【発明の詳細な説明】
〔発明の目的〕
（産業上の利用分野）
本発明は基体上に電気発熱体を設けた加熱体において、
基体長の割りに電気発熱体の有効加熱範囲（有効長）を
長くしたもので，特に低出力のものに適する．
（従来の技術）
近年、事務用機器（ＯＡ機器）において接触形の加熱体
が用いられている．たとえばファクシミリにおいて，長
形加熱体に接触しながら進行する纏熱紙に連続打点して
パターンを形成し，あるいは複写機において，パターン
をなすトナー像を転写した複写紙を長形加熱体に接触さ
せて定着するなど多くの用途がある．
このような加熱体はアルミナセラミクスなどからなる細
長い板状基体表面に金属たとえば銀・パラジウム合金粉
末をプリントしてなり、細長い発熱部の両端に幅広の端
子部をほぼ丁字形またはＬ字形に形成してなる電気発熱
体を設け，かつ発熱部表面をガラス質の保護膜で被覆し
てある．（発明が解決しようとする課題）
このような従来の加熱体は電気発熱体をプリント配線す
るときのプリント作業を容易にするため、発熱部と端子
部との境界部は縁線にカーブを付したり，テーパを付し
たりしていた．この結果、ぺ一ストの調合やプリント作
業は容易になったが，その反面，境界部が幅広くなるた
め抵抗値が小さくて発熱が少なく，シかも境界部の熱が
端子部にうばわれるため，境界部およびこれに隣接した
発熱部の端部の温度が低くなることは避けられなかった
．このため、．発熱部中有効な温度に達するのは中央部
だけで境界部に隣接した部位は温度が低くて，使用でき
なかった．この対策として加熱体自体を長大にして中央
部だけ使用すれば解決できるが，この場合はＯＡ機器が
大形になる別な欠点が出じる．
そこで，本発明の課題は基体長の割りに有効長の長い加
熱体を提供することである．
〔発明の構成〕
（課題を解決するための手段）
本発明は基体長の割りに有効長の長い加熱体を提供する
ためのもので，電気発熱体の発熱部と端子部との境界部
の緯線を９０゜以下の角度にしたものである．
（作 用）
境界部の縁線を９０゜以下の角度にすれば発熱部を端子
部に連接するまで細い状態に維持することができ，端子
部との境界まで高抵抗に構成して充分に発熱させ、端子
部への熱損失を補って，境界の直近まで有効な温度に達
し、有効長を長くすることができる．
（実施例）
本発明の詳細を図示の実施例によって説明する．（１）
は９６％アルミナセラミクスからなる細長い板状基体、
（２）はこの基板（１）の上面の全面に均一積層された
グレース層，（３）はグレース層（２）表面に形成され
た電気発熱体、（４）はこの電気発熱体（３）の表面を
含めてグレース層（２）を被覆したガラス質保護膜であ
る．
上記電気発熱体（３）は，銀・パラジウム合金粉末をグ
レース層（２）表面にスクリーン印刷して焼付けてなる
もので、細長い発熱部（３ｌ）の両端部に幅広の端子部
（３２）を形成し、発熱部（１）表面を含めてグレース
層（２）露出面を保護膜（４）で被覆してあり，かつ保
護膜（４）の一部が端子部（３２）との境界部（３３）
まで被覆してある．そうして，端子部（３２）の露出面
には銀膜（３４）を焼付けてある．そうして，本実施例
加熱体の特徴は第３図に示すように，発熱部（３１）の
幅が端子部（３２）に近ずくに従って順次細くなり、境
界部（３３）の縁線の角度θすなわち発熱部（３ｌ）の
側縁が端子部（３２）の縁線と交差する角度が鋭角をな
していることである．したがって，発熱部（３１）の端
部においては境界部（３３）が最も輻狭く形成され、最
も高抵抗になっている．
ちなみに、本加熱体の各部寸法を次に示す．基体（１）
の長さ ３００ｍ基体（１）の幅
１０■基体（１）の厚さ
１．５〜２ｍグレース層（２）の厚さ
１００μ発熱部（３ｌ）の長さ ２８
０ｍ発熱部（３１）の中央部＠２ ． ５ ｍ発熱部（
３ｌ）の端部＠ １．５■発熱部（３１）
の境界部の幅 １．０−端子部（３２）の帽
１０ｍ発熱体（３）各部の厚さ ほ
ぼ一様に１０μつぎに，本実施例加熱体の作用を説明す
る．ＷＪ端子部（３２） ． （３２）間に通電すれば
，発熱部（３ｌ）が発熱し、その熱が保護膜（４）に伝
達され高温になる．しかして，発熱部（３ｌ）は中央部
の幅が２．５閣で両端部の幅１．５ｍより大きいので，
中央部よリ両端部においてより多く発熱し，これが端子
部（３２）方向の熱損失を補って局部温度が均一になる
．特に、境界部（３３）において発熱部（３ｌ）の幅は
わずかに１．０ｍＬかないので最も高抵抗で、最も発熱
量が多く，シたがって端子部（３２）への伝熱による熱
損失を補って、境界部（３３）の直近部位まで適温に上
昇し，したがって，従来の境界部を広幅にしたものに比
較して発熱部の長さが同じでも適温範囲がはるかに長く
なり，同じ基体長でもより大きな有効長が得られる．
なお、上述の実施例においては境界部の縁線の角度を鋭
角にしたが．本発明においては直角でも同様な効果があ
る．ただし，この境界部の縁線の角度が小さいと，境界
部における温度勾配が大きくなって断線しやすくなるの
で、低出力の加熱体に適用するかあるいは断線したとき
の加熱体の交換を容易にするなどの工夫が菫ましい．ま
た，本発明において、グレース層は必ずしも必要でなく
，たとえば基体そのものを断熱性の大きい物質で構成し
てもよい，また，端子部は発熱部の片側だけで拡大して
も一良く，要は抵抗値が低く，かつ電線を容易に接続で
きるだけの面積があり、かつ境界部の縁線の角度が９０
°以下であればよい．〔発明の効果〕
このように、本発明の加熱体は電気発熱体の発熱部と端
子部との境界部の縁線の角度を９０＠以下にしたので、
発熱部全体、特に境界部において強力に発熱し，端子部
への熱損失を補って境界部に直近する部位まで適温に熱
せられるので基体長の割りに有効長が長い利点がある．[Detailed Description of the Invention] [Object of the Invention] (Industrial Application Field) The present invention provides a heating element having an electric heating element provided on a base,
The effective heating range (effective length) of the electric heating element is long compared to the length of the base, and is particularly suitable for low output. (Prior Art) In recent years, contact type heating elements have been used in office equipment (OA equipment). For example, in a facsimile machine, a pattern is formed by continuous dots on a sheet of thermal paper that advances while in contact with a long heating element, or in a copying machine, a copy paper onto which a toner image forming a pattern has been transferred is brought into contact with a long heating element. It has many uses, such as being established in the soil. Such a heating element is made by printing a metal such as a silver/palladium alloy powder on