and the lateral end of a heating element. is.

A heater according to an embodiment includes: a substrate formed of metal and having a shape extending in one direction; a first insulating portion provided on a first surface of the substrate and having insulating properties; and the first insulating at least one first heating element provided on the portion extending along the longitudinal direction of the substrate; and at least one first heating element provided on the first insulating portion extending along the longitudinal direction of the substrate and extending along the longitudinal direction of the substrate. and a first protection part covering one heating element. The distance between the lateral end of the substrate and the lateral end of the first heating element is 1.5 mm or more.

According to the embodiments of the present invention, it is possible to provide a heater and an image forming apparatus capable of increasing the distance between the lateral end of the substrate and the lateral end of the heating element. can.

FIG. 3 is a schematic front view for illustrating the heater according to the embodiment; FIG. 2 is a schematic cross-sectional view of the heater in the direction of line AA in FIG. 1; It is a schematic cross section of the heater which concerns on other embodiment. It is a schematic cross section of the heater which concerns on other embodiment. 1 is a schematic diagram illustrating an image forming apparatus according to an exemplary embodiment; FIG. 4 is a schematic diagram for illustrating a fixing section; FIG.

Hereinafter, embodiments will be illustrated with reference to the drawings. In addition, in each drawing, the same reference numerals are given to the same constituent elements, and detailed description thereof will be omitted as appropriate. Arrows X, Y, and Z in each drawing represent three directions orthogonal to each other. For example, the longitudinal direction of the substrate is the X direction, the lateral direction (width direction) of the substrate is the Y direction, and the direction perpendicular to the surface of the substrate is the Z direction.

(heater)
FIG. 1 is a schematic front view for illustrating a heater 1 according to this embodiment.
FIG. 2 is a schematic cross-sectional view of the heater 1 in FIG. 1 taken along line AA.
As shown in FIGS. 1 and 2, the heater 1 includes, for example, a substrate 10, an insulating portion 20 (corresponding to an example of a first insulating portion), and a heating element 30 (corresponding to an example of a first heating element). , a wiring portion 40 , a protection portion 50 (corresponding to an example of a first protection portion), and a relaxation portion 60 .

The substrate 10 has a plate shape 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) facing the surface 10a. The substrate 10 has a shape extending in one direction (for example, the X direction). The planar shape of the substrate 10 is, for example, an elongated rectangle. The thickness of the substrate 10 is, for example, approximately 0.5 mm to 1.0 mm. The width dimension W (transverse dimension; Y direction dimension) of the substrate 10 is, for example, about 5 mm to 15 mm. The length (dimension in the longitudinal direction; dimension in the X direction) of the substrate 10 can be appropriately changed according to the size of the object to be heated (for example, paper).

The substrate 10 is made of a material having heat resistance and high thermal conductivity. Substrate 10 is generally made of ceramics such as aluminum oxide, but substrate 10 made of metal is used for heater 1 according to the present embodiment. The metal can be, for example, stainless steel, an aluminum alloy, or the like. Details of the function and effect of the substrate 10 made of metal will be described later.

The insulating portion 20 has insulating properties and is provided on the surface 10 a of the substrate 10 . The insulating part 20 can be provided so as to cover the surface 10a of the substrate 10, for example. The insulating portion 20 is provided to insulate between the substrate 10 made of metal and the heating element 30 and the wiring portion 40 . Therefore, the insulating section 20 is provided between the substrate 10 and the heating element 30 and wiring section 40 . The insulating portion 20 can be made of, for example, an inorganic material such as ceramics or glass material. The insulating portion 20 can be formed by, for example, thermal spraying or firing.

The heating element 30 converts the applied electric power into heat (Joule heat). The heating element 30 is provided on the insulating portion 20 (the surface of the insulating portion 20 opposite to the substrate 10 side). As an example, the case where one heating element 30 is provided is illustrated, but the number and size of the heating elements 30 can be appropriately changed according to the size of the substrate 10 (the size of the object to be heated). (See, eg, FIG. 4). Also, it is possible to provide a plurality of types of heating elements having different lengths, widths, shapes, and the like. That is, at least one heating element 30 should be provided.

