JP3679224B2 - Isolated nails - Google Patents

Description

【００４０】
（式中、Ｘは直結または炭素数１〜１０の２価の炭化水素基、六フッ素化されたイソプロピリデン基、カルボニル基、チオ基、エーテル基およびスルホン基からなる群より選ばれた基を表わし、Ｒ₁ 〜Ｒ₄ は水素、炭素数１〜６の低級アルキル基、炭素数１〜６の低級アルコキシ基、塩素または臭素を表わし、互いに同じであっても異なっていてもよい。Ｙは炭素数２〜２７であり、脂肪族基、環式脂肪族基、単環式芳香族基、縮合多環式芳香族基、芳香族基が直接または架橋員により相互に連結された非縮合多環式芳香族基からなる群から選ばれた少なくとも一つの４価の基を表わす。）
さらに、上記式１中のＹの具体例を示せば下記の化２に示される４価の基である。
【００４１】
【化２】

【００４２】
この発明に用いる熱可塑性ポリイミド樹脂は、ジアミン成分として下記の化３で示されるエーテルジアミンと一種以上のテトラカルボン酸二無水物とを反応させて得られるポリアミド酸を脱水環化して得られる。
【００４３】
【化３】

【００４４】
化３で示されるエーテルジアミンにおいて、Ｒ₁ 〜Ｒ₄ が全て水素原子である典型例として、三井東圧化学社から「ＡＵＲＡＭ」の商標で市販されている熱可塑性ポリイミド樹脂がある。その製造方法は、特開昭６１−１４３４７８号公報、特開昭６２−６８８１７号公報、特開昭６２−８６０２１号公報に開示されている。
【００４５】
この熱可塑性ポリイミド樹脂は、ポリイミド樹脂固有の耐熱性を保ちながら熱可塑性を示すので、圧縮成形、射出成形または押出成形その他の溶融成形方法によって比較的容易に成形することができる。
【００４６】
また、前記化３の式で示されるジアミンの具体例として、以下に示すものが挙げられる。すなわち、ビス〔４−（３−アミノフェノキシ）フェニル〕メタン、１，１−ビス〔４−（３−アミノフェノキシ）フェニル〕エタン、１，２−ビス〔４−（３−アミノフェノキシ）フェニル〕エタン、２，２−ビス〔４−（３−アミノフェノキシ）フェニル〕プロパン、２−〔４−（３−アミノフェノキシ）フェニル〕−２−〔４−（３−アミノフェノキシ）−３−メチルフェニル〕プロパン、２，２−ビス〔４−（３−アミノフェノキシ）−３−メチルフェニル〕プロパン、２−〔４−（３−アミノフェノキシ）フェニル〕−２−〔４−（３−アミノフェノキシ）−３，５−ジメチルフェニル〕プロパン、２，２−ビス〔４−（３−アミノフェノキシ）−３，５−ジメチルフェニル〕プロパン、２，２−ビス〔４−（３−アミノフェノキシ）フェニル〕ブタン、２，２−ビス〔４−（３−アミノフェノキシ）フェニル−１，１，１，３，３，３−ヘキサフルオロプロパン、４，４´−ビス（３−アミノフェノキシ）ビフェニル、４，４´−ビス（３−アミノフェノキシ）−３−メチルビフェニル、４，４´−ビス（３−アミノフェノキシ）−３，３´−ジメチルビフェニル、４，４´−ビス（３−アミノフェノキシ）−３，５−ジメチルビフェニル、４，４´−ビス（３−アミノフェノキシ）−３，３´，５，５´テトラメチルビフェニル、ビス〔４−（３−アミノフェノキシ）フェニル〕ケトン、ビス〔４−（３−アミノフェノキシ）フェニル〕スルフィド、ビス〔４−（３−アミノフェノキシ）フェニル〕スルホン等が挙げられ、これらは単独または二種以上混合して用いることができる。
【００４７】
また、上記した熱可塑性ポリイミド樹脂の溶融流動性をそこなわない範囲で他のジアミンを混合して用いることもできる。混合して用いることとのできるジアミンとしては、たとえば、ｍ−アミノベンジルアミン、ｐ−アミノベンジルアミン、３，３´−ジアミノジフェニルエーテル、３，４´−ジアミノジフェニルエーテル、４，４´−ジアミノジフェニルエーテル、３，３´−ジアミノジフェニルスルフィド、３，４´−ジアミノジフェニルスルフィド、４，４´−ジアミノジフェニルスルフィド、３，３´−ジアミノジフェニルスルホン、３，４´−ジアミノジフェニルスルホン、４，４´−ジアミノジフェニルスルホン、３，３´−ジアミノベンゾフェノン、３，４´−ジアミノベンゾフェノン、４，４´−ジアミノベンゾフェノン、１，３−ビス（３−アミノフェノキシ）ベンゼン、１，３−ビス（４−アミノフェノキシ）ベンゼン、１，４−ビス（３−アミノフェノキシ）ベンゼン、１，４−ビス（４−アミノフェノキシ）ベンゼン、２，２−ビス〔４−（４−アミノフェノキシ）フェニル〕プロパン、４，４´−ビス（４−アミノフェノキシ）ビフェニル、４，４´−ビス（４−アミノフェノキシ）ケトン、ビス〔４−（４−アミノフェノキシ）フェニル〕スルフィド、ビス〔４−（４−アミノフェノキシ）フェニル〕スルホン等が挙げられ、これらのジアミンは通常３０モル％以下好ましくは５モル％以下混合して用いることができる。
【００４８】
なお、この発明で特に好ましく用いられる熱可塑性ポリイミド樹脂は、前記したジアミンとテトラカルボン酸二無水物とを有機溶媒中で反応させ、得られたポリアミド酸を脱水閉環して得られ、この方法で用いられるテトラカルボン酸二無水物は、下記の化４の式（式中Ｙは前記した化４の場合と同じ）で示される。
【００４９】
【化４】

【００５０】
化４の式で表わされるテトラカルボン酸二無水物の具体例としては、たとえば、エチレンテトラカルボン酸二無水物、１，２，３，４−ブタンテトラカルボン酸二無水物、シクロペンタンカルボン酸二無水物、ピロメリット酸二無水物、３，３´，４，４´−ベンゾフェノンテトラカルボン酸二無水物、２，２´，３，３´−ベンゾフェノンテトラカルボン酸二無水物、３，３´，４，４´−ビフェニルテトラカルボン酸二無水物、２，２´，３，３´−ビフェニルテトラカルボン酸二無水物、ビス（３，４−ジカルボキシフェニル）エーテル二無水物、ビス（３，４−ジカルボキシフェニル）スルホン二無水物、１，１−ビス（２，３−ジカルボキシフェニル）エタン二無水物、ビス（２，３−ジカルボキシフェニル）メタン二無水物、ビス（３，４−ジカルボキシフェニル）メタン二無水物、２，３，６，７−ナフタレンテトラカルボン酸二無水物、１，４，５，８−ナフタレンテトラカルボン酸二無水物、１，２，５，６−ナフタレンテトラカルボン酸二無水物、１，２，３，４−ベンゼンテトラカルボン酸二無水物、３，４，９，１０−ベリレンテトラカルボン酸二無水物、２，３，６，７−アントラセンテトラカルボン酸二無水物、１，２，７，８−フェナントレンテトラカルボン酸二無水物、４，４´−（ｐ−フェニレンジオキシ）ジフタル酸二無水物、４，４´−（ｍ−フェニレンジオキシ）ジフタル酸二無水物等が挙げられる。そして、これらテトラカルボン酸二無水物は単独または２種以上混合して用いる。
【００５１】
また、上述のポリイミド樹脂を製造するに際して、無水フタル酸などの芳香族ジカルボン酸無水物類やアニリンなどの芳香族モノアミン類を共存下に反応させて分子末端を封止したポリイミド樹脂であっても使用できる。
【００５２】
このような熱可塑性ポリイミド樹脂のなかでも、最も好ましいポリイミド樹脂は前記の化１で表わされる一般式中、（ａ）Ｘが直結、（ｂ）Ｙが単環式芳香族環、（ｃ）Ｒ₁ 〜Ｒ₂ は全て水素原子であるという条件ａ〜ｃのうち、少なくとも一以上、好ましくは全ての条件を満足するものであり、上記Ｘ、Ｙ、Ｒ₁ 〜Ｒ₄ を全て満足するポリイミド成分が、重合体全体のうち５０重量％以上、好ましくは７０重量％以上、より好ましくは８０〜１００重量％を含む熱可塑性ポリイミド樹脂であれば耐熱性を有し、また射出成形可能な溶融粘度となり、分離爪先端Ｒを精度よく射出成形できる。このような熱可塑性ポリイミド樹脂としては、三井東圧化学社製：オーラムを挙げることができる。
【００５３】
この発明において合成樹脂を補強する繊維状強化材としては、ｐＨが９以下、好ましくはｐＨ４〜９、より好ましくはｐＨ５〜８のウィスカを使用する。ウィスカは、針状（髭状）の単結晶体または多結晶体であり、結晶体の大きさは、平均直径０．０１〜１０μｍであり、一般的には平均繊維径が０．１〜５０μｍ、平均繊維長が１〜３００μｍの短繊維であり、これらは分離爪の先端部を良好に補強する。また、より好ましい繊維寸法は、平均繊維径が０．１〜１μｍ、平均繊維長が１〜１００μｍである。このようなウィスカのアスペクト比は、１〜２００、一般的には１０〜１００である。
【００５４】
このようなウィスカは、溶融混合して成形工程中に折れたりして最終的に成形体内に含まれているウィスカの平均繊維長は、約１０μｍ以下、好ましくは１μｍ以上未満となるものと考えられる。
【００５５】
ウィスカのｐＨを９以下に限定する理由は、ｐＨ９を越えるアルカリ性または極端な酸性を示すウィスカでは、ポリイミド樹脂のイミド結合またはエーテル結合等に関わる結合基を破壊することがあり、そのためにポリイミド樹脂の物性や寸法精度を低下させるからである。また、所定のｐＨ値の範囲外のウィスカが分離爪基材の表面に露出していると、その表面に被覆するプライマー樹脂層への悪影響も予想される。
【００５６】
ｐＨ９以下の酸性側のウィスカの具体例としては、ルチル型白色針状結晶体のような一般式ＴｉＯ₂ で示される酸化チタンウィスカ（ｐＨ６〜８）、９Ａｌ₂ Ｏ₃ ・２Ｂ₂ Ｏ₃ 、２Ａｌ₂ Ｏ₃ ・Ｂ₂ Ｏ₃ 等で示される白色針状結晶体のホウ酸アルミニウムウィスカ（ｐＨ７〜８）などがあり、またこれらにＳ（イオウ）を添加して白色化したものや、Ｐｂ、Ｃｄなどの不純物を含んで黄色や灰色のテトラポット状、またはこれらが折れて円錐状、テーパ状となったような一般式ＺｎＯで示される酸化亜鉛ウィスカ（ｐＨ７）も挙げられる。また、Ｋ₂ Ｏ・６ＴｉＯ₂ 、Ｋ₂ Ｏ・６ＴｉＯ₂ ・１／２Ｈ₂ Ｏや、Ｋ₂ Ｔｉ₂ Ｏ₅ 、Ｋ₂ Ｔｉ₄ Ｏ₉ 、Ｋ₂ Ｔｉ₆ Ｏ₁₃、Ｋ₂ Ｔｉ₈ Ｏ₁₇などのように一般式Ｋ₂ Ｏ・ｎＴｉＯ₂ （ｎは１以上の整数または２以上の偶数）で表わされるチタン酸カリウムウィスカ（ｐＨ７〜９）も挙げられる。
【００５７】
上述のウィスカ類は、所定の範囲内で非常に小径であり、かつ短繊維であるため、これらを含む耐熱性樹脂材を射出成形することによって、寸法精度がよく、かつ補強された先端Ｒ形状を有する分離爪を製造できる。しかし、前述のウィスカ類の平均直径や平均長さが所定の範囲より小さいものでは補強効果がなく、平均直径や平均長さが所定範囲を越えて大きいものでは分離爪の精密なＲ形状を形成することは困難である。
【００５８】
また、ウィスカとポリイミド樹脂などの分離爪を形成する合成樹脂とのぬれ性や結合性を改善するために、ウィスカ表面をアミノシラン系、エポキシシラン系などのカップリング剤を用いて表面処理を施すことが好ましい。
【００５９】
上記ウィスカのような繊維状強化材の配合割合は、合成樹脂中に１〜５０重量％であることが好ましい。なぜなら、前記の所定量未満の配合割合では、適当な補強効果がなく、所定割合を越えて配合すると、射出成形による成形性が悪くなるからである。また、その他の要因として、射出成形のショートショットなどの不具合の発生原因になり、分離爪の先端部のＲ形状を精度よく形成することが困難になる。このような傾向から、ウィスカ等の繊維状強化材のより配合割合は５〜５０重量％、さらに好ましくは１０〜４０重量％、特に好ましくは１０〜３０重量％である。
【００６０】
ここで、熱可塑性ポリイミド樹脂（ＴＰＩ）、ウィスカなどの混合手段は、これらを個別に溶融混合機に供給してもよいが、これらを予めヘンシェルミキサー、タンブラーミキサー、リボンブレンダーなど汎用の混合機で乾式混合した後、溶融混合機に供給してもよく、その具体的方法は特に限定されるものではない。
【００６１】
なお、この発明の効果を損なわない範囲内で、すなわち精密な分離爪の先端Ｒ形状を維持しつつ、分離爪全体の強度を向上できるならば、前記以外の針状繊維系補強材（例えば、ガラス繊維、炭素繊維、グラファイト繊維、セラミック繊維、ロックウール、スラグウール、シリコンカーバイドウィスカ、サファイアウィスカ、ウォラストナイト、鋼線、銅線、ステンレス鋼線、炭化ケイ素繊維）を添加してもよく、さらに酸化防止剤、熱安定剤、紫外線吸収剤、滑剤、離型剤、着色剤、難燃剤、帯電防止剤、結晶化促進剤などを適宜添加してもよい。これらの充填材についても、前記したｐＨ値と同様なｐＨ値のものを採用することは、樹脂材に悪影響を及ぼさないことからで好ましい。
【００６２】
そして、以上述べたようにして混合した成形材料は、約３９０〜４５０℃の温度範囲に加熱し可塑化した後、１５０〜２５０℃に加熱された金型中に充填し、１０００〜２０００ｋｇｆ／ｃｍ² の成形圧力で固化および離型することにより目的の分離爪を得る。
【００６３】
前記高温に加熱する理由は、所定のポリイミド樹脂の融点がおよそ３８８℃、測定条件などにより約３８０〜４００℃程度と高温であるためである。さらに、分離爪に所定の熱処理を施すことにより、耐熱変形性、寸法安定性、耐摩耗性に優れた長寿命の複写機用分離爪とすることもできる。
【００６４】
熱処理は、例えば、所定のポリイミド樹脂のガラス転移点（例えば２５０℃）以上で処理することが好ましく、約２５０〜３４０℃、好ましくは約２７０〜３３０℃の範囲で行われることが必要である。なぜならば、約３４０℃を越える温度では、分離爪に著しい熱変形が生じ実用上好ましくなく、一方、約２５０℃未満の温度では、耐熱変形性の向上は得られないからである。
【００６５】
熱処理時間は、加熱する温度により大きく変化するが、少なくとも２分以上、場合によっては数週間必要となる。すなわち、この発明によると、熱処理することによる分離爪の耐熱変形性の向上とその密度変化とは一定の法則があり、成形材料中のポリイミド成分の密度が少なくとも１．５％以上の密度増加をするに足りる時間を熱処理時間とすればよい。ここで、ポリイミド成分の密度増加率は、熱処理前後の分離爪の密度をＡＳＴＭ−Ｄ７９２に従い測定し、成形材料中の各成分の配合比および密度から計算で求めることができる。
【００６６】
したがって、熱処理時間については、約２７０℃加熱条件で約１２時間以上、約２８０℃加熱条件で約１時間以上、約３００℃加熱条件で約１０分以上、約３３０℃加熱条件で約２分以上、約３４０℃加熱条件で約１０分以上が必要であり、約３３０℃加熱条件にて所要時間が最小となることが判明している。
【００６７】
また、約２６０℃以下の加熱処理の場合、数週間以上の時間を必要とし、逆に約３４０℃以上の加熱処理の場合は、分離爪に著しい変形を生じさせるので、いずれの場合も実用的でない。熱処理時間は、後述のフッ素被膜の焼成時間と同程度であれば良く、例えば１〜１０時間程度であれば良い。
【００６８】
このような分離爪の熱処理は、分離爪を所定温度に制御された加熱装置の中で実施されるが、その加熱装置の形式には特に制限がない。しかし、通常は電気加熱方式によるものが便利であり、装置内の雰囲気としては、たとえば熱風循環式や熱風流通式などを利用することができる。
【００６９】
上記のような熱処理を施すことにより、分離爪基材の耐熱性が向上し、次に説明するフッ素系樹脂を主成分とする被膜をフッ素系樹脂の融点以上の温度で分離爪基材の表面に焼付け被覆することが可能になる。
【００７０】
以上のようにして分離爪の基材を形成した後、分離爪の少なくとも刃先表面に、パーフルオロアルキルビニルエーテル共重合体（以下、ＰＦＡと略記する。）を主成分とする非粘着性被膜を形成するが、ＰＦＡは分離爪基材との密着性に乏しいので、プライマーを介在させる必要がある。
【００７１】
このプライマー層は、平均粒径０．１〜１０μｍのテトラフルオロエチレン−ヘキサフルオロプロピレン共重合体（以下、ＦＥＰと略記する。）と、平均粒径０．３〜５μｍのポリアミドイミド樹脂、ポリイミド樹脂およびその先駆体（前駆体とも呼ばれる。）からなる群から選ばれる少なくとも一種とを含有するプライマーが挙げられる。プライマー層は、溶剤に前記成分を溶解または分散させたプライマー液を分離爪の表面に塗布し、溶剤を乾燥させたものからなる。
【００７２】
因みに、プライマーに用いられるＦＥＰ、非粘着性のフッ素樹脂被膜を形成するＰＦＡ、およびＰＴＦＥの物性は以下の通りである。
【００７３】
ＦＥＰの結晶融点は、２５３〜２８２℃、ＰＦＡの結晶融点は、３０２〜３１０℃、ＰＴＦＥの結晶融点は、３２７℃以上である。
【００７４】
ＦＥＰ、ＰＦＡおよびＰＴＦＥは、いずれもパーフルオロ系フッ素樹脂であり、分子構造の骨格である炭素原子の周囲が完全にフッ素原子または微量の酸素原子で取り囲まれており、強固なＣ−Ｆ結合によって耐熱性、耐薬品性、非粘着性、低摩擦係数等の諸特性に優れている点で好ましいものである。このようなフッ素樹脂のうち、ＰＦＡ、ＦＥＰの溶融粘度は、例えばＡＳＴＭ−Ｄ３３０７の評価方法による比溶融粘度でみると、３８０℃でそれぞれ１０⁴ 〜１０⁵ ポイズ、４×１０⁴ 〜１×１０⁵ ポイズであり、融点以上の温度で容易に溶融し基材に融着可能である。
【００７５】
上記のＦＥＰは、トリフルオロメチル基（−ＣＦ₃ ）を側鎖に有し、ＰＦＡはエーテル側鎖やパーフルオロアルコキシ側鎖（Ｃ_n Ｆ_2n+1）を有する鎖状フッ素樹脂であって、単独重合体であるＰＴＦＥとパーフルオロアルコキシ基またはヘキサフルオロプロピル基を含有する単量体との変性物や、ＰＴＦＥと上記側鎖を与えるコモノマーとを必須成分とする共重合体である。
【００７６】
このようなＰＦＡやＦＥＰは、ＡＳＴＭ−Ｄ３３０７の評価方法により、３７０〜３８０℃、詳しくは３７２±１℃における比溶融粘度が１×１０³ 〜１×１０⁶ ポイズである。また、メルトフローインデックス（メルトフローレートに同じ）は０．８〜３６ｇ／１０分、好ましくは０．８〜１８ｇ／１０分、またＦＥＰでは０．８〜１２ｇ／１０分、ヘキサフルオロプロピレンの含有量により４〜１２ｇ／１０分（ＡＳＴＭ−Ｄ３３０７）であるものが好ましいが、このような評価内容に特定されるものでなくてもよい。
【００７７】
なお、アルキル基の炭素数は、１〜１０または１〜４程度であり、各々がメチル基、エチル基、プロピル基、ブチル基等の状態になっていてもよく、アルキル基部分は、上記各々の基の数が少なくとも一種類以上で、単独または各々０．１〜１０重量％、好ましくは１〜８重量％、また３〜６重量％の割合、またはＦＥＰのヘキサフルオロプロピレン部分は８〜１６重量％、好ましくは８〜１０重量％の割合でそれぞれ含有されていれば適当な溶融粘度のものとなり、造膜成形性に優れており、しかも耐熱性に優れた被膜を分離爪表面に形成できる。
【００７８】
前記したようにＦＥＰを平均粒径０．１〜１０μｍとしたのは、プライマー層をできる限り薄膜化させて均一な膜厚を形成するためである。平均粒径が１０μｍを越える大きさでは均一な膜厚が形成できなくなる。
【００７９】
プライマーのＦＥＰ成分を結着するバインダー成分である平均粒径０．３〜５μｍのポリアミドイミド樹脂、ポリイミド樹脂およびその先駆体について、以下に説明する。
【００８０】
ポリアミドイミド樹脂は、分子構造中にアミド結合とイミド結合の両方を有する特徴があり、例えばアミド基を有する芳香族ジアミンとピロメリット酸などの芳香族４価カルボン酸との反応、無水トリメリット酸などの芳香族３価カルボン酸と、４，４´−ジアミノジフェニルエーテルなどのジアミンとの反応、芳香族イミド環を有する２塩基酸とジアミンとの反応などにより製造される。
【００８１】
具体的な化学構造は下記の化５に示すものが代表例として挙げられる。
【００８２】
【化５】

