JP2537889Z

JP2537889Z -

Info

Publication number: JP2537889Z
Authority: JP
Original assignee: Ricoh Co Ltd
Current assignee: Ricoh Co Ltd
Publication date: 1999-06-07

Description

【考案の詳細な説明】（産業上の利用分野）本考案は、感熱記録紙、熱溶融性カーボンフィルム等を加熱して、記録紙に画
像を形成させるサーマルヘッドを具備したサーマルヘッド・ユニットに関するも
のである。（従来の技術）第４図は従来のサーマルヘッド・ユニットの分解斜視図、第５図は第４図に示
したサーマルヘッド・ユニットの組立斜視図で、１は厚さが５〜８mm程度のアル
ミニウム，鉄鋼，ステンレス鋼等の板材からなる放熱板で、この放熱板１の中程
には４つのネジ孔２が長手方向に配設され、後端にはコネクタ収納用の切欠き１
ａが設けられている。３は、厚さが1.2mm以上のセラミックの基板３ａの図中表
面先端部に多数の微小な発熱体３ｂを長手方向に所定のパターンで配設し、基板
３ａの図中表面後端部に多数の接点３ｃを長手方向に配設したサーマルヘッド、
４は、図中背面先端部に多数の接点４ａを長手方向に配設すると共に、その接点
４ａに接続するリード線パターンを適宜配設したフレキシブル・プリント配線板
（以下「配線板」という）で、この配線板４の後部には４つのネジ挿通孔５が長
手方向に配設され、図中背面後端部にはリード線パターンに接続するコネクタ（
図示しない）が取り付けられている。６は配線板４と放熱板１との間に介装する
フレキシブル・プリント配線板押え（以下「配線板押え」という）で、この配線板押え６の中程には４つのネジ挿通孔７が長手方向に配設されている。８は図
中背面前端部に前部押圧ゴム９を、図中背面後端部に後部押圧ゴム10をそれぞれ
長手方向に取り付けた保護カバーで、この保護カバー８の中程には４つのネジ挿
通孔11が長手方向に配設されている。12は一端をサーマルヘッド制御手段（図示
しない）に接続し、他端を配線板４のコネクタに接続させるコネクタ13に接続し
たハーネス、14は４つのネジ孔２にそれぞれ螺合する４本のねじ、15は組み立て
たサーマルヘッド・ユニットを記録装置等のフレーム（図示しない）の所定の位
置に取り付けるための取付具で、この取付具15は放熱板１の図中背面にネジ止め
される。このように構成された従来例において、サーマルヘッド・ユニットを組み立て
るには、先ず、サーマルヘッド３を放熱板１の前部の所定の位置に載置すると共
に、ネジ挿通孔７が放熱板１のネジ孔２に合うように配線板押え６を放熱板１の
後部に載置する。次に、接点４ａがサーマルヘッド３の接点３ｃに接触し且つネジ挿通孔５が配
線板押え６のネジ挿通孔７に合うように配線板４をサーマルヘッド３及び配線板
押え６に載置した（第５図参照）上、ネジ挿通孔11が配線板４のネジ挿通孔５に
合うように保護カバー８を配線板４の上に載置する。最後に、ネジ挿通孔11，７及び５に挿入したネジ14をネジ孔２に螺合させると
、配線板４の先端部及び後端部が保護カバー８の前部押圧ゴム９及び後部押圧ゴ
ム10によってそれぞれ放熱板１に押圧されて、配線板４の接点４ａがサーマルヘ
ッド３の接点３ｃに圧接して、接続されると同時に、サーマルヘッド３，配線板
押え６及び配線板４が放熱板１に取り付けられる。そして、このように組み立てられたサーマルヘッド・ユニットを取付具15を介
して記録装置等のフレームの所定の位置に取り付けると、取付具15とフレームと
の間に介装したバネ手段（図示しない）によって、基板３ａがプラテン（図示し
ない）に４〜５kg／cm²の圧力で押圧されて、放熱板１と基板３ａとの平面度の
バラツキが吸収される。（考案が解決しようとする課題）ところで、薄板状の基板３ａを焼成すると、反り，凹凸等が生じ易くて、基板３ａの歩留りが悪くなるという問題がある上、その反り，凹凸等のある基板３ａ
と反り，凹凸等のある放熱板１とが接合すると、基板３ａの表面の平面度のバラ
ツキが大きくなって、感熱記録紙，記録紙等への画像の再現性が低下するという
問題があった。又、この問題を解決するために、放熱板１及び基板３ａを平面加工すると、サ
ーマルヘッド・ユニットの製造工程が多くなると共に、製造原価が高くなるとい
う問題を更に生じていた。更に、バネ手段によって４〜５kg／cm²の圧力でプラテンに押圧されている基
板３ａを支持するには、放熱板１の厚さを５〜８mm程度にして放熱板１に所定の
剛性を持たせると共に、基板３ａの厚さを1.2mm以上にして基板３ａに所定の強
度を持たせなければならないので、サーマルヘッド・ユニットが大型化，厚型化
，重量化するという問題を生じていた。更に、バネ手段によって４〜５kg／cm²の圧力で基板３ａが押圧されるプラテ
ンの平面度を維持するには、プラテンの製造原価が高くなるという問題が更に生
じていた。本考案は、このような問題に鑑みてなされたもので、放熱板及びサーマルヘッ
ドの基板に反り，凹凸等を吸収して、サーマルヘッドの基板とプラテンとの接触
面における圧力を均一にするサーマルヘッド・ユニットを提供することを目的と
するものである。（課題を解決するための手段）本考案は、所定のパターンで配設した多数の微小な発熱体を発熱させて記録紙
に画像を形成させるサーマルヘッドが、放熱板に取り付けられているサーマルヘ
ッド・ユニットにおいて、サーマルヘッドは、このサーマルヘッドがフレームの
所定位置にセットされたときに、放熱板を長手方向に彎曲させて放熱板に与えた
弾性力のみにより、プラテンに押圧されるものである。（作用）本考案によれば、放熱板はサーマルヘッドの放熱手段とサーマルヘッドのプラ
テンへの押圧手段との２つの機能を有するため、サーマルヘッド・ユニットの部
品点数が削減されて、サーマルヘッド・ユニットの構成が簡単になり、サーマルヘッド・ユニットが小型，軽量になる。（実施例）以下、図面を参照しながら、本考案の実施例を詳細に説明する。第１図は本考案の位置実施例のサーマルヘッド・ユニットの分解斜視図、第２
図は第１図に示したサーマルヘッド・ユニットの組立斜視図で、16は厚さ1.2mm
の薄い鉄板からなる放熱板で、この放熱板16の前部及び中程には位置決めピン17
が突設され、後部には４つのネジ孔18が長手方向に配設されている。19は放熱板
16の前部両側端の表面側に突設した位置決め足、20は放熱板16の後部両側端の表
面側に突設した取付足、21は、セラミックの基板21ａの図中表面先端部に多数の
微小な発熱体21ｂを長手方向に所定のパターンで配設し、基板21ａの図中表面後
端部に多数の接点21ｃを長手方向に配設したサーマルヘッド、22は、図中背面先
端部に多数の接点22ａを長手方向に配設すると共に、その接点22ａに接続するリ
ード線パターンを適宜配設したフレキシブル・プリント配線板（以下「配線板」
という）で、この配線板22の後部には４つのネジ挿通孔23が長手方向に配設され
、図中表面後端部にはリード線パターンに接続するコネクタ24が取り付けられて
いる。25は、厚さが１〜２mmで、ゴム硬度が30〜40度の弾力性と熱伝導性とを有
するゴム製のパッド、26は図中背面前端部に押庄ゴム27を長手方向に取り付けた
