JP2004109406A - Electrophotographic toner - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a toner which can deal with a grain size reduction, is stable in electrostatic charge, can prevent texture fogging, toner scattering, etc., and can be manufactured at a low cost by simple processes and to provide a developer. <P>SOLUTION: The dry electrophotographic toner has small particles uniformly sticking to the surfaces of host particles and is 0.95<q1/q2<1.60 when the electrostatic charge characteristics to a carrier is defined as [the electrostatic charge quantity of the small particles]=q1 and [the electrostatic charge quantity of the host particles]=q2. <P>COPYRIGHT: (C)2004,JPO

Description

【００２４】
（式中、Ｒ^１及びＲ^２は、同一でも異なっていてもよく、炭素数２〜４のアルキレン基であり、またｘ、ｙは繰り返し単位の数であり、各々１以上であって、ｘ＋ｙ＝２〜１６である。）
▲３▼３価以上の多価カルボン酸ならびにその低級アルキルエステル及び酸無水物、及び、３価以上の多価アルコールのいずれかから選ばれる少なくとも一種
上記▲１▼▲２▼▲３▼とを反応させてなるポリエステル樹脂であることが好ましい。
【００２５】
ここで、▲１▼の２価カルボン酸ならびにその低級アルキルエステル及び酸無水物の一例としては、テレフタル酸、イソフタル酸、セバシン酸、イソデシルコハク酸、マレイン酸、フマル酸及びこれらのモノメチル、モノエチル、ジメチル及びジエチルエステル、及び無水フタル酸、無水マレイン酸等があり、特にテレフタル酸、イソフタル酸及びこれらのジメチルエステルが耐ブロッキング性及びコストの点で好ましい。これらの２価カルボン酸ならびにその低級アルキルエステル及び酸無水物はトナーの定着性や耐ブロッキング性に大きく影響する。すなわち、縮合度にもよるが、芳香族系のテレフタル酸、イソフタル酸等を多く用いると耐ブロッキング性は向上するが、定着性が低下する。逆に、セバシン酸、イソデシルコハク酸、マレイン酸、フマル酸等を多く用いると定着性は向上するが、耐ブロッキング性が低下する。従って、他のモノマー組成や比率、縮合度に合わせてこれらの２価カルボン酸類が適宜選定され、単独又は組合わせて使用される。
【００２６】
▲２▼の前記一般式（Ｉ）で示されるジオール成分の一例としては、ポリオキシプロピレン−（ｎ）−ポリオキシエチレン−（ｎ′）−２，２−ビス（４−ヒドロキシフェニル）プロパン、ポリオキシプロピレン−（ｎ）−２，２−ビス（４−ヒドロキシフェニル）プロパン、ポリオキシエチレン−（ｎ）−２，２−ビス（４−ヒドロキシフェニル）プロパン等が挙げられるが、特に、２．１≦ｎ≦２．５であるポリオキシプロピレン−（ｎ）−２，２−ビス（４−ヒドロキシフェニル）プロパン及び２．０≦ｎ≦２．５であるポリオキシエチレン−（ｎ）−２，２−ビス（４−ヒドロキシフェニル）プロパンが好ましい。このようなジオール成分は、ガラス転移温度を向上させ、反応を制御し易くするという利点がある。
【００２７】
なお、ジオール成分として、エチレングリコール、ジエチレングリコール、１，２−ブタンジオール、１、３−ブタンジオール、１，４−ブタンジオール、ネオペンチルグリコール、プロピレングリコール等の脂肪族ジオールを使用することも可能である。
【００２８】
▲３▼の３価以上の多価カルボン酸ならびにその低級アルキルエステル及び酸無水物の一例としては、１，２，４−ベンゼントリカルボン酸（トリメリット酸）、１，３，５−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−ナフト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）メタン、１，２，７，８−オクタンテトラカルボン酸、エンポール三量体酸及びこれらのモノメチル、モノエチル、ジメチルおよびジエチルエステル等が挙げられる。
【００２９】
又、▲３▼の３価以上の多価アルコールの一例としては、ソルビトール、１，２，３，６−ヘキサンテトロール、１，４−ソルビタン、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−ペンタトリオール、グリセロール、ジグリセロール、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が挙げられる。
【００３０】
ここで、３価以上の多価単量体の配合割合は、単量体組成物全体の１〜３０モル％程度が適当である。１モル％以下の時には、トナーの耐オフセット性が低下し、また、耐久性も悪化しやすい。一方、３０モル％以上の時には、トナーの定着性が悪化しやすい。
【００３１】
これらの３価以上の多価単量体のうち、特にベンゼントリカルボン酸、これらの酸の無水物又はエステル等のベンゼントリカルボン酸類が好ましい。すなわち、ベンゼントリカルボン酸類を用いることにより、定着性と耐オフセット性の両立を図ることができる。
【００３２】
又、ポリオール樹脂としては、各種のタイプのものが使用できるが、特に、▲１▼エポキシ樹脂と、▲２▼２価フェノールのアルキレンオキサイド付加物もしくはそのグリシジルエーテルと、▲３▼エポキシ基と反応する活性水素を分子中に１個有する化合物と、▲４▼エポキシ基と反応する活性水素を分子中に２個以上有する化合物を反応してなるポリオール樹脂を用いることが好ましい。
【００３３】
ここで、▲１▼のエポキシ樹脂は、好ましくはビスフェノールＡやビスフェノールＦ等のビスフェノールとエピクロロヒドリンを結合して得られたものである。特に、エポキシ樹脂が安定した定着特性や光沢を得るために数平均分子量の相違する少なくとも２種以上のビスフェノールＡ型エポキシ樹脂で、低分子量成分の数平均分子量が３６０〜２０００であり、高分子量成分の数平均分子量が３０００〜１００００であることが好ましい。さらに低分子量成分が２０〜５０重量％、高分子量成分が５〜４０重量％であることが好ましい。低分子量成分が多すぎたり、分子量が３６０よりさらに低分子の場合は、光沢が出すぎたり、さらには保存性の悪化の可能性がある。また、高分子量成分が多すぎたり、分子量１００００よりさらに高分子の場合は、光沢が不足したり、さらには定着性の悪化の可能性がある。
【００３４】
又、▲２▼の化合物としての、２価フェノールのアルキレンオキサイド付加物としては、以下のものが例示される。即ち、エチレンオキサイド、プロピレンオキサイド、ブチレンオキサイド及びこれらの混合物とビスフェノールＡやビスフェノールＦ等のビスフェノールとの反応生成物が挙げられる。得られた付加物をエピクロロヒドリンやβ−メチルエピクロロヒドリン等でグリシジル化して用いてもよい。特に下記（ＩＩ）式で表わされるビスフェノールＡのアルキレンオキサイド付加物のジグリシジルエーテルが好ましい。
【００３５】
【化２】

【００３６】
（式中、Ｒは−ＣＨ_２−ＣＨ_２−、−ＣＨ_２−ＣＨ（ＣＨ_３）−又は−ＣＨ_２−ＣＨ_２−ＣＨ_２−基であり、またｎ、ｍは繰り返し単位の数であり、各々１以上であって、ｎ＋ｍ＝２〜６である。）
【００３７】
また、２価フェノールのアルキレンオキサイド付加物もしくはそのグリシジルエーテルが、ポリオール樹脂に対して１０〜４０重量％含まれていることが好ましい。ここで量が少ないとカールが増すなどの不具合が生じ、また、ｎ＋ｍが７以上であったり量が多すぎると、光沢が出すぎたり、さらには保存性の悪化の可能性がある。
【００３８】
又、▲３▼のエポキシ基と反応する活性水素を分子中に１個有する化合物としては、１価フェノール類、２級アミン類、カルボン酸類がある。１価フェノール類としては以下のものが例示される。即ち、フェノール、クレゾール、イソプロピルフェノール、アミノフェノール、ノニルフェノール、ドデシルフェノール、キシレノール、ｐ−クミルフェノール等が挙げられる。２級アミン類としては、ジエチルアミン、ジプロピルアミン、ジブチルアミン、Ｎ−メチル（エチル）ピペラジン、ピペリジン等が挙げられる。また、カルボン酸類としては、プロピオン酸、カプロン酸等が挙げられる。
【００３９】
又、▲４▼のエポキシ基と反応する活性水素を分子中に２個以上有する化合物としては、２価フェノール類、多価フェノール類、多価カルボン酸類が挙げられる。２価フェノール類としてはビスフェノールＡやビスフェノールＦ等のビスフェノールが挙げられる。また、多価フェノール類としてはオルソクレゾールノボラック類、フェノールノボラック類、トリス（４−ヒドロキシフェニル）メタン、１−〔α−メチル−α−（４−ヒドロキシフェニル）エチル〕ベンゼンが例示される。多価カルボン酸類としては、マロン酸、コハク酸、グルタル酸、アジピン酸、マレイン酸、フマル酸、フタル酸、テレフタル酸、トリメリット酸、無水トリメリット酸が例示される。
【００４０】
また、これらのポリエステル樹脂やポリオール樹脂は、高い架橋密度を持たせると、透明性や光沢度が得られにくくなるため、好ましくは、非架橋もしくは弱い架橋（ＴＨＦ不溶分が５％以下）であることが好ましい。
また、これらの結着樹脂の製造法は、特に限定されるものではなく、塊状重合、溶液重合、乳化重合、懸濁重合等のいずれも用いることが出来る。
【００４１】
次に、トナーに用いられる着色剤としては、従来公知の染料及び顔料が使用できる。
黄色系着色剤としては、例えば、ナフトールイエローＳ、ハンザイエロー（１０Ｇ、５Ｇ、Ｇ）、カドミュウムイエロー、黄色酸化鉄、黄土、黄鉛、チタン黄、ポリアゾイエロー、オイルイエロー、ハンザイエロー、（ＧＲ、Ａ、ＲＮ、Ｒ），ピグメントイエローＬ、ベンジジンイエロー（Ｇ、ＧＲ）、パーマネントイエロー（ＮＣＧ）、バルカンファストイエロー（５Ｇ、Ｒ）、タートラジンレーキ、キノリンイエローレーキ、アンスラザンイエローＢＧＬ、ベンズイミダゾロンイエロー、イソインドリノンイエロー等が挙げられる。
【００４２】
赤色系着色剤としては、例えば、ベンガラ、鉛丹、鉛朱、カドミュウムレッド、カドミュウムマーキュリレッド、アンチモン朱、パーマネントレッド４Ｒ、パラレッド、ファイヤーレッド、パラクロロオルトニトロアニリンレッド、リソールファストスカーレットＧ、ブリリアントファストスカーレット、ブリリアントカーミンＢＳ、パーマネントレッド（Ｆ２Ｒ、Ｆ４Ｒ、ＦＲＬ、ＦＲＬＬ、Ｆ４ＲＨ）、ファストスカーレットＶＤ、ベルカンファストルビンＢ、ブリリアントスカーレットＧ、リソールルビンＧＸ、パーマネントレッド（Ｆ５Ｒ、ＦＢＢ）、ブリリアントカーミン６Ｂ、ピグメントスカーレット３Ｂ、ボルドー５Ｂ、トルイジンマルーン、パ−マネントボルドーＦ２Ｋ、ヘリオボルドーＢＬ、ボルドー１０Ｂ、ボンマルーンライト、ボンマルーンメジアム、エオシンレーキ、ローダミンレーキＢ、ローダミンレーキＹ、アリザリンレーキ、チオインジゴレッドＢ、チオインジゴマルーン、オイルレッド、キナクリドンレッド、ピラゾロンレッド、ポリアゾレッド、クロームバーミリオン、ベンジジンオレンジ、ペリノンオレンジ、オイルオレンジ等が挙げられる。
