JP3611334B2 - Electrostatic latent image developing carrier and electrostatic latent image two-component developer - Google Patents

Description

【００２２】
Ｒ_１〜Ｒ_４：水素原子または炭素数１〜１０の低級アルキル基、アリール基
ｎ ：正の整数
ｍ ：正の整数
Ｘ ：−ＣＯ，−ＳＯ_２
またさらに、トナーのバインダー樹脂をポリエステル樹脂とすることによる、耐塩ビマット融着性やカラートナーの色材の本来の色を損なうことのない、帯電の環境安定性の良好な電子写真用現像剤を得ることができる。
【００２３】
本発明においてシリコーン樹脂で被覆するキャリア核体粒子としては、従来より公知のものでよく、例えば鉄、コバルト、ニッケル等の強磁性金属；マグネタイト、ヘマタイト、フェライトなどの合金や化合物；ガラスビーズ等が挙げられる。これら核体粒子の平均粒径は通常１０〜１０００μｍ、好ましくは３０〜５００μｍである。なお、シリコーン樹脂の使用量としては、通常キャリア核体粒子に対して１〜１０重量％である。
【００２４】
本発明で用いられるシリコーン樹脂としては従来より知られるいずれのシリコーン樹脂であってもよく、例えば市販品として入手できる信越シリコーン社製のＫＲ２６１、ＫＲ２７１、ＫＲ２７２、ＫＲ２７５、ＫＲ２８０、ＫＲ２８２、ＫＲ２８５、ＫＲ２５１、ＫＲ１５５、ＫＲ２２０、ＫＲ２０１、ＫＲ２０４、ＫＲ２０５、ＫＲ２０６、ＳＡ−４、ＥＳ１００１、ＥＳ１００１Ｎ、ＥＳ１００２Ｔ、ＫＲ３０９３や東レシリコーン社製のＳＲ２１００、ＳＲ２１０１、ＳＲ２１０７、ＳＲ２１１０、ＳＲ２１０８、ＳＲ２１０９、ＳＲ２１１５、ＳＲ２４００、ＳＲ２４１０、ＳＲ２４１１、ＳＨ８０５、ＳＨ８０６Ａ、ＳＨ８４０等が用いられる。シリコーン樹脂層の形成法としては、従来と同様、キャリア核体粒子の表面に噴霧法、浸漬法等の手段でシリコーン樹脂を塗布すればよい。被覆層組成物はシリコーン樹脂溶液中に導電性微粉末とシランカップリング剤を添加して適宜のミキサーで分散して調製される。
【００２５】
被覆層中に分散される導電性微粉末は、０．０１〜５．０μｍ程度の粒径のものが好ましく、シリコーン樹脂１００重量部に対して０．０１〜３０重量部添加されることが好ましく、さらには０．１〜２０重量部が好ましい。導電性微粉末としては有機物質としては、従来より公知のカーボンブラックでよく、コンタクトブラック、ファーネスブラック、サーマルブラックが挙げられ、無機物質としては、ホウ化物、炭化物、窒化物、酸化物等が挙げられる。好ましくは微量で導電性効果を示すカーボンブラックがよい。
【００２６】
シランカップリング剤としては
Ｘ−Ｓｉ−Ｒｎ
（ｎは１〜３の整数）
なる式で表わされる化合物であり、Ｘは有機質と反応する官能基で、Ｒはアルコキシ基である。特に負極性を有する現像剤を得る場合には、アミノ基を有するアミノシランカップリング剤が望ましい。また特に正極性を有する現像剤を得る場合には、エポキシ基を有するエポキシシランカップリング剤が望ましい。
【００２７】
本発明において使用されるシランカップリング剤の具体的な例としては、次のような構造の化合物が使用できる。
【００２８】
（１） Ｈ_２ＮＣＨ_２ＣＨ_２ＣＨ_２Ｓｉ（ＯＣＨ_３）_３
（２） Ｈ_２ＮＣＨ_２ＣＨ_２ＣＨ_２Ｓｉ（ＯＣ_２Ｈ_５）_３
【００２９】
【化３】

【００３０】
（５） Ｈ_２ＮＣＯＮＨＣＨ_２ＣＨ_２ＣＨ_２Ｓｉ（ＯＣ_２Ｈ_５）_３
（６） Ｈ_２ＮＣＨ_２ＣＨ_２ＮＨＣＨ_２ＣＨ_２ＣＨ_２Ｓｉ（ＯＣＨ_３）_３
（７） Ｈ_２ＮＣＨ_２ＣＨ_２ＮＨＣＨ_２ＣＨ_２ＮＨＣＨ_２ＣＨ_２ＣＨ_２・Ｓｉ（ＯＣＨ_３）_３
（８） Ｈ_５Ｃ_２ＯＣＯＣＨ_２ＣＨ_２ＮＨＣＨ_２ＣＨ_２ＣＨ_２Ｓｉ（ＯＣＨ_３）_３
（９） Ｈ_５Ｃ_２ＯＣＯＣＨ_２ＣＨ_２ＮＨＣＨ_２ＣＨ_２ＮＨＣＨ_２ＣＨ_２ＣＨ_２・Ｓｉ（ＯＣＨ_３）_３
（１０） Ｈ_５Ｃ_２ＯＣＯＣＨ_２ＣＨ_２ＮＨＣＨ_２ＣＨ_２ＮＨＣＨ_２ＣＨ_２ＮＨＣＨ_２・ＣＨ_２ＮＨＣＨ_２ＣＨ_２ＣＨ_２Ｓｉ（ＯＣＨ_３）_３
（１１） Ｈ_３ＣＯＣＯＣＨ_２ＣＨ_２ＮＨＣＨ_２ＣＨ_２ＮＨＣＨ_２ＣＨ_２ＣＨ_２・Ｓｉ（ＯＣＨ_３）_３
【００３１】
【化４】

【００３２】
（１６） ＣＨ_２＝ＣＨＳｉ（ＯＣ_２Ｈ_５）_３
（１７） ＣＨ_２＝ＣＨＳｉ（ＯＣ_２Ｈ_４ＯＣＨ_３）_３
【００３３】
【化５】

【００３４】
【化６】

【００３５】
本発明において使用される有機スズ化合物の具体的な例としては次のような構造の化合物が使用できる。
【００３６】
（Ｉ） Ｒ_２Ｓ_ｎ（ＯＣＯＲ’）_２ （Ｒ及びＲ’はＣ_１〜Ｃ_１０のアルキル基）
（ＩＩ） ［Ｈ_３Ｃ（ＣＨ_２）_３］_２Ｓ_ｎ［ＯＯＣ（ＣＨ_２）_ｎＣＨ_３］_２
【００３７】
【化７】

