JP4085590B2 - Toner for developing electrostatic image, method for producing the same, and image forming apparatus - Google Patents

Description

【００８０】
【化２】

【００８１】
上記化合物の添加量は、トナー全体に対し１〜３０質量％、好ましくは２〜２０質量％、さらに好ましくは３〜１５質量％である。
【００８２】
本発明のトナーでは、ミニエマルジョン重合法により樹脂粒子中に上記離型剤を内包させ、着色粒子とともに塩析、融着させて調製することが好ましい。
【００８３】
本発明に係るトナー粒子の物理的特性、個数平均粒径、形状係数の変動係数、個数粒度分布における個数変動係数、形状係数などについて説明する。
【００８４】
本発明のトナーの粒径は、個数平均粒径で２μｍ〜１０μｍであることが好ましく、更に好ましくは２μｍ〜８μｍである。この粒径は、トナーの製造方法において、凝集剤（塩析剤）の濃度や有機溶媒の添加量、融着時間、重合体の組成によって制御することができる。
【００８５】
個数平均粒径が３〜１０μｍに調整されることにより、定着工程において、飛翔して加熱部材に付着しオフセットを発生させる付着力の大きいトナー微粒子が少なくなり、また、転写効率が高くなってハーフトーンの画質が向上し、細線やドット等の画質を向上させることが出来る。
【００８６】
トナーの個数平均粒径は、コールターカウンターＴＡ−II、コールターマルチサイザー、ＳＬＡＤ１１００（島津製作所社製レーザー回折式粒径測定装置）等を用いて測定することができる。
【００８７】
本発明においては、コールターマルチサイザーを用い、粒度分布を出力するインターフェース（日科機社製）、パーソナルコンピューターを接続して使用した。前記コールターマルチサイザーにおけるアパーチャーとしては、１００μｍのものを用いて、２μｍ以上（例えば２〜４０μｍ）のトナーの体積分布を測定して粒度分布および平均粒径を算出した。
【００８８】
本発明のトナー粒子の形状係数について説明する。
本発明のトナーの形状係数は、下記式により示されるものであり、トナー粒子の丸さの度合いを示す。
【００８９】
形状係数＝（（最大径／２）²×π）／投影面積
ここに、最大径とは、トナー粒子の平面上への投影像を２本の平行線ではさんだとき、その平行線の間隔が最大となる粒子の幅をいう。また、投影面積とは、トナー粒子の平面上への投影像の面積をいう。
【００９０】
本発明では、この形状係数は、走査型電子顕微鏡により２０００倍にトナー粒子を拡大した写真を撮影し、ついでこの写真に基づいて「ＳＣＡＮＮＩＮＧ ＩＭＡＧＥ ＡＮＡＬＹＺＥＲ」（日本電子社製）を使用して写真画像の解析を行うことにより測定した。この際、１００個のトナー粒子を使用して本発明の形状係数を上記算出式にて測定したものである。
【００９１】
本発明に係るトナーの形状係数の変動係数について説明する。
トナーの「形状係数の変動係数」は下記式から算出される。
【００９２】
トナーの形状係数の変動係数＝（Ｓ１／Ｋ）×１００（％）
式中、Ｓ１は１００個のトナー粒子の形状係数の標準偏差を示し、Ｋは形状係数の平均値を示す。
【００９３】
本発明に係るトナーの個数粒度分布、個数変動係数について説明する。
トナーの個数粒度分布及び個数変動係数はコールターカウンターＴＡ−II或いはコールターマルチサイザー（コールター社製）で測定される。本発明においてはコールターマルチサイザーを用い、粒度分布を出力するインターフェース（日科機製）、パーソナルコンピューターを接続して使用した。