【００８３】
（式中、ｎは整数を表わし、Ｒ₇ は水素原子、メチル基、またはフェニル基を表わし、Ｒ₅ は少なくとも１つのベンゼン環を含む３価の芳香族基を表わし、Ｒ₆ は２価の有機基を表わす。）
なお、化５式中のＲ₅ の具体例を下記の化６に示した。
【００８４】
【化６】

【００８５】
また、前記した化５中のＲ₆ の具体例は、−（ＣＨ₂ ）_m − （式中、ｍは４〜１２の整数を表わす。）で示す飽和脂肪族炭化水素基や下記の化７の式に示したアリール基が挙げられる。
【００８６】
【化７】

【００８７】
以上説明したようなポリアミドイミド樹脂の具体例としては、下記の化８〜１１に示す樹脂または下記の化１１に示す米国アモコ社製：ＡＩなどを挙げることができる。
【００８８】
【化８】

【００８９】
【化９】

【００９０】
【化１０】

【００９１】
【化１１】

【００９２】
ポリイミド樹脂は、前述の分離爪の基材について詳細に記載したものも含め、例えば芳香族４価カルボン酸無水物（無水ピロメリット酸など）と芳香族ジアミン（ジアミノジフェニルエーテルなど）の反応で得られるイミド結合を分子内に有する高分子重合体である。
【００９３】
ポリイミド樹脂の具体例を下記の化１２の式で示した。
【００９４】
【化１２】

【００９５】
これらのポリイミド樹脂の市販品としては、下記の化１３の式で表わされるデュポン社製：ＲＹＲＥ−ＭＬ、ＰＹＲＡＬＩＮなどが挙げられる。
【００９６】
【化１３】

