JP3873488B2 - Low hardness conductive roll manufacturing method - Google Patents

Description

【００２９】
上記一般式（１）において、Ｒ¹ 、Ｒ² で表される炭素数１〜２０のアルキレン基としては、例えば、メチレン基、エチレン基、プロピレン基、ブチレン基、ヘキシレン基、オクチレン基、ドデシレン基等があげられる。また、上記一般式（１）における繰り返し数ｎは、上記ポリジメチルシロキサンジカルビノールの分子量が５００〜１００００の範囲になるような正数が選ばれ、好ましくは上記分子量が１０００〜６０００の範囲になるような正数が選ばれる。
【００３０】
上記シリコーン変性ウレタンとしては、上記一般式（１）におけるメチル基の少なくとも一部を特定の置換基で置換した化合物を用いることもできる。上記特定の置換基としては、例えば、炭素数２〜３０のアルキル基、ハロアルキル基、シアノアルキル基、アリルアルキル基、ビニル基、アクリル基等のアルケニル基、アリル基、アルキルアリル基、アルケニルアリル基、ハロアリル基、水素原子、ハロゲン原子等があげられる。これらは単独でもしくは二種以上併せて用いられる。
【００３１】
上記シリコーン変性ウレタンは、例えばつぎのようにして作製することができる。すなわち、上記特殊な化合物（Ａ）と、二官能性イソシアネートとを所定の配合割合で配合し、ジブチル錫ジラウレート（ＤＢＴＤＬ）等の従来公知のウレタン化触媒の存在下で反応を行い（反応条件：８０〜１２０℃×１〜５時間）、粘度の安定したところで取り出すことによって、直鎖状プレポリマーを作製し、さらに必要に応じて鎖延長剤やポリオールを添加して反応を行い（反応条件：８０〜１２０℃×１〜５時間）、これを溶剤に溶解することによって作製することができる。
【００３２】
さらに、前記シリコーングラフトアクリルポリマーは、下記の一般式（２）で表される構造を備えたものである。
【００３３】
【化２】

【００３４】
上記一般式（２）において、繰り返し数ｋは１〜３０００の正数であり、好ましくは１〜３００の正数である。また、繰り返し数ｎは１〜３０００の正数であり、好ましくは１〜３００の正数である。
【００３５】
上記一般式（２）において、Ｙはアクリル系単量体から誘導される直鎖状の構造部分である。上記アクリル系単量体としては、具体的には、アクリル酸、アクリル酸メチル、アクリル酸エチル、アクリル酸オクチル、アクリル酸ドデシル、アクリル酸２−エチルヘキシル、アクリル酸プロピル、アクリル酸ｎ−ブチル、アクリル酸イソブチル、アクリル酸ｓｅｃ−ブチル、アクリル酸ｔｅｒｔ−ブチル、アクリル酸２，２−ジメチルプロピル、アクリル酸シクロヘキシル、アクリル酸−２−ｔｅｒｔ−ブチルフェニル、アクリル酸２−ナフチル、アクリル酸フェニル、アクリル酸４−メトキシフェニル、アクリル酸２−メトキシカルボニルフェニル、アクリル酸２−エトキシカルボニルフェニル、アクリル酸２−クロロフェニル、アクリル酸４−クロロフェニル、アクリル酸ベンジル、アクリル酸２−シアノベンジル、アクリル酸４−シアノフェニル、アクリル酸ｐ−トリル、アクリル酸イソノニル、アクリル酸２−ヒドロキシエチル、アクリル酸２−ヒドロキシプロピル、アクリル酸２−ヒドロキシブチル、アクリル酸２−シアノエチル、アクリル酸３−オキサブチル、アクリルアミド、メタクリル酸、メタクリル酸メチル、メタクリル酸エチル、メタクリル酸オクチル、メタクリル酸ドデシル、メタクリル酸２−エチルヘキシル、メタクリル酸プロピル、メタクリル酸ｎ−ブチル、メタクリル酸イソブチル、メタクリル酸ｓｅｃ−ブチル、メタクリル酸ｔｅｒｔ−ブチル、メタクリル酸２，２−ジメチルプロピル、メタクリル酸シクロヘキシル、メタクリル酸−２−ｔｅｒｔ−ブチルフェニル、メタクリル酸２−ナフチル、メタクリル酸フェニル、メタクリル酸４−メトキシフェニル、メタクリル酸２−メトキシカルボニルフェニル、メタクリル酸２−エトキシカルボニルフェニル、メタクリル酸２−クロロフェニル、メタクリル酸４−クロロフェニル、メタクリル酸ベンジル、メタクリル酸２−シアノベンジル、メタクリル酸４−シアノフェニル、メタクリル酸ｐ−トリル、メタクリル酸イソノニル、メタクリル酸２−ヒドロキシエチル、メタクリル酸２−ヒドロキシプロピル、メタクリル酸２−ヒドロキシブチル、メタクリル酸２−シアノエチル、メタクリル酸３−オキサブチル、γ−メタクリロイルオキシプロピルトリメトキシシラン、アクリルアミド、ブチルアクリルアミド、Ｎ，Ｎ−ジメチルアクリルアミド、ピペリジルアクリルアミド、メタクリルアミド、４−カルボキシフェニルメタクリルアミド、４−メトキシカルボキシフェニルメタクリルアミド、メチルクロロアクリレート、エチル−α−クロロアクリレート、プロピル−α−クロロアクリレート、イソプロピル−α−クロロアクリレート、メチル−α−フルオロアクリレート、ブチル−α−ブトキシカルボニルメタクリレート、ブチル−α−シアノアクリレート、メチル−α−フェニルアクリレート、イソボニルアクリレート、イソボニルメタクリレート、ジエチルアミノエチルメタクリレート等があげられる。そして、これらアクリル系単量体の一種が重合または二種以上が共重合することにより、Ｙで表される直鎖状の構造部分が構成される。
【００３６】
上記一般式（２）において、Ｚはアクリル系単量体から誘導される構造部分であって、シロキサンから誘導される構造部分を側鎖に有するものである。これは、下記の一般式（３）または一般式（４）で表されるものから誘導される。
【００３７】
【化３】

【００３８】
【化４】

【００３９】
そして、上記一般式（３）または一般式（４）の好ましい具体例としては、下記の構造式（Ｚ−１）〜（Ｚ−１８）に示すものがあげられる。
【００４０】
【化５】

【００４１】
【化６】

【００４２】
【化７】

【００４３】
【化８】

【００４４】
そして、上記一般式（２）で表される構造を備えたシリコーングラフトアクリルポリマーは、例えば、つぎのようにして製造することができる。すなわち、上記（Ｙ）_k 部分と（Ｚ）_n 部分を、アゾビスイソブチロニトリル（ＡＩＢＮ）等のアゾ系重合開始剤の存在下に、ラジカル重合（重合条件：５０〜１５０℃×３〜１００時間）させることにより、製造することができる。このような重合は、溶媒を用いる溶液重合法、バルク重合法、エマルジョン重合法等によって行うことができ、なかでも溶液重合法によるのが特に好ましい。
【００４５】
なお、シリコーングラフトアクリルポリマーとしては、前記一般式（２）で表される構造を備えたものであるが、この構造にさらにアクリル系単量体から誘導される直鎖状の構造部分が連結された、下記の一般式（５）で表される構造を備えたものであってもよい。
【００４６】
【化９】

【００４７】
上記一般式（５）において、Ｘは、アクリル系単量体から誘導される直鎖状の構造部分である。そして、上記アクリル系単量体としては、前記一般式（２）において例示したものと同様のものがあげられる。ただし、ＹとＸは、互いに異なるものでなければならない。
【００４８】
上記一般式（５）において、繰り返し数ｎは、１〜３０００の正数であり、好ましくは、１〜３００の正数である。
【００４９】
なお、上記シリコーングラフトアクリルポリマーは、上記のようにして作製すことができるが、市販品を用いてもよい。このようなものとしては、例えば、サイマックＵＳ２７０（東亜合成社製）、Ｘ−２２−８００４（信越化学社製）が知られている。
【００５０】
また、前記アクリルポリオールは、下記の一般式（６）で表される構造を備えたものである。
【００５１】
【化１０】