【００９４】
個数粒度分布とは、粒子径に対するトナー粒子の相対度数を表すものであり、個数平均粒径とは、個数粒度分布におけるメジアン径を表すものである。トナーの「個数粒度分布における個数変動係数」（以下トナーの個数変動係数という）は下記式から算出される。
【００９５】
トナーの個数変動係数＝（Ｓ２／Ｄｎ）×１００（％）
式中、Ｓ２は個数粒度分布における標準偏差を示し、Ｄｎは個数平均粒径（μｍ）を示す。
【００９６】
請求項６に記載のように、トナー粒子の個数平均粒径が２μｍ〜８μｍであり、形状係数の変動係数が１６％以下で、且つ、個数粒度分布における個数変動係数が２７％以下に調整されることにより、本発明のトナーは更に好ましく本発明に記載の効果を奏することが出来る。
【００９７】
形状係数の変動係数は１６％以下のトナーを用いることにより、前記形状係数の効果で記した効果がより顕著に発現されるが、更に好ましい形状係数の変動係数は１４％以下である。
【００９８】
請求項６に記載のトナーの個数変動係数は２７％以下であり、好ましくは２５％以下である。個数変動係数が２７％以下であることにより、帯電量分布がシャープとなり、転写効率が高くなって画質が向上する。このようなトナーを本発明の画像形成装置に用いると、トナーの帯電特性が安定する、クリーニング不良が発生しにくく、上述したシロキサン系樹脂層を有する感光体の表面を常にクリーンに保つことができる。
【００９９】
トナーにおける個数変動係数を制御する方法は特に限定されない。例えば、トナー粒子を風力により分級する方法も使用できるが、個数変動係数をより小さくするためには液中での分級が効果的である。この液中で分級する方法としては、遠心分離機を用い、回転数を制御してトナー粒子径の違いにより生じる沈降速度差に応じてトナー粒子を分別回収し調製する方法がある。
【０１００】
特に懸濁重合法によりトナーを製造する場合、個数粒度分布における個数変動係数を２７％以下とするためには分級操作が必須である。懸濁重合法では、重合前に重合性単量体を水系媒体中にトナーとしての所望の大きさの油滴に分散させることが必要である。即ち、重合性単量体の大きな油滴に対して、ホモミキサーやホモジナイザーなどによる機械的な剪断を繰り返して、トナー粒子程度の大きさまで油滴を小さくすることとなるが、このような機械的な剪断による方法では、得られる油滴の個数粒度分布は広いものとなり、従って、これを重合してなるトナーの粒度分布も広いものとなる。このために分級操作が必須となる。
【０１０１】
また、トナーの形状係数及び形状係数の変動係数を、極めてロットのバラツキなく均一に制御するために、本発明のトナーを構成する樹脂粒子（重合体粒子）を調製（重合）、当該樹脂粒子を融着、形状制御させる工程において、形成されつつあるトナー粒子（着色粒子）の特性をモニタリングしながら適正な工程終了時期を決めてもよい。
【０１０２】
モニタリングするとは、インラインに測定装置を組み込みその測定結果に基づいて、工程条件の制御をするという意味である。即ち、形状などの測定をインラインに組み込んで、例えば樹脂粒子を水系媒体中で会合或いは融着させることで形成する重合法トナーでは、融着などの工程で逐次サンプリングを実施しながら形状や粒径を測定し、所望の形状になった時点で反応を停止する。
【０１０３】
モニタリング方法としては、特に限定されるものではないが、フロー式粒子像分析装置ＦＰＩＡ−２０００（東亜医用電子社製）を使用することができる。本装置は試料液を通過させつつリアルタイムで画像処理を行うことで形状をモニタリングできるため好適である。即ち、反応場よりポンプなどを使用し、常時モニターし、形状などを測定することを行い、所望の形状などになった時点で反応を停止するものである。
