JP3922709B2 - Electrostatic latent image developing carrier, electrostatic latent image developer, and process cartridge - Google Patents

Description

【００１６】
アミノシランカップリング剤の含有量は好ましくは、最表層を形成する樹脂中の０．１％以上２０％以下であり、好ましくは０．５％〜１０％である。０．１％以下では帯電性が環境影響を受けやすくなり、２０％を超える場合、微粉体表面との接着性が低下する。
【００１７】
被覆層の充分な硬化を行なうために、酸性下で加温することが好ましいが、用いる酸触媒としては沸点が１００℃以上の有機物の固体酸をコート剤溶液に含有させることが好ましい。触媒の沸点が１００℃未満では、被覆層乾燥時に触媒の蒸発を伴い、架橋形成のための追加熱によって被覆層の硬化が充分に行なうことができない。中でも二塩基酸以上の多価カルボン酸化合物は好ましく用いられる。
酸触媒の例としては、乳酸、ラウリン酸、クロトン酸、コハク酸、グルタール酸、アジピン酸、ピメリン酸、アゼライン酸、セバチン酸、シュウ酸、コハク酸、グリコール酸、マロン酸、マレイン酸、イタコン酸、酒石酸、安息香酸、フタル酸、トリメリット酸、ベンジルスルホン酸、トルエンスルホン酸などの代表的な有機酸、塩酸、硫酸、硝酸、次亜燐酸等の無機酸などを単独、もしくは、混合して用いることができるが、先の架橋反応を適切に進めるためには、少なくとも１種類の酸触媒が１００℃以上の沸点を持つ固体の有機酸を含むものを用いればよい。
【００１８】
ここでいう反応可能な樹脂とは、ポリアミド中に有するメトキシ基との縮合反応性を有するアルコール、アルキロール、カルボン酸や、活性水素を有するアミノ基などを有する樹脂をいう。代表的には熱硬化性を示す樹脂が用いられる。中でも、シリコーン樹脂はその被覆層強度とともに、得られる被覆層の表面エネルギーが低いことから、キャリアにトナーが付着、汚染する、いわゆるスペント性の抑制効果もあり、好ましく用いられる。用いるシリコーン樹脂としては、シラノール基を有するシリコーン樹脂が用いられる。加熱によるシラノール基とポリアミドのメトキシ基間の架橋とともに、ポリアミドの触媒として用いる有機酸とのエステルが生成し、残留の酸触媒による帯電性の負極性化が抑制される。被覆層の帯電量制御、および被覆層強度の向上の目的で、他の架橋型樹脂を混合させることも可能である。なかでもヘキサメチロールメラミン、テトラメチロールベンゾグアナミンに代表される、各種のアルキロールメラミン、およびそのアルキルエーテルなどの誘導体は、被覆層強度と高い帯電量とを同時に得られるため、好ましく用いられる。被覆層強度の向上の目的で、微量のフェノール樹脂を含有させることも好ましい。フェノール樹脂の含有量は好ましくは、最表層を形成する樹脂中の２％以上１０％以下であり、好ましくは４％〜８％である。２％未満では被覆層強度の向上効果が得られず、１０％を超える場合、フェノールの負帯電性により、経時的な帯電性の低下が見られる。
【００１９】
本発明に用いるアルコキシアルキル化ポリアミドは、非架橋状態ではその電気抵抗が低いため、画像形成時に地肌汚れや現像剤の帯電量の放置低下、温湿度による帯電量の変動などの不具合があるため、シリコーン樹脂との架橋構造を形成するための加熱工程により、残留するメトキシ成分を充分に分解する必要がある。こうして得られるキャリアの電気抵抗率は５０Ｖ／ｍｍにおけるＬｏｇＲが１４以上１７以下であり、２５０Ｖ／ｍｍにおける電気抵抗率のＬｏｇＲが８以上１６以下が好ましい範囲である。５０Ｖ／ｍｍにおける電気抵抗率のＬｏｇＲが１４より小さいと放置時の帯電量低下が大きく、また、温湿度による帯電量の変動が大きい。また、２５０Ｖ／ｍｍにおける電気抵抗率のＬｏｇＲが１６より大きいと、連続印刷時にキャリアのチャージアップによる画像濃度の低下が生じ好ましくない。
【００２０】
キャリアの電気抵抗を適正にするために、キャリア被覆層中に導電性物質を含有させることが可能である。ここでいう導電性物質とは、公知の導電性材料を用いることができる。導電性物質の例としては例えば、導電性ＺｎＯ、Ａｌ等の金属粉、各種の方法で作られたＳｎＯ_２及び種々の元素をドープしたＳｎＯ_２、ホウ化物、例えばＴｌＢ_２、ＺｎＢ_２、ＭｏＢ_２、炭化ケイ素及び導電性高分子（ポリアセチレン、ポリパラフェニレン、ポリ（パラ−フェニレンスルフィド）、ポリピロール）などがあるが、最も好ましくは導電性のカーボンブラックである。なかでも、カーボンブラックは広範囲に抵抗値を得られるために好ましく用いられる。
【００２１】
また、先に記述したように、被覆層の補強の目的で被覆層中に他の硬質な微粒成分を含有させることができる。これらは、０．０１〜２０μｍの粒径、好ましくは０．０１〜１０μｍの粒径を有するモース硬度２以上の微粒成分であり得る。なかでも金属酸化物、無機酸化物粒子は均一な粒子径で、かつ被覆層の成分であるポリアミドと高い親和性が得られ、著しい被覆層の補強効果を示すため、好ましく用いられる。
こうした微粒子としては、従来公知の材料を単独、もしくは、混合して用いることが可能であり、代表的にはシリカ、酸化チタン、アルミナなどがある。
被覆層中に含有させる硬質微粒子の含有量として５％〜７０％が好ましく、より好ましくは２〜４０％の範囲である。含有量は用いる微粒子の粒子径、比表面積によって、適切に選ばれるが、５％未満では被覆層の耐磨耗効果が発現しにくく、７０％を超えると、微粒子の脱離が生じやすくなる。
【００２２】
本発明で使用することができるキャリア芯材は、重量平均粒径１０〜１００μｍであって、例えば、鉄、コバルトなどの強磁性体、マグネタイト、ヘマタイト、Ｌｉ系フェライト、Ｍｎ−Ｚｎ系フェライト、Ｃｕ−Ｚｎ系フェライト、Ｎｉ−Ｚｎフェライト、Ｂａフェライトなどの従来より公知のものが使用できる。本発明の被覆樹脂の形成方法はスプレードライ法、浸漬法、あるいはパウダーコーティング法など公知の方法が使用できる。
【００２３】
本発明に使用されるトナーとしては、バインダー樹脂としての熱可塑性樹脂を主成分とし、着色剤、微粒子、そして帯電制御剤、離型剤等を含むものである。また、一般公知の粉砕法、重合法等の各種のトナー製法により作製されたトナーを用いることができる。
【００２４】
バインダー樹脂としては、ポリスチレン、ポリビニルトルエン等のスチレン及びその置換体の単重合体、スチレン−ｐ−クロルスチレン共重合体、スチレン−プロピレン共重合体、スチレン−ビニルトルエン共重合体、スチレン−アクリル酸メチル共重合体、スチレン−アクリル酸エチル共重合体、スチレン−アクリル酸ブチル共重合体、スチレン−メタアクリル酸メチル共重合体、スチレン−メタアクリル酸エチル共重合体、スチレン−メタアクリル酸ブチル共重合体、スチレン−ｏ−クロルアクリル酸メチル共重合体、スチレン−アクリロニトリル共重合体、スチレン−ビニルメチルエーテル共重合体、スチレン−ビニルメチルケトン共重合体、スチレン−ブタジエン共重合体、スチレン−イソブチレン共重合体、スチレン−マレイン酸共重合体、スチレン−マレイン酸エステル共重合体等のスチレン系共重合体、ポリメチルメタクリレート、ポリブチルメタクリレート、ポリ塩化ビニル、ポリ酢酸ビニル、ポリエチレン、ポリプロピレン、ポリエステル、ポリウレタン、エポキシ樹脂、ポリビニルブチラール、ポリアクリル酸樹脂、ロジン、変性ロジン、テルペン樹脂、フェノール樹脂、脂肪族または芳香族炭化水素樹脂、芳香族系石油樹脂、塩素化パラフィン、パラフィンワックスなどが単独あるいは混合して使用できる。
【００２５】