The heating element 30 extends, for example, along the longitudinal direction (X direction) of the substrate 10 .
The heating element 30 can be formed using, for example, ruthenium oxide (RuO ₂ ), silver-palladium (Ag—Pd) alloy, or the like. The heating element 30 can be formed by, for example, applying a paste-like material onto the insulating portion 20 using a screen printing method or the like, and curing the material using a baking method or the like.

The wiring part 40 is provided, for example, on the surface of the insulating part 20 on which the heating element 30 is provided. The wiring section 40 has terminals 41 and wirings 42, for example.
The terminal 41 can be provided, for example, near the edge of the substrate 10 in the X direction. The terminal 41 is electrically connected to a power supply, a control circuit, or the like via a connector, wiring, or the like, for example.
The wiring 42 electrically connects the terminal 41 and the heating element 30 . One end of the wiring 42 is electrically connected to the terminal 41 . The other end of the wiring 42 is electrically connected to the heating element 30 .

The terminals 41 and the wirings 42 are formed using a material containing silver, copper, or the like, for example. For example, the terminals 41 and the wirings 42 can be formed by applying a paste-like material onto the insulating portion 20 using a screen printing method or the like and hardening it using a baking method or the like.

The protection part 50 is provided, for example, on the insulating part 20 and extends along the longitudinal direction (X direction) of the substrate 10 . The protection part 50 covers the heating element 30 and the wiring 42, for example. In this case, the terminals 41 are exposed from the protective portion 50 .

The protection unit 50 has, for example, a function of insulating the heating element 30 and the wiring 42, a function of transmitting heat generated in the heating element 30 to the outside, and a function of protecting the heating element 30 and the wiring 42 from external force, corrosive gas, and the like. have The protective portion 50 is made of a material having heat resistance, insulation, chemical stability and thermal conductivity. The protective portion 50 is made of, for example, ceramics or an inorganic material such as a glass material. In this case, the protective portion 50 can also be formed using a glass material to which a filler containing a material with high thermal conductivity such as aluminum oxide is added. The thermal conductivity of the glass material to which the filler is added can be, for example, 2 [W/(m·K)] or more.

Further, the heater 1 may be further provided with a detection section for detecting the temperature of the heating element 30 . The detector can be, for example, a thermistor. The detection unit can be provided on at least one of the side of the substrate 10 on which the heating element 30 is provided and the side of the substrate 10 opposite to the side on which the heating element 30 is provided. The protection part 50 can cover the detection part.

Here, as described above, the insulating portion 20 and the protective portion 50 are made of an inorganic material such as ceramics or glass material. On the other hand, the substrate 10 is made of metal such as stainless steel or aluminum alloy. Further, when the heating element 30 is caused to generate heat when the heater 1 is used, the substrate 10, the insulating portion 20, and the protective portion 50 are heated. When the insulating part 20 and the protective part 50 are baked when the heater 1 is manufactured, the substrate 10, the insulating part 20 and the protective part 50 are heated. Therefore, when the heater 1 is used or manufactured, thermal stress may occur due to the difference in coefficient of thermal expansion of the materials, and the heater 1 may warp. In this case, the difference between the coefficient of thermal expansion of the metal and the coefficient of thermal expansion of the inorganic material is large, so there is a possibility that the heater 1 will warp greatly. When the heater 1 is warped, the distance between the heater 1 and the object to be heated varies, which may cause uneven heating of the object to be heated.

