JP4093883B2 - Toner for electrostatic image development, developer and image forming apparatus - Google Patents

Description

【００７２】
また、本発明のトナーにおいては、アミノ基以外にも、例えば、界面活性剤等に含まれている洗浄しきれなかったＮａなどのカチオンも同時にＣＰＲの値として測定されるが、これらも正帯電性を示すことから、トナー中の正帯電成分として存在することとなり、カブリ発生の原因となることから、ＣＰＲを３００以下にすることが必須の条件である。
【００７３】
本発明において、ＣＰＲ３００以下を達成するためには、以下の方法が挙げられる。反応基（イソシアネート基を有するプレポリマー（Ａ）のイソシアネート基とアミン類（Ｂ）のアミノ基）の混合比率、反応温度、反応時間を調整することにより、反応を完結させ、ＮＨ₃ ⁺等のカチオンとして存在しうる未反応のアミノ基（Ｂ）の残存率を少なくすること、及びＮａ⁺などのカチオンとして存在しうる活性剤等の処理量、洗浄条件等で残存物を少なくすることが重要である。特に、イソシアネート基とアミノ基の比率が重要な因子であり、１００：９６〜１００：８０が好ましく、１００：９６〜１００：９０が更に好ましい。イソシアネート基含有率は、ＪＩＳ Ｋ ７３０１に記載されている方法により求めることができる。アミノ基含有率は、ＪＩＳ Ｋ ７２４５に記載されている方法により求めることができる。
【００７４】
（二成分用キャリア）
本発明のトナーを二成分系現像剤に用いる場合には、磁性キャリアと混合して用いれば良く、現像剤中のキャリアとトナーの含有比は、キャリア１００重量部に対してトナー１〜１０重量部が好ましい。磁性キャリアとしては、粒子径２０〜２００μｍ程度の鉄粉、フェライト粉、マグネタイト粉、磁性樹脂キャリアなど従来公知のものが使用できる。また、被覆材料としては、アミノ系樹脂、例えば尿素−ホルムアルデヒド樹脂、メラミン樹脂、ベンゾグアナミン樹脂、ユリア樹脂、ポリアミド樹脂、エポキシ樹脂等が挙げられる。またポリビニル及びポリビニリデン系樹脂、例えばアクリル樹脂、ポリメチルメタクリレート樹脂、ポリアクリロニトリル樹脂、ポリ酢酸ビニル樹脂、ポリビニルアルコール樹脂、ポリビニルブチラール樹脂、ポリスチレン樹脂及びスチレンアクリル共重合樹脂等のポリスチレン系樹脂、ポリ塩化ビニル等のハロゲン化オレフィン樹脂、ポリエチレンテレフタレート樹脂及びポリブチレンテレフタレート樹脂等のポリエステル系樹脂、ポリカーボネート系樹脂、ポリエチレン樹脂、ポリ弗化ビニル樹脂、ポリ弗化ビニリデン樹脂、ポリトリフルオロエチレン樹脂、ポリヘキサフルオロプロピレン樹脂、弗化ビニリデンとアクリル単量体との共重合体、弗化ビニリデンと弗化ビニルとの共重合体、テトラフルオロエチレンと弗化ビニリデンと非弗化単量体とのターポリマー等のフルオロターポリマー、及びシリコーン樹脂等が使用できる。また必要に応じて、導電粉等を被覆樹脂中に含有させてもよい。導電粉としては、金属粉、カーボンブラック、酸化チタン、酸化錫、酸化亜鉛等が使用できる。これらの導電粉は、平均粒子径１μｍ以下のものが好ましい。平均粒子径が１μｍよりも大きくなると、電気抵抗の制御が困難になる。
【００７５】
また、本発明のトナーはキャリアを使用しない一成分系の磁性トナー或いは、非磁性トナーとしても用いることができる。
【００７６】
次に、本発明において好適に用いられるトナーの形状について説明する。本発明のトナーは、図１に示すような紡錘形状であることが好ましい。
トナー形状が一定しない不定形、又は扁平形状では粉体流動性が悪いことから、次のような課題を持つ。摩擦帯電が円滑に行えないことから地肌汚れ等の問題が発生しやすい。微小な潜像ドットを現像する際には、緻密で均一なトナー配置をとりにくいことから、ドット再現性に劣る。静電転写方式では、電気力線の影響を受けにくく、転写効率が劣る。
トナーが真球に近い場合、粉体流動性が良すぎて、外力に対して過度に作用してしまうことから、現像及び転写の際に、ドットの外側にトナー粒子が飛び散りやすいといった問題がある。また、球形トナーでは、感光体上で転がりやすいことために、感光体とクリーニング部材との間に潜り込みクリーニング不良となることが多いという問題点がある。
【００７７】
本発明の紡錘形状のトナーは、粉体流動性が適度に調節されているために、摩擦帯電が円滑に行われて地肌汚れを発生させることがなく、微小な潜像ドットに対して整然と現像され、その後、効率よく転写されてドット再現性に優れる。更に、その際の飛び散りに対しては、粉体流動性が適度にブレーキをかけて飛び散りを防いでいる。紡錘形状のトナーは球形トナーに比べて、転がる軸が限られていることから、クリーニング部材の下に潜り込むようなクリーニング不良が発生しにくい。
【００７８】
本発明のトナーは、長軸と短軸との比（ｒ２／ｒ１）が０．５〜０．８で、厚さと短軸との比（ｒ３／ｒ２）が０．７〜１．０で表される紡錘形状であることがより好ましい。長軸と短軸との比（ｒ２／ｒ１）が０．５未満では、真球形状から離れるためにクリーニング性が高いが、ドット再現性及び転写効率が劣るために高品位な画質が得られなくなる。長軸と短軸との比（ｒ２／ｒ１）が０．８を越えると、球形に近づくために、低温低湿の環境下では特にクリーニング不良が発生することがある。また、厚さと短軸との比（ｒ３／ｒ２）が０．７未満では、扁平形状に近く、不定形トナーのように飛び散りは少ないが、球形トナーのような高転写率は得られない。特に、厚さと短軸との比（ｒ３／ｒ２）が１．０では、長軸を回転軸とする回転体となる。これに近い紡錘状形状にすることで不定形・扁平形状でもなく真球状でもない形状であって、双方の形状が有する摩擦帯電性、ドット再現性、転写効率、飛び散りの防止性、クリーニング性の全てを満足させる形状となる。
なお、ｒ１、ｒ２、ｒ３は、走査型電子顕微鏡（ＳＥＭ）で、視野の角度を変えて写真を撮り、観察しながら測定した。
【００７９】
図２に本発明の画像形成装置における定着装置の一例の概略図を示す。この図において、１は定着ローラ、２は加圧ローラ、３は金属シリンダー、４はオフセット防止層、５は加熱ランプ、６は金属シリンダー、７はオフセット防止層、８は加熱ランプ、Ｔはトナー像、Ｓは支持体（紙等の転写紙）を示す。本発明においては、２本のローラ間に加わる面圧（ローラ荷重／接触面積）を１．５×１０^５Ｐａ以下で定着を行うことができる。
【００８０】
上記定着装置において、２本のローラ間に加わる面圧（ローラ荷重／接触面積）を１．５×１０^５Ｐａ以下で定着することは従来はなかった。従来の面圧は１．５×１０^５Ｐａを越えており、そうでないと、十分に定着することができなかった。これに対し、本発明のトナーは低温でも定着できるものであり、面圧が１．５×１０^５Ｐａ以下という低面圧でも定着することが可能になる。また、低面圧にしたことで、転写媒体上のトナー画像を押しつぶし乱さないので、高精細な画像出力が可能となる。
【００８１】
また、定着装置は、図３に示すように、定着フィルムを回転させて定着する、いわゆるサーフ定着装置を用いることもできる。以下詳説すると、定着フィルムはエンドレスベルト状耐熱フィルムであり、該フィルムの支持回転体である駆動ローラと、従動ローラと、この両ローラ間の下方に設けたヒータ支持体に保持させて固定支持させて配設した加熱体と、に懸回張設してある。
【００８２】
従動ローラは定着フィルムのテンションローラを兼ね、定着フィルムは駆動ローラの図中時計回転方向の回転駆動によって、時計回転方向に向かって回転駆動される。この回転駆動速度は、加圧ローラと定着フィルムが接する定着ニップ領域Ｌにおいて転写材と定着フィルムの速度が等しくなる速度に調節される。
ここで、加圧ローラはシリコンゴム等の離型性のよいゴム弾性層を有するローラであり、反時計周りに回転しつつ、前記定着ニップ領域Ｌに対して総圧４〜１０ｋｇの当接圧をもって圧接させてある。
【００８３】
また定着フィルムは、耐熱性、離型性、耐久性に優れたものが好ましく、総厚１００μｍ以下、好ましくは４０μｍ以下の薄肉のものを使用する。例えばポリイミド、ポリエーテルイミド、ＰＥＳ（ポリエーテルサルファイド）、ＰＦＡ（四フッ化エチレンバーフルオロアルキルビニルエーテル共重合体樹脂）等の耐熱樹脂の単層フィルム、或いは複合層フィルム、例えば２０μｍ厚フィルムの少なくとも画像当接面側にＰＴＦＥ（四フッ化エチレン樹脂）、ＰＦＡ等のフッ素樹脂に導電材を添加した離型性コート層を１０μｍ厚に施したものや、フッ素ゴム、シリコンゴム等の弾性層を施したものである。
【００８４】
図３において本実施形態の加熱体は平面基板および定着ヒータから構成されており、平面基板は、アルミナ等の高熱伝導度且つ高電気抵抗率を有する材料からなっており、定着フィルムと接触する表面には抵抗発熱体で構成した定着ヒータを長手方向に設置してある。かかる定着ヒータは、例えばＡｇ/Ｐｄ、Ｔａ₂Ｎ等の電気抵抗材料をスクリーン印刷等により線状もしくは帯状に塗工したものである。また、前記定着ヒータの両端部には、図示しない電極が形成され、この電極間に通電することで抵抗発熱体が発熱する。さらに、前記基板の定着ヒータが具備させてある面と逆の面にはサーミスタによって構成した定着温度センサが設けられている。
定着温度センサによって検出された基板の温度情報は図示しない制御手段に送られ、かかる制御手段により定着ヒータに供給される電力量が制御され、加熱体は所定の温度に制御される。
このような定着装置を用いることにより、効率よく立ち上がり時間を短縮可能にすることができる。
【００８５】
本発明の画像形成装置に用いられる電子写真用感光体としては、導電性支持体を５０℃〜４００℃に加熱し、該支持体上に真空蒸着法、スパッタリング法、イオンプレーティング法、熱ＣＶＤ法、光ＣＶＤ法、プラズマＣＶＤ法等の成膜法によりａ−Ｓｉからなる光導電層を有するアモルファスシリコン感光体（以下、「ａ−Ｓｉ系感光体」と称する。）を用いることができる。なかでもプラズマＣＶＤ法、すなわち、原料ガスを直流または高周波あるいはマイクロ波グロー放電によって分解し、支持体上にａ−Ｓｉ堆積膜を形成する方法が好適なものとして用いられている。
【００８６】
アモルファスシリコン感光体の層構成は例えば以下のようなものである。図４は、層構成を説明するための模式的構成図である。図４（ａ）に示す電子写真用感光体５００は、支持体５０１の上にａ−Ｓｉ：Ｈ、Ｘ（Ｘはハロゲン元素を表す）からなり光導電性を有する光導電層５０２が設けられている。図４（ｂ）に示す電子写真用感光体５００は、支持体５０１の上に、ａ−Ｓｉ：Ｈ、Ｘからなり光導電性を有する光導電層５０２と、アモルファスシリコン系表面層５０３とから構成されている。図４（ｃ）に示す電子写真用感光体５００は、支持体５０１の上に、ａ−Ｓｉ：Ｈ、Ｘからなり光導電性を有する光導電層５０２と、アモルファスシリコン系表面層５０３と、アモルファスシリコン系電荷注入阻止層５０４とから構成されている。図４（ｄ）に示す電子写真用感光体５００は、支持体５０１の上に、光導電層５０２が設けられている。該光導電層５０２はａ−Ｓｉ：Ｈ、Ｘからなる電荷発生層５０５ならびに電荷輸送層５０６とからなり、その上にアモルファスシリコン系表面層５０３が設けられている。
【００８７】
感光体の支持体としては、導電性でも電気絶縁性であってもよい。導電性支持体としては、Ａｌ、Ｃｒ、Ｍｏ、Ａｕ、Ｉｎ、Ｎｂ、Ｔｅ、Ｖ、Ｔｉ、Ｐｔ、Ｐｄ、Ｆｅ等の金属、およびこれらの合金、例えばステンレス等が挙げられる。また、ポリエステル、ポリエチレン、ポリカーボネート、セルロースアセテート、ポリプロピレン、ポリ塩化ビニル、ポリスチレン、ポリアミド等の合成樹脂のフィルムまたはシート、ガラス、セラミック等の電気絶縁性支持体の少なくとも感光層を形成する側の表面を導電処理した支持体も用いることができる。
支持体の形状は平滑表面あるいは凹凸表面の円筒状または板状、無端ベルト状であることができ、その厚さは、所望通りの画像形成装置用感光体を形成し得るように適宜決定するが、画像形成装置用感光体としての可撓性が要求される場合には、支持体としての機能が充分発揮できる範囲内で可能な限り薄くすることができる。しかしながら、支持体は製造上および取り扱い上、機械的強度等の点から通常は１０μｍ以上とされる。
【００８８】
本発明に用いることができるアモルファスシリコン感光体には必要に応じて導電性支持体と光導電層との間に、導電性支持体側からの電荷の注入を阻止する働きのある電荷注入阻止層を設けるのがいっそう効果的である（図４（ｃ））。すなわち、電荷注入阻止層は感光層が一定極性の帯電処理をその自由表面に受けた際、支持体側より光導電層側に電荷が注入されるのを阻止する機能を有し、逆の極性の帯電処理を受けた際にはそのような機能が発揮されない、いわゆる極性依存性を有している。そのような機能を付与するために、電荷注入阻止層には伝導性を制御する原子を光導電層に比べ比較的多く含有させる。
電荷注入阻止層の層厚は所望の電子写真特性が得られること、及び経済的効果等の点から好ましくは０．１〜５μｍ、より好ましくは０．３〜４μｍ、最適には０．５〜３μｍとされるのが望ましい。
【００８９】
光導電層は必要に応じて下引き層上に形成され、光導電層の層厚は所望の電子写真特性が得られること及び経済的効果等の点から適宜所望にしたがって決定され、好ましくは１〜１００μｍ、より好ましくは２０〜５０μｍ、最適には２３〜４５μｍとされるのが望ましい。
【００９０】
電荷輸送層は、光導電層を機能分離した場合の電荷を輸送する機能を主として奏する層である。この電荷輸送層は、その構成要素として少なくともシリコン原子と炭素原子と弗素原子とを含み、必要であれば水素原子、酸素原子を含むａ−ＳｉＣ（Ｈ、Ｆ、Ｏ）からなり、所望の光導電特性、特に電荷保持特性、電荷発生特性および電荷輸送特性を有する。本発明においては酸素原子を含有することが特に好ましい。
電荷輸送層の層厚は所望の電子写真特性が得られることおよび経済的効果などの点から適宜所望にしたがって決定され、電荷輸送層については、好ましくは５〜５０μｍ、より好ましくは１０〜４０μｍ、最適には２０〜３０μｍとされるのが望ましい。
【００９１】
電荷発生層は、光導電層を機能分離した場合の電荷を発生する機能を主として奏する層である。この電荷発生層は、構成要素として少なくともシリコン原子を含み、実質的に炭素原子を含まず、必要であれば水素原子を含むａ−Ｓｉ：Ｈから成り、所望の光導電特性、特に電荷発生特性、電荷輸送特性を有する。
電荷発生層の層厚は所望の電子写真特性が得られることおよび経済的効果等の点から適宜所望にしたがって決定され、好ましくは０．５〜１５μｍ、より好ましくは１〜１０μｍ、最適には１〜５μｍとされる。
【００９２】
本発明に用いることができるアモルファスシリコン感光体には必要に応じて、上述のようにして支持体上に形成された光導電層の上に、更に表面層を設けることができ、アモルファスシリコン系の表面層を形成することが好ましい。この表面層は自由表面を有し、主に耐湿性、連続繰り返し使用特性、電気的耐圧性、使用環境特性、耐久性において本発明の目的を達成するために設けられる。
本発明における表面層の層厚としては、通常０．０１〜３μｍ、好適には０．０５〜２μｍ、最適には０．１〜１μｍとされるのが望ましいものである。層厚が０．０１μｍよりも薄いと感光体を使用中に摩耗等の理由により表面層が失われてしまい、３μｍを超えると残留電位の増加等の電子写真特性低下がみられる。
【００９３】
本発明のトナーを用いて感光体上の潜像を現像する際に、交互電界を印加する画像形成装置を用いることができる。図５に示した本発明の実施の一例の現像器において、現像時、現像スリーブには、電源により現像バイアスとして、直流電圧に交流電圧を重畳した振動バイアス電圧が印加される。背景部電位と画像部電位は、上記振動バイアス電位の最大値と最小値の間に位置している。これによって現像部に向きが交互に変化する交互電界が形成される。この交互電界中で現像剤のトナーとキャリアが激しく振動し、トナーが現像スリーブおよびキャリアへの静電的拘束力を振り切って感光体ドラムに飛翔し、感光体ドラムの潜像に対応して付着する。
【００９４】
振動バイアス電圧の最大値と最小値の差(ピーク間電圧)は、０．５〜５ｋＶが好ましく、周波数は１〜１０ｋＨｚが好ましい。振動バイアス電圧の波形は、矩形波、サイン波、三角波等が使用できる。振動バイアスの直流電圧成分は、上記したように背景部電位と画像部電位の間の値であるが、画像部電位よりも背景部電位に近い値である方が、背景部電位領域へのかぶりトナーの付着を防止する上で好ましい。
【００９５】
振動バイアス電圧の波形が矩形波の場合、デューティ比を５０％以下とすることが望ましい。ここでデューティ比とは、振動バイアスの１周期中でトナーが感光体に向かおうとする時間の割合である。このようにすることにより、トナーが感光体に向かおうとするピーク値とバイアスの時間平均値との差を大きくすることができるので、トナーの運動がさらに活発化し、トナーが潜像面の電位分布に忠実に付着してざらつき感や解像力を向上させることができる。またトナーとは逆極性の電荷を有するキャリアが感光体に向かおうとするピーク値とバイアスの時間平均値との差を小さくすることができるので、キャリアの運動を沈静化し、潜像の背景部にキャリアが付着する確率を大幅に低減することができる。
【００９６】
図６に接触式の帯電装置を用いた画像形成装置の一例の概略構成を示す。被帯電体、像担持体としての感光体は矢印の方向に所定の速度（プロセススピード）で回転駆動される。この感光ドラムに接触させた帯電部材である帯電ローラは芯金とこの芯金の外周に同心一体にローラ上に形成した導電ゴム層を基本構成とし、芯金の両端を不図示の軸受け部材などで回転自由に保持させると供に、不図示の加圧手段によって感光ドラムに所定の加圧力で押圧させており、本図の場合はこの帯電ローラは感光ドラムの回転駆動に従動して回転する。帯電ローラは、直径９ｍｍの芯金上に１０００００Ω・ｃｍ程度の中抵抗ゴム層を被膜して直径１６ｍｍに形成されている。
帯電ローラの芯金と図示の電源とは電気的に接続されており、電源により帯電ローラに対して所定のバイアスが印加される。これにより感光体の周面が所定の極性、電位に一様に帯電処理される。
【００９７】
本発明で使われる帯電部材の形状としてはローラの他にも、磁気ブラシ、ファーブラシなど、どのような形態をとってもよく、電子写真装置の仕様や形態にあわせて選択可能である。磁気ブラシを用いる場合、磁気ブラシは例えばＺｎ−Ｃｕフェライト等、各種フェライト粒子を帯電部材として用い、これを支持させるための非磁性の導電スリーブ、これに内包されるマグネットロールによって構成される。また、ファーブラシを用いる場合、例えばファーブラシの材質としては、カーボン、硫化銅、金属、および金属酸化物により導電処理されたファーを用い、これを金属や他の導電処理された芯金に巻き付けたり張り付けたりすることで帯電器とする。
【００９８】
図７に本発明のトナーを保持する現像手段を支持するプロセスカートリッジを有する画像形成装置の概略構成を示す。
本発明においては、感光体と、現像手段と、帯電手段、及びクリーニング手段等の構成要素のうち、複数のものをプロセスカートリッジとして一体に結合して構成し、このプロセスカ−トリッジを複写機やプリンター等の画像形成装置本体に対して着脱可能に構成する。
【００９９】
【実施例】
以下実施例により本発明を更に説明するが、本発明はこれに限定されるものではない。以下、部は重量部を示す。
【０１００】
製造例１（有機微粒子エマルションの合成）
攪拌棒及び温度計をセットした反応容器に、水６８３部、メタクリル酸エチレンオキサイド付加物硫酸エステルのナトリウム塩（エレミノールＲＳ−３０：三洋化成工業製）１１部、スチレン１３８部、メタクリル酸１３８部、過硫酸アンモニウム１部を仕込み、４００回転／分で１５分間攪拌したところ、白色の乳濁液が得られた。加熱して、系内温度７５℃まで昇温し５時間反応させた。さらに、１％過硫酸アンモニウム水溶液３０部加え、７５℃で５時間熟成してビニル系樹脂（スチレン−メタクリル酸−メタクリル酸エチレンオキサイド付加物硫酸エステルのナトリウム塩の共重合体）の水性分散液［微粒子分散液１］を得た。
