JPH10301410A5

JPH10301410A5 -

Info

Publication number: JPH10301410A5
Application number: JP1997111154A
Authority: JP
Filing date: 1997-04-28
Publication date: 2005-04-07

Description

従来のフィルム加熱方式の加熱装置について、本発明に係る図８を援用して概説すると、通常、薄肉の耐熱性フィルム１と、このフィルム１の一方面側に固定支持して配置された加熱体（ヒータ）３と、他方面側にヒータ３に対向して配置された、ヒータ３に対してフィルム１を介して被加熱部材を密着させる加圧部材４を有している。ヒータ３は被加熱部材としての記録材Ｐの搬送方向に直交する方向に延びる細長い棒状をなしている。 8 of the present invention, a conventional film heating type heating device will be generally described as having a thin heat-resistant film 1, a heating element (heater) 3 fixedly supported on one side of the film 1 , and a pressure member 4 arranged on the other side opposite the heater 3 to bring the heated member into close contact with the heater 3 via the film 1. The heater 3 is shaped like a long, thin rod extending in a direction perpendicular to the conveyance direction of the recording material P as the heated member.

フィルム１を挟んでヒータ３と加圧部材４との圧接で形成される圧接ニップ部のフィルム１と加圧部材４との間に、被加熱部材、像加熱装置にあってはトナー像を形成担持させた記録材Ｐを導入して通過させることにより、記録材Ｐの顕画像担持体面がフィルム１を介してヒータ３で加熱され、未定着画像に熱エネルギーを付与し、トナーが軟化、溶融して画像の加熱定着がなされる。 A heated member, in the case of an image heating device, a recording material P carrying a toner image, is introduced and passed between the film 1 and pressure member 4 in the pressure nip formed by the heater 3 and pressure member 4 sandwiching the film 1. The visible image carrying surface of the recording material P is heated by the heater 3 via the film 1, imparting thermal energy to the unfixed image, softening and melting the toner, thereby heat-fixing the image.

図１０は別の従来例の加熱体３の一部切欠き表面図と裏面図である。この加熱体３は、発熱体の折り返しパターン１５をスルーホール１８を介し裏面と導通をとり、裏面にＡＣ電極を形成したものである。 10 shows a partially cutaway front and back view of another conventional heating element 3. In this heating element 3 , the folded pattern 15 of the heating element is electrically connected to the back surface via a through hole 18, and an AC electrode is formed on the back surface.

本出願に係る第７の発明の画像形成装置は、記録材に画像を形成する画像形成部と、記録材に画像を加熱定着する第１から６のいずれか１つに記載の発明の加熱定着装置を具備することを特徴とする。 The seventh invention of the present application is an image forming apparatus characterized by comprising an image forming section that forms an image on a recording material, and a heat fixing device of any one of the first to sixth inventions that heat fixes the image on the recording material.

【００２５】
【発明の実施の形態】
［実施形態１］
図８に本発明に係るテンションレスタイプのフィルム加熱定着装置の一例の概略断面を示す。同図において、１はエンドレスの耐熱性フィルムであり、加熱体３を含むフィルム１のガイド部材でもある加熱体支持体２に外嵌させてある。このエンドレスの耐熱フィルム１の内周長と加熱体を含む加熱体支持体２の外周長はフィルム１の方を例えば３ｍｍ程度大きくしてあり、したがってフィルム１は加熱体支持体２に対し周長が余裕をもってルーズに外嵌している。 [0025]
[Embodiment of the Invention]
[Embodiment 1]
8 shows a schematic cross section of an example of a tensionless type film heat fixing device according to the present invention. In the figure, reference numeral 1 denotes an endless heat-resistant film, which is fitted around a heater support 2 that also serves as a guide member for the film 1 including a heater 3. The inner periphery of the endless heat-resistant film 1 is larger than the outer periphery of the heater support 2 including the heater, by, for example, about 3 mm, so that the film 1 fits loosely around the heater support 2 with a margin of circumferential length.