【００５２】
上記一般式（６）において、繰り返し数ｋは１〜３０００の正数であり、好ましくは１〜３００の正数である。また、繰り返し数ｎは１〜３０００の正数であり、好ましくは１〜３００の正数である。
【００５３】
上記一般式（６）において、Ｙはアクリル系単量体から誘導される直鎖状の構造部分である。このようなアクリル系単量体としては、前述と同様のものがあげられる。そして、これらアクリル系単量体の１種が重合または２種以上が共重合することにより、Ｙで表される直鎖状の構造部分が構成される。
【００５４】
上記一般式（６）において、Ｗはアクリル系単量体から誘導される構造部分であって、活性水素基を有するものである。これは、前述と同様のアクリル系単量体から誘導される。また、二官能性イソシアネート、鎖延長剤等で反応させ高分子化したものを用いてもよい。
【００５５】
なお、上記アクリルポリオールは、上記のようにして作製することができるが、市販品を用いてもよい。このようなものとしては、サンプレンＩＢ（三洋化成社製）、ＳＫダインＡＧ１０５（綜研化学社製）が知られている。
【００５６】
本発明において、上記溶剤可溶性ポリマー〔（ａ）成分〕とともに用いられるブロックイソシアネート〔（ｂ）成分〕としては、ポリイソシアネートと、ブロック剤とを反応させることにより得られるものがあげられる。このブロックイソシアネート〔（ｂ）成分〕は、単独で用いてもよいし、二種以上併せて用いてもよい。
【００５７】
上記ポリイソシアネートとしては、特に限定するものではないが、高温時において揮発性のないものが好ましい。具体的には、ヘキサメチレンジイソシアネート（ＨＭＤＩ）、トリレンジイソシアネート（ＴＤＩ）、ジフェニルメタンジイソシアネート（ＭＤＩ）、カルボジイミド変性ＭＤＩ、イソホロンジイソシアネート（ＩＰＤＩ）、クルードＭＤＩ等のイソシアネート化合物があげられる。また、これらイソシアネート化合物のアダクト体やビューレット体を用いることができる。さらに、これらイソシアネート化合物を用い、触媒の存在下で反応させて得られるイソシアヌレート環を有するイソシアヌレート体を用いることができる。なかでも、常温下において非常に安定であり、オーバーベーク時に黄変を生じない点から、イソシアヌレート体が好ましい。
【００５８】
上記ブロック剤としては、イソシアネート基をブロックできるものであって、ブロック後加熱することによりブロックが外れるという性質を有するものであれば特に限定するものではないが、揮発性のものであって、活性水素基含有化合物が好ましい。具体的には、２−エチルヘキサノール等のアルコール類や、フェノール、クレゾール、イソノニルフェノール等のフェノール類や、ε−カプロラクタムや、メチルエチルケトキシム等のオキシム類や、マロン酸ジエチル、アセト酢酸エチル等の活性メチレン化合物類があげられる。これらは、単独で用いてもよいし、二種以上併せて用いてもよい。
【００５９】
そして、上記ポリイソシアネートおよびブロック剤を用い、例えばつぎのようにしてブロックイソシアネート〔（ｂ）成分〕を作製することができる。すなわち、ポリイソシアネートに対し、略当量のブロック剤を、所定の温度（４０〜６０℃程度）に保持しながら、滴下することにより作製することができる。また、それ以外の方法としては、例えば、イソシアヌレート体を作製する場合、上記イソシアネート化合物に対し、当量の略半分の量のブロック剤を、所定の温度（４０〜６０℃程度）に保持しながら、滴下してハーフブロック体を作製する。ついで、オクチル酸カリウム、セロソルブアセテート等を加えてイソシアヌレート化させることにより作製することができる。上記それ以外の方法を用いてブロックイソシアネートを作製した場合には、より反応性の高いイソシアネート基をブロックし、比較的反応性の低いイソシアネート基をイソシアヌレート結合に供することができる。このため、溶剤可溶性ポリマー〔（ａ）成分〕の活性水素基のブロックをより効率良く行うことができる。
【００６０】
なお、上記ブロックイソシアネート〔（ｂ）成分〕は、上記のように、ポリイソシアネートおよびブロック剤を反応させて得ることができるが、市販品を用いてもよい。このようなものとしては、例えば、コロネート２５１３（日本ポリウレタン社製）、バーノックＤ５５０、バーノックＤ５００、バーノックＢ８−１１７、バーノックＤＢ９８０ｋ（４つとも大日本インキ社製）が知られている。なお、上記バーノックＤＢ９８０ｋは、下記の化学式（７）に従って得られるものである。
【００６１】
【化１１】

【００６２】
上記表面層形成材料には、溶剤可溶性ポリマー〔（ａ）成分〕およびブロックイソシアネート〔（ｂ）成分〕以外に、ブロックイソシアネート〔（ｂ）成分〕のブロックを外しやすくする目的で、解離触媒を配合してもよい。この解離触媒を用いると、ロールの製造工程における加熱処理の温度を低減することができる。上記解離触媒としては、１，３−ジアセトキシテトラブチルスタノキサン、ジブチル錫ジラウレート等の錫系化合物や、Ｎ−メチルモルホリン等の３級アミン等があげられる。
【００６３】
上記表面層形成材料には、適正な体積電気抵抗（１０⁵ 〜１０¹¹Ω・ｃｍ）を付与することを目的として、導電剤を配合する。この体積電気抵抗にかかる特性は、例えば、現像ロールの表面層の特性として重要である。上記導電剤としては、ｃ−ＴｉＯ₂ 、ｃ−ＺｎＯ、ケッチェンブラック、アセチレンブラック等のカーボンブラック、ｃ−ＳｎＯ₂ 、酸化鉄、グラファイト、チタン酸カリウム、四級アンモニウム塩、ホウ酸塩、リチウム塩等があげられる。これらは単独でもしくは二種以上併せて用いられる。なかでも、適正な体積電気抵抗を得ることができるという理由から、ｃ−ＴｉＯ₂ 、ｃ−ＺｎＯ、アセチレンブラック、四級アンモニウム塩を用いることが好ましい。なお、上記「ｃ−」とは導電性を有することを意味する。
【００６４】
そして、上記表面層形成材料には、上記以外に、帯電制御剤、充填剤、安定剤、紫外線吸収剤、帯電防止剤、補強剤、滑剤、離型剤、染料、顔料、難燃剤、オイル等を必要に応じて適宜に配合することができる。
【００６５】
上記表面層形成材料とともに用いる溶剤としては、テトラヒドロフラン（ＴＨＦ）、メチルエチルケトン（ＭＥＫ）、メチルイソブチルケトン（ＭＩＢＫ）、トルエン、酢酸エチル等があげられる。
【００６６】
そして、上記表面層形成材料および溶剤を用い、つぎのようにして表面層形成用溶液を作製する。すなわち、上記溶剤可溶性ポリマー〔（ａ）成分〕とブロックイソシアネート〔（ｂ）成分〕を、ＮＣＯ／活性水素比が、当量比で、２．５〜３５の範囲内となるよう溶剤中に配合するともに導電剤を配合し、必要に応じて解離触媒等を配合することにより作製することができる。上記ＮＣＯ／活性水素比のより好適な範囲は、５〜１５である。すなわち、ＮＣＯ／活性水素比が２．５未満であると、イソシアネート基が少なすぎて、活性水素基を充分に低減することができないからであり、ＮＣＯ／活性水素比が３５を越えると、得られるロールの表面が硬くなって、基体の低硬度化を損ない、トルク負荷が増大するからである。なお、上記ＮＣＯ／活性水素比の算出は、上記ブロックイソシアネート〔（ｂ）成分〕のブロックが外れているものとして行う。
【００６７】
本発明において、上記ロール基体および表面層形成用溶液を用い、例えばつぎのようにしてロールを製造する。すなわち、まず、前述した方法に従い、ロール基体および表面層形成用溶液を準備する。ついで、上記ロール基体の外周面に、表面層形成用溶液を、ディッピング法、ロールコート法等の従来公知の方法により塗工して液膜を形成する。そして、塗工後、所定の温度で加熱処理することにより、液膜中の溶剤が揮散して表面層が形成されるとともに、ブロックイソシアネート〔（ｂ）成分〕におけるイソシアネート基のブロックが外れ、露出したイソシアネート基が、溶剤可溶性ポリマー〔（ａ）成分〕の活性水素基と反応して、架橋するようになる。このようにして、図２に示す、ロール基体１６の外周面に、表面層１７が形成されたロール１８を作製することができる。
【００６８】
上記製法において、加熱処理の温度は、１３０〜２５０℃の範囲に設定されていることが好ましい。より好ましくは、１５０〜２００℃の範囲である。すなわち、加熱処理の温度が、１３０℃未満であると、ブロックイソシアネート〔（ｂ）成分〕のブロックが外れないおそれがあるからである。逆に、加熱処理の温度が２５０℃を越えると、ロール基体や表面層のポリマーが分解するおそれがあるからである。
【００６９】
上記製法によれば、活性水素基を効果的に低減できるため、トナーフィルミングを生じないロール１８を得ることができる。また、活性水素基の低減にあたり、ブロック剤が外れたポリイソシアネートは、いわば架橋剤の働きをするため、表面層１７に対してタック性を低減でき、耐久性に優れたロール１８を得ることができる。さらに、活性水素基のブロックにあたり、ブロックイソシアネート〔（ｂ）成分〕を用いるため、ロール製造時の表面層形成用溶液の保存性を良好にすることができる。
【００７０】
このようにして得られたロール１８において、各層の厚みは、適宜に決定されるが、例えば、現像ロールの用途に用いる場合には、最内層の厚みは、０．５〜１０ｍｍの範囲に決定することが好ましく、より好ましくは３〜６ｍｍである。また、中間層の厚みは、１〜９０μｍの範囲に設定することが好ましく、より好ましくは３〜１５μｍである。そして、表面層の厚みは５〜１００μｍの範囲に設定することが好ましく、より好ましくは５〜３０μｍである。
【００７１】
なお、本発明において、上記ブロックイソシアネート〔（ｂ）成分〕に代えて、ポリイソシアネート〔（ｂ′）成分〕を用いてもよい。このポリイソシアネート〔（ｂ′）成分〕としては、ジフェニルメタンジイソシアネート（ＭＤＩ）、イソホロンジイソシアネート（ＩＰＤＩ）、ジシクロヘキシルメタンジイソシアネート（水添ＭＤＩ）、トリメチルヘキサメチレンジイソシアネート（ＴＭＨＤＩ）、トリレンジイソシアネート（ＴＤＩ）、カルボジイミド変性ＭＤＩ、ポリメチレンフェニルポリイソシアネート（ＰＡＰＩ）、オルトトルイジンジイソシアネート（ＴＯＤＩ）、ナフチレンジイソシアネート（ＮＤＩ）、キシレンジイソシアネート（ＸＤＩ）、ヘキサメチレンジイソシアネート（ＨＭＤＩ）、パラフェニレンジイソシアネート（ＰＤＩ）、リジンジイソシアネートメチルエステル（ＬＤＩ）、ジメチルジイソシアネート（ＤＤＩ）等のイソシアネート化合物があげられる。また、これらのイソシアネート化合物のアダクト体やビューレット体を用いることができる。さらに、これらイソシアネート化合物を用い、触媒の存在下で反応させて得られるイソシアヌレート環を有するイソシアヌレート体を用いることができる。なかでも、常温下において非常に安定であり、オーバーべーク時に黄変を生じない点から、イソシアヌレート体が好ましい。さらには、上記溶剤可溶性ポリマー〔（ａ）成分〕との混合の際に、激しく反応せず、製造上問題がないという観点から、ＴＤＩのＴＭＰアダクト体、ＨＤＩのイソシアヌレート体が好ましい。そして、このポリイソシアネート〔（ｂ′）成分〕を用いた場合には、ブロックを外すという操作が不要なため、ロールを効率良く得ることができるという利点を有する。
【００７２】
本発明のロールは、給紙ロール、帯電ロール、現像ロール、転写ロール、定着ロール等として用いることができ、特に現像ロールとして用いることが好適である。
【００７３】
つぎに、実施例について比較例と併せて説明する。
【００７４】
〔ロール基体の作製〕
まず、実施例および比較例に先立ち、軸体の外周に最内層を有し、この最内層の外周に中間層を有するロール基体を準備した。すなわち、軸体となる芯金（直径１０ｍｍ、ＳＵＳ３０４製）と、最内層形成材料として液状シリコーンゴムにカーボンブラックを添加したものと、中間層形成材料として水素化ニトリルゴムにカーボンブラックを添加したものとを準備し、前述の方法に準じて、軸体の外周面に、最内層（厚み：５ｍｍ）を形成し、さらにその外周面に中間層（厚み：１０μｍ）を形成した。なお、このロール基体のＪＩＳ Ａ硬度は、３０°であった。
【００７５】
【実施例１〜１０】
下記の表１に示す溶剤可溶性ポリマーおよび下記の表２に示す硬化剤を準備した。つぎに、下記の表３および表４に示す各成分を同表に示す配合割合で配合して、表面層形成用溶液を作製した。つぎに、この表面層形成用溶液を、上記ロール基体の外周面に前述の方法（ディッピング法）に従い塗布した後、同表に示す条件で加熱処理して表面層（厚み：１５μｍ）を形成し、目的とする現像ロールを作製した。
【００７６】
【表１】