［微粒子分散液１］をレーザ回折／散乱粒度分布測定装置「ＬＡ−９２０」（堀場製作所社製）で測定した平均粒径は、０．１４μｍであった。［微粒子分散液１］の一部を乾燥して樹脂分を単離した。該樹脂分のＴｇは１５２℃であった。
【０１０１】
製造例２（水相の調製）
水９９０部、［微粒子分散液１］８３部、ドデシルジフェニルエーテルジスルホン酸ナトリウムの４８．５％水溶液（エレミノールＭＯＮ−７：三洋化成工業製）３７部、酢酸エチル９０部を混合攪拌し、乳白色の液体を得た。これを［水相１］とする。
【０１０２】
製造例３（低分子ポリエステルの合成）
冷却管、攪拌機及び窒素導入管の付いた反応容器中に、ビスフェノールＡエチレンオキサイド２モル付加物２２０部、ビスフェノールＡプロピレンオキサイド３モル付加物５６１部、テレフタル酸２１８部、アジピン酸４８部及びジブチルチンオキサイド２部を入れ、常圧で２３０℃で８時間反応し、さらに１０〜１５ｍｍＨｇの減圧で５時間反応した後、反応容器に無水トリメリット酸４５部を入れ、１８０℃、常圧で２時間反応し、［低分子ポリエステル１］を得た。［低分子ポリエステル１〕は、数平均分子量２５００、重量平均分子量６７００、Ｔｇ４３℃、酸価２５であった。
【０１０３】
製造例４（中間体ポリエステルの合成）
冷却管、攪拌機及び窒索導入管の付いた反応容器中に、ビスフェノールＡエチレンオキサイド２モル付加物６８２部、ビスフェノールＡプロピレンオキサイド２モル付加物８１部、テレフタル酸２８３部、無水トリメリツト酸２２部及びジブチルチンオキサイド２部を入れ、常圧で２３０℃で８時間反応し、さらに１０〜１５ｍｍＨｇの減圧で５時間反応した［中間体ポリエステル１］を得た。［中間体ポリエステル１］は、数平均分子量２１００、重量平均分子量９５００、Ｔｇ５５℃、酸価０．５、水酸基価４９であった。
次に、冷却管、攪拌機及び窒素導入管の付いた反応容器中に、［中間体ポリエステル１］４１１部、イソホロンジイソシアネート８９部、酢酸エチル５００部を入れ１００℃で５時間反応し、［プレポリマー１］を得た。［プレポリマー１］のイソシアネート基含有率は、１．５３％であった。
【０１０４】
製造例５（ケチミンの合成）
攪拌棒及び温度計をセットした反応容器に、イソホロンジアミン１７０部とメチルエチルケトン７５部を仕込み、５０℃で５時間反応を行い、［ケチミン化合物１］を得た。［ケチミン化合物１］のＨ₂Ｏと反応させた後に測定したアミノ基含有率は、３５．０％であった。
【０１０５】
製造例６（マスターバッチの合成）
水１２００部、カーボンブラック（Ｐｒｉｎｔｅｘ３５、デクサ製）５４０部〔ＤＢＰ吸油量＝４２ｍｌ／１００ｍｇ、ｐＨ＝９．５〕、ポリエステル樹脂１２００部を加え、加圧ニーダーで混合し、混合物を２本ロールを用いて１５０℃で３０分混練後、圧延冷却しパルペライザーで粉砕、［マスターバッチ１］を得た。
【０１０６】
製造例７（油相の作製）
撹拌棒及び温度計をセットした容器に、［低分子ポリエステル１］３７８部、カルナバワックス１１０部、酢酸エチル９４７部を仕込み、撹拌下８０℃に昇温し、８０℃のまま５時間保持した後、１時問で３０℃に冷却した。次いで容器に［マスターバッチ１］５００部、酢酸エチル５００部を仕込み、１時間混合し［原料溶解液１］を得た。
［原料溶解液１］１３２４部を容器に移し、ビーズミル（ウルトラビスコミル、アイメックス社製）を用いて、送液速度１ｋｇ／ｈｒ、ディスク周速度６ｍ／秒、０．５ｍｍジルコニアビーズを８０体積％充填、３パスの条件で、カーボンブラック、ワックスの分散を行った。次いで、［低分子ポリエステル１］の６５％酢酸エチル溶液１３２４部加え、上記条件のビーズミルで１パスし、［顔料・ワックス分散液１］を得た。［顔料・ワックス分散液１］の固形分濃度（１３０℃、３０分）は５０％であった。
【０１０７】
実施例１
（乳化⇒脱溶剤）
［顔料・ワックス分散液１］６４８部、［プレポリマー１］を１５４部、［ケチミン化合物１］６．６部を容器に入れ、ＴＫホモミキサー（特殊機化製）で５，０００ｒｐｍで１分間混合した後、容器に［水相１］１２００部を加え、ＴＫホモミキサーで、回転数１３，０００ｒｐｍで２０分間混合し［乳化スラリー１］を得た。
攪拌機及び温度計をセットした容器に、［乳化スラリー１］を投入し、３０℃で８時間脱溶剤した後、４５℃で４時間熟成を行い、［分散スラリー１］を得た。［分散スラリー１］は、体積平均粒径６．０２μｍ、個数平均粒径５．５７μｍ（マルチサイザーＩＩで測定）であった。
【０１０８】
（洗浄⇒乾燥）
［乳化スラリー１］１００部を減圧濾過した後、以下のように洗浄した。
▲１▼：濾過ケーキにイオン交換水１００部を加え、ＴＫホモミキサーで混合（回転数１２，０００ｒｐｍで１０分間）した後濾過した。
▲２▼：▲１▼の濾過ケーキに１０％水酸化ナトリウム水溶液１００部を加え、ＴＫホモミキサーで混合（回転数１２，０００ｒｐｍ で３０分間）した後、減圧濾過した。このアルカリ洗浄を再度行った。
▲３▼：▲２▼の濾過ケーキに１０％塩酸１００部を加え、ＴＫホモミキサーで混合（回転数１２，０００ｒｐｍで１０分間）した後濾過した。
▲４▼：▲３▼の濾過ケーキにイオン交換水３００部を加え、ＴＫホモミキサーで混合（回転数１２，０００ｒｐｍで１０分間）した後濾過する操作を２回行い［濾過ケーキ１］を得た。
［濾過ケーキ１］を循風乾燥機にて４５℃で４８時間乾燥し、目開き７５μｍメッシュで篩いトナー母体粒子を得た。
【０１０９】
次に、得られた母体粒子１００部、帯電制御剤（オリエント化学社製、ボントロンＥ−８４）０．２５部をＱ型ミキサー（三井鉱山社製）に仕込み、タービン型羽根の周速を５０ｍ／ｓｅｃに設定して混合処理した。この場合、その混合操作は、２分間運転、１分間休止を５サイクル行い、合計の処理時間を１０分間とした。
さらに、疎水性シリカ（Ｈ２０００、クラリアントジャパン社製）を０．５部添加し、混合処理した。この場合、その混合操作は、周速を１５ｍ／ｓｅｃとして３０秒混合１分間休止を５サイクル行った。
以上のようにして、体積平均粒径Ｄｖ６．０５μｍ、個数平均粒径Ｄｎ５．５７μｍ、Ｄｖ／Ｄｎ１．０９（マルチサイザーＩＩで測定）、ＣＰＲ２７０のトナーａを得た。
【０１１０】
実施例２
実施例１の［ケチミン化合物１］６．６部（イソシアネート基：アミノ基＝１００：９６）を６．４部（イソシアネート基：アミノ基＝１００：９３．５）に変更した以外は、実施例１と同様にして体積平均粒径Ｄｖ５．８４μｍ、個数平均粒径Ｄｎ５．３１μｍ、Ｄｖ／Ｄｎ＝１．１１（マルチサイザーＩＩで測定）、ＣＰＲ１８０のトナーｂを得た。
【０１１１】
実施例３
実施例１の［ケチミン化合物１］６．６部（イソシアネート基：アミノ基＝１００：９６）を６．２部（イソシアネート基：アミノ基＝１００：９０）に変更した以外は、実施例１と同様にして体積平均粒径Ｄｖ５．５５μｍ、個数平均粒径Ｄｎ４．８９μｍ、Ｄｖ／Ｄｎ＝１．１４（マルチサイザーＩＩで測定）、ＣＰＲ０のトナーｃを得た。
【０１１２】
比較例１
実施例１の［ケチミン化合物１］６．６部（イソシアネート基：アミノ基＝１００：９６）を６．７部（イソシアネート基：アミノ基＝１００：９７）に変更した以外は、実施例１と同様にして体積平均粒径Ｄｖ６．１１μｍ、個数平均粒径Ｄｎ５．６１μｍ、Ｄｖ／Ｄｎ＝１．０９（マルチサイザーＩＩで測定）、ＣＰＲ０３３０のトナーｄを得た。
【０１１３】
比較例２
実施例１の［ケチミン化合物１］６．６部（イソシアネート基：アミノ基＝１００：９６）を６．９部（イソシアネート基：アミノ基＝１００：１００）に変更した以外は、実施例１と同様にして体積平均粒径Ｄｖ６．１１μｍ、個数平均粒径Ｄｎ５．６１μｍ、Ｄｖ／Ｄｎ１．０９（マルチサイザーＩＩで測定）、ＣＰＲ４５０のトナーｅを得た。
【０１１４】
キャリア製造例
シリコーン樹脂（オルガノストレートシリコーン） １００部
トルエン １００部
γ−（２−アミノエチル）アミノプロピルトリメトキシシラン ５部
カーボンブラック １０部
上記混合物をホモミキサーで２０分間分散し、コート層形成液を調整した。このコート層形成液を流動床型コーティング装置を用いて、粒径５０μｍの球状マグネタイト１０００部の表面にコーティングして磁性キャリアＡを得た。
【０１１５】
上記トナーａ〜ｅ４部に対して、上記磁性キャリアＡ９６部とをボールミルで混合し、二成分現像剤１〜５を作製し、以下の評価を行った。評価結果を表１に示す。
【０１１６】
（地肌汚れ（かぶり）、画像濃度評価、クリーニング性）
上記評価は、感光体に当接するクリーニングブレード及び帯電ローラを有し、未転写トナーをクリーニング部にて回収しリサイクルする機構を有する（株）リコー製複写機 ｉｍａｇｉｏＮＥＯ４５０に、上記現像剤を用いて、現像スリーブの回転方向に対して垂直な方向に１ｃｍ間隔で黒ベタと白ベタを繰り返したＡ４横チャート（画像パターンＡ）を１０万枚コピー後、以下に示す所定の画像を出力し、以下の判断基準を用いて画像評価を行なった。
【０１１７】
地肌汚れ（かぶり）
白紙画像を現像中に停止させ、現像後の感光体上の現像剤をテープ転写し、未転写のテープの画像濃度との差を９３８スペクトロデンシトメーター（Ｘ−Ｒｉｔｅ社製）により測定した。
【０１１８】
画像濃度評価
Ａ４横で１ｃｍ×１ｃｍの黒ベタのチェッカー画像を１枚出力し、画像濃度をＸ−Ｒｉｔｅ（Ｘ−Ｒｉｔｅ社製）により測定した。これを５点測定し平均を求めた。
【０１１９】
クリーニング性評価
クリーニング工程を通過した感光体上の転写残トナーをスコッチテープ（住友スリーエム（株）製）で白紙に移し、それをマクベス反射濃度計ＲＤ５１４型で測定し、ブランクとの差が０．０１以下のものを○（良好）、それを越えるものを×（不良）として評価した。
【０１２０】
（定着性（定着下限温度））
定着ローラとして（株）リコー製複写機ｉｍａｇｉｏＮＥＯ４５０の定着部を改造した装置を用いて、これにリコー製のタイプ６２００紙をセットし複写テストを行った。定着画像をパットで擦った後の画像濃度の残存率が７０％以上となる定着ロール温度をもって定着下限温度とした。
なお、定着ローラの金属シリンダーにはＦｅ材質で厚み０．３４ｍｍのものを使用した。また、面圧は１．０×１０^５Ｐａに設定した。
【０１２１】
【表１】

【０１２２】
【発明の効果】
本発明の静電荷像現像用トナーは、特にリサイクル機構を有する画像形成装置において、長期にわたってかぶりの発生がなく、低温定着性に優れ、高品質なトナー画像を形成することができる。
【図面の簡単な説明】
【図１】本発明の紡錘形状トナーを説明する図である。
【図２】本発明の画像形成装置における定着装置の一例の概略図である。
【図３】本発明の画像形成装置における定着装置の他の例の概略図である。
【図４】本発明に用いるアモルファスシリコン感光体の層構成を説明するための模式的構成図である。
【図５】本発明の交互電界を印加する画像形成装置の現像器の一例の概略図である。
【図６】接触式の帯電装置を用いた画像形成装置の一例の概略構成図である。
【図７】本発明のプロセスカートリッジを有する画像形成装置の概略構成である。
【符合の説明】
１ 定着ローラ
２ 加圧ローラ
３、６ 金属シリンダー
４、７ オフセット防止層
５、８ 加熱ランプ
Ｔ トナー像
Ｓ 支持体（転写紙）
５００ 感光体
５０１ 支持体
５０２ 光導電層
５０３ アモルファスシリコン系表面層
５０４ アモルファスシリコン系電荷注入阻止層
５０５ 電荷発生層
５０６ 電荷輸送層[0001]
BACKGROUND OF THE INVENTION
The present invention relates to an electrostatic charge image developing toner used as a developer for developing an electrostatic charge image in electrophotography, electrostatic recording, electrostatic printing, and the like, and an image forming apparatus (developing apparatus) using the toner. ) More specifically, the present invention relates to a toner for developing an electrostatic image, a developer, and an image forming apparatus used for a copying machine, a laser printer, a plain paper fax machine, and the like using a direct or indirect electrophotographic developing system. Further, the present invention relates to a toner for developing an electrostatic charge image, a developer, and an image forming apparatus used for a full-color copying machine, a full-color laser printer, a full-color plain paper fax machine, and the like using a direct or indirect electrophotographic multicolor developing system.
[0002]
[Prior art]
Conventionally, in an electrophotographic apparatus, an electrostatic recording apparatus, or the like, an electric or magnetic latent image is visualized with toner. For example, in electrophotography, an electrostatic charge image (latent image) is formed on a photoreceptor, and then the latent image is developed with toner to form a toner image. The toner image is usually transferred onto a transfer material such as paper and then fixed by a method such as heating.
[0003]
Toner used for electrostatic image development is generally colored particles in which a binder, a colorant, a charge control agent, and other additives are contained in a binder resin. There is a suspension polymerization method. In the pulverization method, a colorant, a charge control agent, an offset preventing agent and the like are melt-mixed in a thermoplastic resin and uniformly dispersed, and the resulting composition is pulverized and classified to produce a toner. According to the pulverization method, a toner having some excellent characteristics can be produced, but there is a limitation in the selection of the toner material. For example, the composition obtained by melt mixing must be capable of being pulverized and classified by economically usable equipment. From this requirement, the melt-mixed composition must be made sufficiently brittle. Therefore, when the above composition is actually pulverized into particles, a high-range particle size distribution is likely to be formed, and when attempting to obtain a copy image with good resolution and gradation, for example, the particle size Fine powders of 5 μm or less and coarse powders of 20 μm or more must be removed by classification, which has the disadvantage that the toner yield becomes very low. Further, in the pulverization method, it is difficult to uniformly disperse the colorant, the charge control agent, and the like in the thermoplastic resin. The uneven dispersion of the compounding agent adversely affects the fluidity, developability, durability, image quality and the like of the toner.
[0004]
In recent years, in order to overcome these problems in the pulverization method, a toner production method by a suspension polymerization method has been proposed and implemented. However, the toner particles obtained by the suspension polymerization method are spherical and have a drawback of poor cleaning properties. Development / transfer with a low image area ratio results in a small amount of residual toner, and poor cleaning does not pose a problem. However, images with a high image area ratio, such as photographic images, and untransferred images formed due to poor paper feed, etc. Toner may be generated on the photoconductor as untransferred toner, and if accumulated, the image may be soiled. In addition, the charging roller that contacts and charges the photosensitive member is contaminated, and the original charging ability cannot be exhibited. For this reason, a method for obtaining irregularly shaped toner particles by associating resin fine particles obtained by an emulsion polymerization method is disclosed (see Patent Document 1). However, in the toner particles obtained by the emulsion polymerization method, a large amount of the surfactant remains not only on the surface but also inside the particles even after the water washing step, and the environmental stability of the toner charging is impaired. The amount distribution is widened, and the background stain of the obtained image becomes poor. Further, the remaining surfactant contaminates the photoreceptor, the charging roller, the developing roller, etc., and the original charging ability cannot be exhibited.
