JP3926535B2

JP3926535B2 - Fixing device

Info

Publication number: JP3926535B2
Application number: JP2000101667A
Authority: JP
Inventors: 栄二沢村
Original assignee: Ricoh Co Ltd
Current assignee: Ricoh Co Ltd
Priority date: 2000-04-04
Filing date: 2000-04-04
Publication date: 2007-06-06
Anticipated expiration: 2020-04-04
Also published as: JP2001282025A

Description

【０００１】
【発明の属する技術分野】
本発明は、円筒状金属基体（円筒状芯金）の内周面に円筒状絶縁層体を介して円筒状発熱層体が設けられ、この円筒状発熱層体の内周面に円筒状絶縁層体を介してこの円筒状絶縁層体と共に円筒状発熱層体を円筒状金属基体に圧接する円筒状バネ体が設けられた加熱ローラを有する定着装置に関するものである。
【０００２】
【従来の技術】
従来から、定着装置には、図１に示すように、加圧ローラ（図示を略す）と協働して未定着トナー像を記録紙に定着する加熱ローラ１が円筒状金属基体２から構成され、この円筒状金属基体２の内周面には円筒状絶縁層体３を介して円筒状発熱層体４が設けられ、この円筒状発熱層体４の内周面には円筒状絶縁層体５を介して円筒状バネ体６が設けられ、その円筒状金属基体２の外周面には離型層７が設けられたものが知られている。
【０００３】
その円筒状発熱層体４は例えば発熱抵抗パターンから構成されている。その円筒状発熱層体４への通電構造は例えば以下のようになっている。
【０００４】
すなわち、定着装置には非導電性の中空状樹脂製ブラシホルダが設けられている。円筒状金属基体２にはその側端開口部に給電キャップ部材が設けられている。その中空状樹脂製ブラシホルダ内には摺動可能の給電ブラシが設けられ、この給電ブラシはバネ部材によってその給電キャップ部材に圧接され、中空状樹脂製ブラシホルダ内に配設された導線を介して給電キャップ部材に通電するようにされている。
【０００５】
【発明が解決しようとする課題】
しかしながら、この従来の加熱ローラ１では、円筒状発熱層体４の内周面側に絶縁層体５を介して円筒状バネ体６が接触する構成であるので、円筒状発熱層体４の熱が絶縁層体５を介して円筒状バネ体６に向かって逃げ、その結果、定着装置の立ち上がり時間が遅いという問題がある。
【０００６】
図２は円筒状発熱層体４を接着剤によって円筒状金属基体２の内周面に固着する構成の加熱ローラの立ち上がり時間と円筒状発熱層体４を円筒状バネ体６によって円筒状金属基体２の内周面に圧接する構成の加圧ローラ１の立ち上がり時間とを比較したグラフ図であり、この図２に示すように、円筒状発熱層体４を円筒状バネ体６によって円筒状金属基体２の内周面に圧接する構成の加圧ローラ１の外周面が１８０度Cに達するまでの立ち上がり時間T１は円筒状発熱層体４を接着剤によって円筒状金属基体２の内周面に固着する構成の加熱ローラの立ち上がり時間T2よりも遅く、従来の円筒状発熱層体４を円筒状バネ体６によって円筒状金属基体２の内周面に圧接する構成の加圧ローラ１では、立ち上がりに時間がかかり過ぎると共に電力量もかかり過ぎるという問題がある。
【０００７】
本発明は、上記の事情に鑑みて為されたもので、その目的は、円筒状発熱層体を円筒状バネ体によって円筒状金属基体の内周面に圧接する構成の加熱ローラを有する定着装置であっても、その立ち上がり時間を短縮することのできる定着装置を提供することにある。
【０００８】
【課題を解決するための手段】
請求項１に記載の定着装置は、加圧ローラと協働して未定着トナー像を記録紙に定着する加熱ローラを有し、該加熱ローラが円筒状金属基体から構成され、該円筒状金属基体の内周面には円筒状耐熱絶縁層体を介して円筒状発熱層体が設けられ、該円筒状発熱層体の内周面には円筒状耐熱絶縁層体を介して円筒状バネ体が設けられた定着装置において、