the surface of a long and thin plate-like base made of alumina ceramics, etc., and has wide terminals formed in an approximately T-shape or L-shape at both ends of the long and thin heat generating part. An electric heating element is provided, and the surface of the heating element is covered with a glassy protective film. (Problem to be Solved by the Invention) In order to facilitate printing work when printing wiring the electric heating element, such a conventional heating element has a curved edge line at the boundary between the heating part and the terminal part. It was also tapered. As a result, it has become easier to mix paste and print, but on the other hand, because the border area is wider, the resistance value is lower and less heat is generated. It was inevitable that the temperature at the boundary and the adjacent end of the heat-generating section would be low. For this reason,. Among the heat generating parts, only the central part reached an effective temperature, and the parts adjacent to the boundaries were too cold to be used. As a countermeasure to this problem, it is possible to make the heating element itself longer and use only the central part, but in this case another disadvantage arises: the OA equipment becomes larger. Therefore, the problem of the present invention is to provide a heating element with a long effective length relative to the length of the base. [Structure of the Invention] (Means for Solving the Problems) The present invention is intended to provide a heating element having a long effective length relative to the length of the base body. The latitude lines are set at an angle of 90 degrees or less. (Function) If the edge line of the boundary part is set at an angle of 90° or less, the heat generating part can be maintained in a thin state until it connects to the terminal part. By generating heat and compensating for heat loss to the terminals, the effective temperature can be reached up to the closest boundary, increasing the effective length. (Example) The details of the present invention will be explained by referring to an illustrated example. (1)
is an elongated plate-like substrate made of 96% alumina ceramics,
(2) is a grace layer uniformly laminated on the entire upper surface of this substrate (1), (3) is an electric heating element formed on the surface of the grace layer (2), and (4) is this electric heating element (3). It is a glassy protective film that covers the surface of the glass with a grace layer (2). The electric heating element (3) is made by screen printing and baking silver/palladium alloy powder on the surface of the grace layer (2), and has wide terminal parts (32) at both ends of the elongated heating part (3l). The exposed surface of the grace 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 located at the boundary with the terminal part (32). (33)
It is covered up to A silver film (34) is then baked onto the exposed surface of the terminal section (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 θ, that is, the angle at which the side edge of the heat generating portion (3l) 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 part (33) is formed with the narrowest convergence and has the highest resistance. By the way, the dimensions of each part of this heating element are shown below. Base (1)
Length: 300m Width of base (1)
10 ■Thickness of base (1)
1.5-2m Grace layer (2) thickness
Length of 100μ heating part (3l) 28
