JPH02186585A - Heating body - Google Patents

Abstract

PURPOSE:To make an effective length long compared to the length of a base body by specifying an angle of an edge line of a boundary part between a heat generating part and a terminal part of an electric heating body so as to generate heat strongly at the boundary part and compensate heat loss to the terminal part for making portions even close to the boundary part at a proper temperature. CONSTITUTION:An edge line of a boundary part 33 between a heat generating part 31 and a terminal part 32 of an electric heating body 3 is set at an angle of less than 90 deg., so that heat generating part 31 is maintained thin till it is connected with the terminal parts 32, 33. If current is applied between both terminal parts 32, 32, the heat generating part 31 generates heat, and the heat is transmitted to a protective film 4 to make a high temperature, where heat generation is more at both end parts 23 than at a center part, and this compensates heat loss in the direction of the terminal part 32 to equalize local temperature. The width of the heat generating part 31 is especially small at the boundary part 33, while its resistance is the highest and heat generation quantity is the largest there, so heat loss by heat transmission to the terminal part 32 is compensated, and the temperatures is increased to be proper even at portions close to the boundary part 33. A large effective length can thus be obtained compared to the length of a base body.

Description

Detailed Description of the Invention [Objective of the Invention] (Industrial Application Field) The present invention provides a heating element in which an electric heating element is provided on a base, and the effective heating range (effective heating range) of the electric heating element relative to the length of the base. long)
This is a long version of , and is especially suitable for low-output applications.

(Prior Art) In recent years, contact-type heating bodies have been used in office equipment (OA equipment). For example, in a facsimile machine, a pattern is formed by continuous dots on thermal paper that advances while in contact with a long heating element, or in a copying machine, copy paper on which a toner image forming a pattern has been transferred is brought into contact with a long heating element. It has many uses, including fixation.

Such a heating body is made of a long and thin plate-shaped base made of alumina ceramics or the like, and a metal such as silver/palladium alloy powder is coated on the surface of the base, and wide terminal portions are provided at both ends of the long and thin heat-generating portion in an approximately T-shape or L-shape. An electric heating element is provided, and the surface of the heating part is covered with a glassy protective film.

(Problem to be Solved by the Invention) In order to facilitate the work of printing wiring the electric heating element in the conventional heating element, the boundary between the heating part and the terminal part is curved into an edge line. or tapered. As a result, paste preparation and printing work have become easier, but on the other hand, the resistance value is lower due to the wider boundary area, which generates less heat.Furthermore, the heat at the boundary area is transferred to the terminal area, so the boundary area and It was inevitable that the temperature at the end of the heat generating section adjacent to this would be 11.1 degrees lower. Therefore, only the central part of the heat generating part reaches an effective temperature, and the parts adjacent to the boundary have a low temperature.
Couldn't use it. This can be solved by making the heating element itself longer and using only the central part, but in this case, O
Another drawback is that the A device is large.

Therefore, an object of the present invention is to provide a heating element having a long effective length relative to the length of the base body.

[Structure of the invention]

(Means for Solving the Problems) The present invention is for providing a heating element having a long effective length in proportion to the length of the base body, and the edge line of the boundary between the heat generating part and the terminal part of the electric heating element is 90. The angle is less than 1°.

(Function) By making the edge line of the boundary part at an angle of 90° or less, the heating part can be maintained in a thin state until it connects to the terminal part, and it can be configured to have high resistance up to the boundary with the terminal part, so that it is sufficiently By generating heat and compensating for heat loss to the terminal part, the effective temperature can be reached up to the immediate vicinity of the boundary, and the effective length can be increased.

(Example) The details of the invention will be explained by means of illustrated embodiments.

(1) is an elongated plate-like substrate made of 96% alumina ceramics, (2) is a craze layer (2) with an evenly distributed IC formed on the entire two sides of this substrate (1), and (3) is a craze layer (2).
The electric heating element (4) formed on the surface is a glassy protective film that covers the craze layer (2) including the surface of the electric heating element (3).