【００９７】
そして、これらの先駆体とは、低分子量であって、加熱により縮重合して高分子量のポリアミドイミド樹脂、またはポリイミド樹脂などのバインダー用重合体を生成するものをいう。
【００９８】
前記したように、ポリアミドイミド樹脂、ポリイミド樹脂またはそれらの先駆体のバインダー用重合体の大きさについて、平均粒径０．３〜５μｍに限定する理由は、プライマー層を可能な限り薄膜化し、しかも均一な膜厚にするためである。平均粒径が５μｍを越える大径では、均一な膜厚でプライマー層を形成できない。
【００９９】
ＦＥＰと、上述のバインダ用重合体との配合比は、ＦＥＰ１００重量部に対して、バインダ用重合体は、８０〜６００重量部である。このような配合比にすることにより、プライマー層が分離爪基材と非粘着性被膜とを強固に結合できる。バインダ用重合体の配合比が、このような所定範囲外ではプライマー層による分離爪基材と非粘着性被膜との密着強度が所期程度に至らない。
【０１００】
前述のようにプライマーは、バインダ用重合体を純水などの水や、溶剤類に分散または溶解してプライマー液として用いるが、その際の溶剤類としては、メチルエチルケトンなどのケトン類、メチルグリコールアセテート、２−ニトロプロパン、エチレングリコールアセテート、クレシル酸、キシレン類、トルエン類などの芳香族炭化水素類、Ｎ，Ｎ−ジメチルホルムアミド、Ｎ，Ｎ−ジメチルアセトアミド、Ｎ−メチル−２−ピロリドン（ＮＭＰ）などの非プロトン系極性溶剤類などが挙げられる。なお、混合溶剤であってもよいのは勿論である。
【０１０１】
溶剤の配合割合は、溶液１００重量％中に、ＮＭＰなどの非プロトン系極性溶媒類が、５〜４０重量％、好ましくは１０〜３０重量％、キシレンなどの芳香族炭化水素類の溶剤が１〜２０重量％、好ましくは３〜１０重量％、残部が純水などの水類であれば、この溶液中の樹脂固形分は、沈殿して固化し難く、また塗布前に適宜攪拌すれば、前記樹脂固形分は溶液中に適度に分散されるために好ましいと考えられる。
【０１０２】
プライマー液中のＦＥＰおよびバインダ用重合体からなる固形成分は、溶剤１００重量部に対して５〜１００重量部であり、好ましくは１０〜３０重量部である。固形成分が５重量部未満の少量では、分離爪表面にプライマー層が連続して充分に形成されず、１００重量部を越える多量では、スプレーガンなどの霧化装置のノズルが詰まること等により塗布作業の効率が低下し、またプライマー層が必要以上に厚膜になって分離爪の精密な先端形状を形成できない場合もある。
【０１０３】
以上の条件を全て満足する市販のプライマー液として、ダイキン工業社製のポリフロンＴＦＥエナメルを採用することができる。
【０１０４】
次に、フッ素樹脂を主成分とする非粘着性の被膜について説明する。
この被膜は、ＰＦＡ１００％でもよいが、ＰＴＦＥを１重量％以上３０重量％まで添加して耐摩耗性を向上させた複合被膜であってもよい。ただし、ＰＴＦＥの含有量が３０重量％を越える被膜では、被膜が不均一な膜厚になって好ましくない。
【０１０５】
このような非粘着性の被膜をプライマーを介して分離爪基材に被覆する場合には、前述のプライマーの使用状態と同様に溶剤に溶解または分散させて液状化する。その際の溶剤と固形成分の配合割合は、前記したプライマー液と同様であり、ここでは説明を省略する。
【０１０６】
プライマー液および非粘着性被膜についてのコーティング（塗布工程）時の温度は常温が好ましい。常温であればコーティング液は適当な粘度になって液だれの発生を防ぐことができるからである。
因みに、フォードカップ＃での粘度計測法は、カップ内の１００ｍｌの塗料が内径０．１６２インチ（０．４１１ｃｍ）のオリフィスを通って流出する時間を計測することにより粘度を評価する。
【０１０７】
被覆方法は、例えば吹き付け等の霧化塗布法（スプレーコーティング）、浸漬法（ディッピング）等を採用できる。霧化方法は、塗布液が微妙な粒子となって被塗物に付着するので塗膜の厚みを精度よく形成することができる。浸漬法では塗布液の歩留りを向上でき、塗布液を無駄にしないので好ましい。
【０１０８】
この発明では、分離爪先端部分の寸法精度を良好にするために、被膜を精度よく形成できる霧化塗布法により形成することが適当である。この時の霧化吐出圧は、２〜６ｋｇｆ／ｃｍ² 、好ましくは３〜５ｋｇｆ／ｃｍ² である。吐出圧が低すぎると霧状の粒子が粗くなり、高すぎると塗布液が多く飛散して無駄になりやすく、却って被膜も形成しがたいからである。
【０１０９】
上述のようにして、分離爪にプライマー液を塗布した後、例えば雰囲気温度８０〜１２０℃で１０〜３０分、乾燥炉でプライマー液の溶剤分を蒸発させ、次いで非粘着性被膜の分散液を塗布する。そして、分離爪を最高保持温度３４０〜３８０℃で焼成して、分離爪に非粘着性の被膜を均一かつ強固に密着させる。
【０１１０】
焼成工程では、所定の温度に達するまでに、例えば常温、８０℃、１３０℃、１８０℃、２３０℃、２８０℃という段階的な昇温を行ない、すなわち、１５〜１８０分の範囲内で１５〜６０分毎に徐々に昇温することにより、バインダー樹脂のキュアが徐々にかつ確実に進行し、均一な密着強度を有する被膜を形成することができる。
【０１１１】
また、１００〜１２０℃の昇温時には、１５〜６０分間定温で保持すれば、予備乾燥後の樹脂被膜内にごく僅かの水分や溶剤が含まれていたとしても、それを完全に乾燥させ、次段階の焼成を行なうことができる。
【０１１２】
このように段階的に昇温させた後の最高保持温度は、フッ素樹脂の融点より約３０〜７０℃高くなる温度であり、１５〜６０分、好ましくは３０分程度焼成すれば良好なものが得られる。保持時間がそれより短時間であれば、バインダー樹脂へのキュアが不安定となり、また長時間であれば「ソリ」の発生が懸念され、生産性および品質が共に不良となる。前記各温度段階を含めた加熱時間（全工程の合計）は、例えば２〜２４時間、好ましくは３〜１５時間の範囲に調整すればよい。
【０１１３】
因みに、短時間で急激に加熱して被膜を焼成しようとすると、前記の水分その他の溶剤が沸点を越えて気化し、被膜に泡状の膨れや穴（いわゆる「はじき」、「へこみ」、「わき」、「われ」、「ふくれ」）が発生する場合もある。
【０１１４】
焼成工程後の冷却は、前記した段階的な昇温とは逆の過程で段階的に冷却するか、または６０〜１８０分程度の時間をかけて連続的に徐冷してもよい。このように冷却すれば、被膜と被覆物とが互いに緊密に密着し、かつ寸法精度の高い分離爪を製造できる。
【０１１５】
焼成温度を３４０〜３８０℃に限定する理由は、３４０℃未満の低温ではＦＥＰ含有のプライマー層と非粘着性の被膜が薄膜化されず、特に非粘着性の被膜のＰＦＡが完全に溶融しないので、連続した被膜が形成され難くなるためである。また、３８０℃を越える高温の焼成温度は、分離爪基材の物性値が低下したり、分解がおこるなど熱的悪影響の弊害が起こるからである。
【０１１６】
プライマー層のＦＥＰの融点（２７０℃）は、非粘着性の被膜成分であるＰＦＡの融点（３１０℃）より約４０℃低い。この融点の差によって、プライマー層が接着強度を保ちながら５μｍ以下の薄膜になり得たと考えられる。
【０１１７】
このように、プライマー層の膜厚が均一になることにより、フッ素樹脂被膜を形成した分離爪先端Ｒもバラツキが少なく安定した形状になる。そのため、射出成形直後の分離爪の先端Ｒを一定に整えるための膜厚管理が可能となり、６０〜７５μｍの薄紙を良好に分離できる分離爪になる。
【０１１８】
このような分離爪の先端Ｒは、複写用紙の厚みの２／５〜４／５になるように設定する。具体的には、複写用紙の厚みが６０〜７５μｍであることを考慮すると、分離爪の先端Ｒは３０〜６５μｍ、好ましくは３０〜６０μｍである。
【０１１９】
分離爪の先端Ｒが、用紙等のシート部材よりも大きい場合にはシート部材を良好に剥離し難くなり、紙詰まり（ジャム）の原因になる。また、前記先端Ｒが所定範囲より小さければ、分離爪の取扱い時に先端部分の欠損発生の原因になる場合があると共に、そのような先端Ｒとするためには製造工程で精密切削加工等の加工が必要になって効率的に製造できなくなり、さらには精密な先端Ｒ形状の精度を管理する（品質維持の）ために多大な時間を要し、製造コストの低減を図り得なくなる。
【０１２０】
ここで、非粘着性被膜の焼成後の膜厚は５〜３０μｍが好ましい。なぜなら、５μｍ以下の薄膜では耐摩耗性が劣り、３０μｍを越える厚膜では分離爪の先端Ｒ（曲率半径）が１０〜６０μｍよりも大きくなる可能性がある。
【０１２１】
このような樹脂被膜の表面は、水、酢酸の水滴の接触角を測定することにより、表面の非粘着性を判断することができる。例えば水滴の接触角は、８０〜１２０°であれば、この発明において充分な非粘着性を有する樹脂被膜の表面状態であるとみなされ、より好ましい接触角は９０〜１２０°、特に通紙試験前では１００〜１２０°である。
【０１２２】
因みに、接触角の測定方法は、エルマ光学社製のゴニオメーター式接触角試験機を用い、常温、常圧で０．０１〜０．１ミリリットルの液滴、好ましくは０．０５ミリリットルの水滴を試験片の表面に滴下し、滴下直後から１分間（３０秒後および１分後）の接触角を測定する方法が代表的であるが、このような測定方法に限定されるものではない。
【０１２３】
また、この発明における図１〜４に示した分離爪の先端部近傍の角度は、特に限定されるものではなく、この発明の分離爪の先端部分の具体的な角度を例示すれば、４５°以下、好ましくは３０°以下であり、また下限が５〜１０°以上の鋭利な角度である。前記角度が所定範囲を越える鈍い角度では、分離爪に最も必要な用紙等のシート部材をローラから剥離する機能が損なわれる。前記角度が所定範囲未満の鋭角では、分離爪の先端部周辺の肉厚が薄くなり過ぎて用紙が分離爪の先端に引っ掛かるようになり、紙詰まりが発生したり、先端端部周辺に強度を越える過剰な力が作用するなどの弊害が発生する。
【０１２４】
なお、分離爪の刃先幅（板材の厚み）は、０．５〜５ｍｍ、好ましくは１〜３ｍｍであれば、爪先端の実用強度を保有し、しかも対接する相手ローラ表面の損傷を最低限に抑えられると考えられる。
【０１２５】
また、分離爪は、その表面に通紙面および分離爪を支持する軸または軸穴が形成されているが、これらはいずれも他部品と摺接する面であるから、これらの表面形状や表面粗さは小さいほうがよい。同様に、射出成形金型の分離爪キャビティ部の表面粗さは小さいほうが離型性のために良い。
【０１２６】
このような表面形状・表面粗さは、Ｒｍａｘ（最大粗さ）、Ｒａ（算術平均粗さ）、Ｒｚ（十点平均粗さ）等のＪＩＳで定義の評価法によって測定されるが、Ｒｍａｘで０．１〜２５μｍの範囲に形成する。０．１μｍ未満のＲｍａｘでは、精密な切削加工を要して製造効率が極端に低下するために好ましくなく、２５μｍを越えるＲｍａｘでは、摺動時の表面に傷が多く付くようになり、摩耗の一因にもなる。
【０１２７】
表面粗さは、表面に塗布された被膜表面の形状が下地の形状に影響されることにも影響があり、プライマーの表面が滑らかであれば、非粘着性被膜の表面も滑らかになる。なお、射出成形金型の分離爪キャビティ部の表面粗さが、２５μｍを越えると離型性が低下して歩留りおよび製造効率が低下して実用性を失することになる。このような傾向から、より好ましいＲｍａｘは１〜１０μｍであり、さらに好ましくは１〜３．２μｍである。
【０１２８】
上記したような表面形状・表面粗さは、この発明においてフッ素系樹脂が被覆された分離爪の通紙面の部分にも同様に要求される。なお、分離爪の仕様や使用条件によって、分離爪を支持する軸または軸穴が摩耗し難い場合には、前記した各々の表面粗さをＲｍａｘで３〜８μｍ程度の範囲にしてもよい。そして、表面粗さは、塗布被膜の表面も前記同様の範囲（例えばＲmax.で０．１〜２５μｍ）の表面粗さであれば、トナーの付着量をより少なくできると考えられる。
【０１２９】
この発明における分離爪の用途は、特に限定されたものではなく、例えば外部から与えられた電気信号によって記録パターンを感光体などの媒体上に形成し、この媒体上に形成された電気量のパターンを可視的なパターンに変換する種々の方式を採用したプリンタにも適用できることは勿論である。そのようなプリンタの方式としては、電子写真方式、感熱方式、光プリンタ方式、電子記録方式などが挙げられるが、この発明における分離爪の用途としては、電子写真装置が好適である。
【０１３０】
電子写真方式の種類としては、カールソン法、光・電荷注入法、光分極法、光起電力法、電荷移動法、電解電子写真法、静電潜像写真法、光電気泳動法、サーモプラスチック法が挙げられる。また、光プリンタとしては、レーザプリンタ、ＬＥＤ（発光ダイオード）プリンタ、液晶シャッタプリンタ、ＣＲＴプリンタが挙げられる。また、電子記録方式としては、静電記録方式、通電記録方式、電解記録方式、放電記録方式が挙げられ、更に直接法、間接法がある。また、これらの静電記録方法で油などを塗布する湿式または乾式などの方式がある。
【０１３１】
上記の方式が採用される具体的な装置としては、トナー像転写式の湿式静電複写機、乾式静電複写機（ＰＰＣ）、レーザービームプリンタ（ＬＢＰ）、液晶シャッタ（ＬＣＤ）プリンタ、ファクシミリ用プリンタ、発光ダイオード（ＬＥＤ）、銀塩写真方式によるプリンタ（ＣＲＴ）、印刷機その他周知の画像形成装置である。
【０１３２】
また、この発明の分離爪の装置に対する装着部位としては、感光部、現像部、定着部などであって、特に限定されないが、特に所定のフッ素系樹脂の優れた耐熱性を適用するならば、感光部や現像部よりも高温条件で使用される定着部に適用できる。すなわち、この発明の分離爪は、定着装置内に配置される定着ローラや加圧ローラなどの定着部に用いることが適当であり、好ましくは用紙のトナーの付着面と対面するローラ、すなわち定着ローラ用分離爪、なかでもトナー付着性に対する厳しい要求のある乾式静電複写装置の定着ローラ用分離爪に好適である。そして、この分離爪は、相手ローラを損傷しない程度の静荷重、例えば１〜３０ｇｆの接触圧にて接する。
【０１３３】
【実施例】
実施例１〜６および比較例１〜４で使用した原材料を一括して以下に示した。（１）熱可塑性ポリイミド樹脂（前記化１の式で表わされる構造のもの；三井東
圧化学社製：オーラムＰＤ４５０）
（２）酸化チタンウィスカ（ｐＨ７）；画像解析装置測定による体面積平均値として繊維長１．６８μｍ、繊維径０．１３μｍのもの、（石原産業社製：ＦＴＬ１００）
（３）硫酸マグネシウムウィスカ（ｐＨ９．５）
（宇部興産社製：モスハイジ）
（４）ＦＥＰ（平均粒径を０．５μｍに粉砕したもの；ダイキン工業社製：ネオフロンＦＥＰ）
（５）ＦＥＰ（平均粒径を２０μｍに粉砕したもの；ダイキン工業社製：ネオフロンＦＥＰ）
（６）ポリアミドイミド樹脂（平均粒径５μｍ以下に粉砕したもの；日立化成社製：ＨＩ−４００）
（７）ポリアミドイミド樹脂 （平均粒径約２５μｍに粉砕したもの；日立化成社製：ＨＩ−４００）
（８）ポリイミド樹脂先駆体（平均粒径５μｍ以下に粉砕したもの；東レ社製：トレニース２０００）
（９）ＰＦＡ（平均粒径を０．５μｍに粉砕したもの；ダイキン工業社製：ネオフロンＰＦＡ）
（10）ＰＦＡ（平均粒径を２０μｍに粉砕したもの；ダイキン工業社製：ネオフロンＰＦＡ）
（11）ＰＴＦＥ（平均粒径５μｍに粉砕したもの；喜多村社製：ＫＴ４００Ｈ）なお、上記平均粒径は、レーザー回折式粒度分析計（日機装社製：マイクロトラックＨＲＡ）を使用してメジアン径を求めた。
【０１３４】
〔実施例１〕
化１で表わされる分子構造を有するポリイミド樹脂１００重量部に対し、酸化チタンウィスカ３０重量部を配合し、乾式混合した後、２軸押出し機を用いてペレットを造粒した。このペレットを射出成形機で成形圧力１５００ｋｇｆ／ｃｍ² 、金型温度２００℃、シリンダー温度３５０〜４２０℃で射出成形して分離爪を得た。
【０１３５】
〔比較例１〕
化１で表わされる分子構造を有するポリイミド樹脂１００重量部に対し、硫酸マグネシウムウィスカ２０重量部を配合し、乾式混合した後、２軸押出し機を用いてペレットを造粒しようと試みたが、多量のガスが発生したため造粒を中止した。造粒されたポリイミド樹脂組成物は、ペレット状をしておらず射出成形ができない状態であったため、以降の作業は中止した。
【０１３６】
〔実施例２〕
実施例１で発生したスプール、ランナーおよび不良品をペレット状に粉砕し、前記同条件で分離爪を作製した。この作業を５回繰り返し、５回再生した材料でペレットを造粒した。このペレットをバージン材（未使用材）と５０重量％均一に混合し、前記射出成形条件で分離爪を成形した。
【０１３７】
〔実施例３〕
実施例２で得た５回再生の材料からなるペレットをバージン材と８０重量％均一に混合し、前記射出成形条件で分離爪を成形した。
【０１３８】
〔比較例２〕
実施例２で得た５回再生の材料からなるペレットを用い、１００％再生材からなる分離爪を前記射出成形条件で製造した。その後、２８０℃、５時間の熱処理を行なった。
【０１３９】
なお、分離爪の形状は、厚さ幅３ｍｍ、先端部曲率半径Ｒ３０μｍとし、乾式静電複写機の定着装置の分離爪と同一形状にした。
【０１４０】
上記分離爪（射出成形された状態そのままのもの、いわゆる「射出成形上がり」）を用い、分離爪基材の特性を以下の試験で調べ、その結果を表１に示した。
【０１４１】
［分離爪基材の評価試験］
（ａ） 耐衝撃性：図１に示す衝撃試験機を用い、レバーの一方の端部を回転自在に支持し、レバーの他方の端部に分離爪を取付け、刃先がローラーの接線に対して約１０°の角度で接触するようにした。その際、レバーの支持部（支点）から刃先までの長さは８５ｍｍであり、刃先の静荷重は２０ｇｆとした。そして、ローラを内装ヒータで２５０℃に加熱し、レバーを図１中鎖線で示す直立状態から落下させて刃先をローラ表面に衝突させ、分離爪の刃先に欠損が生じるまでの衝突回数（最高１０回まで）を調べた。
【０１４２】
（ｂ） 耐疲労性：図２に示す疲労試験機を用い、レバーの一方の端部を回転自在に支持し、レバーの他方の端部に分離爪を取付け、刃先がローラーの接線に対して約１０°の角度で接触するようにした。その際、レバーの支持部（支点）から刃先までの長さは８５ｍｍであり、刃先の静荷重は２０ｇｆとした。そして、レバーの中ほど下方には棒材を介して図示した外形状のカムを設け、このカムを回転させて分離爪の刃先をローラ表面上の１ｍｍの高さから断続的に衝突させた。なお、ローラは内装ヒータで２５０℃に加熱し、１０万回衝突させた後に図３に示す刃先の変形量（ｔ）：μｍを調べた。
【０１４３】
【表１】