[0005]
Patent Document 2 proposes a dry toner having a practical sphericity of 0.90 to 1.00 consisting of an extension reaction of urethane-modified polyester as a toner binder for the purpose of improving fluidity, low-temperature fixability, and hot offset. Has been. In addition, it is excellent in powder flowability and transferability when it is a small particle size toner, and is also used in dry toners, especially full-color copiers, etc., which are excellent in both heat storage stability, low-temperature fixability, and hot offset resistance. As a dry toner that is excellent in image glossiness and does not require oil application to a heat roll, and a method for economically obtaining such a dry toner, Patent Document 3 and Patent Document 4 disclose an isocyanate group-containing prepolymer ( A dry toner comprising a toner binder obtained by subjecting A) to an extension reaction and / or a crosslinking reaction, and a colorant, wherein the dry toner is subjected to an extension reaction by an amine (B) in the aqueous medium of (A) and / or A dry toner characterized by comprising particles formed by a crosslinking reaction and a method for producing the same are proposed. However, with the toner obtained by this method, a sufficient image cannot be obtained over a long period of time. In particular, in an image forming apparatus having a recycling mechanism and a strong stress on the toner, the fluidity is inferior by embedding the external additive, and the occurrence of fog is remarkable because the charging property is rapidly inferior.
[0006]
[Patent Document 1]
Japanese Patent No. 2537503
[Patent Document 2]
Japanese Patent Laid-Open No. 11-133665
[Patent Document 3]
JP-A-11-149180
[Patent Document 4]
JP 2000-292981 A
[0007]
[Problems to be solved by the invention]
An object of the present invention is to provide a high-quality toner that does not cause fogging over an extended period of time, particularly in an image forming apparatus having a recycling mechanism.
Another object of the present invention is to provide a toner capable of improving the fixing property at low power consumption and forming a high-quality toner image.
Still another object of the present invention is to provide a developer that does not deteriorate image over a long period of time.
Still another object of the present invention is to provide an image forming apparatus using the toner.
[0008]
[Means for Solving the Problems]
As a result of intensive studies to solve the above problems, the present inventors have found that the amines (B) used in the extension reaction and / or the cross-linking reaction do not react completely and exist as unreacted substances. It has been found that this positively charged substance causes fogging when a negatively charged toner is used in the digital image forming method. An aqueous medium containing resin fine particles is obtained by dissolving or dispersing at least a modified polyester resin capable of reacting with a compound having an active hydrogen group, a colorant, and a release agent in an organic solvent. The organic solvent is removed from the resulting dispersion, and the resin fine particles adhering to the toner surface are washed and detached. In the toner containing at least a toner binder, a colorant, and a release agent obtained as described above, it has been found important to reduce the positively charged components of unreacted materials, and the present invention has been completed.
[0009]
That is, according to the present invention, the following dry toner method and image forming apparatus are provided.
(1) An aqueous system containing resin fine particles, at least in a solution or dispersion formed by dissolving or dispersing a modified polyester resin capable of reacting with a compound having an active hydrogen group, a colorant, and a release agent in an organic solvent It is dispersed in a medium and reacted with a compound having an active hydrogen group which is a crosslinking agent and / or an extender, the organic solvent is removed from the obtained dispersion, and the resin fine particles adhering to the toner surface are washed and removed. A toner for developing an electrostatic charge image, wherein in a toner containing at least a toner binder, a colorant, and a release agent obtained by separation, a CPR representing an amount of a basic substance of the toner is 300 or less.
[0010]
(2) The toner for developing an electrostatic charge image according to (1), wherein the modified polyester resin contains at least a prepolymer having an isocyanate group.
(3) The toner for developing an electrostatic charge image according to (1) or (2), wherein the compound having an active hydrogen group is an amine.
(4) The toner binder is composed of a modified polyester and an unmodified polyester, and the weight ratio of the modified polyester to the unmodified polyester is 5/95 to 80/20. The toner for developing an electrostatic charge image according to any one of 1) to (3).
[0011]
(5) The toner for developing an electrostatic charge image according to any one of (1) to (4), wherein the toner binder has an acid value of 1 to 30 mgKOH / g.
(6) In any one of the above (1) to (5), the resin fine particles are made of at least one resin selected from vinyl resins, polyurethane resins, epoxy resins, and polyester resins. The toner for developing an electrostatic image according to the description.
[0012]
(7) (1) to (6)A developer for developing a two-component electrostatic image, comprising the toner for developing an electrostatic image according to any one of the above and a carrier.
(8) In the image forming apparatus having the toner recycling mechanism, (1) to (1)6)An image forming apparatus using the electrostatic image developing toner according to any one of the above.
(9) In an image forming apparatus in which a toner image on a transfer material is fixed by heating and melting by passing between two rollers, the surface pressure (roller load / contact area) applied between the two rollers is 1. 5 × 10^FiveAn image forming apparatus that performs fixing at Pa or less, wherein (1) to (1)6)An image forming apparatus using the electrostatic image developing toner according to any one of the above.
(10) (1) to (6)An image forming apparatus for forming an image using the electrostatic image developing toner according to any one of the above, wherein a fixing device for fixing the toner is in contact with a heating body including a heating element and the heating body. A fixing device that includes a film and a pressure member that is pressed against a heating body via the film, and that heats and fixes a recording material on which an unfixed image is formed between the film and the pressure member. An image forming apparatus.
(11) (1) to (6)An image forming apparatus for forming an image using the electrostatic image developing toner according to any one of the above, wherein the photoconductor is an amorphous silicon photoconductor.
(12) (1) to (6)An image forming apparatus for forming an image using the electrostatic image developing toner according to any one of the above, wherein an alternating electric field is applied when developing a latent image on a photoreceptor. .
(13) (1) to (6)An image forming apparatus that forms an image using the toner for developing an electrostatic image according to any one of the above, wherein the charging device contacts the charging member with the latent image carrier and applies a voltage to the charging member. An image forming apparatus, characterized in that the image forming apparatus is a charging device that performs charging by means of charging.
(14) In a process cartridge that integrally supports at least one unit selected from a photosensitive member, a developing unit, a charging unit, and a cleaning unit and is detachable from the image forming apparatus main body, the developing unit holds toner. The toners (1) to (1)6)A process cartridge comprising the toner for developing an electrostatic charge image according to claim 1.