前記円筒状発熱層体と前記円筒状バネ体との間に円筒状断熱層体が設けられ、前記円筒状金属基体の内周面に接触する円筒状耐熱絶縁層体の軸方向全長は前記円筒状発熱層体の軸方向全長よりも長くてかつ前記円筒状金属基体の軸方向全長よりも短く、前記円筒状発熱層体と当該円筒状発熱層体と前記円筒状バネ体との間に存在する円筒状耐熱絶縁層体との軸方向全長は前記円筒状バネ体の軸方向全長よりも短くされて前記円筒状発熱層体の両端部に給電接触部が設けられ、前記円筒状金属基体の両端部には前記給電接触部に接触される給電キャップ部材が設けられ、前記円筒状バネ体の両端には切片部が設けられていると共に前記円筒状発熱層体と前記円筒状バネ体との間に存在する円筒状耐熱絶縁層体の両端と前記円筒状耐熱断熱層体の両端とに切片部が設けられ、円筒状バネ体の切片部は円筒状金属基体の内周端面部まで延長されて該内周端面部に固定手段によって固定され、前記円筒状耐熱絶縁層体の切片部と前記円筒状断熱層体の切片部とは前記円筒状バネ体の切片部が前記円筒状発熱層体の給電接触部に接触するのを防止することを特徴とする。
【０００９】
請求項１に記載の発明によれば、円筒状発熱層体と円筒状バネ体との間に円筒状断熱層体が設けられているので、円筒状発熱層体の熱が円筒状バネ体に伝わりにくくなり、もっぱら円筒状発熱層体の熱が円筒状金属基体の外周面に導かれるので、円筒状発熱層体を円筒状バネ体によって円筒状金属基体の内周面に圧接する構成の加熱ローラを有する定着装置であっても、その立ち上がり時間を短縮することができる。
また、加熱ローラの回転中に円筒状バネ体が円筒状金属基体のスラスト方向に移動して円筒状発熱層体又は給電キャップ部材に接触してショートするという現象を防止できる。
【００１０】
請求項２に記載の定着装置は、前記円筒状断熱層体の厚さが２ｍｍ以下であることを特徴とする。
【００１１】
請求項２に記載の発明によれば、円筒状断熱層体に要する材料費が必要以上に嵩むことなく効率よく定着装置の立ち上がり時間を早くすることができる。
【００１４】
【発明の実施の形態】
図３において、１０は加熱ローラである。この加熱ローラ１０は、円筒状金属基体１１から構成されている。この円筒状金属基体１１は鉄、アルミニウム、銅、ステンレス等の金属材料を用いて形成される。
【００１５】
この円筒状金属基体１１の外周面には離型層１２が設けられている。その離型層１２はその層厚が例えば１０μｍ乃至３０μｍであり、PFA又はPTFE材料を円筒状金属基体１１の外周面にコーティングすることによって形成される。
【００１６】
円筒状金属基体１１の内周面には円筒状耐熱絶縁層体１３を介して円筒状発熱層体１４が設けられている。その円筒状耐熱絶縁層体１３には例えばポリイミド等の樹脂材料が用いられている。その円筒状発熱層体１４の内周面には円筒状耐熱絶縁層体１５が設けられている。その円筒状発熱層体１４は例えばステンレス等の金属箔（発熱抵抗パターン）から構成され、その層厚は例えば２５μｍ乃至１００μｍである。
【００１７】
その円筒状耐熱絶縁層体１５の材料には円筒状耐熱絶縁層体１３と同じ材料が用いられ、これらの円筒状耐熱絶縁層体１３，１５の層厚は例えば２５μｍ乃至１００μｍである。これらの円筒状耐熱絶縁層体１３はシート又はコーティングを円筒状発熱層体１４の両面に施すことによって形成される。
【００１８】
円筒状発熱層体１４の内周面には円筒状耐熱絶縁層体１５を介して円筒状耐熱断熱層体１６が設けられている。この円筒状耐熱断熱層体１６は５００度C程度の高温でも発火しない材料からなるフェルト部材、例えば商品名ノーメックス、SCペーパーのような材料を用いて形成される。その円筒状耐熱断熱層体１６の層厚は２ｍｍ以下であることが望ましい。その理由については後述する。
【００１９】
その円筒状耐熱断熱層体１６の内周面には円筒状バネ体１７が設けられている。円筒状耐熱絶縁層体１３と円筒状発熱層体１４と円筒状耐熱絶縁層体１５と円筒状耐熱断熱層体１６とは円筒状バネ体１７によって円筒状金属基体１１の内周面に圧接される。その円筒状バネ体１７は長方形状のSUS板を丸めることによって形成される。その円筒状バネ体１７の層厚は例えば５０μｍないし２００μｍである。
【００２０】