【００４３】
青色系着色剤としては、例えば、コバルトブルー、セルリアンブルー、アルカリブルーレーキ、ピーコックブルーレーキ、ビクトリアブルーレーキ、無金属フタロシアニンブルー、フタロシアニンブルー、ファストスカイブルー、インダンスレンブルー（ＲＳ、ＢＣ）、インジゴ、群青、紺青、アントラキノンブルー、ファストバイオレットＢ、メチルバイオレットレーキ、コバルト紫、マンガン紫、ジオキサンバイオレット、アントラキノンバイオレット、クロムグリーン、ジンクグリーン、酸化クロム、ピリジアン、エメラルドグリーン、ピグメントグリーンＢ，ナフトールグリーンＢ、グリーンゴールド、アシッドグリーンレーキ、マラカイトグリーンレーキ、フタロシアニングリーン、アントラキノングリーン等が挙げられる。
【００４４】
黒色系着色剤としては、例えば、カーボンブラック、オイルファーネスブラック、チャンネル　ブラック、ランプブラック、アセチレンブラック、アニリンブラック等のアジン系色素、金属塩アゾ色素、金属酸化物、複合金属酸化物等が挙げられる。
その他の着色剤としては、チタニア、亜鉛華、リトボン、ニグロシン染料、鉄黒等が挙げられる。
これらの着色剤は、単独あるいは２種類以上組み合わせて用いることができ、含有量は、結着樹脂１００重量部に対して、通常１〜３０重量部、好ましくは３〜２０重量部である。
【００４５】
又、本発明に用いられるトナーには、必要に応じて、帯電制御剤、離型剤等の他の材料を添加することが出来る。
ここで、帯電制御剤としては、従来公知のものが使用でき、例えば、ニグロシン染料、含クロム錯体、第４級アンモニウム塩等が挙げられ、これらはトナー粒子の極性により使い分ける。特に、カラートナーの場合、トナーの色調に影響を与えない無色又は淡色のものが好ましく、例えば、サリチル酸金属塩又はサリチル酸誘導体の金属塩（ボントロンＥ８４、オリエント社製）等が挙げられる。
これらの帯電制御剤は、単独あるいは２種類以上組み合わせて用いることができ、含有量は、結着樹脂１００重量部に対して、通常０．５〜８重量部、好ましくは１〜５重量部である。
【００４６】
また、定着時における定着部材からのトナーの離型性を向上させ、またトナーの定着性を向上させるために、離型剤をトナー中に含有させることも可能である。
ここで、離型剤としては、従来公知のものが使用でき、例えば、低分子量ポリエチレン、低分子量ポリプロピレン等の低分子量ポリオレフィンワックス、フィッシャー・トロプシュワックス等の合成炭化水素系ワックス、密ロウ、カルナウバワックス、キャンデリラワックス、ライスワックス、モンタンワックス等の天然ワックス類、パラフィンワックス、マイクロクリスタリンワックス等の石油ワックス類、ステアリン酸、パルミチン酸、ミリスチン酸等の高級脂肪酸及び高級脂肪酸の金属塩、高級脂肪酸アミド等及びこれらの各種変性ワックス等が挙げられる。
【００４７】
これらの離型剤は、単独あるいは２種類以上組合わせて用いることができるが、特にカルナウバワックスを使用することにより良好な離型性を得ることができる。
又、離型剤の含有量は、結着樹脂１００重量部に対して、通常１〜１５重量部、好ましくは、２〜１０重量部である。１重量部以下ではオフセット防止効果等が不十分であり、１５重量部以上では転写性、耐久性等が低下する。
【００４８】
更に、本発明に用いられるトナーは、磁性体を含有させ、磁性トナーとして用いることもできる。
具体的な磁性体としては、マグネタイト、ヘマタイト、フェライト等の酸化鉄、コバルト、ニッケルのような金属、あるいはこれら金属とアルミニウム、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との合金およびその混合物等が挙げられる。
【００４９】
これらの磁性体は平均粒径が０．１〜２μｍ程度のものが好ましく、含有量は、結着樹脂１００重量部に対して、通常２０〜２００重量部、好ましくは４０〜１５０重量部である。
【００５０】
本発明に用いられる小粒子としては、１種または複数の樹脂粒子を目的に応じて選択し、使用することが出来る。特に母体粒子と同じ樹脂を使用すると小粒子の接着性が高く好ましい。　定着性、耐熱性、耐凝集性を考慮すると母体よりも軟化点の高い樹脂を選択すると良い。
【００５１】
具体的には、原料として、ビニル系単量体、例えばスチレン、ｏ−メチルスチレン、ｍ−メチルスチレン、ｐ−メチルスチレン、ｐ−エチルスチレン、２，４−ジメチルスチレン、ｐ−ｎ−ブチルスチレン、ｐ−ｔ−ブチルスチレン、ｐ−ｎ−ヘキシルスチレン、ｐ−ｎ−オクチルスチレン、ｐ−ｎ−ノニルスチレン、ｐ−ｎ−デシルスチレン、ｐ−ｎ−ドデシルスチレン、ｎ−メトキシスチレン、ｐ−フェニルスチレン、ｐ−クロロスチレン、３，４−ジクロロスチレン等のスチレン系単官能性単量体、エチレン、プロピレン、ブチレン、イソブチレン等のエチレン系不飽和モノオレフィン類、塩化ビニル、塩化ビニリデン、臭化ビニル、弗化ビニル等のハロゲン化ビニル類、酢酸ビニル、プロピオン酸ビニル、安息香酸ビニル、酪酸ビニル等のビニルエステル、アクリル酸メチル、アクリル酸エチル、アクリル酸プロピル、アクリル酸ｎ−ブチル、アクリル酸イソブチル、アクリル酸ｎ−オクチル、アクリル酸ドデシル、アクリル酸２−エチルヘキシル、アクリル酸ステアリル、アクリル酸２−クロロエチル、アクリル酸フェニル、α−クロロアクリル酸メチル、メタクリル酸エチル、メタクリル酸プロピル、メタクリル酸ｎ−ブチル、メタクリル酸イソブチル、メタクリル酸ｎ−オクチル、メタクリル酸ドデシル、メタクリル酸２−エチルヘキシル、メタクリル酸ステアリル、メタクリル酸フェニル、アクリル酸ジメチルアミノエチル、メタクリル酸ジエチルアミノエチル等のα−メチレン脂肪族モノカルボン酸エステル類、アクリロニトリル、メタクリロニトリル、アクリルアミド、メタクリルアミドなどが使用され、場合によってはアクリル酸、メタクリル酸、マレイン酸、フマール酸等の不飽和カルボン酸、ビニルメチルエーテル、ビニルエチルエーテル、ビニルイソブチルエーテル等のビニルエーテル類、アクリル酸２−ヒドロキシエチル、メタクリル酸２−ヒドロキシエチル、メタクリル酸２−ヒドロキシプロピル等のアクリル酸もしくはメタクリル酸誘導体、ビニルメチルケトン、ビニルヘキシルケトン、メチルイソプロペニルケトン等のビニルケトン類、Ｎ−ビニルピロール、Ｎ−ビニルカルバゾール、Ｎ−ビニルインドール、Ｎ−ビニルピロリドン等のＮ−ビニル化合物、ビニルナフタリン塩等、ジビニルベンゼン、ジビニルナフタレン及びそれらの誘導体のような芳香族ジビニル化合物、アリルメタクリレート、エチレングリコールジメタクリレート、ジエチレングリコールジメタクリレート、トリエチレングリコールトリアクリレート、トリメチロールプロパントリアクリレート、１，６−ヘキサンジオールジメタクリレート、トリメチロールプロパントリメタクリレート、ペンタエリスリトールテトラメタクリレート、Ｎ，Ｎ−ジビニルアニリン、ジビニルエーテル及びジビニルスルファイト等から製造したものなどを使用できる。これらは単独重合または共重合して用いられる。
【００５２】
次に、本発明に用いられるトナーの製造例の一例を以下に述べる。
▲１▼　前述した結着樹脂、着色剤、又は必要に応じて帯電制御剤、離型剤、磁性体等をヘンシェルミキサーの如き混合機により十分に混合する。
▲２▼　バッチ式の２本ロール、バンバリーミキサーや連続式の２軸押出し機、例えば神戸製鋼所社製ＫＴＫ型２軸押出し機、東芝機械社製ＴＥＭ型２軸押出し機、ＫＣＫ社製２軸押出し機、池貝鉄工社製ＰＣＭ型２軸押出し機、栗本鉄工所社製ＫＥＸ型２軸押出し機や、連続式の１軸混練機、例えばブッス社製コ・ニーダ等の熱混練機を用いて構成材料を十分に混練する。
▲３▼　混練物を冷却後、ハンマーミル等を用いて粗粉砕し、更にジェット気流を用いた微粉砕機や機械式粉砕機により微粉砕し、旋回気流を用いた分級機やコアンダ効果を用いた分級機により所定の粒度に分級し、母体粒子を得る。
【００５３】
又、その他の製造法として、重合法、カプセル法等を用いることも可能である。これらの製造法の概略を以下に述べる。
【００５４】
（重合法）
▲１▼　重合性モノマー、必要に応じて重合開始剤、着色剤等を水性分散媒中で造粒する。
▲２▼　造粒されたモノマー組成物粒子を適当な粒子径に分級する。
▲３▼　上記分級により得た規定内粒径のモノマー組成物粒子を重合させる。
▲４▼　適当な処理をして分散剤を取り除いた後、上記により得た重合生成物をろ過、水洗、乾燥して母体粒子を得る。
【００５５】
（カプセル法）
▲１▼　樹脂、必要に応じて着色剤等を混練機等で混練し、溶融状態のトナー芯材を得る。
▲２▼　トナー芯材を水中に入れて強く撹拌し、微粒子状の芯材を作成する。
▲３▼　シェル材溶液中に上記芯材微粒子を入れ、撹拌しながら、貧溶媒を滴下し、芯材表面をシェル材で覆うことによりカプセル化する。
▲４▼　上記により得たカプセルをろ過後、乾燥して母体粒子を得る。
【００５６】
ついで、該母体粒子と添加剤をヘンシェルミキサー（三井三池社製）、メカノフュージョンシステム（細川ミクロン社製）、メカノミル（岡田精工社製）等の混合機により十分混合し、必要に応じて、１５０μｍ程度以下の目開きの篩を通過させ、凝集物や粗大粒子等の除去を行う。
【００５７】
ここで、添加剤としては、従来公知のものが使用でき、例えば、Ｓｉ，Ｔｉ，Ａｌ，Ｍｇ，Ｃａ，Ｓｒ，Ｂａ，Ｉｎ，Ｇａ，Ｎｉ，Ｍｎ，Ｗ，Ｆｅ，Ｃｏ，Ｚｎ，Ｃｒ，Ｍｏ，Ｃｕ，Ａｇ，Ｖ，Ｚｒ等の酸化物や複合酸化物等が挙げられ、特にＳｉ，Ｔｉ，Ａｌの酸化物であるシリカ、チタニア、アルミナが好適に用いられる。
【００５８】
また、このときの添加剤の添加量は、母体粒子１００重量部に対して、０．６〜４．０重量部であることが好ましく、特に好ましくは、１．０〜３．６重量部である。
添加剤の添加量が、０．６重量部未満であると、トナーの流動性が低下するため、十分な帯電性が得られず、また、転写性や耐熱保存性も不十分となり、また、地汚れやトナー飛散の原因にもなりやすい。
【００５９】
また４．０重量部より多いと、流動性は向上するものの、ビビリ、ブレードめくれ等の感光体クリーニング不良や、トナーから遊離した添加剤による感光体等へのフィルミングが生じやすくなり、クリーニングブレードや感光体等の耐久性が低下し、定着性も悪化する。
【００６０】
ここで、添加剤の含有量の測定には種々の方法があるが、蛍光Ｘ線分析法で求めるのが一般的である。すなわち、添加剤の含有量既知のトナーについて、蛍光Ｘ線分析法で検量線を作成し、この検量線を用いて、添加剤の含有量を求めることができる。
さらに、添加剤は、必要に応じ、疎水化、流動性向上、帯電性制御等の目的で、表面処理を施されていることが好ましい。
【００６１】
ここで、表面処理に用いる処理剤としては、有機系シラン化合物等が好ましく、例えば、メチルトリクロロシラン、オクチルトリクロロシラン、ジメチルジクロロシラン等のアルキルクロロシラン類、ジメチルジメトキシシラン、オクチルトリメトキシシラン等のアルキルメトキシシラン類、ヘキサメチルジシラザン、シリコーンオイル等が挙げられる。
【００６２】
又、処理方法としては、有機シラン化合物を含有する溶液中に添加剤を浸積し乾燥させる方法、添加剤に有機シラン化合物を含有する溶液を噴霧し乾燥させる方法等があるが、本発明においては、いずれの方法も好適に用いることができる。
【００６３】
さらに、母体粒子に添加される添加剤の粒径は、流動性付与等の点から、平均一次粒子径で０．００２〜０．２μｍであることが好ましく、特に好ましくは、０．００５〜０．０５μｍである。
【００６４】