【０１０４】
請求項７に記載のように、トナー粒子の個数平均粒径が２μｍ〜８μｍであり、且つ、形状係数が１．０〜１．６の範囲にあるトナー粒子が６５個数％以上とすることが好ましく、より好ましくは、７０個数％以上である。
【０１０５】
さらに好ましくは、請求項８に記載のように、トナー粒子の個数平均粒径が２μｍ〜８μｍであり、且つ、形状係数が１．２〜１．６の範囲にあるトナー粒子が６５個数％以上とすることであり、より好ましくは、７０個数％以上である。
【０１０６】
また、請求項１２に記載のように、形状係数が１．２〜１．６の範囲にあるトナー粒子が６５個数％以上であり、且つ、形状係数の変動係数を１６％以下に調整することによっても、現像性、細線再現性に優れ、安定したクリーニング性を長期にわたって形成することができることを見出した。
【０１０７】
形状係数については、その数値範囲が１．０〜１．６の範囲にあるトナー粒子が６５個数％以上であることにより、現像剤搬送部材などでの摩擦帯電性がより均一となり、過度に帯電したトナーの蓄積が無く、現像剤搬送部材表面よりトナーがより交換しやすくなるために、現像ゴースト等の問題も発生しにくくなる。さらに、トナー粒子が破砕しにくくなって帯電付与部材の汚染が減少し、トナーの帯電性が安定する等の効果を得ることが出来る。
【０１０８】
この形状係数を制御する方法は特に限定されない。例えばトナー粒子を熱気流中に噴霧する方法、またはトナー粒子を気相中において衝撃力による機械的エネルギーを繰り返して付与する方法、あるいはトナーを溶解しない溶媒中に添加し旋回流を付与する方法等により、形状係数を１．０〜１．６、または１．２〜１．６にしたトナーを調整し、これを通常のトナー中へ本発明の範囲内になるように添加して調整する方法がある。また、いわゆる重合法トナーを調製する段階で全体の形状を制御し、形状係数を１．０〜１．６、または１．２〜１．６に調整したトナーを同様に通常のトナーへ添加して調整する方法がある。
【０１０９】
また、本発明のトナーとしては、トナー粒子の粒径をＤ（μｍ）とするとき、自然対数ｌｎＤを横軸にとり、この横軸を０．２３間隔で複数の階級に分けた個数基準の粒度分布を示すヒストグラムにおいて、最頻階級に含まれるトナー粒子の相対度数（ｍ１）と、前記最頻階級の次に頻度の高い階級に含まれるトナー粒子の相対度数（ｍ２）との和（Ｍ）が７０％以上であるトナーであることが好ましい。
【０１１０】
相対度数（ｍ１）と相対度数（ｍ２）との和（Ｍ）が７０％以上であることにより、トナー粒子の粒度分布の分散が狭くなるので、当該トナーを画像形成工程に用いることにより選択現像の発生を確実に抑制することができる。
【０１１１】
本発明において、前記の個数基準の粒度分布を示すヒストグラムは、自然対数ｌｎＤ（Ｄ：個々のトナー粒子の粒径）を０．２３間隔で複数の階級（０〜０．２３：０．２３〜０．４６：０．４６〜０．６９：０．６９〜０．９２：０．９２〜１．１５：１．１５〜１．３８：１．３８〜１．６１：１．６１〜１．８４：１．８４〜２．０７：２．０７〜２．３０：２．３０〜２．５３：２．５３〜２．７６・・・）に分けた個数基準の粒度分布を示すヒストグラムであり、このヒストグラムは、下記の条件に従って、コールターマルチサイザーにより測定されたサンプルの粒径データを、Ｉ／Ｏユニットを介してコンピュータに転送し、当該コンピュータにおいて、粒度分布分析プログラムにより作成されたものである。
【０１１２】
〔測定条件〕