【００７７】
【表２】

【００７８】
【表３】

【００７９】
【表４】

【００８０】
【比較例１】
特開平５−３１３４８３号公報に準じて現像ロールを作製した。具体的には、以下の手順に従って作製した。
【００８１】
〔ロールの製法〕
ポリエステルポリオール（クラポールＰ−２０１０、クラレ社製）１００重量部に、過塩素酸リチウムを０．０５重量部加え、攪拌し溶解させた後、１００℃に温調し、ついでコロネートＨＸ（日本ポリウレタン社製）２０重量部およびアルコール変性シリコーンオイル（ＳＦ−８４２７、東レ・ダウコーニング社製）２０重量部を添加、攪拌し、混合物を得た。この混合物を、予め軸体が配置されている１２０℃に予熱された金型に注入し、１２０℃にて６０分間加熱し、両端部を除く軸体の表面に導電性ポリウレタン弾性体層が形成されたロール基体を得た。
【００８２】
〔表面処理液の調製〕
ＭＲ４００（日本ポリウレタン社製）１００重量部を、酢酸エチル９００重量部に溶解させ、表面処理液を得た。
【００８３】
〔ロール基体表面処理〕
前記溶液を２０℃に保ったまま、前記ロール基体を所定時間浸漬後、１００℃に保持されたオーブンで１０時間加熱することにより現像ロールを得た。
【００８４】
【比較例２】
特開平８−２７２２１１号公報に準じて現像ロールを作製した。すなわち、官能基数３、分子量５０００のポリエーテルポリールにＮＣＯ％が６．７になるようにトリレンジイソシアネートを反応させて得られたプレポリマー１００重量部に、１，４−ブタンジオール６．５５重量部、シリコーン界面活性剤２重量部、ジブチルチンジラウレート０．０１重量部およびアセチレンブラック２．０重量部を添加し、混合機を用いて２分攪拌した後、予め軸体をセットし、６０℃に予熱されたモールドに反応混合液を注入し、６０℃で１２時間キュアした。脱型後研磨し、外層がウレタンフォームのロール基体を得た。ついで、官能基数２．３５、分子量２８００のポリイソプレンポリオール１００重量部を真空で３０分減圧脱泡した後、ＮＣＯ％が３１．７の粗製ジフェニルメタン−４，４′ジイソシアネート１２．７重量部、ジブチルチンジラウレート０．０１重量部およびアセチレンブラック３．５重量部を添加し、再度減圧脱泡しつつ３分間攪拌した後、予め上記で得られたロール基体がセットされ、９０℃に予熱したモールドに流し込み、９０℃で１６時間キュアを行い、脱型した後、研磨した。このようにして、疎水性ウレタンエラストマーを最外層とし、内部がウレタンウォームである二層構造の現像ロールを得た。
【００８５】
【比較例３】
特開平９−１１４１９０号公報に準じて現像ロールを作製した。すなわち、まず、以下の手順に従ってポリウレタンエラストマーを調製した。
【００８６】
〔ポリオール成分の調製〕
ポリプロピレンポリオールＡ（住友バイエルウレタン社製）７５重量部と、ポリプロピレンポリオールＢ（住友バイエルウレタン社製）２５重量部と、カーボンブラック（ライオン・アクゾ社製）２重量部とをよく混合攪拌後、ロールで練った。つぎに、ＤＢＵ−フェノール塩（サンアプロ社製）０．２重量部と、ジブチル錫ジラウレート（日東化成社製）０．１重量部を、上記混合物中へ添加し、攪拌して触媒を分散させた。混合物が均一になった後、４０℃、３Ｔｏｒｒで３時間以上減圧脱水を行った。
【００８７】
〔プレポリマー化イソシアネートの調製〕
ポリプロピレンポリオールＣ（住友バイエルウレタン社製）２．８６重量部にＨＤＩ６．３３重量部を添加し、攪拌後、７０℃で２４時間窒素雰囲気下で反応させ末端ＮＣＯ基のプレポリマー化イソシアネートを得た。
【００８８】
〔ポリウレタンエラストマーの調製〕
上記ポリオール成分に、上記プレポリマー化イソシアネートで調製したプレポリマー化イソシアネートを、イソシアネートインデックスが１０５となるよう計量して添加した。添加時のプレポリマー化イソシアネートと、ポリオール成分の液温は、いずれも約４０℃であった。プレポリマー化イソシアネートを添加後、混合物をアジテータで攪拌した。
【００８９】
つぎに、外周に接着剤を塗布したステンレス製の軸体を、金型にセットし７０℃に保持した。この金型に前記混合物を注入して、約１０分間反応硬化させて、ポリウレタンエラストマーからなる導電弾性層を形成した。これを脱型し、室温で約２４時間熟成した。その後、この導電弾性層の表面を研磨機で研磨し、現像ロールを得た。
【００９０】
このようにして得られた各現像ロールについて、下記の方法に従って、硬度、電気抵抗、摩擦係数、ロール回転トルク、トナー帯電量、複写画像の画質評価、耐フィルミング性、耐久性の測定または評価を行い、その結果を後記の表５〜表７に示した。
【００９１】
〔硬度〕
ＪＩＳ Ａによる硬度を測定した。その結果、先に述べたように、その測定値が７０°以下であれば、本発明のロールにおける「低硬度」の範囲にある。
【００９２】
〔電気抵抗〕
図３に示す形状の電極１９を準備し、これをロール表面上に２０箇所設置した後、図４に示す測定系により測定した。図３において、１９ａは主電極、１９ｂはガード電極である。また、図４において、２０はロールである。なお、電気抵抗値は、２０箇所の測定値の中央値として示した。その結果、先に述べたように、その測定値が１０⁹ Ω以下であれば、本発明のロールにおける「導電性」の範囲にある。
【００９３】
〔摩擦係数〕
摩擦係数は、図５に示すような、静動摩擦係数計（協和界面化学社製）を用いて測定した。すなわち、厚み５０〜１００μｍの塗膜２１を作製し、これを固定台２２の上にセットし、移動速度０．３ｃｍ／秒、荷重１００ｇの条件下で測定した。なお、図において、２３は鋼球（直径３ｍｍ）、２４は零点調整用天秤、２５はロードセル、２６は荷重（１００ｇ）を示す。
【００９４】
〔ロール回転トルク〕
各現像ロールを固定された感光体に対して、接触部が径方向に０．３ｍｍ凹む程度の圧力で押圧接触させて、各ロールをトルクモータで回転させ、その動き始めの電流値をそれぞれ測定した。そして、得られた測定値をトルクに換算し、その算出値が３ｋｇｆ−ｃｍ未満の場合を○、３ｋｇｆ−ｃｍ以上の場合を×として表示した。
【００９５】
〔トナー帯電性〕
トナー帯電性は、現像ロールにおける帯電量を２０℃×５０％ＲＨの条件下においてつぎのようにして測定した。すなわち、図６に示すように、現像ロール３０表面上に現像剤（トナー）３２層を形成し、吸引ポンプ３３により現像剤３２を吸引しファラデーケージ３４により測定した（ファラデーケージ法）。なお、図において、３５はフィルター、３６は絶縁体パイプ、３７は電位計、３８，３９は導体で互いに分離している。なお、この測定値の絶対値が大きいほど、トナー帯電性が良好であるといえる。
【００９６】
〔複写画像の画質評価〕
複写初期および３０００枚複写後における複写画像の画質を目視により評価した。すなわち、文字を複写し、複写画像に問題がなく、細線が鮮明に複写されたものを○、かすれやかぶり等が発生したものを×としてそれぞれ表示した。なお、かすれとは細線がとぎれたものをいい、かぶりとはイメージのないところにトナーが飛んでいるものをいう。
【００９７】
〔耐フィルミング性〕
現像ロール表面に現像剤（トナー）が厚く付着した部分は、帯電性が悪くなり複写画像に不良を生じる。具体的には、現像ロール表面に現像剤の一部が１μｍ以上の厚みで付着すると、画像が著しく悪化する。そこで、トナー付着の厚みが１μｍ以上であったものをトナーフィルミングが発生したものとした。そして、トナーフィルミングの発生したものを×、発生しなかったものを○として表示した。
【００９８】
〔耐久性〕
上記３０００枚複写後のロールの状態を目視により評価した。すなわち、ロール表面が平滑であり、使用前の状態と比較して殆ど変化がないものを○、表面に凹みや削れ等が生じているものを×として表示した。
【００９９】
【表５】