加熱体（ヒータ）３は、後述するように、横長薄板状のセラミック基板と、その基板面に基板長手にそって形成具備させた抵抗発熱体を基本構成体としてなり、抵抗発熱体への電力供給により迅速に発熱・昇温して温調系で所定の定着温度に温度管理される。この加熱体３は上記加熱体支持体（ホルダ）２に対して該支持体２の下面に長手に沿って形成具備させた溝内に嵌め入れて保持させてある。 As will be described later, the heating element (heater) 3 basically comprises a horizontally long, thin ceramic substrate and a resistance heating element formed on the surface of the substrate along the length of the substrate, and when power is supplied to the resistance heating element, it quickly generates heat and rises in temperature, and the temperature is controlled to a predetermined fixing temperature by a temperature control system. This heating element 3 is held by fitting it into a groove formed along the length of the underside of the heating element support (holder) 2 .

４は加熱体３との間でフィルム１を挟んでニップＮを形成し、フィルム１を駆動する回転体としての加圧ローラであり、芯金４−ａとシリコンゴム等の離型性の良い耐熱ゴム４−ｂからなり、芯金４−ａの端部より不図示の手段により駆動する。 Reference numeral 4 denotes a pressure roller as a rotating body that sandwiches the film 1 between itself and the heater 3 to form a nip N and drives the film 1. The pressure roller 4 is made of a core 4-a and heat-resistant rubber 4-b such as silicone rubber that has good releasability, and is driven from the end of the core 4-a by means not shown.

加熱体３上に設けられたサーミスタ５の出力をＡ／Ｄ変換しＣＰＵ１０に取り込みその情報をもとにトライアック１１により加熱体３に通電するＡＣ電圧を位相、波形制御等のパルス幅変調をかけ、加熱体通電電力を制御することで行う。上記例は、テンションレスタイプであるが、本発明では、駆動ローラ、テンションローラ、加熱体にフィルムを巻回するテンションタイプの加熱装置に実施することもできる。 The output of the thermistor 5 provided on the heater 3 is A/D converted and input to the CPU 10, and based on this information, the AC voltage supplied to the heater 3 is pulse-width modulated by the triac 11, including phase and waveform control, to control the power supplied to the heater. The above example is of a tensionless type, but the present invention can also be applied to a tension-type heating device in which a film is wound around a drive roller, tension roller, and heater.

次に、上記加熱装置を具備する画像形成装置の１例について、図７により説明すると、１０１はレーザユニットで、該ユニット１０１から放射されるレーザ光はミラー１０２により反射され、電子写真感光体等の感光ドラム１０３を照射、露光して感光ドラム上に静電潜像を形成する。感光ドラム１０３の表面は一次帯電器１０４により予め一様に帯電されている。容器１０５内に収容された現像剤であるトナー１０６は、現像スリーブ１０７により担持搬送されて、感光ドラム１０３上の前記潜像を現像してトナー像化する。記録剤積載手段であるカセット１０８に積載された普通紙等の記録材１０９は給紙ローラ１１０により転写部に搬送され、感光ドラム１０３上のトナー像は転写手段１１１により記録材１０９に転写される。転写がされた記録材１０９は定着手段１１２に搬送され、そこでトナー像が記録材１０９に加熱定着される。 Next, an example of an image forming apparatus equipped with the above-described heating device will be described with reference to FIG. 7 . Reference numeral 101 denotes a laser unit. Laser light emitted from the unit 101 is reflected by a mirror 102 and irradiates and exposes a photosensitive drum 103, such as an electrophotographic photosensitive member, to form an electrostatic latent image on the photosensitive drum. The surface of the photosensitive drum 103 is uniformly charged in advance by a primary charger 104. Toner 106, which is a developer contained in a container 105, is carried and transported by a developing sleeve 107 and develops the latent image on the photosensitive drum 103 into a toner image. A recording material 109, such as plain paper, loaded in a cassette 108, which is a recording material loading means, is transported to a transfer section by a paper feed roller 110, and the toner image on the photosensitive drum 103 is transferred to the recording material 109 by transfer means 111. The transferred recording material 109 is transported to a fixing means 112, where the toner image is fixed to the recording material 109 by heat.