The electric heating element (3) is made by screen printing and baking silver/palladium alloy powder on the surface of the brace layer (2), and has wide terminal parts (32) at both ends of the elongated heating part (31). ), and the exposed surface of the craze layer (2) including the surface of the heat generating part (1) is covered with a protective film (4), and a part of the protective film (4) is in contact with the terminal part (32). Boundary part (33
) is coated. Then, a silver film (34) is baked onto the exposed portion of the terminal portion (32).

As shown in FIG. 3, the characteristic of the heating element of this embodiment is that the width of the heat generating part (31) gradually becomes narrower as it approaches the terminal part (32), and the edge line of the boundary part (33) The angle 0, that is, the angle at which the side edge of the heat generating portion (3) intersects the edge line of the terminal portion (32) forms an acute angle.

Therefore, at the end of the heat generating part (31), the boundary (
33) is formed to be the narrowest and has the highest resistance.

Incidentally, the dimensions of each part of the main heating body are shown below.

Length of base (1): 300mm
Width of 1)] Thickness of Onwn substrate (1) 1.5 to 2+nm Grace M (
2) Thickness: 100μ Length of heat generating part (31): 280 mm Center width of heat generating part (31) 2.5 mm End width of heat generating part (31)
], , 5 mm Width of the boundary of the heat generating part (31) 1.0 of the closed terminal part (32) @10 m Thickness of each part of the heat generating element (3) 10 μm Explain the effect of Both terminals (32
) and (32), the heat generating portion (31) generates heat, and the heat is transferred to the protective film (4), resulting in a high temperature.

Therefore, the width of the heat generating part (31) at the center is 2.5 mm and the width at both ends is larger than 5 mm, so more heat is generated at both ends than at the center, and this heat is generated in the direction of the terminal part (32). The loss is compensated for and the local temperature becomes uniform.

In particular, the width of the heat-generating part (31) at the boundary part (33) is very small, so it has the highest resistance and has the largest number of heat-generating parts. As a result, the temperature rises to an appropriate temperature up to the area closest to the boundary (33), and therefore, compared to the conventional wide boundary area, even though the length of the heat generating part is the same, the appropriate temperature range is much longer. A larger effective length can be obtained in terms of body length.

In the above-described embodiment, the angle of the edge line of the boundary portion is an acute angle, but in the present invention, the same effect can be obtained even if the edge line is at a right angle. However, if the angle of the edge line at this boundary is small, the temperature gradient at the boundary will increase and the wire will break easily, so it is recommended to apply it to a low-output heating element or to easily replace the heating element when the wire breaks. It is desirable to take measures such as Further, in the present invention, the brace layer is not necessarily required, and for example, the base body itself may be made of a material with high heat insulation properties. Also. The terminal part may be enlarged only on one side of the heat generating part; the important thing is that the resistance value is low, the area is large enough to easily connect the electric wire, and the angle of the edge line at the boundary part is 90°.
The following is sufficient.

〔Effect of the invention〕

As described above, in the heating element of the present invention, since the angle of the latitude line at the boundary between the heating part of the electric heating element and the terminal part is 90 degrees or less,
The entire heat-generating group, especially the boundary area, generates a strong amount of heat, compensating for the heat loss to the terminal area, and heating the area closest to the boundary area to an appropriate temperature, so it has the advantage of having a long effective length relative to the length of the base body.

[Brief explanation of the drawing]

FIG. 1 is a plan view of an embodiment of the heating body of the present invention, FIG. 2 is a sectional view thereof, and FIG. 3 is an enlarged plan view of the main parts. (1)...Base (2)...Brace layer (3)...Electric heating element (31)
... Heat generating part (32) ... Terminal part (3
3)...Boundary part (34)...Silver film
(4)...Protective film (θ)...Angle of edge line of boundary area Agent Norio Ogo, patent attorney

Claims (1)

[Claims] In a heating element provided with an electric heating element formed by forming a wide terminal part at the end of an elongated heating part on a base, the border between the heating part and the terminal part has an edge line at an angle of 90 degrees or less. A heating element characterized by: