JP2020047553A - heater - Google Patents

Abstract

To provide a heater that has both excellent moisture resistance and grease resistance.SOLUTION: A heater includes a substrate, a conductor, a resistance heating element, a first coating layer, and a second coating layer. The conductor is provided on the substrate. The resistance heating element is electrically connected to the conductor and provided on the substrate. The first coating layer is provided on the substrate so as to cover the conductor and the resistance heating element. The second coating layer is provided on the first coating layer and has a higher silicon content than that of the first coating layer.SELECTED DRAWING: Figure 1

Description

  Embodiments of the present invention relate to a heater.

  For example, heaters used for fixing a toner in a copying machine, a facsimile, and the like, and for erasing a print in a rewritable card reader are known. The heater causes a resistance heating element formed on one surface of the substrate to generate heat by electric power supplied from a power supply electrode.

JP 2007-25474 A

  In such a heater, it may be difficult to combine excellent moisture resistance and grease resistance.

  The problem to be solved by the present invention is to provide a heater having both excellent moisture resistance and excellent grease resistance.

  The heater according to the embodiment includes a substrate, a conductor, a resistance heating element, a first coating layer, and a second coating layer. The conductor is provided on the substrate. The resistance heating element is electrically connected to the conductor and provided on the substrate. The first coating layer is provided on the substrate so as to cover the conductor and the resistance heating element. The second coating layer is provided on the first coating layer and has a higher silicon content than the first coating layer.

  According to the present invention, a heater having both excellent moisture resistance and grease resistance can be provided.

It is a top view of a heater concerning an embodiment. It is AA sectional drawing of FIG. It is sectional drawing of the heater which concerns on the modification of embodiment. It is a figure showing a result of an evaluation test. FIG. 3 is a cross-sectional view illustrating a fixing device according to an embodiment using the heater according to the embodiment. 1 is a cross-sectional view illustrating an image forming apparatus according to an embodiment using a heater according to an embodiment.

  The heaters 1 and 1A according to the embodiments described below include a substrate 2, a conductor 3, a resistance heating element 4, a first coating layer 7, and a second coating layer 8. The conductor 3 is provided on the substrate 2. The resistance heating element 4 is electrically connected to the conductor 3 and provided on the substrate 2. The first coating layer 7 is provided on the substrate 2 so as to cover the conductor 3 and the resistance heating element 4. The second coating layers 8 and 8A are provided on the first coating layer 7, and have a higher silicon content than the first coating layer 7.

  Further, the second coating layers 8 and 8A according to the embodiment described below have a higher zinc content than the first coating layer 7.

  Further, the second coating layers 8 and 8A according to the embodiment described below have a lower alkaline earth metal content than the first coating layer 7.

  Further, the second coating layers 8 and 8A according to the embodiment described below have a larger (content of silicon and zinc) / (content of alkaline earth metal) than the first coating layer 7.

[Embodiment]
A heater according to an embodiment will be described with reference to the drawings. FIG. 1 is a plan view of the heater according to the embodiment. FIG. 2 is a sectional view taken along line AA of FIG. The heater 1 according to the embodiment is mounted on electronic devices and mainly heats a medium such as paper that passes therethrough. As shown in FIG. 1, the heater 1 includes a substrate 2, a conductor 3, a resistance heating element 4, power supply electrodes 5 and 6, a first coating layer 7, and a second coating layer 8. Have been.

  The substrate 2 has heat resistance and insulating properties, and is formed in a rectangular shape in the present embodiment. The substrate 2 is a flat plate made of, for example, ceramic such as alumina or aluminum nitride, glass ceramic, or a heat-resistant composite material. The substrate 2 has a thickness corresponding to a space in which the heater 1 can be mounted, and is, for example, about 0.5 mm to 1.0 mm. The shape of the substrate 2 is not limited as long as it has a short direction (Y direction) and a long direction (X direction) intersecting the short direction. , Chips or the like may be formed. Note that the longitudinal direction of the substrate 2 may be referred to as an “X direction” and the lateral direction may be referred to as a “Y direction”.