平均一次粒子径が０．００２μｍより小さい添加剤は、母体粒子表面に添加剤が埋め込まれやすくなるため、凝集を生じやすく、又、流動性も十分に得られない。さらに、感光体等へのフィルミングも発生しやすくなり、これらの傾向は特に高温高湿下において顕著である。加えて、平均一次粒子径が０．００２μｍより小さいと、どうしても添加剤同士の凝集が生じやすくなるため、これによっても、十分な流動性が得られにくくなる。
【００６５】
又、平均一次粒子径が０．２μｍより大きい添加剤は、トナーの流動性が低下するため、十分な帯電性が得られず、地汚れやトナー飛散の原因になりやすい。又、平均一次粒子径が０．１μｍより大きい添加剤は、感光体表面を傷つけやすく、フィルミング等の原因にもなりやすい。
なお、添加剤の粒径は、透過型電子顕微鏡により測定して求めることが出来る。
【００６６】
本発明に用いられるトナーには、前記の添加剤の他に、さらに他の添加剤を添加させることもできる。このような添加剤としては、例えば、滑剤として、テフロン（登録商標）、ステアリン酸亜鉛及びポリ弗化ビニリデン等が、研磨剤として、酸化セリウム、炭化ケイ素及びチタン酸ストロンチウム等が、導電性付与材として、酸化亜鉛、酸化アンチモン及び酸化スズ等が、それぞれ挙げられる。
【００６７】
また、本発明に用いられるトナーの粒径は、重量平均径で４〜９μｍであることが好ましく、特に好ましくは、５〜８μｍである。
ここで、４μｍよりも小粒径の場合には、現像時に地汚れやトナー飛散等が生じたり、流動性を悪化させトナーの補給やクリーニング性等を阻害する場合がある。また、８μｍよりも大粒径の場合には、画像中のチリや、解像性の悪化等が問題となる場合があり、特に、カラー画像の場合においては、その影響が大きい。
【００６８】
本発明に用いられるトナーは、一成分トナー及び二成分トナーの双方に適用可能である。二成分トナーの場合にはキャリアと混合されて二成分現像剤として使用される。
ここで、キャリアとしては、従来公知のものが使用でき、例えば、鉄粉、フェライト粉、ニッケル粉のごとき磁性を有する粉体、及び、ガラスビーズ等が挙げられ、特に、これらの表面を樹脂等で被覆することが好ましい。
【００６９】
この場合、使用される樹脂としては、ポリフッ化炭素、ポリ塩化ビニル、ポリ塩化ビニリデン、フェノール樹脂、ポリビニルアセタール、アクリル樹脂、シリコーン樹脂等が挙げられる。
又、この樹脂層の形成法としては、従来と同様、キャリアの表面に噴霧法、浸漬法等の手段で樹脂を塗布すればよい。
なお、樹脂の使用量としては、通常キャリア１００重量部に対して１〜１０重量部が好ましい。
【００７０】
また、樹脂の膜厚としては、０．０２〜２μｍであることが好ましく、特に好ましくは０．０５〜１μｍ、更に好ましくは、０．１〜０．６μｍであり、膜厚が厚いとキャリア及び現像剤の流動性が低下する傾向にあり、膜厚が薄いと経時での膜削れ等の影響を受けやすい傾向にある。
ここで、これらのキャリアの平均粒径は通常１０〜１００μｍ、好ましくは３０〜６０μｍである。
【００７１】
さらに、トナーとキャリアとの混合割合は、一般にキャリア１００重量部に対しトナー０．５〜７．０重量部程度が適当である。
【００７２】
（円形度）
本発明に用いられる円形度である形状係数ＳＦ−１、ＳＦ−２は、日立製作所製ＦＥ−ＳＥＭ（Ｓ−４２００）により測定して得られたトナーのＳＥＭ像を３００個無作為にサンプリングし、その画像情報をインターフェースを介してニレコ社製画像解析装置（Ｌｕｚｅｘ　ＡＰ）に導入し解析を行い、下式より算出し得られた値をＳＦ−１、ＳＦ−２と定義した。ＳＦ−１、ＳＦ−２の値はＬｕｚｅｘにより求めた値が好ましいが、同様の解析結果が得られるのであれば特に上記ＦＥ−ＳＥＭ装置、画像解析装置に限定されない。
【００７３】
ＳＦ−１＝（Ｌ^２／Ａ）×（π／４）×１００
ＳＦ−２＝（Ｐ^２／Ａ）×（１／４π）×１００
ここで、
トナーの絶対最大長をＬ
トナーの投影面積をＡ
トナーの最大周長をＰ
とする。真球であればいずれも１００となり、１００より値が大きくなるにつれて球形から不定形になる。また特にＳＦ−１はトナー全体の形状（楕円や球等）を表し、ＳＦ−２は表面の凹凸程度を示す形状係数となる。
【００７４】
＜トナーの製造例＞
実施例　１

上記原材料をヘンシェルミキサーにて混合し、顔料凝集体中に水が染み込んだ混合物を得た。これをロ−ル表面温度１２８℃に設定した２本ロールにより４５分間混練を行ない、圧延冷却しパルペライザーで粉砕、マスターバッチ着色剤を得た。
【００７５】

上記材料をミキサーで混合後、２本ロールミルで５回溶融混練し、混練物を圧延冷却した。その後ジェットミルによる衝突板方式の粉砕機（Ｉ式ミル；日本ニューマチック工業社製）と旋回流による風力分級（ＤＳ分級機；日本ニューマチック工業社製）を行い、体積平均粒径５．５μｍ、個数平均粒径４．５μｍのマゼンタ色のトナー母体粒子Ａを得た。
【００７６】
（小粒子製造例）　撹拌装置、滴下ロート、チッ素導入官、冷却官及び温度計を備えたフラスコにイオン交換水９５部を仕込み、昇温、チッ素置換の後、温度を６５℃に保ち回転数２００ｒｐｍで撹拌を行ない、スチレン４０部、アクリル酸ｎ−ブチル２０部の混合物を４時間かけて滴下した。また、イオン交換水５部に溶解した過硫酸カリウム０．１４部を、６時間かけて添加した。この後１１時間加熱した後、８０℃で３時間加熱し重合を終了した。　得られた微粒子をフラスコ中でボントロンＥ８４の９０℃飽和溶液に分散し、この溶液全体を３０℃に急冷し、樹脂粒子表面にボントロンＥ８４を析出させ、小粒子Ｂを得た。
【００７７】
この時の重合率は９７％で、粒径は０．４２μｍであった。また、乾燥粒子のガラス転移点は７０℃であった。乾燥は重合液を凍結し、減圧乾燥を行なった。母体粒子Ａ　９７部と小粒子Ｂ　３部をハイブリダイゼーションシステム［（株）奈良機械製作所ＮＨＳ−Ｏ］により、１２０００ｒｐｍで２分間処理して固定化を行ない、トナーＣを作成した。　母体粒子表面の小粒子による被覆率は電子顕微鏡観察により　約９０％であった。
【００７８】
実施例　２
トナーの製造法を以下の乳化重合法に変更した。
まず、樹脂分散液１として、
スチレン　　　　　　　　　　　　　　　　　　　　　　　　　３５０部
アクリル酸ブチル　　　　　　　　　　　　　　　　　　　　　　４１部
アクリル酸　　　　　　　　　　　　　　　　　　　　　　　　　　９部
ドデシルメルカプタン　　　　　　　　　　　　　　　　　　　　１６部
四臭化炭素　　　　　　　　　　　　　　　　　　　　　　　　　　５部
（以上いずれも和光純薬社製）
【００７９】
以上を混合溶解したものを非イオン性界面活性剤（三洋化成社製、ノニボール８５）９部、アニオン性界面活性剤（第一工業製薬社製、ネオゲンＳＣ）１１部をイオン交換水５８２部に溶解してフラスコ中で分散、乳化し１５分ゆっくりと混合しながら、過硫酸アンモニウム（東海電化社製）３．４ｇを溶解したイオン交換水５０ｇを投入し、窒素置換を行った。その後フラスコを攪拌しながらオイルバスで内容物が７３℃になるまで加熱し、７時間そのまま乳化重合を継続し、その後室温まで冷却し樹脂分散液を得た。得られた樹脂分散液から溶媒を８０℃のオーブン上に放置し水分を除去した。中心粒径１２０ｎｍ、ガラス転移点５５℃、Ｍｗ２２，０００の樹脂分散液１を得た。
【００８０】
顔料Ｐｉｇｍｅｎｔ　Ｒｅｄ　１２２、７０部をアニオン性界面活性剤（三洋化成社製、イオネットＤ−２）２部と共にイオン交換水３００部中に添加混合し、ＩＫＡ製ウルトラタラックスＴ５０にて分散処理し、中心径１６０ｎｍの顔料分散液１を得た。
ワックス（脂肪酸エステルワックス、融点８３℃、粘度２８０ｍＰａ・ｓ（９０℃））５０部をアニオン性界面活性剤（三洋化成社製、イオネットＤ−２）２部と共にイオン交換水３００部中に添加混合し、ＩＫＡ製ウルトラタラックスＴ５０にて分散処理し、ワックス分散液１を得た。
【００８１】
次に上記の樹脂分散液１、顔料分散液１、ワックス分散液１を以下の割合で、
イオン交換水　　　　　　　　　　　　　　　　　　　　３００部
樹脂分散液１　　　　　　　　　　　　　　　　　　　　２４０部
顔料分散液１　　　　　　　　　　　　　　　　　　　　　４０部
ワックス分散液１　　　　　　　　　　　　　　　　　　　３５部
カチオン性界面活性剤　　　　　　　　　　　　　　　　　　２部
（花王社製、サニゾールＢ５０）
【００８２】
丸形ステンレス製フラスコ中にウルトラタラックスＴ５０で混合分散した後、加熱用オイルバスでフラスコを攪拌しながら４８℃まで加熱した。４８℃で４時間保持した後、光学顕微鏡にて観察すると約５．５μｍの凝集粒子が生成していることが確認された。その後、ネオゲンＳＣを６部を追添加した後、攪拌を継続しながら９３℃まで加熱し、９時間保持した。この後フラスコを１０℃／分で室温まで冷却し、更に濾過した後、イオン交換水で充分洗浄後、真空乾燥機内で５０℃、１２時間保持し、体積平均粒径は５．５μｍ、個数平均粒径は４．７μｍ、分子量Ｍｗは２２，０００のマゼンタトナー母粒子Ｄを得た。
母体粒子Ｄ　９７部と小粒子Ｂ　３部をハイブリダイゼーションシステム［（株）奈良機械製作所ＮＨＳ−Ｏ］により、１２０００ｒｐｍで２分間処理して固定化を行ない、トナーＥを作成した。また、トナーの円形度ＳＦ−１は１０８、ＳＦ−２は１０５であった。
【００８３】
＜キャリアの製造例＞

【００８４】
上記コート材を１０分間スターラーで分散してコート液を調整し、このコート液と芯材を流動床内に回転式底板ディスクと攪拌羽根を設けた旋回流を形成させながらコートを行うコーティング装置に投入して、当該コート液を芯材上に塗布した。
さらに、得られたキャリアを電気炉で２５０℃で２時間焼成を行い、製造例のキャリア（膜厚：０．５μｍ）を得た。
【００８５】
小粒子Ｂのキャリアに対する帯電量はトナー濃度５．０ｗｔ％のときに−３０μＣ／ｇであり、母体トナー粒子Ｄのキャリアに対する帯電量は小粒子濃度５．０ｗｔ％のときに−２５μＣ／ｇであり、ｑ１／ｑ２＝１．２０であった。
母体トナー粒子Ｄのキャリアに対する帯電量は小粒子濃度５．０ｗｔ％のときに−２０μＣ／ｇであり、ｑ１／ｑ２＝１．５０であった。
【００８６】
＜現像剤の製造例＞
上記製造例、添加剤混合済みのトナー５部と、上記製造例のキャリア９５部をターブラーミキサーで混合し、現像剤を得た。
【００８７】
以下のプリンターを評価に使用した
（株）リコー製　ＩｍａｇｉｏＭＦ１３４０を用いた。トナー濃度６％で使用。
製造例で製造した現像剤とトナーを用いて、１万枚の印刷を行った。
その間の印刷画像の地肌汚れと、１万枚終了後のプリンター内部のトナー飛散程度を評価した。
【００８８】
本発明のトナーはいずれも良好な画像形成を行った。地肌の濃度の１万枚後と初期の濃度差はＸ−ＲＩＴＥによる測定で、０．０２以内であった。
また、１万枚後のプリンター内部のトナー飛散もほとんど見られなかった。プリント画像として、画像面積の多い写真画像を連続して使用した場合にも、得られた画像の地肌汚れは見られなかった。[0001]
[Prior art]