１：アパーチャー：１００μｍ
２：サンプル調製法：電解液〔ＩＳＯＴＯＮ Ｒ−１１（コールターサイエンティフィックジャパン社製）〕５０〜１００ｍｌに界面活性剤（中性洗剤）を適量加えて攪拌し、これに測定試料１０〜２０ｍｇを加える。この系を超音波分散機にて１分間分散処理することにより調製する。
【０１１３】
さらに本発明者等は、個々のトナー粒子の微小な形状に着目して検討を行った結果、現像装置内部において、トナー粒子の角部分の形状が変化して丸くなり、その部分がブレード摩耗を発生させていることが判明した。この理由については明確ではないが、角部分にはストレスが加わりやすく、この部分のブレード摩耗を促進させると推定した。又、摩擦帯電によってトナー粒子に電荷を付与する場合には、特に角部分では電荷が集中しやすくなり、トナー粒子の帯電が不均一になりやすいと推定される。
【０１１４】
即ち、角がないトナー粒子の割合を５０個数％以上とし、個数粒度分布における個数変動係数を２７％以下に制御されたトナー粒子から構成されるトナーを使用することによっても、現像性、細線再現性に優れ、高画質な画像を長期にわたって形成することができることを見出した。
【０１１５】
本発明に係る『角のないトナー粒子』について図５を用いて説明する。
本発明に係るトナーにおいては、トナーを構成するトナー粒子中、角がないトナー粒子の割合は５０個数％以上であることが好ましく、更に好ましくは、７０個数％以上である。
【０１１６】
角がないトナー粒子の割合が５０個数％以上であることにより、転写されたトナー層（粉体層）の空隙が減少して定着性が向上し、オフセットが発生しにくくなる。また、摩耗、破断しやすいトナー粒子および電荷の集中する部分を有するトナー粒子が減少することとなり、帯電量分布がシャープとなって、帯電性も安定し、良好な画質を長期にわたって形成できる。
【０１１７】
ここに、「角がないトナー粒子」とは、電荷の集中するような突部またはストレスにより摩耗しやすいような突部を実質的に有しないトナー粒子を言い、具体的には以下のトナー粒子を角がないトナー粒子という。すなわち、図５（ａ）に示すように、トナー粒子Ｔの長径をＬとするときに、半径（Ｌ／１０）の円Ｃで、トナー粒子Ｔの周囲線に対し１点で内側に接しつつ内側をころがした場合に、当該円ＣがトナーＴの外側に実質的にはみださない場合を「角がないトナー粒子」という。「実質的にはみ出さない場合」とは、はみ出す円が存在する突起が１箇所以下である場合をいう。また、「トナー粒子の長径」とは、当該トナー粒子の平面上への投影像を２本の平行線ではさんだとき、その平行線の間隔が最大となる粒子の幅をいう。なお、図５（ｂ）および（ｃ）は、それぞれ角のあるトナー粒子の投影像を示している。
【０１１８】
角がないトナー粒子の割合の測定は次のようにして行った。先ず、走査型電子顕微鏡によりトナー粒子を拡大した写真を撮影し、さらに拡大して１５，０００倍の写真像を得る。次いでこの写真像について前記の角の有無を測定する。この測定を１００個のトナー粒子について行った。
【０１１９】
角がないトナーを得る方法は特に限定されるものではない。例えば、形状係数を制御する方法として前述したように、トナー粒子を熱気流中に噴霧する方法、またはトナー粒子を気相中において衝撃力による機械的エネルギーを繰り返して付与する方法、あるいはトナーを溶解しない溶媒中に添加し、旋回流を付与することによって得ることができる。
【０１２０】
本発明のトナーの製造方法について説明する。
