JPH0745358A - Heating body and manufacture of heating body thereof - Google Patents

Abstract

PURPOSE:To provide a higly reliable heating body wherein a part to increase the heating value of a heat radiating resistor can be formed easily with high precision and the part to increase heating value of the heat radiating resistor is not damaged by heating and provide a method to manufacture the heating body. CONSTITUTION:A heating body is provided with a substrate 11 and a heat radiating resistor 13 which is formed on the surface of the substrate and has partly different thickness. The manufacture of the heating body involves forming an insulating body 15 with thinner than the heat radiating resistor 13 on the surface of the substrate 11 by screen printing, then forming the heat radiating resistor on the surface of the substrate by screen printing, and at the same time, covering the insulating body with a part of the heat radiating resistor.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a heating element having a heating resistor formed on the surface of a substrate and a method for manufacturing the heating element.

[0002]

2. Description of the Related Art For example, a heater for heating a thermal paper in a printer head of a dot printer or a heater for heating a recording paper in a fixing device of a copying machine uses a heating body having a heating resistor formed on the surface of a substrate. Has been.

Generally, a heating element used for this type of application has a long glaze layer formed on the surface of a slender base body made of ceramics, and a slender heating resistor formed of a material such as silver-palladium on the surface of the glaze layer. Further, wide terminals are formed on both ends of the heating resistor, and wiring is connected to the terminals. When a current is passed through the heating resistor between the terminals at both ends, the heating resistor generates heat due to electric resistance.

A heating element used for this type of application is required to have a uniform temperature distribution in the length direction of the heating resistor as shown in FIG. However, the intermediate portion of the heating resistor in this heating element receives heat from both ends and is heated to a high temperature. On the other hand, both ends of the heating resistor have heat transfer from the center, but heat transfer from the ends is not substantial, and heat escapes from the wiring formed on the terminals. And the temperature is low.

Therefore, the temperature distribution in the length direction of the heating resistor has a pattern in which the central portion is high and gradually decreases toward both ends. With this temperature distribution,
When the heating element is used as the heater of the printer head of the dot printer, printing on the recording paper portion corresponding to both ends of the heating element may become thin, and when it is used as the heater of the fixing device, The toner fixing on the portions of the recording paper corresponding to both ends of the heating element may become insufficient.

Therefore, conventionally, the width of both ends of the heating resistor is made narrower than the width of the central part, and the cross-sectional area of this part is reduced to increase the electric resistance value thereof, thereby generating heat at both ends. The amount of heat generated is increased to the same degree as the amount of heat generated in the central portion of the heating resistor so that the temperature distribution in the length direction of the heating resistor becomes uniform.

Further, conventionally, when it is necessary to partially raise the temperature of a heating resistor, the above configuration is adopted and the width of that portion of the heating resistor is compared with that of other portions. The temperature is increased by increasing the amount of heat generated by narrowing the temperature.

[0008]

However, in the heating element as described above, there is a structure in which the width of the heating resistor is narrowed in order to obtain a portion having a large amount of heat generation in the heating resistor. , There are the following problems.

That is, in general, a thick film method such as screen printing is used to form a heating resistor on the surface of a substrate. By this screen printing, a narrow portion is accurately formed on the heating resistor. Difficult to do. If the accuracy of forming the portion where the width of the heating resistor is narrow is low, the accuracy of setting the amount of heat generated in that portion is reduced.

Further, in order to partially form a portion having a very high calorific value in the heating resistor, it is necessary to form an extremely thin portion. FIG. 8 shows the structure of the heating element in this case. In the figure, 1 is a substrate, 2 is a glazing layer, 3 is a heating resistor, and 3a is an extremely thin portion of the heating resistor 3. However, such a thin portion 3a is weak in strength and may be burnt by heat generation, resulting in poor reliability.

Since the present invention has been made based on the above circumstances, it is possible to easily and accurately form a portion of the heating resistor that increases the amount of heat generation, and the portion of the heating resistor that increases the amount of heat generation generates heat. Therefore, it is an object of the present invention to provide a heating element which is not burned out and has high reliability, and a manufacturing method thereof.

[0012]

In order to achieve the above object, the heating element of the first invention comprises a base and a heating resistor formed on the surface of the base and having a partially different film thickness. Is characterized by. A heating element according to a second aspect of the present invention includes a base, a heating resistor formed on the surface of the base with a substantially constant thickness, and a heating resistor formed below the heating resistor on the surface of the base. And an insulator which is responsible for part of a predetermined thickness of the resistor.

The heating element of the third invention comprises a substrate, a first heating resistor formed on the surface of the substrate, and a second heating element formed only on the surface of the first heating resistor. And a heating resistor.