図４に示すように、円筒状耐熱絶縁層体１３の軸方向全長は円筒状発熱層体１４の軸方向全長よりも長く、その円筒状発熱層体１４の端面よりも少なくとも２.５ｍｍ以上突出している。円筒状耐熱断熱層体１６の軸方向全長と円筒状耐熱絶縁層体１５の軸方向全長とはほぼ同じで円筒状発熱層体１４の軸方向全長よりも短く、円筒状発熱層体１４の両端部には給電接触部１４a、１４aが設けられている。円筒状金属基体１１の両端開口部には図示を略す給電キャップ部材が嵌合され、この給電キャップ部材がその給電接触部１４a、１４aに接触される。この給電接触部１４a、１４aの軸方向の幅は例えば２ｍｍ以上である。円筒状バネ体１７の軸方向全長は円筒状耐熱絶縁層体１５の軸方向全長よりも短く、その円筒状バネ体１７の端面から円筒状耐熱絶縁層体１５の端面までの長さを２.５ｍｍ以上とするのが絶縁を図るうえで望ましい。
【００２１】
この加熱ローラ１０は、図５に示すように、円筒状金属基体１１の内周面に円筒状耐熱絶縁層体１３、円筒状発熱層体１４、円筒状耐熱絶縁層体１５、円筒状耐熱断熱層体１６を配設した後、円筒状耐熱断熱層体１６の内径よりも縮径された円筒状バネ体１７を円筒状基体１１にその端面開口から差込み、円筒状バネ体１７に加えられている力を解放することによって形成される。円筒状バネ体１７はその力の解放によりそのバネ性によって外側に向かって膨らみ、これによって、円筒状耐熱絶縁層体１３、円筒状発熱層体１４、円筒状耐熱絶縁層体１５、円筒状耐熱断熱層体１６が円筒状金属基体１１の内周面に圧接される。
【００２２】
この加熱ローラ１０によれば、円筒状発熱層体１４の熱が円筒状バネ体１７に伝わりにくくなるので、その立ち上がり時間を短縮することができる。
【００２３】
しかしながら、円筒状耐熱断熱層体１６それ自体が熱容量を有し、図６に示すように、この円筒状耐熱断熱層体１６の層厚を例えば２.５ｍｍにすると、立ち上がり時間T3が遅くなり、その層厚を例えば３ｍｍにすると、その立ち上がり時間T4は更に一層遅くなる。これに対して、円筒状耐熱断熱層体１６の層厚を例えば２ｍｍ、１ｍｍにした場合には、その立ち上がり時間T5、T6はほとんど変わらず、層厚２.５ｍｍの場合の立ち上がり時間T3に較べて早く、円筒状発熱層体を接着剤によって円筒状金属基体の内周面に固着する構成の加熱ローラの立ち上がり時間とほとんど遜色のない程度となり、従って、円筒状耐熱断熱層体１６の層厚は１ｍｍ乃至２ｍｍとするのが望ましい。
【００２４】
円筒状バネ体１７は加熱ローラ１０の回転に伴って軸方向（スラスト方向）にずれる可能性があり、これによって、円筒状バネ体１７が給電接触部１４aに接触して、電気回路がショートを起こす可能性がある。そこで、これを防止するために、図７に示すように、円筒状バネ体１７の両端に切片部１７aが設けられていると共に、円筒状耐熱絶縁層体１５、円筒状耐熱断熱層体１６の両端に切片部１５a、１６aが設けられている。切片部１７aは円筒状金属製基体１１の内周端面部まで延長され、その切片部１７aはスポット溶接、ハトメ、リベット締結等の固定手段によって円筒状金属基体１１の内周端面部に固定される。切片部１５a、１６aは切片部１７aが円筒状発熱層体１４の給電接触部１４aに接触するのを防止する役割を果たす。
【００２５】
これによって、円筒状バネ体１７のスラスト方向の移動が拘束され、加熱ローラ１０の回転中に円筒状バネ体１７が円筒状金属基体１１のスラスト方向に移動して発熱層体又は給電キャップ部材に接触してショートするという現象を防止できる。
【００２６】
この発明の実施の形態では、円筒状バネ体１７を長方形状SUS板を丸めることによって形成したが、円筒状バネ体１７としてコイルバネを用いても良い。このコイルバネには、その直径が円筒状金属基体１１の内径（円筒状発熱層体１４の内径）と同等程度の外径を有するものを用い、円筒状金属基体１１に差し込むときには、そのコイルバネをその延びる方向両端側を引っ張って、そのコイルバネを縮径させ、この状態で円筒状金属基体１１の内部に差し込んで、引張りを中止してコイルバネに加えていた力を解放する。これによって、コイルバネが元の状態に復元し、円筒状耐熱絶縁層体１３、円筒状発熱層体１４、円筒状耐熱絶縁層体１５、円筒状耐熱断熱層体１６が円筒状金属基体１１の内周面に圧接される。
【００２７】
【発明の効果】
本発明によれば、円筒状発熱層体と円筒状バネ体との間に円筒状断熱層体が設けられているので、円筒状発熱層体の熱が円筒状バネ体に伝わりにくくなり、もっぱら円筒状発熱層体の熱が円筒状金属基体の外周面に導かれるので、円筒状発熱層体を円筒状バネ体によって円筒状金属基体の内周面に圧接する構成の加熱ローラを有する定着装置であっても、その立ち上がり時間を短縮することができる。
また、加熱ローラの回転中に円筒状バネ体が円筒状金属基体のスラスト方向に移動して円筒状発熱層体又は給電キャップ部材に接触してショートするという現象を防止できる。