本発明のトナーは、懸濁重合法や、必要な添加剤の乳化液を加えた液中（水系媒体中）にて単量体を乳化重合、あるいはミニエマルション重合して微粒の樹脂粒子を調製し、本発明の荷電制御性樹脂粒子を添加し、その後に、有機溶媒、塩類などの凝集剤等を添加して当該樹脂粒子を凝集、融着する方法で製造することができる。
【０１２１】
本発明のトナーを製造する方法の一例を示せば、重合性単量体中に荷電制御性樹脂を溶解させ、着色剤や必要に応じて離型剤、さらに重合開始剤等の各種構成材料を添加し、ホモジナイザー、サンドミル、サンドグラインダー、超音波分散機などで重合性単量体に各種構成材料を溶解あるいは分散させる。この各種構成材料が溶解あるいは分散された重合性単量体を分散安定剤を含有した水系媒体中にホモミキサーやホモジナイザーなどを使用しトナーとしての所望の大きさの油滴に分散させる。その後、攪拌機構が後述の攪拌翼である反応装置（攪拌装置）へ移し、加熱することで重合反応を進行させる。反応終了後、分散安定剤を除去し、濾過、洗浄し、さらに乾燥することで本発明のトナーを調製する。なお、本発明でいうところの「水系媒体」とは、少なくとも水が５０質量％以上含有されたものを示す。
【０１２２】
また、本発明のトナーを製造する方法として樹脂粒子を水系媒体中で塩析、凝集、融着させて調製する方法も挙げることができる。この方法としては、特に限定されるものではないが、例えば、特開平５−２６５２５２号公報や特開平６−３２９９４７号公報、特開平９−１５９０４号公報に示す方法を挙げることができる。すなわち、樹脂粒子と着色剤などの構成材料の分散粒子、あるいは樹脂および着色剤等より構成される微粒子を複数以上塩析、凝集、融着させる方法、特に水中にてこれらを乳化剤を用いて分散した後に、臨界凝集濃度以上の凝集剤を加え塩析させると同時に、形成された重合体自体のガラス転移点温度以上で加熱融着させて融着粒子を形成しつつ徐々に粒径を成長させ、目的の粒径となったところで水を多量に加えて粒径成長を停止し、さらに加熱、攪拌しながら粒子表面を平滑にして形状を制御し、その粒子を含水状態のまま流動状態で加熱乾燥することにより、本発明のトナーを形成することができる。なお、ここにおいて凝集剤と同時にアルコールなど水に対して無限溶解する溶媒を加えてもよい。
【０１２３】
トナーの製造工程は、主に、以下に示す工程より構成されている。
１：離型剤が最外層以外の領域（中心部または中間層）に含有されている複合樹脂粒子を得るための多段重合工程（Ｉ）
２：複合樹脂粒子と着色剤粒子とを塩析／融着させてトナー粒子を得る塩析／融着工程（II）
３：トナー粒子の分散系から当該トナー粒子を濾別し、当該トナー粒子から界面活性剤などを除去する濾過・洗浄工程
４：洗浄処理されたトナー粒子を乾燥する乾燥工程、
５：乾燥処理されたトナー粒子に外添剤を添加する工程
から構成される。
【０１２４】
以下、各工程について、詳細に説明する。
〔多段重合工程（Ｉ）〕
多段重合工程（Ｉ）は、樹脂粒子の表面に、単量体の重合体からなる被覆層を形成する多段重合法により、複合樹脂粒子を製造する工程である。
【０１２５】
本発明においては、製造の安定性および得られるトナーの破砕強度の観点から三段重合以上の多段重合法を採用することが好ましい。
【０１２６】
以下に、多段重合法の代表例である二段重合法および三段重合法について説明する。
【０１２７】
〈二段重合法〉
二段重合法は、離型剤を含有する高分子量樹脂から形成される中心部（核）と、低分子量樹脂から形成される外層（殻）とにより構成される複合樹脂粒子を製造する方法である。
【０１２８】
この方法を具体的に説明すると、先ず、離型剤を単量体Ｌに溶解させて単量体溶液を調製し、この単量体溶液を水系媒体（例えば、界面活性剤水溶液）中に油滴分散させた後、この系を重合処理（第１段重合）することにより、離型剤を含む高分子量の樹脂粒子の分散液を調製するものである。