Therefore, the heater 1 is provided with the relief portion 60 .
As shown in FIG. 2, the relief portion 60 is provided on the surface 10b of the substrate 10. As shown in FIG. The relaxing portion 60 is made of, for example, ceramics or an inorganic material such as a glass material. Therefore, the coefficient of thermal expansion of the material of the relief portion 60 is different from the coefficient of thermal expansion of the material of the substrate 10 . As a result, thermal stress is generated due to the difference in coefficient of thermal expansion of the materials when the heater 1 is used or manufactured.

In this case, since the relaxation portion 60 is provided on the side of the substrate 10 opposite to the side on which the protection portion 50 and the like are provided, the thermal stress generated by the substrate 10 and the protection portion 50 and the like is absorbed by the substrate 10 and the relief portion. The thermal stress caused by 60 can be offset. If the thermal stress is offset, it is possible to prevent the heater 1 from warping.

In this case, it is preferable that the magnitude of the thermal stress caused by the substrate 10 and the relief portion 60 be the same as the magnitude of the thermal stress caused by the substrate 10 and the protection portion 50 and the like as much as possible. Therefore, for example, the material and dimensions of the relief portion 60 can be the same as the material and dimensions of the protective portion 50 .

Also, a plurality of relief portions 60 can be provided. When a plurality of relief portions 60 are provided, by changing at least one of the arrangement positions, materials, and volumes (planar dimensions and thickness) of the plurality of relief portions 60, occurrence of warpage can be suppressed or reduced. You can make it smaller. The arrangement positions, materials, and volumes of the plurality of relaxation portions 60 can be appropriately determined by conducting experiments and simulations.

Next, the function and effect of the substrate 10 made of metal will be described.
As described above, the heating element 30 is formed using ruthenium oxide (RuO ₂ ), silver-palladium (Ag—Pd) alloy, or the like. Therefore, the ratio of the manufacturing cost of the heating element 30 to the manufacturing cost of the heater 1 increases. In this case, if the volume of the heating element 30 is reduced, the material cost of the heating element 30 can be reduced. For example, if the width dimension W1 (the dimension in the lateral direction; the dimension in the Y direction) of the heating element 30 is reduced, the volume of the heating element 30 can be reduced, so the manufacturing cost of the heating element 30 can be reduced. The manufacturing cost of the heater 1 can be reduced.

However, in the case of the heater 1 used in the image forming apparatus 100, the width dimension W of the substrate 10 is set within a predetermined range. Therefore, if the width dimension W1 of the heating element 30 is reduced, as shown in FIGS. The distance L between the ends (ends on the long side) increases. As the distance L increases, the area of the portion of the substrate 10 where the heating element 30 is not provided increases. Also, heat escapes more easily in the vicinity of the edges of the substrate 10 than in the central portion of the substrate 10 . Therefore, as the distance L increases, the difference between the temperature near the edge of the substrate 10 and the temperature of the portion of the substrate 10 where the heating element 30 is provided increases.

For example, when the substrate 10 is made of ceramics, if the distance L is 1.5 mm or more, the temperature near the edge of the substrate 10 and the temperature of the portion of the substrate 10 where the heating element 30 is provided will be different. is too large, the substrate 10 may be cracked or chipped.

In this case, if the substrate 10 is made of metal, the thermal conductivity of the substrate 10 can be made higher than that of a substrate made of ceramics. Therefore, the difference between the temperature near the edge of the substrate 10 and the temperature of the portion of the substrate 10 where the heating element 30 is provided can be reduced. In addition, since metal has a higher toughness than ceramics, even if the difference between the temperature near the edge of the substrate 10 and the temperature of the portion of the substrate 10 where the heating element 30 is provided increases, the substrate 10 does not It is possible to suppress the occurrence of cracks, chips, etc.

According to the knowledge obtained by the present inventors, if the substrate 10 is made of metal, even if the distance L is 1.5 mm or more, the substrate 10 can be prevented from being cracked or chipped. . If the distance L can be set to 1.5 mm or more, the width dimension W1 of the heating element 30 can be reduced accordingly. For example, the width dimension W1 of the heating element 30 could be set to 0.3 mm or more and 1.5 mm or less. Therefore, the volume of the heating element 30 can be reduced, so that the manufacturing cost of the heating element 30 can be reduced, and the manufacturing cost of the heater 1 can be reduced.