ポリエステル樹脂としては、アルコールと酸との重縮合反応によって得られ、例えばアルコールとしては、ポリエチレングリコール、ジエチルグリコール、トリエチレングリコール、１，２−プロピレングリコール、１，３−プロピレングリコール、１，４−プロピレングリコール、ネオペンチルグリコール、１，４−ブテンジオールなどのジオール類、１，４−ビス（ヒドロキシメチル）シクロヘキサン、ビスフェノールＡ、水素添加ビスフェノールＡ、ポリオキシエチレン化ビスフェノールＡ、ポリオキシプロピレン化ビスフェノールＡなどのエーテル化ビスフェノール類、これらを炭素数３〜２２の飽和もしくは不飽和の炭化水素基で置換した２価のアルコール単量体、その他の２価のアルコール単量体、ソルビトール、１，２，３，６−ヘキサンテトロール、１，４−サルビタン、ペンタエリスリトール、ジペンタエリスリトール、トリペンタエリスリトール、ショ糖、１，２，４−ブタントリオール、１，２，５−ペンタントリオール、グリセロール、２−メチルプロパントリオール、２−メチル−１，２，４−ブタントリオール、トリメチロールエタン、トリメチロールプロパン、１，３，５−トリヒドロキシメチルベンゼン等の３価以上の高級アルコール単量体を挙げることができる。また、ポリエステル樹脂を得るために用いられるカルボン酸としては、例えばパルミチン酸、ステアリン酸、オレイン酸等のモノカルボン酸、マレイン酸、フマール酸、メサコン酸、シトラコン酸、テレフタル酸、シクロヘキサンジカルボン酸、コハク酸、アジピン酸、セバチン酸、マロン酸、これらを炭素数３〜２２の飽和もしくは不飽和の炭化水素基で置換した２価の有機酸単量体、これらの酸の無水物、低級アルキルエステルとリノレイン酸からの二量体、１，２，４−ベンゼントリカルボン酸、１，２，５−ベンゼントリカルボン酸、２，５，７−ナフタレントリカルボン酸、１，２，４−ナフタレントリカルボン酸、１，２，４−ブタントリカルボン酸、１，２，５−ヘキサントリカルボン酸、１，３−ジカルボン酸−２−メチル−２−メチレンカルボキシプロパン、テトラ（メチレンカルボキシル）メタン、１，２，７，８−オクタンテトラカルボン酸エンボール三量体、これらの酸の無水物等の３価以上の多価カルボン酸単量体を挙げることができる。
【００２６】
さらにエポキシ樹脂としては、ビスフェノールＡとエピクロルヒドリンとの重縮合物等があり、例えば、エポミックＲ３６２、Ｒ３６４、Ｒ３６５、Ｒ３６６、Ｒ３６７、Ｒ３６９（以上、三井石油化学工業社製）、エポトートＹＤ−０１１、ＹＤ−０１４、ＹＤ−９０４、ＹＤ−０１７（以上、東都化成社製）、エポコート１００２、１００４、１００７（以上、シェル化学社製）等の市販のものがある。
【００２７】
着色剤としては、カーボンブラック、ランプブラック、鉄黒、群青、ニグロシン染料、アニリンブルー、フタロシアニンブルー、ハンザイエローＧ、ローダミン６Ｇレーキ、カルコオイルブルー、クロムイエロー、キナクリドン、ベンジジンイエロー、ローズベンガル、トリアリルメタン系染料、モノアゾ系、ジスアゾ系、染顔料など、従来公知の染顔料を単独あるいは混合して使用し得る。
【００２８】
また、トナーは、通常使用されるトナーと同様に摩擦帯電性を制御する目的で含有せしめる薬剤を含有していても何ら不都合はない。そうした、いわゆる極性制御剤としては、例えばモノアゾ染料の金属錯塩、ニトロフミン酸及びその塩、サリチル酸、ナフトエ酸、ジカルボン酸のＣｏ、Ｃｒ、Ｆｅ、Ｚｎ等の金属錯体等を単独または混合して用いることができるが、これらに限定されるものではない。カラートナーに使用される極性制御剤は無色であることが必要であり、極性を有するポリマー型の極性制御性物質は好ましく用いられる。
【００２９】
本発明に使用されるトナーには流動性改質剤を添加することができる。流動性改質剤の例としては、有機樹脂微粒子、金属石鹸など、ポリテトラフロロエチレン系フッ素樹脂、ステアリン酸亜鉛のごとき滑剤、或いは酸価セリウム、炭化ケイ素などの研磨剤、一般に流動性改質の目的に用いられる公知の金属酸化物、代表的には酸化ケイ素、酸化チタン、酸化アルミニウムなどの酸化金属微粒子、およびその表面を疎水化した粒子などである。これらのいずれの微粉末もその表面を疎水化することは流動性の面で優れた効果をもたらす。表面を疎水化処理するためには、例えば、シランカップリング剤やシリル化剤として一般に知られる珪素化合物を粒子表面と接触、反応させることができる。
【００３０】
疎水化剤としては例えばクロロシラン類としては代表的にトリクロロシラン、メチルジクロロシラン、ジメチルジクロロシラン、トリメチルクロロシラン、エチルジクロロシラン、ジエチルクロロシラン、トリエチルクロロシラン、プロピルジクロロシラン、ジプロピルジクロロシラン、トリプロピルクロロシランなどアルキルクロロシラン、フェニルクロロシランなど。そのフッソ置換体としてフルオロアルキルクロロシラン、パーフルオロアルキルクロロシランの類。シリルアミン類としては、代表的にヘキサメチルジシラザン、ジエチルアミノトリメチルシラン、ジエチルアミノトリメチルシランなど。シリルアミド類としては、代表的にＮ，Ｏ−ビストリメチルシリルアセトアミド、Ｎ−トリメチルシリルアセトアミド、ビストリメチルシリルトリフルオロアセトアミドなど。また、アルコキシシラン類として、メチルトリアルコキシシラン、ジメチルジアルコキシシラン、トリメチルアルコキシシラン、エチルジアルコキシシラン、ジエチルアルコキシシラン、トリエチルアルコキシシラン、プロピルトリアルコキシシラン、ジプロピルジアルコキシシラン、トリプロピルアルコキシシランなど、アルキルクロロシランや、フェニル基を有するフェニルアルコキシシランなど。また、そのフッソ置換体としてフルオロアルキルアルコキシシランの類、パーフルオロアルキルアルコキシシランの類、シリコーンオイルとして、ジメチルシリコーンオイル、およびその誘導体、フッ素置換体、ジシロキサン、ヘキサメチルジシロキサンなどシロキサンの類など、一般公知の疎水化剤として用いられ化合物が使用できる。
【００３１】
【実施例】
以下、本発明を実施例により具体的に説明する。なお、本発明はここに例示される実施例に限定されるものではない。
＜製造例＞
（製造例１）
メトキシメチル化ポリアミド（ナガセケムテック株式会社製、ＥＦ３０Ｔ）１０部、シラノール含有メチルシリコーン樹脂（ＳｉＯＨ含有量１重量％、ＭＷ１５０００）の固形分濃度２０ｗｔ％トルエン溶液を固形分量１０部相当とを混合、溶解し、さらに酢酸を用いてｐＨ４とし、５０℃にて３時間還流した。この溶液の固形分量に対して、３−（２−アミノエチルアミノプロピル）トリメトキシシランを１部加え、さらにカーボンブラック（ＢＰ２０００）５部、メタノール８０部、アセトン８０部、トルエン８０部にて希釈した液体をホモジナイザーで攪拌、分散して、コート液を得た。この液体の固形分に対して５部のクエン酸を溶解し、流動床乾燥装置にてフェライト芯材（重量平均粒径３５μｍ）に対して塗布し、ナイロン−シリコーン樹脂混合被覆層を設けた。得られた粉体は、２１０℃にて２時間加熱乾燥し、被覆層厚さ０．６μｍのキャリアＡを得た。
上記キャリア抵抗率は、次の方法により、測定することができる。
図１に示すように、電極間距離２ｍｍ、表面積２×４ｃｍの一対の平行平板電極（１２ａ）、（１２ｂ）を収容したフッ素樹脂製容器からなるセル（１１）にキャリア（１３）を充填し、両極間に１００Ｖの直流電圧を印加し、ハイレジスタンスメーター４３２９Ａ（横川ヒューレットパッカード株式会社製）にて直流抵抗を測定し、電気抵抗率ＬｏｇＲ・Ωｃｍを算出する。印加電圧は１００Ｖおよび５００Ｖにおける抵抗率を測定した。
このキャリアの電気抵抗率のＬｏｇＲは１４．５Ωｃｍ（５０Ｖ／ｍｍ）、１３．２Ωｃｍ（２５０Ｖ／ｍｍ）であった。
また、キャリアの収率は、目開き６３μｍのメッシュふるいに作成したキャリアを入れ、これを振動式篩分け器にかけて篩分けし、メッシュを通過したものの割合を測定した。
このキャリアの収率は、８６％であった。
【００３２】
（製造例２）
製造例１において、３−アミノプロピルトリエトキシシランとすること以外は、すべて同様にしてキャリアＢを得た。このキャリアの電気抵抗率のＬｏｇＲは１４．６Ωｃｍ（５０Ｖ／ｍｍ）、１３．６Ωｃｍ（２５０Ｖ／ｍｍ）であった。また、このキャリアの収率は、８４％であった。
【００３３】
（製造例３）
製造例１において、ジブチルアミノプロピルトリメトキシシランとすること以外は全て同様にしてキャリアＣを得た。このキャリアの電気抵抗率のＬｏｇＲは１４．１Ωｃｍ（５０Ｖ／ｍｍ）、１３．８Ωｃｍ（２５０Ｖ／ｍｍ）であった。また、このキャリアの収率は、７７％であった。