  The conductor 3 supplies power to the resistance heating element 4 and is provided on the substrate 2. The conductor 3 is a conductor pattern formed on the substrate 2 with a conductor paste such as silver (Ag). The conductor 3 in the present embodiment is electrically connected to the resistance heating element 4 in the X direction, which is the longitudinal direction of the heater 1 (substrate 2). The conductors 31 and 32 included in the conductor 3 and the conductor 33 are provided apart from each other in the X direction, and the resistance heating elements 41 and 42 are disposed therebetween. The conductor 31 is formed along the longitudinal direction of the resistance heating element 41, and one end is electrically connected to the power supply electrode 5 and the other end is electrically connected to one end of the resistance heating element 41. ing. The conductor 32 is formed along the longitudinal direction of the resistance heating element 42, and one end is electrically connected to the power supply electrode 6 and the other end is electrically connected to one end of the resistance heating element 42. ing. The conductor 33 is electrically connected to the other ends of the resistance heating elements 41 and 42, respectively. That is, the conductor 3 is electrically connected along the longitudinal direction of the resistance heating element 4.

  The resistance heating element 4 is electrically connected to the conductor 3 and is provided on the substrate 2. The resistance heating element 4 generates heat by passing electricity. The resistance heating element 4 is a heating element pattern formed of a heating element paste of, for example, a silver-palladium-based, graphite-based, ruthenium oxide-based, or the like. In the present embodiment, the resistance heating elements 4 are arranged along the X direction. The resistance heating element 41 and the resistance heating element 42 included in the resistance heating element 4 are spaced apart in the Y direction. The resistance heating elements 41 and 42 are arranged in strips along the X direction so that the length of the heater 1 in the short direction is constant.

  The pair of power supply electrodes 5 and 6 are electrically connected to the conductor 3, respectively, and are provided on the substrate 2. The pair of power supply electrodes 5 and 6 are provided at the end of the substrate 2 in the X direction as shown in FIG. The pair of power supply electrodes 5 and 6 are electrically connected to the conductors 31 and 32, respectively, and are electrically connected to the conductors 31 and 32. Although the pair of power supply electrodes 5 and 6 are provided at one end of the substrate 2 in FIG. 1, they may be provided at both ends or at the other end. You may. The pair of power supply electrodes 5 and 6 are usually formed on the substrate 2 integrally with the conductors 31 and 32, respectively, but the pair of power supply electrodes 5 and 6 and the conductors 31 and 32 are respectively formed. It may be formed separately. The pair of power supply electrodes 5 and 6 are disposed on the surface of the substrate 2 on which the conductors 31 and 32 are provided, but are disposed on the surface opposite to the surface on which the conductors 31 and 32 are provided. It may be. In this case, the pair of power supply electrodes 5 and 6 are electrically connected to the conductors 31 and 32 via through holes formed in the substrate 2.

  The first coating layer 7 is a protective layer and covers the conductor 3 and the resistance heating element 4 provided on the substrate 2, and is formed in a belt shape in the present embodiment. The first coating layer 7 covers the conductor 3 and the resistance heating element 4, thereby preventing the conductor 3 and the resistance heating element 4 from being directly exposed to the atmosphere, and preventing external interference (for example, mechanical and chemical interference). This prevents the conductor 3 and the resistance heating element 4 from being damaged or broken due to electrical interference.

  The second coating layer 8 is provided on the first coating layer 7. In the present embodiment, the dimensions in the X direction and the Y direction are arranged so as to be the same as those of the first coating layer 7. However, the present invention is not limited to this. May also be small.

  Further, the total thickness of the first coating layer 7 and the second coating layer 8, that is, the height from the surface of the substrate 2 to the upper surface of the second coating layer 8 can be, for example, 30 μm or more and 80 μm or less. From the viewpoint of providing thermal conductivity, the thickness can be particularly set to 30 μm or more and 50 μm.

  Each of the first coating layer 7 and the second coating layer 8 is a glass layer having a thermal conductivity higher than that of the substrate 2 and, for example, 2 [W / (m · K)] or more. As described above, the first coating layer 7 and the second coating layer 8 have compositions similar to each other, but have excellent moisture resistance by changing the content of some components as described below. And grease resistance.