Development methods such as electrophotography and electrostatic recording include liquid development methods using a developer in which various pigments and dyes are finely dispersed in an insulating liquid, and dry development methods such as a cascade method, a magnetic brush method, and a powder cloud method. The present invention relates to an electrostatic image developing toner used in the latter dry developing method. Conventionally, this toner is manufactured by melting and mixing a colorant and a charge control agent in a thermoplastic resin with a kneader, cooling, pulverizing with a pulverizing device such as a jet mill, and classifying into a desired particle size distribution with an air classifier. Have been. As a means for directly producing a toner by a polymerization method without using this method, methods described in JP-B-36-10231, JP-B-47-5183, JP-B-53-17737, and the like have been proposed. I have.
[0002]
The charging properties of electrostatographic toners are a major concern in toner formulations. These properties control the behavior at the development station, as well as the toning and transfer processes. Since the first toner was manufactured, organic and metal organic compounds have been used as charge control agents for controlling the amount of electrostatic charge on the surface of toner particles. A usual method for introducing these into the toner is a method in which they are melt-blended with the toner polymer during the blending step of toner production. The charge control agent is usually used in an amount of 0.5 to 5% by weight based on the toner polymer. Some of these charge control agents are expensive chemicals. The only effective part of the charge control agent is the toner surface. This is because the toner particles come into contact with the carrier particles and the photoconductive layer in the developer. In addition, these charge control agents are often difficult to disperse uniformly in the toner particles, resulting in poor developer behavior, including splashing, short developer life, and unstable charge. .
[0003]
Japanese Patent Publication No. 59-38583 proposes a toner in which a coating layer composed of latex particles is formed on the surface of core particles produced by suspension polymerization. Other patents describe methods for embedding small particles on the toner surface. U.S. Pat. No. 4,950,573 discloses a method of embedding small organic polymer particles in heat fusible toner particles to improve low temperature fusing performance. U.S. Pat. No. 4,900,647 describes a method of embedding modifier particles in toner particles using mechanical impact. However, these methods may cause surface particles to be embedded at an uneven depth or to be unevenly distributed on the toner particle surface as a result of accumulation in depressions and gaps on the toner surface. Further, such mechanical fusing methods can cause heating of the toner particles, resulting in their aggregation. In addition, these methods require that the additive small particles be in a dry, non-agglomerated state, which is often difficult to achieve with particles less than 0.1 μm in diameter.
[0004]
In JP-A-5-341570, the toner particles have water-dispersible small particles strongly adhered to the surface thereof in a uniform distribution state, the small particles have an average diameter of 0.01 μm to 0.2 μm, and The particles adhere to the toner particles by a step of mixing the aqueous dispersion of the small particles with the toner particles, a step of stirring the resulting mixture to ensure uniform distribution, and a step of drying the toner particles. It has been suggested that. Further, the aqueous dispersion contains a charge control agent. In this method, the charge control agent is merely passed through the solution, and the distribution of the charge control agent attached to the toner surface is not controlled. Therefore, the charge amount distribution of the toner tends to be wide.
[0005]
[Problems to be solved by the invention]
However, the conventional method of melt-mixing a thermoplastic resin and a colorant and then pulverizing the same involves the disadvantage that the process is complicated and the cost is high, and that fogging and toner scattering due to a decrease in fluidity and a non-uniform composition are likely to occur. It has disadvantages. In the above-mentioned polymerization method which solves this drawback, a surfactant, a water-soluble polymer substance, an inorganic fine powder and the like are frequently used as a dispersion stabilizer, and as a result, a part thereof remains on the toner surface, resulting in low moisture resistance and low electrification. It has the disadvantage that its properties are very unstable. The toner described in JP-B-59-38583, which has been developed to solve these drawbacks, has a low compatibility between the coating layer and the colored nucleus particles at the time of fixing, resulting in poor transparency of the printed matter and poor toning. There is a problem of inhibition. In particular, in a full-color toner, the quality of toning is an important issue that governs image quality. In Japanese Patent Application Laid-Open No. 5-341570, the distribution of the charge control agent cannot be fully controlled, and the charge amount distribution tends to be wide.