【００３４】
（製造例４）
製造例１において、用いるシリコーン樹脂をＳｉＯＨ含有量６重量％、分子量ＭＷ５０００のメチルフェニルシリコーン樹脂とする以外はすべて同様にして被覆層厚さ０．６μｍのキャリアＤを得た。このキャリアの電気抵抗率のＬｏｇＲは１４．２Ωｃｍ（５０Ｖ／ｍｍ）、１３．１Ωｃｍ（２５０Ｖ／ｍｍ）であった。また、このキャリアの収率は８５％であった。
【００３５】
（製造例５）
製造例４において、メトキシメチル化ポリアミド固形分７部、シラノール型メチルフェニルシリコーン樹脂の固形分１３部とする以外は全て同様にしてキャリアＥを得た。このキャリアの電気抵抗率のＬｏｇＲは１５．２Ωｃｍ（５０Ｖ／ｍｍ）、１４．６Ωｃｍ（２５０Ｖ／ｍｍ）であった。また、キャリアの収率は、８６％であった。
【００３６】
（製造例６）
製造例４において、メトキシメチル化ポリアミド固形分１３部、シラノール型メチルフェニルシリコーン樹脂の固形分７部とする以外は全て同様にしてキャリアＦを得た。このキャリアの電気抵抗率のＬｏｇＲは１４．０Ωｃｍ（５０Ｖ／ｍｍ）、１３．０Ωｃｍ（２５０Ｖ／ｍｍ）であった。また、このキャリアの収率は８４％であった。
【００３７】
（製造例７）
製造例４において、さらにヘキサブトキシメチル化メラミン、トルエン、ブタノール混合溶液の固形分量２部相当を添加し、同様に被覆層を形成してキャリア粒子Ｇを得た。このキャリアの電気抵抗率のＬｏｇＲは１４．６Ωｃｍ（５０Ｖ／ｍｍ）、１３．３Ωｃｍ（２５０Ｖ／ｍｍ）であった。また、このキャリアの収率は８４％であった。
【００３８】
（製造例８）
製造例４において、さらにテトラブトキシメチル化ベンゾグアナミンのトルエン、ブタノール混合溶液の固形分量２部相当を添加し、同様に被覆層を形成してキャリア粒子Ｈを得た。このキャリアの電気抵抗率のＬｏｇＲは１５．２Ωｃｍ（５０Ｖ／ｍｍ）、１３．９Ωｃｍ（２５０Ｖ／ｍｍ）であった。また、このキャリアの収率は８８％であった。
【００３９】
（製造例９）
製造例６において、クエン酸に代えてアジピン酸を用いる以外はすべて同様にしてキャリアＩを得た。このキャリアの電気抵抗率のＬｏｇＲは１４．５Ωｃｍ（５０Ｖ／ｍｍ）、１３．９Ωｃｍ（２５０Ｖ／ｍｍ）であった。またこのキャリアの収率は８４％であった。
【００４０】
（製造例１０）
製造例７において、コート液に疎水性シリカＲ９７２を樹脂固形分に対し２部添加し、ホモジナイザーで２０分間分散して得られたコート液を用いて、被覆層を形成する以外はすべて同様にしてキャリアＪを得た。このキャリアの電気抵抗率のＬｏｇＲは１４．６Ωｃｍ（５０Ｖ／ｍｍ）、１４．３Ωｃｍ（２５０Ｖ／ｍｍ）であった。また、このキャリアの収率は８７％であった。
【００４１】
（製造例１１）
製造例８において、コート液にさらに粒子径０．３ミクロンのアルミナ微粒子を樹脂固形分に対し１部添加し、これをホモジナイザーで同様に分散して得られたコート液を用い、被覆層を形成する以外はすべて同様にしてキャリアＫを得た。このキャリアの電気抵抗率のＬｏｇＲは１５．４Ωｃｍ（５０Ｖ／ｍｍ）、１３．６Ωｃｍ（２５０Ｖ／ｍｍ）であった。またこのキャリアの収率は８８％であった。
【００４２】
（製造例１２）
製造例１において、３−（２−アミノエチルアミノプロピル）トリメトキシシランを用いないこと以外は、すべて同様にしてキャリアＬを得た。このキャリアの電気抵抗率のＬｏｇＲは１４．０Ωｃｍ（５０Ｖ／ｍｍ）、１３．５Ωｃｍ（２５０Ｖ／ｍｍ）であった。また、このキャリアの収率は５６％であった。
【００４３】
（製造例１３）
製造例１において、シリコーン樹脂を用いない以外はすべて同様にしてキャリアＭを得た。このキャリアの電気抵抗率のＬｏｇＲは１３．６Ωｃｍ（５０Ｖ／ｍｍ）、１２．４Ωｃｍ（２５０Ｖ／ｍｍ）であった。またこのキャリアの収率は６２％であった。
【００４４】
（製造例１４）
製造例１において、２００℃での追加熱をせずに、キャリア粒子を得た。このキャリアＮの電気抵抗率のＬｏｇＲは９．８Ωｃｍ（５０Ｖ／ｍｍ）、８．５Ωｃｍ（２５０Ｖ／ｍｍ）であった。またこのキャリアの収率は８７％であった。
【００４５】
（製造例１５）
メトキシメチル化ポリアミド（ナガセケムテック株式会社製、ＥＦ３０Ｔ）１０部、レゾール型フェノール樹脂（住友ベークライト、ＰＲ５１２８３）の固形分２部をメタノール８０部に溶解し、さらに酢酸を用いてｐＨ４とし、５０℃にて３時間還流した。この溶液の固形分量に対して、３−（２−アミノエチルアミノプロピル）トリメトキシシランを１部加え、さらにカーボンブラック（ＢＰ２０００）５部、疎水性シリカ微粒子（Ｒ９７２５部、日本アエロジル社）を加え、さらに、メタノール８０部、アセトン８０部で希釈た液体をホモジナイザーで攪拌、分散して、コート液を得た。以下、製造例１と同様にしてキャリアＯを得た。このキャリアの電気抵抗率のＬｏｇＲは１３．７Ωｃｍ（５０Ｖ／ｍｍ）、１２．９Ωｃｍ（２５０Ｖ／ｍｍ）であった。またこのキャリアの収率は８２％であった。
【００４６】
［実施例１］
製造例１で作成したキャリアＡ９３部とＩＰＳＩＯ Ｃｏｌｏｒ８０００用黒トナー７部を混合し、現像剤とし、これをＩＰＳＩＯ Ｃｏｌｏｒ８０００に装填して、画像面積率１２％、文字画像チャートを用いて１０万枚の連続プリント試験を行なった。
試験開始時、および、連続プリント終了時の現像剤を少量抜き出し、この現像剤中のキャリアの帯電量を測定した。また、１０万枚プリント終了時の画像の地肌汚れ、現像剤の帯電量を同様に評価した。
現像剤の帯電量は、現像装置のスリーブ上から少量の現像剤を採取し、公知のブローオフ法に基づいて行なった。
キャリアの膜厚の測定は、キャリアを破砕し、走査型電子顕微鏡で観察して求めた。
地肌汚れの評価は目視評価で４段階の評価とした。
被覆層均一性は、ＳＥＭ観察像から目視評価し、４段階で評価した。
スペント量は、現像剤から分離したキャリア１ｇをＭＥＫ、トルエンの１：１混合溶液１０ｇに溶解し、その上澄み液を分光光度計にて３２０ｎｍ〜７００ｎｍの吸光度を測定し、その平均の吸光度を評価した。
評価結果を表２に示す。表中記載の記号は◎：大変良好、○：良好、△：若干不良、×：不良（×は許容不可のレベル）とした。
【００４７】
［実施例２〜１１、比較例１〜４］
実施例１においてキャリアＡに換えてキャリアＢ〜Ｏをそれぞれ用いて（表１参照）、同様に現像剤とし、画像評価を行なった。結果を同様に表２に示す。
【００４８】
【表２−１】

【００４９】
【表２−２】

【００５０】
【発明の効果】
以上、詳細かつ具体的な説明より明らかなように、本発明によると被覆層のアルコキシアルキル化ポリアミドおよびそれと相互に反応性を有する樹脂を用いた被覆層を設けたキャリアによって、被覆層の帯電性、磨耗性に優れたキャリアが提供される。さらに、用いる樹脂をシラノール基を有するシリコーン樹脂とし、アミノシランカップリング剤を加え、コート後の加温工程で触媒を作用させることにより、帯電の耐久性、使用環境による変化を低減することが可能となり、信頼性に優れ、さらに生産性向上が可能なキャリアを提供できるという優れた効果を奏する。
【図面の簡単な説明】
【図１】本発明の製造例で用いたキャリアの抵抗率を測定した装置である。
【符号の説明】
１１ セル
１２ａ 電極
１２ｂ 電極
１３ キャリア[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a carrier for developing an electrostatic latent image used in a two-component developer used in electrophotography and electrostatic recording, an electrostatic latent image developer using the carrier, and a process cartridge.