図１は本発明の第１の実施形態で用いた加熱体３の一部切欠き表面図と裏面図である。ここで、２０１が良熱伝導性ペーストによるパターンである。図１において図９と同一符号は同一部分を示す。図９で説明した加熱体３と異なるところは、セラミック基板８の裏面の、封筒等の小サイズ紙の非通紙域部に、熱伝導の良好な熱伝導パターン２０１が設けられていることである。該熱伝導パターン２０１は、熱伝導度の大きな金属ペーストで形成され、本実施形態においては、Ａｇペーストを基板８の裏面に印刷、形成されている。図１の例は、通紙基準が端部基準の例で、熱伝導パターン２０１は、基板８の一側の小サイズ紙の非通紙域部に形成されており、該パターン２０１の中央端部は小サイズの記録材の通紙領域近傍にあり、パターンの側端部は基板８裏面の一側端部近傍にあり、また該パターンの中央側端部は、記録材の通紙領域に一部オーバラップしてもよく、しなくてもよい。 FIG. 1 shows a partially cutaway front and rear view of the heater 3 used in the first embodiment of the present invention. Here, 201 denotes a pattern made of a highly thermally conductive paste. The same reference numerals in FIG. 1 as in FIG. 9 indicate the same parts. The heater 3 described in FIG. 9 differs from the heater 3 described in FIG. 9 in that a highly thermally conductive pattern 201 is provided on the back surface of the ceramic substrate 8 in a non-paper-passing area for small-sized paper such as envelopes. The thermally conductive pattern 201 is formed of a metal paste with high thermal conductivity. In this embodiment, an Ag paste is printed and formed on the back surface of the substrate 8. The example in FIG. 1 is an example in which the paper passing reference is an edge reference, and the thermally conductive pattern 201 is formed on one side of the substrate 8 in a non-paper-passing area for small-sized paper. The central end of the pattern 201 is located near the paper passing area for small-sized recording materials, and the side end of the pattern is located near one side edge of the back surface of the substrate 8. The central end of the pattern may or may not partially overlap the paper passing area for recording materials.

図３は第３の実施形態の裏面図である。この実施形態では、通紙基準が中央である系を用いている。本実施形態の定着器構成においては、小サイズの厚紙を中央部に通紙した際に両端が浮く可能性があり、その両端の非通紙域で、異常昇温が発生する。しかし、裏面には、少なくとも一方にサーミスタ電極５が形成されるため、このサーミスタ電極パターン側に熱伝導パターンを形成することはできない。したがってこのサーミスタ電極パターンを利用した構成をとることが好ましい。 FIG. 3 is a rear view of the third embodiment. This embodiment uses a system in which the paper feed reference is the center. In the fixing device configuration of this embodiment, when small-sized cardboard is fed through the center, both ends may lift, causing abnormal temperature rise in the non-paper-feed areas on both ends. However, because the thermistor electrode 5 is formed on at least one side of the rear surface, it is not possible to form a heat conduction pattern on the side of this thermistor electrode pattern. Therefore, it is preferable to use a configuration that utilizes this thermistor electrode pattern.

本実施形態においては、ＡＣ電極側には実施形態１と同様の熱伝導パターン２０１を形成させ、サーミスタ５のＤＣ電極側には、ＤＣ電極パターン２０３を、従来ヒータよりも広く形成してある。特に、小サイズ通紙時に紙のエッジがかかり、ヒータユニットと加圧ローラが浮く範囲に広く形成した。本実施形態のヒータを用いて実施形態１、２に述べた過酷試験モードにおけるヒータ割れは、実施形態１に記載のヒータと同様、１０サイクル以上でもヒータ割れは発生せず、従来ヒータに比べて、ヒータ割れに対するマージンを確保することができた。 In this embodiment, a heat conduction pattern 201 similar to that of embodiment 1 is formed on the AC electrode side, and a DC electrode pattern 203 is formed on the DC electrode side of the thermistor 5 , which is wider than that of conventional heaters. In particular, it is formed widely in an area where the edge of the paper catches when small-sized paper is passed through, causing the heater unit and pressure roller to float. When using the heater of this embodiment in the severe test mode described in embodiments 1 and 2, no heater cracking occurred even after 10 cycles or more, just like the heater described in embodiment 1, and a margin against heater cracking could be secured compared to conventional heaters.