A heating element according to a fourth aspect of the present invention includes a substrate, a first heating resistor formed on the surface of the substrate, a portion formed by polymerization on the surface of the first heating resistor, and this portion. A second heat generating resistor having a portion formed on the surface of the base member continuously with the portion.

In order to achieve the above-mentioned object, the method for manufacturing a heating element according to the fifth aspect of the present invention is such that an insulator is formed on the surface of a substrate by a thick film method with a film thickness smaller than that of a heating resistor, The heating resistor is formed on the surface of the substrate by a thick film method, and a part of the heating resistor is formed so as to cover the surface of the insulator.

In the method for manufacturing a heating element according to the sixth aspect of the present invention, the first heating resistor is formed on the surface of the substrate by the thick film method, and then only the surface of the first heating resistor is polymerized by the thick film method. To form a second heating resistor.

In the method for manufacturing a heating element according to the seventh aspect of the present invention, the first heating resistor is formed on the surface of the substrate by the thick film method, and then the second heating resistor is formed on the surface of the first heating resistor by the thick film method. A heating resistor is formed, and a second heating resistor is formed continuously on this portion by superposing on the surface of the substrate.

[0018]

In the heating element of the first aspect of the present invention, a portion having a small film thickness is partially formed on the heating resistor to reduce the cross-sectional area, thereby increasing the electric resistance value and increasing the amount of heat generation. You can For this reason, it is possible to form a portion that increases the amount of heat generation without reducing the width of the heating resistor. Therefore, the portion of the heating resistor that increases the amount of heat generation can be easily and accurately formed by a thick film method such as screen printing. It can be formed, and the portion of the heating resistor that increases the amount of heat generation is not burned by heat generation.

In the heating element according to the second aspect of the present invention, a portion having a small film thickness can be partially formed in the heating resistor by combining the heating resistor and the insulator. The heating element of the third invention is the first
By combining the heat generating resistor and the second heat generating resistor, it is possible to partially form a thin film thickness portion in the heat generating resistor.

In the heating element according to the fourth aspect of the present invention, a portion having a small film thickness can be partially formed in the heating resistor by combining the first heating resistor and the second heating resistor. According to the fifth aspect of the invention, the heating element of the second aspect of the invention can be manufactured easily and accurately by employing a thick film method such as screen printing.

According to the sixth aspect of the invention, the heating element of the second aspect of the invention can be manufactured easily and accurately by employing a thick film method such as screen printing. According to the seventh invention, the heating element of the third invention can be manufactured easily and accurately by employing a thick film method such as screen printing.

[0022]

Embodiments of the present invention will be described with reference to the drawings. Embodiments of the second to fourth inventions embodying the heating element of the first invention will be described. Each example
It is applied to a heater used for a fixing device in a copying machine.

An embodiment of the second invention will be described with reference to FIG. In FIG. 1, 11 is a base made of ceramics such as alumina, which has an elongated shape. A glazing layer 12 is formed on the surface of the base 11. Reference numeral 13 denotes a heating resistor made of a material such as silver-palladium, which has an elongated shape formed on the surface of the glazing layer 12 along the length direction of the substrate 11.

The heating resistor 13 has a width which is substantially constant over the entire length thereof, and terminals 14 having a width wider than that of the heating resistor 13 are continuously formed at both ends thereof. The heating resistor 13 and each terminal 14 have a substantially constant height from the surface of the glazing layer 12, and the central portion 13 of the heating resistor 13
a and each terminal 14 have almost the same film thickness, and the heating resistor 1
The film thickness of both end portions 13b of 3 is set to be smaller than the film thickness of the central portion 13a of the heating resistor 13 by an insulator 15 described later.

The insulator 15 is made of an insulating material and is formed on the surface of the glazing layer 12 at both ends 13b of the heating resistor 13, and the central portion 1 of the heating resistor 13 is formed.
It has a film thickness smaller than that of 3a. The heating resistor 13 is superposed on the surface of the insulator 15. Heating resistor 13
The film thickness of this portion is the thickness obtained by subtracting the film thickness of the insulator 15 from the film thickness of the central portion 13a of the heating resistor 13. Therefore, the film thickness of the insulator 15 and both end portions 13 of the heating resistor 13 are
The sum of the thickness of b and the thickness of b is equal to the thickness of the central portion 13a of the heating resistor 13. That is, the insulator 15 is the heating resistor 13
Bears part of the film thickness.

The manufacturing method of the fifth invention for manufacturing this heating element will be described. First, the glazing layer 12 is formed on the surface of the base 11. Next, as shown in FIG. 3, a film thickness smaller than the film thickness of the central portion 13a of the heating resistor 13 is formed on the surface of the substrate 11 at a position corresponding to both ends 13b of the heating resistor 13 by a thick film method, for example, screen printing. Then, the insulator 15 is formed. Next, the central portion 13a of the heating resistor 13 and the terminal 14 are formed on the surface of the base 11 by screen printing, and both end portions 13b are formed on the surface of the insulator 15 so as to cover the same.