【００３８】
【化８】

【００３９】
（Ｖ） ［ＣＨ_３（ＣＨ_２）_３］_２Ｓｎ（ＯＣＨ_３）_２
【００４０】
【化９】

【００４１】
（ＶＩＩＩ） Ｓ_ｎ（ＯＣＯＲ）_４ （ＲはＣ_１〜Ｃ_１０のアルキル基）
また、本発明において使用される極性制御剤の具体的な例としては、次のような構造の化合物が使用できる。
【００４２】
【化１０】

【００４３】
【化１１】

【００４４】
本発明において荷電制御剤として使用される前記化合物の使用量は、バインダー樹脂の種類、必要に応じて使用される添加剤の有無、分散方法を含めたトナー製造方法によって決定されるもので、一義的に限定されるものではないが、好ましくはバインダー樹脂１００重量部に対して、０．１〜２０重量部の範囲で用いられる。０．１重量部未満では、トナーの負帯電が不足し実用的でない。また２０重量部を越える場合にはトナーの帯電性が大きすぎ、キャリアとの静電的吸引力の増大のため、現像剤の流動性低下や、画像濃度の低下を招く。
【００４５】
本発明に使用されるバインダー樹脂としては、ポリスチレン、ポリ−ｐ−クロロスチレン、ポリビニルトルエンなどのスチレン及びその置換体の単重合体；スチレン−ｐ−クロロスチレン共重合体、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−ビニルナフタリン共重合体、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−アクリル酸オクチル共重合体、スチレン−メタクリル酸メチル共重合体、スチレン−メタクリル酸エチル共重合体、スチレン−メタクリル酸ブチル共重合体、スチレン−α−クロルメタ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−ビニルエ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−イソプレン共重合体、スチレン−アクリロニトリル−インデン共重合体、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など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、ポリアミド、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、脂肪族又は脂環族炭化水素樹脂、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挙げられ、単独あるいは混合して使用できる。
【００４６】
又特に圧力定着用に好適な結着樹脂として例を挙げると下記のものが単独あるいは混合して使用できる。
【００４７】
ポリオレフィン（低分子量ポリエチレン、低分子量ポリプロピレン、酸化ポリエチレンポリ４弗化エチレンなど）、エポキシ樹脂、ポリエステル樹脂、スチレン−ブタジエン共重合体（モノマー比５〜３０：９５〜７０）、オレフィン共重合体（エチレン−アクリル酸共重合体、エチレン−アクリル酸エステル共重合体、エチレン−メタクリル酸共重合体、エチレン−メタクリル酸エステル共重合体、エチレン−塩化ビニル共重合体、エチレン−酢酸ビニル共重合体、アイオノマー樹脂）、ポリビニルピロリドン、メチルビニルエーテル−無水マレイン酸共重合体、マレイン酸変性フェノール樹脂、フェノール変性テルペン樹脂等がある。また特に本発明で使用されるポリエステル樹脂としては、アルコールとカルボン酸との縮重合によって得られ、例えばアルコールとしては、ポリエチレングリコール、ジエチレングリコール、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二価のアルコール単位体、その他の二価のアルコール単位体、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、蔗糖、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三価以上の多価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、オレイン酸などのモノカルボン酸、マレイン酸、フマール酸、メサコン酸、シトラコン酸、イタコン酸、グルタコン酸、フタル酸、イソフタル酸、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二価の有機酸単量体、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の二量体、その他の二価の有機酸単量体、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、１，２，４−シクロヘキサントリカルボン酸、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−ジカルボキシル−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）メタル、１，２，７，８−オクタンテトラカルボン酸エンボール三量体酸、これらの酸の無水物等の三価以上の多価カルボン酸単量体を挙げることができる。
【００４８】
さらにまた、本発明で使用される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などであり、例えば、エポミックＲ３６２、Ｒ３６４、Ｒ３６５、Ｒ３６６、Ｒ３６７、Ｒ３６９（以上三井石油化学工業（株）製）、エポトートＹＤ−０１１、ＹＤ−０１２、ＹＤ−０１４、ＹＤ−９０４、ＹＤ−０１７（以上東都化成（株）製）、エピコート１００２、１００４、１００７（以上シェル化学社製）等市販のものがある。
【００４９】
本発明に使用される着色剤としては、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、フタロシアニングリーン、ハンザイエローＧ、ローダミン６Ｇレーキ、オルコオイルブルー、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、従来公知のいかなる染顔料をも単独あるいは混合して使用し得る。
【００５０】
更に本発明のトナーは、二成分系現像剤として用いる場合にはキャリア粉と混合して用いられる。
【００５１】
本発明のトナーは更に磁性材料を含有させ、磁性トナーとしても使用し得る。本発明の磁性トナー中に含まれる磁性材料としては、マグネタイト、ヘマタイト、フェライト等の酸化鉄、鉄、コバルト、ニッケルのような金属あるいはこれらの金属とアルミニウム、コバルト、銅、鉛、マグネシウム、スズ、亜鉛、アンチモン、ベリリウム、ビスマス、カドミウム、カルシウム、マンガン、セレン、チタン、タングステン、バナジウムのような金属の合金およびその混合物などが挙げられる。
【００５２】
これらの強磁性体は平均粒径が０．１〜２μｍ程度のものが望ましく、トナー中に含有させる量としては樹脂成分１００重量部に対し約２０〜２００重量部、特に好ましくは樹脂成分１００重量部に対し４０〜１５０重量部である。
【００５３】
又本発明のトナーは、必要に応じて添加物を混合してもよい。添加物としては、例えばテフロン、ステアリン酸亜鉛のごとき滑剤あるいは酸化セリウム、炭化ケイ素等の研磨剤、あるいは例えばコロイダルシリカ、酸化アルミニウムなどの流動性付与剤、ケーキング防止剤、あるいは例えばカーボンブラック、酸化スズ等の導電性付与剤、あるいは低分子量ポリオレフィンなどの定着助剤等がある。以下、本発明を下記の実施例によってさらに具体的に説明するが、本発明はこれに限定されるものではない。なお、部数はすべて重量部である。
【００５４】
次にいくつかのシリコーン樹脂を被覆層に有するキャリアの製造例を示す。これらは公知の手段により行うことができる。
【００５５】
製造例１
被覆層形成液の組成
シリコン樹脂溶液（東レシリコーン社製ＳＲ２４１０） １００部
酸化亜鉛 １０部
例示化合物Ｉ ０．４部
トルエン １００部
上記処方をホモミキサーで３０分間分散して被覆層形成液を調製した。この被覆層形成液を平均粒径１００μｍの球状フェライト１０００部の表面に流動床型塗布装置を用いて被覆層を形成したキャリアＡを得た。この時のＳｉ−Ｃ／Ｓｉ−Ｏ比をＸＰＳで測定したところ０．２であった。
【００５６】
製造例２〜９
下記第１表に示す各成分とトルエン１００部を混合し、ホモミキサーで３０分間分散して被覆層形成液を調製した。
【００５７】
【表１】