[0006]
The present invention solves such a problem, and is an excellent toner which can be manufactured at a low cost by a simple process, can cope with a small particle size, is stable in charge, and prevents problems such as background fogging and toner scattering. And a developer.
[0007]
[Means for Solving the Problems]
The present inventors have conducted intensive studies and found that in a toner having small particles on the surface of the toner base particles, it is important that the charge amounts of both particles with respect to the carrier have a specific relationship. Reached.
[0008]
That is, the present invention
(1) An electrophotographic toner having small particles uniformly attached to the surface of base particles, and having a charge characteristic for a carrier of small particle charge = q1 and base particle charge = q2,
0.95 <q1 / q2 <1.60
A dry type electrophotographic toner,
(2) The dry electrophotographic toner according to the above (1), wherein a charge controlling agent is dispersed in the small particles.
(3) The toner for dry electrophotography according to the above (1) or (2), wherein a polarity controlling agent is attached to the surface of the small particles.
[0009]
(4) The toner for dry electrophotography according to the above (3), wherein a water-soluble compound is used as the charge control agent.
(5) The toner according to (3), wherein the toner or the small particles are dispersed in a supersaturated solution of the charge control agent, and the solution is cooled to precipitate the charge control agent and adhere the charge control agent to the surface of the small particles. ) Or (4).
(6) The dry electrophotographic toner as described in any one of (1) to (5) above, wherein the mother particle surface coverage of the small particles is 80% or more.
[0010]
(7) The dry electrophotographic toner according to any one of (1) to (6), wherein the average particle size of the small particles is 0.1 to 0.8 μm.
(8) The base particles are obtained by polymerization, and the toner particles after the attachment of the small particles have a circularity SF-1 value of 100 to 140 and a circularity SF-2 value of 100 to 130. The dry electrophotographic toner according to the above (1), wherein
(9) The toner or small particles are dispersed in a supersaturated solution of the charge control agent, and the charge control agent is precipitated by cooling the solution, and the charge control agent is attached to the surface of the small particles. Or the method for producing a toner according to (4).
(10) An image forming method using the toner according to (1) to (8).
[0011]
The toner of the present invention has a charge characteristic with respect to the carrier when the small particle charge amount is q1 and the base particle charge amount is q2.
A dry toner, wherein 0.95 <q1 / q2 <1.60. More preferably, 1.10 <q1 / q2 <1.50.
If it is out of this range, the distribution of the charge amount is likely to be widened, and particularly when the toner is replenished, the weakly charged toner and the oppositely charged toner are likely to be generated.
[0012]
In addition, in order to stabilize the charging of the small particles, it is manufactured by dispersing a charge controlling agent. In the case of manufacturing in this way, the amount of the charge control agent can be reduced because the toner can be selectively arranged on the toner surface. Although it is difficult to uniformly disperse the charge control agent in the toner, the charge control agent can be forcibly disposed on the toner surface, so that the charge stability of the toner can be improved.
[0013]
Since the resin particles are held in a convex shape on the surface of the toner, the resin particles are easily brought into contact with the carrier, and high charge is easily obtained. Therefore, when new toner is replenished to the developer, the rise of charging tends to be quick.
[0014]
If a toner is obtained by attaching a charge control agent to the surface of the small particles, the amount of the charge control agent can be further reduced. Since the probability that the charge control agent is present on the surface of the particles can be remarkably improved as compared with the case where the particles are dispersed inside the small particles, the charge stability and the rise of the charge of the toner can be improved.
[0015]
In the toner of the present invention, when a water-soluble compound is used as a charge control agent, the charge rise is particularly fast and stable. Although the reason is not clear, it is considered that adhesion stability to the surface of the small particles is excellent.
[0016]
As a method for producing the toner of the present invention, various known methods can be appropriately selected. In particular, the toner or small particles are dispersed in a supersaturated solution of the charge control agent, and the solution is cooled to precipitate the charge control agent, and the charge control agent is attached to the surface of the small particles to increase the amount of the charge control agent attached. In addition, the spread of the charge amount distribution can be suppressed. Depending on the conditions of the deposition, when the method for depositing a charge control agent by deposition is used, the deposition rate in the solution becomes uniform, and the amount of the charge control agent deposited on the surface of each toner or small particle is reduced. It is considered to be homogeneous.
[0017]
The toner of the present invention has small particles uniformly attached to the surface of the base particles.
When the mother particle surface coverage of the small particles is 80% or more, the charging characteristics and the fluidity of the toner are easily stabilized. It is considered that the stability is hindered when the exposure rate of the surface of the mother body having a difference in charging characteristics increases.
[0018]
The average particle size of the small particles is preferably from 0.1 to 0.8 μm. If it is too small, it is likely to be buried inside the mother when agitated with the carrier in the electrophotographic apparatus, and the rate of exposing the mother's surface becomes relatively high. Conversely, if the small particles are too large, the charge tends to concentrate on the surface of the small particles distant from the center of the toner, and side effects such as a decrease in fluidity start to occur.
[0019]
When the base particles are obtained by polymerization and the circularity SF-1 value of the toner particles after the small particles are adhered is 100 to 140 and the circularity SF-2 value is 100 to 130, the charging characteristics and the flowability are improved. Improvement can be simultaneously stabilized.
[0020]
The toner is obtained by externally adding an additive or the like to base particles containing a binder resin, a coloring agent, and other materials such as a charge control agent and a release agent, if necessary.
[0021]
As the binder resin used in the toner, conventionally known binder resins can be used. For example, polystyrene, styrene-butadiene copolymer, styrene-vinyl chloride copolymer, styrene-acrylate copolymer, styrene-methacrylic Acid ester copolymer, acrylic resin, polyester resin, epoxy resin, polyol resin, rosin-modified maleic acid resin, phenol resin, low molecular weight polyethylene, low molecular weight polypropylene, ionomer resin, polyurethane resin, ketone resin, ethylene-ethyl acrylate Examples thereof include a polymer, polybutyral, and a silicone resin. These can be used alone or in combination of two or more, and a polyester resin and a polyol resin are particularly preferable.
[0022]
Here, as the polyester resin, various types can be used.
(1) at least one selected from dihydric carboxylic acids and lower alkyl esters and acid anhydrides thereof;
(2) a diol component represented by the following general formula (I):
Embedded image

[0024]
(Wherein, R ¹ and R ² may be the same or different and each is an alkylene group having 2 to 4 carbon atoms, and x and y are the numbers of repeating units, each is 1 or more, and x + y = 2 to 16)
(3) at least one selected from the group consisting of trivalent or higher polycarboxylic acids, lower alkyl esters and acid anhydrides thereof, and trihydric or higher polyhydric alcohols; It is preferably a polyester resin obtained by a reaction.
[0025]
Here, examples of the divalent carboxylic acid (1) and its lower alkyl ester and acid anhydride include terephthalic acid, isophthalic acid, sebacic acid, isodecylsuccinic acid, maleic acid, fumaric acid, and monomethyl and monoethyl thereof. And dimethyl and diethyl esters, and phthalic anhydride and maleic anhydride, and terephthalic acid, isophthalic acid and dimethyl esters thereof are particularly preferred in terms of blocking resistance and cost. These divalent carboxylic acids and their lower alkyl esters and acid anhydrides greatly affect the fixability and blocking resistance of the toner. That is, depending on the degree of condensation, the use of a large amount of aromatic terephthalic acid, isophthalic acid or the like improves the blocking resistance but lowers the fixing property. Conversely, when sebacic acid, isodecylsuccinic acid, maleic acid, fumaric acid, etc. are used in a large amount, the fixing property is improved, but the blocking resistance is lowered. Therefore, these divalent carboxylic acids are appropriately selected according to other monomer compositions, ratios, and degrees of condensation, and used alone or in combination.
[0026]
Examples of the diol component represented by the general formula (I) of (2) include polyoxypropylene- (n) -polyoxyethylene- (n ')-2,2-bis (4-hydroxyphenyl) propane, Examples thereof include polyoxypropylene- (n) -2,2-bis (4-hydroxyphenyl) propane and polyoxyethylene- (n) -2,2-bis (4-hydroxyphenyl) propane. Polyoxypropylene- (n) -2,2-bis (4-hydroxyphenyl) propane where 1 ≦ n ≦ 2.5 and polyoxyethylene- (n)-where 2.0 ≦ n ≦ 2.5 2,2-bis (4-hydroxyphenyl) propane is preferred. Such a diol component has an advantage that the glass transition temperature is improved and the reaction is easily controlled.
[0027]
As the diol component, aliphatic diols such as ethylene glycol, diethylene glycol, 1,2-butanediol, 1,3-butanediol, 1,4-butanediol, neopentyl glycol, and propylene glycol can also be used. is there.
[0028]
Examples of (3) trivalent or higher polyvalent carboxylic acids and their lower alkyl esters and acid anhydrides include 1,2,4-benzenetricarboxylic acid (trimellitic acid) and 1,3,5-benzenetricarboxylic acid. 1,2,4-cyclohexanetricarboxylic acid, 2,5,7-naphthrenetricarboxylic acid, 1,2,4-naphthalenetricarboxylic acid, 1,2,4-butanetricarboxylic acid, 1,2,5-hexatricarboxylic acid Acid, 1,3-dicarboxyl-2-methyl-2-methylenecarboxypropane, tetra (methylenecarboxy) methane, 1,2,7,8-octanetetracarboxylic acid, empoletrimer acid and monomethyl, monoethyl thereof , Dimethyl and diethyl esters.
[0029]
Examples of (3) trihydric or higher polyhydric alcohols include sorbitol, 1,2,3,6-hexanetetrol, 1,4-sorbitan, pentaerythritol, dipentaerythritol, tripentaerythritol, Sugar, 1,2,4-butanetriol, 1,2,5-pentatriol, glycerol, diglycerol, 2-methylpropanetriol, 2-methyl-1,2,4-butanetriol, trimethylolethane, trimethylol And propane and 1,3,5-trihydroxymethylbenzene.