【図面の簡単な説明】
【図１】従来の加熱ローラの断面図である。
【図２】従来の加熱ローラの立ち上がり時間を説明するために用いたグラフ図である。
【図３】本発明に係わる加熱ローラの垂直方向断面図である。
【図４】図３に示す加熱ローラの水平方向断面図である。
【図５】図３に示す加熱ローラの製作過程を説明するための斜視図である。
【図６】本発明の加熱ローラの立ち上がり時間を説明するために用いたグラフ図である。
【図７】図３に示す加熱ローラの変形例を説明するための水平方向断面図である。
【符号の説明】
１０加熱ローラ
１１円筒状金属基体
１３円筒状絶縁層体
１４円筒状発熱層体
１５円筒状絶縁層体
１６円筒状断熱層体
１７円筒状バネ体[0001]
BACKGROUND OF THE INVENTION
In the present invention, a cylindrical heat generating layer body is provided on the inner peripheral surface of a cylindrical metal base (cylindrical metal core) via a cylindrical insulating layer body, and the cylindrical heat insulating layer body has a cylindrical insulating layer on the inner peripheral surface thereof. The present invention relates to a fixing device having a heating roller provided with a cylindrical spring body that presses a cylindrical heat generating layer body against a cylindrical metal substrate together with the cylindrical insulating layer body through a layer body.
[0002]
[Prior art]
Conventionally, as shown in FIG. 1, in a fixing device, a heating roller 1 for fixing an unfixed toner image on a recording sheet in cooperation with a pressure roller (not shown) is constituted by a cylindrical metal substrate 2. A cylindrical heat generating layer body 4 is provided on the inner peripheral surface of the cylindrical metal base 2 via a cylindrical insulating layer body 3. A cylindrical insulating layer body is provided on the inner peripheral surface of the cylindrical heat generating layer body 4. It is known that a cylindrical spring body 6 is provided through 5 and a release layer 7 is provided on the outer peripheral surface of the cylindrical metal base 2.
[0003]
The cylindrical heat generating layer body 4 is composed of a heat generating resistor pattern, for example. The energization structure to the cylindrical heat generating layer body 4 is as follows, for example.