[0017]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, the present invention will be described in detail.
(Modified polyester resin that can react with active hydrogen)
Examples of the reactive modified polyester resin (RMPE) capable of reacting with active hydrogen include a polyester prepolymer (A) having an isocyanate group. Examples of the prepolymer (A) include a polycondensate of a polyol (PO) and a polycarboxylic acid (PC) and a polyisocyanate (PIC) reacted with a polyester having active hydrogen. Examples of the group having active hydrogen in the polyester include hydroxyl groups (alcoholic hydroxyl groups and phenolic hydroxyl groups), amino groups, carboxyl groups, mercapto groups, and the like. Among these, alcoholic hydroxyl groups are preferable.
[0018]
Modified polyester (MPE) such as urea-modified polyester is easy to adjust the molecular weight of its polymer component, and is a dry toner, especially oil-less low-temperature fixing characteristics (extensive releasability without a mechanism for applying a release oil to a fixing heating medium) And fixing property). Particularly, a polyester prepolymer whose end is modified with urea can suppress adhesion to a heating medium for fixing while maintaining high fluidity and transparency in the fixing temperature range of the unmodified polyester resin itself.
[0019]
Examples of the polyol (PO) include diol (DIO) and trivalent or higher polyol (TO), and DIO alone or a mixture of DIO and a small amount of TO is preferable. Examples of the diol include alkylene glycol (ethylene glycol, 1,2-propylene glycol, 1,3-propylene glycol, 1,4-butanediol, 1,6-hexanediol, etc.); alkylene ether glycol (diethylene glycol, triethylene glycol, Dipropylene glycol, polyethylene glycol, polypropylene glycol, polytetramethylene ether glycol, etc.); alicyclic diols (1,4-cyclohexanedimethanol, hydrogenated bisphenol A, etc.); bisphenols (bisphenol A, bisphenol F, bisphenol S, etc.) ); Adducts of alkylene oxides (ethylene oxide, propylene oxide, butylene oxide, etc.) of the above alicyclic diols; Alkylene oxide (ethylene oxide, propylene oxide, butylene oxide, etc.), etc. adducts. Among these, preferred are alkylene glycols having 2 to 12 carbon atoms and alkylene oxide adducts of bisphenols, and particularly preferred are alkylene oxide adducts of bisphenols and alkylene glycols having 2 to 12 carbon atoms. It is a combined use.
[0020]
Trivalent or higher polyols (TO) include 3 to 8 or higher polyhydric aliphatic alcohols (glycerin, trimethylolethane, trimethylolpropane, pentaerythritol, sorbitol, etc.); trivalent or higher phenols (Tris) Phenol PA, phenol novolak, cresol novolak, etc.); alkylene oxide adducts of the above trivalent or more polyphenols.
[0021]
Examples of the polycarboxylic acid (PC) include dicarboxylic acid (DIC) and trivalent or higher polycarboxylic acid (TC), and DIC alone or a mixture of DIC and a small amount of TC is preferable.
[0022]
Dicarboxylic acids include alkylene dicarboxylic acids (succinic acid, adipic acid, sebacic acid, etc.); alkenylene dicarboxylic acids (maleic acid, fumaric acid, etc.); aromatic dicarboxylic acids (phthalic acid, isophthalic acid, terephthalic acid, naphthalenedicarboxylic acid, etc.) ) And the like. Of these, preferred are alkenylene dicarboxylic acids having 4 to 20 carbon atoms and aromatic dicarboxylic acids having 8 to 20 carbon atoms. Examples of the trivalent or higher valent polycarboxylic acid include aromatic polycarboxylic acids having 9 to 20 carbon atoms (such as trimellitic acid and pyromellitic acid).
In addition, as polycarboxylic acid, you may make it react with a polyol using the acid anhydride or lower alkyl ester (methyl ester, ethyl ester, isopropyl ester etc.) of the above-mentioned thing.
[0023]
The ratio of the polyol (PO) and the polycarboxylic acid (PC) is usually 2/1 to 1/1, as the equivalent ratio [OH] / [COOH] of the hydroxyl group [OH] and the carboxyl group [COOH], preferably 1.5 / 1 to 1/1, more preferably 1.3 / 1 to 1.02 / 1.
[0024]
As polyisocyanate (PIC), aliphatic polyisocyanate (tetramethylene diisocyanate, hexamethylene diisocyanate, 2,6-diisocyanatomethylcaproate, etc.); alicyclic polyisocyanate (isophorone diisocyanate, cyclohexylmethane diisocyanate, etc.); aromatic Diisocyanates (tolylene diisocyanate, diphenylmethane diisocyanate, etc.); araliphatic diisocyanates (α, α, α ′, α′-tetramethylxylylene diisocyanate, etc.); isocyanurates; And a combination of two or more of these.
[0025]
The ratio of the polyisocyanate (PIC) is usually 5/1 to 1/1, preferably 4 /, as an equivalent ratio [NCO] / [OH] of the isocyanate group [NCO] and the hydroxyl group [OH] of the polyester having a hydroxyl group. 1 to 1.2 / 1, more preferably 2.5 / 1 to 1.5 / 1. When [NCO] / [OH] exceeds 5, low-temperature fixability deteriorates. When the molar ratio of [NCO] is less than 1, in the case of a urea-modified polyester, the urea content in the polyester becomes low and the hot offset resistance deteriorates. The content of the polyisocyanate (PIC) component in the polyester prepolymer (A) having an isocyanate group at the terminal is usually 0.5 to 40% by weight, preferably 1 to 30% by weight, more preferably 2 to 20% by weight. %. If it is less than 0.5% by weight, the hot offset resistance deteriorates, and it is disadvantageous in terms of both heat-resistant storage stability and low-temperature fixability. On the other hand, if it exceeds 40% by weight, the low-temperature fixability deteriorates.
[0026]
The number of isocyanate groups contained per molecule in the polyester prepolymer (A) having an isocyanate group is usually 1 or more, preferably 1.5 to 3 on average, more preferably 1.8 to 2.5 on average. It is a piece. If it is less than 1 per molecule, the molecular weight of the modified polyester will be low, and the hot offset resistance will deteriorate.
[0027]
(Crosslinking agent and extender (compound having an active hydrogen group))
As the compound having an active hydrogen group capable of reacting with a reactive group such as an isocyanate group of the modified polyester used in the present invention, amines (B) can be preferably used.
In the present invention, a urea-modified polyester that is preferably used as a toner binder can be obtained by a reaction between a polyester prepolymer (A) having an isocyanate group and an amine (B).
[0028]
As amines (B), diamine (B1), trivalent or higher polyamine (B2), aminoalcohol (B3), aminomercaptan (B4), amino acid (B5), and amino acids B1 to B5 blocked (B6) etc. are mentioned.
[0029]
Examples of the diamine (B1) include aromatic diamines (phenylenediamine, diethyltoluenediamine, 4,4′diaminodiphenylmethane, etc.); alicyclic diamines (4,4′-diamino-3,3′dimethyldicyclohexylmethane, diaminecyclohexane, Isophorone diamine etc.); and aliphatic diamines (ethylene diamine, tetramethylene diamine, hexamethylene diamine etc.) and the like. Examples of the trivalent or higher polyamine (B2) include diethylenetriamine and triethylenetetramine. Examples of amino alcohol (B3) include ethanolamine and hydroxyethylaniline. Examples of amino mercaptan (B4) include aminoethyl mercaptan and aminopropyl mercaptan. Examples of the amino acid (B5) include aminopropionic acid and aminocaproic acid. Examples of the compound (B6) in which the amino group of B1 to B5 is blocked include ketimine compounds and oxazolidone compounds obtained from the amines of B1 to B5 and ketones (acetone, methyl ethyl ketone, methyl isobutyl ketone, etc.). Among these amines (B), preferred are B1 and a mixture of B1 and a small amount of B2.
[0030]
Furthermore, the molecular weight of a modified polyester such as urea-modified polyester can be adjusted using an extension terminator. Examples of the extension terminator include monoamines (diethylamine, dibutylamine, butylamine, laurylamine, etc.), and those obtained by blocking them (ketimine compounds).
[0031]
The ratio of amines (B) is the equivalent ratio [NCO] / [NHx] of isocyanate groups [NCO] in the prepolymer (A) having isocyanate groups and amino groups [NHx] in amines (B). The ratio is usually 2/1 to 1/2, preferably 1.5 / 1 to 1 / 1.5, and more preferably 1.2 / 1 to 1 / 1.2. When [NCO] / [NHx] exceeds 2 or less than 1/2, the molecular weight of a modified polyester such as urea-modified polyester (UMPE) becomes low, and the hot offset resistance deteriorates. In the present invention, the polyester modified with urea bonds (UMPE) may contain urethane bonds as well as urea bonds. The molar ratio of the urea bond content to the urethane bond content is usually 100/0 to 10/90, preferably 80/20 to 20/80, and more preferably 60/40 to 30/70. When the molar ratio of the urea bond is less than 10%, the hot offset resistance is deteriorated.
[0032]
The modified polyester such as urea-modified polyester (UMPE) used as a toner binder in the present invention is produced by a one-shot method or a prepolymer method.
[0033]
The weight average molecular weight of the modified polyester such as urea-modified polyester is usually 10,000 or more, preferably 20,000 to 10,000,000, and more preferably 30,000 to 1,000,000. If it is less than 10,000, the hot offset resistance deteriorates. The number average molecular weight of the modified polyester such as urea-modified polyester is not particularly limited when the unmodified polyester (PE) described later is used, and may be a number average molecular weight that can be easily obtained to obtain the weight average molecular weight. . In the case of the modified polyester alone, the number average molecular weight is usually 20000 or less, preferably 1000 to 10000, and more preferably 2000 to 8000. When it exceeds 20000, the low-temperature fixability and the glossiness when used in a full-color device are deteriorated.
[0034]
(Unmodified polyester (PE))
In the present invention, the modified polyester (MPE) can be used not only alone, but also with the MPE, unmodified polyester (PE) can be contained as a toner binder component. By using PE together, the low-temperature fixability and the gloss when used in a full-color apparatus are improved, which is preferable to single use. Examples of PE include polycondensates of polyol (PO) and polycarboxylic acid (PC) similar to those used in the modified polyester such as UMPE, and preferred ones are the same as in the case of modified polyester. . In addition, PE may be modified not only with unmodified polyester but also with a chemical bond other than a urea bond, for example, with a urethane bond. It is preferable that MPE and PE are at least partially compatible in terms of low-temperature fixability and hot offset resistance. Therefore, a similar composition is preferable for the polyester component of MPE and PE. When PE is contained, the weight ratio of MPE to PE is usually 5/95 to 80/20, preferably 5/95 to 30/70, more preferably 5/95 to 25/75, and particularly preferably 7/93. ~ 20/80. If the weight ratio of MPE is less than 5%, the hot offset resistance deteriorates, and it is disadvantageous in terms of both heat-resistant storage stability and low-temperature fixability.
[0035]
The peak molecular weight of PE is usually 1000-30000, preferably 1500-10000, more preferably 2000-8000. If it is less than 1000, the heat-resistant storage stability deteriorates, and if it exceeds 10,000, the low-temperature fixability deteriorates. The hydroxyl value of PE is preferably 5 or more, more preferably 10 to 120, and particularly preferably 20 to 80. If it is less than 5, it is disadvantageous in terms of both heat-resistant storage stability and low-temperature fixability. The acid value of PE is usually 1 to 30 mgKOH / g, preferably 5 to 20 mgKOH / g. By giving the acid value, it tends to be negatively charged, and the background stains are lessened. Furthermore, when fixing to paper, the affinity between the paper and the toner is good and the low-temperature fixability is improved.
[0036]
In the present invention, the glass transition point (Tg) of the toner binder is usually 50 to 70 ° C., preferably 55 to 65 ° C. If it is less than 50 ° C., the heat resistant storage stability of the toner is deteriorated, and if it exceeds 70 ° C., the low-temperature fixability becomes insufficient. Due to the coexistence of the modified polyester resin, the dry toner of the present invention tends to have good heat-resistant storage stability even when the glass transition point is low, as compared with known polyester toners. The storage elastic modulus of the toner binder is 10,000 dyne / cm at a measurement frequency of 20 Hz.²The temperature (TG ′) at which the temperature becomes is usually 100 ° C. or higher, preferably 110 to 200 ° C. If it is less than 100 ° C., the resistance to hot offset deteriorates. As the viscosity of the toner binder, the temperature (Tη) at 1000 poise at a measurement frequency of 20 Hz is usually 180 ° C. or lower, preferably 90 to 160 ° C. If it exceeds 180 ° C., the low-temperature fixability deteriorates. That is, TG ′ is preferably higher than Tη from the viewpoint of achieving both low temperature fixability and hot offset resistance. In other words, the difference between TG ′ and Tη (TG′−Tη) is preferably 0 ° C. or more. More preferably, it is 10 degreeC or more, Most preferably, it is 20 degreeC or more. The upper limit of the difference is not particularly limited. Further, from the viewpoint of achieving both heat-resistant storage stability and low-temperature fixability, the difference between Tη and Tg is preferably 0 to 100 ° C. More preferably, it is 10-90 degreeC, Most preferably, it is 20-80 degreeC.
[0037]
(Coloring agent)
As the colorant used in the present invention, all known dyes and pigments can be used. For example, carbon black, nigrosine dye, iron black, naphthol yellow S, Hansa yellow (10G, 5G, G), cadmium yellow, yellow iron oxide, ocher, yellow lead, 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, Iso Indolinone Yellow, Bengala, Pangdan, Lead Red, Cadmium Red, Cadmium Mercury Red, Antimony Zhu, Permanent Red 4R, Para Red, Faise Red, Parachlor Ortho Nitroaniline Red, Resol Fast Scarlet G, Brilli Fast Scarlet, Brilliant Carmine BS, Permanent Red (F2R, F4R, FRL, FRLL, F4RH), Fast Scarlet VD, Belkan Fast Rubin B, Brilliant Scarlet G, Resol Rubin GX, Permanent Red F5R, Brilliant Carmine 6B, Pogment Scarlet 3B, Bordeaux 5B, Toluidine Maroon, Permanent Bordeaux F2K, Helio Bordeaux BL, Bordeaux 10B, Bon Maroon Light, Bon Maroon Medium, 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 oren , Perinone orange, oil orange, cobalt blue, cerulean blue, alkaline blue rake, peacock blue rake, Victoria blue rake, metal-free phthalocyanine blue, phthalocyanine blue, fast sky blue, indanthrene blue (RS, BC), indigo, Ultramarine blue, bitumen, anthraquinone blue, fast violet B, methyl violet lake, cobalt purple, manganese purple, 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, Titanium Oxide, Zinc white, litbon and mixtures thereof can be used. The content of the colorant is usually 1 to 15% by weight, preferably 3 to 10% by weight, based on the toner.