[0030]
Here, the compounding ratio of the trivalent or higher polyvalent monomer is suitably about 1 to 30 mol% of the whole monomer composition. When the amount is less than 1 mol%, the offset resistance of the toner tends to decrease, and the durability tends to deteriorate. On the other hand, when the content is 30 mol% or more, the fixability of the toner tends to deteriorate.
[0031]
Among these trivalent or higher polyvalent monomers, benzenetricarboxylic acids such as benzenetricarboxylic acid and anhydrides or esters of these acids are particularly preferred. That is, by using benzenetricarboxylic acids, it is possible to achieve both fixability and offset resistance.
[0032]
Various types of polyol resins can be used. In particular, (1) an epoxy resin, (2) an alkylene oxide adduct of a dihydric phenol or its glycidyl ether, and (3) a reaction with an epoxy group It is preferable to use a polyol resin obtained by reacting a compound having one active hydrogen in the molecule with a compound having two or more active hydrogens reacting with the epoxy group in the molecule.
[0033]
Here, the epoxy resin (1) is preferably obtained by combining bisphenol such as bisphenol A or bisphenol F with epichlorohydrin. In particular, the epoxy resin is at least two or more bisphenol A type epoxy resins having different number average molecular weights in order to obtain stable fixing characteristics and gloss, and the number average molecular weight of the low molecular weight component is 360 to 2000, and the high molecular weight component is Has a number average molecular weight of 3,000 to 10,000. Further, the low molecular weight component is preferably 20 to 50% by weight, and the high molecular weight component is preferably 5 to 40% by weight. If the low molecular weight component is too large, or if the molecular weight is lower than 360, gloss may be too high and storage stability may be deteriorated. Further, when the amount of the high molecular weight component is too large, or when the molecular weight is higher than 10,000, the gloss may be insufficient and the fixability may be deteriorated.
[0034]
Examples of the alkylene oxide adduct of dihydric phenol as the compound (2) include the following. That is, a reaction product of ethylene oxide, propylene oxide, butylene oxide, and a mixture thereof with a bisphenol such as bisphenol A or bisphenol F can be used. The obtained adduct may be glycidylated with epichlorohydrin, β-methylepichlorohydrin or the like before use. Particularly, a diglycidyl ether of an alkylene oxide adduct of bisphenol A represented by the following formula (II) is preferable.
[0035]
Embedded image

[0036]
(Wherein, R _{-CH 2 -CH 2 -, - CH} 2 -CH (CH 3) - or _-CH 2 _-CH 2 -CH ₂ - group wherein also n, m is the number of repeating units , Each being 1 or more, and n + m = 2 to 6.)
[0037]
Further, it is preferable that an alkylene oxide adduct of dihydric phenol or its glycidyl ether is contained in an amount of 10 to 40% by weight based on the polyol resin. Here, if the amount is small, a problem such as an increase in curl may occur, and if n + m is 7 or more or the amount is too large, gloss may be excessively obtained, and furthermore, storage stability may be deteriorated.
[0038]
Compounds having one active hydrogen in the molecule that reacts with the epoxy group of (3) include monohydric phenols, secondary amines and carboxylic acids. The following are examples of the monohydric phenols. That is, phenol, cresol, isopropylphenol, aminophenol, nonylphenol, dodecylphenol, xylenol, p-cumylphenol and the like can be mentioned. Secondary amines include diethylamine, dipropylamine, dibutylamine, N-methyl (ethyl) piperazine, piperidine and the like. Examples of the carboxylic acids include propionic acid and caproic acid.
[0039]
Examples of the compound having two or more active hydrogens in the molecule that react with the epoxy group in (4) include dihydric phenols, polyhydric phenols, and polyhydric carboxylic acids. Examples of the dihydric phenols include bisphenols such as bisphenol A and bisphenol F. Examples of the polyhydric phenols include orthocresol novolaks, phenol novolaks, tris (4-hydroxyphenyl) methane, and 1- [α-methyl-α- (4-hydroxyphenyl) ethyl] benzene. Examples of the polycarboxylic acids include malonic acid, succinic acid, glutaric acid, adipic acid, maleic acid, fumaric acid, phthalic acid, terephthalic acid, trimellitic acid, and trimellitic anhydride.
[0040]
In addition, when these polyester resins and polyol resins have a high crosslinking density, it is difficult to obtain transparency and glossiness. Therefore, they are preferably non-crosslinked or weakly crosslinked (THF insoluble content is 5% or less). Is preferred.
The method for producing these binder resins is not particularly limited, and any of bulk polymerization, solution polymerization, emulsion polymerization, suspension polymerization and the like can be used.
[0041]
Next, conventionally known dyes and pigments can be used as the colorant used in the toner.
Examples of yellow colorants include naphthol yellow S, Hansa yellow (10G, 5G, G), cadmium yellow, yellow iron oxide, loess, graphite, titanium yellow, polyazo yellow, oil yellow, Hansa yellow, (GR, A, RN, R), Pigment Yellow L, Benzidine Yellow (G, GR), Permanent Yellow (NCG), Vulcan Fast Yellow (5G, R), Tartrazine Lake, Quinoline Yellow Lake, Anthrazan Yellow BGL, And benzimidazolone yellow and isoindolinone yellow.
[0042]
Examples of the red colorant include red, red lead, red lead, cadmium red, cadmium mercury red, antimony red, permanent red 4R, para red, fire red, para chloro ortho nitroaniline red, and lithol fast scarlet. G, brilliant fast scarlet, brilliant carmine BS, permanent red (F2R, F4R, FRL, FRLL, F4RH), fast scarlet VD, Belcan fast rubin B, brilliant scarlet G, lithor rubin GX, permanent red (F5R, FBB), brilliant carmine 6B, Pigment Scarlet 3B, Bordeaux 5B, Toluidine Maroon, Permanent Bordeaux F2K, Helio Bordeaux BL, Bordeaux 10B, Bon Marloo Light, Bon Maroon Media, Eosin Lake, Rhodamine Lake B, Rhodamine Lake Y, Alizarin Lake, Thioindigo Red B, Thioindigo Maroon, Oil Red, Quinacridone Red, Pyrazolone Red, Polyazo Red, Chrome Vermilion, Benzidine Orange, Perinone Orange, oil orange and the like.
[0043]
Examples of the blue colorant include cobalt blue, cerulean blue, alkali blue lake, peacock blue lake, Victoria blue lake, metal-free phthalocyanine blue, phthalocyanine blue, fast sky blue, indanthrene blue (RS, BC), and indigo. Ultramarine, navy blue, anthraquinone blue, fast violet B, methyl violet lake, cobalt violet, manganese violet, dioxane violet, anthraquinone violet, chrome green, zinc green, chromium oxide, pyridian, emerald green, pigment green B, naphthol green B, Green gold, acid green lake, malachite green lake, phthalocyanine green, anthraquinone green and the like.
[0044]
Examples of the black colorant include azine dyes such as carbon black, oil furnace black, channel black, lamp black, acetylene black, and aniline black, metal salt azo dyes, metal oxides, and composite metal oxides. .
Examples of other coloring agents include titania, zinc white, lithopone, nigrosine dye, iron black, and the like.
These colorants can be used alone or in combination of two or more kinds, and the content is usually 1 to 30 parts by weight, preferably 3 to 20 parts by weight based on 100 parts by weight of the binder resin.
[0045]
Further, other materials such as a charge control agent and a release agent can be added to the toner used in the present invention, if necessary.
Here, as the charge control agent, a conventionally known charge control agent can be used, and examples thereof include a nigrosine dye, a chromium-containing complex, and a quaternary ammonium salt, which are selected depending on the polarity of the toner particles. In particular, in the case of a color toner, a colorless or light color that does not affect the color tone of the toner is preferable, and examples thereof include a metal salt of salicylic acid or a metal salt of a salicylic acid derivative (Bontron E84, manufactured by Orient).
These charge control agents can be used alone or in combination of two or more kinds. The content is usually 0.5 to 8 parts by weight, preferably 1 to 5 parts by weight, based on 100 parts by weight of the binder resin. is there.
[0046]
Further, in order to improve the releasing property of the toner from the fixing member at the time of fixing, and to improve the fixing property of the toner, it is also possible to include a releasing agent in the toner.
Here, as the release agent, conventionally known ones can be used. For example, low-molecular-weight polyethylene, low-molecular-weight polyolefin wax such as low-molecular-weight polypropylene, synthetic hydrocarbon wax such as Fischer-Tropsch wax, beeswax, carnauba Natural waxes such as wax, candelilla wax, rice wax and montan wax; petroleum waxes such as paraffin wax and microcrystalline wax; higher fatty acids such as stearic acid, palmitic acid and myristic acid; metal salts of higher fatty acids; and higher fatty acids. Examples thereof include amides and various modified waxes thereof.
[0047]
These release agents can be used alone or in combination of two or more types. In particular, good release properties can be obtained by using carnauba wax.
The content of the release agent is usually 1 to 15 parts by weight, preferably 2 to 10 parts by weight, based on 100 parts by weight of the binder resin. When the amount is less than 1 part by weight, the effect of preventing offset is insufficient, and when the amount is more than 15 parts by weight, transferability, durability and the like are reduced.
[0048]
Further, the toner used in the present invention may contain a magnetic substance and be used as a magnetic toner.
Specific magnetic materials include iron oxides such as magnetite, hematite, and ferrite, metals such as cobalt and nickel, or these metals and aluminum, copper, lead, magnesium, tin, zinc, antimony, beryllium, bismuth, cadmium, Examples include alloys with metals such as calcium, manganese, selenium, titanium, tungsten, and vanadium, and mixtures thereof.
[0049]
These magnetic materials preferably have an average particle size of about 0.1 to 2 μm, and the content is usually 20 to 200 parts by weight, preferably 40 to 150 parts by weight, based on 100 parts by weight of the binder resin. .
[0050]
As the small particles used in the present invention, one or a plurality of resin particles can be selected and used according to the purpose. In particular, it is preferable to use the same resin as the base particles because the small particles have high adhesiveness. In consideration of fixability, heat resistance, and cohesion resistance, it is preferable to select a resin having a softening point higher than that of the base material.