[0004]
That is, the fixing device is provided with a non-conductive hollow resin brush holder. The cylindrical metal base 2 is provided with a power supply cap member at the side end opening. A slidable power supply brush is provided in the hollow resin brush holder. The power supply brush is pressed against the power supply cap member by a spring member, and is connected to a conductive wire disposed in the hollow resin brush holder. The power supply cap member is energized.
[0005]
[Problems to be solved by the invention]
However, in this conventional heating roller 1, the cylindrical spring body 6 is in contact with the inner peripheral surface side of the cylindrical heat generating layer body 4 via the insulating layer body 5. Escapes toward the cylindrical spring body 6 through the insulating layer body 5, and as a result, there is a problem that the rise time of the fixing device is slow.
[0006]
FIG. 2 shows a rise time of a heating roller having a configuration in which the cylindrical heat generating layer 4 is fixed to the inner peripheral surface of the cylindrical metal base 2 with an adhesive, and the cylindrical heat generating body 4 is connected to the cylindrical metal base by the cylindrical spring body 6. 2 is a graph comparing the rise time of the pressure roller 1 configured to be in pressure contact with the inner peripheral surface of a cylindrical metal. As shown in FIG. The rising time T1 until the outer peripheral surface of the pressure roller 1 configured to be in pressure contact with the inner peripheral surface of the substrate 2 reaches 180 ° C. is applied to the inner peripheral surface of the cylindrical metal substrate 2 with the cylindrical heating layer 4 by an adhesive. In the pressure roller 1 having a structure in which the conventional cylindrical heat generating layer body 4 is pressed against the inner peripheral surface of the cylindrical metal base 2 by the cylindrical spring body 6 later than the rising time T2 of the heating roller having a fixed structure, the rising is started. Takes too much time and power There is a problem of taking too much.
[0007]
The present invention has been made in view of the above circumstances, and an object of the present invention is to provide a fixing device having a heating roller having a configuration in which a cylindrical heating layer body is pressed against an inner peripheral surface of a cylindrical metal substrate by a cylindrical spring body. Even so, an object of the present invention is to provide a fixing device that can shorten the rise time.
[0008]
[Means for Solving the Problems]
The fixing device according to claim 1 further includes a heating roller that fixes an unfixed toner image on a recording sheet in cooperation with a pressure roller, and the heating roller includes a cylindrical metal base, and the cylindrical metal A cylindrical heat generating layer body is provided on the inner peripheral surface of the base via a cylindrical heat resistant insulating layer body, and a cylindrical spring body is provided on the inner peripheral surface of the cylindrical heat generating layer body via the cylindrical heat resistant insulating layer body. In the fixing device provided with
A cylindrical heat - insulating layer body is provided between the cylindrical heat - generating layer body and the cylindrical spring body, and the total axial length of the cylindrical heat-resistant insulating layer body in contact with the inner peripheral surface of the cylindrical metal base is the cylinder. Longer than the axial total length of the cylindrical heat generating layer body and shorter than the total axial length of the cylindrical metal substrate, and exists between the cylindrical heat generating layer body and the cylindrical heat generating layer body and the cylindrical spring body The overall length in the axial direction of the cylindrical heat-resistant insulating layer body is shorter than the overall length in the axial direction of the cylindrical spring body, and power supply contact portions are provided at both ends of the cylindrical heat generating layer body. A feeding cap member that is in contact with the feeding contact portion is provided at both ends, a section is provided at both ends of the cylindrical spring body, and the cylindrical heating layer body and the cylindrical spring body Between both ends of the cylindrical heat-resistant insulating layer and the cylindrical heat-resistant insulating layer A section is provided at the end, and the section of the cylindrical spring body is extended to the inner peripheral end surface of the cylindrical metal base and fixed to the inner peripheral end surface by a fixing means. The section portion and the section portion of the cylindrical heat insulating layer body are characterized in that the section portion of the cylindrical spring body is prevented from coming into contact with the feeding contact portion of the cylindrical heat generating layer body .