[0038]
The colorant used in the present invention can also be used as a master batch combined with a resin. As the binder resin to be kneaded together with the production of the master batch or the master batch, in addition to the above-mentioned modified and unmodified polyester resins, styrene such as polystyrene, poly p-chlorostyrene, polyvinyltoluene, and polymers 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, styrene-methyl methacrylate copolymer, styrene-ethyl methacrylate copolymer, styrene-butyl methacrylate copolymer, styrene-α- Chloromethyl methacrylate copolymer, Len-acrylonitrile copolymer, styrene-vinyl methyl ketone copolymer, styrene-butadiene copolymer, styrene-isoprene copolymer, styrene-acrylonitrile-indene copolymer, styrene-maleic acid copolymer, styrene-maleic acid Styrene copolymers such as acid ester copolymers; polymethyl methacrylate, polybutyl methacrylate, polyvinyl chloride, polyvinyl acetate, polyethylene, polypropylene, polyester, epoxy resin, epoxy polyol resin, polyurethane, polyamide, polyvinyl butyral, poly Acrylic acid resin, rosin, modified rosin, terpene resin, aliphatic or alicyclic hydrocarbon resin, aromatic petroleum resin, chlorinated paraffin, paraffin wax and the like can be used alone or in combination. .
[0039]
This master batch can be obtained by mixing and kneading a resin for a master batch and a colorant under a high shear force to obtain a master batch. At this time, an organic solvent can be used to enhance the interaction between the colorant and the resin. Also, a so-called flushing method called watering paste containing water of a colorant is mixed and kneaded together with a resin and an organic solvent, and the colorant is transferred to the resin side to remove moisture and organic solvent components. Since it can be used as it is, it does not need to be dried and is preferably used. For mixing and kneading, a high shear dispersion device such as a three-roll mill is preferably used.
[0040]
(Release agent)
As the release agent used in the present invention, various conventionally known release agents are used. Such materials include carnauba wax, montan wax, oxidized rice wax, synthetic ester wax, solid silicone varnish, higher fatty acid higher alcohol, montan ester wax, and low molecular weight polypropylene wax. These can be used alone or in combination, but carnauba wax, montan wax, oxidized rice wax, and synthetic ester wax are particularly preferable in terms of achieving both low-temperature fixability and hot offset property. The carnauba wax is a natural wax obtained from the leaves of carnauba palm, but a microcrystalline one is preferable, and an acid value of 5 mgKOH / g or less is preferable because it can be uniformly dispersed in the binder resin. . Further, a low acid value type from which free fatty acids are eliminated is more preferred. The montan wax generally refers to a montan wax refined from a mineral, and like a carnauba wax, it is preferably a microcrystal and an acid value of 5 to 14 mgKOH / g. Oxidized rice wax is a natural wax obtained by refining crude wax produced in a dewaxing or wintering process when refining rice bran oil extracted from rice bran, and its acid value is 10 to 30 mgKOH / g is preferred. Synthetic ester wax is synthesized by ester reaction from monofunctional linear fatty acid and monofunctional linear alcohol.
[0041]
(Resin fine particles)
As the resin fine particles used in the present invention, any resin can be used as long as it can form an aqueous dispersion, and it may be a thermoplastic resin or a thermosetting resin. Examples of such resins include vinyl resins, polyurethane resins, epoxy resins, polyester resins, polyamide resins, polyimide resins, silicon resins, phenol resins, melamine resins, urea resins, aniline resins, ionomer resins, and polycarbonate resins. Is mentioned. The resin fine particles may be a combination of two or more of the above resins. Among these, those made of a vinyl resin, a polyurethane resin, an epoxy resin, a polyester resin, and a resin using a combination thereof are preferable because an aqueous dispersion of fine spherical resin particles is easily obtained.
[0042]
The vinyl resin is a polymer obtained by homopolymerization or copolymerization of a vinyl monomer, such as a styrene- (meth) acrylate resin, a styrene-butadiene copolymer, a (meth) acrylic acid-acrylate polymer, Examples include styrene-acrylonitrile copolymers, styrene-maleic anhydride copolymers, styrene- (meth) acrylic acid copolymers, and the like. The average particle diameter of the resin fine particles is 5 to 2000 nm, preferably 20 to 300 nm.
[0043]
(Charge control agent)
The toner of the present invention may contain a charge control agent as necessary. Any known charge control agent can be used, for example, nigrosine dyes, triphenylmethane dyes, chromium-containing metal complex dyes, molybdate chelate pigments, rhodamine dyes, alkoxy amines, quaternary ammonium salts (fluorine-modified) Quaternary ammonium salts), alkylamides, phosphorus simple substances or compounds, tungsten simple substances or compounds, fluorine-based activators, salicylic acid metal salts, metal salts of salicylic acid derivatives, and the like. Specifically, Nitronine-based dye Bontron 03, quaternary ammonium salt Bontron P-51, metal-containing azo dye Bontron S-34, oxynaphthoic acid metal complex E-82, salicylic acid metal complex E- 84, E-89 of a phenol-based condensate (manufactured by Orient Chemical Industry Co., Ltd.), TP-302 of a quaternary ammonium salt molybdenum complex, TP-415 (manufactured by Hodogaya Chemical Industry Co., Ltd.), quaternary ammonium Copy charge PSY VP2038 of salt, copy blue PR of triphenylmethane derivative, copy charge of quaternary ammonium salt NEG VP2036, copy charge NX VP434 (manufactured by Hoechst), LRA-901, LR-147 which is a boron complex (Nippon Carlit), copper phthalocyanine, perylene, quinaclide And azo pigments, and other high molecular compounds having a functional group such as a sulfonic acid group, a carboxyl group, and a quaternary ammonium salt.
[0044]
In the present invention, the amount of charge control agent used is determined uniquely by the type of binder resin, the presence or absence of additives used as necessary, and the toner production method including the dispersion method, and is uniquely limited. However, it is preferably used in the range of 0.1 to 10 parts by weight with respect to 100 parts by weight of the binder resin. The range of 0.2 to 5 parts by weight is preferable. When the amount exceeds 10 parts by weight, the chargeability of the toner is too high, the effect of the main charge control agent is reduced, the electrostatic attractive force with the developing roller is increased, the flowability of the developer is reduced, and the image density is reduced. Incurs a decline. These charge control agents can be melt-kneaded together with the masterbatch and the resin, or may be added when dissolved or dispersed in an organic solvent, or may be fixed on the toner surface after preparation of toner particles.
[0045]
(External additive)
As the external additive for assisting the fluidity, developability and chargeability of the colored particles obtained in the present invention, inorganic fine particles can be preferably used. The primary particle diameter of the inorganic fine particles is preferably 5 mμ to 2 μm, and particularly preferably 5 mμ to 500 mμ. The specific surface area according to the BET method is 20 to 500 m.²/ G is preferable. The proportion of the inorganic fine particles used is preferably 0.01 to 5% by weight of the toner, and particularly preferably 0.01 to 2.0% by weight. Specific examples of the inorganic fine particles include, for example, silica, alumina, titanium oxide, barium titanate, magnesium titanate, calcium titanate, strontium titanate, zinc oxide, tin oxide, quartz sand, clay, mica, wollastonite, diatomaceous earth. Examples include soil, chromium oxide, cerium oxide, bengara, antimony trioxide, magnesium oxide, zirconium oxide, barium sulfate, barium carbonate, calcium carbonate, silicon carbide, and silicon nitride.
[0046]
Other polymer fine particles such as polystyrene, methacrylic acid ester, acrylic acid ester copolymer obtained by soap-free emulsion polymerization, suspension polymerization, and dispersion polymerization, polycondensation system such as silicone, benzoguanamine, nylon, thermosetting resin, etc. Examples include polymer particles.
[0047]
Such external additives can be surface treated to increase hydrophobicity and prevent deterioration of flow characteristics and charging characteristics even under high humidity. For example, silane coupling agents, silylating agents, silane coupling agents having an alkyl fluoride group, organic titanate coupling agents, aluminum coupling agents, silicone oils, modified silicone oils and the like are preferable surface treatment agents. .
[0048]
Examples of the cleaning property improver for removing the developer after transfer remaining on the photoreceptor or the primary transfer medium include, for example, zinc stearate, calcium stearate, fatty acid metal salts such as stearic acid, such as polymethyl methacrylate fine particles, polystyrene fine particles, etc. And polymer fine particles produced by soap-free emulsion polymerization. The polymer fine particles preferably have a relatively narrow particle size distribution and a volume average particle size of 0.01 to 1 μm.
[0049]
(Production method)
The toner binder can be produced by the following method. Polyol (PO) and polycarboxylic acid (PC) are heated to 150-280 ° C. in the presence of a known esterification catalyst such as tetrabutoxytitanate, dibutyltin oxide, etc., and the generated water is distilled off as necessary. Thus, a polyester having a hydroxyl group is obtained. Next, this is reacted with polyisocyanate (PIC) at 40 to 140 ° C. to obtain a prepolymer (A) having an isocyanate group. Further, this A is reacted with amines (B) at 0 to 140 ° C. to obtain a polyester modified with a urea bond. When reacting PIC and when A and B are reacted, a solvent may be used as necessary. Usable solvents include aromatic solvents (toluene, xylene, etc.); ketones (acetone, methyl ethyl ketone, methyl isobutyl ketone)
And esters such as ethyl acetate, amides (dimethylformamide, dimethylacetamide, etc.) and ethers (tetrahydrofuran, etc.). When polyester (PE) that is not modified with a urea bond is used in combination, PE is produced in the same manner as the polyester having a hydroxyl group, and this is dissolved in the solution after completion of the UMPE reaction and mixed.
[0050]
The dry toner of the present invention can be produced by the following method, but is not limited thereto.
(Toner production method in aqueous medium)
The aqueous medium used in the present invention may be water alone, or a solvent miscible with water may be used in combination. Examples of the miscible solvent include alcohol (methanol, isopropanol, ethylene glycol, etc.), dimethylformamide, tetrahydrofuran, cellosolves (methylcellosolve, etc.), lower ketones (acetone, methyl ethyl ketone, etc.) and the like. The toner particles may be formed by reacting a dispersion containing an isocyanate group-containing polyester prepolymer (A) with an amine (B) in an aqueous medium, or a modified polyester such as a urea-modified polyester manufactured in advance. It may be formed by reacting with. As a method for stably forming a dispersion containing a modified polyester such as urea-modified polyester or a prepolymer (A) in an aqueous medium, the composition of the toner raw material containing the modified polyester or prepolymer (A) in the aqueous medium may be used. And a method of dispersing by shearing force. The prepolymer (A) and other toner components (hereinafter referred to as toner raw materials), a colorant, a colorant masterbatch, a release agent, an unmodified polyester, and the like are mixed when forming a dispersion in an aqueous medium. However, it is more preferable to dissolve or disperse the toner raw material in an organic solvent in advance to form a solution or dispersion, and then add and dissolve the solution or dispersion in an aqueous medium.
[0051]
The dispersion method is not particularly limited, and known equipment such as a low-speed shear method, a high-speed shear method, a friction method, a high-pressure jet method, and an ultrasonic wave can be applied. In order to make the particle size of the dispersion 2 to 20 μm, a high-speed shearing type is preferable. When a high-speed shearing disperser is used, the number of rotations is not particularly limited, but is usually 1000 to 30000 rpm, preferably 5000 to 20000 rpm. The dispersion time is not particularly limited, but in the case of a batch method, it is usually 0.1 to 5 minutes. The temperature during dispersion is usually 0 to 150 ° C. (under pressure), preferably 40 to 98 ° C. Higher temperatures are preferred in that the dispersion of the modified polyester or prepolymer (A) has a low viscosity and is easily dispersed.
[0052]
The amount of the aqueous medium used is usually 50 to 2000 parts by weight, preferably 100 to 1000 parts by weight, based on 100 parts of the toner composition containing a modified polyester such as urea-modified polyester and the prepolymer (A). If the amount is less than 50 parts by weight, the dispersion state of the toner composition is poor, and toner particles having a predetermined particle diameter cannot be obtained. If it exceeds 20000 parts by weight, it is not economical. Moreover, a dispersing agent can also be used as needed. It is preferable to use a dispersant because the particle size distribution becomes sharp and the dispersion is stable.
[0053]
In the step of synthesizing a modified polyester such as urea-modified polyester from the polyester prepolymer (A), the amine (B) may be added and reacted before dispersing the toner composition in the aqueous medium. After the dispersion, an amine (B) may be added to cause a reaction from the particle interface. In this case, the modified polyester is preferentially generated on the surface of the toner to be produced, and a concentration gradient can be provided inside the particles.
[0054]
As a dispersant for emulsifying and dispersing the oily phase in which the toner composition is dispersed in a liquid containing water, anionic surfactants such as alkylbenzene sulfonates, α-olefin sulfonates, and phosphate esters, alkyls Amine salt type such as amine salt, amino alcohol fatty acid derivative, polyamine fatty acid derivative, imidazoline, alkyltrimethylammonium salt, dialkyldimethylammonium salt, alkyldimethylbenzylammonium salt, pyridinium salt, alkylisoquinolinium salt, benzethonium chloride, etc. Quaternary ammonium salt type cationic surfactants, fatty acid amide derivatives, non-ionic surfactants such as polyhydric alcohol derivatives such as alanine, dodecyldi (aminoethyl) glycine, di (octylaminoethyl) glycine and N-alkyl -N, N - amphoteric surfactants, such as dimethyl ammonium betaine and the like.
[0055]
Further, by using a surfactant having a fluoroalkyl group, the effect can be obtained in a very small amount. Preferred anionic surfactants having a fluoroalkyl group include fluoroalkyl carboxylic acids having 2 to 10 carbon atoms and metal salts thereof, disodium perfluorooctanesulfonyl glutamate, 3- [omega-fluoroalkyl (C6-C11 ) Oxy] -1-alkyl (C3-C4) sodium sulfonate, 3- [omega-fluoroalkanoyl (C6-C8) -N-ethylamino] -1-propanesulfonic acid sodium, fluoroalkyl (C11-C20) carvone Acids and metal salts thereof, perfluoroalkylcarboxylic acids (C7 to C13) and metal salts thereof, perfluoroalkyl (C4 to C12) sulfonic acids and metal salts thereof, perfluorooctanesulfonic acid diethanolamide, N-propyl-N- (2-hydroxyethyl ) Perfluorooctanesulfonamide, perfluoroalkyl (C6-C10) sulfonamidopropyltrimethylammonium salt, perfluoroalkyl (C6-C10) -N-ethylsulfonylglycine salt, monoperfluoroalkyl (C6-C16) ethyl phosphate Etc.
[0056]
Product names include Surflon S-111, S-112, S-113 (Asahi Glass Co., Ltd.), Florard FC-93, FC-95, FC-98, FC-129 (Sumitomo 3M Co., Ltd.), Unidyne DS-101. DS-102 (manufactured by Daikin Industries, Ltd.), MegaFuck F-110, F-120, F-113, F-191, F-812, F-833 (manufactured by Dainippon Ink, Inc.), Xtop EF-102, 103, 104, 105, 112, 123A, 123B, 306A, 501, 201, 204 (manufactured by Tochem Products), and Fgentent F-100, F150 (manufactured by Neos).