保護カバーで、この保護カバー26の中程には４つのネジ挿通孔28が長手方向に配
設されている。29は４つのネジ孔18にそれぞれ螺合する４本のネジである。このように構成された本実施例において、サーマルヘッド・ユニットを組み立板16の前部の所定の位置に載置した上、前端部及び両側端を位置決めピン17に当
接させたサーマルヘッド21をそのパッド25の上に載置する。熱板16のネジ孔18に合うように配線板22をサーマルヘッド21及び放熱板16に載置
した上、ネジ挿通孔28が配線板22のネジ挿通孔23に合うように保護カバー26を配
線板22の上に載置する。最後に、ネジ挿通孔28及び23に挿入したネジ29をネジ孔18に螺着させると、配
線板22の先端部が保護カバー26の押圧ゴム27によって放熱板16に押圧されて、配線板22の接点22ａがサーマルヘッド21の接点21ｃに圧接して、接続されると同時
に、サーマルヘッド21，配線板22及びパッド25が放熱板16に取り付けられる（第
２図参照）。又、本実施例においては、放熱板16を鉄板で作成する例で説明したが、放熱板
16を格子状に形成して（第３図参照）、放熱板16の長手方向に剛性を持たせるこ
とにより、放熱板16を合成樹脂で作成することができる。更に、本実施例においては、発熱体21ｂによって加熱された基板21ａの熱を放
熱板16に伝えて大気中に単に放熱するために、パッド25に熱伝導性のゴムを使用
する例で説明したが、発熱体21ｂによって加熱された基板21ａの熱の一部を発熱
体21ｂの余熱用としてパッド25に蓄え、残りの熱を放熱板16に伝えて大気中に放
熱するために、パッド25に熱伝導性の発泡ゴムを使用してもよい。（考案の効果）以上説明したように、本考案によれば、放熱板はサーマルヘッドの放熱手段と
サーマルヘッドのプラテンへの押圧手段との２つの機能を有するため、サーマル
ヘッド・ユニットの部品点数が削減されて、サーマルヘッド・ユニットの構成が
簡単になり、サーマルヘッド・ユニットが小型，軽量になるという効果を奏する
。DETAILED DESCRIPTION OF THE INVENTION (Industrial application field) The present invention relates to a thermal head unit having a thermal head for forming an image on a recording paper by heating a thermosensitive recording paper, a heat-fusible carbon film or the like. Things. (Prior Art) FIG. 4 is an exploded perspective view of a conventional thermal head unit, and FIG. 5 is an assembled perspective view of the thermal head unit shown in FIG. 4, where 1 is about 5 to 8 mm thick. A heat radiating plate made of a plate material such as aluminum, steel, stainless steel, or the like. Four screw holes 2 are provided in the middle of the heat radiating plate 1 in the longitudinal direction, and a notch 1 for housing a connector is provided at the rear end.
a is provided. 3, a number of minute heating elements 3b are arranged in a predetermined pattern in the longitudinal direction at the front end of the surface of the ceramic substrate 3a having a thickness of 1.2 mm or more in the drawing, and at the rear end of the front surface of the substrate 3a in the drawing. A thermal head in which a large number of contacts 3c are arranged in the longitudinal direction,
Reference numeral 4 denotes a flexible printed wiring board (hereinafter, referred to as "wiring board") in which a number of contacts 4a are disposed in the longitudinal direction at the rear end in the figure and a lead wire pattern connected to the contacts 4a is appropriately disposed. Four screw insertion holes 5 are provided in the rear part of the wiring board 4 in the longitudinal direction, and a connector (see FIG. 4) for connecting to a lead wire pattern is provided at the rear end of the rear surface.
(Not shown). Reference numeral 6 denotes a flexible printed wiring board retainer (hereinafter, referred to as a “wiring board retainer”) interposed between the wiring board 4 and the heat sink 1, and four screw insertion holes 7 are provided in the middle of the wiring board retainer 6. It is arranged in the longitudinal direction. Reference numeral 8 denotes a protective cover in which a front pressing rubber 9 is attached to a front end of a rear surface in the drawing and a rear pressing rubber 10 is attached to a rear end of the rear in the drawing, and four screws are inserted in the middle of the