【００５８】
【表２】

【００５９】
この被覆層形成液を平均粒径１００μｍの球状フェライト１０００部の表面に流動床型塗布装置を用いて被覆層を形成したキャリアＢ、Ｃ、Ｄ、Ｅ、Ｆ、Ｇ、Ｈ、Ｉを得た。
【００６０】
【実施例】
実施例１
スチレン−ｎ−ブチルメタクリレート １００部
ポリプロピレン ５部
カーボンブラック ５部
含金属モノアゾ染料（オリエント化学社製ボントロンＳ−３４） ３部
上記組成の混合物をヘンシェルミキサー中で十分撹拌混合した後、ロールミルで１３０〜１４０℃の温度で約３０分間加熱溶融し、室温まで冷却後、得られた混練物を粉砕分級し、５〜２０μｍの粒径の黒色トナーを得た。
【００６１】
このトナー２．５部に対し、シリコーンキャリアＡ９７．５部とをボールミルで混合し、現像剤を得た。
【００６２】
次に上記現像剤を当社製ＦＴ７５７０にセットし、現像を行ったところ、鮮明な高画質が得られ、その画像は１０万枚画像出し後も変わらなかった。
【００６３】
また、トナーの帯電量をブローオフ法で測定したところ、初期の帯電量は−２２．１μｃ／ｇであり、１０万枚ランニング後におけるトナーの帯電量は−２０．２μｃ／ｇと初期値とほとんど差がなかった。
【００６４】
比較例１
実施例１のシリコーンキャリアＡをＳｉ−Ｃ／Ｓｉ−Ｏ値０．０５のキャリアＢに変えること以外は実施例１と同様に現像剤を得、画像テストを行った。初期画像から、カブリのある不鮮明な画像が得られた。また、実施例１と同様に帯電量を測定したところ、初期の帯電量は−８．２μｃ／ｇと低い値であり、３万枚後のキャリア被覆層の厚さは初期から０．４μ削れていた。
【００６５】
比較例２
実施例１のシリコーンキャリアＡをＳｉ−Ｃ／Ｓｉ−Ｏ値１．２のキャリアＣに変えること以外は実施例１と同様に現像剤を得、画像テストを行った。初期画像は、濃度の薄い不鮮明な画像が得られたが、１万枚頃からカブリのある不鮮明な画像になった。また、実施例１と同様に帯電量を測定したところ、初期の帯電量は−３１．１μｃ／ｇであった。この１万枚ランニング後のキャリアの表面を電顕観察したところ、被覆層が割れて剥がれていた。
【００６６】
比較例３
実施例１のシリコーンキャリアＡから有機スズを除いたキャリアＤを用いたこと以外は実施例１と同様に現像剤を得、画像テストを行った。初期画像は、カブリのない鮮明な画像が得られたが、１万枚頃から、カブリのある不鮮明な画像になった。また、実施例１と同様に帯電量を測定したところ、初期の帯電量は−１３．１μｃ／ｇと低く、３万枚後には−６．３μｃ／ｇとさらに低下していた。実施例２
実施例１のシリコーンキャリアＡを有機スズ未添加でクロロシランカップリング剤含有のシリコーンキャリアＥに替えること以外は実施例１と同様に現像剤を得、画像テストを行ったところ鮮明な高画質が得られ、その画像は１５万枚画像出し後も変わらなかった。
【００６７】
また、トナーの帯電量をブローオフ法で測定したところ、初期の帯電量は−２２．１μｃ／ｇであり、１５万枚ランニング後におけるトナーの帯電量は−２０．８μｃ／ｇと初期値とほとんど差がなかった。
【００６８】
実施例３
実施例１のシリコーンキャリアＡを有機スズ未添加で導電性微粉末がカーボンブラックでアミノシランカップリング剤含有のシリコーンキャリアＦに変えること以外は実施例１と同様に現像剤を得、画像テストを行ったところ鮮明な高画質が得られ、その画像は２０万枚画像出し後も変わらなかった。
【００６９】
また、トナーの帯電量をブローオフ法で測定したところ、初期の帯電量は−２４．３μｃ／ｇであり、２０万枚ランニング後におけるトナーの帯電量は−２３．８μｃ／ｇと初期値とほとんど差がなかった。
【００７０】
実施例４
ポリエステル樹脂 ９０部
スチレン−ン−ｎ−ブチルメタクリレート １０部
例示含フッ素化合物ａ ２．５部
含金属モノアゾ染料（オリエント化学社製ボントロンＳ−３４） ３部
カーボンブラック ５部
上記組成の混合物を実施例１と同様に、ヘンシェルミキサー中で十分撹拌混合した後、ロールミルで１３０〜１４０℃の温度で約３０分間加熱溶融し、室温まで冷却後、得られた混練物を粉砕分級し、５〜２０μｍの粒径のトナーを得た。このトナー１００部に対し、疎水性コロイダルシリカ０．４部をスピードニーダで十分撹拌混合してトナーとした。
【００７１】
このトナー２．５部に対し、シリコーンキャリアＦ９７．５部とをボールミルで混合し、現像剤を得た。また実施例１と同様な画像出しテストを行ったところ、鮮明な高画質が得られ、その画像は２０万枚画像出し後も変わらなかった。
【００７２】
また、トナーの帯電量をブローオフ法で測定したところ、初期の帯電量は−２４．４μｃ／ｇであり、２０万枚ランニング後におけるトナーの帯電量は−２３．９μｃ／ｇと初期値とほとんど差がなかった。又３５℃９０％ＲＨという高湿環境下では−２４．２μｃ／ｇ、及び１０℃１５％ＲＨという低湿環境下では−２４．３μｃ／ｇ、常温とあまり変わらない帯電量を示し、同等の画像が得られた。
【００７３】
また、実施例１と同様に塩ビマット保存性を試験したところ、マットへのトナーの融着はみられず、良好な塩ビマット保存性を示した。
【００７５】
実施例５
実施例４でキャリアのアミノシランカップリング剤を除いたシリコーンキャリアＧを用いた以外は実施例４と同様に現像剤を得、画像テストを行った。初期画像及び８万枚後の画像は、カブリのない鮮明な画像が得られた。また、実施例１と同様に帯電量を測定したところ、初期の帯電量は−１６．１μｃ／ｇであったが、８万枚後には−１５．５μｃ／ｇと安定していた。
【００７６】
実施例６
スチレン−ｎ−ブチルメタクリレート １００部
フタロシアニンブルー ５部
第４級アンモニウム塩（オリエント化学社製ボントロンＰ−５１） ２部
上記組成の混合物を１２０℃の熱ロールで溶融混練した後、冷却固化せしめ、これをジェットミルで粉砕し、５〜２０μｍの粒径のトナーを得た。このトナー２．５部に対してシリコーンキャリアＨ、９７．５部とをボールミルで混合し、現像剤を得た。この現像剤を当社製の複写機ＦＴ７５７０にセットし、画像テストを行ったところ、鮮明な高画質が得られ、その画像は２０万枚画像出し後も変わらなかった。
【００７７】
また、トナーの帯電量をブローオフ法で測定したところ、初期の帯電量は＋２５．４μｃ／ｇであり、１０万枚ランニング後におけるトナーの帯電量は＋２４．９μｃ／ｇと初期値とほとんど差がなかった。又２０万枚後のキャリア被覆膜の厚さは、初期から約０．１μ摩耗していた。
【００７８】
比較例４
実施例６でキャリアのエポキシシランカップリング剤を除いたキャリアＩを用いたこと以外は実施例６と同様に現像剤を得、画像テストを行った。初期画像は、カブリのない鮮明な画像が得られたが、１万枚頃から、カブリのある不鮮明な画像になった。また、実施例１と同様に帯電量を測定したところ、初期の帯電量は＋２０．１μｃ／ｇであったが、３万枚後には＋６．３μｃ／ｇと低下していた。また、１０万枚後のキャリア被覆膜の厚さは初期から約０．２μ摩耗していた。
【００７９】
【発明の効果】
以上述べたように、本発明のような特定の電子写真用現像用キャリア及び現像剤を使用することによって、連続複写後も初期画像と同等の品質を示す画像が得られ、安定した摩擦帯電性が得られ、鮮明なコピー画像が得られる。[0001]
[Industrial application fields]
The present invention relates to an electrophotographic carrier and developer used for electrophotography, electrostatic printing and the like.
[0002]
[Prior art]
Conventionally, so-called two-component dry developers composed of a mixture of carrier particles and toner particles are well known. In this two-component dry developer, minute toner particles are held on the surface of relatively large particles by the electric force generated by the friction of both particles. The attracting force in the electrostatic direction with respect to the toner particles by the electric field to be formed overcomes the binding force between the toner particles and the carrier particles, and the toner particles are attracted and adhered onto the electrostatic latent image to visualize the electrostatic latent image. Is. The developer is repeatedly used while replenishing the toner consumed by the development.
[0003]
In general, metal oxides such as magnetite and ferrite are widely used as carrier materials for two-component developers because their apparent density is small compared to iron powder carriers and the like, and they can be reduced in weight as developers. When the developer is stirred in the developing device, the stirring resistance is reduced. Furthermore, it has the characteristics that the residual magnetic flux density is low and the coercive force is small and the area of the hysteresis loop is small compared to the iron powder carrier, and the initial characteristics are always maintained for the magnetization reversal and the magnetization history. It has characteristics. Magnetite, ferrite, etc. are oxides and are chemically stable. Ozone and NO generated in the copier_XIt is difficult for chemical changes to occur.
[0004]
However, such oxide carriers such as ferrite and magnetite also generate mechanical collisions such as collisions between developer particles due to high-speed development and multiple sheet copying, collisions between developer particles and a developing machine, or heat generated by these actions. As a result, the toner film is formed on the carrier surface, so-called spent, and the charging characteristics of the carrier deteriorate with use time, causing toner scattering, ground fogging, and the like.
[0005]
In order to prevent such spenting, methods for coating the surface of the core particles with various resins have been proposed, but no satisfactory one has been obtained yet. For example, a carrier coated with a resin such as a styrene-methacrylate copolymer or a styrene polymer has excellent charging characteristics, but the surface has a relatively high critical surface tension. The lifetime as a developer was not so long. In addition, the carrier coated with the tetrafluoroethylene polymer is less likely to be spent on the toner, but the tetrafluoroethylene polymer is located on the most negative side in the triboelectric charging series, so that the toner is negatively charged. If you want to use it.
[0006]
On the other hand, a method of coating the carrier surface with a material having a low surface energy such as silicone has been devised, but the carrier having such a resin coating has the following two drawbacks. It was. The first drawback is that when the carrier is used as a developer due to the high electric resistance of the carrier, the image quality is inferior due to edge development or charge accumulation phenomenon. The second drawback is that the coating film of the carrier wears over time due to mechanical friction such as friction between developer particles due to high-speed development or multiple sheet copying, or friction between developer particles and the developing machine, The charging characteristics were deteriorated.
[0007]
The first drawback of the coated carrier can be improved by dispersing a conductive substance in the coating layer. That is, when a certain degree of conductivity is given to the carrier, the carrier acts as a developing electrode, and development is performed in a state where the developing electrode and the surface of the photoconductor to be developed are in very close contact with each other. Even a black area with a large area is faithfully reproduced exactly as it was written.
[0008]
Conventionally, carbon, tin oxide or the like has been used as such a conductive material. However, when such a conductive material is dispersed in the coating layer of the carrier, the following drawbacks occur.
[0009]