【０１００】
【表６】

【０１０１】
【表７】

【０１０２】
上記表５〜表７の結果から、実施例品の現像ロールはすべて、比較例品の現像ロールに比べて、トナー帯電性に優れ、ロール回転トルクも小さくなっている。また、摩擦係数が低く、耐トナーフィルミング性や耐久性に優れ、複写画像の高画質化を実現している。
【０１０３】
【発明の効果】
以上のように、本発明のロールの製法は、軸体を有するロール基体と、溶剤可溶性ポリマー〔（ａ）成分〕およびブロックイソシアネート〔（ｂ）成分〕が特定の配合割合で配合された表面層形成用溶液とを準備する工程と、上記ロール基体の外周に上記表面層形成用溶液を塗工する工程と、上記表面層形成用溶液を塗工したロール基体を加熱処理することにより、ロール基体の外周に表面層を形成するとともに、上記ブロックイソシアネートのブロックを外しそのイソシアネート基と上記溶剤可溶性ポリマーの活性水素基を反応させて上記溶剤可溶性ポリマーをブロックイソシアネートにより架橋する工程とを備えている。このため、得られるロールの表面に存在する活性水素基を低減でき、しかも溶剤可溶性ポリマーを架橋することができる。したがって、トナーフィルミングが生じず、耐久性に優れたロールを得ることが可能となる。また、ブロックイソシアネートを用いているため、表面層形成用溶液の保存性が良好となって、作業面での利点が大きい。
【０１０４】
また、上記ブロックイソシアネート〔（ｂ）成分〕に代えてポリイソシアネート〔（ｂ′）成分〕を用いる、本発明の他の態様のロールの製法であっても、得られるロールの表面の活性水素基を低減でき、しかも溶剤可溶性ポリマーを架橋することができる。したがって、トナーフィルミングが生じず、耐久性に優れたロールを得ることが可能である。そして、この場合には、ブロックイソシアネートを用いる場合と異なり、ブロックを外すという操作が不要なため、ロールの製造を比較的効率良く行うことができる。
【０１０５】
特に、上記溶剤可溶性ポリマー〔（ａ）成分〕として、特定のポリマーを用いることにより、活性水素基を効率良く低減でき、しかも架橋効果が高いため、表面層の形成材料として好適である。
【０１０６】
さらに、上記加熱処理の温度として、前記特定の範囲となるよう設定することにより、活性水素基を効率良く低減でき、しかも表面層の形成状態を良好にできるという利点を有する。
【０１０７】
また、本発明のロールは、表面層が、溶剤可溶性ポリマー〔（ａ）成分〕およびブロックイソシアネート〔（ｂ）成分〕が特定の配合割合で配合された高分子組成物によって形成されている。このため、ロール表面の活性水素基は低減し、しかも表面層全体が架橋された状態になっている。したがって、本発明のロールは、トナーフィルミングが生じず、耐久性に優れたものとなっている。また、本発明のロールは、ブロックイソシアネートを用いて形成されているため、表面層形成用溶液の保存性の良好さに起因して、ロール形成状態がより安定するという利点を有する。
【０１０８】
そして、上記ブロックイソシアネート〔（ｂ）成分〕に代えてポリイソシアネート〔（ｂ′）成分〕を用いて得た、本発明の他の態様のロールであっても、ロール表面の活性水素基は低減しており、かつ表面層全体が架橋された状態になっている。したがって、この態様のロールは、トナーフィルミングが生じず、耐久性に優れたものとなっている。
【図面の簡単な説明】
【図１】 本発明のロールの製法の一例を示す断面図である。
【図２】 本発明のロールの一例を示す断面図である。
【図３】 電気抵抗の測定方法を説明するための説明図である。
【図４】 電気抵抗の測定方法を説明するための説明図である。
【図５】 摩擦係数の測定方法を説明するための説明図である。
【図６】 トナー帯電量の測定方法を説明するための説明図である。
【図７】 電子写真複写機の複写機構を説明するための説明図である。
【図８】 電子写真複写機の複写機構を説明するための説明図である。
【符号の説明】
１６ ロール基体
１７ 表面層
１８ 低硬度導電性ロール[0001]
BACKGROUND OF THE INVENTION
The present invention relates to production of a low-hardness conductive roll used for a developing roll, a charging roll, a transfer roll, etc., in an apparatus employing an electrophotographic technology such as an electrophotographic copying machine or a printer. To the law It is related.
[0002]
[Prior art]
In general, copying by an electrophotographic copying machine is performed as follows. In other words, a document image is formed as an electrostatic latent image on a photosensitive drum that rotates about its axis, and a toner image is formed by adhering toner to the image. Then, the toner image is transferred to a copy sheet for copying. is there. In this case, in order to form an electrostatic latent image on the surface of the photosensitive drum, the surface of the photosensitive drum is charged in advance, and a document image is projected onto the charged portion via the optical system, and is exposed to light. An electrostatic latent image is formed by canceling the charging of the portion. As a method for charging the surface of the photosensitive drum prior to the formation of the electrostatic latent image, recently, a roll charging method for charging the surface of the photosensitive drum by directly contacting the charging roll with the surface of the photosensitive drum has been adopted. . As a method of forming a toner image on the electrostatic latent image formed on the surface of the photosensitive drum in this manner, a method using the developing roll 1 (contact development method) is adopted as shown in FIG. That is, the toner 3 supplied from the toner supply port 2 is attached to the surface of the developing roll 1 that rotates in the direction of the arrow, and the electrostatic latent image portion on the surface of the photosensitive drum 4 that slidably contacts the developing roll 1 with the toner 3. Then, a toner image is formed on the surface of the photosensitive drum 4. In the figure, reference numeral 5 denotes a toner box. As shown in FIG. 8, the toner image formed in this way is transferred to the surface of the transfer roll 6 that is in sliding contact with the surface of the photosensitive drum 4 and transferred onto the transferred copy paper, and then the fixing roll. (Not shown) or the like is fixed on the copy paper. In this way, copying is performed.
[0003]
In the electrophotographic copying machine, rolls such as the developing roll 1, the transfer roll 6 and the charging roll (not shown) are used in contact with other members such as the photosensitive drum 4, so that the surface layer is low. Those set to hardness are used for prizes. As a material for forming such a surface layer, polyurethane having excellent wear resistance and compression strain resistance is widely used. As a roll using this, for example, the following (1) ~ (6) The following is disclosed.
[0004]
(1) A low-hardness conductive polyurethane roller obtained by a method in which a polyol having an average functional group number exceeding 2.0 and not more than 3.0 is reacted with polyisocyanate by a one-shot method (Japanese Patent Laid-Open No. 3-187732).
(2) A roll provided with an elastic layer formed of a polyurethane polymer composition having an NCO / OH ratio of 0.7 to 1.0 (JP-A-6-248174).
(3) A charging roller formed by using an elastomer obtained by a reaction at an NCO / OH ratio (molar ratio) of 0.9 to 1.2 as a main elastic layer material (Japanese Patent Laid-Open No. 7-110617).
(4) A conductive roller made of a polyurethane elastomer obtained by reacting with an isocyanate index of 80 to 120 (JP-A-9-114190).
(5) A developing roller having an outermost layer formed of a urethane elastomer composed of a hydrophilic or hydrophobic polyol and diphenylmethane diisocyanate (Japanese Patent Laid-Open No. 8-272211).
(6) A developing roll whose surface is treated with a solution containing an isocyanate-containing compound on the surface of a conductive polyurethane elastic body roll (Japanese Patent Laid-Open No. 5-313383).
[0005]
[Problems to be solved by the invention]
However, the above (1) ~ (5) However, there is a problem that the developer (toner) is fixed to the surface of the roll (hereinafter referred to as “toner filming”). on the other hand, (6) This roll is difficult to cause toner filming, but has a problem of poor durability because the surface is hard and brittle.
[0006]
The present invention has been made in view of the above circumstances, and produces a low-hardness conductive roll that does not cause toner filming and has excellent durability. Legal The purpose is to provide.
[0007]
[Means for Solving the Problems]
In order to achieve the above object, the present invention prepares a roll base having a shaft body, and the NCO / active hydrogen ratio is equivalent to an NCO / active hydrogen ratio of 2.5 to 35 as follows. (A) and (b) components of With conductive agent Preparing a surface layer forming solution blended with the above, a step of coating the surface layer forming solution on the outer periphery of the roll base, and heat-treating the roll base coated with the surface layer forming solution Thus, a surface layer is formed on the outer periphery of the roll base, the block of the component (b) is removed, and the isocyanate group and the hydroxyl group or amino group of the component (a) are reacted to convert the component (a) into the component (b). The manufacturing method of a low-hardness conductive roll provided with the process of bridge | crosslinking with a component is made into a 1st summary.
(A) A solvent-soluble polymer having a hydroxyl group or an amino group.
(B) Blocked isocyanate.
[0008]
In addition, the present invention provides a roll base having a shaft body, and the following (a) and (a) so that the NCO / active hydrogen ratio is an equivalent ratio of NCO / active hydrogen = 2.5 to 35. b ') component With conductive agent Preparing a surface layer forming solution blended with the above, a step of coating the surface layer forming solution on the outer periphery of the roll base, and heat-treating the roll base coated with the surface layer forming solution To form a surface layer on the outer periphery of the roll base, and react the isocyanate group of the component (b ′) with the hydroxyl group or amino group of the component (a) to convert the component (a) into the component (b ′). The manufacturing method of the low-hardness conductive roll provided with the process of bridge | crosslinking is made into a 2nd summary.
(A) A solvent-soluble polymer having a hydroxyl group or an amino group.
(B ') Polyisocyanate.
[0009]
That is, the present inventors have made a series of studies in order to obtain a low-hardness conductive roll that does not cause toner filming and has excellent durability. And first of all, (1) ~ (5) Research was conducted to find out the cause of toner filming in the rolls. As a result, it was ascertained that the hydroxyl group or amino group (hereinafter referred to as “active hydrogen group”) of the polymer existing on the surface of the roll was the starting point, and toner was successively deposited therefrom. Therefore, the present inventors recalled the use of a large excess amount of an isocyanate group-containing compound with respect to the active hydrogen group in order to eliminate the starting point of the toner filming, and further studied. In the process, it was conceived that the block isocyanate [(b) component] and the polyisocyanate [(b ′) component] should be used at a specific ratio with respect to the active hydrogen group. As a result, the present inventors have found a method for producing two embodiments of a low-hardness conductive roll (hereinafter simply referred to as “roll”). That is, a solution for forming a surface layer in which a solvent-soluble polymer having an active hydrogen group (hereinafter referred to simply as “solvent-soluble polymer” (component (a)) and a blocked isocyanate (component (b)) is blended at a specific blending ratio) Preparing, coating this on the surface of a roll substrate, and then heat-treating to remove the block of the blocked isocyanate, react the isocyanate group with the active hydrogen group of the solvent-soluble polymer, and convert the solvent-soluble polymer into the blocked isocyanate. It has been found that a roll excellent in durability can be obtained without causing toner filming by cross-linking by the above, and the present invention has been achieved. Further, instead of the above-mentioned blocked isocyanate [component (b)], polyisocyanate [component (b ′)] is used, whereby the active hydrogen group of the solvent-soluble polymer is reacted with the isocyanate group to be crosslinked, It has been found that a roll excellent in durability can be obtained without toner filming, and the present invention has been achieved. In addition, when block isocyanate [(b) component] was used, it discovered that especially the preservability of the solution for surface layer formation became favorable.
[0010]
The solvent-soluble polymer [component (a)] includes the specific polymer [(a ₁ It was found that it is particularly preferable to use the component)) as a material for forming the surface layer.
[0011]
Furthermore, when the temperature of the heat treatment was set so as to be in the specific range, it was found that the active hydrogen groups of the solvent-soluble polymer were efficiently reduced, and the surface layer formation state became better.
[0012]
Also, a roll base having a shaft body and a roll having a surface layer on the outer periphery of the roll base, the surface layer comprising the solvent-soluble polymer (component (a)) and the blocked isocyanate (component (b)) It was found that a roll formed of a polymer composition blended at a specific blending ratio does not cause toner filming and has excellent durability. In addition, it has been found that the roll formation state is more stable due to the good storage stability of the surface layer forming coating. A roll base having a shaft body and a roll having a surface layer on the outer periphery of the roll base, the surface layer comprising the solvent-soluble polymer [component (a)] and the polyisocyanate [component (b ′)] It has been found that if the roll is formed of a polymer composition blended at a specific blending ratio, toner filming does not occur and the durability is excellent.
[0013]
In the roll of the present invention, “low hardness” means that the measured value of hardness according to JIS A is 70 ° or less, and “conductivity” means electricity measured according to the method of JIS K 6911. Resistance is 10 ⁹ Ω or less. In the present invention, the “NCO / active hydrogen ratio” means the ratio of isocyanate groups to active hydrogen groups. Furthermore, in the present invention, “block isocyanate” is a general term for polyisocyanates in which isocyanate groups are blocked by a blocking agent.
[0014]
DETAILED DESCRIPTION OF THE INVENTION
Next, embodiments of the present invention will be described in detail.
[0015]
In the roll manufacturing method of the present invention, a roll base having a shaft body and a surface layer forming solution are used.
[0016]
The roll base having the shaft body may be composed only of the shaft body, or may be formed in advance on the outer periphery of the shaft body.
[0017]
The shaft body is not particularly limited as long as it has conductivity, and a metal core made of a metal solid body or a metal cylinder body hollowed out inside is used. Examples of the material for the shaft include aluminum and stainless steel.
[0018]
The material for forming at least one layer on the outer periphery of the shaft body is not particularly limited, and a conventionally known material may be used. For example, in the case where the innermost layer is formed on the outer periphery of the shaft body and the intermediate layer is formed on the outer periphery, the innermost layer is formed by using liquid silicone, two-component reactive urethane, styrene-butadiene rubber (SBR), acrylonitrile. -Base polymer component of general-purpose rubber such as butadiene rubber (NBR), natural rubber (NR), silicone rubber, urethane rubber, ethylene-propylene-diene rubber (EPDM), carbon black, graphite, iron oxide, zinc oxide, titanium oxide , And a compound containing a conductive agent such as a metal oxide such as tin oxide, a quaternary ammonium salt, or a borate. As the material for forming the intermediate layer, a material obtained by blending a conductive agent with hydrogenated nitrile rubber (H-NBR) or the like is used.
[0019]
Then, using each of the above materials, for example, a roll base can be obtained as follows. That is, first, each component constituting the innermost layer forming material is kneaded using a kneader or the like to prepare a compound innermost layer forming material. Moreover, each component which comprises the said intermediate | middle layer formation material is disperse | distributed using a ball mill, a sand mill, etc., and organic solvent, such as methyl ethyl ketone (MEK), is added and mixed, and it stirs, The coating liquid for intermediate | middle layer formation is obtained. Prepare. Next, as shown in FIG. 1, the compound innermost layer forming material 14 is cast into the lower lid 12 and the cylindrical mold 13 on which the shaft body 11 is set, and the upper lid 15 is externally fitted to the cylindrical mold 13. . In this state, the entire roll mold is heated to crosslink the compound innermost layer forming material 14 to form the innermost layer 9. Next, after removing the shaft 11 on which the innermost layer 9 is formed, the coating liquid is applied to the outer peripheral surface of the innermost layer 9, and drying and heat treatment are performed. An intermediate layer is formed on the outer peripheral surface. In addition, the coating method of the said coating liquid is not restrict | limited in particular, Conventionally well-known coating methods, such as a dipping method, a spray coating method, a roll coating method, can be applied. In this way, a roll base 16 in which the innermost layer 9 and the intermediate layer 10 are formed in this order on the outer periphery of the shaft body 11 is obtained (see FIG. 2).
[0020]
Examples of the surface layer forming solution used together with the roll substrate 16 include a solution obtained by adding a solvent to a surface layer forming material such as a solvent-soluble polymer [component (a)] or a blocked isocyanate [component (b)].
[0021]
The solvent-soluble polymer [component (a)] is not particularly limited as long as it has an active hydrogen group and is soluble in a solvent. Even a linear polymer may be a branched polymer. Also good. Specific examples include thermoplastic polyurethane, silicone-modified urethane, silicone-grafted acrylic polymer, and acrylic polyol.
[0022]
The thermoplastic polyurethane (TPU) is a combination of a hard segment and a soft segment, and has an active hydrogen group at the terminal.
[0023]
Examples of the material used for the hard segment include isocyanate materials such as diphenylmethane diisocyanate (MDI), tolylene diisocyanate (TDI), hexamethylene diisocyanate (HDI), and isophorone diisocyanate (IPDI). In addition, examples of the material provided for the soft segment include adipate polyols such as ethylene adipate (EA), butylene adipate (BA), hexamethylene adipate (HA), capropolyols such as polycaprolactam (PCL), Examples thereof include carbonate-based polyols such as hexamethylene carbonate polyester (PCP), and polyol-based materials such as polypropylene glycol (PPG) and ether-based polyols such as polytetramethylene glycol (PTMG).
[0024]
The thermoplastic polyurethane can be produced, for example, as follows using the isocyanate material and the polyol material. That is, it can be prepared by blending them in a predetermined ratio, reacting in the presence of a catalyst, and taking out the mixture when the viscosity is stable. In the reaction, chain extenders such as ethylene glycol, propylene glycol, 3,3′-dichloro-4,4′-diaminodiphenylmethane (MOCA), trimethylolpropane (TMP), hydroquinone diethylol ether (BHEB), etc. A curing agent may be added.
[0025]
In addition, although the said thermoplastic polyurethane can be produced as mentioned above, you may use a commercial item. As such a product, for example, Nippon Run 2304 (manufactured by Nippon Polyurethane Co., Ltd., butylene adipate TPU) is known.
[0026]
The silicone-modified urethane has a siloxane bond (Si-O bond), an active hydrogen group at both ends (A), tolylene diisocyanate (TDI), 4,4'-diphenylmethane diisocyanate (MDI). ) And other bifunctional isocyanates. Especially, the thing of the range whose molecular weight of silicone modified urethane is 500-10000 is preferable, More preferably, it is 1000-4000. And the content rate of the siloxane bond in this silicone modified urethane is preferably 10 to 99% by weight, particularly preferably 40 to 80% by weight.
[0027]
As the special compound (A) that is a constituent component of the silicone-modified urethane, specifically, polydimethylsiloxane dicarbinol represented by the following general formula (1) is preferable.
[0028]
[Chemical 1]