protective cover 8. A hole 11 is provided in the longitudinal direction. Reference numeral 12 denotes a harness having one end connected to a thermal head control means (not shown), and the other end connected to a connector 13 for connecting the other end to a connector of the wiring board 4. Fourteen screws four are screwed into the four screw holes 2 respectively. Reference numeral 15 denotes a fixture for attaching the assembled thermal head unit to a predetermined position of a frame (not shown) of a recording apparatus or the like. The fixture 15 is screwed to the back of the heat sink 1 in the figure. In order to assemble the thermal head unit in the conventional example configured as described above, first, the thermal head 3 is placed at a predetermined position in front of the radiator plate 1 and the screw insertion hole 7 is inserted into the radiator plate 1. The wiring board retainer 6 is placed on the rear part of the heat sink 1 so as to fit the screw hole 2. Next, the wiring board 4 was placed on the thermal head 3 and the wiring board holder 6 such that the contact 4a was in contact with the contact 3c of the thermal head 3 and the screw insertion hole 5 was aligned with the screw insertion hole 7 of the wiring board holder 6. (See FIG. 5.) The protective cover 8 is placed on the wiring board 4 so that the screw insertion holes 11 match the screw insertion holes 5 of the wiring board 4. Finally, when the screw 14 inserted in the screw insertion holes 11, 7 and 5 is screwed into the screw hole 2, the front end and the rear end of the wiring board 4 become the front pressing rubber 9 and the rear pressing rubber 9 of the protective cover 8. The contact 4a of the wiring board 4 is pressed against the contact 3c of the thermal head 3 by being pressed by the heat radiating plate 1 and connected thereto, and at the same time, the thermal head 3, the wiring board presser 6 and the wiring board 4 are connected to the heat radiating plate. Attach to 1. When the thus assembled thermal head unit is attached to a predetermined position of a frame such as a recording apparatus via the attachment 15, a spring means (not shown) interposed between the attachment 15 and the frame. As a result, the substrate 3a is pressed against a platen (not shown) at a pressure of 4 to 5 kg / cm ² , and the unevenness of the flatness between the heat sink 1 and the substrate 3a is absorbed. (Problems to be Solved by the Invention) When the thin plate-shaped substrate 3a is fired, there is a problem that warpage and unevenness are likely to occur, and the yield of the substrate 3a is deteriorated. 3a
When the heat radiating plate 1 having a warp, irregularities, etc. is joined, the unevenness of the flatness of the surface of the substrate 3a becomes large, and there is a problem that the reproducibility of an image on thermosensitive recording paper, recording paper or the like is reduced. . Further, when the heat sink 1 and the substrate 3a are planarized to solve this problem, the number of manufacturing steps of the thermal head unit is increased and the manufacturing cost is further increased. Further, in order to support the substrate 3a