In general, the toner and the carrier are charged by contacting each other. In this case, if the electric resistance of the carrier is reduced, the charge generated in the toner passes through the carrier and the charge amount cannot be maintained. Further, there is a problem that the conductive material is detached from the coating layer due to use over time and the charge amount is changed. In order to solve this problem, Japanese Patent Application Laid-Open No. 62-182759 improves the carbon by treating it with aminosilane, amino-modified silicone oil or the like, but the problem is that the cost increases due to an increase in the number of treatment steps. It was.
[0010]
In addition, a styrene resin has been conventionally used as a binder resin for the toner, but this toner is excellent in stability of charge amount over time and in the environment, but it can be fused to a PVC mat, There were many problems such as inability to cope with low-temperature fixing. In recent years, polyester resins have been used as means for solving these problems. Since the polyester resin itself has a negative triboelectric chargeability, there is an advantage that the amount of the polarity control agent, which is expensive, can be reduced when obtaining a negatively chargeable toner. Also, good fixing can be achieved at a low temperature without causing an offset phenomenon. Furthermore, since the SP value of the polyester resin is different from the SP value of the plasticizer in the vinyl mat, fusion can be prevented. However, conventionally used as a negative charge control agent are metal complexes of monoazo dyes, nitrohumic acid and its salts, metal complexes of salicylic acid, naphthoic acid, dicarboxylic acid such as Co, Cr, Fe, and sulfonated copper. There are phthalocyanine pigments, nitro oligomers, styrene oligomers introduced with halogens, chlorinated paraffins, melamine resins, etc., but these dyes have a complex structure, are not constant in nature, and have poor stability. In addition, during thermal kneading, it is likely to be decomposed or altered due to decomposition, mechanical shock, friction, changes in temperature and humidity conditions, and the like, and a phenomenon in which charge controllability is likely to deteriorate is likely to occur. In many cases, the chargeability changes depending on the environment. Furthermore, when a conventional toner containing the charge control agent is used for a long time, filming may occur on the photoreceptor due to poor charging.
[0011]
Therefore, the combination of a toner using a polyester resin as a binder resin and a carrier coated with a silicone resin has a low charge amount, poor environmental stability, a decrease in charge amount over time, fogging, toner scattering, etc. There was a problem that it was difficult to use. This is presumably because the polyester resin has functional groups such as —COOH and —OH groups remaining due to its chemical structure, which inhibits maintaining stable chargeability.
[0012]
[Problems to be solved by the invention]
The object of the present invention is that there is no scumming or toner scattering, there is no deterioration in image quality due to edge phenomenon or charge accumulation phenomenon, and even during continuous use, the coating layer cracks, peels off, wears, and the conductive fine powder is detached. Therefore, it is an object of the present invention to provide a carrier for developing an electrostatic latent image that is stable in triboelectric charge and can provide an image with high fidelity equivalent to that of an initial image. Another object of the present invention is to provide a developer in which the frictional charge between the toner and the carrier is stable and the triboelectric charge amount distribution is sharp and uniform. Another object is to provide a developer capable of controlling the charge amount suitable for the developing system to be used. Furthermore, another object is to provide a developer capable of reproducing a stable image that is not affected by changes in temperature and humidity. In addition, there is no background stain or toner scattering, image quality is not deteriorated due to edge phenomenon or charge accumulation phenomenon, and carrier coating layer is not peeled off even during continuous use, and conductive fine powder is not detached. An object of the present invention is to provide a two-component developer that is stable in charge and can provide an image with high fidelity equivalent to the initial image.
[0013]
[Means for Solving the Problems]
As a result of intensive studies, the present inventors have determined that the ratio of Si—C bond to Si—O bond in the silicone resin coating layer is Si—C / Si—O in the electrophotographic carrier having the silicone resin coating layer. It has been found that the above-mentioned drawbacks can be eliminated by setting the value in a range of 0.15 to 0.35. When the ratio of Si-C bond to Si-O bond, Si-C / Si-O, is smaller than 0.15, the coating layer is soft and the film is scraped after a long period of use, and the triboelectric charge is caused by exposure of the carrier core material. It is easy to deteriorate. On the other hand, if it is larger than 0.35, the silicone coating layer is hard and brittle and easily cracks, resulting in poor durability. Therefore, it is necessary to keep the range of 0.15 to 0.35. Further, since the charge level changes depending on the value of Si—C / Si—O, it is also possible to use the value by changing the value as means for obtaining a desired charge amount. The value of this coupling ratio can be measured using XPS.
[0014]
In particular, by changing the amount of the organotin compound as a curing catalyst in the silicone resin layer of the carrier, the toner can be easily charged to a desired charge amount.
[0015]
The present invention also provides the carrier with the same advantages as the conventional silicone resin-coated carrier by coating the core particle surface with a silicone resin containing conductive fine powder and a silane coupling agent. By imparting conductivity, the phenomenon of charge accumulation on carriers, peeling of the coating layer, and detachment of the conductive fine powder are effectively suppressed.
[0016]
Further, in particular, the silicone resin coating layer of the carrier contains conductive fine powder and a silane coupling agent, and the conductive fine powder is carbon black. Thus, an electrophotographic two-component development carrier that does not deteriorate image quality due to the accumulation phenomenon and exhibits stable triboelectric chargeability even when used over time was obtained.
[0017]
In particular, when obtaining a developer having a desired negative polarity, the silane coupling agent is an amino silane coupling agent having an amino group, which is durable and stable in the use over time. An electrophotographic two-component developing carrier exhibiting triboelectric charge imparting properties was obtained.
[0018]
In particular, in the case of obtaining a developer having a desired positive polarity, the positive electrode is durable and stable even over time because the silane coupling agent is an epoxy silane coupling agent having an epoxy group. A two-component developing carrier for electrophotography that exhibits a high triboelectric chargeability was obtained.
[0019]
In the electrophotographic developer comprising a carrier and a toner, the toner contains at least a polyester resin as a binder resin and a fluorine-containing quaternary ammonium salt compound represented by the following general formula as a polarity control agent. An electron having a silicone resin coating layer containing fine powder and having a value of Si—C bond and Si—O bond ratio Si—C / Si—O in the silicone resin layer in the range of 0.15 to 0.35. Photographic developers have solved the above problems better.
[0020]
General formula (1)
[0021]
[Chemical 2]