[0009]
According to the invention described in claim 1, since the cylindrical heat insulating layer body is provided between the cylindrical heat generating layer body and the cylindrical spring body, the heat of the cylindrical heat generating layer body is transferred to the cylindrical spring body. Since the heat of the cylindrical heating layer body is guided exclusively to the outer peripheral surface of the cylindrical metal substrate, the heating of the configuration in which the cylindrical heating layer body is pressed against the inner peripheral surface of the cylindrical metal substrate by the cylindrical spring body Even in a fixing device having a roller, the rise time can be shortened.
In addition, it is possible to prevent a phenomenon in which the cylindrical spring body moves in the thrust direction of the cylindrical metal base during rotation of the heating roller and contacts the cylindrical heating layer or the power supply cap member to cause a short circuit.
[0010]
The fixing device according to claim 2 is characterized in that the thickness of the cylindrical heat insulating layer is 2 mm or less.
[0011]
According to the second aspect of the present invention, the rise time of the fixing device can be efficiently advanced without increasing the material cost required for the cylindrical heat-insulating layer body more than necessary.
[0014]
DETAILED DESCRIPTION OF THE INVENTION
In FIG. 3, 10 is a heating roller. The heating roller 10 is composed of a cylindrical metal base 11. The cylindrical metal base 11 is formed using a metal material such as iron, aluminum, copper, and stainless steel.
[0015]
A release layer 12 is provided on the outer peripheral surface of the cylindrical metal substrate 11. The release layer 12 has a thickness of 10 μm to 30 μm, for example, and is formed by coating the outer peripheral surface of the cylindrical metal substrate 11 with a PFA or PTFE material.
[0016]
A cylindrical heat generating layer body 14 is provided on the inner peripheral surface of the cylindrical metal base 11 via a cylindrical heat-resistant insulating layer body 13. The cylindrical heat-resistant insulating layer 13 is made of a resin material such as polyimide. A cylindrical heat-resistant insulating layer body 15 is provided on the inner peripheral surface of the cylindrical heating layer body 14. The cylindrical heat generating layer body 14 is made of, for example, a metal foil (heat generating resistance pattern) such as stainless steel, and the layer thickness is, for example, 25 μm to 100 μm.
[0017]
The material of the cylindrical heat-resistant insulating layer 15 is the same as that of the cylindrical heat-resistant insulating layer 13, and the thickness of the cylindrical heat-resistant insulating layers 13 and 15 is, for example, 25 μm to 100 μm. These cylindrical heat-resistant insulating layer bodies 13 are formed by applying sheets or coatings on both sides of the cylindrical heat generating layer body 14.
[0018]
A cylindrical heat resistant heat insulating layer body 16 is provided on the inner peripheral surface of the cylindrical heat generating layer body 14 via a cylindrical heat resistant insulating layer body 15. The cylindrical heat-resistant and heat-insulating layer 16 is formed using a felt member made of a material that does not ignite even at a high temperature of about 500 ° C., for example, a material such as Nomex or SC paper. It is desirable that the thickness of the cylindrical heat-resistant and heat-insulating layer body 16 is 2 mm or less. The reason will be described later.
[0019]
A cylindrical spring body 17 is provided on the inner peripheral surface of the cylindrical heat-resistant and heat insulating layer body 16. The cylindrical heat-resistant insulating layer body 13, the cylindrical heat-generating layer body 14, the cylindrical heat-resistant insulating layer body 15, and the cylindrical heat-resistant and heat-insulating layer body 16 are pressed against the inner peripheral surface of the cylindrical metal substrate 11 by a cylindrical spring body 17. The The cylindrical spring body 17 is formed by rounding a rectangular SUS plate. The layer thickness of the cylindrical spring body 17 is, for example, 50 μm to 200 μm.
[0020]
As shown in FIG. 4, the axial total length of the cylindrical heat-resistant insulating layer 13 is longer than the total axial length of the cylindrical heat generating layer 14 and protrudes at least 2.5 mm or more from the end face of the cylindrical heat generating layer 14. ing. The total length in the axial direction of the cylindrical heat-resistant insulating layer body 16 and the total length in the axial direction of the cylindrical heat-resistant insulating layer body 15 are substantially the same and shorter than the total length in the axial direction of the cylindrical heat-generating layer body 14. Power supply contact portions 14a and 14a are provided at the portion. A power supply cap member (not shown) is fitted into the opening portions at both ends of the cylindrical metal base 11, and the power supply cap member is brought into contact with the power supply contact portions 14a and 14a. The power supply contact portions 14a and 14a have an axial width of, for example, 2 mm or more. The overall length in the axial direction of the cylindrical spring body 17 is shorter than the overall length in the axial direction of the cylindrical heat-resistant insulating layer 15, and the length from the end surface of the cylindrical spring body 17 to the end surface of the cylindrical heat-resistant insulating layer 15 is 2. It is desirable for insulation to be 5 mm or more.