pressed against the platen at a pressure of 4 to 5 kg / cm ² by the spring means, the thickness of the heat sink 1 is set to about 5 to 8 mm so that the heat sink 1 has a predetermined rigidity. At the same time, the thickness of the substrate 3a must be set to 1.2 mm or more to give the substrate 3a a predetermined strength. This causes a problem that the thermal head unit becomes large, thick, and heavy. Further, in order to maintain the flatness of the platen on which the substrate 3a is pressed at a pressure of 4 to 5 kg / cm ² by the spring means, there has been a further problem that the manufacturing cost of the platen is increased. The present invention has been made in view of such a problem, and a thermal head that absorbs warpage, irregularities, and the like in a heat sink and a substrate of a thermal head to make a pressure at a contact surface between the substrate of the thermal head and a platen uniform. It is an object to provide a head unit. (Means for Solving the Problems) The present invention relates to a thermal head in which a large number of minute heating elements arranged in a predetermined pattern generate heat to form an image on recording paper, and the thermal head is attached to a heat radiating plate. In the unit, when the thermal head is set at a predetermined position on the frame, the thermal head is pressed against the platen by only the elastic force applied to the heat radiating plate by bending the heat radiating plate in the longitudinal direction. . (Operation) According to the present invention, since the heat radiating plate has two functions of the heat radiating means of the thermal head and the pressing means of the thermal head against the platen, the number of components of the thermal head unit is reduced, and the thermal head unit is reduced. The structure of the unit is simplified, and the thermal head unit becomes smaller and lighter. Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings. FIG. 1 is an exploded perspective view of a thermal head unit according to an embodiment of the present invention, FIG.
The figure is an assembled perspective view of the thermal head unit shown in FIG.
A radiating plate made of a thin iron plate with positioning pins 17 at the front and middle of the radiating plate 16.
, And four screw holes 18 are provided in the rear portion in the longitudinal direction. 19 is a heat sink
Positioning feet protruding from the front side of the front side of the heat sink 16, mounting feet protruding from the front side of the rear side of the heat radiating plate 20, and a number of mounting feet 21 on the front surface of the ceramic substrate 21 a in FIG. Is a thermal head in which minute heating elements 21b are arranged in a predetermined pattern in the longitudinal direction, and a large number of contacts 21c are arranged in the longitudinal direction at the rear end of the surface of the substrate 21a in the figure. A flexible printed wiring board (hereinafter referred to as a “wiring board”) in which a number of contacts 22a are arranged in the longitudinal direction and a lead wire pattern connected to the contacts 22a is appropriately arranged.