[0029]
In the general formula (1), R ¹ , R ² Examples of the alkylene group having 1 to 20 carbon atoms represented by: methylene group, ethylene group, propylene group, butylene group, hexylene group, octylene group, dodecylene group and the like. In addition, the repeating number n in the general formula (1) is selected as a positive number such that the molecular weight of the polydimethylsiloxane dicarbinol is in the range of 500 to 10,000, preferably in the range of 1000 to 6000. A positive number is chosen such that
[0030]
As said silicone modified urethane, the compound which substituted at least one part of the methyl group in the said General formula (1) by the specific substituent can also be used. Examples of the specific substituent include an alkenyl group such as an alkyl group having 2 to 30 carbon atoms, a haloalkyl group, a cyanoalkyl group, an allylalkyl group, a vinyl group, and an acrylic group, an allyl group, an alkylallyl group, and an alkenylallyl group. , A haloallyl group, a hydrogen atom, a halogen atom and the like. These may be used alone or in combination of two or more.
[0031]
The silicone-modified urethane can be produced, for example, as follows. That is, the special compound (A) and the difunctional isocyanate are blended at a predetermined blending ratio, and the reaction is performed in the presence of a conventionally known urethanization catalyst such as dibutyltin dilaurate (DBTDL) (reaction conditions: 80 to 120 ° C. × 1 to 5 hours), a linear prepolymer is prepared by taking out at a stable viscosity, and a chain extender or polyol is added as necessary to carry out the reaction (reaction conditions: 80 to 120 ° C. × 1 to 5 hours), and it can be prepared by dissolving it in a solvent.
[0032]
Furthermore, the silicone graft acrylic polymer has a structure represented by the following general formula (2).
[0033]
[Chemical 2]