[0051]
Specifically, as a raw material, a vinyl monomer, for example, styrene, o-methylstyrene, m-methylstyrene, p-methylstyrene, p-ethylstyrene, 2,4-dimethylstyrene, pn-butylstyrene Pt-butylstyrene, pn-hexylstyrene, pn-octylstyrene, pn-nonylstyrene, pn-decylstyrene, pn-dodecylstyrene, n-methoxystyrene, p- Styrene monofunctional monomers such as phenylstyrene, p-chlorostyrene, and 3,4-dichlorostyrene; ethylenically unsaturated monoolefins such as ethylene, propylene, butylene, and isobutylene; vinyl chloride, vinylidene chloride, and bromide Vinyl halides such as vinyl and vinyl fluoride, vinyl acetate, vinyl propionate, vinyl benzoate, vinyl butyrate Vinyl ester, methyl acrylate, ethyl acrylate, propyl acrylate, n-butyl acrylate, isobutyl acrylate, n-octyl acrylate, dodecyl acrylate, 2-ethylhexyl acrylate, stearyl acrylate, acrylic acid 2 -Chloroethyl, phenyl acrylate, α-methyl methacrylate, ethyl methacrylate, propyl methacrylate, n-butyl methacrylate, isobutyl methacrylate, n-octyl methacrylate, dodecyl methacrylate, 2-ethylhexyl methacrylate, methacrylic acid Α-methylene aliphatic monocarboxylic esters such as stearyl, phenyl methacrylate, dimethylaminoethyl acrylate, diethylaminoethyl methacrylate, acrylonitrile, methacrylonitrile, acrylic Amide, methacrylamide and the like are used, and in some cases, unsaturated carboxylic acids such as acrylic acid, methacrylic acid, maleic acid and fumaric acid, vinyl ethers such as vinyl methyl ether, vinyl ethyl ether and vinyl isobutyl ether, and acrylic acid 2- Acrylic acid or methacrylic acid derivatives such as hydroxyethyl, 2-hydroxyethyl methacrylate and 2-hydroxypropyl methacrylate; vinyl ketones such as vinyl methyl ketone, vinyl hexyl ketone and methyl isopropenyl ketone; N-vinyl pyrrole; N-vinyl N-vinyl compounds such as carbazole, N-vinylindole and N-vinylpyrrolidone; vinyl naphthalene salts; aromatic divinyl compounds such as divinylbenzene, divinylnaphthalene and derivatives thereof; Acrylate, ethylene glycol dimethacrylate, diethylene glycol dimethacrylate, triethylene glycol triacrylate, trimethylolpropane triacrylate, 1,6-hexanediol dimethacrylate, trimethylolpropane trimethacrylate, pentaerythritol tetramethacrylate, N, N-divinylaniline, Those produced from divinyl ether, divinyl sulfite and the like can be used. These are used by homopolymerization or copolymerization.
[0052]
Next, an example of a production example of the toner used in the present invention will be described below.
{Circle around (1)} The above-described binder resin, colorant, or, if necessary, a charge control agent, a release agent, a magnetic substance, and the like are sufficiently mixed by a mixer such as a Henschel mixer.
{Circle around (2)} Two-roll batch type, Banbury mixer and continuous twin-screw extruder, for example, KTK twin-screw extruder manufactured by Kobe Steel, TEM twin-screw extruder manufactured by Toshiba Machine Co., Ltd., twin-screw extruder manufactured by KCK Using an extruder, a PCM type twin screw extruder manufactured by Ikegai Iron Works, KEX type twin screw extruder manufactured by Kurimoto Iron Works, or a continuous single screw kneader, for example, a hot kneader such as a bus kneader co-kneader. Knead the constituent materials thoroughly.
(3) After cooling the kneaded material, coarsely pulverize it with a hammer mill or the like, further pulverize it with a fine pulverizer using a jet stream or a mechanical pulverizer, and use a classifier using a swirling stream and the Coanda effect. The particles are classified to a predetermined particle size by a classifier to obtain base particles.
[0053]
Further, as other production methods, a polymerization method, a capsule method, or the like can be used. The outline of these production methods is described below.
[0054]
(Polymerization method)
{Circle around (1)} A polymerizable monomer, and if necessary, a polymerization initiator and a colorant are granulated in an aqueous dispersion medium.
{Circle around (2)} The granulated monomer composition particles are classified into an appropriate particle diameter.
{Circle around (3)} The monomer composition particles having a specified internal particle diameter obtained by the above classification are polymerized.
{Circle around (4)} After removing the dispersant by performing an appropriate treatment, the polymerization product obtained above is filtered, washed with water and dried to obtain base particles.
[0055]
(Capsule method)
{Circle around (1)} A resin, a colorant and the like, if necessary, are kneaded with a kneader or the like to obtain a toner core material in a molten state.
{Circle around (2)} The toner core material is placed in water and stirred vigorously to form a fine particle core material.
{Circle around (3)} The core fine particles are placed in a shell material solution, and a poor solvent is dropped with stirring, and the core material is encapsulated by covering the surface with a shell material.
{Circle around (4)} The capsules obtained above are filtered and dried to obtain base particles.
[0056]
Then, the base particles and the additives were sufficiently mixed by a mixer such as a Henschel mixer (manufactured by Mitsui Miike), a mechanofusion system (manufactured by Hosokawa Micron), a mechanomill (manufactured by Okada Seiko Co., Ltd.), and if necessary, 150 μm. Aggregates and coarse particles are removed by passing through a sieve having a mesh size of less than about.
[0057]
Here, conventionally known additives can be used, for example, Si, Ti, Al, Mg, Ca, Sr, Ba, In, Ga, Ni, Mn, W, Fe, Co, Zn, Cr, Examples thereof include oxides such as Mo, Cu, Ag, V, and Zr, and composite oxides. In particular, silica, titania, and alumina, which are oxides of Si, Ti, and Al, are preferably used.
[0058]
The additive amount at this time is preferably 0.6 to 4.0 parts by weight, particularly preferably 1.0 to 3.6 parts by weight, based on 100 parts by weight of the base particles. is there.
When the amount of the additive is less than 0.6 parts by weight, the fluidity of the toner is reduced, so that sufficient chargeability cannot be obtained, and the transferability and heat-resistant storage stability also become insufficient, It is easy to cause soiling and toner scattering.
[0059]
When the amount is more than 4.0 parts by weight, although the fluidity is improved, the cleaning of the photoreceptor such as chattering and turning up of the blade and the filming of the photoreceptor by the additive released from the toner are liable to occur. And the durability of the photoconductor and the like, and the fixability also deteriorates.
[0060]
Here, there are various methods for measuring the content of the additive, but it is generally determined by X-ray fluorescence analysis. That is, a calibration curve is created by a fluorescent X-ray analysis method for a toner having a known content of the additive, and the content of the additive can be determined using the calibration curve.
Further, it is preferable that the additive has been subjected to a surface treatment, if necessary, for the purpose of hydrophobization, improvement of fluidity, control of chargeability, and the like.
[0061]
Here, as the treating agent used for the surface treatment, an organic silane compound or the like is preferable, for example, alkyltrichlorosilanes such as methyltrichlorosilane, octyltrichlorosilane, and dimethyldichlorosilane; and alkyl such as dimethyldimethoxysilane and octyltrimethoxysilane. Examples include methoxysilanes, hexamethyldisilazane, silicone oil and the like.
[0062]
Examples of the treatment method include a method in which an additive is immersed and dried in a solution containing an organic silane compound, and a method in which a solution containing an organic silane compound is sprayed and dried in an additive. Any method can be suitably used.
[0063]
Further, the particle size of the additive added to the base particles is preferably 0.002 to 0.2 μm in terms of average primary particle size, particularly preferably 0.005 to 0, from the viewpoint of imparting fluidity. 0.05 μm.
[0064]
Additives having an average primary particle diameter of less than 0.002 μm are liable to be buried in the surface of the base particles, so that aggregation is likely to occur and sufficient fluidity cannot be obtained. Further, filming on a photoreceptor or the like is apt to occur, and these tendencies are particularly remarkable under high temperature and high humidity. In addition, when the average primary particle diameter is smaller than 0.002 μm, the additives are liable to agglomerate inevitably, which also makes it difficult to obtain sufficient fluidity.
[0065]
Further, an additive having an average primary particle size of more than 0.2 μm reduces the fluidity of the toner, so that sufficient chargeability cannot be obtained, and this tends to cause background stain and toner scattering. Additives having an average primary particle size of more than 0.1 μm are apt to damage the surface of the photoreceptor and cause filming or the like.
The particle size of the additive can be determined by measuring with a transmission electron microscope.
[0066]
In addition to the above additives, other additives can be added to the toner used in the present invention. Examples of such additives include Teflon (registered trademark), zinc stearate, and polyvinylidene fluoride as lubricants, and cerium oxide, silicon carbide, and strontium titanate as abrasives, and a conductivity-imparting material. Examples thereof include zinc oxide, antimony oxide, and tin oxide.
[0067]
Further, the particle diameter of the toner used in the present invention is preferably 4 to 9 μm in weight average diameter, and particularly preferably 5 to 8 μm.
If the particle diameter is smaller than 4 μm, background contamination or toner scattering may occur at the time of development, or the fluidity may be deteriorated, and toner replenishment or cleaning performance may be impaired. Further, when the particle size is larger than 8 μm, dust in the image and deterioration of resolution may become a problem. Particularly, in the case of a color image, the influence is large.
[0068]
The toner used in the present invention is applicable to both one-component toner and two-component toner. In the case of a two-component toner, it is mixed with a carrier and used as a two-component developer.
Here, as the carrier, conventionally known carriers can be used, and examples thereof include powder having magnetic properties such as iron powder, ferrite powder, and nickel powder, and glass beads. It is preferable to coat with.
[0069]
In this case, examples of the resin used include polyfluorocarbon, polyvinyl chloride, polyvinylidene chloride, phenol resin, polyvinyl acetal, acrylic resin, and silicone resin.
As a method for forming the resin layer, a resin may be applied to the surface of the carrier by a spraying method, a dipping method, or the like, as in the related art.
The amount of the resin used is preferably 1 to 10 parts by weight based on 100 parts by weight of the carrier.
[0070]
Further, the thickness of the resin is preferably 0.02 to 2 μm, particularly preferably 0.05 to 1 μm, and more preferably 0.1 to 0.6 μm. The fluidity of the developer tends to decrease, and when the film thickness is small, the film tends to be easily affected by abrasion over time.
Here, the average particle size of these carriers is usually 10 to 100 μm, preferably 30 to 60 μm.
[0071]
Further, the mixing ratio of the toner and the carrier is generally suitable for the toner to be about 0.5 to 7.0 parts by weight with respect to 100 parts by weight of the carrier.