【０１４４】
表１に示す結果からも明らかなように、再生材１００％からなる比較例２は、耐衝撃性および耐疲労性が劣っていた。この結果は、ペレットを再生するときにウィスカが粉砕されたため、ウィスカによる補強強化がなくなったためであると考えられる。また、ｐＨが９よりアルカリ側のウィスカを配合した比較例１は、ペレットを造粒できなかった。
【０１４５】
〔実施例４〜６、比較例３、４〕
実施例２と全く同じ分離爪を多数形成し、投影機を利用して先端Ｒを測定し、その先端Ｒが３０μｍであるものを選別した。選別された所定先端Ｒの分離爪の表面に、以下のように調製したプライマー液および非粘着性の被膜用溶液を表２に示す組み合わせで用い、後述の方法により塗布した。
(1)プライマー液１：平均粒径０．５μｍのＦＥＰ１００重量部と、平均粒径５μｍ以下のポリアミドイミド（ＰＡＩ）樹脂１００重量部を均一に混合し、ＮＭＰ２０重量％、キシレン５重量％を含む純水１００重量部に対し、２５重量部を配合し分散させた。
【０１４６】
▲２▼ プライマー液２：平均粒径０．５μｍのＦＥＰ１００重量部と、平均粒径５μｍ以下のポリイミド先駆体５００重量部を均一に混合し、ＮＭＰ２０重量％、キシレン５重量％を含む純水１００重量部に対し、２５重量部を配合し分散させた。
【０１４７】
▲３▼ プライマー液３：平均粒径２０μｍのＦＥＰ１００重量部と、平均粒径２５μｍのポリアミド樹脂３００重量部を均一に混合し、ＮＭＰ２０重量％、キシレン５重量％を含む純水１００重量部に対し、２５重量部を配合し分散させた。
【０１４８】
▲４▼ プライマー液４：平均粒径０．５μｍのＰＦＡ１００重量部と、平均粒径５μｍ以下のポリアミド樹脂３００重量部を均一に混合し、ＮＭＰ２０重量％、キシレン５重量％を含む純水１００重量部に対し、２５重量部を配合し分散させた。
【０１４９】
〔非粘着性被膜の被覆用溶液１〕
ＮＭＰ２０重量％、キシレン５重量％を含む純水１００重量部に対し、平均粒径２０μｍのＰＦＡを２５重量部配合し分散させた。
【０１５０】
〔非粘着性被膜の被膜用溶液２〕
ＮＭＰ２０重量％、キシレン５重量％を含む純水１００重量部に対し、平均粒径２０μｍのＰＦＡを２５重量部および平均粒径約５μｍのＰＴＦＥを２０重量部配合し分散させた。
【０１５１】
上記したように調製したプライマー液および非粘着性被膜の被覆用溶液を被覆するとき、ノズル口径１ｍｍのスプレーガンを用い、分離爪の通紙面と先端Ｒに向かって往復して移動させながら分離爪に所定のコーティング液を塗布した。移動速度は、１秒以上の連続移動時の速度むらが±１０％以内となるようにし、５０〜３００ｍｍ／秒に設定した。５０ｍｍ／秒未満の低速では塗布液が垂れ易く、３００ｍｍ／秒を越える高速では濡れ面が形成され難いからである。また、スプレーガンの霧化吐出圧を３〜６ｋｇｆ／ｃｍ² に設定した。
【０１５２】
また、吹付け距離は、被塗装面とノズル先端との距離が１５０〜２５０ｍｍに設定した。１５０ｍｍ未満の近距離では塗装液が被塗装面に溜まって塗装むらが生じやすくなり、２５０ｍｍを越える遠距離では被塗装面に塗装液が充分に付着する前に霧状の塗装液粒子が乾燥し、塗装面の表面粗さが増すからである。
【０１５３】
上述のようにして、分離爪表面にプライマー液をスプレーコートによって塗布し、雰囲気温度８０℃の乾燥炉で２０分間乾燥させ、プライマー液に含まれる溶剤を完全に蒸発させた。その後、プライマー層のうえから、さらに非粘着性被膜の被膜用溶液をスプレーコートによって塗布し、段階的に３５０℃まで昇温させて、３０分間保持した。この場合の焼成時間の総合計は１２時間であった。
そして、そのまま放置して室温まで徐冷し、分離爪表面にプライマー層を介して非粘着性の被膜を被覆した分離爪を製造した。
【０１５４】
【表２】

【０１５５】
表２に示した組合わせでプライマーを介して非粘着性の被膜を形成した実施例４〜６、比較例３、４の分離爪各３０個づつに対して、先端Ｒのバラツキを投影機を利用して測定し、表２中にその最大値、最小値、その平均値および標準偏差を示した。
【０１５６】
また、実施例４〜６、比較例３、４の分離爪のうち、先端Ｒが４５μｍのもの各３個を選別し、図４に示す摩耗試験機を用いて摺接相手のローラに対する攻撃性および耐摩耗性を、乾式静電複写装置の定着装置の仕様に準ずる条件で、以下に示す試験を行ない、その結果を表３に示した。
【０１５７】
１．相手ローラの攻撃性
図４に示す摩耗試験機に各試験片（分離爪の先端Ｒが４５μｍのもの、各３個）を装着した。すなわち、摩耗試験機のレバーの一方の端部を回転自在に支持し、レバーの他方の端部に分離爪を取付け、刃先がローラの接線に対して約１０°の角度で接触するようにした。その際、レバーの支持部（支点）から刃先までの長さは８５ｍｍであり、刃先の静荷重は２０ｇｆとした。
【０１５８】
分離爪が接する相手ローラーは、Ｓ４５Ｃ製のφ５０ｍｍパイプ材に定着ローラと同じようにＰＦＡを３０μｍの厚みでコーティングしたローラであり、このパイプ材内にヒータを取り付けてローラ表面を２５０℃に加熱した。 そして、ローラに刃先を当接させた状態で、ローラを１４８ｒｐｍの速度で回転させ、４００時間後の相手ローラ表面のＰＦＡ被膜の損傷性を観察し、損傷深さ６μｍ未満を○印、損傷深さ６μｍ以上２０μｍ未満を△印、損傷深さ２０μｍ以上を×印で示した。
【０１５９】
２．耐摩耗性
上記相手ローラの攻撃性で試験した分離爪について、ローラと当接していた刃先の非粘着性被膜の状態を調べた。その評価は、試験終了後の刃先に被膜が被覆されているものを○印、被膜が摩耗してプライマー層が露出しているものを△印、被膜が摩耗して基材がが露出しているものを×印とした。
【０１６０】
【表３】