FIG. 3 is a schematic cross-sectional view of a heater 1a according to another embodiment.
As shown in FIG. 3, the heater 1a has an insulating portion 20, a heating element 30, a wiring portion 40, and a protective portion 50 on the surface 10a side of the substrate 10, like the heater 1 described above. However, in the case of the heater 1 described above, the relaxing portion 60 was provided on the surface 10b of the substrate 10, but in the case of the heater 1a, the insulating portion 20 (second insulating portion) is provided on the surface 10b side of the substrate 10. part), a heating element 30 (corresponding to an example of a second heating element), a wiring part 40, and a protection part 50 (corresponding to an example of a second protection part). That is, the heater 1a is provided with the insulating portion 20, the heating element 30, the wiring portion 40, and the protective portion 50 on both surfaces of the substrate 10, respectively.

Even with the heater 1a having such a configuration, if the substrate 10 is made of metal, even if the distance L is set to 1.5 mm or more, cracking or chipping of the substrate 10 can be suppressed. can. Therefore, the volume of the heating element 30 can be reduced, so that the manufacturing cost of the heating element 30 can be reduced, and the manufacturing cost of the heater 1a can be reduced.

Further, since the insulating portion 20, the heating element 30, the wiring portion 40, and the protective portion 50 are provided on both surfaces of the substrate 10, the thermal stress generated on the surface 10a side of the substrate 10 is It can be canceled by the thermal stress generated on the 10b side. Therefore, it is possible to effectively suppress warping of the heater 1a.

FIG. 4 is a schematic cross-sectional view of a heater 1b according to another embodiment.
As shown in FIG. 4, the heater 1b has a substrate 10, an insulating portion 20, a heating element 30, a wiring portion 40, a protective portion 50, and a relaxing portion 60, like the heater 1 described above. However, in the case of the heater 1 described above, one set of the heating element 30 and the wiring part 40 is provided, but in the heater 1b, a plurality of sets of the heating element 30 and the wiring part 40 are provided. It should be noted that the heater 1b illustrated in FIG. A plurality of sets of heating elements 30 and wiring portions 40 may be connected in series or in parallel.

Even with the heater 1b having such a configuration, if the substrate 10 is made of metal, even if the distance L is set to 1.5 mm or more, cracking or chipping of the substrate 10 can be suppressed. can. Therefore, the volume of the heating element 30 can be reduced, so that the manufacturing cost of the heating element 30 can be reduced, and the manufacturing cost of the heater 1b can be reduced.

If the thermal stress generated on the surface 10a side of the substrate 10 increases due to the provision of the plurality of heating elements 30, the material and dimensions of the relaxation portion 60 may be changed to reduce the heat generated on the surface 10b side of the substrate 10. The stress should be increased.

(Image forming device)
Next, the image forming apparatus 100 according to this embodiment will be illustrated.
In the following, as an example, the case where the image forming apparatus 100 is a copier will be described. However, the image forming apparatus 100 is not limited to a copier, and may be any apparatus provided with a heater for fixing toner. For example, the image forming apparatus 100 can be a printer or the like.

FIG. 5 is a schematic diagram for illustrating the image forming apparatus 100 according to this embodiment.
FIG. 6 is a schematic diagram for illustrating the fixing section 200. As shown in FIG.
As shown in FIG. 5, 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, It has a conveying section 190 , a fixing section 200 and a controller 210 .

The frame 110 has a box-like shape and contains an illumination section 120, an image forming element 130, a photosensitive drum 140, a charging section 150, a developing section 160, a cleaner 170, a part of a storage section 180, a conveying section 190, and a fixing section. 200 and controller 210 .
A window 111 made of a translucent material such as glass can be provided on the top surface of the frame 110 . A document 500 to be copied is placed on the window 111 . Also, a moving unit for moving the position of the document 500 can be provided.