[0002]
[Prior art]
In recent years, printing apparatuses using an electrophotographic system have been rapidly colorized and the printing speed has been increased.
Conventionally, the two-component development method is suitable for high-speed printing and has been widely used in full-color image forming apparatuses because non-magnetic toner is easy to handle. However, the full-color printing apparatus needs to have a plurality of developing devices in the apparatus, and there are drawbacks such as an increase in the size and weight of the apparatus as compared with a monochrome machine. In particular, the two-component developing device needs to be equipped with a developer storage volume and a stirring mechanism in addition to the toner as compared with the one-component developing device. To reduce the size of the developing unit, a small amount of developer is required. It was essential.
[0003]
The carrier in the developer is repeatedly subjected to mechanical friction and impact in the developing device by friction with toner, a rubbing member such as a sleeve and a blade, a regulating member and a stirring and conveying member such as a screw and paddle. Decreasing the amount of developer means an increase in the chance of friction between the toner and the carrier per the number of printed sheets and an increase in the frequency of the carrier passing through the developing portion. As a result, the fatigue of the carrier in the developing unit rapidly proceeds. . Combined with higher printing speed, the durability of the carrier, especially the high wear resistance of the coating layer on the surface of the carrier, and the contamination of the carrier surface with toner and other components (spent) can be prevented, and over a long period of time, Maintaining charging properties has become more important than ever.
[0004]
In recent digital copying machines and printers, negative-positive development is often performed using a negatively charged photoconductor, and negatively charged toner is often used. Many examples are known in which an organic compound containing nitrogen is contained in the carrier coating layer in order to negatively charge the toner.
For example, an example of using an aminosilane coupling agent mixed with a silicone resin, an example of internally adding a certain type of acid amide, a method of internally adding an amino compound such as melamine or guanamine or a derivative thereof, an acrylic group having an amino group For example, a copolymer is used for the coating layer.
As an example of using such a nitrogen-containing organic material as a coating material, an example of using polyamide has been conventionally disclosed (for example, Patent Document 1).
However, polyamide resins typified by nylon are generally preferred materials for imparting negative chargeability to toners, but many of them are poor in solvent solubility, so that layers can be formed by a simple method such as applying a solution. There are also problems such as being difficult to do and insufficient wear resistance of the polyamide itself.
[0005]
Therefore, examples of using polyamides in a solvent solubilized are disclosed in which hydrogen atoms of amide bonds are alkoxylated and alkoxyalkylated (for example, Patent Documents 2 to 6), and graft polymers having such polyamides in the main chain are disclosed. (For example, refer to Patent Documents 7 and 8), however, a coating layer using such a polyamide as a main component has not been sufficient in the wear resistance of the coating layer.
Moreover, it is shown that N-methoxymethylated polyamide is used and the surface resistance is 13 Ω · cm or less, and the resistance of the coating layer is lowered by partially methoxymethylating the polyamide. (See, for example, Patent Document 9), the reduction in carrier resistance due to residual methoxy groups is brought about by the high water affinity of methoxy groups. There was a problem such as a large decrease in storage.
In order to solve these problems, N-alkoxyalkylated polyamide and at least one kind of resin capable of reacting with the N-alkoxyalkylated polyamide resin containing silicone having at least a silanol group and / or a hydrolyzable group are provided. Although the coating agent to be contained has been studied, there has been a problem that the carriers are likely to agglomerate during coating and the product yield of the coated product is poor.
[0006]
[Patent Document 1]
JP-A-49-115549 (Claims on page 1, lower left column, lines 3 to 6; page 2, upper right column, line 19 to lower left column, line 16)
[Patent Document 2]
Japanese Patent Laid-Open No. 1-118150 (1st page, lower left column, line 4 to end line)
[Patent Document 3]
Japanese Patent Application Laid-Open No. 1-1118151 (claim 1 in the first page, lower left column, fourth line to upper right column, first line)
[Patent Document 4]
Japanese Patent Laid-Open No. 4-188160 (1st page, lower left column, claims 4-7), 3rd page, upper right column, 6th-12th line, 3rd page, lower right column 4th to 14th lines)
[Patent Document 5]
JP 2001-201894 A (2nd page, first column, line 1 to line 45)
[Patent Document 6]
Japanese Patent No. 3443390 (1st page, 1st column, 1st line to 9th line, claim 1, 3rd page, 5th column, 8th line to 13th line, 3rd page, 6th column, 2nd page) (Lines 8 to 8, page 3, column 6, lines 19 to 34)
[Patent Document 7]
Japanese Patent No. 2835971 (Claims on page 1, column 1, line 1 to page 2, line 11; page 3, column 5, line 41 to page 4, column 7, line 7, line 22) Eye)
[Patent Document 8]
Japanese Patent No. 2835972 (Claims on page 1, column 1, line 1 to column 2, line 10), page 3, column 6, lines 13 to 43)
[Patent Document 9]
Japanese Patent No. 0923192 (Claims on page 1, column 1, line 1 to column 2, line 9), page 2, column 4, line 42 to page 3, column 6, column 6, line 7 Eyes, page 3, column 5, line 46 to column 6, line 35)
[0007]
[Problems to be solved by the invention]
An object of the present invention is to solve the above problems. In other words, it has stable charging ability over a long period of time, has excellent wear resistance of the coating layer, excellent adhesion between the magnetic fine powder and the coating layer, high product yield of the coated carrier, toner composition It is an object of the present invention to provide a carrier for developing an electrostatic latent image that is free from fluctuations in charging due to spent of the object. In addition, it suppresses changes in the charging environment and the amount of neglected charge, and there are no problems such as fluctuations in image density, background stains, and in-machine contamination due to toner in various usage environments. The object is to provide a carrier for image development. Another object of the present invention is to provide a developer for an electrostatic latent image using the carrier for developing an electrostatic latent image, and a process cartridge.