[0022]
R₁~ R₄: A hydrogen atom or a lower alkyl group having 1 to 10 carbon atoms, an aryl group
n: positive integer
m: positive integer
X: -CO, -SO₂
Furthermore, by using a polyester resin as the binder resin of the toner, an electrophotographic developer having good charging environmental stability without impairing the PVC mat fusion resistance and the original color of the color toner coloring material. Can be obtained.
[0023]
The carrier core particles coated with the silicone resin in the present invention may be those conventionally known, for example, ferromagnetic metals such as iron, cobalt and nickel; alloys and compounds such as magnetite, hematite and ferrite; glass beads and the like. Can be mentioned. The average particle diameter of these core particles is usually 10 to 1000 μm, preferably 30 to 500 μm. In addition, the usage-amount of a silicone resin is 1 to 10 weight% normally with respect to a carrier core particle.
[0024]
The silicone resin used in the present invention may be any conventionally known silicone resin, such as KR261, KR271, KR272, KR275, KR280, KR282, KR285, KR251, manufactured by Shin-Etsu Silicone Co., Ltd., which are commercially available. KR155, KR220, KR201, KR204, KR205, KR206, SA-4, ES1001, ES1001N, ES1002T, KR3093, SR2100, SR2101, SR2107, SR2110, SR2108, SR2109, SR2115, SR2400, SR2410, SR2411, manufactured by Toray Silicone SH806A, SH840, etc. are used. As a method for forming the silicone resin layer, a silicone resin may be applied to the surface of the carrier core particles by means of a spraying method, a dipping method or the like, as in the past. The coating layer composition is prepared by adding conductive fine powder and a silane coupling agent to a silicone resin solution and dispersing with a suitable mixer.
[0025]
The conductive fine powder dispersed in the coating layer preferably has a particle size of about 0.01 to 5.0 μm, and is preferably added in an amount of 0.01 to 30 parts by weight with respect to 100 parts by weight of the silicone resin. Furthermore, 0.1-20 weight part is preferable. As the conductive fine powder, the organic substance may be a conventionally known carbon black, and examples thereof include contact black, furnace black, and thermal black, and the inorganic substance includes boride, carbide, nitride, oxide, and the like. It is done. Carbon black showing a conductive effect in a small amount is preferable.
[0026]
As a silane coupling agent
X-Si-Rn
(N is an integer of 1 to 3)
Wherein X is a functional group that reacts with an organic substance, and R is an alkoxy group. In particular, when a developer having negative polarity is obtained, an aminosilane coupling agent having an amino group is desirable. In particular, when obtaining a developer having positive polarity, an epoxy silane coupling agent having an epoxy group is desirable.
[0027]
As a specific example of the silane coupling agent used in the present invention, a compound having the following structure can be used.
[0028]
(1) H₂NCH₂CH₂CH₂Si (OCH₃)₃
(2) H₂NCH₂CH₂CH₂Si (OC₂H₅)₃
[0029]
[Chemical 3]