[0034]
In the said General formula (2), the repeating number k is a positive number of 1-3000, Preferably it is a positive number of 1-300. Moreover, the repeating number n is a positive number of 1 to 3000, preferably a positive number of 1 to 300.
[0035]
In the general formula (2), Y is a linear structure portion derived from an acrylic monomer. Specific examples of the acrylic monomer include acrylic acid, methyl acrylate, ethyl acrylate, octyl acrylate, dodecyl acrylate, 2-ethylhexyl acrylate, propyl acrylate, n-butyl acrylate, and acrylic. Isobutyl acid, sec-butyl acrylate, tert-butyl acrylate, 2,2-dimethylpropyl acrylate, cyclohexyl acrylate, 2-tert-butylphenyl acrylate, 2-naphthyl acrylate, phenyl acrylate, acrylic acid 4-methoxyphenyl, 2-methoxycarbonylphenyl acrylate, 2-ethoxycarbonylphenyl acrylate, 2-chlorophenyl acrylate, 4-chlorophenyl acrylate, benzyl acrylate, 2-cyanobenzyl acrylate, 4-acrylic acid 4- Anophenyl, p-tolyl acrylate, isononyl acrylate, 2-hydroxyethyl acrylate, 2-hydroxypropyl acrylate, 2-hydroxybutyl acrylate, 2-cyanoethyl acrylate, 3-oxabutyl acrylate, acrylamide, methacrylic acid, Methyl methacrylate, ethyl methacrylate, octyl methacrylate, dodecyl methacrylate, 2-ethylhexyl methacrylate, propyl methacrylate, n-butyl methacrylate, isobutyl methacrylate, sec-butyl methacrylate, tert-butyl methacrylate, methacrylic acid 2,2-dimethylpropyl, cyclohexyl methacrylate, 2-tert-butylphenyl methacrylate, 2-naphthyl methacrylate, phenyl methacrylate, 4-methacrylate Siphenyl, 2-methoxycarbonylphenyl methacrylate, 2-ethoxycarbonylphenyl methacrylate, 2-chlorophenyl methacrylate, 4-chlorophenyl methacrylate, benzyl methacrylate, 2-cyanobenzyl methacrylate, 4-cyanophenyl methacrylate, methacrylic acid p-tolyl, isononyl methacrylate, 2-hydroxyethyl methacrylate, 2-hydroxypropyl methacrylate, 2-hydroxybutyl methacrylate, 2-cyanoethyl methacrylate, 3-oxabutyl methacrylate, γ-methacryloyloxypropyltrimethoxysilane, Acrylamide, butylacrylamide, N, N-dimethylacrylamide, piperidylacrylamide, methacrylamide, 4-carboxyphenylmethacrylamide 4-methoxycarboxyphenyl methacrylamide, methyl chloroacrylate, ethyl-α-chloroacrylate, propyl-α-chloroacrylate, isopropyl-α-chloroacrylate, methyl-α-fluoroacrylate, butyl-α-butoxycarbonyl methacrylate, butyl- Examples include α-cyanoacrylate, methyl-α-phenyl acrylate, isobornyl acrylate, isobornyl methacrylate, diethylaminoethyl methacrylate, and the like. And the linear structure part represented by Y is comprised when 1 type of these acrylic monomers polymerizes or 2 types or more copolymerize.
[0036]
In the general formula (2), Z is a structural part derived from an acrylic monomer, and has a structural part derived from siloxane in the side chain. This is derived from what is represented by the following general formula (3) or general formula (4).
[0037]
[Chemical 3]

[0038]
[Formula 4]

[0039]
And as a preferable specific example of the said General formula (3) or General formula (4), what is shown to following structural formula (Z-1)-(Z-18) is mention | raise | lifted.
[0040]
[Chemical formula 5]

[0041]
[Chemical 6]

[0042]
[Chemical 7]

[0043]
[Chemical 8]

[0044]
And the silicone graft acrylic polymer provided with the structure represented by the said General formula (2) can be manufactured as follows, for example. That is, the above (Y) _k Part and (Z) _n The part can be produced by radical polymerization (polymerization conditions: 50 to 150 ° C. × 3 to 100 hours) in the presence of an azo polymerization initiator such as azobisisobutyronitrile (AIBN). Such polymerization can be performed by a solution polymerization method using a solvent, a bulk polymerization method, an emulsion polymerization method, or the like, and particularly preferably a solution polymerization method.
[0045]
The silicone graft acrylic polymer has a structure represented by the general formula (2), and a linear structure portion derived from an acrylic monomer is further linked to this structure. Alternatively, a structure represented by the following general formula (5) may be provided.
[0046]
[Chemical 9]

[0047]
In the general formula (5), X is a linear structure portion derived from an acrylic monomer. And as said acrylic monomer, the thing similar to what was illustrated in the said General formula (2) is mention | raise | lifted. However, Y and X must be different from each other.
[0048]
In the said General formula (5), the repeating number n is a positive number of 1-3000, Preferably, it is a positive number of 1-300.
[0049]
In addition, although the said silicone graft acrylic polymer can be produced as mentioned above, you may use a commercial item. As such a thing, Cymac US270 (made by Toa Gosei Co., Ltd.) and X-22-8004 (made by Shin-Etsu Chemical Co., Ltd.) are known, for example.
[0050]
The acrylic polyol has a structure represented by the following general formula (6).
[0051]
[Chemical Formula 10]

[0052]
In the said General formula (6), the repeating number k is a positive number of 1-3000, Preferably it is a positive number of 1-300. Moreover, the repeating number n is a positive number of 1 to 3000, preferably a positive number of 1 to 300.
[0053]
In the general formula (6), Y is a linear structure portion derived from an acrylic monomer. Examples of such an acrylic monomer include those described above. And the linear structure part represented by Y is comprised when 1 type of these acrylic monomers superposes | polymerizes or 2 types or more copolymerize.
[0054]
In the general formula (6), W is a structural portion derived from an acrylic monomer and has an active hydrogen group. This is derived from the same acrylic monomer as described above. Further, a polymer obtained by reacting with a bifunctional isocyanate, a chain extender or the like may be used.
[0055]
In addition, although the said acrylic polyol can be produced as mentioned above, you may use a commercial item. Examples of such devices include Samprene IB (manufactured by Sanyo Chemical Co., Ltd.) and SK Dyne AG105 (manufactured by Soken Chemical Co., Ltd.).
[0056]
In the present invention, the blocked isocyanate [component (b)] used together with the solvent-soluble polymer [component (a)] includes those obtained by reacting polyisocyanate with a blocking agent. This blocked isocyanate [component (b)] may be used alone or in combination of two or more.
[0057]
Although it does not specifically limit as said polyisocyanate, The thing which is not volatile at the time of high temperature is preferable. Specific examples include isocyanate compounds such as hexamethylene diisocyanate (HMDI), tolylene diisocyanate (TDI), diphenylmethane diisocyanate (MDI), carbodiimide-modified MDI, isophorone diisocyanate (IPDI), and crude MDI. Further, adducts and burettes of these isocyanate compounds can be used. Furthermore, the isocyanurate body which has an isocyanurate ring obtained by making it react in presence of a catalyst using these isocyanate compounds can be used. Among these, isocyanurate is preferable because it is very stable at room temperature and does not cause yellowing during overbaking.
[0058]
The blocking agent is not particularly limited as long as it is capable of blocking an isocyanate group and has a property that the block can be removed by heating after blocking, but is volatile and active. A hydrogen group-containing compound is preferred. Specifically, alcohols such as 2-ethylhexanol, phenols such as phenol, cresol and isononylphenol, oximes such as ε-caprolactam and methyl ethyl ketoxime, activity such as diethyl malonate and ethyl acetoacetate And methylene compounds. These may be used alone or in combination of two or more.
[0059]
Then, using the polyisocyanate and the blocking agent, for example, the blocked isocyanate [component (b)] can be prepared as follows. That is, it can be produced by dropping a substantially equivalent blocking agent with respect to polyisocyanate while keeping it at a predetermined temperature (about 40 to 60 ° C.). Moreover, as other methods, for example, when preparing an isocyanurate body, the amount of the blocking agent that is approximately half the equivalent to the isocyanate compound is maintained at a predetermined temperature (about 40 to 60 ° C.). The half block body is produced by dropping. Subsequently, it can be produced by adding isocyanurate by adding potassium octylate, cellosolve acetate or the like. When the blocked isocyanate is produced using the above-mentioned method other than the above, the isocyanate group having higher reactivity can be blocked, and the isocyanate group having relatively low reactivity can be used for isocyanurate bonding. For this reason, the active hydrogen group of the solvent-soluble polymer [component (a)] can be blocked more efficiently.
[0060]
In addition, although the said block isocyanate [(b) component] can be obtained by making polyisocyanate and a blocking agent react as mentioned above, you may use a commercial item. For example, Coronate 2513 (manufactured by Nippon Polyurethane Co., Ltd.), Barnock D550, Barnock D500, Barnock B8-117, and Barnock DB980k (all four manufactured by Dainippon Ink, Inc.) are known. The Bernock DB 980k is obtained according to the following chemical formula (7).
[0061]
Embedded image