【０１２９】
次いで、この樹脂粒子の分散液に、重合開始剤と低分子量樹脂を得るための単量体Ｌとを添加し、樹脂粒子の存在下で単量体Ｌを重合処理（第２段重合）を行うことにより、樹脂粒子の表面に、低分子量の樹脂（単量体Ｌの重合体）からなる被覆層を形成する方法である。
【０１３０】
〈三段重合法〉
三段重合法は、高分子量樹脂から形成される中心部（核）、離型剤を含有する中間層及び低分子量樹脂から形成される外層（殻）とにより構成される複合樹脂粒子を製造する方法である。
【０１３１】
この方法を具体的に説明すると、先ず、常法に従った重合処理（第１段重合）により得られた樹脂粒子の分散液を、水系媒体（例えば、界面活性剤の水溶液）に添加するとともに、上記水系媒体中に、離型剤を単量体Ｍに溶解させてなる単量体溶液を油滴分散させた後、この系を重合処理（第２段重合）することにより、樹脂粒子（核粒子）の表面に、離型剤を含有する樹脂（単量体Ｍの重合体）からなる被覆層（中間層）を形成して、複合樹脂粒子（高分子量樹脂−中間分子量樹脂）の分散液を調製する。
【０１３２】
次いで、得られた複合樹脂粒子の分散液に、重合開始剤と低分子量樹脂を得るための単量体Ｌとを添加し、複合樹脂粒子の存在下で単量体Ｌを重合処理（第３段重合）することにより、複合樹脂粒子の表面に、低分子量の樹脂（単量体Ｌの重合体）からなる被覆層を形成する。上記方法において、第２段重合を組み入れることにより、離型剤を微細かつ均一に分散することができ好ましい。
【０１３３】
本発明に係るトナーの製造方法においては、重合性単量体を水系媒体中で重合することが１つの特徴である。すなわち、離型剤を含有する樹脂粒子（核粒子）または被覆層（中間層）を形成する際に、離型剤を単量体に溶解させ、得られる単量体溶液を水系媒体中で油滴分散させ、この系に重合開始剤を添加して重合処理することにより、ラテックス粒子として得る方法である。
【０１３４】
本発明でいう水系媒体とは、水５０〜１００質量％と水溶性の有機溶媒０〜５０質量％とからなる媒体をいう。水溶性の有機溶媒としては、例えば、メタノール、エタノール、イソプロパノール、ブタノール、アセトン、メチルエチルケトン、テトラヒドロフラン等を例示することができ、得られる樹脂を溶解しないアルコール系有機溶媒が好ましい。
【０１３５】
離型剤を含有する樹脂粒子または被覆層を形成するために好適な重合法としては、臨界ミセル濃度以下の濃度の界面活性剤を溶解してなる水系媒体中に、離型剤を単量体に溶解した単量体溶液を、機械的エネルギーを利用して油滴分散させて分散液を調製し、得られた分散液に水溶性重合開始剤を添加して、油滴内でラジカル重合させる方法（以下、本発明では「ミニエマルジョン法」という。）を挙げることができ、本発明の効果をより発揮することができ好ましい。なお、上記方法において、水溶性重合開始剤に代えて、あるいは水溶性重合開始剤と共に、油溶性重合開始剤を用いても良い。
【０１３６】
機械的に油滴を形成するミニエマルジョン法によれば、通常の乳化重合法とは異なり、油相に溶解させた離型剤が脱離することがなく、形成される樹脂粒子または被覆層内に十分な量の離型剤を導入することができる。
【０１３７】
ここで、機械的エネルギーによる油滴分散を行うための分散機としては、特に限定されるものではなく、例えば、高速回転するローターを備えた攪拌装置「クレアミックス（ＣＬＥＡＲＭＩＸ）」（エム・テクニック（株）製）、超音波分散機、機械式ホモジナイザー、マントンゴーリンおよび圧力式ホモジナイザーなどを挙げることができる。また、分散粒子径としては、１０〜１０００ｎｍとされ、好ましくは５０〜１０００ｎｍ、更に好ましくは３０〜３００ｎｍである。
