JP6105128B1

JP6105128B1 - Pressure roller

Info

Publication number: JP6105128B1
Application number: JP2016100200A
Authority: JP
Inventors: 康嘉大庭; 大輔望月
Original assignee: Nissei Electric Co Ltd
Current assignee: Nissei Electric Co Ltd
Priority date: 2016-05-19
Filing date: 2016-05-19
Publication date: 2017-03-29
Anticipated expiration: 2036-05-19
Also published as: JP2017207643A

Abstract

【課題】加圧ローラの回転時に発生する応力集中による、弾性層自体の破壊を抑制する。【解決手段】芯金１の外周に設けた弾性層２において、弾性層２の芯金１近傍における許容伸び率が、弾性層２の外周近傍の許容伸び率よりも高くなるよう加圧ローラ４を構成し、加圧ローラ４と定着ベルトでニップ部を形成した定着装置において定着動作を行う際、加圧ローラ４の表面に定着ベルトとの接触による抵抗が発生した状態で、加圧ローラ４が回転する。この際、弾性層２に応力集中が発生し、この応力集中は弾性層２に伸びを発生させる力として作用することになる。【選択図】図２Disruption of an elastic layer itself due to stress concentration generated when a pressure roller rotates is suppressed. In an elastic layer provided on the outer periphery of a metal core, a pressure roller is set so that an allowable elongation ratio in the vicinity of the metal core of the elastic layer is higher than an allowable elongation ratio in the vicinity of the outer periphery of the elastic layer. When the fixing operation is performed in the fixing device in which the nip portion is formed by the pressure roller 4 and the fixing belt, the pressure roller 4 is in a state in which resistance is generated on the surface of the pressure roller 4 due to contact with the fixing belt. Rotates. At this time, stress concentration occurs in the elastic layer 2, and this stress concentration acts as a force for generating elongation in the elastic layer 2. [Selection] Figure 2

Description

本発明は、電子写真複写機、ファクシミリ、あるいはプリンタ等の画像形成装置において、転写紙などの転写材上に転写されたトナー画像を加熱により定着する定着部に用いられる加圧ローラに関する。 The present invention relates to a pressure roller used in a fixing unit that fixes a toner image transferred onto a transfer material such as transfer paper by heating in an image forming apparatus such as an electrophotographic copying machine, a facsimile, or a printer.

トナー像を定着する定着装置として、ヒータを内蔵した加熱ローラ（ヒートローラ）と定着ローラ、これらのローラに張架されるエンドレスの定着ベルト、及び加圧ローラからなるベルト定着方式の装置が、ウォーミングアップ時間の短縮、並びに省エネの観点から、盛んに使用されるようになって来ている。
さらに、動作速度の高速化への要求も以前にもまして、強くなってきている。
これらの要求に対応する為には、定着ベルトと加圧ローラとにより形成されるニップ部の幅を大きくすることが必要となる。 As a fixing device for fixing a toner image, a heating roller (heat roller) with a built-in heater and a fixing roller, an endless fixing belt stretched around these rollers, and a belt fixing type device including a pressure roller are warmed up. From the viewpoint of time saving and energy saving, it is actively used.
Furthermore, the demand for higher operating speed has become stronger than before.
In order to meet these requirements, it is necessary to increase the width of the nip portion formed by the fixing belt and the pressure roller.

通常、ニップ幅を大きくする方法として、加圧ローラを構成する弾性層の硬度を低くする方法が取られている。弾性層の硬度を低くするための方法としては、弾性層を低硬度の材料で形成する、弾性層をスポンジ状に形成するといった方法が知られている。 Usually, as a method of increasing the nip width, a method of reducing the hardness of the elastic layer constituting the pressure roller is taken. As a method for reducing the hardness of the elastic layer, a method is known in which the elastic layer is formed of a low-hardness material and the elastic layer is formed in a sponge shape.

弾性層をスポンジ状に形成する方法として、特許文献１、２に記載のものなどが知られている。
特許文献１では、芯金の外周に発泡性シリコーンゴム等の弾性体を単体で押出成型後、加硫・熱処理して発泡性シリコーンゴムを発泡させて発泡ゴム被覆層を形成する方法が開示されている。 As a method for forming the elastic layer in a sponge shape, those described in Patent Documents 1 and 2 are known.
Patent Document 1 discloses a method of forming a foamed rubber coating layer by extruding an elastic body such as foamable silicone rubber on the outer periphery of a core metal, and then foaming the foamable silicone rubber by vulcanization and heat treatment. ing.

特許文献２では、あらかじめ作成した発泡シリコーンゴムからなるチューブを芯金上に接着剤等を用いて被覆する方法が開示されている。 Patent Document 2 discloses a method of coating a tube made of foamed silicone rubber prepared in advance on a metal core using an adhesive or the like.

しかしながら、このようなスポンジ状の弾性層は、弾性材料が網目状に形成された構造であるため、強い力が作用した際に網目状構造が破壊されやすく、強度の面では好ましくない構造である。
特に、定着装置の動作時には、加圧ローラの表面に定着ベルトとの接触抵抗が発生した状態で加圧ローラが回転するため、加圧ローラの回転時には最も変形が起きやすく、かつ多数の空孔を有するスポンジ状弾性層に図１に示したような応力集中が発生し、その網目状構造が徐々に破壊されていき、最終的に弾性層自体が破壊されてしまう事態もある。この応力集中は加圧ローラの回転軸に近いほど大きくなるため、特に弾性層の芯金近傍で破壊が起きやすい。 However, such a sponge-like elastic layer has a structure in which an elastic material is formed in a mesh shape. Therefore, the network structure is easily broken when a strong force is applied, and is not preferable in terms of strength. .
In particular, during the operation of the fixing device, the pressure roller rotates while the contact resistance with the fixing belt is generated on the surface of the pressure roller. A stress concentration as shown in FIG. 1 occurs in the sponge-like elastic layer having, and the network structure is gradually destroyed, and eventually the elastic layer itself may be destroyed. Since this stress concentration becomes larger as it approaches the rotation axis of the pressure roller, the stress is likely to break particularly near the core of the elastic layer.

実開平２−１１９６６２号公報Japanese Utility Model Publication No. 2-11962 特開平８−２１１７７４号公報Japanese Patent Laid-Open No. 8-21774

本発明の課題は、加圧ローラの回転時に発生する応力集中による、弾性層の破壊を抑制することにある。 An object of the present invention is to suppress the destruction of the elastic layer due to stress concentration generated when the pressure roller rotates.

本発明者らは、弾性層の破壊を抑制する方法を鋭意検討した結果、加圧ローラの回転時に発生する応力集中によって弾性層に伸びが発生し、弾性層が許容できる範囲を越える伸びが発生した際に弾性層の破壊が進行することを突き止め、応力集中が強く発生する芯金近傍における弾性層の許容伸び率を弾性層の外周側より高くすることで、上記の課題を解決するに至った。 As a result of intensive studies on a method for suppressing the breakage of the elastic layer, the present inventors have caused an elongation in the elastic layer due to the stress concentration generated during the rotation of the pressure roller, resulting in an elongation exceeding the allowable range of the elastic layer. As a result, it is determined that the elastic layer breaks down and the allowable elongation of the elastic layer in the vicinity of the core where stress concentration is strong is higher than that of the outer peripheral side of the elastic layer. It was.

本発明は、定着装置に使用される、芯金の外周に弾性層を設けた加圧ローラであって、弾性層の芯金近傍における許容伸び率は、弾性層の外周近傍の許容伸び率よりも高いことを特徴とする。 The present invention is a pressure roller provided with an elastic layer on the outer periphery of a cored bar used in a fixing device, wherein the allowable elongation rate in the vicinity of the cored bar of the elastic layer is greater than the allowable elongation rate in the vicinity of the outer periphery of the elastic layer. It is also characterized by high.

本発明の具体的な構造の１つの例は、弾性層は少なくとも２層を有する複層構造となっており、芯金に接触する層の許容伸び率を最も高くするとともに、芯金に接触する層の表面に凸部が設けられている。 One example of a specific structure of the present invention is a multi-layer structure in which the elastic layer has at least two layers. The elastic layer has the highest allowable elongation of the layer in contact with the core metal and is in contact with the core metal. Protrusions are provided on the surface of the layer .

本発明の具体的な構造の他の例は、弾性層は、外周側から内周側に向かって許容伸び率が高くなるよう、厚さ方向に許容伸び率の傾斜が設けられている。 In another example of the specific structure of the present invention, the elastic layer is provided with a slope of the allowable elongation rate in the thickness direction so that the allowable elongation rate increases from the outer peripheral side toward the inner peripheral side.

上記の構成を採る本発明によれば、以下のような顕著な作用・効果が奏される。

（ａ）強い応力集中が発生する芯金近傍の弾性層の許容伸び率を大きくすることで、伸びに起因する弾性層の破壊が抑制される。

（ｂ）芯金近傍以外の弾性層は応力集中の発生が弱いため、許容伸び率が小さい構成を採用することができ、芯金近傍以外の弾性層を調整することで、所望する加圧ローラの性能が得られる。

（ｃ）芯金近傍の弾性層は、芯金上に別途作成した管状体を被覆するという形で設けることができ、管状体の表面に凸部を設けることにより、弾性層の破壊抑制効果を向上させることができる。
According to the present invention employing the above-described configuration, the following remarkable actions and effects can be achieved.

(A) By increasing the allowable elongation rate of the elastic layer in the vicinity of the metal core where strong stress concentration occurs, the elastic layer is prevented from being broken due to the elongation.

(B) Since an elastic layer other than the vicinity of the core metal is weak in stress concentration, a configuration with a small allowable elongation can be adopted, and a desired pressure roller can be obtained by adjusting the elastic layer other than the vicinity of the core metal. Performance is obtained.

(C) The elastic layer in the vicinity of the cored bar can be provided in the form of covering a tubular body separately prepared on the cored bar, and by providing a convex part on the surface of the tubular body, the effect of suppressing the destruction of the elastic layer can be obtained. Can be improved.

加圧ローラに発生する応力集中の概念図であるIt is a conceptual diagram of the stress concentration which generate | occur | produces in a pressure roller. 従来の加圧ローラの構成を示す縦断面図である。It is a longitudinal sectional view showing a configuration of a conventional pressure roller. 従来の加圧ローラの構成を示す横断面図である。It is a transverse sectional view showing a configuration of a conventional pressure roller. 最内周側弾性層に凸部を設けた、本発明の加圧ローラの横断面図である。It is a cross-sectional view of the pressure roller of the present invention in which a convex portion is provided on the innermost circumferential elastic layer. 好ましい凸部の設け方の一例である。It is an example of how to provide a preferable convex part. 好ましい凸部の設け方のその他の例であるIt is the other example of how to provide a preferable convex part. 凸部の幅と高さを示した図である。It is the figure which showed the width | variety and height of a convex part. 凸部の形状の例である。It is an example of the shape of a convex part. 本発明の加圧ローラのその他の変形例を示す横断面図である。It is a cross-sectional view showing another modification of the pressure roller of the present invention.

以下、本発明について図２〜４を参照しながら説明する。
図２及び図３では、本発明の基礎となる従来の加圧ローラ４の一例を示し、１は芯金、２は芯金１の外周に設けられた弾性層、３は弾性層２の外周に設けられた離型層である。
図２、３においては、弾性層２は内周側弾性層２ａと外周側弾性層２ｂの２層構造となっている。 It will be described below with reference to FIG. 2-4 for the present invention.
2 and 3 show an example of a conventional pressure roller 4 that is the basis of the present invention. Reference numeral 1 denotes a cored bar, 2 denotes an elastic layer provided on the outer periphery of the cored bar 1, and 3 denotes an outer periphery of the elastic layer 2. Is a release layer.
2 and 3, the elastic layer 2 has a two-layer structure of an inner peripheral elastic layer 2a and an outer peripheral elastic layer 2b.

本発明の最大の特徴は、芯金１上に設けた複層構造の弾性層２において、芯金１に接触する弾性層の許容伸び率を、他の弾性層の許容伸び率よりも高くし、芯金１に接触する弾性層の表面に凸部を設けたことである。 The greatest feature of the present invention, the elastic layer 2 of the multilayer structure provided on the metal core 1, the allowable elongation of the elastic layer in contact with the metal core 1, higher than the allowable elongation other resilient layer In addition , a convex portion is provided on the surface of the elastic layer in contact with the cored bar 1 .

本発明において、許容伸び率とは、所定の力で弾性層の試験片を伸ばした際に、試験片の元の長さに対して、試験片が破断することなく伸びることができる長さのことを指し、ゴム材料における破断伸びに相当する値である。 In the present invention, the allowable elongation is a length that allows the test piece to stretch without breaking with respect to the original length of the test piece when the elastic layer test piece is stretched with a predetermined force. This is a value corresponding to the elongation at break in the rubber material.

加圧ローラ４と定着ベルトでニップ部を形成した定着装置において定着動作を行う際、加圧ローラ４の表面に定着ベルトとの接触による抵抗が発生した状態で、加圧ローラ４が回転する。この際、弾性層２に応力集中が発生し、この応力集中は弾性層２に伸びを発生させる力として作用することになる。
この応力集中は芯金１に近づくほど、言い換えると、加圧ローラ４の回転軸からの半径方向の距離が短いほど大きくなる。この応力集中によって弾性層２が伸び、弾性層２が許容できる伸びを越えると、弾性層２の部分的な破壊が始まる。この破壊が進行すると。状況によっては弾性層２全体が破壊される事態に至ることもある。 When a fixing operation is performed in a fixing device in which a nip portion is formed by the pressure roller 4 and the fixing belt, the pressure roller 4 rotates in a state where resistance due to contact with the fixing belt is generated on the surface of the pressure roller 4. At this time, stress concentration occurs in the elastic layer 2, and this stress concentration acts as a force for generating elongation in the elastic layer 2.
This stress concentration increases as the distance from the cored bar 1 decreases, in other words, as the radial distance from the rotation axis of the pressure roller 4 decreases. When the elastic layer 2 expands due to this stress concentration and the elastic layer 2 exceeds the allowable elongation, partial destruction of the elastic layer 2 starts. As this destruction progresses. Depending on the situation, the entire elastic layer 2 may be destroyed.

このため、弾性層２の芯金１近傍における許容伸び率を、弾性層２の外周近傍の許容伸び率よりも高くすることで、弾性層２において最も破壊されやすい部分における応力集中への耐久性が高まり、結果として弾性層２の破壊を抑制することができる。 For this reason, by making the allowable elongation rate in the vicinity of the core metal 1 of the elastic layer 2 higher than the allowable elongation rate in the vicinity of the outer periphery of the elastic layer 2, durability against stress concentration in the portion most easily broken in the elastic layer 2. As a result, breakage of the elastic layer 2 can be suppressed.

弾性層２の外周近傍は、加圧ローラ４の使用に不都合が生じない範囲において、許容伸び率が小さい構成を採用することができるので、所望する加圧ローラ４の特性によって、弾性層２の外周近傍はその状態、特性を種々選択することができる。 In the vicinity of the outer periphery of the elastic layer 2, it is possible to adopt a configuration with a small allowable elongation within a range where there is no problem in using the pressure roller 4. Various states and characteristics can be selected in the vicinity of the outer periphery.

弾性層２の芯金１近傍における許容伸び率を、弾性層２の外周近傍の許容伸び率よりも高くする方法は複数存在するが、弾性層２を複層構造として、芯金１に接触する層の許容伸び率を最も高くするのが簡便な方法である。
図２及び３では、弾性層２を内周側弾性層２ａと外周側弾性層２ｂの２層構造とし、内周側弾性層２ａの許容伸び率を外周側弾性層２ｂよりも高くしている。 There are a plurality of methods for increasing the allowable elongation ratio in the vicinity of the core metal 1 of the elastic layer 2 to be higher than the allowable elongation ratio in the vicinity of the outer periphery of the elastic layer 2, but the elastic layer 2 has a multi-layer structure and contacts the core metal 1. A simple method is to make the allowable elongation of the layer the highest.
2 and 3, the elastic layer 2 has a two-layer structure of an inner peripheral elastic layer 2a and an outer peripheral elastic layer 2b, and the allowable elongation of the inner peripheral elastic layer 2a is higher than that of the outer peripheral elastic layer 2b. .

複層構造は２層構造に限定されるものではなく、所望する加圧ローラ４の特性によって、３層構造、４層構造・・・と、さらなる複層構造にしても良い。
３層以上の複層構造の場合も、芯金１に接触する層（最内周側弾性層）の許容伸び率が最も高くするよう構成する。
図２、３においては内周側弾性層２ａが最内周側弾性層２ａである。 The multilayer structure is not limited to the two-layer structure, but may be a three-layer structure, a four-layer structure, and so on, depending on the desired characteristics of the pressure roller 4.
Even in the case of a multi-layer structure of three or more layers, the allowable elongation percentage of the layer in contact with the cored bar 1 (the innermost elastic layer) is set to be the highest.
2 and 3, the inner circumferential elastic layer 2a is the innermost circumferential elastic layer 2a.

弾性層２を複層構造とする場合は、最内周側弾性層２ａをソリッド層、それ以外の層をスポンジ層とすることで、最内周側弾性層２ａの許容伸び率を最も高くすることができる。ソリッド層は材料が密に充填されているため、伸びが起きる前に破壊されてしまう網目状構造を有するスポンジ層より、高い許容伸び率を有する。
一方、スポンジ層はソリッド層より硬度を低く設定できるため、ニップ幅の確保に寄与できる。 When the elastic layer 2 has a multilayer structure, the innermost elastic layer 2a is a solid layer and the other layers are sponge layers, so that the allowable elongation of the innermost elastic layer 2a is maximized. be able to. Since the solid layer is closely packed with material, it has a higher allowable elongation than a sponge layer having a network structure that breaks before elongation occurs.
On the other hand, since the sponge layer can be set lower in hardness than the solid layer, it can contribute to securing the nip width.

弾性層２を複層構造とする際に、ソリッド層とスポンジ層の違いによって各層の許容伸び率を変化させる場合、同じ材料で許容伸び率を変化させることができる。
すなわち、各層を同じ材料で形成することができるので、各層間を接着、あるいは融着といった手段で固定する際に高い固定強度を得ることができ、この点においても最内周側弾性層２ａをソリッド層、それ以外の層をスポンジ層とする構造は好ましい構造である。 When the elastic layer 2 has a multilayer structure, when the allowable elongation of each layer is changed depending on the difference between the solid layer and the sponge layer, the allowable elongation can be changed with the same material.
That is, since each layer can be formed of the same material, it is possible to obtain a high fixing strength when fixing each layer by means such as adhesion or fusion. In this respect as well, the innermost circumferential elastic layer 2a is provided. A structure in which the solid layer and the other layers are sponge layers is a preferable structure.

弾性層２を複層構造とする際に、各層の許容伸び率を変化させる方法は、ソリッド層とスポンジ層の違いによって変化させる方法の他、材料選択によって変化させる方法、添加剤によって変化させる方法などを使用しても良い。 When the elastic layer 2 has a multi-layer structure, the method of changing the allowable elongation of each layer is not only the method of changing by the difference between the solid layer and the sponge layer, but also the method of changing by material selection, the method of changing by the additive Etc. may be used.

また、弾性層２を複層構造とする際は、最内周側弾性層２ａの肉厚を、弾性層２全体の肉厚の５０％未満とするのが好ましい。この構造にすることによって、弾性層２の外周側に位置する層の厚さが最内周側弾性層２ａの肉厚より厚くなり、加圧ローラ４の特性は、弾性層２の外周側に位置する層によって発現する特性が支配的になる。
最内周側弾性層２ａは、高い許容伸び率に基づく弾性層２の破壊抑制が主目的であるため、この目的に寄与しない特性は、加圧ローラ４の特性として発現しにくいように構成するのが好ましい。 Further, when the elastic layer 2 has a multilayer structure, it is preferable that the thickness of the innermost circumferential elastic layer 2 a is less than 50% of the total thickness of the elastic layer 2. By adopting this structure, the thickness of the layer located on the outer peripheral side of the elastic layer 2 becomes thicker than the thickness of the innermost peripheral elastic layer 2a, and the pressure roller 4 has a characteristic on the outer peripheral side of the elastic layer 2. The characteristic expressed by the layer located becomes dominant.
The innermost circumferential elastic layer 2 a is mainly configured to suppress the breakage of the elastic layer 2 based on a high allowable elongation, and therefore, characteristics that do not contribute to this purpose are configured to be difficult to be expressed as characteristics of the pressure roller 4. Is preferred.

具体的には、最内周側弾性層２ａの肉厚は０．１〜５ｍｍ、弾性層２を構成する最内周側弾性層２ａ以外の層の肉厚の合計を６ｍｍ以上とするのが好ましい。 Specifically, the innermost elastic layer 2a has a thickness of 0.1 to 5 mm, and the total thickness of the layers other than the innermost elastic layer 2a constituting the elastic layer 2 is 6 mm or more. preferable.

加えて、本発明では、図４に示したように、最内周側弾性層２ａの表面に凸部５を設ける。この構成により、最内周側弾性層２ａとこれに接触する層（図４においては外周側弾性層２ｂ）の境界における、応力集中への耐久性を高めることができる。 In addition, in the present invention, as shown in FIG. 4, Ru provided protrusions 5 on the surface of the innermost elastic layer 2a. With this configuration, it is possible to improve durability against stress concentration at the boundary between the innermost circumferential elastic layer 2a and the layer in contact with the innermost circumferential elastic layer 2a (outer circumferential elastic layer 2b in FIG. 4).

最内周側弾性層２ａと外周側弾性層２ｂの境界は、芯金１に近い距離にあり、最内周側弾性層２ａより小さいとは言え境界付近には加圧ローラ４の回転時に強い応力集中が発生し、許容伸び率が小さい外周側弾性層２ｂが破壊される恐れもある。
凸部５を設けることで、加圧ローラ４を製造した際に、凸部５に挟まれた隙間は外周側弾性層２ｂによって埋められ、最内周側弾性層２ａと外周側弾性層２ｂの境界は略凸凹状となる。
この凸凹状の境界においては、強い応力集中が発生した場合、応力によって凸部５が倒れるように変形する。凸部５は許容伸び率が高いため、変形が起きても破壊されることはなく、凸凹状の境界に発生する応力集中を分散させる機能を果たす。このため、外周側弾性層２ｂへの応力集中による負荷が減少し、結果として境界付近における外周側弾性層２ｂの破壊を抑制することができる。 The boundary between the innermost peripheral elastic layer 2a and the outer peripheral elastic layer 2b is at a distance close to the core metal 1 and is smaller than the innermost peripheral elastic layer 2a, but near the boundary is strong when the pressure roller 4 rotates. Stress concentration may occur, and the outer peripheral elastic layer 2b having a small allowable elongation rate may be broken.
By providing the convex portion 5, when the pressure roller 4 is manufactured, the gap sandwiched between the convex portions 5 is filled with the outer peripheral side elastic layer 2 b, and the innermost peripheral elastic layer 2 a and the outer peripheral side elastic layer 2 b The boundary is substantially uneven.
In the uneven boundary, when a strong stress concentration occurs, the convex portion 5 is deformed so as to fall down due to the stress. Since the convex portion 5 has a high allowable elongation rate, the convex portion 5 is not broken even if the deformation occurs, and functions to disperse the stress concentration generated at the irregular boundary. For this reason, the load by the stress concentration to the outer peripheral side elastic layer 2b decreases, and as a result, the destruction of the outer peripheral side elastic layer 2b near the boundary can be suppressed.

加えて、凸部５を設けることにより、定着動作時における加圧ローラ４の凹みが回復する速度を速める効果も存在する。
加圧ローラ４と定着ベルトでニップ部を形成する場合、定着ベルトと接触している部分の加圧ローラ４の表面は凹む一方、定着ベルトと接触していない部分の加圧ローラ４の表面は、加圧ローラ４の横断面図を見た時に元の円形になっているのが好ましい。
加圧ローラ４の表面が凹んだ際に、外周側弾性層２ｂの変形に伴って、最内周側弾性層２ａに設けた凸部５は倒れるように変形するが、加圧ローラ４の表面を凹ます力が無くなると、元の凸型に立ち上がろうとするため、この凸部５が立ち上がる力によって外周側弾性層２ｂの元の形状への回復が促進される。従って、凸部５の存在によって、加圧ローラ４の凹みが回復する速度が速まる。 In addition, providing the convex portion 5 also has an effect of increasing the speed at which the dent of the pressure roller 4 is recovered during the fixing operation.
When the nip portion is formed by the pressure roller 4 and the fixing belt, the surface of the pressure roller 4 that is in contact with the fixing belt is recessed, while the surface of the pressure roller 4 that is not in contact with the fixing belt is The original circular shape is preferable when the cross-sectional view of the pressure roller 4 is viewed.
When the surface of the pressure roller 4 is recessed, the convex portion 5 provided on the innermost peripheral elastic layer 2a is deformed so as to fall with the deformation of the outer peripheral elastic layer 2b. When the force that dents disappears, the original convex shape tends to rise, and the force by which the convex portion 5 rises promotes the recovery of the outer peripheral elastic layer 2b to the original shape. Therefore, the presence of the convex portion 5 increases the speed at which the depression of the pressure roller 4 recovers.

この凸部５による、加圧ローラ４の凹み回復速度の向上効果は、最内周側弾性層２ａがソリッド層、外周側弾性層２ｂがスポンジ層となっている時に、特に有効な効果である。
凸部５が立ち上がる速さは、最内周側弾性層２ａの反発弾性率が高いと速く、また、加圧ローラ４の凹み回復速度は外周側弾性層２ｂの反発弾性率が低いと遅くなる。
材料が同じ場合、ソリッド層は反発弾性率が高く、スポンジ層は反発弾性率が低くなるため、スポンジ層に起因する加圧ローラ４の凹み回復速度の遅さを、ソリッド層によって形成された凸部５が立ち上がる速さで補うことができ、スポンジ層を使用する場合の課題の一つである凹み回復速度の遅さを改善する効果が得られる。 The effect of improving the dent recovery speed of the pressure roller 4 by the convex portion 5 is a particularly effective effect when the innermost elastic layer 2a is a solid layer and the outer peripheral elastic layer 2b is a sponge layer. .
The speed at which the convex portion 5 rises is faster when the rebound resilience of the innermost peripheral elastic layer 2a is higher, and the dent recovery speed of the pressure roller 4 is slower when the rebound resilience of the outer peripheral elastic layer 2b is lower. .
When the material is the same, the solid layer has a high rebound resilience, and the sponge layer has a low rebound resilience, so that the depression recovery speed of the pressure roller 4 caused by the sponge layer is reduced. The speed at which the portion 5 rises can be compensated, and an effect of improving the slowness of the dent recovery speed, which is one of the problems when using the sponge layer, can be obtained.

弾性層２に発生する応力集中は、図１に示したように、主に加圧ローラ４の軸方向（長さ方向）に直交する方向に発生し、弾性層２の伸びもこの方向に発生するため、凸部５は加圧ローラ４の軸方向に直交しない方向に連続的に設けるのが好ましい。
一例としては、図５に示したような、加圧ローラ４の軸方向に沿って一直線状に延びた凸部５が、最内周側弾性層２ａの外周面に、円周方向に複数並ぶよう設けられた構成、すなわち、加圧ローラ４の横断面図を見た時に、最内周側弾性層２ａの外周が平歯車状の形状となるような構成が挙げられる。 As shown in FIG. 1, the stress concentration generated in the elastic layer 2 mainly occurs in a direction orthogonal to the axial direction (length direction) of the pressure roller 4, and the elongation of the elastic layer 2 also occurs in this direction. Therefore, it is preferable that the convex portion 5 is continuously provided in a direction not orthogonal to the axial direction of the pressure roller 4.
As an example, as shown in FIG. 5, a plurality of convex portions 5 extending in a straight line along the axial direction of the pressure roller 4 are arranged in the circumferential direction on the outer circumferential surface of the innermost circumferential elastic layer 2a. A configuration in which the outer periphery of the innermost elastic layer 2a has a spur gear shape when the cross-sectional view of the pressure roller 4 is viewed is exemplified.

このような、最内周側弾性層２ａの外周面に、円周方向に複数並ぶよう凸部５を設けた構成にすることで、最内周側弾性層２ａと外周側弾性層２ｂの境界付近において最内周側弾性層２ａと外周側弾性層２ｂが円周方向に交互に現れる。先述の通り、弾性層２に発生する応力集中は、主に加圧ローラ４の軸方向に直交する方向に発生するが、最内周側弾性層２ａと外周側弾性層２ｂが円周方向に交互に存在することにより、外周側弾性層２ｂのみでは吸収が困難な応力集中の一部が、許容伸び率が高い最内周側弾性層２ａが倒れるように変形することで吸収され、外周側弾性層２ｂに発生する応力集中が分散されることになり、結果として最内周側弾性層２ａと外周側弾性層２ｂの境界付近における外周側弾性層２ｂの破壊抑制効果を得ることができる。 The boundary between the innermost peripheral elastic layer 2a and the outer peripheral elastic layer 2b is obtained by providing a plurality of convex portions 5 arranged in the circumferential direction on the outer peripheral surface of the innermost peripheral elastic layer 2a. In the vicinity, the innermost elastic layer 2a and the outer elastic layer 2b appear alternately in the circumferential direction. As described above, the stress concentration generated in the elastic layer 2 is mainly generated in the direction orthogonal to the axial direction of the pressure roller 4, but the innermost circumferential elastic layer 2a and the outer circumferential elastic layer 2b are arranged in the circumferential direction. By being alternately present, a part of the stress concentration that is difficult to be absorbed only by the outer peripheral elastic layer 2b is absorbed by the innermost elastic layer 2a having a high allowable elongation being deformed so that the outer peripheral side The stress concentration generated in the elastic layer 2b is dispersed, and as a result, the effect of suppressing the destruction of the outer peripheral elastic layer 2b in the vicinity of the boundary between the innermost peripheral elastic layer 2a and the outer peripheral elastic layer 2b can be obtained.

図５では、凸部５は加圧ローラ４の軸方向に沿って一直線状に伸びているが、必ずしも加圧ローラ４の軸方向に沿う必要はなく、例えば図６に示したような、最内周側弾性層２ａの外周面に螺旋状に凸部５を設け、加圧ローラ４の軸方向に対して凸部５が斜めに設けられている構成などにしても良い。 In FIG. 5, the convex portion 5 extends in a straight line along the axial direction of the pressure roller 4, but does not necessarily need to be along the axial direction of the pressure roller 4, for example, as shown in FIG. A configuration in which the convex portion 5 is provided spirally on the outer peripheral surface of the inner peripheral elastic layer 2 a and the convex portion 5 is provided obliquely with respect to the axial direction of the pressure roller 4 may be employed.

図５に示すように、加圧ローラ４の軸方向に沿って一直線状に伸びた凸部５を、円周方向に複数並べる場合、凸部５の個数は３の倍数、もしくは４の倍数であることが好ましい。
凸部５の個数を３の倍数、もしくは４の倍数とすることで、凸部５を円周方向に均等に設けることが容易にでき、最内周側弾性層２ａに発生する応力集中を外周側弾性層２ｂへ均等に分散させることができる。 As shown in FIG. 5, when a plurality of convex portions 5 extending in a straight line along the axial direction of the pressure roller 4 are arranged in the circumferential direction, the number of the convex portions 5 is a multiple of 3 or a multiple of 4. Preferably there is.
By making the number of the convex portions 5 a multiple of 3 or a multiple of 4, the convex portions 5 can be easily provided in the circumferential direction, and the stress concentration generated in the innermost circumferential elastic layer 2a can be reduced to the outer circumference. It can be evenly dispersed in the side elastic layer 2b.

凸部５の個数の下限値は、総数を３の倍数とする時は３個、総数を４の倍数とする時は４個である。
凸部５の個数の上限値は、芯金１の外径ｄ［ｍｍ］に円周率πを乗じた値を、凸部５の幅ｗ［ｍｍ］で除した値である。
なお、凸部５の幅ｗは、凸部５の形状に関係なく、凸部５の最大幅を用い、通常は図７に示したように凸部５の底辺の長さを幅ｗとして扱う。 The lower limit of the number of the convex portions 5 is 3 when the total number is a multiple of 3, and 4 when the total number is a multiple of 4.
The upper limit value of the number of the convex portions 5 is a value obtained by dividing a value obtained by multiplying the outer diameter d [mm] of the core metal 1 by the circumferential ratio π by the width w [mm] of the convex portions 5.
Note that the width w of the convex portion 5 uses the maximum width of the convex portion 5 regardless of the shape of the convex portion 5, and normally treats the length of the base of the convex portion 5 as the width w as shown in FIG. .

凸部５の形状は所望する破壊抑制効果に応じて、図５、６に示した三角形状の他、図８（Ａ）に示したような半円状、図８（Ｂ）に示したような矩形状、図８（Ｃ）に示した矩形と半円を組み合わせた略楕円状などを適宜選択して使用すれば良い。 The shape of the convex portion 5 is a semicircular shape as shown in FIG. 8A, as shown in FIG. 8A, as shown in FIG. 8B, in addition to the triangular shape shown in FIGS. A rectangular shape, a substantially elliptical shape combining the rectangle shown in FIG. 8C and a semicircle, or the like may be appropriately selected and used.

凸部５を設ける際は、凸部５を除いた最内周側弾性層２ａの径を、最内周側弾性層２ａの外径、及び外周側弾性層２ｂの内径として扱い、各層の肉厚もこの径を基準に定義する。 When the convex portion 5 is provided, the diameter of the innermost peripheral elastic layer 2a excluding the convex portion 5 is treated as the outer diameter of the innermost peripheral elastic layer 2a and the inner diameter of the outer peripheral elastic layer 2b. Thickness is also defined based on this diameter.

凸部５を設ける際は、最内周側弾性層２ａの肉厚と凸部５の高さｈの合計を、弾性層２全体の肉厚の５０％未満とするのが好ましい。
この構造にすることによって、加圧ローラ４の特性は、弾性層２の外周側に位置する層によって発現する特性が支配的になる。 When providing the convex part 5, it is preferable that the sum of the thickness of the innermost circumferential elastic layer 2a and the height h of the convex part 5 is less than 50% of the total thickness of the elastic layer 2.
By adopting this structure, the characteristics of the pressure roller 4 are dominantly expressed by the layer located on the outer peripheral side of the elastic layer 2.

弾性層２を複層構造とする方法の１つとしては、芯金１が挿入された金型を直立させた状態で最内周側弾性層２ａとなる材料を注入し、所定の温度、時間で材料を硬化させ、芯金１の外周に所定の厚さ、高い許容伸び率を有する最内周側弾性層２ａとを形成した後、これを別の金型に挿入し、同様の作業で外周側弾性層２ｂを形成する方法が存在する。 One method of making the elastic layer 2 have a multilayer structure is to inject a material that will become the innermost elastic layer 2a in a state where the mold into which the core metal 1 is inserted is upright, and at a predetermined temperature and time. After the material is cured, the innermost elastic layer 2a having a predetermined thickness and a high allowable elongation is formed on the outer periphery of the core metal 1 and then inserted into another mold. There is a method of forming the outer peripheral elastic layer 2b.

弾性層２を複層構造とする他の方法の１つとしては、予め、最内周側弾性層２ａとなる材料で形成した管状体を準備し、芯金１にこの管状体を被覆したのち、管状体が被覆された芯金１を金型に挿入し、金型を直立させた状態で外周側弾性層２ｂとなる材料を注入し、外周側弾性層２ｂを形成する方法が存在する。 As another method of making the elastic layer 2 have a multilayer structure, a tubular body made of a material to be the innermost circumferential elastic layer 2a is prepared in advance, and the core metal 1 is coated with this tubular body. There is a method of forming the outer peripheral elastic layer 2b by inserting the core metal 1 covered with the tubular body into the metal mold and injecting a material to be the outer peripheral elastic layer 2b in a state where the mold is upright.

後者の方法は、管状体を押出成型して得ることができるため、製造効率の面で有利な方法である。押出成型では、外周面に凸部５を有する管状体も容易に得ることができるため、最内周側弾性層２ａに凸部５を設けるのに好ましい方法でもある。 The latter method is advantageous in terms of production efficiency because it can be obtained by extruding a tubular body. In the extrusion molding, there it is possible to easily obtain also tubular body having a protrusion 5 on the outer circumferential surface, also the preferred method for providing the protrusion 5 on the innermost circumference side elastic layer 2a.

芯金１の材料としては、アルミニウム、鉄など、本発明のような加圧ローラに広く使用されている芯金材料を適宜選択して使用すれば良い。 As a material of the core metal 1, a metal core material widely used for the pressure roller such as the present invention such as aluminum and iron may be appropriately selected and used.

弾性層２の材料としては、本発明のような加圧ローラに広く使用されているシリコーンゴムを適宜選択して使用すれば良い。
許容伸び率を高める際はソリッド状に形成し、硬度を下げる場合はスポンジ状に形成すれば良い。その他、材料グレードの変更や、添加剤により、所望する特性に調整すれば良い。 As a material for the elastic layer 2, silicone rubber widely used in the pressure roller as in the present invention may be appropriately selected and used.
When increasing the allowable elongation, it is formed in a solid form, and when reducing the hardness, it is formed in a sponge form. In addition, it may be adjusted to desired characteristics by changing the material grade or using additives.

弾性層２をスポンジ状に形成する方法は、（１）ミラブル型シリコーンゴムに加熱発泡剤を混合し、ゴムを架橋させる段階で発泡剤を分解ガス化させ、気泡を発生させてスポンジ化する方法、（２）中空フィラーを使用する方法、（３）水を含有する吸水性ポリマーを液状シリコーンゴムに混合し、水を蒸発させて空洞を形成する方法、（４）水と乳化剤を液状シリコーンゴムに混合し、ゴム中に水を分散させた後、水を蒸発させて空洞を形成する方法、など、従来知られているシリコーンゴムのスポンジ化方法を適宜選択して使用すれば良い。 The method for forming the elastic layer 2 in the form of a sponge is as follows: (1) A foaming agent is decomposed and gasified at the stage of mixing a heated foaming agent with millable silicone rubber and the rubber is cross-linked, and bubbles are generated to form a sponge. , (2) a method using a hollow filler, (3) a method in which a water-absorbing polymer containing water is mixed with a liquid silicone rubber and water is evaporated to form a cavity, and (4) a liquid silicone rubber containing water and an emulsifier. A conventionally known silicone rubber sponging method such as a method of forming a cavity by mixing water and dispersing water in the rubber and then evaporating the water may be used as appropriate.

本発明では必要に応じ、弾性層２の外周に離型層３を設けても良い。離型層３の材料は、フッ素樹脂、シリコーン樹脂など、離型層の材料として知られているものを適宜選択して使用すれば良い。離型層３の形成方法も、チューブ状に成形したものを弾性層２上に被覆する、あるいは液状にしたものを弾性層２上にコーティングするなど、離型層の形成方法として知られているものを適宜選択して使用すれば良い。
なお、図２、３、４、８は離型層３を設けた場合の図である。 In this invention, you may provide the release layer 3 in the outer periphery of the elastic layer 2 as needed. What is necessary is just to select and use suitably what is known as a material of a release layer, such as a fluororesin and a silicone resin, as the material of the release layer 3. FIG. The method for forming the release layer 3 is also known as a method for forming the release layer, such as coating the elastic layer 2 with a tube shape or coating the liquid layer with the liquid layer. What is necessary is just to select and use a thing suitably.
2, 3, 4, and 8 are diagrams when the release layer 3 is provided.

本発明においては、芯金１を含めた各層間の固定強度を上げるために、プライマー、ＲＴＶゴム接着剤等を適宜併用しても良い。 In the present invention, in order to increase the fixing strength between the layers including the core metal 1, a primer, an RTV rubber adhesive, or the like may be used in combination as appropriate.

以上、弾性層２を複層構造として芯金１に接触する層の許容伸び率を上げた場合について述べたが、その他の方法で芯金１近傍における弾性体の許容伸び率を上げても良く、図９に示すように、弾性層２の外周側から内周側に向かって許容伸び率が高くなるよう、スポンジの発泡状態を制御して、弾性層２の厚さ方向に許容伸び率の傾斜を設ける方法もある。 In the above, the case where the elastic layer 2 has a multi-layer structure and the allowable elongation of the layer in contact with the cored bar 1 is increased. However, the allowable elongation of the elastic body in the vicinity of the cored bar 1 may be increased by other methods. 9, the foaming state of the sponge is controlled so that the allowable elongation increases from the outer peripheral side to the inner peripheral side of the elastic layer 2, and the allowable elongation in the thickness direction of the elastic layer 2 is controlled. There is also a method of providing an inclination.

以下に、本発明を利用した加圧ローラの実施例について述べる。 Hereinafter, embodiments of the pressure roller using the present invention will be described.

［実施例１］
芯金１として、長さ２８０ｍｍ、外径１２ｍｍの鉄棒を使用する。 [Example 1]
As the metal core 1, an iron bar having a length of 280 mm and an outer diameter of 12 mm is used.

最内周側弾性層２ａとして、未加硫のシリコーンゴムに加硫剤、顔料を所定の量添加したシリコーンゴム材料をソリッド状の管状体に押出成形し、その後、所定の条件にて加熱・加硫して、長さ３５０ｍｍにカットしたものを準備する。 As the innermost elastic layer 2a, a silicone rubber material obtained by adding a predetermined amount of a vulcanizing agent and a pigment to unvulcanized silicone rubber is extruded into a solid tubular body, and then heated under predetermined conditions. Vulcanized and cut to 350 mm length.

最内周側弾性層２ａには内径φ１１．５ｍｍ、肉厚０．５ｍｍの管状体の表面に、幅１ｍｍ、高さ０．５ｍｍの矩形部と半径０．５ｍｍの半円部を組み合わせた、合計高さ１ｍｍの略楕円状の凸部５を設けた。
凸部５は加圧ローラの軸方向に沿って一直線状に伸びるように、最内周側弾性層２ａの円周方向に等間隔で設け、数は２４個とした。 In the innermost circumferential elastic layer 2a, a tubular body having an inner diameter of 11.5 mm and a thickness of 0.5 mm is combined with a rectangular portion having a width of 1 mm and a height of 0.5 mm and a semicircular portion having a radius of 0.5 mm. A substantially elliptical convex portion 5 having a total height of 1 mm was provided.
The convex portions 5 are provided at equal intervals in the circumferential direction of the innermost circumferential elastic layer 2a so as to extend in a straight line along the axial direction of the pressure roller, and the number is 24.

略楕円状の凸部５は、最内周側弾性層２ａとなるシリコーンゴム材料をソリッド状の管状体に押出成形する際に、対応する形状の金型を使用することにより、押出成型時に管状体と一体成型して設けた。 When the silicone rubber material to be the innermost peripheral elastic layer 2a is extruded into a solid tubular body, the substantially elliptical convex portion 5 is tubular at the time of extrusion molding by using a mold having a corresponding shape. It was provided as a single piece with the body.

芯金１上にＲＴＶゴム接着剤を塗布した後、作成した最内周側弾性層２ａを被覆し、所定の条件にて接着剤を加熱硬化させ、最内周側弾性層２ａの固定を完了した。 After the RTV rubber adhesive is applied on the cored bar 1, the innermost elastic layer 2a is coated and the adhesive is heated and cured under predetermined conditions to complete the fixing of the innermost elastic layer 2a. did.

最内周側弾性層２ａを固定した芯金１を金型に挿入し、金型を直立させた状態で外周側弾性層２ｂとなる材料を注入する。
外周側弾性層２ｂの材料には、第１の液状シリコーンベースポリマーに乳化剤、水、硬化触媒を添加した第１組成物に、第２の液状シリコーンベースポリマーに乳化剤、水、架橋剤を添加した第２組成物を配合し、攪拌脱泡させた配合材料を使用した。
配合材料を注入後、所定の条件にて加熱・加硫を行い、水を蒸発させて、スポンジ状の外周側弾性層２ｂを形成した。
外周側弾性層２ｂの外径はφ３２ｍｍ、硬度はＡＳＫＥＲ−Ｃ３２度に設定した。すなわち、外周側弾性層２ｂの肉厚は、計算上９．７ｍｍとなる。 The core metal 1 to which the innermost peripheral elastic layer 2a is fixed is inserted into a mold, and a material that becomes the outer peripheral elastic layer 2b is injected while the mold is upright.
In the material of the outer peripheral side elastic layer 2b, an emulsifier, water, and a crosslinking agent were added to the second liquid silicone base polymer in the first composition in which the emulsifier, water, and a curing catalyst were added to the first liquid silicone base polymer. The compounding material which mix | blended the 2nd composition and was made to deaerate by stirring was used.
After injecting the blended material, heating and vulcanization were performed under predetermined conditions to evaporate the water and form a sponge-like outer peripheral elastic layer 2b.
The outer diameter of the outer peripheral elastic layer 2b was set to 32 mm, and the hardness was set to 32 degrees ASKER-C. That is, the thickness of the outer peripheral elastic layer 2b is calculated to be 9.7 mm.

さらに、外周側弾性層２ｂ上にＲＴＶゴム接着剤を塗布し、離型層３として肉厚３０μｍの熱収縮性ＰＦＡチューブを被覆し、所定の条件にて加熱・収縮を行って離型層３の固定を完了し、本発明の加圧ローラを完成させた。 Further, an RTV rubber adhesive is applied on the outer peripheral elastic layer 2b, a heat-shrinkable PFA tube having a thickness of 30 μm is coated as the release layer 3, and the release layer 3 is heated and shrunk under predetermined conditions. And the pressure roller of the present invention was completed.

［実施例２］
芯金１、使用するシリコーンゴム、離型層３、製造方法は実施例１と同一のまま、最内周側弾性層２ａ、外周側弾性層２ｂの形状、寸法を以下のように変更した。 [Example 2]
The core metal 1, the silicone rubber to be used, the release layer 3, and the manufacturing method were the same as in Example 1, and the shapes and dimensions of the innermost peripheral elastic layer 2a and outer peripheral elastic layer 2b were changed as follows.

最内周側弾性層２ａは内径φ１１．５ｍｍ、肉厚０．３ｍｍの管状体の表面に、幅１．４ｍｍ、高さ０．７ｍｍの直角二等辺三角形状の凸部５を設けた形状とした。
凸部５は加圧ローラの軸方向に沿って一直線状に伸びるように、最内周側弾性層２ａの円周方向に等間隔で設け、数は８個とした。 The innermost circumferential elastic layer 2a has a shape in which a convex portion 5 having a right isosceles triangle shape having a width of 1.4 mm and a height of 0.7 mm is provided on the surface of a tubular body having an inner diameter of 11.5 mm and a thickness of 0.3 mm. did.
The convex portions 5 are provided at equal intervals in the circumferential direction of the innermost circumferential elastic layer 2a so as to extend in a straight line along the axial direction of the pressure roller, and the number thereof is eight.

外周側弾性層２ｂは実施例１と同じく、外径はφ３２ｍｍ、計算上の肉厚は９．７ｍｍとした。 As in Example 1, the outer peripheral elastic layer 2b had an outer diameter of 32 mm and a calculated thickness of 9.7 mm.

［比較例］
比較例として、実施例１の加圧ローラから最内周側弾性層２ａを割愛し、外径φ１２ｍｍの芯金１上に直接、外周側弾性層２ｂと同じ材料で構成された外径φ３２ｍｍ、肉厚１０ｍｍの弾性層を設けた以外は、実施例１と同様に作成した加圧ローラを準備した。すなわち、比較例の加圧ローラは芯金１の外周に許容伸び率が低いスポンジ状の弾性層が直接設けられた態様となる。 [Comparative example]
As a comparative example, omitting the innermost circumferential elastic layer 2a from the pressure roller of Example 1, the outer diameter φ32mm made of the same material as the outer circumferential elastic layer 2b directly on the core metal 1 having an outer diameter φ12mm, A pressure roller prepared in the same manner as in Example 1 was prepared except that an elastic layer having a thickness of 10 mm was provided. In other words, the pressure roller according to the comparative example has a mode in which a sponge-like elastic layer having a low allowable elongation is directly provided on the outer periphery of the cored bar 1.