【０１６１】
表２の結果から、実施例の分離爪は、被膜の膜厚のバラツキが小さく品質が安定していることがわかる。また実施例のなかでもプライマーのバインダーにＰＡＩを採用した実施例４は、バインダーにＰＩを採用した実施例５よりもバラツキが小さく、かつ膜厚も薄く形成されており、剥離性能に優れる良好な品質であった。
【０１６２】
非粘着性の被膜にＰＴＦＥを添加した実施例６は、膜厚および先端ＲのバラツキがＰＴＦＥを添加していないものに比べて若干劣っていたが、表３の結果から耐摩耗性に優れたものであることがわかる。
【０１６３】
これら実施例に対して、プライマーにＰＦＡを採用した比較例４、およびプライマーの固形分の平均粒径が所定範囲を越えて大径の比較例３は、被膜の膜厚のバラツキが大きく、しかも膜厚が不適当に大きくなる傾向があった。また、表３の結果から、プライマーの固形分の平均粒径が所定範囲を越えて大径の比較例３は、相手ローラに対して攻撃性のあることも判明した。
【０１６４】
【発明の効果】
この発明は、以上説明したように、プライマーの主成分をテトラフルオロエチレン−へキサフルオロプロピレン共重合体およびバインダー樹脂としたので、極めて均一な薄厚の層で、耐熱性に優れた分離爪の先端部の刃先形状が、Ｒ４０μｍ程度の極めて鋭利、かつ均一に精密なＲ形状の分離爪およびその製造方法を提供できる利点がある。
【０１６５】
また、プライマー層を介してフッ素系樹脂被膜を形成した分離爪の先端が、所要の鋭利なＲ形状になり、従来より薄いコピー用紙である６０〜７５μｍの薄紙を良好に剥離できる分離爪およびその製造方法を提供できる利点がある。
【０１６６】
また、上記良好な剥離性能の分離爪を製造するために必要な薄膜のフッ素樹脂被覆用プライマーを提供できる利点もある。
【図面の簡単な説明】
【図１】衝撃試験機の概略側面図
【図２】耐疲労性試験機の概略側面図
【図３】分離爪の刃先の変形量の説明図
【図４】相手ローラ攻撃性および耐摩耗性についての試験機概略側面図[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a separation claw to be mounted on an electrophotographic apparatus such as a copying machine or other printing machine, a manufacturing method thereof, and a primer for a separation nail used for undercoating when a surface of the separation nail is coated with a fluororesin coating.
[0002]
[Prior art]
Generally, in an electrophotographic apparatus such as a dry copying machine or other printing machine, an electrostatic charge latent image formed on the outer periphery of a photosensitive drum is converted into a toner image, and the toner image is applied to a sheet of paper supplied from a paper feed cassette. In order to fix the transferred toner image on the paper surface, a fixing device is incorporated in which the toner image and the paper fiber on the paper surface are heated and pressed by a fixing roller to be fused.
[0003]
Since the copy paper that has passed through such a fixing device needs to be reliably discharged without being wound around the roller, the end of the copy paper is scooped up by bringing the tip of the separation claw into close contact with the outer peripheral surface of the roller. .
[0004]
The separation claw is usually made of a plate-shaped separation claw base material, and has a claw tip portion in which a corner portion is formed in a predetermined acute corner shape. This claw tip has a low frictional resistance, does not damage the roller surface, requires mechanical strength such as high-temperature rigidity, and is also required to have non-adhesive (non-adhesive) properties. It is an important part
[0005]
The conventional fixing temperature in a general office copying machine is about 200 ° C., and the heat roller temperature at startup is 230 ° C. at the maximum. In order to shorten the start-up time, the heating temperature of the heat roller becomes higher, the fixing temperature is about 240 ° C., and the heat roller temperature at the start-up is up to 280 ° C.
[0006]
For this reason, the separation claw in contact with the heat roller is also required to have heat resistance that does not cause a problem even if the temperature is always 240 ° C. or higher and does not cause a problem even if the temperature is 280 ° C. or higher.
[0007]
In addition, in order to improve the non-adhesiveness of the surface of the separation nail, which requires such heat resistance, it is known to form a fluorine resin film, and as a fluorine resin film formed thereby, There are the following two types.
[0008]
That is, the first type is a fluororesin film containing a binder, which is, for example, tetrafluoroethylene (hereinafter abbreviated as TFE. The abbreviation is also indicated in parentheses below), tetra. Fluorine resin such as fluoroethylene-hexafluoropropylene copolymer (FEP) and tetrafluoroethylene-perfluoroalkyl vinyl ether copolymer (PFA) and a binder resin such as epoxy resin, phenol resin or polyamide resin are mixed together. It is a film formed by applying a film agent in which the mixture is dispersed with an organic solvent to the surface of the separation nail substrate and baking it.
[0009]
Since the baking temperature of this type of film is the melting point or curing temperature (about 180 to 250 ° C.) of the binder resin, the separation nail substrate has a heat resistance temperature equal to or higher than the melting point or the curing temperature, specifically A synthetic resin having a heat resistant temperature of 250 ° C. or higher is used as the separation claw base material.
[0010]
And when this type of fluororesin coating is baked, the binder resin moves closer to the base material due to the difference in surface energy, and the adhesion is exerted. The fluororesin moves to the surface layer and exhibits non-adhesiveness. .
[0011]
However, this type of fluororesin coating has a drawback that the non-adhesiveness inherent to the fluororesin used cannot be sufficiently exhibited because some binder resin is mixed on the surface of the coating.
[0012]
In addition, the second type fluorine-based resin film that does not contain a binder is a film in which the fluororesin itself is baked on the surface of the separation nail base material at a temperature equal to or higher than the melting point of the fluororesin. The powdery fluororesin melts and there is no boundary between the powders, and a continuous film is formed on the surface.
[0013]
Since the coating film formed in this way is entirely made of a fluororesin, there is an advantage that non-adhesiveness inherent to the fluororesin is exhibited. Examples of the fluororesin that can be used in this type and that are particularly excellent in non-adhesiveness include FEP and PFA. Since these melting points are all 270 ° C. or higher, those having a melting point of 280 ° C. or higher are used as the separation nail substrate.
[0014]
By the way, the second type (a binder-free type) fluorine-based resin film that can exhibit the non-adhesiveness inherent to the fluorine-based resin is excellent in non-adhesiveness, and therefore has good adhesion to the separation nail substrate. It becomes insufficient. In order to provide such a coating with adhesion to the substrate, a primer layer is interposed between the fluororesin coating and the separation nail substrate to enhance the adhesion between the separation nail substrate and the fluorine resin coating. .
[0015]
Since the above-mentioned primer firmly adheres the base material and the coating, it is generally formed from a material having a high affinity with each material. Usually, a primer in which a binder resin and a fluororesin with good adhesion are dispersed in a solvent is used for the synthetic resin base of the separation nail. When using, a primer is first coated on the surface of the separation nail base and dried. Subsequently, a coating agent containing a fluorine resin as a main component is coated by spraying or the like, and then baked (melted) at a melting point or higher of the fluorine resin.
[0016]
If it does in this way, it will be in the state where two layers which consist of a primer layer with a thickness of about 5-30 micrometers and a fluorine resin layer with a thickness of about 5-30 micrometers were piled up on the surface of a separation claw base material.
[0017]
As such a separation claw, there is one described in Japanese Patent Publication No. 7-86726. In this separation claw, the surface of a separation claw made of polyimide resin is coated with a primer mainly composed of PFA and polyimide resin as a binder, and further coated with PFA.
[0018]
[Problems to be solved by the invention]
By the way, in recent years, the thickness of copy paper tends to be reduced from 60 to 75 μm from the conventional 80 to 90 μm.
[0019]
This is done in response to demands for environmental protection against pulp demand and space saving when managing documents. When such thin copy paper is loaded into a copying machine, etc., continuous operation is performed. In this case, the sheet is liable to be peeled off.
[0020]
There are many possible causes of the peeling failure. One of them is that the tip shape of the separation claw does not match the thickness of the copy paper. In order to separate the copy paper smoothly, it is essential that the tip of the separation claw be in the range of the radius of curvature (R) of 2/5 to 4/5 of the thickness of the copy paper.
[0021]
That is, in order to peel the conventional copy paper having a thickness of 80 to 90 μm from the fixing roller without any problem, the tip R of the separation claw may be in the range of 30 to 65 μm. When copying paper is used, a separation claw with a tip R of 65 μm increases the probability of occurrence of a peeling failure.
[0022]
The inventor of the present application considers that it is necessary to control the thickness of the fluororesin coating coated on the surface of the blade edge of the separation claw in order to form a separation claw that does not cause poor peeling even when thin copy paper is used. It was.
[0023]
In addition, as an approach to environmental problems, it is preferable to recycle sprue and runners that are generated when the separation claw is injection molded, or non-standard defective products, but in general, recycled materials are used in the heat history of injection molding and during grinding. Since the physical properties have been lowered by shearing, it has been difficult to use in applications that require high temperature impact resistance and fatigue resistance such as separation claws.
[0024]
The present invention solves all of the above-mentioned problems and has all of the impact resistance, wear resistance, fatigue resistance and non-adhesiveness to the toner required for the separation claw at a predetermined high temperature. It is an object of the present invention to provide a separation claw having a sharp-shaped cutting edge with a radius of curvature of less than R60 μm that can reliably separate a thin copy paper having a thickness of 60 to 75 μm.
[0025]
That is, the first object of the present invention is to solve the above-mentioned problems and to form a fluorine-based resin film on the surface of a separation nail substrate having impact resistance, wear resistance and fatigue resistance via a primer. In doing so, it is an object to provide a separation claw having an extremely sharp and uniform R shape, and a method of manufacturing the same.
[0026]
A second object of the present invention is to form a separation claw having a fluororesin film formed through a primer layer into a sharp R shape at the above-mentioned required claw tip and reduce the thickness to 60 to 75 μm. It is another object of the present invention to provide a separation claw that can be satisfactorily peeled even on a sheet of paper and a method for manufacturing the same.
[0027]
A third object of the present invention is to provide a primer for coating a thin film fluororesin capable of producing a separation claw having a good peeling performance.
[0028]
[Means for Solving the Problems]
In order to solve the first and second problems, the average particle size is at least on the surface of the cutting edge of the separation nail substrate made of a resin composition containing a thermoplastic polyimide resin as a main component and a whisker having a pH of 9 or less. One or more resins selected from the group consisting of a polyamideimide resin having a diameter of 0.3 to 5 μm, a polyimide resin and a precursor thereof, and a tetrafluoroethylene-hexafluoropropylene copolymer having an average particle diameter of 0.1 to 10 μm A separating nail is provided in which a primer layer is provided and a continuous film mainly composed of a perfluoroalkyl vinyl ether copolymer is baked and coated thereon.
[0029]
As the film, a film in which 0.1 to 30% by weight of polytetrafluoroethylene powder is blended with a perfluoroalkyl vinyl ether copolymer can be employed.
[0030]
Moreover, as a synthetic resin which forms the said separation nail | claw base material, the thermoplastic polyimide resin containing 80 weight% or less of reproduction | regeneration thermoplastic polyimide resins is employable.
[0031]
Alternatively, a polyamideimide resin or a polyimide resin having an average particle size of 0.3 to 5 μm on at least the blade edge surface of a separation nail substrate made of a resin composition containing a thermoplastic polyimide resin as a main component and a whisker having a pH of 9 or less And a primer solution containing one or more resins selected from the group consisting of precursors thereof and a tetrafluoroethylene-hexafluoropropylene copolymer having an average particle size of 0.1 to 10 μm and dried, and then A solution containing a perfluoroalkyl vinyl ether copolymer as a main component was applied and dried, and then fired at 340 to 380 ° C. to form a non-adhesive continuous film on the surface of the separation nail to produce a separation nail. It is.
[0032]
Further, in order to solve the third problem, a primer for undercoating when a coating mainly composed of a fluororesin is baked and coated on the surface of at least a tip portion of a synthetic resin separation nail substrate. The separation nail primer is composed mainly of tetrafluoroethylene-hexafluoropropylene copolymer and binder resin.
[0033]
Since the separation nail of the present invention uses a thermoplastic polyimide resin, it can form a separation nail excellent in heat resistance and can be injection-molded. Therefore, a high-precision separation nail can be efficiently manufactured, and the production cost Can be kept low.
[0034]
Further, in the invention using limited use of whiskers having a pH of 9 or less, it is possible to use a recycled material of polyimide resin, and it is possible to reduce the price of the product by using the recycled material. Recycled materials can be blended up to 80% by weight of the resin composition, and if blended in excess of 80% by weight, physical properties such as impact resistance, wear resistance, and fatigue resistance of the resin composition are lowered. The required characteristics of the separation claw cannot be satisfied.
[0035]
In addition, one or more resins selected from the group consisting of a polyamideimide resin having an average particle size of 0.3 to 5 μm, a polyimide resin and a precursor thereof, and a tetrafluoroethylene-hexafluoropropylene copolymer having an average particle size of 0.1 to 10 μm. By providing a primer layer containing a polymer, a continuous film of a separation claw base material and a fluororesin mainly composed of a perfluoroalkyl vinyl ether copolymer is firmly bonded, and the primer layer is very Thinly separated nails.
[0036]
The separation claw in which the fluorine-based resin film is formed through the primer layer made of such a predetermined component becomes an R-shaped separation claw having a sharp nail tip that can favorably peel the thin paper.
[0037]
Further, since the non-adhesive fluororesin film is mainly composed of a perfluoroalkyl vinyl ether copolymer and baked at 340 to 380 ° C., a continuous non-adhesive film having a uniform film thickness can be formed on the surface of the separation nail. .
[0038]
DETAILED DESCRIPTION OF THE INVENTION
The thermoplastic polyimide resin used in the present invention is represented by the general formula shown in the following chemical formula 1.
[0039]
[Chemical 1]

[0040]
(In the formula, X represents a group selected from the group consisting of a direct bond or a divalent hydrocarbon group having 1 to 10 carbon atoms, a hexafluorinated isopropylidene group, a carbonyl group, a thio group, an ether group and a sulfone group. R ₁ ~ R _Four Represents hydrogen, a lower alkyl group having 1 to 6 carbon atoms, a lower alkoxy group having 1 to 6 carbon atoms, chlorine or bromine, which may be the same or different. Y has 2 to 27 carbon atoms, and an aliphatic group, a cycloaliphatic group, a monocyclic aromatic group, a condensed polycyclic aromatic group, or an aromatic group directly or directly linked by a cross-linking member It represents at least one tetravalent group selected from the group consisting of condensed polycyclic aromatic groups. )
Further, a specific example of Y in the above formula 1 is a tetravalent group represented by the following chemical formula 2.
[0041]
[Chemical formula 2]

[0042]
The thermoplastic polyimide resin used in the present invention is obtained by dehydrating and cyclizing a polyamic acid obtained by reacting an ether diamine represented by the following chemical formula 3 with at least one tetracarboxylic dianhydride as a diamine component.
[0043]
[Chemical 3]

[0044]
In the ether diamine represented by Chemical Formula 3, R ₁ ~ R _Four As a typical example in which all are hydrogen atoms, there is a thermoplastic polyimide resin marketed by Mitsui Toatsu Chemical Co., Ltd. under the trademark “AURAM”. The manufacturing method is disclosed in Japanese Patent Application Laid-Open Nos. 61-143478, 62-68817, and 62-86021.
[0045]
Since this thermoplastic polyimide resin exhibits thermoplasticity while maintaining the heat resistance inherent to the polyimide resin, it can be molded relatively easily by compression molding, injection molding, extrusion molding or other melt molding methods.
[0046]
Moreover, what is shown below is mentioned as a specific example of the diamine shown by the formula 3 above. That is, bis [4- (3-aminophenoxy) phenyl] methane, 1,1-bis [4- (3-aminophenoxy) phenyl] ethane, 1,2-bis [4- (3-aminophenoxy) phenyl] Ethane, 2,2-bis [4- (3-aminophenoxy) phenyl] propane, 2- [4- (3-aminophenoxy) phenyl] -2- [4- (3-aminophenoxy) -3-methylphenyl ] Propane, 2,2-bis [4- (3-aminophenoxy) -3-methylphenyl] propane, 2- [4- (3-aminophenoxy) phenyl] -2- [4- (3-aminophenoxy) -3,5-dimethylphenyl] propane, 2,2-bis [4- (3-aminophenoxy) -3,5-dimethylphenyl] propane, 2,2-bis [4- (3-aminophenoxy) ) Phenyl] butane, 2,2-bis [4- (3-aminophenoxy) phenyl-1,1,1,3,3,3-hexafluoropropane, 4,4′-bis (3-aminophenoxy) biphenyl 4,4′-bis (3-aminophenoxy) -3-methylbiphenyl, 4,4′-bis (3-aminophenoxy) -3,3′-dimethylbiphenyl, 4,4′-bis (3-amino Phenoxy) -3,5-dimethylbiphenyl, 4,4′-bis (3-aminophenoxy) -3,3 ′, 5,5 ′ tetramethylbiphenyl, bis [4- (3-aminophenoxy) phenyl] ketone, Examples include bis [4- (3-aminophenoxy) phenyl] sulfide, bis [4- (3-aminophenoxy) phenyl] sulfone, and the like. These may be used alone or in combination of two or more. It can be.
[0047]
Further, other diamines can be mixed and used within a range that does not impair the melt fluidity of the thermoplastic polyimide resin. Examples of the diamine that can be used as a mixture include m-aminobenzylamine, p-aminobenzylamine, 3,3′-diaminodiphenyl ether, 3,4′-diaminodiphenyl ether, 4,4′-diaminodiphenyl ether, 3,3'-diaminodiphenylsulfide, 3,4'-diaminodiphenylsulfide, 4,4'-diaminodiphenylsulfide, 3,3'-diaminodiphenylsulfone, 3,4'-diaminodiphenylsulfone, 4,4'- Diaminodiphenylsulfone, 3,3′-diaminobenzophenone, 3,4′-diaminobenzophenone, 4,4′-diaminobenzophenone, 1,3-bis (3-aminophenoxy) benzene, 1,3-bis (4-amino) Phenoxy) benzene, 1,4-bis (3-amino) Enoxy) benzene, 1,4-bis (4-aminophenoxy) benzene, 2,2-bis [4- (4-aminophenoxy) phenyl] propane, 4,4′-bis (4-aminophenoxy) biphenyl, 4 , 4'-bis (4-aminophenoxy) ketone, bis [4- (4-aminophenoxy) phenyl] sulfide, bis [4- (4-aminophenoxy) phenyl] sulfone, etc., and these diamines are usually 30 mol% or less, preferably 5 mol% or less can be mixed and used.
[0048]
The thermoplastic polyimide resin particularly preferably used in the present invention is obtained by reacting the diamine and tetracarboxylic dianhydride in an organic solvent and dehydrating and ring-closing the resulting polyamic acid. The tetracarboxylic dianhydride used is represented by the following formula 4 (wherein Y is the same as in the case of the above-described formula 4).
[0049]
[Formula 4]