さらに表４は本実施形態のヒータを用いた場合の非通紙域の過昇温部のヒータ表面温度を測定したものである。この結果から明らかなように本実施形態の構成をとることにより、従来構成ヒータに比べＴ１、ΔＴともに低く押えることができ、ヒータ割れに対してさらに有利になった。本実施形態では、まず、ヒータ基板裏面に良熱伝導パターンを形成したことで、ヒータユニットと加圧ローラが浮いた場合にも、熱をセラミック基板上で、分散させ、局所的な過昇温を防ぐことができ、さらに熱伝導が良いために基板の長手方向、幅方向それぞれに拡散することで、基板上の温度勾配を小さくでき、ヒータの熱ストレスを軽減させることでヒータ割れを防ぐことが可能であり、さらに、その過昇温部からその近傍にかけて、耐熱性高分子層を、本実施形態においてはポリイミドフィルム層３０１を設けることで、ヒータの熱容量が増えると同時に、ヒータからヒータステーへの熱伝達を促進させ、ヒータの過昇温部の温度をさらに低く押えることができ、同時に、発熱体上とそれ以外の基板部の温度差も小さくできることで、ヒータ割れに対して非常に効果があることがわかった。 Furthermore, Table 4 shows the heater surface temperature measured at the overheated portion in the non-paper passing area when the heater of this embodiment was used. As is clear from these results, the configuration of this embodiment allows both T1 and ΔT to be kept lower than with conventional heater configurations, further improving heater crack prevention. In this embodiment, first, by forming a highly thermally conductive pattern on the backside of the heater substrate, heat is dispersed across the ceramic substrate, preventing local overheating even when the heater unit and pressure roller are lifted. Furthermore, due to the excellent thermal conductivity, heat is diffused both longitudinally and transversely across the substrate, reducing the temperature gradient across the substrate and reducing the thermal stress on the heater, thereby preventing heater cracking. Furthermore, by providing a heat-resistant polymer layer (polyimide film layer 301 in this embodiment) from the overheated portion to its vicinity, the heater's thermal capacity is increased and heat transfer from the heater to the heater stay is promoted, further reducing the temperature of the overheated portion of the heater. At the same time, the temperature difference between the heating element and the rest of the substrate is reduced, demonstrating significant effectiveness in preventing heater cracking.

Claims

A heat fixing device that applies thermal energy from the heating element to the recording material by passing the recording material carrying an unfixed image through a nip between a long, rod-shaped heating element extending perpendicular to the conveying direction of the recording material and a pressure member that presses against the heating element, and thereby thermally fixes the recording material, characterized in that a heat conduction pattern is formed on the back surface of the heating element.

2. The heat fixing device according to claim 1 , wherein the heat conduction pattern is formed on the rear surface of the heating body in a non-sheet passing area.

3. The heat fixing device according to claim 1, wherein the heat conduction pattern is formed by an electrode for detecting the temperature of the heater.

4. The heat fixing device according to claim 1, wherein the heat conductive pattern on the rear surface of the heating element is made of an Ag-based material.

5. The heat fixing device according to claim 4 , wherein a heat-resistant polymer layer is formed on the heat conductive pattern formed on the rear surface of the heating element.

6. The heat fixing device according to claim 5 , wherein the heat-resistant polymer layer is a polyimide film.

7. An image forming apparatus comprising: an image forming section for forming an image on a recording material; and a heat fixing device according to claim 1 for fixing the image on the recording material by heat.