[0021]
As shown in FIG. 5, the heating roller 10 includes a cylindrical heat-resistant insulating layer 13, a cylindrical heat-generating layer 14, a cylindrical heat-resistant insulating layer 15, and a cylindrical heat-resistant and heat-insulating material on the inner peripheral surface of a cylindrical metal base 11. After the layer body 16 is disposed, a cylindrical spring body 17 having a diameter smaller than the inner diameter of the cylindrical heat-resistant and heat-insulating layer body 16 is inserted into the cylindrical base body 11 through the opening of its end face, and is added to the cylindrical spring body 17. Formed by releasing the force. The cylindrical spring body 17 bulges outward due to its springiness by releasing its force, whereby the cylindrical heat-resistant insulating layer body 13, the cylindrical heat generating layer body 14, the cylindrical heat-resistant insulating layer body 15, and the cylindrical heat-resistant layer body. The heat insulating layer body 16 is pressed against the inner peripheral surface of the cylindrical metal base 11.
[0022]
According to the heating roller 10, the heat of the cylindrical heat generating layer body 14 is not easily transmitted to the cylindrical spring body 17, so that the rise time can be shortened.
[0023]
However, the cylindrical heat-resistant and heat-insulating layer body 16 itself has a heat capacity. As shown in FIG. 6, when the layer thickness of the cylindrical heat-resistant and heat-insulating layer body 16 is set to 2.5 mm, for example, the rise time T3 is delayed, When the layer thickness is 3 mm, for example, the rise time T4 is further delayed. On the other hand, when the layer thickness of the cylindrical heat-resistant heat insulation layer 16 is set to 2 mm or 1 mm, for example, the rising times T5 and T6 are hardly changed, and compared with the rising time T3 when the layer thickness is 2.5 mm. The rise time of the heating roller having a configuration in which the cylindrical heat generating layer body is fixed to the inner peripheral surface of the cylindrical metal base with an adhesive is almost inferior to that of the heating heat resistant layer body 16. Is preferably 1 mm to 2 mm.
[0024]
The cylindrical spring body 17 may be displaced in the axial direction (thrust direction) as the heating roller 10 rotates. As a result, the cylindrical spring body 17 comes into contact with the power supply contact portion 14a, and the electric circuit is short-circuited. There is a possibility of waking up. Therefore, in order to prevent this, as shown in FIG. 7, the end portions 17a are provided at both ends of the cylindrical spring body 17, and the cylindrical heat-resistant insulating layer body 15 and the cylindrical heat-resistant heat insulating layer body 16 are provided. Section portions 15a and 16a are provided at both ends. The section 17a is extended to the inner peripheral end face of the cylindrical metal base 11, and the section 17a is fixed to the inner peripheral end face of the cylindrical metal base 11 by fixing means such as spot welding, eyelet and rivet fastening. . The section portions 15a and 16a serve to prevent the section portion 17a from coming into contact with the power supply contact portion 14a of the cylindrical heat generating layer body 14.
[0025]
As a result, the movement of the cylindrical spring body 17 in the thrust direction is restrained, and the cylindrical spring body 17 moves in the thrust direction of the cylindrical metal base 11 during the rotation of the heating roller 10 to become a heat generating layer body or a power supply cap member. It is possible to prevent the phenomenon of short circuit due to contact.