  In the heater 1 according to the embodiment, the silicon content differs between the first coating layer 7 and the second coating layer 8. Specifically, the second coating layer 8 has a higher silicon content than the first coating layer 7. Here, the silicon content greatly contributes to moisture resistance and grease resistance. When the silicon content is increased, the grease resistance is reduced and the moisture resistance is increased. When the silicon content is reduced, the moisture resistance is decreased and the grease resistance is increased. For this reason, by defining the content of silicon in the first coating layer 7 and the second coating layer 8, the first coating layer 7 mainly contributes to grease resistance, and the second coating layer 8 mainly includes moisture resistance. Can be contributed to.

  Further, in the heater 1 according to the embodiment, the zinc content differs between the first coating layer 7 and the second coating layer 8. Specifically, the second coating layer 8 has a higher zinc content than the first coating layer 7. Here, the zinc content greatly contributes to moisture resistance. That is, the higher the zinc content, the higher the moisture resistance. Therefore, by setting the zinc content of the second coating layer 8 higher than that of the first coating layer 7, the moisture resistance of the second coating layer 8 can be increased.

  In the heater 1 according to the embodiment, the content of the alkaline earth metal is different between the first coating layer 7 and the second coating layer 8. Specifically, the second coating layer 8 has a lower alkaline earth metal content than the first coating layer 7. Here, the content of the alkaline earth metal greatly contributes to the moisture resistance. That is, when the content of the alkaline earth metal is reduced, the moisture resistance is increased. For this reason, the moisture resistance of the second coating layer 8 can be increased by setting the content of the alkaline earth metal of the second coating layer 8 lower than that of the first coating layer 7.

  Examples of the alkaline earth metal contained in the first coating layer 7 and the second coating layer 8 include beryllium, magnesium, calcium, strontium, and barium. The first coating layer 7 and the second coating layer 8 can contain one or more of the above-mentioned alkaline earth metals.

  In the heater 1 according to the embodiment, the value of (content of silicon and zinc) / (content of alkaline earth metal) is different between the first coating layer 7 and the second coating layer 8. Specifically, the second coating layer 8 has a higher (content of silicon and zinc) / (content of alkaline earth metal) than the first coating layer 7. As described above, the higher the content of silicon and zinc, the higher the moisture resistance. Further, when the content of the alkaline earth metal is reduced, the moisture resistance is increased. Therefore, by setting the value of (content of silicon and zinc) / (content of alkaline earth metal) of the second coating layer 8 larger than that of the first coating layer 7, the moisture resistance of the second coating layer 8 can be improved. Can be enhanced.

[Modification]
FIG. 3 is a cross-sectional view of a heater according to a modification of the embodiment. The heater 1A shown in FIG. 3 differs from the heater 1 in that the dimension of the second coating layer 8A in the Y direction is larger than that of the first coating layer 7. Further, both ends in the Y direction of the second coating layer 8 </ b> A protrude from both ends in the Y direction of the first coating layer 7, and are arranged so as to contact the surface 2 a of the substrate 2. Thereby, both ends in the Y direction of the first coating layer 7 are completely covered with the second coating layer 8A. According to the heater 1A in which the second coating layer 8A is arranged, the moisture resistance can be further improved. In the illustrated heater 1A, both ends of the second coating layer 8A in the Y direction are disposed so as to protrude from both ends of the first coating layer 7 in the Y direction. However, the present invention is not limited to this. Both ends in the direction may be arranged so as to protrude from both ends in the X direction of the first coating layer 7. Further, a part of the second coating layer 8 </ b> A may protrude from the end of the first coating layer 7 in the X direction or the Y direction, and may be arranged so as to be in contact with the surface 2 a of the substrate 2.

[Evaluation test]
An acceleration test was performed using a prototype of the heater, and the moisture resistance and the grease resistance due to the difference in the composition of the first coating layer 7 and the second coating layer 8 were evaluated. FIG. 4 shows the results. In addition, the analysis method of the amount of silicon, the amount of zinc, and the amount of alkaline earth metal is as follows. The component contents of the first coating layer 7 and the second coating layer 8 were measured using JEOL. In FIG. 4, A is the value of (content of silicon and zinc) / (content of alkaline earth metal) in the second coating layer 8, and B is the value of (content of silicon and zinc) in the first coating layer 7. (Content) / (content of alkaline earth metal). In FIG. 4, the amounts of the elements are defined by a silicon ratio, a zinc ratio, and an alkaline earth metal ratio, respectively. The silicon ratio, the zinc ratio, and the alkaline earth metal ratio are values normalized to be 100% when the three types of ratios are added, and the ratio of (silicon and zinc) / alkali in the second coating layer 8 The value of (earth metal ratio) is substantially the same as the value of (silicon and zinc content) / (alkali earth metal content) in the second coating layer 8. Similarly, the value of (ratio of silicon and zinc) / ratio of alkaline earth metal in first coating layer 7 is substantially equal to (content of silicon and zinc) / (alkaline earth element) in first coating layer 7. This is synonymous with the value of (metal content).