[0057]
Examples of cationic surfactants include aliphatic primary, secondary or tertiary amine acids having a fluoroalkyl group, aliphatic quaternary ammonium salts such as perfluoroalkyl (C6-C10) sulfonamidopropyltrimethylammonium salts, and benzaza. Luconium salt, benzethonium chloride, pyridinium salt, imidazolinium salt, trade names include Surflon S-121 (Asahi Glass), Florard FC-135 (Sumitomo 3M), Unidyne DS-202 (Daikin Industries) , Megafac F-150, F-824 (Dainippon Ink Co., Ltd.), Xtop EF-132 (Tochem Products Co., Ltd.), Footgent F-300 (Neos Co., Ltd.), and the like.
[0058]
Further, tricalcium phosphate, calcium carbonate, titanium oxide, colloidal silica, hydroxyapatite and the like can be used as an inorganic compound dispersant that is hardly soluble in water.
[0059]
Further, the dispersed droplets may be stabilized by a polymer protective colloid. For example, acrylic acid, methacrylic acid, α-cyanoacrylic acid, α-cyanomethacrylic acid, itaconic acid, crotonic acid, fumaric acid, maleic acid or maleic anhydride and other (meth) acrylic monomers containing hydroxyl groups Bodies such as β-hydroxyethyl acrylate, β-hydroxyethyl methacrylate, β-hydroxypropyl acrylate, β-hydroxypropyl methacrylate, γ-hydroxypropyl acrylate, γ-hydroxypropyl methacrylate, 3-acrylate Chloro-2-hydroxypropyl, 3-chloro-2-hydroxypropyl methacrylate, diethylene glycol monoacrylate, diethylene glycol monomethacrylate, glycerol monoacrylate, glycerol monomethacrylate, N -Methylol acrylamide, N-methylol methacrylamide, etc., vinyl alcohol or ethers with vinyl alcohol, such as vinyl methyl ether, vinyl ethyl ether, vinyl propyl ether, etc., or esters of compounds containing vinyl alcohol and carboxyl groups, such as Vinyl acetate, vinyl propionate, vinyl butyrate, etc., acrylamide, methacrylamide, diacetone acrylamide or their methylol compounds, acid chlorides such as acrylic acid chloride, methacrylic acid chloride, pinyl pyridine, vinyl pyrrolidone, vinyl imidazole, ethyleneimine, etc. Homopolymers or copolymers such as those having nitrogen atoms or heterocyclic rings thereof, polyoxyethylene, polyoxypropylene, polyoxy Tylene alkylamine, polyoxypropylene alkylamine, polyoxyethylene alkylamide, polyoxypropylene alkylamide, polyoxyethylene nonyl phenyl ether, polyoxyethylene lauryl phenyl ether, polyoxyethylene stearyl phenyl ester, polyoxyethylene nonyl phenyl ester, etc. Celluloses such as polyoxyethylene, methylcellulose, hydroxyethylcellulose, hydroxypropylcellulose and the like can be used.
[0060]
If an acid such as calcium phosphate salt or an alkali-soluble substance is used as the dispersion stabilizer, the calcium phosphate salt is removed from the fine particles by dissolving the calcium phosphate salt with an acid such as hydrochloric acid and then washing with water. To do. It can also be removed by operations such as enzymatic degradation.
[0061]
When a dispersant is used, the dispersant may remain on the surface of the toner particles. However, it is preferable from the charged surface of the toner that the dispersant is washed and removed after the stretching and / or crosslinking reaction.
[0062]
Furthermore, in order to lower the viscosity of the liquid containing the toner composition, a modified polyester such as urea-modified polyester or a solvent in which the prepolymer (A) is soluble can be used. The use of a solvent is preferable in that the particle size distribution becomes sharp. The solvent is preferably volatile with a boiling point of less than 100 ° C. from the viewpoint of easy removal. Examples of the solvent include toluene, xylene, benzene, carbon tetrachloride, methylene chloride, 1,2-dichloroethane, 1,1,2-trichloroethane, trichloroethylene, chloroform, monochlorobenzene, dichloroethylidene, methyl acetate, ethyl acetate, Methyl ethyl ketone, methyl isobutyl ketone and the like can be used alone or in combination of two or more. In particular, aromatic solvents such as toluene and xylene and halogenated hydrocarbons such as methylene chloride, 1,2-dichloroethane, chloroform and carbon tetrachloride are preferred. The usage-amount of the solvent with respect to 100 parts of prepolymers (A) is 0-300 parts normally, Preferably it is 0-100 parts, More preferably, it is 25-70 parts. When a solvent is used, it is removed by heating under normal pressure or reduced pressure after the extension and / or crosslinking reaction.
[0063]
The extension and / or crosslinking reaction time is selected depending on the reactivity of the prepolymer having active hydrogen such as polyester prepolymer (A) and the combination of the crosslinking agent and amines (B) as the extension agent. 10 minutes to 40 hours, preferably 2 to 24 hours. The reaction temperature is generally 0 to 150 ° C, preferably 40 to 98 ° C. Moreover, a well-known catalyst can be used as needed. Specific examples include dibutyltin laurate and dioctyltin laurate.
[0064]
In order to remove the organic solvent from the obtained emulsified dispersion (dispersion), a method of gradually raising the temperature of the entire system and completely removing the organic solvent in the droplets by evaporation can be employed. Alternatively, the emulsified dispersion can be sprayed into a dry atmosphere to completely remove the water-insoluble organic solvent in the droplets to form toner fine particles, and the aqueous dispersant can be removed by evaporation together. . As a dry atmosphere in which the emulsified dispersion is sprayed, a gas obtained by heating air, nitrogen, carbon dioxide gas, combustion gas, or the like, in particular, various air currents heated to a temperature equal to or higher than the boiling point of the highest boiling solvent used is generally used. Sufficient quality can be obtained with a short processing time such as spray dryer, belt dryer, rotary kiln.
[0065]
When the particle size distribution at the time of emulsification dispersion is wide and washing and drying processes are performed while maintaining the particle size distribution, the particle size distribution can be adjusted by classifying into a desired particle size distribution.
In the classification operation, the fine particle portion can be removed in the liquid by a cyclone, a decanter, centrifugation, or the like. Of course, the classification operation may be performed after obtaining the powder as a powder after drying, but it is preferably performed in a liquid in terms of efficiency. The unnecessary fine particles or coarse particles obtained can be returned to the kneading step and used for the formation of particles. At that time, fine particles or coarse particles may be wet.
[0066]
The dispersant used is preferably removed from the obtained dispersion as much as possible, but it is preferable to carry out it simultaneously with the classification operation described above.
[0067]
The resulting dried toner powder is mixed with different kinds of particles such as charge controllable fine particles and fluidizing agent fine particles, or fixed and fused on the surface by applying mechanical impact force to the mixed powder. In addition, it is possible to prevent the detachment of the foreign particles from the surface of the obtained composite particle.
[0068]
Specific means include a method of applying an impact force to the mixture by blades rotating at high speed, a method of injecting and accelerating the mixture into a high-speed air stream, and causing particles or composite particles to collide with an appropriate collision plate, etc. is there. As equipment, Ong mill (manufactured by Hosokawa Micron Co., Ltd.), I-type mill (manufactured by Nippon Pneumatic Co., Ltd.) has been modified to reduce the pulverization air pressure, hybridization system (manufactured by Nara Machinery Co., Ltd.), kryptron Examples include a system (manufactured by Kawasaki Heavy Industries, Ltd.) and an automatic mortar.
[0069]
The toner of the present invention is obtained by the above method, and has a CPR representing the amount of the basic substance in the toner of 300 or less, preferably 200 or less, more preferably 100 or less. Most preferably, 0 is an essential condition for providing an image with little occurrence of background stains over a long period of time. In particular, in an image forming apparatus having a recycling mechanism, the effect of toner base particles is significant, and thus the effect is high. CPR is measured by the method described in JIS K 1557. CPR is a method for displaying the amount of basic substances present in a polyether, and corresponds to the item of total basicity, which is the same measurement method in ASTM.
[0070]
The toner of the present invention is, for example, a toner that can be extended and / or crosslinked by the following reaction. At this time, the following reaction does not occur completely, and if unreacted amines (B) are present, NH_Three ⁺Group and NH₂As a group, it is present in the toner as a positively charged component in terms of polarity.
[0071]
Reaction formula
(A) Polyester prepolymer having an isocyanate group
(B) Amines
[Chemical 1]

[0072]
In addition, in the toner of the present invention, in addition to amino groups, cations such as Na that are not completely washed contained in a surfactant or the like are simultaneously measured as CPR values. Therefore, it is present as a positively charged component in the toner and causes fogging. Therefore, the CPR should be 300 or less.
[0073]
In the present invention, in order to achieve CPR of 300 or less, the following methods are mentioned. By adjusting the mixing ratio, reaction temperature, and reaction time of the reactive group (the isocyanate group of the prepolymer (A) having an isocyanate group and the amino group of the amine (B)), the reaction is completed, and NH_Three ⁺Reducing the residual rate of unreacted amino groups (B) that may be present as cations such as⁺It is important to reduce the amount of residual matter depending on the treatment amount of the active agent and the like that may be present as cations, washing conditions, and the like. In particular, the ratio of isocyanate groups to amino groups is an important factor, preferably 100: 96 to 100: 80, and more preferably 100: 96 to 100: 90. The isocyanate group content can be determined by the method described in JIS K 7301. The amino group content can be determined by the method described in JIS K 7245.
[0074]
(Carrier for two components)
When the toner of the present invention is used for a two-component developer, it may be used by mixing with a magnetic carrier, and the content ratio of the carrier and the toner in the developer is 1 to 10 wt. Part is preferred. As the magnetic carrier, conventionally known ones such as iron powder, ferrite powder, magnetite powder, magnetic resin carrier having a particle diameter of about 20 to 200 μm can be used. Examples of the coating material include amino resins such as urea-formaldehyde resin, melamine resin, benzoguanamine resin, urea resin, polyamide resin, and epoxy resin. Polyvinyl and polyvinylidene resins such as acrylic resins, polymethyl methacrylate resins, polyacrylonitrile resins, polyvinyl acetate resins, polyvinyl alcohol resins, polyvinyl butyral resins, polystyrene resins and styrene acrylic copolymer resins, Halogenated olefin resins such as vinyl, polyester resins such as polyethylene terephthalate resin and polybutylene terephthalate resin, polycarbonate resins, polyethylene resins, polyvinyl fluoride resins, polyvinylidene fluoride resins, polytrifluoroethylene resins, polyhexafluoro Propylene resin, copolymer of vinylidene fluoride and acrylic monomer, copolymer of vinylidene fluoride and vinyl fluoride, tetrafluoroethylene and vinylidene fluoride and non- Monomers including a fluoro terpolymers such, and silicone resins. Moreover, you may contain electrically conductive powder etc. in coating resin as needed. As the conductive powder, metal powder, carbon black, titanium oxide, tin oxide, zinc oxide or the like can be used. These conductive powders preferably have an average particle diameter of 1 μm or less. When the average particle diameter is larger than 1 μm, it becomes difficult to control electric resistance.
[0075]
The toner of the present invention can also be used as a one-component magnetic toner that does not use a carrier or a non-magnetic toner.
[0076]
Next, the shape of the toner preferably used in the present invention will be described. The toner of the present invention preferably has a spindle shape as shown in FIG.
An irregular shape or a flat shape having a non-constant toner shape has the following problems due to poor powder flowability. Since frictional charging cannot be performed smoothly, problems such as background stains are likely to occur. When developing a minute latent image dot, the dot reproducibility is inferior because it is difficult to obtain a dense and uniform toner arrangement. In the electrostatic transfer method, the transfer efficiency is inferior due to being hardly affected by the lines of electric force.
When the toner is close to a true sphere, the powder fluidity is too good and excessively acts on the external force, so that there is a problem that the toner particles are likely to be scattered outside the dots during development and transfer. . In addition, since the spherical toner easily rolls on the photosensitive member, there is a problem that the toner often gets into the gap between the photosensitive member and the cleaning member, resulting in poor cleaning.
[0077]
In the spindle-shaped toner of the present invention, the powder fluidity is appropriately adjusted, so that the triboelectric charging is smoothly performed and the background stain is not generated, and the minute latent image dots are developed in an orderly manner. After that, it is efficiently transferred and has excellent dot reproducibility. In addition, the powder flowability is moderately braked to prevent scattering at that time. The spindle-shaped toner has a limited rolling axis as compared with the spherical toner, and therefore, it is difficult to cause a cleaning defect such as to sink under the cleaning member.
[0078]
The toner of the present invention has a major axis / minor axis ratio (r2 / r1) of 0.5 to 0.8 and a thickness / minor axis ratio (r3 / r2) of 0.7 to 1.0. It is more preferable that the spindle shape be expressed. If the ratio of the major axis to the minor axis (r2 / r1) is less than 0.5, the separation from the true spherical shape is high, but the cleaning property is high, but the dot reproducibility and transfer efficiency are inferior, resulting in high quality image quality. Disappear. When the ratio of the major axis to the minor axis (r2 / r1) exceeds 0.8, it becomes close to a sphere, and cleaning failure may occur particularly in a low temperature and low humidity environment. Further, when the ratio of thickness to short axis (r3 / r2) is less than 0.7, it is close to a flat shape and is less scattered like an irregular toner, but a high transfer rate like a spherical toner cannot be obtained. In particular, when the ratio of the thickness to the short axis (r3 / r2) is 1.0, the rotating body has the long axis as the rotation axis. By adopting a spindle shape close to this, it is a shape that is neither an irregular shape, a flat shape nor a true spherical shape. Both shapes have triboelectric chargeability, dot reproducibility, transfer efficiency, splash prevention, and cleaning properties The shape satisfies all.
Note that r1, r2, and r3 were measured with a scanning electron microscope (SEM) while changing the angle of field of view and taking pictures.
[0079]
FIG. 2 shows a schematic diagram of an example of a fixing device in the image forming apparatus of the present invention. In this figure, 1 is a fixing roller, 2 is a pressure roller, 3 is a metal cylinder, 4 is an offset prevention layer, 5 is a heating lamp, 6 is a metal cylinder, 7 is an offset prevention layer, 8 is a heating lamp, and T is a toner. An image S represents a support (transfer paper such as paper). In the present invention, the surface pressure (roller load / contact area) applied between the two rollers is 1.5 × 10.⁵Fixing can be performed at Pa or lower.
[0080]
In the fixing device, the surface pressure (roller load / contact area) applied between the two rollers is 1.5 × 10.⁵There was no conventional fixing at Pa or lower. Conventional surface pressure is 1.5 × 10⁵If it exceeds Pa, otherwise it could not be fixed sufficiently. On the other hand, the toner of the present invention can be fixed even at a low temperature, and the surface pressure is 1.5 × 10.⁵Fixing is possible even at a low surface pressure of Pa or less. Further, since the surface pressure is reduced, the toner image on the transfer medium is not crushed and disturbed, so that high-definition image output is possible.