【０１３８】
なお、離型剤を含有する樹脂粒子または被覆層を形成するための他の重合法として、乳化重合法、懸濁重合法、シード重合法などの公知の方法を採用することもできる。また、これらの重合法は、複合樹脂粒子を構成する樹脂粒子（核粒子）または被覆層であって、離型剤を含有しないものを得るためにも採用することができる。
【０１３９】
この重合工程（Ｉ）で得られる複合樹脂粒子の粒子径は、電気泳動光散乱光度計「ＥＬＳ−８００」（大塚電子社製）を用いて測定される重量平均粒径で１０〜１０００ｎｍの範囲にあることが好ましい。
【０１４０】
また、複合樹脂粒子のガラス転移温度（Ｔｇ）は４８〜７４℃の範囲にあることが好ましく、更に好ましくは５２〜６４℃である。
【０１４１】
また、複合樹脂粒子の軟化点は９５〜１４０℃の範囲にあることが好ましい。
〔塩析／融着工程（II）〕
この塩析／融着工程（II）は、前記多段重合工程（Ｉ）によって得られた複合樹脂粒子と着色剤粒子とを塩析／融着させる（塩析と融着とを同時に起こさせる）ことによって、不定形（非球形）のトナー粒子を得る工程である。
【０１４２】
本発明でいう塩析／融着とは、塩析（粒子の凝集）と融着（粒子間の界面消失）とが同時に起こること、または、塩析と融着とを同時に起こさせる行為をいう。塩析と融着とを同時に行わせるためには、複合樹脂粒子を構成する樹脂のガラス転移温度（Ｔｇ）以上の温度条件下において粒子（複合樹脂粒子、着色剤粒子）を凝集させる必要がある。
【０１４３】
この塩析／融着工程（II）では、複合樹脂粒子および着色剤粒子とともに、荷電制御剤などの内添剤粒子（数平均一次粒子径が１０〜１０００ｎｍ程度の微粒子）を塩析／融着させてもよい。また、着色剤粒子は、表面改質されていてもよく、表面改質剤としては、従来公知のものを使用することができる。
【０１４４】
着色剤粒子は、水性媒体中に分散された状態で塩析／融着処理が施される。着色剤粒子が分散される水性媒体は、臨界ミセル濃度（ＣＭＣ）以上の濃度で界面活性剤が溶解されている水溶液が好ましい。
【０１４５】
着色剤粒子の分散処理に使用する分散機は、特に限定されないが、好ましくは、高速回転するローターを備えた攪拌装置「クレアミックス（ＣＬＥＡＲＭＩＸ）」（エム・テクニック（株）製）、超音波分散機、機械的ホモジナイザー、マントンゴーリン、圧力式ホモジナイザー等の加圧分散機、ゲッツマンミル、ダイヤモンドファインミル等の媒体型分散機が挙げられる。
【０１４６】
複合樹脂粒子と着色剤粒子とを塩析／融着させるためには、複合樹脂粒子および着色剤粒子が分散している分散液中に、臨界凝集濃度以上の塩析剤（凝集剤）を添加するとともに、この分散液を、複合樹脂粒子のガラス転移温度（Ｔｇ）以上に加熱することが必要である。
【０１４７】
塩析／融着させるために好適な温度範囲としては、（Ｔｇ＋１０）〜（Ｔｇ＋５０℃）とされ、特に好ましくは（Ｔｇ＋１５）〜（Ｔｇ＋４０℃）とされる。また、融着を効果的に行なわせるために、水に無限溶解する有機溶媒を添加してもよい。
【０１４８】
〔濾過・洗浄工程〕
この濾過・洗浄工程では、上記の工程で得られたトナー粒子の分散系から当該トナー粒子を濾別する濾過処理と、濾別されたトナー粒子（ケーキ状の集合物）から界面活性剤や塩析剤などの付着物を除去する洗浄処理とが施される。
【０１４９】
ここに、濾過処理方法としては、遠心分離法、ヌッチェ等を使用して行う減圧濾過法、フィルタープレス等を使用して行う濾過法など特に限定されない。