[0030]
(5) H₂NCONHCH₂CH₂CH₂Si (OC₂H₅)₃
(6) H₂NCH₂CH₂NHCH₂CH₂CH₂Si (OCH₃)₃
(7) H₂NCH₂CH₂NHCH₂CH₂NHCH₂CH₂CH₂・ Si (OCH₃)₃
(8) H₅C₂OCOCH₂CH₂NHCH₂CH₂CH₂Si (OCH₃)₃
(9) H₅C₂OCOCH₂CH₂NHCH₂CH₂NHCH₂CH₂CH₂・ Si (OCH₃)₃
(10) H₅C₂OCOCH₂CH₂NHCH₂CH₂NHCH₂CH₂NHCH₂・ CH₂NHCH₂CH₂CH₂Si (OCH₃)₃
(11) H₃COCOCH₂CH₂NHCH₂CH₂NHCH₂CH₂CH₂・ Si (OCH₃)₃
[0031]
[Formula 4]

[0032]
(16) CH₂= CHSi (OC₂H₅)₃
(17) CH₂= CHSi (OC₂H₄OCH₃)₃
[0033]
[Chemical formula 5]

[0034]
[Chemical 6]

[0035]
As a specific example of the organotin compound used in the present invention, a compound having the following structure can be used.
[0036]
(I) R₂S_n(OCOR ’)₂  (R and R 'are C₁~ C₁₀Alkyl group)
(II) [H₃C (CH₂)₃]₂S_n[OOC (CH₂)_nCH₃]₂
[0037]
[Chemical 7]

[0038]
[Chemical 8]

[0039]
(V) [CH₃(CH₂)₃]₂Sn (OCH₃)₂
[0040]
[Chemical 9]

[0041]
(VIII) S_n(OCOR)₄  (R is C₁~ C₁₀Alkyl group)
Further, as a specific example of the polarity control agent used in the present invention, a compound having the following structure can be used.
[0042]
[Chemical Formula 10]