[0050]
Specific examples of the tetracarboxylic dianhydride represented by the formula 4 include, for example, ethylenetetracarboxylic dianhydride, 1,2,3,4-butanetetracarboxylic dianhydride, and cyclopentanecarboxylic acid dianhydride. Anhydride, pyromellitic dianhydride, 3,3 ′, 4,4′-benzophenone tetracarboxylic dianhydride, 2,2 ′, 3,3′-benzophenone tetracarboxylic dianhydride, 3,3 ′ , 4,4′-biphenyltetracarboxylic dianhydride, 2,2 ′, 3,3′-biphenyltetracarboxylic dianhydride, bis (3,4-dicarboxyphenyl) ether dianhydride, bis (3 , 4-Dicarboxyphenyl) sulfone dianhydride, 1,1-bis (2,3-dicarboxyphenyl) ethane dianhydride, bis (2,3-dicarboxyphenyl) methane dianhydride, bis (3 , 4-dicarboxyphenyl) methane dianhydride, 2,3,6,7-naphthalene tetracarboxylic dianhydride, 1,4,5,8-naphthalene tetracarboxylic dianhydride, 1,2,5 6-naphthalenetetracarboxylic dianhydride, 1,2,3,4-benzenetetracarboxylic dianhydride, 3,4,9,10-berylenetetracarboxylic dianhydride, 2,3,6,7 -Anthracene tetracarboxylic dianhydride, 1,2,7,8-phenanthrenetetracarboxylic dianhydride, 4,4 '-(p-phenylenedioxy) diphthalic dianhydride, 4,4'-(m -Phenylenedioxy) diphthalic dianhydride and the like. And these tetracarboxylic dianhydrides are used individually or in mixture of 2 or more types.
[0051]
Further, when the above polyimide resin is produced, a polyimide resin having a molecular end sealed by reacting aromatic dicarboxylic anhydrides such as phthalic anhydride or aromatic monoamines such as aniline in the coexistence. Can be used.
[0052]
Among such thermoplastic polyimide resins, the most preferable polyimide resin is represented by the general formula (1), in which (a) X is directly connected, (b) Y is a monocyclic aromatic ring, and (c) R ₁ ~ R ₂ Satisfy at least one, preferably all of the conditions a to c that are all hydrogen atoms, and the above X, Y, R ₁ ~ R _Four If the polyimide component satisfying all of the above is a thermoplastic polyimide resin containing 50% by weight or more, preferably 70% by weight or more, more preferably 80 to 100% by weight of the whole polymer, heat resistance is obtained. The moldable melt viscosity is achieved, and the separation claw tip R can be accurately injection molded. Examples of such thermoplastic polyimide resin include Aurum manufactured by Mitsui Toatsu Chemical Co., Ltd.
[0053]
As the fibrous reinforcing material for reinforcing the synthetic resin in the present invention, a whisker having a pH of 9 or less, preferably pH 4 to 9, more preferably pH 5 to 8 is used. The whisker is a needle-like (basket-like) single crystal or polycrystal, and the size of the crystal is 0.01 to 10 μm in average diameter, and generally 0.1 to 50 μm in average fiber diameter. These are short fibers having an average fiber length of 1 to 300 μm, and these reinforce the tip of the separation claw well. More preferable fiber dimensions are an average fiber diameter of 0.1 to 1 μm and an average fiber length of 1 to 100 μm. The aspect ratio of such whiskers is 1 to 200, generally 10 to 100.
[0054]
Such whiskers are considered to have an average fiber length of about 10 μm or less, preferably less than 1 μm or less, which is finally melted and mixed and broken during the molding process to be finally contained in the molded body. .
[0055]
The reason for limiting the pH of the whisker to 9 or less is that whisker exhibiting alkalinity or extreme acidity exceeding pH 9 may destroy a bonding group related to an imide bond or an ether bond of the polyimide resin. This is because physical properties and dimensional accuracy are lowered. Moreover, when the whisker outside the range of the predetermined pH value is exposed on the surface of the separation nail substrate, an adverse effect on the primer resin layer coated on the surface is expected.
[0056]
Specific examples of the acidic whisker having a pH of 9 or less include a general formula TiO such as a rutile white needle crystal. ₂ Titanium oxide whiskers (pH 6-8), 9Al ₂ O _Three ・ 2B ₂ O _Three 2Al ₂ O _Three ・ B ₂ O _Three White boric acid whisker whisker (pH 7-8), etc., which are indicated by the above, etc., whitened by adding S (sulfur) to these, and yellow containing impurities such as Pb and Cd And zinc oxide whisker (pH 7) represented by the general formula ZnO in which the shape is a tetrapod or gray, or these are broken into a cone or taper. K ₂ O · 6TiO ₂ , K ₂ O · 6TiO ₂ ・ 1 / 2H ₂ O or K ₂ Ti ₂ O _Five , K ₂ Ti _Four O ₉ , K ₂ Ti ₆ O ₁₃ , K ₂ Ti ₈ O ₁₇ General formula K ₂ O · nTiO ₂ A potassium titanate whisker (pH 7 to 9) represented by (n is an integer of 1 or more or an even number of 2 or more) is also included.
[0057]
Since the above whiskers have a very small diameter within a predetermined range and are short fibers, the tip R shape with good dimensional accuracy and reinforced by injection molding a heat-resistant resin material containing them. A separation nail having However, if the average diameter or average length of the above whiskers is smaller than the predetermined range, there is no reinforcing effect, and if the average diameter or average length is larger than the predetermined range, a precise R shape of the separation claw is formed. It is difficult to do.
[0058]
In addition, in order to improve the wettability and bondability between the whisker and the synthetic resin that forms the separation claw such as polyimide resin, the surface of the whisker is treated with a coupling agent such as aminosilane or epoxysilane. Is preferred.
[0059]
The blending ratio of the fibrous reinforcing material such as the whisker is preferably 1 to 50% by weight in the synthetic resin. The reason is that if the blending ratio is less than the predetermined amount, there is no appropriate reinforcing effect, and if the blending ratio exceeds the predetermined ratio, the moldability by injection molding is deteriorated. In addition, as another factor, it causes a problem such as a short shot of injection molding, and it becomes difficult to accurately form the R shape of the tip of the separation claw. From such a tendency, the blending ratio of the fibrous reinforcing material such as whisker is 5 to 50% by weight, more preferably 10 to 40% by weight, and particularly preferably 10 to 30% by weight.
[0060]
Here, the mixing means such as thermoplastic polyimide resin (TPI) and whisker may be supplied individually to the melt mixer, but these are previously mixed with a general-purpose mixer such as a Henschel mixer, tumbler mixer, ribbon blender. After dry mixing, it may be supplied to a melt mixer, and its specific method is not particularly limited.
[0061]
If the strength of the entire separation claw can be improved within a range that does not impair the effects of the present invention, that is, while maintaining the precise shape of the distal end of the separation claw, other needle-like fiber reinforcements (for example, Glass fiber, carbon fiber, graphite fiber, ceramic fiber, rock wool, slag wool, silicon carbide whisker, sapphire whisker, wollastonite, steel wire, copper wire, stainless steel wire, silicon carbide fiber) may be added, Furthermore, antioxidants, heat stabilizers, ultraviolet absorbers, lubricants, mold release agents, colorants, flame retardants, antistatic agents, crystallization accelerators, and the like may be added as appropriate. Also for these fillers, it is preferable to use those having a pH value similar to that described above because the resin material is not adversely affected.
[0062]
The molding material mixed as described above is heated to a temperature range of about 390 to 450 ° C. and plasticized, and then filled in a mold heated to 150 to 250 ° C., and 1000 to 2000 kgf / cm. ² The desired separation claw is obtained by solidifying and releasing at a molding pressure of.
[0063]
The reason for heating to the high temperature is that the melting point of the predetermined polyimide resin is about 388 ° C. and about 380 to 400 ° C. depending on the measurement conditions. Further, by subjecting the separation claw to a predetermined heat treatment, it is possible to obtain a long-life separation claw for a copying machine having excellent heat distortion resistance, dimensional stability, and wear resistance.
[0064]
The heat treatment is preferably performed at a glass transition point (for example, 250 ° C.) or higher of a predetermined polyimide resin, and needs to be performed in the range of about 250 to 340 ° C., preferably about 270 to 330 ° C. This is because if the temperature exceeds about 340 ° C., significant thermal deformation occurs in the separation claw, which is not preferable for practical use. On the other hand, if the temperature is less than about 250 ° C., improvement in heat distortion resistance cannot be obtained.
[0065]
Although the heat treatment time varies greatly depending on the heating temperature, it requires at least 2 minutes or more, and sometimes several weeks. In other words, according to the present invention, there is a certain rule between improvement in heat resistance of the separation claw and change in density due to heat treatment, and the density of the polyimide component in the molding material is increased by at least 1.5% or more. The time required for the heat treatment may be the heat treatment time. Here, the density increase rate of the polyimide component can be calculated by measuring the density of the separation claws before and after the heat treatment in accordance with ASTM-D792, and from the blending ratio and density of each component in the molding material.
[0066]
Accordingly, the heat treatment time is about 12 hours or more at about 270 ° C. heating condition, about 1 hour or more at about 280 ° C. heating condition, about 10 minutes or more at about 300 ° C. heating condition, about 2 minutes or more at about 330 ° C. heating condition It has been found that about 10 minutes or more are required under heating conditions of about 340 ° C., and the required time is minimized under heating conditions of about 330 ° C.
[0067]
In addition, in the case of heat treatment at about 260 ° C. or less, it takes several weeks or longer, and on the other hand, in the case of heat treatment at about 340 ° C. or more, significant deformation is caused in the separation claw, so in any case, it is practical. Not. The heat treatment time may be about the same as the baking time of the fluorine coating described later, and may be about 1 to 10 hours, for example.
[0068]
Such heat treatment of the separation claw is performed in a heating device in which the separation claw is controlled to a predetermined temperature, but the type of the heating device is not particularly limited. However, the electric heating method is usually convenient, and as the atmosphere in the apparatus, for example, a hot air circulation method or a hot air circulation method can be used.
[0069]
By performing the heat treatment as described above, the heat resistance of the separation nail base material is improved, and the surface of the separation nail base material at a temperature equal to or higher than the melting point of the fluorine resin is applied to the coating described below, which is mainly composed of a fluorine resin. It becomes possible to bake and coat.
[0070]
After forming the base material of the separation nail as described above, a non-adhesive film mainly composed of a perfluoroalkyl vinyl ether copolymer (hereinafter abbreviated as PFA) is formed on at least the blade surface of the separation nail. However, since PFA has poor adhesion to the separation nail substrate, it is necessary to interpose a primer.
[0071]
This primer layer comprises a tetrafluoroethylene-hexafluoropropylene copolymer (hereinafter abbreviated as FEP) having an average particle size of 0.1 to 10 μm, a polyamideimide resin and a polyimide resin having an average particle size of 0.3 to 5 μm. And a primer containing at least one selected from the group consisting of precursors thereof (also referred to as precursors). The primer layer is formed by applying a primer solution in which the above components are dissolved or dispersed in a solvent to the surface of the separation claw and drying the solvent.
[0072]
Incidentally, the physical properties of FEP used as a primer, PFA forming a non-adhesive fluororesin film, and PTFE are as follows.
[0073]
The crystal melting point of FEP is 253 to 282 ° C., the crystal melting point of PFA is 302 to 310 ° C., and the crystal melting point of PTFE is 327 ° C. or higher.
[0074]
FEP, PFA and PTFE are all perfluoro-type fluororesins, and the carbon atoms that are the skeleton of the molecular structure are completely surrounded by fluorine atoms or trace amounts of oxygen atoms. It is preferable in that it has excellent properties such as heat resistance, chemical resistance, non-adhesiveness, and low friction coefficient. Among such fluororesins, the melt viscosity of PFA and FEP is, for example, 10 at 380 ° C. in terms of the specific melt viscosity according to the evaluation method of ASTM-D3307. ^Four -10 ^Five Poise, 4 × 10 ^Four ~ 1x10 ^Five It is a poise and can be easily melted at a temperature equal to or higher than the melting point and fused to the substrate.
[0075]
The FEP is a trifluoromethyl group (—CF _Three ) In the side chain, PFA is ether side chain or perfluoroalkoxy side chain (C _n F _{2n + 1} ) And a modified product of a homopolymer PTFE and a monomer containing a perfluoroalkoxy group or a hexafluoropropyl group, and PTFE and a comonomer that gives the side chain are essential. It is a copolymer as a component.
[0076]
Such PFA and FEP have a specific melt viscosity of 1 × 10 5 at 370 to 380 ° C., specifically 372 ± 1 ° C., according to the evaluation method of ASTM-D3307. ^Three ~ 1x10 ⁶ It is a poise. The melt flow index (same as the melt flow rate) is 0.8 to 36 g / 10 minutes, preferably 0.8 to 18 g / 10 minutes, and FEP is 0.8 to 12 g / 10 minutes, and contains hexafluoropropylene. Although what is 4-12 g / 10min (ASTM-D3307) is preferable by quantity, it does not need to be specified by such evaluation content.
[0077]
The alkyl group has about 1 to 10 or 1 to 4 carbon atoms, each of which may be in the state of methyl group, ethyl group, propyl group, butyl group, etc. The number of the groups is at least one or more, each alone or 0.1 to 10% by weight, preferably 1 to 8% by weight, or 3 to 6% by weight, or the FEP hexafluoropropylene moiety is 8 to 16%. If it is contained in a proportion of 8% by weight, preferably 8 to 10% by weight, it will have a suitable melt viscosity, excellent film forming moldability, and can form a film with excellent heat resistance on the surface of the separation nail. .
[0078]
As described above, the reason why the FEP has an average particle diameter of 0.1 to 10 μm is that the primer layer is made as thin as possible to form a uniform film thickness. If the average particle size exceeds 10 μm, a uniform film thickness cannot be formed.
[0079]
A polyamideimide resin, a polyimide resin and a precursor thereof having an average particle diameter of 0.3 to 5 μm, which are binder components for binding the FEP component of the primer, will be described below.
[0080]
Polyamideimide resin is characterized by having both an amide bond and an imide bond in the molecular structure. For example, reaction between an aromatic diamine having an amide group and an aromatic tetravalent carboxylic acid such as pyromellitic acid, trimellitic anhydride Or the like, and a diamine such as 4,4′-diaminodiphenyl ether, a dibasic acid having an aromatic imide ring, and a diamine.
[0081]
A specific chemical structure is shown in the following chemical formula 5 as a representative example.
[0082]
[Chemical formula 5]

[0083]
(Wherein n represents an integer, R ₇ Represents a hydrogen atom, a methyl group or a phenyl group, R _Five Represents a trivalent aromatic group containing at least one benzene ring, R ₆ Represents a divalent organic group. )
In addition, R in Chemical formula 5 _Five A specific example of is shown in Chemical Formula 6 below.
[0084]
[Chemical 6]

[0085]
In addition, R in the above-mentioned chemical formula 5 ₆ A specific example of — (CH ₂ ) _m -A saturated aliphatic hydrocarbon group represented by the formula (wherein m represents an integer of 4 to 12) or an aryl group represented by the following formula 7.
[0086]
[Chemical 7]

[0087]
Specific examples of the polyamide-imide resin as described above include the resins shown in the following chemical formulas 8 to 11 or the American Amoco Corporation AI shown in the chemical formula 11 below.
[0088]
[Chemical 8]

[0089]
[Chemical 9]

[0090]
[Chemical Formula 10]

[0091]
Embedded image

[0092]
The polyimide resin is obtained by reaction of an aromatic tetravalent carboxylic acid anhydride (such as pyromellitic anhydride) and an aromatic diamine (such as diaminodiphenyl ether), including those described in detail for the base material of the separation nail described above. It is a high molecular polymer having an imide bond in the molecule.
[0093]
A specific example of the polyimide resin is shown by the following chemical formula (12).
[0094]
Embedded image

[0095]
Examples of commercially available products of these polyimide resins include RYRE-ML, PYRALIN, and the like manufactured by DuPont represented by the following chemical formula (13).
[0096]
Embedded image