以上のように作成した実施例１、２、及び比較例の加圧ローラの耐久試験を行った。耐久試験の方法は、加圧ローラを１９０℃に加熱し、表面に４２０Ｎの荷重を加えた状態で、１０秒間回転、２秒間回転停止を繰り返し、芯金１と接触する弾性層の内周面付近の時間経過に伴う変化を観察した。回転速度は周速２１０ｍｍ／秒に設定し、試験開始から３００時間まで観察を行った。 Durability tests of the pressure rollers of Examples 1 and 2 and the comparative example prepared as described above were performed. The durability test is performed by heating the pressure roller to 190 ° C. and applying a load of 420 N to the surface, repeatedly rotating for 10 seconds and stopping rotation for 2 seconds, and the inner peripheral surface of the elastic layer contacting the metal core 1 We observed changes with time. The rotation speed was set to a peripheral speed of 210 mm / sec, and observation was performed from the start of the test to 300 hours.

芯金１の外周に許容伸び率が低いスポンジ状の弾性層が直接設けられた比較例の加圧ローラについては、試験開始から７５時間経過後に、弾性層の内周面付近に亀裂が発生し、７９時間経過後には弾性層が芯金１から完全に浮いてしまい、加圧ローラとして十分に機能しなくなった。 For the pressure roller of the comparative example in which the sponge-like elastic layer having a low allowable elongation is directly provided on the outer periphery of the core metal 1, a crack occurs near the inner peripheral surface of the elastic layer after 75 hours from the start of the test. After 79 hours, the elastic layer was completely lifted from the core 1 and did not function sufficiently as a pressure roller.

芯金１の外周に、許容伸び率が高いソリッド状であり、略楕円状の凸部５を２４個備えた最内周側弾性層２ａを設けた実施例１の加圧ローラについては、試験開始から３００時間経過後も最内周側弾性層２ａの内周面付近には目立った変化がなく、許容伸び率が高い最内周側弾性層２ａ、及びその外周に凸部５を設けることで加圧ローラの耐久性が向上することが確認できた。 The pressure roller of Example 1 provided with the innermost peripheral elastic layer 2a which is a solid shape having a high allowable elongation on the outer periphery of the core metal 1 and includes 24 substantially elliptical convex portions 5 was tested. Even after 300 hours from the start, there is no noticeable change in the vicinity of the inner circumferential surface of the innermost circumferential elastic layer 2a, and the innermost circumferential elastic layer 2a having a high allowable elongation is provided, and the convex portion 5 is provided on the outer circumference. It was confirmed that the durability of the pressure roller was improved.

最内周側弾性層２ａの外周に直角二等辺三角形状の凸部５を８個設けた実施例２の加圧ローラについては、試験開始から２０５時間経過後に、最内周側弾性層２ａの内周面付近に亀裂が発生したが、その後は目立った変化がないまま３００時間が経過した。 For the pressure roller of Example 2 provided with eight right-angled isosceles triangular protrusions 5 on the outer periphery of the innermost peripheral elastic layer 2a, 205 hours after the start of the test, the innermost elastic layer 2a Although cracks occurred in the vicinity of the inner peripheral surface, 300 hours passed without noticeable change thereafter.

実施例２は実施例１と比較して耐久性は劣ると言えるが、凸部５を設けることによる耐久性の向上効果は得られているとともに、加圧ローラとしての機能は充分に維持された。
実施例２の加圧ローラは凸部５の数が少ない分、実施例１より耐久性は劣るが、凸部５間の間隔が広くなるため、外周側弾性層２ｂとなる材料を注入する際、実施例１よりも容易に凸部５の間へ材料を充填でき、製作容易性を維持しつつ耐久性を高めることができる点において優れた態様である。 Although it can be said that Example 2 is inferior in durability compared with Example 1, the effect of improving the durability by providing the convex portion 5 was obtained, and the function as a pressure roller was sufficiently maintained. .
The pressure roller of Example 2 is inferior in durability to Example 1 because the number of convex portions 5 is small, but the interval between the convex portions 5 is widened, so when injecting a material that becomes the outer peripheral elastic layer 2b. This is an excellent aspect in that the material can be filled between the convex portions 5 more easily than Example 1, and durability can be enhanced while maintaining ease of manufacture.

本発明の加圧ローラは、定着装置の加圧ローラとしてだけでなく、定着ローラ、プリンタのローラなど、各種印刷機器のローラとして好適に適用できる。 The pressure roller of the present invention can be suitably applied not only as a pressure roller of a fixing device but also as a roller of various printing devices such as a fixing roller and a printer roller.

１芯金
２弾性層
２ａ内周側弾性層（最内周側弾性層）
２ｂ外周側弾性層
３離型層
４加圧ローラ
５凸部
６気泡 1 Core 2 Elastic layer 2a Inner circumferential elastic layer (innermost circumferential elastic layer)
2b Outer peripheral elastic layer 3 Release layer 4 Pressure roller 5 Convex part 6 Bubble

Claims

A pressure roller provided with an elastic layer on an outer periphery of a core metal, the elastic layer having a multilayer structure having at least two layers, and an innermost elastic layer being a layer in contact with the core metal However, the pressure roller is characterized in that the allowable elongation is higher than that of the other layers, and a convex portion is provided on the surface of the innermost elastic layer .

The pressure roller according to claim 1, wherein the innermost elastic layer is a solid layer and the other layers are sponge layers.

The pressure roller according to claim 1 or 2, wherein a thickness of the innermost elastic layer is less than 50% of a thickness of the entire elastic layer.

The pressure roller according to claim 1, wherein the convex portion is continuously provided in a direction not orthogonal to the axial direction of the pressure roller.

The pressure roller according to claim 4, wherein the convex portion is continuously provided in a direction parallel to the axial direction of the pressure roller.

The pressure roller according to claim 5, wherein a plurality of the convex portions are provided in parallel on the surface of the innermost elastic layer.

The pressure roller according to claim 6, wherein the number of the convex portions is a multiple of 3 or 4.

8. The additive according to claim 6, wherein the number of the convex portions is equal to or less than a value obtained by dividing the outer diameter of the core metal by the circumferential ratio and the width of the convex portion. Pressure roller.

9. The total thickness of the innermost elastic layer and the height of the convex portion is less than 50% of the total thickness of the elastic layer 2, wherein the total thickness is 10%. The pressure roller described in 1.

In the multilayered elastic layer, the innermost circumferential elastic layer is formed by covering a tubular body made of an elastic material on a cored bar. The pressure roller according to any one of the above.

A pressure roller provided with an elastic layer on the outer periphery of a cored bar, wherein the allowable elongation in the vicinity of the cored bar of the elastic layer is higher than the allowable elongation in the vicinity of the outer periphery of the elastic layer. The pressure roller is provided with an inclination of the allowable elongation rate in the thickness direction so that the allowable elongation rate increases from the outer peripheral side toward the inner peripheral side.

The pressure roller according to any one of claims 1 to 11, wherein a release layer is provided on an outer periphery of the elastic layer.