[0008]
[Means for Solving the Problems]
In the present invention, the N- alkoxyalkyl polyamides, reacted capable of reacting one or more resins and the N- alkoxyalkylated polyamide resin containing a silicone resin, and amino silane coupling agent having at least silanol groups obtained When the resulting condensate is used as a coating agent, there is no fluctuation in charging due to spent toner composition, and fluctuations in the charging environment and the decrease in the amount of static charge are suppressed. In addition, it is possible to obtain a carrier for developing an electrostatic latent image that is free from defects such as in-machine contamination due to toner and capable of obtaining a high-quality image with a good product yield of a coated product that hardly causes aggregation between carriers during coating. Was found.
Therefore, the above-mentioned problems are solved by (1) “a magnetic core material having a coating layer on the surface thereof (i) an N-alkoxyalkylated polyamide and (ii) a silicone having at least a silanol group. For developing an electrostatic latent image, comprising: one or more resins capable of reacting with the N-alkoxyalkylated polyamide resin including a resin; and (iii) a condensate obtained from a mixture of aminosilane coupling agents. Career ";
(2) "The electrostatic latent image developing carrier according to (1) above, wherein the amino equivalent of the aminosilane coupling agent is 170 to 230";
(3) "The electrostatic latent image developing carrier according to (1) or (2) above, wherein the coating layer contains a solid organic acid having a boiling point of 100 ° C or higher";
(4) "The electrostatic latent image developing carrier according to any one of (1) to (3) above, wherein the coating layer has methylolmelamine";
(5) "The electrostatic latent image developing carrier according to any one of (1) to (4) above, wherein the coating layer contains methylolbenzoguanamine";
(6) LogR in electrical resistivity in the "applied electric field 50 V / mm is not less 14 or more, the first (1), wherein the LogR electrical resistivity at 250V / mm is 16 or less claim to the (5 The carrier for developing an electrostatic latent image according to any one of items 1 ) ;
(7) According to any one of (1) to (6), wherein the coating layer contains a low-resistance substance having a resistivity of 10 ⁻³ to 10 ⁸ Ω · cm. Electrostatic latent image developing carrier ";
(8) The carrier for developing an electrostatic latent image according to item (7), wherein the low-resistance substance is conductive carbon;
(9) "The electrostatic latent image developing carrier according to any one of (1) to (8) above, wherein the coating layer has hard fine particles";
(10) In the above item (9) , wherein the hard fine particles in the coating layer are metal oxide particles, and the metal oxide particles are any one of Si, Ti, and Al. The electrostatic latent image developing carrier described in the above;
(11) For electrostatic latent image development according to item (10), wherein the content of the metal oxide particles in the coating layer is in the range of 5% to 70% of the weight of the coating layer. Achieved by "career".
[0009]
In addition, the above-described problem is solved by (12) “electrostatic latent image developing carrier and electrostatic latent image developing toner according to any one of (1) to (11 ) ” of the present invention. Latent image developer ";
(13) The electrostatic latent image developer according to item (12) above, wherein the photosensitive member, the charging brush for charging the surface of the photosensitive member, and the electrostatic latent image formed on the surface of the photosensitive member are It is achieved by a “process cartridge” comprising a developing section that is used and developed, and a blade that wipes off the developer remaining on the surface of the photoreceptor.
[0010]
Hereinafter, embodiments of the present invention will be described.
Examples of the polyamide used in the present invention include solvent-solubilized polyamides in which the hydrogen atom of the amide bond of the main chain is alkoxyalkylated. Using this, the polyamide has a lower alcohol solution and is reactive with the polyamide. A coating layer is formed by applying a coating liquid prepared by mixing and dissolving one or a plurality of resins and, if necessary, a catalyst for promoting crosslinking, to a carrier core material having magnetism, drying, and heat curing. The term “polyamide” as used herein refers to a general polyamide obtained from a dicarboxylic acid and a diamine, or a polyamide formed by ring-opening condensation polymerization of various lactams.
For example, as a method for methoxymethylation of polyamide, it is carried out by reacting with formalin in an acidic atmosphere in which polyamide can be dissolved such as formic acid in the presence of a lower alcohol such as methanol.
Since the methoxymethylated polyamide thus obtained has improved solubility in lower alcohols such as methanol according to the reaction ratio, it is easy to form a coating layer on the carrier surface. In addition, the polyamide exhibits rubber elasticity in an uncrosslinked state, and is heated in the presence of an appropriate acid catalyst to condense between the self methoxy group and the active hydrogen of the amide bond of the main chain, Crosslink and increase hardness. This is mixed with a silanol-condensable silicone resin , applied as a carrier coating layer, and similarly heated in the presence of an acid catalyst to form a coating layer having a cross-linked structure between the silicone resin and the polyamide.
[0011]
In the present invention, the coating layer strength is further strengthened by mixing the metal oxide particles in the coating layer. For example, the metal oxide particles are introduced into the coating layer as follows.
The solubilized polyamide is dissolved in methanol with heating as necessary.
Metal oxide particles are mixed in the dissolved solution and uniformly dispersed using a dispersing device such as a homogenizer.
The dispersion is mixed with a separately prepared non-aqueous solvent solution of a silanol condensable silicone resin , and similarly stirred with a homogenizer, and a charge adjusting agent and a resistance adjusting agent are mixed appropriately and applied to the carrier core material.
[0012]
Here, examples of polyamides used in the present invention include, for example, 1,6-hexanediamine, 1,8-octadiamine, linear alkyldiamine such as 1,2-propanediamine, branched alkyldiamine, Examples of aromatic diamines such as m-phenylenediamine, P-phenylenediamine, o-phenylenediamine, toluene-2,5-diamine, N-phenyl-p-phenyldiamine, and 4,4-diaminodiphenylamine, and carboxylic acids include , Maleic acid, fumaric acid, mesaconic acid, citraconic acid, terephthalic acid, isophthalic acid, cyclohexanedicarboxylic acid, succinic acid, adipic acid, sebacic acid, dodecanoic acid, malonic acid and other polyhydric fatty acids, aromatic dicarboxylic acids, various A condensation polymer such as an amino acid, Styrenesulfonate, also amino self condensation polymer such as a ring-opening polycondensation or aminoundecanoic acid various caprolactam, and the like thereof mutual copolymers.
[0013]
The alkylalkoxylation treatment for solubilizing the polyamide is preferably about 20 to 70 mol% in terms of the substitution rate of active hydrogen of the amide bond. When the amount is less than this, the alcohol solubility is poor, and there are problems such as precipitation during the formation of the coating layer and segregation after the formation of the coating layer. When it is more than 70%, the coating layer density is lowered and the wear resistance is deteriorated. The same applies to the case where metal oxide particles are added.
[0014]
The aminosilane coupling agent used in the present invention is a silane coupling agent containing any of primary, secondary and tertiary amino groups. Furthermore, the amino equivalent of the aminosilane coupling agent is preferably 170-230. The amino equivalent referred to here is a value obtained by dividing the molecular weight of the aminosilane coupling agent by the number of nitrogen elements contained in the aminosilane coupling agent. By using an aminosilane coupling agent having an amino equivalent of 170 or more, the decrease in charge amount due to running is further improved. In addition, when the amino equivalent is large, the amount of addition is increased to obtain a product yield equivalent to that when the amino equivalent is small. Therefore, the amino equivalent is preferably 230 or less. The amino equivalent of the aminosilane coupling agent is desirably 170-230.
Typical aminosilane coupling agents include the following:
[Table 1]

[0016]
The content of the aminosilane coupling agent is preferably 0.1% or more and 20% or less in the resin forming the outermost layer, and preferably 0.5% to 10%. If it is 0.1% or less, the chargeability is easily affected by the environment, and if it exceeds 20%, the adhesion to the surface of the fine powder is lowered.
[0017]
In order to sufficiently cure the coating layer, it is preferable to heat under an acidic condition. However, as the acid catalyst to be used, it is preferable to contain an organic solid acid having a boiling point of 100 ° C. or higher in the coating agent solution. When the boiling point of the catalyst is less than 100 ° C., the catalyst is evaporated when the coating layer is dried, and the coating layer cannot be sufficiently cured by the additional heat for forming a crosslink. Of these, polybasic carboxylic acid compounds having a dibasic acid or higher are preferably used.