[0043]
Embedded image

[0044]
The amount of the compound used as the charge control agent in the present invention is determined by the toner production method including the type of the binder resin, the presence or absence of additives used as necessary, and the dispersion method. Although not specifically limited, Preferably it is used in 0.1-20 weight part with respect to 100 weight part of binder resin. If the amount is less than 0.1 parts by weight, the toner is not practically negatively charged. On the other hand, when the amount exceeds 20 parts by weight, the chargeability of the toner is too high, and the electrostatic attraction force with the carrier increases, leading to a decrease in developer fluidity and a decrease in image density.
[0045]
The binder resin used in the present invention includes styrene such as polystyrene, poly-p-chlorostyrene, and polyvinyltoluene, and homopolymers of substituted products thereof; styrene-p-chlorostyrene copolymer, styrene-propylene copolymer. Styrene-vinyltoluene copolymer, styrene-vinylnaphthalene copolymer, styrene-methyl acrylate copolymer, styrene-ethyl acrylate copolymer, styrene-butyl acrylate copolymer, styrene-octyl acrylate copolymer Polymer, styrene-methyl methacrylate copolymer, styrene-ethyl methacrylate copolymer, styrene-butyl methacrylate copolymer, styrene-α-chloromethyl methacrylate copolymer, styrene-acrylonitrile copolymer, styrene -Vinyl methyl ether copolymer, steel -Vinyl ethyl ether copolymer, styrene-vinyl methyl ketone copolymer, styrene-butadiene copolymer, styrene-isoprene copolymer, styrene-acrylonitrile-indene copolymer, styrene-maleic acid copolymer, styrene -Styrene copolymers such as maleic acid ester copolymers; polymethyl methacrylate, polybutyl methacrylate, polyvinyl chloride, polyvinyl acetate, polyethylene, polypropylene, polyester, polyurethane, polyamide, epoxy resin, polyvinyl butyral, polyacrylic acid Resins, rosins, modified rosins, terpene resins, phenol resins, aliphatic or alicyclic hydrocarbon resins, aromatic petroleum resins, chlorinated paraffins, paraffin waxes and the like can be used, and these can be used alone or in combination.
[0046]
In addition, as examples of binder resins particularly suitable for pressure fixing, the following can be used alone or in combination.
[0047]
Polyolefin (low molecular weight polyethylene, low molecular weight polypropylene, polyethylene oxide polytetrafluoroethylene, etc.), epoxy resin, polyester resin, styrene-butadiene copolymer (monomer ratio 5-30: 95-70), olefin copolymer (ethylene -Acrylic acid copolymer, ethylene-acrylic acid ester copolymer, ethylene-methacrylic acid copolymer, ethylene-methacrylic acid ester copolymer, ethylene-vinyl chloride copolymer, ethylene-vinyl acetate copolymer, ionomer Resin), polyvinylpyrrolidone, methyl vinyl ether-maleic anhydride copolymer, maleic acid-modified phenol resin, phenol-modified terpene resin, and the like. In particular, the polyester resin used in the present invention is obtained by condensation polymerization of an alcohol and a carboxylic acid. Examples of the alcohol include polyethylene glycol, diethylene glycol, triethylene glycol, 1,2-propylene glycol, 1,3- Diols such as propylene glycol, 1,4-propylene glycol, neopentyl glycol, 1,4-butenediol, 1,4-bis (hydroxymethyl) cyclohexane, bisphenol A, hydrogenated bisphenol A, polyoxyethylenated bisphenol A , Etherified bisphenols such as polyoxypropylenated bisphenol A, divalent alcohol units obtained by substituting these with saturated or unsaturated hydrocarbon groups having 3 to 22 carbon atoms, and other divalent alcohol units Body, sorbitol, 1,2,3,6-hexanetetrol, 1,4-sarbitane, pentaerythritol, dipentaerythritol, tripentaerythritol, sucrose, 1,2,4-butanetriol, 1,2,5- Trivalent or higher polyvalent such as pentanetriol, glycerol, 2-methylpropanetriol, 2-methyl-1,2,4-butanetriol, trimethylolethane, trimethylolpropane, 1,3,5-trihydroxymethylbenzene Mention may be made of alcohol monomers. 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, itaconic acid, glutaconic acid, and phthalic acid. , Isophthalic acid, terephthalic acid, cyclohexanedicarboxylic acid, succinic acid, adipic acid, sebacic acid, malonic acid, divalent organic acid monomers substituted with saturated or unsaturated hydrocarbon groups having 3 to 22 carbon atoms , Anhydrides of these acids, dimers of lower alkyl esters and linolenic acid, other divalent organic acid monomers, 1,2,4-benzenetricarboxylic acid, 1,2,5-benzenetricarboxylic acid, 1,2,4-cyclohexanetricarboxylic acid, 2,5,7-naphthalenetricarboxylic acid, 1,2,4-naphthalene Recarboxylic acid, 1,2,4-butanetricarboxylic acid, 1,2,5-hexanetricarboxylic acid, 1,3-dicarboxyl-2-methyl-2-methylenecarboxypropane, tetra (methylenecarboxyl) metal, 1,2 , 7,8-octanetetracarboxylic acid embol trimer acid, trivalent or higher polyvalent carboxylic acid monomers such as anhydrides of these acids.
[0048]
Furthermore, the epoxy resin used in the present invention is a polycondensate of bisphenol A and epichlorohydrin, for example, Epomic R362, R364, R365, R366, R367, R369 (Mitsui Petrochemical Co., Ltd.) ), Epototo YD-011, YD-012, YD-014, YD-904, YD-017 (manufactured by Tohto Kasei Co., Ltd.), Epicoat 1002, 1004, 1007 (manufactured by Shell Chemical Co., Ltd.) There is.
[0049]
Colorants used in the present invention include carbon black, lamp black, iron black, ultramarine blue, nigrosine dye, aniline blue, phthalocyanine blue, phthalocyanine green, Hansa Yellow G, rhodamine 6G lake, olco oil blue, chrome yellow, quinacridone. Any conventionally known dyes such as benzidine yellow, rose bengal, triallylmethane dyes, monoazo dyes and disazo dyes can be used alone or in combination.
[0050]
Further, the toner of the present invention is used by mixing with carrier powder when used as a two-component developer.
[0051]
The toner of the present invention further contains a magnetic material and can be used as a magnetic toner. Examples of the magnetic material contained in the magnetic toner of the present invention include iron oxides such as magnetite, hematite, and ferrite, metals such as iron, cobalt, and nickel, and these metals and aluminum, cobalt, copper, lead, magnesium, tin, Examples include alloys of metals such as zinc, antimony, beryllium, bismuth, cadmium, calcium, manganese, selenium, titanium, tungsten, vanadium, and mixtures thereof.
[0052]
These ferromagnetic materials preferably have an average particle size of about 0.1 to 2 μm. The amount of the ferromagnetic material to be contained in the toner is about 20 to 200 parts by weight, particularly preferably 100 parts by weight of the resin component, with respect to 100 parts by weight of the resin component. 40 to 150 parts by weight per part.
[0053]
The toner of the present invention may be mixed with additives as necessary. Examples of additives include lubricants such as Teflon and zinc stearate, abrasives such as cerium oxide and silicon carbide, fluidity imparting agents such as colloidal silica and aluminum oxide, anti-caking agents, or carbon black and tin oxide, for example. And a fixing aid such as a low molecular weight polyolefin. Hereinafter, the present invention will be described more specifically with reference to the following examples, but the present invention is not limited thereto. All parts are parts by weight.
[0054]
Next, the manufacture example of the carrier which has some silicone resins in a coating layer is shown. These can be performed by known means.
[0055]
Production Example 1
Composition of coating layer forming solution
100 parts of silicone resin solution (SR2410 manufactured by Toray Silicone Co., Ltd.)
10 parts of zinc oxide
Illustrative Compound I 0.4 parts
100 parts of toluene
The above formulation was dispersed with a homomixer for 30 minutes to prepare a coating layer forming solution. Carrier A in which the coating layer was formed on the surface of 1000 parts of spherical ferrite having an average particle size of 100 μm by using a fluidized bed coating apparatus was obtained from this coating layer forming liquid. When the Si—C / Si—O ratio at this time was measured by XPS, it was 0.2.
[0056]
Production Examples 2-9
Each component shown in Table 1 below and 100 parts of toluene were mixed and dispersed with a homomixer for 30 minutes to prepare a coating layer forming solution.
[0057]
[Table 1]

[0058]
[Table 2]