In the heating element having the above-mentioned structure, a thin film portion is formed on both ends 13b of the heating resistor 13 in combination with the insulator 15 to reduce the cross-sectional area, thereby increasing the electric resistance value of the portion. The amount of heat generation can be increased.

Therefore, since it is possible to form a portion for increasing the heat generation amount without reducing the width of the heat generating resistor 13, the portion for increasing the heat generation amount of the heat generating resistor 13 is formed by a thick film method such as screen printing. Therefore, the heating resistor 13 can be formed easily and accurately, and the portion of the heating resistor 13 that increases the amount of heat generation is not burned by heat generation.

The increased heat generation amount at both ends of the heat generating resistor 13 corresponds to the heat generation amount of the central portion 13a of the heat generating resistor 13. Therefore, as shown in FIG. 2, the heating resistor 13 has a uniform amount of heat generation in the entire length direction. Therefore, if this heater is used as a heater for a fixing device in a copying machine,
The toner image on the recording paper can be fixed well.

An embodiment of the third invention will be described with reference to FIG. 5, the same parts as those in FIG. 1 are designated by the same reference numerals. In the figure, reference numeral 19 is a heating resistor, which is composed of a first heating resistor 16 and a second heating resistor 18. Further, 17 is a terminal connected to both ends of the heating resistor 19, which is a first terminal 17a and a second terminal 17b.
It consists of and.

The first heating resistor 16 is formed on the surface of the glazing layer 12 of the substrate 11, and has a length forming the entire length of the heating resistor 19 and a width forming the width of the heating resistor 19. It has a film thickness of a predetermined thickness. A first terminal 17a is integrally and continuously formed at both ends of the heating resistor 19, and this is a film having a width wider than that of the first terminal 17a and the same thickness as that of the first terminal 17a. Have a thickness.

The second heating resistor 18 is formed by superimposing on the surface of the central portion 16a of the first heating resistor 16.
The second heating resistor 18 has a length and width corresponding to the length and width of the central portion 16a of the first heating resistor 16, and has a film thickness of a predetermined thickness.

Further, a second terminal 17b is formed on the surface of the first terminal 17a by superposition, and has a width of the same size as the width of the first terminal 17a and a predetermined thickness. ing. The sum of the film thickness of the first terminal 17a and the film thickness of the second terminal 17 is the film thickness of the terminal 17.

The manufacturing method of the sixth invention for manufacturing the heating element having the above-mentioned structure will be described. As shown in FIG. 4, the first heating resistor 16 and the first terminal 17a are formed on the surface of the glazing layer 12 of the base 11 by screen printing, and then the first heating resistor 16 is screen printed as shown in FIG. The second heating resistor 18 is formed by superposing on the surface of the central portion 16a of the body 16 excluding both end portions 16b.
Is formed on the surface of the terminal 17a to form the second terminal 17b.

In the heating element having the above structure, the heating resistor 1
The film thickness of the central portion of 9 is the same as the film thickness of the first heating resistor 16
While the thickness of the heating resistor 18 is added, the film thickness at both ends is the thickness of only the first heating resistor 16. As a result, the amount of heat generated at both ends of the heating resistor 19 can be increased and a uniform amount of heat generated can be distributed over the entire length.

An embodiment of the fourth invention will be described with reference to FIG. 7, the same parts as those in FIG. 1 are indicated by the same reference numerals. In the figure, reference numeral 23 is a heating resistor, which is composed of a first heating resistor 20 and a second heating resistor 22. Further, 21 is a terminal continuously formed at both ends of the heating resistor 19, which is composed of a first terminal 21a and a second terminal 21b.

The first heating resistor 20 is formed on the surface of the glazing layer 12 of the substrate 11, and has a length that forms the length of the central portion of the heating resistor 23 and the heating resistor 2.
It has a width that forms a width of 3 and a film thickness of a predetermined thickness. The first terminal 21a is provided on the surface of the glazing layer 12 at a position corresponding to the terminal 21, and the first heating resistor 20 is provided.
It is formed separately from the first heating resistor 2
It has a width wider than 0 and the same thickness as the thickness of the first heating resistor 20.

The second heating resistor 22 has a central portion 22a formed by superposing on the surface of the first heating resistor 20, and the glazing layer 12 of the substrate 11 continuous to the central portion 22a.
And both end portions 22b formed on the surface of the. The central portion 22a and both end portions 22b of the second heating resistor 22 are
Is the length forming the length of the heating resistor 23 and the heating resistor 2
3 has a width (the same width of the first heating resistor 20) that forms a width of 3, and further has a film thickness of a predetermined thickness.