Examples of acid catalysts include lactic acid, lauric acid, crotonic acid, succinic acid, glutaric acid, adipic acid, pimelic acid, azelaic acid, sebacic acid, oxalic acid, succinic acid, glycolic acid, malonic acid, maleic acid, itaconic acid , Representative organic acids such as tartaric acid, benzoic acid, phthalic acid, trimellitic acid, benzyl sulfonic acid, toluene sulfonic acid, inorganic acids such as hydrochloric acid, sulfuric acid, nitric acid, hypophosphorous acid, etc. Although it can be used, in order to appropriately advance the above-described crosslinking reaction, it is sufficient to use one in which at least one acid catalyst contains a solid organic acid having a boiling point of 100 ° C. or higher.
[0018]
The resin which can be referred to herein means a resin having an alcohol, an alkylol, a carboxylic acid, an amino group having active hydrogen, or the like having condensation reactivity with a methoxy group in the polyamide. Typically, a thermosetting resin is used. Among them, the silicone resin is preferably used because it has the effect of suppressing the so-called spent property that the toner adheres to and contaminates the carrier since the surface energy of the resulting coating layer is low together with the strength of the coating layer. As the silicone resin used, a silicone resin having a silanol group is used. Along with the crosslinking between the silanol group and the methoxy group of the polyamide by heating, an ester with an organic acid used as a catalyst for the polyamide is generated, and the negative charging property due to the residual acid catalyst is suppressed. For the purpose of controlling the charge amount of the coating layer and improving the strength of the coating layer, it is possible to mix other crosslinkable resins. Among these, various alkylol melamines typified by hexamethylol melamine and tetramethylol benzoguanamine, and derivatives thereof such as alkyl ethers thereof are preferably used because they can provide coating layer strength and high charge amount at the same time. For the purpose of improving the strength of the coating layer, it is also preferable to contain a trace amount of phenol resin. The content of the phenol resin is preferably 2% or more and 10% or less in the resin forming the outermost layer, and preferably 4% to 8%. If the content is less than 2%, the effect of improving the strength of the coating layer cannot be obtained. If the content exceeds 10%, the chargeability with time decreases due to the negative chargeability of phenol.
[0019]
Since the alkoxyalkylated polyamide used in the present invention has a low electrical resistance in the non-crosslinked state, there are problems such as background stains during image formation and a decrease in the charge amount of the developer, and a change in the charge amount due to temperature and humidity. It is necessary to sufficiently decompose the remaining methoxy component by a heating step for forming a crosslinked structure with the silicone resin. The electrical resistivity of the carrier thus obtained is such that LogR at 50 V / mm is 14 or more and 17 or less, and LogR of electrical resistivity at 250 V / mm is 8 or more and 16 or less. If the LogR of electrical resistivity at 50 V / mm is smaller than 14, the charge amount during standing is greatly reduced, and the change in charge amount due to temperature and humidity is large. On the other hand, if the LogR of electrical resistivity at 250 V / mm is larger than 16, image density is lowered due to charge-up of the carrier during continuous printing, which is not preferable.
[0020]
In order to make the electric resistance of the carrier appropriate, a conductive substance can be contained in the carrier coating layer. As the conductive substance here, a known conductive material can be used. Examples of the conductive material, for example, conductive ZnO, metal powder such as Al, SnO ₂ doped with SnO ₂ and various elements made by various methods, borides, eg _{TlB 2,} ZnB _2, MoB 2 , Silicon carbide and conductive polymers (polyacetylene, polyparaphenylene, poly (para-phenylene sulfide), polypyrrole), etc., and most preferably conductive carbon black. Among these, carbon black is preferably used because a resistance value can be obtained over a wide range.
[0021]
Further, as described above, another hard fine particle component can be contained in the coating layer for the purpose of reinforcing the coating layer. These may be fine particle components having a Mohs hardness of 2 or more having a particle size of 0.01 to 20 μm, preferably 0.01 to 10 μm. Among these, metal oxide and inorganic oxide particles are preferably used because they have a uniform particle diameter, high affinity with polyamide as a component of the coating layer, and a remarkable reinforcing effect of the coating layer.
As such fine particles, conventionally known materials can be used alone or in combination, and typically include silica, titanium oxide, alumina and the like.
The content of hard fine particles contained in the coating layer is preferably 5% to 70%, more preferably 2 to 40%. The content is appropriately selected according to the particle diameter and specific surface area of the fine particles to be used, but if it is less than 5%, the wear resistance effect of the coating layer is difficult to be exhibited, and if it exceeds 70%, the particles are likely to be detached.
[0022]
The carrier core material that can be used in the present invention has a weight average particle diameter of 10 to 100 μm, and includes, for example, ferromagnetics such as iron and cobalt, magnetite, hematite, Li-based ferrite, Mn—Zn-based ferrite, Cu Conventionally known ones such as -Zn ferrite, Ni-Zn ferrite and Ba ferrite can be used. As a method for forming the coating resin of the present invention, a known method such as a spray drying method, a dipping method, or a powder coating method can be used.
[0023]
The toner used in the present invention is mainly composed of a thermoplastic resin as a binder resin, and contains a colorant, fine particles, a charge control agent, a release agent and the like. In addition, toners produced by various toner production methods such as generally known pulverization methods and polymerization methods can be used.
[0024]
As binder resin, styrene such as polystyrene and polyvinyltoluene and homopolymers thereof, styrene-p-chlorostyrene copolymer, styrene-propylene copolymer, styrene-vinyltoluene copolymer, styrene-acrylic acid Methyl copolymer, styrene-ethyl acrylate copolymer, styrene-butyl acrylate copolymer, styrene-methyl methacrylate copolymer, styrene-ethyl methacrylate copolymer, styrene-butyl methacrylate copolymer Polymer, styrene-o-chloromethyl acrylate copolymer, styrene-acrylonitrile copolymer, styrene-vinyl methyl ether copolymer, styrene-vinyl methyl ketone copolymer, styrene-butadiene copolymer, styrene-isobutylene Copolymer, styrene-maleic acid Polymer, styrene copolymer such as styrene-maleic acid ester copolymer, polymethyl methacrylate, polybutyl methacrylate, polyvinyl chloride, polyvinyl acetate, polyethylene, polypropylene, polyester, polyurethane, epoxy resin, polyvinyl butyral, poly Acrylic resin, rosin, modified rosin, terpene resin, phenol resin, aliphatic or aromatic hydrocarbon resin, aromatic petroleum resin, chlorinated paraffin, paraffin wax and the like can be used alone or in combination.
[0025]
The polyester resin is obtained by a polycondensation reaction between an alcohol and an acid. Examples of the alcohol include polyethylene glycol, diethyl glycol, triethylene glycol, 1,2-propylene glycol, 1,3-propylene glycol, 1,4- Diols such as propylene glycol, neopentyl glycol, 1,4-butenediol, 1,4-bis (hydroxymethyl) cyclohexane, bisphenol A, hydrogenated bisphenol A, polyoxyethylenated bisphenol A, polyoxypropylenated bisphenol A Etherified bisphenols such as these, divalent alcohol monomers in which these are substituted with a saturated or unsaturated hydrocarbon group having 3 to 22 carbon atoms, other divalent alcohol monomers, sorbitol, 1, 2, 3, -Hexanetetrol, 1,4-sarbitane, pentaerythritol, dipentaerythritol, tripentaerythritol, sucrose, 1,2,4-butanetriol, 1,2,5-pentanetriol, glycerol, 2-methylpropanetriol And trihydric or higher alcohol monomers such as 2-methyl-1,2,4-butanetriol, trimethylolethane, trimethylolpropane and 1,3,5-trihydroxymethylbenzene. Examples of the carboxylic acid used to obtain the polyester resin include monocarboxylic acids such as palmitic acid, stearic acid, and oleic acid, maleic acid, fumaric acid, mesaconic acid, citraconic acid, terephthalic acid, cyclohexanedicarboxylic acid, and succinic acid. Acids, adipic acid, sebacic acid, malonic acid, divalent organic acid monomers in which these are substituted with saturated or unsaturated hydrocarbon groups having 3 to 22 carbon atoms, anhydrides of these acids, lower alkyl esters and Dimer from linolenic acid, 1,2,4-benzenetricarboxylic acid, 1,2,5-benzenetricarboxylic acid, 2,5,7-naphthalenetricarboxylic acid, 1,2,4-naphthalenetricarboxylic acid, 1, 2,4-butanetricarboxylic acid, 1,2,5-hexanetricarboxylic acid, 1,3-dicarboxylic acid-2-methyl A trivalent or higher polyvalent carboxylic acid monomer such as 2-methylenecarboxypropane, tetra (methylenecarboxyl) methane, 1,2,7,8-octanetetracarboxylic acid embol trimer, and anhydrides of these acids; Can be mentioned.