[0081]
As the fixing device, as shown in FIG. 3, a so-called surf fixing device that rotates and fixes a fixing film can also be used. In detail, the fixing film is an endless belt-like heat-resistant film, and is fixed and supported by a driving roller, a driven roller, and a heater support provided below the rollers, which are support rotating members of the film. The heating body is arranged in a suspended manner.
[0082]
The driven roller also serves as a tension roller for the fixing film, and the fixing film is rotationally driven in the clockwise direction by the rotational driving of the driving roller in the clockwise direction in the drawing. This rotational driving speed is adjusted to a speed at which the transfer material and the fixing film are equal in the fixing nip region L where the pressure roller and the fixing film are in contact with each other.
Here, the pressure roller is a roller having a rubber elastic layer having good releasability, such as silicon rubber, and a contact pressure of 4 to 10 kg of total pressure against the fixing nip region L while rotating counterclockwise. With pressure contact.
[0083]
The fixing film preferably has excellent heat resistance, releasability and durability, and a thin film having a total thickness of 100 μm or less, preferably 40 μm or less is used. For example, at least an image of a single layer film or a composite layer film of a heat resistant resin such as polyimide, polyetherimide, PES (polyether sulfide), PFA (tetrafluoroethylene bar fluoroalkyl vinyl ether copolymer resin), or a 20 μm thick film. The contact surface is coated with a release coating layer made of PTFE (tetrafluoroethylene resin), PFA or other fluororesin with a conductive material added to a thickness of 10 μm, or an elastic layer such as fluororubber or silicon rubber. It is what.
[0084]
In FIG. 3, the heating body of the present embodiment is composed of a flat substrate and a fixing heater, and the flat substrate is made of a material having high thermal conductivity and high electrical resistivity, such as alumina, and is in contact with the fixing film. Has a fixing heater formed of a resistance heating element in the longitudinal direction. Such a fixing heater is, for example, Ag / Pd, Ta₂An electric resistance material such as N is applied in a linear or belt shape by screen printing or the like. In addition, electrodes (not shown) are formed at both ends of the fixing heater, and the resistance heating element generates heat when energized between the electrodes. Furthermore, a fixing temperature sensor constituted by a thermistor is provided on the surface of the substrate opposite to the surface provided with the fixing heater.
The temperature information of the substrate detected by the fixing temperature sensor is sent to a control unit (not shown), and the amount of electric power supplied to the fixing heater is controlled by the control unit, and the heating body is controlled to a predetermined temperature.
By using such a fixing device, it is possible to efficiently shorten the rise time.
[0085]
As the electrophotographic photoreceptor used in the image forming apparatus of the present invention, a conductive support is heated to 50 ° C. to 400 ° C., and a vacuum deposition method, a sputtering method, an ion plating method, thermal CVD is applied on the support. An amorphous silicon photoconductor (hereinafter referred to as “a-Si-based photoconductor”) having a photoconductive layer made of a-Si can be used by a film forming method such as a CVD method, a photo CVD method, or a plasma CVD method. Among them, a plasma CVD method, that is, a method in which a source gas is decomposed by direct current, high frequency or microwave glow discharge to form an a-Si deposited film on a support is preferably used.
[0086]
The layer structure of the amorphous silicon photoconductor is, for example, as follows. FIG. 4 is a schematic configuration diagram for explaining a layer configuration. An electrophotographic photoreceptor 500 shown in FIG. 4A is provided with a photoconductive layer 502 made of a-Si: H, X (X represents a halogen element) and having photoconductivity on a support 501. ing. An electrophotographic photoreceptor 500 shown in FIG. 4B includes a photoconductive layer 502 made of a-Si: H, X and having photoconductivity on a support 501, and an amorphous silicon surface layer 503. It is configured. An electrophotographic photoreceptor 500 shown in FIG. 4C has a photoconductive layer 502 made of a-Si: H, X and having photoconductivity on a support 501; an amorphous silicon surface layer 503; And an amorphous silicon based charge injection blocking layer 504. In an electrophotographic photoreceptor 500 shown in FIG. 4D, a photoconductive layer 502 is provided on a support 501. The photoconductive layer 502 includes a charge generation layer 505 made of a-Si: H, X and a charge transport layer 506, and an amorphous silicon-based surface layer 503 is provided thereon.
[0087]
The support for the photoreceptor may be conductive or electrically insulating. Examples of the conductive support include metals such as Al, Cr, Mo, Au, In, Nb, Te, V, Ti, Pt, Pd, and Fe, and alloys thereof such as stainless steel. Also, at least the surface on the side where the photosensitive layer is to be formed of an electrically insulating support such as polyester, polyethylene, polycarbonate, cellulose acetate, polypropylene, polyvinyl chloride, polystyrene, polyamide or other synthetic resin film or sheet, glass or ceramic. A conductively treated support can also be used.
The shape of the support can be a cylindrical or plate-like or endless belt with a smooth or uneven surface, and the thickness thereof is appropriately determined so that a desired photoreceptor for an image forming apparatus can be formed. When flexibility as a photoreceptor for an image forming apparatus is required, it can be made as thin as possible within a range where the function as a support can be sufficiently exhibited. However, the support is usually 10 μm or more from the viewpoints of manufacturing and handling, such as mechanical strength.
[0088]
In the amorphous silicon photoconductor that can be used in the present invention, a charge injection blocking layer that functions to block charge injection from the conductive support side is provided between the conductive support and the photoconductive layer as necessary. It is more effective to provide this (FIG. 4C). That is, the charge injection blocking layer has a function of blocking charge injection from the support side to the photoconductive layer side when the photosensitive layer is subjected to a charging process with a certain polarity on its free surface. When charged, it has a so-called polarity dependency that does not exhibit such a function. In order to provide such a function, the charge injection blocking layer contains a relatively large number of atoms for controlling conductivity as compared with the photoconductive layer.
The layer thickness of the charge injection blocking layer is preferably from 0.1 to 5 μm, more preferably from 0.3 to 4 μm, and most preferably from 0.5 to 0.5 in view of obtaining desired electrophotographic characteristics and economic effects. It is desirable to be 3 μm.
[0089]
The photoconductive layer is formed on the undercoat layer as required, and the layer thickness of the photoconductive layer is appropriately determined as desired from the viewpoints of obtaining desired electrophotographic characteristics and economic effects, and preferably 1 It is desirable that the thickness is ˜100 μm, more preferably 20 to 50 μm, and most preferably 23 to 45 μm.
[0090]
The charge transport layer is a layer mainly having a function of transporting charges when the photoconductive layer is functionally separated. The charge transport layer includes at least silicon atoms, carbon atoms, and fluorine atoms as constituent elements, and is formed of a-SiC (H, F, O) including hydrogen atoms and oxygen atoms as required. It has conductive properties, in particular charge retention properties, charge generation properties and charge transport properties. In the present invention, it is particularly preferable to contain an oxygen atom.
The layer thickness of the charge transport layer is appropriately determined as desired from the viewpoint of obtaining desired electrophotographic characteristics and economic effects. The charge transport layer is preferably 5 to 50 μm, more preferably 10 to 40 μm, Optimally, the thickness is desirably 20 to 30 μm.
[0091]
The charge generation layer is a layer mainly having a function of generating charges when the photoconductive layer is functionally separated. This charge generation layer is composed of a-Si: H containing at least silicon atoms as components and substantially no carbon atoms and, if necessary, hydrogen atoms, and has desired photoconductive properties, particularly charge generation properties. Have charge transport properties.
The layer thickness of the charge generation layer is appropriately determined as desired from the viewpoint of obtaining desired electrophotographic characteristics and economic effects, etc., preferably 0.5 to 15 μm, more preferably 1 to 10 μm, optimally 1 ˜5 μm.
[0092]
If necessary, the amorphous silicon photoreceptor that can be used in the present invention can be provided with a surface layer on the photoconductive layer formed on the support as described above. It is preferable to form a surface layer. This surface layer has a free surface, and is provided to achieve the object of the present invention mainly in moisture resistance, continuous repeated use characteristics, electrical pressure resistance, use environment characteristics, and durability.
The thickness of the surface layer in the present invention is usually 0.01 to 3 μm, preferably 0.05 to 2 μm, and most preferably 0.1 to 1 μm. If the layer thickness is less than 0.01 μm, the surface layer is lost due to wear or the like during use of the photoreceptor, and if it exceeds 3 μm, electrophotographic characteristics such as an increase in residual potential are observed.
[0093]
An image forming apparatus that applies an alternating electric field when developing a latent image on a photoreceptor using the toner of the present invention can be used. In the developing device according to the embodiment of the present invention shown in FIG. 5, during development, a vibration bias voltage obtained by superimposing an AC voltage on a DC voltage is applied to the developing sleeve as a developing bias by a power source. The background portion potential and the image portion potential are located between the maximum value and the minimum value of the vibration bias potential. As a result, an alternating electric field whose direction changes alternately is formed in the developing portion. In this alternating electric field, the developer toner and carrier vibrate vigorously, and the toner flies off the electrostatic binding force on the developing sleeve and carrier and flies to the photosensitive drum, and adheres corresponding to the latent image on the photosensitive drum. To do.
[0094]
The difference (maximum peak voltage) between the maximum value and the minimum value of the vibration bias voltage is preferably 0.5 to 5 kV, and the frequency is preferably 1 to 10 kHz. As the waveform of the vibration bias voltage, a rectangular wave, a sine wave, a triangular wave or the like can be used. As described above, the DC voltage component of the vibration bias is a value between the background part potential and the image part potential, but the value closer to the background part potential than the image part potential is more likely to cover the background part potential region. This is preferable for preventing toner adhesion.
[0095]
When the vibration bias voltage waveform is a rectangular wave, the duty ratio is preferably 50% or less. Here, the duty ratio is a ratio of time during which the toner is directed to the photosensitive member during one period of the vibration bias. By doing so, the difference between the peak value at which the toner is directed to the photoreceptor and the time average value of the bias can be increased, so that the movement of the toner is further activated and the potential of the latent image surface is increased. It can adhere to the distribution and improve the roughness and resolution. In addition, since the difference between the peak value of the carrier having a charge opposite to that of the toner and the time average value of the bias toward the photosensitive member can be reduced, the movement of the carrier is reduced, and the background portion of the latent image is reduced. The probability of carriers adhering to the substrate can be greatly reduced.
[0096]
FIG. 6 shows a schematic configuration of an example of an image forming apparatus using a contact-type charging device. A photoreceptor to be charged and an image carrier is driven to rotate at a predetermined speed (process speed) in the direction of the arrow. The charging roller, which is a charging member brought into contact with the photosensitive drum, basically includes a cored bar and a conductive rubber layer formed on the roller concentrically and integrally with the outer periphery of the cored bar. In addition, the charging roller is pressed against the photosensitive drum with a predetermined pressure by a pressing means (not shown), and in this case, the charging roller rotates following the rotation of the photosensitive drum. . The charging roller is formed to have a diameter of 16 mm by coating a medium resistance rubber layer of about 100,000 Ω · cm on a core metal having a diameter of 9 mm.
The cored bar of the charging roller and the illustrated power source are electrically connected, and a predetermined bias is applied to the charging roller by the power source. As a result, the peripheral surface of the photoreceptor is uniformly charged to a predetermined polarity and potential.
[0097]
The shape of the charging member used in the present invention may take any form such as a magnetic brush or a fur brush in addition to the roller, and can be selected according to the specifications and form of the electrophotographic apparatus. In the case of using a magnetic brush, the magnetic brush is composed of various ferrite particles such as Zn—Cu ferrite as a charging member, a non-magnetic conductive sleeve for supporting it, and a magnet roll included therein. In addition, when using a fur brush, for example, as a material of the fur brush, a fur treated with carbon, copper sulfide, metal, and metal oxide is used, and this is wound around a metal or other conductive core metal. By charging or pasting, it becomes a charger.
[0098]
FIG. 7 shows a schematic configuration of an image forming apparatus having a process cartridge for supporting the developing means for holding the toner of the present invention.
In the present invention, a plurality of components such as a photoconductor, a developing unit, a charging unit, and a cleaning unit are integrally combined as a process cartridge, and this process cartridge is connected to a copying machine, The image forming apparatus main body such as a printer is configured to be detachable.
[0099]
【Example】
EXAMPLES The present invention will be further described below with reference to examples, but the present invention is not limited thereto. Hereinafter, a part shows a weight part.
[0100]
Production Example 1 (Synthesis of organic fine particle emulsion)
In a reaction vessel in which a stir bar and a thermometer were set, 683 parts of water, 11 parts of sodium salt of ethylene oxide methacrylate adduct sulfate (Eleminol RS-30: manufactured by Sanyo Chemical Industries), 138 parts of styrene, 138 parts of methacrylic acid, When 1 part of ammonium persulfate was charged and stirred at 400 rpm for 15 minutes, a white emulsion was obtained. The system was heated to raise the system temperature to 75 ° C. and reacted for 5 hours. Further, 30 parts of a 1% ammonium persulfate aqueous solution was added, and the mixture was aged at 75 ° C. for 5 hours, and an aqueous dispersion of a vinyl resin (a copolymer of styrene-methacrylic acid-methacrylic acid ethylene oxide adduct sulfate sodium salt) [fine particles Dispersion 1] was obtained.
The average particle diameter of the [fine particle dispersion 1] measured by a laser diffraction / scattering particle size distribution measuring apparatus “LA-920” (manufactured by Horiba, Ltd.) was 0.14 μm. A portion of [Fine Particle Dispersion 1] was dried to isolate the resin component. The resin content Tg was 152 ° C.
[0101]
Production Example 2 (Preparation of aqueous phase)
990 parts of water, 83 parts of [fine particle dispersion 1], 37 parts of 48.5% aqueous solution of sodium dodecyl diphenyl ether disulfonate (Eleminol MON-7: manufactured by Sanyo Chemical Industries) and 90 parts of ethyl acetate were mixed and stirred to give a milky white liquid. Got. This is designated as [Aqueous Phase 1].
[0102]
Production Example 3 (Synthesis of low molecular weight polyester)
In a reaction vessel equipped with a condenser, a stirrer and a nitrogen inlet tube, 220 parts of bisphenol A ethylene oxide 2-mole adduct, 561 parts of bisphenol A propylene oxide 3-mole adduct, 218 parts of terephthalic acid, 48 parts of adipic acid and dibutyltin 2 parts of oxide was added, reacted at 230 ° C. for 8 hours at normal pressure, and further reacted for 5 hours at a reduced pressure of 10 to 15 mmHg. Then, 45 parts of trimellitic anhydride was placed in the reaction vessel, and 180 hours at 2 hours at normal pressure. The reaction yielded [low molecular weight polyester 1]. [Low molecular polyester 1] had a number average molecular weight of 2500, a weight average molecular weight of 6700, a Tg of 43 ° C., and an acid value of 25.