At the rear of the wiring board 22, four screw insertion holes 23 are provided in the longitudinal direction, and a connector 24 connected to a lead wire pattern is attached to the rear end of the surface in the figure. 25 is a rubber pad having a thickness of 1 to 2 mm and a rubber hardness of 30 to 40 degrees and having elasticity and thermal conductivity, and 26 is a longitudinally attached push-in rubber 27 at the front end of the back in the figure. In the middle of the protective cover 26, four screw insertion holes 28 are provided in the longitudinal direction. Reference numeral 29 denotes four screws which are screwed into the four screw holes 18, respectively. In the present embodiment configured as described above, the thermal head unit is assembled. The thermal head 21, which is placed at a predetermined position in the front part of the plate 16, and whose front end and both ends are in contact with the positioning pins 17, is placed on the pad 25. The wiring board 22 is placed on the thermal head 21 and the heat radiating plate 16 so as to match the screw holes 18 of the heating plate 16, and the protective cover 26 is wired so that the screw insertion holes 28 match the screw insertion holes 23 of the wiring board 22. Place on plate 22. Finally, when the screw 29 inserted into the screw insertion holes 28 and 23 is screwed into the screw hole 18, the distal end of the wiring board 22 is pressed by the heat radiation plate 16 by the pressing rubber 27 of the protective cover 26, and the wiring board 22 The contact 22a is pressed into contact with the contact 21c of the thermal head 21, and at the same time, the thermal head 21, the wiring board 22, and the pad 25 are attached to the heat radiating plate 16 (see FIG. 2). Further, in the present embodiment, the example in which the heat radiating plate 16 is made of an iron plate has been described.
The heat radiating plate 16 can be made of a synthetic resin by forming the radiating plate 16 in a lattice shape (see FIG. 3) so as to have rigidity in the longitudinal direction of the radiating plate 16. Further, in the present embodiment, an example in which a heat conductive rubber is used for the pad 25 in order to transmit the heat of the substrate 21a heated by the heating element 21b to the radiator plate 16 and simply radiate the heat to the atmosphere has been described. However, a portion of the heat of the substrate 21a heated by the heating element 21b is stored in the pad 25 as residual heat of the heating element 21b, and the remaining heat is transmitted to the heat radiating plate 16 to be radiated to the air. A thermally conductive foamed rubber may be used. (Effects of the Invention) As described above, according to the present invention, since the heat radiating plate has two functions of the heat radiating means of the thermal head and the pressing means of the thermal head against the platen, the number of parts of the thermal head unit is reduced. Is reduced, the structure of the thermal head unit is simplified, and the thermal head unit is reduced in size and weight.

【図面の簡単な説明】第１図は本考案の一実施例のサーマルヘッド・ユニットの分解斜視図、第２図
は第１図に示したサーマルヘッド・ユニットの組立斜視図、第３図は本考案の一
実施例のサーマルヘッド・ユニットにおける放熱板の他の具体例の斜視図、第４
図は従来のサーマルヘッド・ユニットの分解斜視図、第５図は第４図に示したサ
ーマルヘッド・ユニットの組立斜視図である。 16…放熱板、 21…サーマルヘッド、 21ｂ…発熱体、 25…パッド。BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is an exploded perspective view of a thermal head unit according to an embodiment of the present invention, FIG. 2 is an assembled perspective view of the thermal head unit shown in FIG. 1, and FIG. 4 is a perspective view of another specific example of the heat sink in the thermal head unit according to the embodiment of the present invention, FIG.
The figure is an exploded perspective view of a conventional thermal head unit, and FIG. 5 is an assembled perspective view of the thermal head unit shown in FIG. 16: heat sink, 21: thermal head, 21b: heating element, 25: pad.

Claims

[Claims for Utility Model Registration] In a thermal head unit mounted on a heat radiating plate, a thermal head for generating an image on recording paper by generating heat from a large number of minute heating elements arranged in a predetermined pattern is provided. The thermal head is set at a predetermined position on the frame.
The thermal head unit is characterized in that when the heat radiating plate is bent in the longitudinal direction, the plate is pressed against the platen only by the elastic force applied to the heat radiating plate.