[0062]
In addition to the solvent-soluble polymer [component (a)] and blocked isocyanate [component (b)], the surface layer forming material contains a dissociation catalyst for the purpose of easily removing the block of the blocked isocyanate [component (b)]. May be. When this dissociation catalyst is used, the temperature of the heat treatment in the roll production process can be reduced. Examples of the dissociation catalyst include tin compounds such as 1,3-diacetoxytetrabutylstannoxane and dibutyltin dilaurate, and tertiary amines such as N-methylmorpholine.
[0063]
For the surface layer forming material, Suitable Positive volume resistivity (10 ^Five -10 ¹¹ Ω · cm) for the purpose of providing a conductive agent The The characteristic concerning this volume electrical resistance is important as the characteristic of the surface layer of a developing roll, for example. As the conductive agent, c-TiO ₂ , C-ZnO, ketjen black, carbon black such as acetylene black, c-SnO ₂ Iron oxide, graphite, potassium titanate, quaternary ammonium salt, borate, lithium salt and the like. These may be used alone or in combination of two or more. Among these, c-TiO can be obtained because it can obtain an appropriate volumetric electrical resistance. ₂ , C-ZnO, acetylene black, and quaternary ammonium salts are preferably used. In addition, the above “c−” means having conductivity.
[0064]
In addition to the above, the surface layer forming material includes a charge control agent, a filler, a stabilizer, an ultraviolet absorber, an antistatic agent, a reinforcing agent, a lubricant, a release agent, a dye, a pigment, a flame retardant, an oil, and the like. Can be appropriately blended as necessary.
[0065]
Examples of the solvent used together with the surface layer forming material include tetrahydrofuran (THF), methyl ethyl ketone (MEK), methyl isobutyl ketone (MIBK), toluene, ethyl acetate and the like.
[0066]
Then, using the surface layer forming material and the solvent, a surface layer forming solution is prepared as follows. That is, the solvent-soluble polymer [component (a)] and the blocked isocyanate [component (b)] are blended in the solvent so that the NCO / active hydrogen ratio is in the range of 2.5 to 35 in terms of equivalent ratio. Both Contains a conductive agent Dissociate touch if necessary Medium It can produce by mix | blending. A more preferable range of the NCO / active hydrogen ratio is 5-15. That is, if the NCO / active hydrogen ratio is less than 2.5, the number of isocyanate groups is too small to reduce the active hydrogen groups sufficiently, and if the NCO / active hydrogen ratio exceeds 35, it is obtained. This is because the surface of the roll to be hardened makes it difficult to reduce the hardness of the substrate and increases the torque load. The NCO / active hydrogen ratio is calculated on the assumption that the block isocyanate [component (b)] is unblocked.
[0067]
In the present invention, using the roll substrate and the surface layer forming solution, for example, a roll is produced as follows. That is, first, according to the method described above, a roll substrate and a surface layer forming solution are prepared. Next, the surface layer forming solution is applied to the outer peripheral surface of the roll base by a conventionally known method such as a dipping method or a roll coating method to form a liquid film. Then, after coating, by heating at a predetermined temperature, the solvent in the liquid film is volatilized to form a surface layer, and the isocyanate group in the blocked isocyanate [component (b)] is unblocked and exposed. The isocyanate group thus reacted reacts with the active hydrogen group of the solvent-soluble polymer [component (a)] to crosslink. In this way, the roll 18 shown in FIG. 2 in which the surface layer 17 is formed on the outer peripheral surface of the roll base 16 can be produced.
[0068]
In the said manufacturing method, it is preferable that the temperature of heat processing is set to the range of 130-250 degreeC. More preferably, it is the range of 150-200 degreeC. That is, if the temperature of the heat treatment is less than 130 ° C., the block of the blocked isocyanate [component (b)] may not be removed. On the contrary, if the temperature of the heat treatment exceeds 250 ° C., the polymer of the roll base or the surface layer may be decomposed.
[0069]
According to the above production method, active hydrogen groups can be effectively reduced, and thus a roll 18 that does not cause toner filming can be obtained. Further, in reducing the active hydrogen group, the polyisocyanate from which the blocking agent has been removed functions as a crosslinking agent, so that it can reduce the tackiness with respect to the surface layer 17 and obtain a roll 18 having excellent durability. it can. Furthermore, since blocked isocyanate [component (b)] is used for blocking active hydrogen groups, the storage stability of the surface layer forming solution during roll production can be improved.
[0070]
In the roll 18 thus obtained, the thickness of each layer is determined as appropriate. For example, when used for a developing roll, the thickness of the innermost layer is determined in the range of 0.5 to 10 mm. Preferably, it is 3 to 6 mm. Moreover, it is preferable to set the thickness of an intermediate | middle layer to the range of 1-90 micrometers, More preferably, it is 3-15 micrometers. And it is preferable to set the thickness of a surface layer to the range of 5-100 micrometers, More preferably, it is 5-30 micrometers.
[0071]
In the present invention, polyisocyanate [(b ′) component] may be used in place of the blocked isocyanate [(b) component]. As this polyisocyanate [component (b ′)], diphenylmethane diisocyanate (MDI), isophorone diisocyanate (IPDI), dicyclohexylmethane diisocyanate (hydrogenated MDI), trimethylhexamethylene diisocyanate (TMHDI), tolylene diisocyanate (TDI), carbodiimide Modified MDI, polymethylene phenyl polyisocyanate (PAPI), orthotoluidine diisocyanate (TODI), naphthylene diisocyanate (NDI), xylene diisocyanate (XDI), hexamethylene diisocyanate (HMDI), paraphenylene diisocyanate (PDI), lysine diisocyanate methyl ester (LDI), isocyanate compounds such as dimethyl diisocyanate (DDI) And the like. Moreover, adduct bodies and burette bodies of these isocyanate compounds can be used. Furthermore, the isocyanurate body which has an isocyanurate ring obtained by making it react in presence of a catalyst using these isocyanate compounds can be used. Of these, isocyanurate is preferable because it is very stable at room temperature and does not cause yellowing during overbaking. Furthermore, a TMP TMP adduct and an HDI isocyanurate are preferred because they do not react vigorously when mixed with the solvent-soluble polymer [component (a)] and there is no problem in production. And when this polyisocyanate [(b ') component] is used, since the operation which removes a block is unnecessary, it has the advantage that a roll can be obtained efficiently.
[0072]
The roll of the present invention can be used as a paper feed roll, a charging roll, a developing roll, a transfer roll, a fixing roll, and the like, and particularly preferably used as a developing roll.
[0073]
Next, examples will be described together with comparative examples.
[0074]
[Production of roll substrate]
First, prior to the examples and comparative examples, a roll base having an innermost layer on the outer periphery of the shaft body and an intermediate layer on the outer periphery of the innermost layer was prepared. That is, a core metal (diameter 10 mm, made of SUS304) as a shaft, a liquid silicone rubber added with carbon black as an innermost layer forming material, and a hydrogenated nitrile rubber added with carbon black as an intermediate layer forming material In accordance with the method described above, the innermost layer (thickness: 5 mm) was formed on the outer peripheral surface of the shaft body, and the intermediate layer (thickness: 10 μm) was further formed on the outer peripheral surface. The roll substrate had a JIS A hardness of 30 °.
[0075]
Examples 1 to 10
A solvent-soluble polymer shown in Table 1 below and a curing agent shown in Table 2 below were prepared. Next, each component shown in the following Table 3 and Table 4 was mix | blended in the mixture ratio shown to the same table, and the solution for surface layer formation was produced. Next, this surface layer forming solution is applied to the outer peripheral surface of the roll base according to the above-described method (dipping method), and then heat-treated under the conditions shown in the same table to form a surface layer (thickness: 15 μm). A desired developing roll was prepared.
[0076]
[Table 1]

[0077]
[Table 2]

[0078]
[Table 3]

[0079]
[Table 4]