[0026]
In the embodiment of the present invention, the cylindrical spring body 17 is formed by rounding a rectangular SUS plate, but a coil spring may be used as the cylindrical spring body 17. As this coil spring, one having an outer diameter approximately equal to the inner diameter of the cylindrical metal base 11 (inner diameter of the cylindrical heat generating layer body 14) is used. When the coil spring is inserted into the cylindrical metal base 11, the coil spring is The both ends of the extending direction are pulled to reduce the diameter of the coil spring, and in this state, the coil spring is inserted into the cylindrical metal base 11 to stop the tension and release the force applied to the coil spring. As a result, the coil spring is restored to its original state, and the cylindrical heat-resistant insulating layer body 13, the cylindrical heat-generating layer body 14, the cylindrical heat-resistant insulating layer body 15, and the cylindrical heat-resistant and heat-insulating layer body 16 are included in the cylindrical metal substrate 11. It is pressed against the peripheral surface.
[0027]
【The invention's effect】
According to the present invention, since the cylindrical heat-insulating layer body between the cylindrical heat generating layer body and the cylindrical spring member is provided, becomes the heat of the cylindrical heat generating layer body is hardly transmitted to the cylindrical spring member, exclusively Since the heat of the cylindrical heat generating layer body is guided to the outer peripheral surface of the cylindrical metal substrate, the fixing device has a heating roller configured to press the cylindrical heat generating layer body against the inner peripheral surface of the cylindrical metal substrate by the cylindrical spring body. Even so, the rise time can be shortened.
In addition, it is possible to prevent a phenomenon in which the cylindrical spring body moves in the thrust direction of the cylindrical metal base during rotation of the heating roller and contacts the cylindrical heating layer or the power supply cap member to cause a short circuit.
[Brief description of the drawings]
FIG. 1 is a cross-sectional view of a conventional heating roller.
FIG. 2 is a graph used for explaining a rise time of a conventional heating roller.
FIG. 3 is a vertical sectional view of a heating roller according to the present invention.
4 is a horizontal cross-sectional view of the heating roller shown in FIG. 3. FIG.
5 is a perspective view for explaining a manufacturing process of the heating roller shown in FIG. 3; FIG.
FIG. 6 is a graph used for explaining the rising time of the heating roller of the present invention.
7 is a horizontal sectional view for explaining a modification of the heating roller shown in FIG. 3. FIG.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 10 Heating roller 11 Cylindrical metal base 13 Cylindrical insulating layer body 14 Cylindrical heat generating layer body 15 Cylindrical insulating layer body 16 Cylindrical heat insulating layer body 17 Cylindrical spring body

Claims

A heating roller for fixing an unfixed toner image on the recording paper in cooperation with the pressure roller is provided. The heating roller is formed of a cylindrical metal base, and a cylindrical heat resistant material is formed on the inner peripheral surface of the cylindrical metal base. In a fixing device in which a cylindrical heating layer body is provided via an insulating layer body, and a cylindrical spring body is provided on the inner peripheral surface of the cylindrical heating layer body via a cylindrical heat - resistant insulating layer body,
A cylindrical heat - insulating layer body is provided between the cylindrical heat - generating layer body and the cylindrical spring body, and the total axial length of the cylindrical heat-resistant insulating layer body in contact with the inner peripheral surface of the cylindrical metal base is the cylinder. Longer than the axial total length of the cylindrical heat generating layer body and shorter than the total axial length of the cylindrical metal substrate, and exists between the cylindrical heat generating layer body and the cylindrical heat generating layer body and the cylindrical spring body The overall length in the axial direction of the cylindrical heat-resistant insulating layer body is shorter than the overall length in the axial direction of the cylindrical spring body, and power supply contact portions are provided at both ends of the cylindrical heat generating layer body. A feeding cap member that is in contact with the feeding contact portion is provided at both ends, a section is provided at both ends of the cylindrical spring body, and the cylindrical heating layer body and the cylindrical spring body Between both ends of the cylindrical heat-resistant insulating layer and the cylindrical heat-resistant insulating layer A section is provided at the end, and the section of the cylindrical spring body is extended to the inner peripheral end surface of the cylindrical metal base and fixed to the inner peripheral end surface by a fixing means. The fixing device is characterized in that the section portion and the section portion of the cylindrical heat insulating layer body prevent the section portion of the cylindrical spring body from coming into contact with the power supply contact portion of the cylindrical heating layer body .

The fixing device according to claim 1, wherein the heat insulating layer has a thickness of 2 mm or less.