[0072]
(Roundness)
The shape factors SF-1 and SF-2, which are the degrees of circularity used in the present invention, are obtained by randomly sampling 300 SEM images of toner obtained by measuring with FE-SEM (S-4200) manufactured by Hitachi, Ltd. Then, the image information was introduced into an image analysis device (Luzex AP) manufactured by Nireco via an interface, analyzed, and the values calculated by the following equations were defined as SF-1 and SF-2. The values of SF-1 and SF-2 are preferably values obtained by Luzex, but are not particularly limited to the above-mentioned FE-SEM apparatus and image analysis apparatus as long as similar analysis results can be obtained.
[0073]
SF-1 = (L ² / A) × (π / 4) × 100
SF-2 = (P ² / A) × (1 / 4π) × 100
here,
The absolute maximum length of the toner is L
The projected area of toner is A
Maximum toner circumference is P
And If the sphere is a true sphere, it becomes 100, and as the value becomes larger than 100, the shape changes from a sphere to an irregular shape. In particular, SF-1 represents the shape of the entire toner (such as an ellipse or a sphere), and SF-2 is a shape coefficient indicating the degree of surface irregularities.
[0074]
<Example of toner production>
Example 1

The above raw materials were mixed with a Henschel mixer to obtain a mixture in which water was permeated into the pigment aggregate. This was kneaded with two rolls set at a roll surface temperature of 128 ° C. for 45 minutes, rolled and cooled, and pulverized with a pulperizer to obtain a master batch colorant.
[0075]

After mixing the above materials with a mixer, the mixture was melt-kneaded five times with a two-roll mill, and the kneaded product was rolled and cooled. Thereafter, an impingement plate type pulverizer (type I mill; manufactured by Nippon Pneumatic Industries, Ltd.) using a jet mill and a wind classifier (DS classifier; manufactured by Nippon Pneumatics Co., Ltd.) using a swirling flow were used to obtain a volume average particle size of 5.5 μm. Thus, magenta toner base particles A having a number average particle size of 4.5 μm were obtained.
[0076]
(Example of production of small particles) 95 parts of ion-exchanged water is charged into a flask equipped with a stirrer, a dropping funnel, a nitrogen introducing agent, a cooling agent and a thermometer, and after the temperature is increased and the nitrogen is replaced, the temperature is maintained at 65 ° C. The mixture was stirred at a rotation speed of 200 rpm, and a mixture of 40 parts of styrene and 20 parts of n-butyl acrylate was added dropwise over 4 hours. Further, 0.14 part of potassium persulfate dissolved in 5 parts of ion-exchanged water was added over 6 hours. After heating for 11 hours, the mixture was heated at 80 ° C. for 3 hours to complete the polymerization. The obtained fine particles were dispersed in a 90 ° C. saturated solution of Bontron E84 in a flask, and the whole solution was rapidly cooled to 30 ° C. to precipitate Bontron E84 on the surface of the resin particles, thereby obtaining small particles B.
[0077]
At this time, the conversion was 97%, and the particle size was 0.42 μm. The glass transition point of the dried particles was 70 ° C. For drying, the polymerization solution was frozen and dried under reduced pressure. 97 parts of the base particles A and 3 parts of the small particles B were treated with a hybridization system [Nara Machinery Co., Ltd. NHS-O] at 12,000 rpm for 2 minutes to perform immobilization, thereby preparing toner C. The coverage of the surface of the base particles with the small particles was about 90% by observation with an electron microscope.
[0078]
Example 2
The toner production method was changed to the following emulsion polymerization method.
First, as a resin dispersion 1,
Styrene 350 parts Butyl acrylate 41 parts Acrylic acid 9 parts Dodecyl mercaptan 16 parts Carbon tetrabromide 5 parts (all are manufactured by Wako Pure Chemical Industries, Ltd.)
[0079]
9 parts of a nonionic surfactant (Noniball 85, manufactured by Sanyo Kasei Co., Ltd.) and 11 parts of anionic surfactant (Neogen SC, manufactured by Daiichi Kogyo Seiyaku Co., Ltd.) were added to 582 parts of ion-exchanged water. While dissolving, dispersing and emulsifying in a flask, and slowly mixing for 15 minutes, 50 g of ion-exchanged water in which 3.4 g of ammonium persulfate (manufactured by Tokai Denka Co., Ltd.) was dissolved, and nitrogen replacement was performed. Thereafter, the contents were heated to 73 ° C. in an oil bath while stirring the flask, emulsion polymerization was continued for 7 hours, and then cooled to room temperature to obtain a resin dispersion. From the obtained resin dispersion, the solvent was left on an oven at 80 ° C. to remove water. A resin dispersion liquid 1 having a center particle diameter of 120 nm, a glass transition point of 55 ° C., and Mw of 22,000 was obtained.
[0080]
Pigment Red 122, 70 parts was added to and mixed with 300 parts of ion-exchanged water together with 2 parts of an anionic surfactant (manufactured by Sanyo Kasei Co., Ltd., Ionnet D-2), and dispersed with IKA Ultra Turrax T50. A pigment dispersion 1 having a center diameter of 160 nm was obtained.
50 parts of a wax (fatty acid ester wax, melting point: 83 ° C., viscosity: 280 mPa · s (90 ° C.)) were added to 300 parts of ion-exchanged water together with 2 parts of an anionic surfactant (manufactured by Sanyo Chemical Co., Ltd., Ionette D-2). Then, the mixture was subjected to dispersion treatment with IKA Ultra Turrax T50 to obtain a wax dispersion liquid 1.
[0081]
Next, the above-mentioned resin dispersion 1, pigment dispersion 1, and wax dispersion 1 were mixed at the following ratios,
Deionized water 300 parts Resin dispersion 1 240 parts Pigment dispersion 1 40 parts Wax dispersion 1 35 parts Cationic surfactant 2 parts (Sanisol B50, manufactured by Kao Corporation)
[0082]
After mixing and dispersing in a round stainless steel flask with Ultra Turrax T50, the flask was heated to 48 ° C. while stirring the flask in an oil bath for heating. After maintaining at 48 ° C. for 4 hours, observation with an optical microscope confirmed that aggregated particles of about 5.5 μm had been formed. Thereafter, 6 parts of Neogen SC was additionally added, and the mixture was heated to 93 ° C. while continuing stirring and maintained for 9 hours. Thereafter, the flask was cooled to room temperature at a rate of 10 ° C./min, further filtered, washed sufficiently with ion-exchanged water, and kept in a vacuum dryer at 50 ° C. for 12 hours, the volume average particle diameter was 5.5 μm, and the number average Magenta toner base particles D having a particle size of 4.7 μm and a molecular weight Mw of 22,000 were obtained.
97 parts of the base particles D and 3 parts of the small particles B were treated with a hybridization system [Nara Machinery Co., Ltd. NHS-O] at 12,000 rpm for 2 minutes to perform immobilization, thereby preparing a toner E. The circularity SF-1 of the toner was 108 and SF-2 was 105.
[0083]
<Example of carrier production>

[0084]
The coating material is dispersed by a stirrer for 10 minutes to prepare a coating solution, and the coating solution and the core material are applied to a coating apparatus for performing coating while forming a swirling flow provided with a rotating bottom plate disk and a stirring blade in a fluidized bed. Then, the coating solution was applied onto the core material.
Further, the obtained carrier was calcined in an electric furnace at 250 ° C. for 2 hours to obtain a carrier (film thickness: 0.5 μm) of a production example.
[0085]
The charge amount of the small particles B with respect to the carrier is −30 μC / g when the toner concentration is 5.0 wt%, and the charge amount of the base toner particles D with respect to the carrier is −25 μC / g when the small particle concentration is 5.0 wt%. And q1 / q2 = 1.20.
The charge amount of the base toner particles D with respect to the carrier was −20 μC / g when the small particle concentration was 5.0 wt%, and q1 / q2 = 1.50.
[0086]
<Production example of developer>
5 parts of the toner of the above-mentioned Production Example and additives were mixed with 95 parts of the carrier of the above-mentioned Production Example by a turbuler mixer to obtain a developer.
[0087]
ImagioMF1340 manufactured by Ricoh Co., Ltd., which uses the following printer for evaluation, was used. Used at a toner concentration of 6%.
Printing was performed on 10,000 sheets using the developer and toner manufactured in the manufacturing example.
The background smear of the printed image during that time and the degree of toner scattering inside the printer after 10,000 sheets were completed were evaluated.
[0088]
All of the toners of the present invention formed good images. The density difference between the background density of 10,000 sheets and the initial density was within 0.02 as measured by X-RITE.
Also, toner scattering inside the printer after 10,000 sheets was hardly observed. Even when photographic images having a large image area were continuously used as print images, no background stain was observed on the obtained images.

Claims (10)

An electrophotographic toner having small particles uniformly adhered to the surface of the base particles, and having a charge characteristic for the carrier of small particle charge amount = q1 and base particle charge amount = q2,
0.95 <q1 / q2 <1.60
A dry type electrophotographic toner, characterized in that: 2. The dry electrophotographic toner according to claim 1, wherein a charge controlling agent is dispersed in the small particles. 3. The dry electrophotographic toner according to claim 1, wherein a polarity controlling agent is attached to the surface of the small particles. 4. The dry electrophotographic toner according to claim 3, wherein a water-soluble compound is used as the charge control agent. 5. The charge control agent according to claim 3, wherein the toner or the small particles are dispersed in a supersaturated solution of the charge control agent, and the solution is cooled to precipitate the charge control agent, and the charge control agent is attached to the surface of the small particles. Dry electrophotographic toner. The dry electrophotographic toner according to any one of claims 1 to 5, wherein the mother particle surface coverage of the small particles is 80% or more. The dry electrophotographic toner according to any one of claims 1 to 6, wherein the average particle size of the small particles is 0.1 to 0.8 µm. The toner according to claim 1, wherein the base particles are obtained by polymerization, and the toner particles after adhesion of the small particles have a circularity SF-1 value of 100 to 140 and a circularity SF-2 value of 100 to 130. Item 7. A dry electrophotographic toner according to Item 1. The toner or small particles are dispersed in a supersaturated solution of the charge control agent, and the charge control agent is precipitated by cooling the solution, and the charge control agent is attached to the surface of the small particles. Production method of toner. An image forming method using the toner according to claim 1.