[0080]
[Comparative Example 1]
A developing roll was prepared in accordance with JP-A-5-31383. Specifically, it was produced according to the following procedure.
[0081]
[Roll manufacturing method]
After adding 0.05 part by weight of lithium perchlorate to 100 parts by weight of polyester polyol (Kurapol P-2010, manufactured by Kuraray Co., Ltd.), stirring and dissolving, the temperature was adjusted to 100 ° C. and then coronate HX (Nippon Polyurethane Co., Ltd.). 20 parts by weight) and 20 parts by weight of alcohol-modified silicone oil (SF-8427, manufactured by Toray Dow Corning) were added and stirred to obtain a mixture. This mixture is poured into a mold preheated to 120 ° C. in which a shaft is placed in advance, and heated at 120 ° C. for 60 minutes, and a conductive polyurethane elastic layer is formed on the surface of the shaft excluding both ends. A rolled substrate was obtained.
[0082]
[Preparation of surface treatment solution]
100 parts by weight of MR400 (manufactured by Nippon Polyurethane) was dissolved in 900 parts by weight of ethyl acetate to obtain a surface treatment solution.
[0083]
[Roll substrate surface treatment]
While maintaining the solution at 20 ° C., the roll substrate was immersed for a predetermined time, and then heated in an oven maintained at 100 ° C. for 10 hours to obtain a developing roll.
[0084]
[Comparative Example 2]
A developing roll was prepared in accordance with JP-A-8-272211. That is, 6.5 parts of 1,4-butanediol was added to 100 parts by weight of a prepolymer obtained by reacting tolylene diisocyanate so that NCO% was 6.7 with a polyether polyol having 3 functional groups and a molecular weight of 5000. Parts by weight, 2 parts by weight of a silicone surfactant, 0.01 parts by weight of dibutyltin dilaurate and 2.0 parts by weight of acetylene black were added and stirred for 2 minutes using a mixer. The reaction mixture was poured into a mold preheated to ℃ and cured at 60 ℃ for 12 hours. After removing the mold, polishing was performed to obtain a roll base having an outer layer of urethane foam. Next, 100 parts by weight of a polyisoprene polyol having a functional group number of 2.35 and a molecular weight of 2800 was degassed under vacuum for 30 minutes, and then 12.7 parts by weight of crude diphenylmethane-4,4′diisocyanate having an NCO% of 31.7%, dibutyl. Add 0.01 parts by weight of tindilaurate and 3.5 parts by weight of acetylene black and stir for 3 minutes while degassing again under reduced pressure. Then, the roll base obtained above is set in advance and the mold is preheated to 90 ° C. Poured, cured at 90 ° C. for 16 hours, removed from the mold, and then polished. In this way, a two-layer developing roll having a hydrophobic urethane elastomer as the outermost layer and urethane worm inside was obtained.
[0085]
[Comparative Example 3]
A developing roll was prepared according to JP-A-9-114190. That is, first, a polyurethane elastomer was prepared according to the following procedure.
[0086]
(Preparation of polyol component)
75 parts by weight of polypropylene polyol A (manufactured by Sumitomo Bayer Urethane Co., Ltd.), 25 parts by weight of polypropylene polyol B (manufactured by Sumitomo Bayer Urethane Co., Ltd.), and 2 parts by weight of carbon black (manufactured by Lion Akzo Co., Ltd.) Kneaded with. Next, 0.2 part by weight of DBU-phenol salt (manufactured by San Apro) and 0.1 part by weight of dibutyltin dilaurate (manufactured by Nitto Kasei) were added to the above mixture and stirred to disperse the catalyst. . After the mixture became uniform, vacuum dehydration was performed at 40 ° C. and 3 Torr for 3 hours or more.
[0087]
[Preparation of prepolymerized isocyanate]
6.33 parts by weight of HDI was added to 2.86 parts by weight of polypropylene polyol C (manufactured by Sumitomo Bayer Urethane Co., Ltd.), and after stirring, reacted at 70 ° C. under a nitrogen atmosphere for 24 hours to obtain a prepolymerized isocyanate having a terminal NCO group. .
[0088]
[Preparation of polyurethane elastomer]
The prepolymerized isocyanate prepared with the prepolymerized isocyanate was weighed and added to the polyol component so that the isocyanate index was 105. The prepolymerized isocyanate at the time of addition and the liquid temperature of the polyol component were both about 40 ° C. After the prepolymerized isocyanate was added, the mixture was stirred with an agitator.
[0089]
Next, a stainless steel shaft body having an outer periphery coated with an adhesive was set in a mold and held at 70 ° C. The mixture was poured into this mold and reacted and cured for about 10 minutes to form a conductive elastic layer made of polyurethane elastomer. This was demolded and aged at room temperature for about 24 hours. Then, the surface of this electroconductive elastic layer was grind | polished with the grinder, and the image development roll was obtained.
[0090]
For each developing roll thus obtained, measurement or evaluation of hardness, electrical resistance, friction coefficient, roll rotation torque, toner charge amount, copy image quality evaluation, filming resistance, durability according to the following method The results are shown in Tables 5 to 7 below.
[0091]
〔hardness〕
The hardness according to JIS A was measured. As a result, as described above, if the measured value is 70 ° or less, it is in the range of “low hardness” in the roll of the present invention.
[0092]
[Electric resistance]
After preparing the electrode 19 having the shape shown in FIG. 3 and installing 20 electrodes on the roll surface, the measurement was performed by the measurement system shown in FIG. In FIG. 3, 19a is a main electrode and 19b is a guard electrode. Moreover, in FIG. 4, 20 is a roll. In addition, the electrical resistance value was shown as a median value of 20 measured values. As a result, as described above, the measured value is 10 ⁹ If it is Ω or less, it is in the range of “conductivity” in the roll of the present invention.
[0093]
〔Coefficient of friction〕
The friction coefficient was measured using a static friction coefficient meter (manufactured by Kyowa Interface Chemical Co., Ltd.) as shown in FIG. That is, a coating film 21 having a thickness of 50 to 100 μm was prepared, and this was set on a fixed base 22 and measured under conditions of a moving speed of 0.3 cm / second and a load of 100 g. In the figure, reference numeral 23 denotes a steel ball (diameter 3 mm), 24 denotes a zero adjustment balance, 25 denotes a load cell, and 26 denotes a load (100 g).
[0094]
[Roll rotation torque]
Each developing roll is pressed against the photosensitive member with a pressure of about 0.3 mm in the radial direction, and each roll is rotated by a torque motor, and the current value at the beginning of the movement is measured. did. Then, the obtained measured value was converted into torque, and the case where the calculated value was less than 3 kgf-cm was indicated as ◯, and the case where it was 3 kgf-cm or more was indicated as x.
[0095]
[Toner chargeability]
The toner chargeability was measured as follows under the condition that the charge amount on the developing roll was 20 ° C. × 50% RH. That is, as shown in FIG. 6, a developer (toner) 32 layer was formed on the surface of the developing roll 30, and the developer 32 was sucked by the suction pump 33 and measured by the Faraday cage 34 (Faraday cage method). In the drawing, 35 is a filter, 36 is an insulator pipe, 37 is an electrometer, and 38 and 39 are separated from each other by a conductor. It can be said that the larger the absolute value of the measured value, the better the toner chargeability.
[0096]
[Image quality evaluation of copied images]
The image quality of the copied image at the initial stage of copying and after copying 3000 sheets was visually evaluated. That is, characters were copied, and there was no problem in the copied image, and those with fine lines clearly copied were displayed as ◯, and those with faint or fogging were displayed as X. Note that the fading means that the thin line is broken, and the fogging means that the toner is flying where there is no image.
[0097]
[Film resistance]
A portion where the developer (toner) thickly adheres to the surface of the developing roll has poor chargeability and causes a defective copy image. Specifically, when a part of the developer adheres to the surface of the developing roll with a thickness of 1 μm or more, the image is remarkably deteriorated. Therefore, toner filming was determined to occur when the toner adhesion thickness was 1 μm or more. The case where toner filming occurred was indicated as x, and the case where toner filming did not occur was indicated as ◯.
[0098]
〔durability〕
The state of the roll after copying 3000 sheets was visually evaluated. That is, the roll surface was smooth, and there was almost no change compared to the state before use, and the case where the surface was dented or scraped was indicated as x.
[0099]
[Table 5]

[0100]
[Table 6]

[0101]
[Table 7]

[0102]
From the results of Tables 5 to 7, all of the development rolls of the example products are superior in toner chargeability and have a smaller roll rotation torque than the development rolls of the comparative examples. In addition, it has a low coefficient of friction, excellent toner filming resistance and durability, and realizes high-quality copy images.
[0103]
【The invention's effect】
As described above, the roll production method of the present invention comprises a roll substrate having a shaft, a surface layer in which a solvent-soluble polymer [component (a)] and a blocked isocyanate [component (b)] are blended at a specific blending ratio. A step of preparing a forming solution, a step of applying the surface layer forming solution to the outer periphery of the roll substrate, and heat-treating the roll substrate coated with the surface layer forming solution, whereby the roll substrate Forming a surface layer on the outer periphery of the resin, and removing the block of the blocked isocyanate to react the isocyanate group with the active hydrogen group of the solvent-soluble polymer to crosslink the solvent-soluble polymer with the blocked isocyanate. For this reason, the active hydrogen group which exists in the surface of the obtained roll can be reduced, and also a solvent soluble polymer can be bridge | crosslinked. Therefore, toner filming does not occur, and a roll having excellent durability can be obtained. Moreover, since the block isocyanate is used, the storage stability of the solution for forming the surface layer is good, and the advantage in terms of work is great.
[0104]
Moreover, even if it is a manufacturing method of the roll of the other aspect of this invention which uses polyisocyanate [(b ') component instead of the said block isocyanate [(b) component], the active hydrogen group on the surface of the roll obtained And the solvent-soluble polymer can be crosslinked. Therefore, it is possible to obtain a roll excellent in durability without toner filming. In this case, unlike the case of using blocked isocyanate, the operation of removing the block is unnecessary, so that the roll can be manufactured relatively efficiently.
[0105]
In particular, by using a specific polymer as the solvent-soluble polymer [component (a)], the active hydrogen groups can be efficiently reduced, and the crosslinking effect is high, so that it is suitable as a material for forming the surface layer.
[0106]
Furthermore, by setting the temperature of the heat treatment so as to be in the specific range, there are advantages that active hydrogen groups can be efficiently reduced and the surface layer can be well formed.
[0107]
In the roll of the present invention, the surface layer is formed of a polymer composition in which a solvent-soluble polymer [component (a)] and a block isocyanate [component (b)] are blended in a specific blending ratio. For this reason, the active hydrogen groups on the roll surface are reduced, and the entire surface layer is crosslinked. Therefore, the roll of the present invention does not cause toner filming and has excellent durability. Moreover, since the roll of this invention is formed using block isocyanate, it has the advantage that a roll formation state becomes more stable resulting from the favorable preservation property of the solution for surface layer formation.
[0108]
And even if it is the roll of the other aspect of this invention obtained using polyisocyanate [(b ') component] instead of the said blocked isocyanate [(b) component], the active hydrogen group on the roll surface is reduced. And the entire surface layer is in a crosslinked state. Therefore, the roll of this aspect does not cause toner filming and has excellent durability.
[Brief description of the drawings]
FIG. 1 is a cross-sectional view showing an example of a method for producing a roll according to the present invention.
FIG. 2 is a cross-sectional view showing an example of a roll of the present invention.
FIG. 3 is an explanatory diagram for explaining a method of measuring electrical resistance.
FIG. 4 is an explanatory diagram for explaining a method of measuring electrical resistance.
FIG. 5 is an explanatory diagram for explaining a method of measuring a friction coefficient.
FIG. 6 is an explanatory diagram for explaining a toner charge amount measuring method;
FIG. 7 is an explanatory diagram for explaining a copying mechanism of an electrophotographic copying machine.
FIG. 8 is an explanatory diagram for explaining a copying mechanism of an electrophotographic copying machine.
[Explanation of symbols]
16 roll base
17 Surface layer
18 Low hardness conductive roll

Claims (4)

A roll base having a shaft body is prepared, and a conductive agent is used together with the following components (a) and (b) so that the NCO / active hydrogen ratio is an equivalent ratio of NCO / active hydrogen = 2.5 to 35. Preparing a surface layer forming solution blended with the above, a step of coating the surface layer forming solution on the outer periphery of the roll base, and heat-treating the roll base coated with the surface layer forming solution Thus, a surface layer is formed on the outer periphery of the roll base, the block of the component (b) is removed, and the isocyanate group and the hydroxyl group or amino group of the component (a) are reacted to convert the component (a) into the component (b). A method for producing a low-hardness conductive roll, comprising a step of crosslinking with a component.
(A) A solvent-soluble polymer having a hydroxyl group or an amino group.
(B) Blocked isocyanate. A roll substrate having a shaft body is prepared, and the NCO / active hydrogen ratio is equivalent to the NCO / active hydrogen = 2.5 to 35 in the range of 2.5 to 35, together with the following components (a) and (b ′). A step of preparing a solution for forming a surface layer containing an agent , a step of coating the solution for forming a surface layer on the outer periphery of the roll substrate, and a heat treatment of the roll substrate coated with the solution for forming a surface layer As a result, a surface layer is formed on the outer periphery of the roll base, and the isocyanate group of the component (b ′) is reacted with the hydroxyl group or amino group of the component (a) to convert the component (a) into the component (b ′). And a cross-linking step. A method for producing a low hardness conductive roll.
(A) A solvent-soluble polymer having a hydroxyl group or an amino group.
(B ') Polyisocyanate. The method for producing a low-hardness conductive roll according to claim 1 or 2, wherein the component (a) is at least one selected from the group consisting of the following components (a ₁ ).
(A ₁₎ a thermoplastic polyurethane, silicone-modified urethane, silicone graft acrylic polymer, an acrylic polyol.   The manufacturing method of the low-hardness conductive roll of any one of Claims 1-3 with which the temperature of the said heat processing is set to the range of 130-250 degreeC.

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