On the surface of the first terminal 17a, the second terminal 1 continuous with both ends 22b of the second heating resistor 22 is formed.
7b is formed, and has the same thickness as the width of the first terminal 17a and the same thickness as the second heating resistor 22.

The manufacturing method of the seventh invention for manufacturing the heating element having the above-mentioned structure will be described. As shown in FIG. 6, the first heating resistor 20 and the first terminal 21a are formed on the surface of the glazing layer 12 of the substrate 11 by screen printing. Then, as shown in FIG. A central portion 22a of the second heating resistor 22 that is superposed on the surface of the body 16 and both end portions 22b that are superposed on the surface of the glazing layer 12 are formed, and at the same time, the central portion 22a of the second heating resistor 22 is superposed on the surface of the first terminal 21a. The terminal 22b is formed.

In the heating element having the above structure, the heating resistor 2
The thickness of the central portion of 3 is the same as the thickness of the first heating resistor 20 and the second
While the thickness of the heating resistor 22 is added, the film thickness at both ends is the thickness of only the second heating resistor 22. As a result, the amount of heat generated at both ends of the heating resistor 23 can be increased, and a uniform amount of heat generated can be distributed over the entire length. It should be noted that the present invention is not limited to the above-described embodiments, and can be implemented with various modifications.

[0042]

As described above, according to the heating element of the first aspect of the present invention, the heating resistor has a portion having a thin film thickness and a portion for increasing the amount of heat generation. It is possible to form a portion that increases the amount of heat generation without reducing the width of the body, and a portion that increases the amount of heat generation in the heating resistor can be easily and accurately formed by a thick film method such as screen printing, In addition, the portion of the heating resistor that increases the amount of heat generation is not damaged by heat generation and is highly reliable.

According to the second to fourth aspects of the invention, the heating resistor is formed with a portion for reducing the film thickness to increase the amount of heat generation, and heating with a specific structure excellent in productivity and reliability. You can get the body.

According to the manufacturing method of the fifth invention to the seventh invention, the heating element of the second invention to the fourth invention can be manufactured easily and accurately by employing a thick film method such as screen printing. You can

[Brief description of drawings]

FIG. 1A is a plan view showing a heating body according to an embodiment of the second invention. (B) is the same front view. Figure 1 (c) is
Sectional drawing which follows the AA line of (a).

FIG. 2 is a diagram showing a temperature distribution of a heating body of the same example.

FIG. 3 (a) is a plan view showing manufacturing overheating of the heating body of the embodiment. (B) is the same front view.

FIG. 4A is a plan view showing a manufacturing process of a heating body according to an embodiment of the third invention. (B) is the same front view.

FIG. 5A is a plan view showing a heating body of an embodiment according to the third invention. (B) is the same front view.

FIG. 6A is a plan view showing the manufacturing process of the heating body according to the fourth embodiment of the invention. (B) is the same front view.

FIG. 7A is a plan view showing a heating body according to an embodiment of the fourth invention. (B) is the same front view.

FIG. 8A is a plan view showing an example of a conventional heating element.
FIG. 8B is a sectional view taken along the line BB of FIG.

[Explanation of symbols]

11 ... Base 13 ... Heating resistor, 15 ...
Insulator, 16 ... First heating resistor, 18 ...
Second heating resistor, 19 ... Heating resistor, 20 ... First heating resistor, 22 ... Second heating resistor, 23 ... Heating resistor.

Claims (7)

[Claims] 1. A heating body comprising a base and a heating resistor formed on a surface of the base and having a partially different film thickness. 2. A base, a heating resistor formed on the surface of the base with a substantially constant film thickness, and a predetermined portion of the heating resistor formed on the surface of the base below the heating resistor. And an insulator which is responsible for a part of the film thickness of the heating element. 3. A base, a first heating resistor formed on the surface of the base, and a second heating resistor formed by polymerizing only on the surface of the first heating resistor. A heating element characterized by being. 4. A substrate, a first heating resistor formed on the surface of the substrate, a portion formed by polymerization on the surface of the first heating resistor, and the substrate continuous to this portion. A second heating resistor having a portion formed on the surface of the heating element. 5. A thick film method is used to form an insulator on the surface of the substrate with a thickness smaller than that of the heating resistor, and then the heating resistor is formed on the surface of the substrate by the thick film method. A method for manufacturing a heating element, characterized in that the heating element is formed by covering the surface of the insulator. 6. A thick film method is used to form a first heating resistor on the surface of the substrate, and then a thick film method is used to polymerize only the surface of the first heating resistor to form a second heating resistor. A method for manufacturing a heating element, comprising: 7. A first heating resistor is formed on the surface of the substrate by the thick film method, and then a second heating resistor is formed on the surface of the first heating resistor by the thick film method. A method for producing a heating element, characterized in that the second heating resistor is formed by continuously polymerizing on the surface of the substrate.