[0026]
Further, examples of the epoxy resin include polycondensates of bisphenol A and epichlorohydrin. For example, Epomic R362, R364, R365, R366, R367, R369 (above, manufactured by Mitsui Petrochemical Co., Ltd.), Epototo YD-011, YD There are commercially available products such as -014, YD-904, YD-017 (above, manufactured by Tohto Kasei Co., Ltd.), Epocoat 1002, 1004, 1007 (above, manufactured by Shell Chemical Co., Ltd.).
[0027]
Colorants include carbon black, lamp black, iron black, ultramarine, nigrosine dye, aniline blue, phthalocyanine blue, Hansa Yellow G, rhodamine 6G lake, calco oil blue, chrome yellow, quinacridone, benzidine yellow, rose bengal, triallyl. Conventional dyes and pigments such as methane dyes, monoazo dyes, disazo dyes, and dyes can be used alone or in combination.
[0028]
Further, the toner does not have any inconvenience even if it contains a drug to be contained for the purpose of controlling the triboelectric chargeability as in the case of the toner that is usually used. As such so-called polarity control agents, for example, metal complexes of monoazo dyes, nitrohumic acid and its salts, metal complexes of salicylic acid, naphthoic acid, dicarboxylic acid such as Co, Cr, Fe, Zn, etc. may be used alone or in combination. However, it is not limited to these. The polarity control agent used in the color toner needs to be colorless, and a polymer type polarity control substance having polarity is preferably used.
[0029]
A fluidity modifier can be added to the toner used in the present invention. Examples of fluidity modifiers include organic resin fine particles, metal soaps, polytetrafluoroethylene fluororesins, lubricants such as zinc stearate, or abrasives such as acid value cerium and silicon carbide, generally fluidity modifiers For example, known metal oxides, typically metal oxide fine particles such as silicon oxide, titanium oxide and aluminum oxide, and particles whose surfaces are hydrophobized. Hydrophobizing the surface of any of these fine powders has an excellent effect in terms of fluidity. In order to hydrophobize the surface, for example, a silicon compound generally known as a silane coupling agent or silylating agent can be brought into contact with and reacted with the particle surface.
[0030]
As the hydrophobizing agent, for example, chlorosilanes typically include trichlorosilane, methyldichlorosilane, dimethyldichlorosilane, trimethylchlorosilane, ethyldichlorosilane, diethylchlorosilane, triethylchlorosilane, propyldichlorosilane, dipropyldichlorosilane, tripropylchlorosilane, etc. Alkylchlorosilane, phenylchlorosilane, etc. Fluoroalkyl chlorosilanes and perfluoroalkyl chlorosilanes as the fluoro-substituted product. Typical examples of silylamines include hexamethyldisilazane, diethylaminotrimethylsilane, and diethylaminotrimethylsilane. Typical examples of silylamides include N, O-bistrimethylsilylacetamide, N-trimethylsilylacetamide, bistrimethylsilyltrifluoroacetamide, and the like. Examples of alkoxysilanes include methyltrialkoxysilane, dimethyldialkoxysilane, trimethylalkoxysilane, ethyldialkoxysilane, diethylalkoxysilane, triethylalkoxysilane, propyltrialkoxysilane, dipropyldialkoxysilane, and tripropylalkoxysilane. Alkylchlorosilane and phenylalkoxysilane having a phenyl group. In addition, fluoroalkyl alkoxysilanes, perfluoroalkylalkoxysilanes as fluorine-substituted products, dimethylsilicone oil and derivatives thereof as silicone oils, fluorine-substituted products, siloxanes such as disiloxane, hexamethyldisiloxane, etc. A compound that can be used as a generally known hydrophobizing agent can be used.
[0031]
【Example】
Hereinafter, the present invention will be specifically described by way of examples. In addition, this invention is not limited to the Example illustrated here.
<Production example>
(Production Example 1)
10 parts of methoxymethylated polyamide (manufactured by Nagase Chemtech Co., Ltd., EF30T), a 20% by weight solid content solution of silanol-containing methylsilicone resin (SiOH content 1% by weight, MW 15000) and a solid content equivalent to 10 parts, The solution was dissolved, further adjusted to pH 4 with acetic acid, and refluxed at 50 ° C. for 3 hours. 1 part of 3- (2-aminoethylaminopropyl) trimethoxysilane is added to the solid content of this solution, and further diluted with 5 parts of carbon black (BP2000), 80 parts of methanol, 80 parts of acetone and 80 parts of toluene. The obtained liquid was stirred and dispersed with a homogenizer to obtain a coating solution. 5 parts of citric acid was dissolved in the solid content of the liquid, and applied to a ferrite core material (weight average particle size 35 μm) with a fluidized bed dryer to provide a nylon-silicone resin mixed coating layer. The obtained powder was heat-dried at 210 ° C. for 2 hours to obtain Carrier A having a coating layer thickness of 0.6 μm.
The carrier resistivity can be measured by the following method.
As shown in FIG. 1, a carrier (13) is filled into a cell (11) made of a fluororesin container containing a pair of parallel plate electrodes (12a) and (12b) having a distance between electrodes of 2 mm and a surface area of 2 × 4 cm. Then, a DC voltage of 100 V is applied between the two electrodes, the DC resistance is measured with a high resistance meter 4329A (manufactured by Yokogawa Hewlett-Packard Co., Ltd.), and the electrical resistivity LogR · Ωcm is calculated. The applied voltage measured the resistivity in 100V and 500V.
LogR of the electrical resistivity of this carrier was 14.5 Ωcm (50 V / mm) and 13.2 Ωcm (250 V / mm).
The carrier yield was determined by putting the prepared carrier into a mesh sieve having a mesh size of 63 μm, sieving it through a vibrating sieving machine, and measuring the ratio of those passing through the mesh.
The yield of this carrier was 86%.
[0032]
(Production Example 2)
Carrier B was obtained in the same manner as in Production Example 1 except that 3-aminopropyltriethoxysilane was used. LogR of the electrical resistivity of this carrier was 14.6 Ωcm (50 V / mm) and 13.6 Ωcm (250 V / mm). The yield of this carrier was 84%.
[0033]
(Production Example 3)
Carrier C was obtained in the same manner as in Production Example 1 except that dibutylaminopropyltrimethoxysilane was used. LogR of the electrical resistivity of this carrier was 14.1 Ωcm (50 V / mm) and 13.8 Ωcm (250 V / mm). The yield of this carrier was 77%.
[0034]
(Production Example 4)
A carrier D having a coating layer thickness of 0.6 μm was obtained in the same manner as in Production Example 1 except that the silicone resin used was a methylphenyl silicone resin having a SiOH content of 6 wt% and a molecular weight of MW 5000. LogR of the electrical resistivity of this carrier was 14.2 Ωcm (50 V / mm) and 13.1 Ωcm (250 V / mm). The yield of this carrier was 85%.
[0035]
(Production Example 5)
Carrier E was obtained in the same manner as in Production Example 4 except that the solid content of methoxymethylated polyamide was 7 parts and the solid content of silanol type methylphenyl silicone resin was 13 parts. LogR of the electrical resistivity of this carrier was 15.2 Ωcm (50 V / mm) and 14.6 Ωcm (250 V / mm). The carrier yield was 86%.
[0036]
(Production Example 6)
Carrier F was obtained in the same manner as in Production Example 4 except that the solid content of methoxymethylated polyamide was 13 parts and the solid content of silanol type methylphenyl silicone resin was 7 parts. LogR of the electrical resistivity of this carrier was 14.0 Ωcm (50 V / mm) and 13.0 Ωcm (250 V / mm). The yield of this carrier was 84%.
[0037]
(Production Example 7)
In Production Example 4, the equivalent of 2 parts of a solid content of a mixed solution of hexabutoxymethylated melamine, toluene and butanol was added, and a coating layer was formed in the same manner to obtain carrier particles G. LogR of the electrical resistivity of this carrier was 14.6 Ωcm (50 V / mm) and 13.3 Ωcm (250 V / mm). The yield of this carrier was 84%.