[0097]
These precursors are those having a low molecular weight, which undergo condensation polymerization by heating to produce a polymer for binders such as a high molecular weight polyamideimide resin or polyimide resin.
[0098]
As described above, the reason for limiting the average particle size to 0.3-5 μm for the size of the polyamideimide resin, polyimide resin, or precursor polymer for those precursors is to make the primer layer as thin as possible. This is to make the film thickness uniform. When the average particle diameter is larger than 5 μm, the primer layer cannot be formed with a uniform film thickness.
[0099]
The blending ratio of FEP and the above-mentioned binder polymer is 80 to 600 parts by weight of the binder polymer with respect to 100 parts by weight of FEP. By setting it as such a mixture ratio, a primer layer can couple | bond a separation nail | claw base material and a non-adhesive film firmly. When the blending ratio of the binder polymer is outside such a predetermined range, the adhesion strength between the separation nail substrate and the non-adhesive film by the primer layer does not reach the expected level.
[0100]
As described above, the primer is used as a primer solution by dispersing or dissolving the binder polymer in water such as pure water or in solvents, and the solvents include ketones such as methyl ethyl ketone, methyl glycol acetate, and the like. , 2-nitropropane, ethylene glycol acetate, cresyl acid, xylenes, toluene and other aromatic hydrocarbons, N, N-dimethylformamide, N, N-dimethylacetamide, N-methyl-2-pyrrolidone (NMP) And aprotic polar solvents such as Of course, a mixed solvent may be used.
[0101]
The blending ratio of the solvent is 5 to 40% by weight, preferably 10 to 30% by weight of an aprotic polar solvent such as NMP, and 1% of an aromatic hydrocarbon solvent such as xylene in 100% by weight of the solution. If it is -20% by weight, preferably 3-10% by weight, and the balance is water such as pure water, the resin solid content in this solution is difficult to precipitate and solidify, and if properly stirred before coating, The resin solid content is considered preferable because it is appropriately dispersed in the solution.
[0102]
The solid component consisting of FEP and the binder polymer in the primer solution is 5 to 100 parts by weight, preferably 10 to 30 parts by weight, based on 100 parts by weight of the solvent. If the amount of the solid component is less than 5 parts by weight, the primer layer is not sufficiently formed continuously on the surface of the separation nail. If the amount exceeds 100 parts by weight, the nozzle of the atomizer such as a spray gun is clogged. In some cases, the efficiency of the operation is reduced, and the primer layer becomes thicker than necessary, so that the precise tip shape of the separation claw cannot be formed.
[0103]
As a commercially available primer solution that satisfies all of the above conditions, polyflon TFE enamel manufactured by Daikin Industries, Ltd. can be used.
[0104]
Next, the non-adhesive film which has a fluororesin as a main component is demonstrated.
This coating may be 100% PFA, but may also be a composite coating in which PTFE is added in an amount of 1 wt% to 30 wt% to improve wear resistance. However, a film having a PTFE content exceeding 30% by weight is not preferable because the film has a non-uniform film thickness.
[0105]
When such a non-adhesive film is coated on the separation nail substrate via a primer, it is liquefied by dissolving or dispersing in a solvent in the same manner as in the above-described primer use state. The mixing ratio of the solvent and the solid component at that time is the same as that of the primer solution described above, and the description is omitted here.
[0106]
The temperature at the time of coating (application process) for the primer solution and the non-adhesive film is preferably room temperature. This is because the coating liquid has an appropriate viscosity at room temperature and can prevent dripping.
Incidentally, the viscosity measurement method in Ford Cup # evaluates the viscosity by measuring the time for 100 ml of paint in the cup to flow out through an orifice having an inner diameter of 0.162 inch (0.411 cm).
[0107]
As the coating method, for example, an atomizing coating method (spray coating) such as spraying, a dipping method (dipping), or the like can be adopted. In the atomization method, the coating liquid becomes fine particles and adheres to the object to be coated, so that the thickness of the coating film can be accurately formed. The dipping method is preferable because the yield of the coating solution can be improved and the coating solution is not wasted.
[0108]
In the present invention, in order to improve the dimensional accuracy of the tip portion of the separation claw, it is appropriate to form the coating by an atomization coating method that can form a coating film with high accuracy. At this time, the atomization discharge pressure is 2 to 6 kgf / cm. ² , Preferably 3-5kgf / cm ² It is. This is because if the discharge pressure is too low, the mist-like particles become coarse, and if it is too high, a large amount of coating solution is scattered and is easily wasted.
[0109]
After applying the primer solution to the separation claws as described above, for example, the solvent content of the primer solution is evaporated in a drying oven at an ambient temperature of 80 to 120 ° C. for 10 to 30 minutes, and then the non-adhesive coating dispersion is prepared. Apply. Then, the separation nail is baked at a maximum holding temperature of 340 to 380 ° C., and a non-adhesive film is adhered to the separation nail uniformly and firmly.
[0110]
In the firing step, stepwise temperature increases such as room temperature, 80 ° C., 130 ° C., 180 ° C., 230 ° C., 280 ° C. are performed until the predetermined temperature is reached, that is, in the range of 15 to 180 minutes. By gradually raising the temperature every 60 minutes, the curing of the binder resin proceeds gradually and reliably, and a film having uniform adhesion strength can be formed.
[0111]
In addition, when the temperature is raised to 100 to 120 ° C., if kept at a constant temperature for 15 to 60 minutes, even if a very small amount of moisture or solvent is contained in the resin film after the preliminary drying, it is completely dried, The next stage firing can be performed.
[0112]
The maximum holding temperature after the temperature is raised stepwise in this way is a temperature that is about 30 to 70 ° C. higher than the melting point of the fluororesin, and is good if it is baked for 15 to 60 minutes, preferably about 30 minutes. can get. If the holding time is shorter than that, the curing of the binder resin becomes unstable, and if the holding time is long, there is a concern about the occurrence of “warping”, resulting in poor productivity and quality. What is necessary is just to adjust the heating time (total of all processes) including each said temperature stage in the range of 2-24 hours, for example, Preferably it is 3-15 hours.
[0113]
By the way, when the coating is baked by heating rapidly in a short time, the above-mentioned moisture and other solvents are vaporized beyond the boiling point, and the film is foamed and swelled (so-called “flick”, “dent”, “ "Waki", "I", "Fukure") may occur.
[0114]
The cooling after the firing step may be performed in a step reverse to the stepwise temperature increase described above, or may be gradually gradually cooled over a period of about 60 to 180 minutes. If cooled in this way, the coating film and the covering can be in close contact with each other, and a separation claw with high dimensional accuracy can be manufactured.
[0115]
The reason for limiting the firing temperature to 340 to 380 ° C. is that the FEP-containing primer layer and the non-adhesive coating are not thinned at a low temperature of less than 340 ° C., and in particular, the PFA of the non-adhesive coating is not completely melted. This is because it is difficult to form a continuous film. Further, a high firing temperature exceeding 380 ° C. causes adverse effects such as thermal adverse effects such as a decrease in physical properties of the separation nail substrate and decomposition.
[0116]
The melting point (270 ° C.) of the FEP of the primer layer is about 40 ° C. lower than the melting point (310 ° C.) of PFA which is a non-adhesive film component. It is considered that due to the difference in melting point, the primer layer could be a thin film of 5 μm or less while maintaining the adhesive strength.
[0117]
Thus, when the film thickness of the primer layer becomes uniform, the separation claw tip R on which the fluororesin film is formed also has a stable shape with little variation. Therefore, it becomes possible to manage the film thickness to keep the tip R of the separation claw immediately after injection molding constant, and it becomes a separation claw that can satisfactorily separate 60-75 μm thin paper.
[0118]
The tip R of such a separation claw is set to be 2/5 to 4/5 of the thickness of the copy paper. Specifically, considering that the thickness of the copy paper is 60 to 75 μm, the tip R of the separation claw is 30 to 65 μm, preferably 30 to 60 μm.
[0119]
If the leading end R of the separation claw is larger than the sheet member such as paper, it becomes difficult to peel the sheet member satisfactorily, causing a paper jam (jam). Further, if the tip R is smaller than a predetermined range, the tip portion may be damaged when the separation claw is handled. In order to obtain such a tip R, processing such as precision cutting in the manufacturing process is possible. Therefore, it becomes impossible to manufacture efficiently, and it takes a lot of time to manage the precision of the precise shape of the tip R (maintenance of quality), and it becomes impossible to reduce the manufacturing cost.
[0120]
Here, as for the film thickness after baking of a non-adhesive film, 5-30 micrometers is preferable. This is because the wear resistance is inferior in a thin film of 5 μm or less, and the tip R (curvature radius) of the separation claw may be larger than 10 to 60 μm in a thick film exceeding 30 μm.
[0121]
By measuring the contact angle of water or acetic acid water droplets on the surface of such a resin film, the non-stickiness of the surface can be determined. For example, if the contact angle of water droplets is 80 to 120 °, it is considered that the surface state of the resin film having sufficient non-adhesiveness in the present invention, and a more preferable contact angle is 90 to 120 °, particularly a paper passing test. Before, it is 100-120 degrees.
[0122]
Incidentally, the contact angle is measured using a goniometer-type contact angle tester manufactured by Elma Optical Co., Ltd., and 0.01 to 0.1 milliliter droplets, preferably 0.05 milliliter water droplets at room temperature and normal pressure. A typical method is dropping on the surface of the test piece and measuring the contact angle for 1 minute (after 30 seconds and after 1 minute) immediately after dropping, but is not limited to such a measurement method.
[0123]
In addition, the angle in the vicinity of the tip end portion of the separation claw shown in FIGS. 1 to 4 in the present invention is not particularly limited. Hereinafter, it is preferably 30 ° or less, and the lower limit is a sharp angle of 5 to 10 ° or more. When the angle is a dull angle exceeding a predetermined range, the function of peeling the sheet member such as paper most necessary for the separation claw from the roller is impaired. When the angle is an acute angle less than the predetermined range, the thickness around the tip of the separation claw becomes too thin and the paper is caught on the tip of the separation claw. Defects such as excessive force acting will occur.
[0124]
In addition, if the cutting edge width (plate material thickness) of the separation claw is 0.5 to 5 mm, preferably 1 to 3 mm, the claw tip has practical strength, and damage to the surface of the opposing roller is minimized. It is thought that it can be suppressed.
[0125]
In addition, the separation claw has a sheet passing surface and a shaft or a shaft hole for supporting the separation claw formed on the surface thereof. Since these are surfaces that are in sliding contact with other parts, their surface shape and surface roughness. Should be small. Similarly, a smaller surface roughness of the separation claw cavity portion of the injection mold is better for mold release.
[0126]
Such surface shape / surface roughness is measured by JIS-defined evaluation methods such as Rmax (maximum roughness), Ra (arithmetic average roughness), Rz (ten-point average roughness), etc. It forms in the range of 0.1-25 micrometers. An Rmax of less than 0.1 μm is not preferable because precise cutting is required and the production efficiency is extremely lowered. An Rmax of more than 25 μm causes many scratches on the sliding surface, resulting in wear. It also contributes.
[0127]
The surface roughness also has an influence on the shape of the surface of the coating applied to the surface being affected by the shape of the base. If the surface of the primer is smooth, the surface of the non-adhesive coating also becomes smooth. If the surface roughness of the separation claw cavity portion of the injection mold exceeds 25 μm, the releasability is lowered, yield and manufacturing efficiency are lowered, and practicality is lost. From such a tendency, more preferable Rmax is 1 to 10 μm, and further preferably 1 to 3.2 μm.
[0128]
The surface shape and surface roughness as described above are also required in the same manner for the paper passing surface portion of the separation claw coated with the fluororesin in the present invention. If the shaft or the shaft hole that supports the separation claw is difficult to wear depending on the specifications and use conditions of the separation claw, each of the above-described surface roughnesses may be in the range of about 3 to 8 μm in Rmax. As for the surface roughness, it is considered that if the surface of the coated film is also in the same range as described above (for example, Rmax. 0.1 to 25 μm), the toner adhesion amount can be reduced.
[0129]
The use of the separation claw in the present invention is not particularly limited. For example, a recording pattern is formed on a medium such as a photosensitive member by an electric signal given from the outside, and the electric quantity pattern formed on the medium is formed. Of course, the present invention can also be applied to a printer that employs various methods for converting an image into a visible pattern. Examples of such a printer system include an electrophotographic system, a thermal system, an optical printer system, an electronic recording system, and the like, and an electrophotographic apparatus is suitable for the use of the separation claw in the present invention.
[0130]
The types of electrophotography include the Carlson method, light / charge injection method, photopolarization method, photovoltaic method, charge transfer method, electroelectrophotography, electrostatic latent image photography, photoelectrophoresis, thermoplastic method Is mentioned. Examples of the optical printer include a laser printer, an LED (light emitting diode) printer, a liquid crystal shutter printer, and a CRT printer. Further, examples of the electronic recording method include an electrostatic recording method, an energization recording method, an electrolytic recording method, and a discharge recording method, and further include a direct method and an indirect method. In addition, there are methods such as a wet method and a dry method in which oil or the like is applied by these electrostatic recording methods.
[0131]
Specific apparatuses adopting the above system include toner image transfer type wet electrostatic copying machines, dry electrostatic copying machines (PPC), laser beam printers (LBP), liquid crystal shutter (LCD) printers, and facsimile machines. A printer, a light emitting diode (LED), a silver salt photographic printer (CRT), a printer, and other known image forming apparatuses.
[0132]
In addition, the mounting portion of the separation claw device of the present invention is a photosensitive portion, a developing portion, a fixing portion, and the like, and is not particularly limited, but particularly if the excellent heat resistance of a predetermined fluororesin is applied. The present invention can be applied to a fixing unit that is used under a higher temperature condition than the photosensitive unit and the developing unit. That is, the separation claw of the present invention is suitable for use in a fixing unit such as a fixing roller or a pressure roller disposed in the fixing device, and is preferably a roller facing the toner adhesion surface of the paper, that is, the fixing roller. This is suitable for a separation claw for a fixing roller of a dry electrostatic copying apparatus having a strict demand for toner adhesion. And this separation nail contacts with the static load of the grade which does not damage the other party roller, for example, contact pressure of 1-30 gf.
[0133]
【Example】
The raw materials used in Examples 1 to 6 and Comparative Examples 1 to 4 are collectively shown below. (1) Thermoplastic polyimide resin (with the structure represented by the formula 1 above; Mitsui East
Pressure Chemical Co., Ltd .: Aurum PD450)
(2) Titanium oxide whisker (pH 7); with body length average value of 1.68 μm and fiber diameter of 0.13 μm as measured by an image analyzer (Ishihara Sangyo Co., Ltd .: FTL100)
(3) Magnesium sulfate whisker (pH 9.5)
(Ube Industries, Ltd .: Mosheidi)
(4) FEP (average particle size pulverized to 0.5 μm; manufactured by Daikin Industries, Ltd .: NEOFLON FEP)
(5) FEP (average particle size pulverized to 20 μm; manufactured by Daikin Industries, Ltd .: NEOFLON FEP)
(6) Polyamideimide resin (average pulverized to 5 μm or less; manufactured by Hitachi Chemical Co., Ltd .: HI-400)
(7) Polyamideimide resin (average pulverized to about 25 μm; manufactured by Hitachi Chemical Co., Ltd .: HI-400)
(8) Polyimide resin precursor (one pulverized to an average particle size of 5 μm or less; manufactured by Toray Industries, Inc .: Torenice 2000)
(9) PFA (average particle size pulverized to 0.5 μm; manufactured by Daikin Industries, Ltd .: NEOFLON PFA)
(10) PFA (average particle size pulverized to 20 μm; manufactured by Daikin Industries, Ltd .: NEOFLON PFA)
(11) PTFE (pulverized to an average particle diameter of 5 μm; manufactured by Kitamura Co., Ltd .: KT400H) The average particle diameter is determined by using a laser diffraction particle size analyzer (manufactured by Nikkiso Co., Ltd .: Microtrac HRA). Asked.
[0134]
[Example 1]
30 parts by weight of titanium oxide whisker was blended with 100 parts by weight of the polyimide resin having the molecular structure represented by Chemical Formula 1, and after dry mixing, pellets were granulated using a twin screw extruder. This pellet is molded with an injection molding machine at a molding pressure of 1500 kgf / cm. ² Then, a separation nail was obtained by injection molding at a mold temperature of 200 ° C. and a cylinder temperature of 350 to 420 ° C.
[0135]
[Comparative Example 1]
After blending 20 parts by weight of magnesium sulfate whisker with 100 parts by weight of the polyimide resin having the molecular structure represented by Chemical Formula 1 and dry mixing, an attempt was made to granulate pellets using a twin screw extruder. Because of the generation of gas, granulation was stopped. Since the granulated polyimide resin composition was not pelletized and could not be injection-molded, the subsequent work was stopped.
[0136]
[Example 2]
The spool, runner, and defective product generated in Example 1 were pulverized into pellets, and separation claws were produced under the same conditions. This operation was repeated 5 times, and pellets were granulated with the material regenerated 5 times. This pellet was mixed uniformly with virgin material (unused material) at 50% by weight, and a separation claw was formed under the above injection molding conditions.
[0137]
Example 3
The pellets made of the material regenerated 5 times obtained in Example 2 were mixed uniformly with a virgin material at 80% by weight, and a separation claw was molded under the injection molding conditions.
[0138]
[Comparative Example 2]
Using the pellets made of the material recycled 5 times obtained in Example 2, a separation claw made of 100% recycled material was produced under the injection molding conditions. Thereafter, heat treatment was performed at 280 ° C. for 5 hours.
[0139]
The shape of the separation claw was 3 mm thick and the tip radius of curvature R30 μm, and the same shape as the separation claw of the fixing device of the dry electrostatic copying machine.
[0140]
The characteristics of the separation nail substrate were examined by the following test using the separation nail (as it was in the injection-molded state, so-called “injection molded finish”), and the results are shown in Table 1.
[0141]
[Evaluation test of separation nail substrate]
(A) Impact resistance: Using the impact testing machine shown in FIG. 1, one end of the lever is rotatably supported, a separation claw is attached to the other end of the lever, and the cutting edge is against the tangent to the roller. The contact was made at an angle of about 10 °. At that time, the length from the support portion (fulcrum) of the lever to the blade edge was 85 mm, and the static load of the blade edge was 20 gf. Then, the roller is heated to 250 ° C. by an internal heater, the lever is dropped from the upright state indicated by the chain line in FIG. 1, the blade edge is made to collide with the roller surface, and the number of collisions (maximum 10) Until times).
[0142]
(B) Fatigue resistance: Using the fatigue testing machine shown in FIG. 2, one end of the lever is rotatably supported, a separation claw is attached to the other end of the lever, and the cutting edge is against the tangent to the roller The contact was made at an angle of about 10 °. At that time, the length from the support portion (fulcrum) of the lever to the blade edge was 85 mm, and the static load of the blade edge was 20 gf. Then, a cam having an outer shape shown in the figure is provided below the middle of the lever, and this cam is rotated so that the cutting edge of the separation claw is intermittently collided from a height of 1 mm on the roller surface. The roller was heated to 250 ° C. by an internal heater and collided 100,000 times, and then the deformation (t): μm of the blade edge shown in FIG. 3 was examined.
[0143]
[Table 1]