  In addition, the moisture resistance was evaluated by placing the sample that passed the withstand voltage test in a constant temperature room at room temperature of 85 ° C. and a relative humidity of 95% for 2000 hours, and performing the withstand voltage test again. In the withstand voltage test, current was applied at an applied voltage of AC 1500 V for 3 seconds, and a sample having a cutoff current of 1 mA or less was evaluated as ○, and a sample having a cutoff current exceeding 1 mA was evaluated as ×. The grease resistance is as follows. A sample in which an appropriate amount of grease is applied to the surface of the second coating layer 8 is left in a thermostatic chamber at 380 ° C. for 1.5 hours. Evaluation was made by observing the appearance. Then, as a result of the external appearance observation, も の indicates that no erosion of the first coating layer 7 or the second coating layer 8 was confirmed, and X indicates that erosion was confirmed. From these results, conditions that combine moisture resistance and grease resistance were confirmed.

  As described above, the heaters 1 and 1A according to the embodiment include the substrate 2, the conductor 3, the resistance heating element 4, the first coating layer 7, and the second coating layers 8 and 8A. The conductor 3 is provided on the substrate 2. The resistance heating element 4 is electrically connected to the conductor 3 and provided on the substrate 2. The first coating layer 7 is provided on the substrate 2 so as to cover the conductor 3 and the resistance heating element 4. The second coating layers 8 and 8A are provided on the first coating layer 7, and have a higher silicon content than the first coating layer 7. Thus, a heater having both excellent moisture resistance and excellent grease resistance can be provided.

  Further, the second coating layers 8 and 8A according to the embodiment have a higher zinc content than the first coating layer 7. Thus, a heater having both excellent moisture resistance and excellent grease resistance can be provided.

  Further, the second coating layers 8 and 8A according to the embodiment described below have a lower alkaline earth metal content than the first coating layer 7. Thus, a heater having both excellent moisture resistance and excellent grease resistance can be provided.

  Further, the second coating layers 8 and 8A according to the embodiment described below have a larger (content of silicon and zinc) / (content of alkaline earth metal) than the first coating layer 7. Thus, a heater having both excellent moisture resistance and excellent grease resistance can be provided.

[Configuration of fixing device]
Next, a fixing device of an embodiment using the heater 1 of the embodiment will be described as an example with reference to the drawings. FIG. 5 is a cross-sectional view illustrating a fixing device according to an embodiment using the heater according to the embodiment. As shown in FIG. 5, in the fixing device 200, a heater 1 is provided at the bottom of a fixing film belt 201 that is wound around a support 202 in a cylindrical shape. The fixing film belt 201 is formed of a heat-resistant resin material such as polyimide. A pressure roller 203 is arranged at a position facing the heater 1 and the fixing film belt 201. The pressure roller 203 has a heat-resistant elastic material, for example, a silicone resin layer 204 on its surface, and rotates around the rotation shaft 205 (P direction in FIG. 5) in a state where the fixing film belt 201 is pressed. be able to.

  In the toner fixing step, on the contact surface between the fixing film belt 201 and the silicone resin layer 204, the toner image U1 attached to the recording paper (copying paper) M as a medium is heated by the heater 1 via the fixing film belt 201. Is melted. As a result, at least the surface portion of the toner image U1 exceeds the melting point and is softened and melted. Thereafter, on the paper discharge side of the pressure roller 203, the recording paper M separates from the heater 1 and also separates from the fixing film belt 201, and the toner image U2 naturally radiates heat and solidifies again, so that the toner image U2 Is fixed on the recording paper M.