[0103]
Production Example 4 (Synthesis of Intermediate Polyester)
In a reaction vessel equipped with a condenser, a stirrer, and a nitrogen introduction pipe, 682 parts of bisphenol A ethylene oxide 2-mole adduct, 81 parts of bisphenol A propylene oxide 2-mole adduct, 283 parts of terephthalic acid, 22 parts of trimellitic anhydride and 2 parts of dibutyltin oxide was added, reacted at 230 ° C. at normal pressure for 8 hours, and further reacted for 5 hours at a reduced pressure of 10 to 15 mmHg to obtain [Intermediate Polyester 1]. [Intermediate Polyester 1] had a number average molecular weight of 2,100, a weight average molecular weight of 9,500, Tg of 55 ° C., an acid value of 0.5, and a hydroxyl value of 49.
Next, 411 parts of [Intermediate polyester 1], 89 parts of isophorone diisocyanate, and 500 parts of ethyl acetate are placed in a reaction vessel equipped with a cooling tube, a stirrer and a nitrogen introduction tube, and reacted at 100 ° C. for 5 hours. 1] was obtained. The isocyanate group content of [Prepolymer 1] was 1.53%.
[0104]
Production Example 5 (Synthesis of ketimine)
In a reaction vessel equipped with a stirrer and a thermometer, 170 parts of isophoronediamine and 75 parts of methyl ethyl ketone were charged and reacted at 50 ° C. for 5 hours to obtain [ketimine compound 1]. H of [ketimine compound 1]₂The amino group content measured after reacting with O was 35.0%.
[0105]
Production Example 6 (Synthesis of master batch)
Add 1200 parts of water, 540 parts of carbon black (Printex35, manufactured by Dexa) [DBP oil absorption = 42 ml / 100 mg, pH = 9.5], 1200 parts of polyester resin, mix with a pressure kneader, and mix the two rolls. The mixture was kneaded at 150 ° C. for 30 minutes, then rolled and cooled, and pulverized with a pulverizer to obtain [Masterbatch 1].
[0106]
Production Example 7 (Production of oil phase)
378 parts of [Low molecular polyester 1], 110 parts of carnauba wax, and 947 parts of ethyl acetate were charged in a container equipped with a stirring bar and a thermometer, heated to 80 ° C. with stirring, and held at 80 ° C. for 5 hours. It was cooled to 30 ° C at 1 hour. Next, 500 parts of [Masterbatch 1] and 500 parts of ethyl acetate were charged in a container and mixed for 1 hour to obtain [Raw material solution 1].
[Raw material solution 1] 1324 parts were transferred to a container, and using a bead mill (Ultra Visco Mill, manufactured by Imex Co., Ltd.), a liquid feeding speed of 1 kg / hr, a disk peripheral speed of 6 m / sec, and 0.5 mm zirconia beads were 80% by volume. Carbon black and wax were dispersed under conditions of filling and 3 passes. Next, 1324 parts of a 65% ethyl acetate solution of [low molecular weight polyester 1] was added, followed by one pass with a bead mill under the above conditions to obtain [Pigment / Wax Dispersion 1]. The solid content concentration of [Pigment / Wax Dispersion 1] (130 ° C., 30 minutes) was 50%.
[0107]
Example 1
(Emulsification ⇒ Solvent removal)
[Pigment / Wax Dispersion 1] 648 parts, [Prepolymer 1] 154 parts, [Ketimine Compound 1] 6.6 parts in a container, TK homomixer (manufactured by Tokushu Kika) at 5,000 rpm for 1 minute After mixing, 1200 parts of [Aqueous phase 1] was added to the container, and mixed with a TK homomixer at 13,000 rpm for 20 minutes to obtain [Emulsion slurry 1].
[Emulsion slurry 1] was put into a container equipped with a stirrer and a thermometer, and after removing the solvent at 30 ° C. for 8 hours, aging was carried out at 45 ° C. for 4 hours to obtain [Dispersion slurry 1]. [Dispersion Slurry 1] had a volume average particle size of 6.02 μm and a number average particle size of 5.57 μm (measured with Multisizer II).
[0108]
(Washing ⇒ drying)
[Emulsified slurry 1] After 100 parts of vacuum filtration, it was washed as follows.
{Circle around (1)} 100 parts of ion-exchanged water was added to the filter cake, mixed with a TK homomixer (rotation speed: 12,000 rpm for 10 minutes), and then filtered.
(2): 100 parts of a 10% aqueous sodium hydroxide solution was added to the filter cake of (1), mixed with a TK homomixer (30 minutes at 12,000 rpm), and then filtered under reduced pressure. This alkali cleaning was performed again.
(3): 100 parts of 10% hydrochloric acid was added to the filter cake of (2), mixed with a TK homomixer (10 minutes at 12,000 rpm), and then filtered.
(4): Add 300 parts of deionized water to the filter cake of (3), mix with a TK homomixer (10 minutes at 12,000 rpm), and filter twice to obtain [Filter cake 1]. It was.
[Filter cake 1] was dried with a circulating dryer at 45 ° C. for 48 hours, and sieved toner base particles were obtained with an opening of 75 μm mesh.
[0109]
Next, 100 parts of the obtained base particles and 0.25 part of the charge control agent (Orient Chemical Co., Ltd., Bontron E-84) are charged into a Q-type mixer (Mitsui Mining Co., Ltd.), and the peripheral speed of the turbine blades is adjusted to 50 m. The mixing process was set to / sec. In this case, the mixing operation was performed for 2 minutes, 5 cycles of 1 minute pause, and the total treatment time was 10 minutes.
Further, 0.5 part of hydrophobic silica (H2000, manufactured by Clariant Japan) was added and mixed. In this case, the mixing operation was performed at a peripheral speed of 15 m / sec and 30 seconds of mixing for 1 minute and resting for 5 cycles.
As described above, a toner a having a volume average particle diameter Dv of 6.05 μm, a number average particle diameter of Dn 5.57 μm, Dv / Dn 1.09 (measured with Multisizer II), and CPR270 toner a was obtained.
[0110]
Example 2
Example 1 except that 6.6 parts (isocyanate group: amino group = 100: 96) of [ketimine compound 1] in Example 1 were changed to 6.4 parts (isocyanate group: amino group = 100: 93.5). In the same manner as in Example 1, a CPR180 toner b having a volume average particle diameter Dv of 5.84 μm, a number average particle diameter Dn of 5.31 μm, Dv / Dn = 1.11 (measured with Multisizer II) was obtained.
[0111]
Example 3
Except that 6.6 parts (isocyanate group: amino group = 100: 96) of [ketimine compound 1] in Example 1 were changed to 6.2 parts (isocyanate group: amino group = 100: 90), Similarly, a toner c having a volume average particle diameter Dv of 5.55 μm, a number average particle diameter of Dn of 4.89 μm, Dv / Dn = 1.14 (measured by Multisizer II), and CPR0 was obtained.
[0112]
Comparative Example 1
Example 1 is the same as Example 1 except that 6.6 parts (isocyanate group: amino group = 100: 96) of [ketimine compound 1] in Example 1 are changed to 6.7 parts (isocyanate group: amino group = 100: 97). Similarly, a toner d having a volume average particle diameter Dv of 6.11 μm, a number average particle diameter Dn of 5.61 μm, Dv / Dn = 1.09 (measured with Multisizer II), and CPR0330 toner d was obtained.
[0113]
Comparative Example 2
Example 1 and Example 1 except that 6.6 parts (isocyanate group: amino group = 100: 96) of [ketimine compound 1] in Example 1 were changed to 6.9 parts (isocyanate group: amino group = 100: 100). Similarly, a toner e of volume average particle diameter Dv 6.11 μm, number average particle diameter Dn 5.61 μm, Dv / Dn 1.09 (measured with Multisizer II), and CPR450 toner e was obtained.
[0114]
Carrier production example
100 parts of silicone resin (organostraight silicone)
100 parts of toluene
γ- (2-Aminoethyl) aminopropyltrimethoxysilane 5 parts
10 parts of carbon black
The above mixture was dispersed with a homomixer for 20 minutes to prepare a coating layer forming solution. This coat layer forming liquid was coated on the surface of 1000 parts of spherical magnetite having a particle diameter of 50 μm using a fluidized bed type coating apparatus to obtain a magnetic carrier A.
[0115]
The toner a to e4 parts were mixed with 96 parts of the magnetic carrier A by a ball mill to prepare two-component developers 1 to 5, and the following evaluation was performed. The evaluation results are shown in Table 1.
[0116]
(Skin dirt (fogging), image density evaluation, cleanability)
The above evaluation was performed using the above developer in the Ricoh Co., Ltd. immagio NEO450, which has a cleaning blade and a charging roller in contact with the photoreceptor, and has a mechanism for collecting and recycling untransferred toner at the cleaning unit. After copying 100,000 sheets of A4 horizontal chart (image pattern A) in which black solid and white solid are repeated at intervals of 1 cm in the direction perpendicular to the rotation direction of the developing sleeve, the predetermined image shown below is output. Image evaluation was performed using the criteria.
[0117]
Dirt (cover)
The blank image was stopped during development, the developer on the developed photoreceptor was tape transferred, and the difference from the image density of the untransferred tape was measured with a 938 spectrocytometer (X-Rite).
[0118]
Image density evaluation
One black solid checker image of 1 cm × 1 cm on the side of A4 was output, and the image density was measured by X-Rite (manufactured by X-Rite). This was measured at five points to obtain an average.
[0119]
Cleaning performance evaluation
The transfer residual toner on the photosensitive member that has passed the cleaning process is transferred to a white paper with a scotch tape (manufactured by Sumitomo 3M Co., Ltd.), measured with a Macbeth reflection densitometer RD514, and the difference from the blank is 0.01 or less. A product was evaluated as ○ (good), and a product exceeding it was evaluated as × (defect).
[0120]
(Fixability (fixing lower limit temperature))
Using a device in which the fixing unit of the Ricoh Co., Ltd. imagemageoNEO450 was modified as a fixing roller, type 6200 paper made by Ricoh was set on this and a copying test was performed. The fixing roll temperature at which the residual ratio of the image density after rubbing the fixed image with a pad becomes 70% or more was defined as the minimum fixing temperature.
The metal cylinder of the fixing roller was made of Fe material with a thickness of 0.34 mm. The surface pressure is 1.0 × 10⁵Pa was set.
[0121]
[Table 1]

[0122]
【The invention's effect】
The toner for developing an electrostatic charge image of the present invention is capable of forming a high-quality toner image that is free from fogging over a long period of time and has excellent low-temperature fixability, particularly in an image forming apparatus having a recycling mechanism.
[Brief description of the drawings]
FIG. 1 is a diagram illustrating a spindle-shaped toner of the present invention.
FIG. 2 is a schematic view of an example of a fixing device in the image forming apparatus of the present invention.
FIG. 3 is a schematic diagram of another example of a fixing device in the image forming apparatus of the present invention.
FIG. 4 is a schematic configuration diagram for explaining a layer configuration of an amorphous silicon photoconductor used in the present invention.
FIG. 5 is a schematic diagram of an example of a developing device of an image forming apparatus that applies an alternating electric field according to the present invention.
FIG. 6 is a schematic configuration diagram of an example of an image forming apparatus using a contact-type charging device.
FIG. 7 is a schematic configuration of an image forming apparatus having a process cartridge of the present invention.
[Explanation of sign]
1 Fixing roller
2 Pressure roller
3, 6 Metal cylinder
4, 7 Offset prevention layer
5, 8 Heating lamp
T Toner image
S Support (transfer paper)
500 photoconductor
501 Support
502 Photoconductive layer
503 Amorphous silicon surface layer
504 Amorphous silicon charge injection blocking layer
505 Charge generation layer
506 Charge transport layer

Claims (14)

  At least a dissolved or dispersed product formed by dissolving or dispersing a modified polyester resin capable of reacting with a compound having an active hydrogen group, a colorant, and a release agent in an organic solvent in an aqueous medium containing resin fine particles. Obtained by dispersing and reacting with a compound having an active hydrogen group as a crosslinking agent and / or an extender, removing the organic solvent from the obtained dispersion, and washing and desorbing resin fine particles adhering to the toner surface. A toner for developing an electrostatic charge image, wherein in the toner containing at least a toner binder, a colorant, and a release agent, the CPR representing the amount of a basic substance of the toner is 300 or less.   2. The electrostatic image developing toner according to claim 1, wherein the modified polyester resin contains a prepolymer having at least an isocyanate group.   The electrostatic image developing toner according to claim 1, wherein the compound having an active hydrogen group is an amine.   The toner binder is composed of a modified polyester and an unmodified polyester, and the weight ratio of the modified polyester to the unmodified polyester is 5/95 to 80/20. The toner for developing an electrostatic image according to any one of the above.   The electrostatic charge image developing toner according to claim 1, wherein the toner binder has an acid value of 1 to 30 mg KOH / g.   6. The electrostatic charge image development according to claim 1, wherein the resin fine particles are made of at least one resin selected from vinyl resins, polyurethane resins, epoxy resins, and polyester resins. Toner. A developer for developing a two-component electrostatic image comprising the toner for developing an electrostatic image according to any one of claims 1 to 6 and a carrier. In the image forming apparatus having a toner recycling mechanism, an image forming apparatus which comprises using a toner according to any one of claims 1-6. In an image forming apparatus in which a toner image on a transfer material is fixed by heating and melting by passing between two rollers, a surface pressure (roller load / contact area) applied between the two rollers is 1.5. An image forming apparatus for fixing at × 10 ⁵ Pa or less, wherein the toner for developing an electrostatic charge image according to any one of claims 1 to 6 is used. An image forming apparatus for forming an image using the electrostatic image developing toner according to any one of claims 1 to 6 , wherein the fixing device for fixing the toner includes a heating body having a heating element, A film having a film in contact with the heating body and a pressure member in pressure contact with the heating body through the film, and a recording material on which an unfixed image is formed is passed between the film and the pressure member to heat and fix An image forming apparatus characterized by being a fixing device. An image forming apparatus for forming an image by using a toner according to any one of claims 1 to 6, the image forming apparatus, wherein the photoreceptor is an amorphous silicon photoconductor. An image forming apparatus for forming an image by using a toner according to any one of claims 1 to 6, when developing a latent image on the photoreceptor, characterized by applying an alternating electric field An image forming apparatus. An image forming apparatus that forms an image using the electrostatic image developing toner according to any one of claims 1 to 6 , wherein the charging device contacts the charging member with the latent image carrier, and the charging member An image forming apparatus that is a charging device that performs charging by applying a voltage. In a process cartridge that integrally supports at least one member selected from a photoconductor, a developing unit, a charging unit, and a cleaning unit and is detachable from the image forming apparatus main body, the developing unit holds toner, and toner, a process cartridge, wherein the claim 1 as a toner for developing an electrostatic charge image according 6.

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