[0038]
(Production Example 8)
In Production Example 4, tetrabutoxymethylated benzoguanamine in a toluene / butanol mixed solution equivalent to 2 parts of solid content was added, and a coating layer was formed in the same manner to obtain carrier particles H. LogR of the electrical resistivity of this carrier was 15.2 Ωcm (50 V / mm) and 13.9 Ωcm (250 V / mm). The yield of this carrier was 88%.
[0039]
(Production Example 9)
In Production Example 6, Carrier I was obtained in the same manner except that adipic acid was used instead of citric acid. LogR of the electrical resistivity of this carrier was 14.5 Ωcm (50 V / mm) and 13.9 Ωcm (250 V / mm). The yield of this carrier was 84%.
[0040]
(Production Example 10)
In Production Example 7, 2 parts of hydrophobic silica R972 are added to the coating liquid with respect to the resin solid content, and the coating layer is formed using the coating liquid obtained by dispersing for 20 minutes with a homogenizer. Obtained Career J. LogR of the electrical resistivity of this carrier was 14.6 Ωcm (50 V / mm) and 14.3 Ωcm (250 V / mm). The yield of this carrier was 87%.
[0041]
(Production Example 11)
In Production Example 8, a coating layer was formed using a coating liquid obtained by adding 1 part of alumina fine particles having a particle size of 0.3 microns to the coating liquid, and then dispersing the same in a homogenizer. The carrier K was obtained in the same manner except that. LogR of the electrical resistivity of this carrier was 15.4 Ωcm (50 V / mm) and 13.6 Ωcm (250 V / mm). The yield of this carrier was 88%.
[0042]
(Production Example 12)
Carrier L was obtained in the same manner as in Production Example 1 except that 3- (2-aminoethylaminopropyl) trimethoxysilane was not used. LogR of the electrical resistivity of this carrier was 14.0 Ωcm (50 V / mm) and 13.5 Ωcm (250 V / mm). Further, the yield of this carrier was 56%.
[0043]
(Production Example 13)
Carrier M was obtained in the same manner as in Production Example 1 except that no silicone resin was used. LogR of the electrical resistivity of this carrier was 13.6 Ωcm (50 V / mm) and 12.4 Ωcm (250 V / mm). The yield of this carrier was 62%.
[0044]
(Production Example 14)
In Production Example 1, carrier particles were obtained without additional heating at 200 ° C. LogR of the electrical resistivity of this carrier N was 9.8 Ωcm (50 V / mm) and 8.5 Ωcm (250 V / mm). The yield of this carrier was 87%.
[0045]
(Production Example 15)
10 parts of methoxymethylated polyamide (manufactured by Nagase Chemtech Co., Ltd., EF30T) and 2 parts of a solid of a resol type phenolic resin (Sumitomo Bakelite, PR51283) are dissolved in 80 parts of methanol, adjusted to pH 4 with acetic acid, and 50 ° C. At reflux for 3 hours. 1 part of 3- (2-aminoethylaminopropyl) trimethoxysilane is added to the solid content of this solution, and 5 parts of carbon black (BP2000) and hydrophobic silica fine particles (R9725 part, Nippon Aerosil Co., Ltd.) are added. Further, a liquid diluted with 80 parts of methanol and 80 parts of acetone was stirred and dispersed with a homogenizer to obtain a coating solution. Thereafter, carrier O was obtained in the same manner as in Production Example 1. LogR of the electrical resistivity of this carrier was 13.7 Ωcm (50 V / mm) and 12.9 Ωcm (250 V / mm). The yield of this carrier was 82%.
[0046]
[Example 1]
93 parts of carrier A created in Production Example 1 and 7 parts of black toner for IPSIO Color 8000 are mixed and used as a developer. This is loaded into IPSIO Color 8000, and the image area ratio is 12%. A continuous print test was performed.
A small amount of developer was extracted at the start of the test and at the end of continuous printing, and the charge amount of the carrier in the developer was measured. Further, the background stain of the image at the end of printing 100,000 sheets and the charge amount of the developer were similarly evaluated.
The charge amount of the developer was determined based on a known blow-off method by collecting a small amount of developer from the sleeve of the developing device.
The thickness of the carrier was measured by crushing the carrier and observing with a scanning electron microscope.
The evaluation of the background dirt was a four-step evaluation by visual evaluation.
The coating layer uniformity was visually evaluated from an SEM observation image and evaluated in four stages.
The spent amount is obtained by dissolving 1 g of the carrier separated from the developer in 10 g of a 1: 1 mixed solution of MEK and toluene, measuring the absorbance of the supernatant with a spectrophotometer at 320 nm to 700 nm, and evaluating the average absorbance. did.
The evaluation results are shown in Table 2. The symbols described in the table are ◎: very good, ○: good, Δ: slightly bad, x: bad (x is an unacceptable level).
[0047]
[Examples 2 to 11, Comparative Examples 1 to 4]
In Example 1, each of the carriers B to O was used in place of the carrier A (see Table 1), and image evaluation was performed using the same developer. The results are also shown in Table 2.
[0048]
[Table 2-1]

[0049]
[Table 2-2]

[0050]
【The invention's effect】
As described above, as is clear from the detailed and specific description, according to the present invention, the chargeability of the coating layer is improved by the carrier provided with the coating layer using the alkoxyalkylated polyamide of the coating layer and the resin having reactivity with the polyamide. A carrier having excellent wear resistance is provided. Further, a resin and a silicone resin having a silanol group, adding an aminosilane coupling agent, by the action of catalyst in the heating step after coating, the durability of the charging, it is possible to reduce the variation due to the use environment Thus, it is possible to provide a carrier that is excellent in reliability and capable of improving productivity.
[Brief description of the drawings]
FIG. 1 is an apparatus for measuring the resistivity of a carrier used in a production example of the present invention.
[Explanation of symbols]
11 Cell 12a Electrode 12b Electrode 13 Carrier

Claims (13)

Having a coating layer on the core material surface with a magnetic, the coating layer and (i) N- alkoxyalkyl polyamides, and the N- alkoxyalkylated polyamide resin containing a silicone resin having at least silanol group (ii) reaction A carrier for developing an electrostatic latent image, comprising a condensate obtained from a mixture of one or more possible resins and (iii) an aminosilane coupling agent.   The carrier for developing an electrostatic latent image according to claim 1, wherein the amino equivalent of the aminosilane coupling agent is 170 to 230. An electrostatic latent image developing carrier according to claim 1 or 2 boiling in the coating layer is characterized by containing 100 ° C. or more solid organic acids. The carrier for developing an electrostatic latent image according to any one of claims 1 to 3 , wherein the coating layer has methylol melamine. An electrostatic latent image developing carrier according to any one of claims 1 to 4, characterized in that it has a methylol benzoguanamine in the coating layer. Applying LogR field 50V / electrical resistivity in mm is not less 14 or more, the electrostatic latent according to any one of claims 1 to 5, characterized in that LogR electrical resistivity at 250V / mm is 16 or less Image development carrier. An electrostatic latent image developing carrier according to any one of claims 1 to 6, characterized in that it contains a low-resistance material of the covering layer in resistivity 10 ^-3 ~10 ⁸ Ω · cm. The carrier for developing an electrostatic latent image according to claim 7 , wherein the low-resistance substance is conductive carbon. An electrostatic latent image developing carrier according to any one of claims 1 to 8, characterized in that it has a hard fine particles in the coating layer. 10. The electrostatic latent image development according to claim 9 , wherein the hard fine particles in the coating layer are metal oxide particles, and the metal oxide particles are any oxide of Si, Ti, and Al. For carrier. 11. The electrostatic latent image developing carrier according to claim 10 , wherein the content of the metal oxide particles in the coating layer is in the range of 5% to 70% of the weight of the coating layer. Electrostatic latent image developer comprising the electrostatic latent image carrier and an electrostatic latent image developing toner according to any one of claims 1 to 11. A photosensitive member, a charging brush for charging the surface of the photosensitive member, and a developing unit that develops an electrostatic latent image formed on the surface of the photosensitive member using the electrostatic latent image developer according to claim 12. And a blade for wiping off the developer remaining on the surface of the photoreceptor.

Images