The lighting unit 120 is provided near the window 111 . The lighting 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 section 120 and the imaging element 130 . The photosensitive drum 140 is rotatably provided. The surface of the photosensitive drum 140 is provided with, for example, a zinc oxide photosensitive layer or an organic semiconductor photosensitive layer.
Charging unit 150 , discharging unit 151 , developing unit 160 , and cleaner 170 are provided around photosensitive drum 140 .

The storage section 180 has, for example, a cassette 181 and a tray 182 . Cassette 181 is detachably attached to one side of 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. Cassette 181 stores paper 510 (for example, blank paper) before copying is performed. The tray 182 accommodates the paper 511 on which the copy image 511a is fixed.

The conveying section 190 is provided below the photosensitive drum 140 . The transport section 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 to 194 that transport the paper 510 . Further, the transport section 190 can be provided with a motor for rotating the transport rollers 192 to 194 .

The fixing section 200 is provided downstream of the photosensitive drum 140 (on the tray 182 side).
As shown in FIG. 6, the fixing section 200 has a heater 1, a stay 201, a film belt 202, and a pressure roller 203, for example.
A heater 1 is attached to the stay 201 on the paper 510 transport line side. The heater 1 can be embedded in the stay 201 . In this case, the side of the heater 1 on which the protection portion 50 is provided is exposed from the stay 201 .

A film belt 202 covers a stay 201 on which the heater 1 is provided. The film belt 202 can contain, for example, heat-resistant resin such as polyimide.

The pressure roller 203 is provided so as to face the stay 201 . The pressure roller 203 has, for example, a metal core 203a, a drive shaft 203b, and an elastic portion 203c. The drive shaft 203b protrudes from the end of the metal core 203a and is connected to a drive device such as a motor. The elastic portion 203c is provided on the outer surface of the metal core 203a. The elastic portion 203c is made of a heat-resistant elastic material. The elastic portion 203c can contain silicone resin or the like, for example.

Controller 210 is provided inside 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 calculation 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 can also include an operation unit for inputting copying conditions by the user, a display unit for displaying operation status, error display, and the like.
Note that a known technique can be applied to control each element provided in the image forming apparatus 100, so detailed description thereof will be omitted.

Although some embodiments of the present invention have been illustrated above, these embodiments are presented by way of example 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 scope 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 described in the claims and equivalents thereof. Moreover, each of the above-described embodiments can be implemented in combination with each other.

Reference Signs List 1 heater 1a heater 1b heater 10 substrate 10a surface 10b surface 20 insulating part 30 heating element 40 wiring part 50 protection part 60 relaxation part 100 image forming apparatus 200 fixing part

Claims (4)

a substrate formed of metal and having a shape extending in one direction;
a first insulating portion provided on the first surface of the substrate and having insulating properties;
at least one first heating element provided on the first insulating portion and extending along the longitudinal direction of the substrate;
a first protection portion provided on the first insulation portion, extending along the longitudinal direction of the substrate, and covering the first heating element;
and
A heater in which a distance between a widthwise end of the substrate and a widthwise end of the first heating element is 1.5 mm or more. 2. The heater according to claim 1, further comprising a relief portion provided on a second surface of said substrate opposite to said first surface. a second insulating portion provided on a second surface of the substrate facing the first surface and having insulating properties;
at least one second heating element provided on the second insulating portion and extending along the longitudinal direction of the substrate;
a second protection portion provided on the second surface, extending along the longitudinal direction of the substrate, and covering the second heating element;
further comprising
2. The heater according to claim 1, wherein the distance between the lateral end of said substrate and the lateral end of said second heating element is 1.5 mm or more. An image forming apparatus comprising the heater according to any one of claims 1 to 3.

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