[0144]
As is apparent from the results shown in Table 1, Comparative Example 2 composed of 100% recycled material was inferior in impact resistance and fatigue resistance. This result is considered to be because the reinforcement of the whisker is lost because the whisker is crushed when the pellet is regenerated. Moreover, the comparative example 1 which mix | blended the whisker of the alkali side from pH 9 was not able to granulate a pellet.
[0145]
[Examples 4 to 6, Comparative Examples 3 and 4]
A number of the same separation claws as in Example 2 were formed, the tip R was measured using a projector, and those having a tip R of 30 μm were selected. A primer solution and a non-adhesive coating solution prepared as described below were applied to the surface of the separated separation claw of the predetermined tip R in the combination shown in Table 2 and applied by the method described later.
(1) Primer solution 1: 100 parts by weight of FEP having an average particle size of 0.5 μm and polyamide having an average particle size of 5 μm or less Imide (PAI) 100 parts by weight of the resin was uniformly mixed, and 25 parts by weight was blended and dispersed in 100 parts by weight of pure water containing 20% by weight of NMP and 5% by weight of xylene.
[0146]
(2) Primer solution 2: 100 parts by weight of FEP having an average particle diameter of 0.5 μm and 500 parts by weight of a polyimide precursor having an average particle diameter of 5 μm or less are uniformly mixed to obtain 100 pure water containing 20% by weight of NMP and 5% by weight of xylene. 25 parts by weight was blended and dispersed with respect to parts by weight.
[0147]
(3) Primer solution 3: 100 parts by weight of FEP having an average particle diameter of 20 μm and 300 parts by weight of polyamide resin having an average particle diameter of 25 μm are uniformly mixed, and 100 parts by weight of pure water containing 20% by weight of NMP and 5% by weight of xylene. 25 parts by weight were mixed and dispersed.
[0148]
(4) Primer solution 4: 100 parts by weight of PFA having an average particle diameter of 0.5 μm and 300 parts by weight of a polyamide resin having an average particle diameter of 5 μm or less are uniformly mixed, and 100% by weight of pure water containing 20% by weight of NMP and 5% by weight of xylene 25 parts by weight were mixed and dispersed with respect to parts.
[0149]
[Non-tacky coating solution 1]
25 parts by weight of PFA having an average particle diameter of 20 μm was blended and dispersed in 100 parts by weight of pure water containing 20% by weight of NMP and 5% by weight of xylene.
[0150]
[Non-tacky coating solution 2]
To 100 parts by weight of pure water containing 20% by weight of NMP and 5% by weight of xylene, 25 parts by weight of PFA having an average particle diameter of 20 μm and 20 parts by weight of PTFE having an average particle diameter of about 5 μm were blended and dispersed.
[0151]
When coating the primer solution and the non-adhesive coating solution prepared as described above, using a spray gun with a nozzle diameter of 1 mm, the separation nail is moved back and forth toward the paper passing surface and the tip R of the separation nail. A predetermined coating solution was applied to the substrate. The moving speed was set to 50 to 300 mm / sec so that the speed unevenness during continuous moving for 1 second or more was within ± 10%. This is because the coating liquid tends to sag at a low speed of less than 50 mm / second, and a wet surface is difficult to form at a high speed of over 300 mm / second. Moreover, the atomizing discharge pressure of the spray gun is 3 to 6 kgf / cm. ² Set to.
[0152]
The spraying distance was set such that the distance between the surface to be coated and the nozzle tip was 150 to 250 mm. At short distances of less than 150 mm, the coating liquid accumulates on the surface to be coated, and uneven coating tends to occur. At long distances above 250 mm, the mist-like coating liquid particles dries before the coating liquid sufficiently adheres to the surface to be coated. This is because the surface roughness of the painted surface increases.
[0153]
As described above, the primer solution was applied to the surface of the separation nail by spray coating and dried in a drying furnace at an atmospheric temperature of 80 ° C. for 20 minutes to completely evaporate the solvent contained in the primer solution. Thereafter, a coating solution for a non-adhesive coating was further applied by spray coating over the primer layer, and the temperature was raised stepwise to 350 ° C. and held for 30 minutes. The total firing time in this case was 12 hours.
Then, it was allowed to stand and gradually cooled to room temperature, and a separation nail having a non-adhesive coating coated on the surface of the separation nail via a primer layer was produced.
[0154]
[Table 2]

[0155]
For each of 30 separation claws of Examples 4 to 6 and Comparative Examples 3 and 4 in which a non-adhesive film was formed through a primer with the combination shown in Table 2, the projection R was uneven. Table 2 shows the maximum value, minimum value, average value, and standard deviation.
[0156]
Further, among the separation claws of Examples 4 to 6 and Comparative Examples 3 and 4, three each having a tip R of 45 μm were selected and attacked against the sliding contact roller using the wear tester shown in FIG. In addition, the following tests were conducted under the conditions in conformity with the specifications of the fixing device of the dry electrostatic copying apparatus, and the results are shown in Table 3.
[0157]
1. Opposition of opponent's roller
Each test piece (with a separation claw tip R of 45 μm, three each) was mounted on the wear tester shown in FIG. That is, one end of the lever of the wear tester is rotatably supported, and a separation claw is attached to the other end of the lever so that the blade edge contacts the tangent of the roller at an angle of about 10 °. . At that time, the length from the support portion (fulcrum) of the lever to the blade edge was 85 mm, and the static load of the blade edge was 20 gf.
[0158]
The other roller in contact with the separation claw is a roller of S45C φ50 mm pipe material coated with PFA with a thickness of 30 μm in the same manner as the fixing roller. A heater was installed in this pipe material to heat the roller surface to 250 ° C. . Then, with the blade tip in contact with the roller, the roller was rotated at a speed of 148 rpm, and after 400 hours, the damage of the PFA coating on the surface of the mating roller was observed. A thickness of 6 μm or more and less than 20 μm is indicated by Δ, and a damage depth of 20 μm or more is indicated by ×.
[0159]
2. Abrasion resistance
About the separation claw tested by the aggression property of the said partner roller, the state of the non-adhesive film of the blade edge | tip contact | abutted with the roller was investigated. The evaluation is based on the mark with the coating on the blade edge after completion of the test, the mark with the coating being worn and the primer layer being exposed, and the coating being worn and the substrate exposed. What was present was marked with x.
[0160]
[Table 3]

[0161]
From the results in Table 2, it can be seen that the separation claws of the examples have small variations in the film thickness and the quality is stable. Also, among the examples, Example 4, which employs PAI as the binder for the primer, is smaller in variation and thinner than Example 5 in which PI is employed as the binder, and has excellent peeling performance. It was quality.
[0162]
In Example 6 in which PTFE was added to the non-adhesive film, the variation in film thickness and tip R was slightly inferior to that in which PTFE was not added, but the wear resistance was excellent from the results in Table 3. It turns out that it is a thing.
[0163]
In contrast to these examples, Comparative Example 4 in which PFA was used as a primer and Comparative Example 3 in which the average particle size of the solid content of the primer exceeded the predetermined range had a large variation in film thickness. There was a tendency for the film thickness to become inappropriately large. Further, from the results of Table 3, it was also found that Comparative Example 3 having a larger average particle size of the primer than the predetermined range is aggressive against the mating roller.
[0164]
【The invention's effect】
In the present invention, as described above, since the main component of the primer is a tetrafluoroethylene-hexafluoropropylene copolymer and a binder resin, the tip of the separation claw is excellent in heat resistance with a very uniform thin layer. The cutting edge shape of the part has an advantage that it is possible to provide an extremely sharp and uniformly precise R-shaped separation claw of about R40 μm and a method for manufacturing the same.
[0165]
Further, the tip of the separation claw on which the fluororesin film is formed through the primer layer has the required sharp R shape, and the separation claw that can peel off 60-75 μm thin paper, which is a thinner copy paper than before, and its There is an advantage that a manufacturing method can be provided.
[0166]
Further, there is an advantage that a primer for coating a thin film fluororesin necessary for producing the separation claw having a good peeling performance can be provided.
[Brief description of the drawings]
FIG. 1 is a schematic side view of an impact tester.
FIG. 2 is a schematic side view of a fatigue resistance tester.
FIG. 3 is an explanatory diagram of the deformation amount of the cutting edge of the separation claw
FIG. 4 is a schematic side view of a testing machine for attacking resistance and wear resistance of a mating roller

Claims (4)

  A polyamideimide resin having an average particle size of 0.3 to 5 μm, a polyimide resin, and a polyimide resin, and at least a cutting edge surface of a separation nail base material composed of a thermoplastic polyimide resin as a main component and containing a whisker having a pH of 9 or less A primer layer containing one or more resins selected from the group consisting of precursors and a tetrafluoroethylene-hexafluoropropylene copolymer having an average particle diameter of 0.1 to 10 μm is provided, and a perfluoroalkyl vinyl ether copolymer is provided thereon. Separation nail formed by baking and coating a continuous film mainly composed of a polymer.   The separation nail according to claim 1, wherein the film is a film in which 0.1 to 30% by weight of polytetrafluoroethylene powder is blended with a perfluoroalkyl vinyl ether copolymer.   The separation nail according to claim 1 or 2, wherein the thermoplastic polyimide resin is a thermoplastic polyimide resin containing 80% by weight or less of a recycled thermoplastic polyimide resin.   A polyamideimide resin having an average particle size of 0.3 to 5 μm, a polyimide resin, and a polyimide resin, and at least a cutting edge surface of a separation nail base material composed of a thermoplastic polyimide resin as a main component and containing a whisker having a pH of 9 or less A primer solution containing one or more resins selected from the group consisting of precursors and a tetrafluoroethylene-hexafluoropropylene copolymer having an average particle size of 0.1 to 10 μm is applied and dried, and then perfluoro A method for producing a separation nail comprising applying a solution containing an alkyl vinyl ether copolymer as a main component and drying, followed by baking at 340 to 380 ° C. to form a non-adhesive continuous film on the surface of the separation nail .

Images