Center part of 0m heat generating part (31) @2. 5 m heating section (
3l) end @ 1.5■ Heat generating part (31)
Width of border 1.0 - cap of terminal (32)
10m Heating element (3) Thickness of each part: Almost uniformly 10μ Next, the function of the heating element of this embodiment will be explained. WJ terminal section (32). (32) When electricity is applied between the parts, the heat generating part (3l) generates heat, and the heat is transferred to the protective film (4), resulting in a high temperature. Therefore, the width of the heating part (3L) at the center is 2.5 m, which is larger than the width of 1.5 m at both ends.
More heat is generated at both ends than in the center, and this compensates for heat loss in the direction of the terminal (32), making the local temperature uniform. In particular, since the width of the heat generating part (3l) at the boundary part (33) is only 1.0 mL, it has the highest resistance and generates the largest amount of heat, thus reducing heat loss due to heat transfer to the terminal part (32). In addition, the temperature rises to an appropriate temperature up to the area immediately adjacent to the boundary (33), and therefore, even if the length of the heat generating part is the same, the appropriate temperature range is much longer compared to the conventional one with a wider boundary, and the same base A larger effective length can be obtained in terms of body length. In addition, in the above embodiment, the angle of the edge line of the boundary part was set to an acute angle. In the present invention, the same effect can be obtained even at right angles. However, if the angle of the edge line at this boundary is small, the temperature gradient at the boundary becomes large and the wire is likely to break, so it is recommended to apply it to a low-output heating element or to easily replace the heating element when the wire breaks. The idea of doing things like this is embarrassing. In addition, in the present invention, the grace layer is not necessarily necessary; for example, the base itself may be made of a material with high heat insulation properties, and the terminal portion may be expanded only on one side of the heat generating portion. The resistance value is low, the area is large enough to easily connect electric wires, and the angle of the edge line at the boundary is 90°.
It should be less than °. [Effects of the Invention] As described above, in the heating element of the present invention, the angle of the edge line at the boundary between the heat generating part of the electric heating element and the terminal part is set to 90@ or less, so that
The entire heat generating part, especially the boundary area, generates a lot 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 a long effective length relative to the length of the base.
【図面の簡単な説明】[Brief explanation of the drawing]
第１図は本発明の加熱体の一実施例の平面図、第２図は
同じく断面図、第３図は同じく要部拡大平面図である．
（１）・・・基体 （２）・・・グ
レース層（３）・・・電気発熱体 （３ｌ）
・・・発熱部（３２）・・・端子部 （
３３）・・・境界部（３４）・・・銀膜
（４）・・・保護膜（θ）・・・境界部の縁線の
角度FIG. 1 is a plan view of an embodiment of the heating body of the present invention, FIG. 2 is a sectional view of the same, and FIG. 3 is an enlarged plan view of the main parts. (1)...Substrate (2)...Grace layer (3)...Electric heating element (3l)
... Heat generating part (32) ... Terminal part (
33)...Boundary part (34)...Silver film
(4)...Protective film (θ)...Angle of edge line at boundary