[0059]
Carriers B, C, D, E, F, G, H, and I in which a coating layer was formed on the surface of 1000 parts of spherical ferrite having an average particle diameter of 100 μm by using a fluidized bed coating apparatus were obtained from this coating layer forming liquid. .
[0060]
【Example】
Example 1
100 parts of styrene-n-butyl methacrylate
5 parts of polypropylene
Carbon black 5 parts
Metal-containing monoazo dye (Orient Chemical Co., Ltd. Bontron S-34) 3 parts
The mixture having the above composition was sufficiently stirred and mixed in a Henschel mixer, then heated and melted at a temperature of 130 to 140 ° C. for about 30 minutes with a roll mill, cooled to room temperature, and then the obtained kneaded product was pulverized and classified, and 5 to 20 μm in size. A black toner having a particle size was obtained.
[0061]
A toner was obtained by mixing 2.5 parts of this toner with 97.5 parts of silicone carrier A using a ball mill.
[0062]
Next, when the developer was set in FT7570 manufactured by our company and developed, a clear high image quality was obtained, and the image did not change even after the 100,000 sheets were put out.
[0063]
Further, when the charge amount of the toner was measured by the blow-off method, the initial charge amount was −22.1 μc / g, and the charge amount of the toner after running 100,000 sheets was −20.2 μc / g, almost the initial value. There was no difference.
[0064]
Comparative Example 1
A developer was obtained in the same manner as in Example 1 except that the silicone carrier A in Example 1 was changed to a carrier B having a Si—C / Si—O value of 0.05, and an image test was performed. From the initial image, a blurred and blurred image was obtained. Further, when the charge amount was measured in the same manner as in Example 1, the initial charge amount was a low value of -8.2 μc / g, and the thickness of the carrier coating layer after 30,000 sheets was scraped by 0.4 μm from the initial value. It was.
[0065]
Comparative Example 2
A developer was obtained in the same manner as in Example 1 except that the silicone carrier A in Example 1 was changed to the carrier C having a Si—C / Si—O value of 1.2, and an image test was performed. As the initial image, an unclear image having a low density was obtained, but from around 10,000 sheets, the image was blurred. Further, when the charge amount was measured in the same manner as in Example 1, the initial charge amount was -31.1 μc / g. When the surface of the carrier after running 10,000 sheets was observed with an electron microscope, the coating layer was cracked and peeled off.
[0066]
Comparative Example 3
A developer was obtained in the same manner as in Example 1 except that the carrier D obtained by removing organotin from the silicone carrier A in Example 1 was used, and an image test was performed. As the initial image, a clear image without fogging was obtained, but from around 10,000 sheets, it became a blurry image with fogging. Further, when the charge amount was measured in the same manner as in Example 1, the initial charge amount was as low as −13.1 μc / g, and after 30,000 sheets, it was further decreased to −6.3 μc / g. Example 2
A developer was obtained in the same manner as in Example 1 except that the silicone carrier A of Example 1 was replaced with a silicone carrier E containing no chlorosilane coupling agent without addition of organotin, and a clear image quality was obtained when an image test was performed. The image did not change after 150,000 images were put out.
[0067]
Further, when the charge amount of the toner was measured by the blow-off method, the initial charge amount was −22.1 μc / g, and the toner charge amount after running 150,000 sheets was −20.8 μc / g, almost the initial value. There was no difference.
[0068]
Example 3
A developer was obtained in the same manner as in Example 1 except that the silicone carrier A of Example 1 was changed to a silicone carrier F containing no aminotin and the conductive fine powder being carbon black and containing an aminosilane coupling agent. As a result, clear high image quality was obtained, and the image did not change even after 200,000 images were put out.
[0069]
In addition, when the charge amount of the toner was measured by the blow-off method, the initial charge amount was −24.3 μc / g, and the charge amount of the toner after running 200,000 sheets was almost −23.8 μc / g, which was almost the initial value. There was no difference.
[0070]
Example 4
90 parts of polyester resin
10 parts of styrene-n-butyl methacrylate
Illustrative fluorine-containing compound a 2.5 parts
Metal-containing monoazo dye (Orient Chemical Co., Ltd. Bontron S-34) 3 parts
Carbon black 5 parts
In the same manner as in Example 1, the mixture having the above composition was sufficiently stirred and mixed in a Henschel mixer, heated and melted at a temperature of 130 to 140 ° C. for about 30 minutes with a roll mill, cooled to room temperature, and the obtained kneaded product was pulverized. Classification was performed to obtain a toner having a particle diameter of 5 to 20 μm. To 100 parts of this toner, 0.4 part of hydrophobic colloidal silica was sufficiently stirred and mixed with a speed kneader to obtain a toner.
[0071]
2.5 parts of this toner and 97.5 parts of silicone carrier F were mixed with a ball mill to obtain a developer. Further, when an image output test similar to that in Example 1 was performed, a clear high image quality was obtained, and the image did not change even after the 200,000 images were output.
[0072]
In addition, when the charge amount of the toner was measured by the blow-off method, the initial charge amount was −24.4 μc / g, and the toner charge amount after running 200,000 sheets was −23.9 μc / g, which was almost the same as the initial value. There was no difference. In addition, it shows a charge level that is not much different from room temperature, -24.2 μc / g in a high humidity environment of 35 ° C. and 90% RH, and −24.3 μc / g in a low humidity environment of 10 ° C. and 15% RH. was gotten.
[0073]
Further, when the storage stability of the PVC mat was tested in the same manner as in Example 1, the toner did not adhere to the mat, and the storage stability of the PVC mat was good.
[0075]
Example 5
A developer was obtained in the same manner as in Example 4 except that the silicone carrier G excluding the carrier aminosilane coupling agent in Example 4 was used, and an image test was performed. The initial image and the image after 80,000 sheets were clear images with no fog. When the charge amount was measured in the same manner as in Example 1, the initial charge amount was −16.1 μc / g, but after 80,000 sheets, it was stable at −15.5 μc / g.
[0076]
Example 6
100 parts of styrene-n-butyl methacrylate
Phthalocyanine blue 5 parts
Quaternary ammonium salt (Orient Chemical Co., Ltd. Bontron P-51) 2 parts
The mixture having the above composition was melt-kneaded with a hot roll at 120 ° C. and then cooled and solidified, and pulverized with a jet mill to obtain a toner having a particle diameter of 5 to 20 μm. Silicone carrier H and 97.5 parts were mixed with 2.5 parts of this toner by a ball mill to obtain a developer. When this developer was set in our copier FT7570 and subjected to an image test, a clear high image quality was obtained, and the image did not change even after 200,000 images were put out.
[0077]
Further, when the toner charge amount was measured by the blow-off method, the initial charge amount was +25.4 μc / g, and the toner charge amount after running 100,000 sheets was +24.9 μc / g, which is almost different from the initial value. There wasn't. Further, the thickness of the carrier coating film after 200,000 sheets was worn about 0.1 μm from the beginning.
[0078]
Comparative Example 4
A developer was obtained in the same manner as in Example 6 except that Carrier I except the carrier epoxysilane coupling agent in Example 6 was used, and an image test was performed. As the initial image, a clear image without fogging was obtained, but from around 10,000 sheets, it became a blurry image with fogging. When the charge amount was measured in the same manner as in Example 1, the initial charge amount was +20.1 μc / g, but after 30,000 sheets, it decreased to +6.3 μc / g. The thickness of the carrier coating film after 100,000 sheets was worn about 0.2 μm from the beginning.
[0079]
【The invention's effect】
As described above, by using a specific electrophotographic developing carrier and developer as in the present invention, an image having the same quality as the initial image can be obtained even after continuous copying, and stable triboelectric chargeability. And a clear copy image is obtained.

Claims (5)

In the carrier for electrophotographic development, this carrier has a silicone resin coating layer containing an organotin compound or a silane coupling agent and a conductive fine powder, and the Si—C bond and Si—O in the silicone resin coating layer. A carrier for developing an electrostatic latent image, wherein the bond ratio Si-C / Si-O is in the range of 0.15 to 0.35. 2. The negatively charged carrier for developing an electrostatic latent image according to claim 1, wherein the conductive fine powder is carbon black and the silane coupling agent is an aminosilane coupling agent. 2. The positively charged carrier for developing an electrostatic latent image according to claim 1, wherein the conductive fine powder is carbon black and the silane coupling agent is an epoxy silane coupling agent. In an electrophotographic developer comprising a carrier and a toner, the toner contains at least a polyester resin as a binder resin and a fluorine-containing quaternary ammonium salt compound represented by the following general formula as a polarity control agent, and the carrier is a conductive fine powder. A silicone resin coating layer containing Si, and a value of Si—C bond and Si—O bond ratio Si—C / Si—O in the silicone resin coating layer is in the range of 0.15 to 0.35. An electrostatic latent image two-component developer.
General formula (1)

R _{1 to} R ₄ : hydrogen atom or lower alkyl group having 1 to 10 carbon atoms, aryl group n: positive integer m: positive integer X: —CO, —SO ₂ 5. The two-component developer for developing an electrostatic latent image according to claim 4, wherein the silicone resin coating layer covering the carrier contains an aminosilane coupling agent.