[Configuration of Image Forming Apparatus]
Finally, an image forming apparatus according to an embodiment including the heater 1 according to the embodiment will be described with reference to the drawings. FIG. 6 is a cross-sectional view illustrating an image forming apparatus according to the embodiment using the heater according to the embodiment. The image forming apparatus according to the present embodiment is configured as a copying machine 100. As shown in FIG. 6, in the copying machine 100, components including the above-described fixing device 200 are provided in a housing 101. An original mounting table made of a transparent material such as glass is attached to the upper part of the housing 101, and the original M1 from which image information is to be read is reciprocated on the original mounting table (the Q direction in FIG. 6). ) The document M1 is configured to be scanned.

  An illumination device 102 having a light irradiation lamp and a reflecting mirror is provided at an upper portion in the housing 101. The light emitted from the illuminating device 102 is reflected on the surface of the original M1 on the original placing table, and is slit-exposed on the photosensitive drum 104 by the short-focus small-diameter imaging element array 103. The photosensitive drum 104 is provided rotatably (R direction in FIG. 6). In addition, a charger 105 is provided near the photosensitive drum 104 disposed in the housing 101, and the photosensitive drum 104 is uniformly charged by the charger 105. The photosensitive drum 104 is covered with, for example, a zinc oxide photosensitive layer or an organic semiconductor photosensitive layer. On the charged photosensitive drum 104, an electrostatic image subjected to image exposure by the short focus small diameter imaging element array 103 is formed. This electrostatic image is visualized using a toner made of a resin or the like that softens and melts when heated by the developing device 106, and becomes a toner image.

  The recording paper M stored in the cassette 107 is placed on the photosensitive drum 104 by a pair of conveying rollers 109 which are rotated while being vertically pressed and rotated in synchronization with the feed roller 108 and the toner image on the photosensitive drum 104. Sent in. Then, the toner image on the photosensitive drum 104 is transferred onto the recording paper M by the transfer discharger 110. After that, the recording paper M sent from the photosensitive drum 104 to the downstream side is guided to the fixing device 200 by the conveyance guide 111, subjected to the heat fixing process (the above-described toner fixing process), and then discharged to the tray 112. After the transfer of the toner image, the residual toner on the photosensitive drum 104 is removed by the cleaner 113.

  In the fixing device 200, the heater 1 is provided in a state where the heater 1 is pressed against the silicone resin layer 204 attached to the outer periphery of the pressure roller 203. The heater 1 has an effective length in the width direction of the recording paper M orthogonal to the conveying direction of the recording paper M, which is in accordance with the width (length) of the maximum size paper that can be copied by the copier 100, that is, the width of the maximum size paper ( (Length). Then, the unfixed toner image on the recording paper M sent between the heater 1 and the pressure roller 203 is melted by utilizing the heat generated by the resistance heating elements 41 and 42, and characters, symbols, A copy image such as an image appears.

  Although an example has been described in which the heater 1 of the embodiment is applied as a fixing heater of an image forming apparatus such as the copying machine 100, the use of the heater 1 is not limited. The heater 1 of the embodiment may be used as a heat source for heating or keeping heat by mounting it on household electric appliances, precision machinery for business use or experiment, equipment for chemical reaction, or the like.

  Although embodiments of the present invention have been described, the embodiments are presented by way of example and are not intended to limit the scope of the invention. The embodiment can be implemented in other various forms, and various omissions, replacements, and changes can be made without departing from the spirit of the invention. The embodiments and their modifications are included in the scope and gist of the invention, and are also included in the invention described in the claims and the equivalents thereof.

DESCRIPTION OF SYMBOLS 1, 1A Heater 2 Substrate 3 Conductor 4 Resistance heating element 5, 6 Power supply electrode 7 First coating layer 8, 8A Second coating layer

Claims (4)

A substrate;
A conductor provided on the substrate;
A resistance heating element electrically connected to the conductor and provided on the substrate;
A first coating layer provided on the substrate to cover the conductor and the resistance heating element;
A second coating layer provided on the first coating layer and having a higher silicon content than the first coating layer;
A heater comprising:   The heater according to claim 1, wherein the second coating layer has a higher zinc content than the first coating layer.   3. The heater according to claim 1, wherein the second coating layer has a lower alkaline earth metal content than the first coating layer. 4.   The heater according to any one of claims 1 to 3, wherein the second coating layer has a larger content of (silicon and zinc) / (content of alkaline earth metal) than the first coating layer.

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