【０１５０】
〔乾燥工程〕
この工程は、洗浄処理されたトナー粒子を乾燥処理する工程である。
【０１５１】
この工程で使用される乾燥機としては、スプレードライヤー、真空凍結乾燥機、減圧乾燥機などを挙げることができ、静置棚乾燥機、移動式棚乾燥機、流動層乾燥機、回転式乾燥機、攪拌式乾燥機などを使用することが好ましい。
【０１５２】
乾燥処理されたトナー粒子の水分は、５質量％以下であることが好ましく、更に好ましくは２質量％以下である。
【０１５３】
また、本発明に係る静電荷像現像用トナーを製造するに当たり、上記のように水系媒体中にて粒子を形成し、該粒子を乾燥後に、本発明に係る脂肪酸リチウム塩を０．００５質量％〜０．３質量％の範囲で外部添加し、トナー粒子が製造される。
【０１５４】
なお、乾燥処理されたトナー粒子同士が、弱い粒子間引力で凝集している場合には、当該凝集体を解砕処理してもよい。ここに、解砕処理装置としては、ジェットミル、ヘンシェルミキサー、コーヒーミル、フードプロセッサー等の機械式の解砕装置を使用することができる。
【０１５５】
本発明のトナーは、着色剤の不存在下において複合樹脂粒子を形成し、当該複合樹脂粒子の分散液に着色剤粒子の分散液を加え、当該複合樹脂粒子と着色剤粒子とを塩析／融着させることにより調製されることが好ましい。
【０１５６】
このように、複合樹脂粒子の調製を着色剤の存在しない系で行うことにより、複合樹脂粒子を得るための重合反応が阻害されることない。このため、本発明のトナーによれば、優れた耐オフセット性が損なわれることはなく、トナーの蓄積による定着装置の汚染や画像汚れを発生させることはない。
【０１５７】
また、複合樹脂粒子を得るための重合反応が確実に行われる結果、得られるトナー粒子中に単量体やオリゴマーが残留するようなことはなく、当該トナーを使用する画像形成装置の熱定着工程において、異臭を発生させることはない。
【０１５８】
さらに、得られるトナー粒子の表面特性は均質であり、帯電量分布もシャープとなるため、鮮鋭性に優れた画像を長期にわたり形成することができる。このようなトナー粒子間における組成・分子量・表面特性が均質であるトナーによれば、接触加熱方式による定着工程を含む画像形成装置において、画像支持体に対する良好な接着性（高い定着強度）を維持しながら、耐オフセット性および巻き付き防止特性の向上を図ることができ、適度の光沢を有する画像を得ることができる。
【０１５９】
次に、トナー製造工程で用いられる各構成因子について、詳細に説明する。
（重合性単量体）
本発明に用いられる樹脂（バインダー）を造るための重合性単量体としては、疎水性単量体を必須の構成成分とし、必要に応じて架橋性単量体が用いられる。また、下記するごとく酸性極性基を有する単量体又は塩基性極性基を有するモノマーを少なくとも１種類含有するのが望ましい。
【０１６０】
（１）疎水性単量体
単量体成分を構成する疎水性単量体としては、特に限定されるものではなく従来公知の単量体を用いることができる。また、要求される特性を満たすように、１種または２種以上のものを組み合わせて用いることができる。
【０１６１】
具体的には、モノビニル芳香族系単量体、（メタ）アクリル酸エステル系単量体、ビニルエステル系単量体、ビニルエーテル系単量体、モノオレフィン系単量体、ジオレフィン系単量体、ハロゲン化オレフィン系単量体等を用いることができる。
【０１６２】
ビニル芳香族系単量体としては、例えば、スチレン、ｏ−メチルスチレン、ｍ−メチルスチレン、ｐ−メチルスチレン、ｐ−メトキシスチレン、ｐ−フェニルスチレン、ｐ−クロロスチレン、ｐ−エチルスチレン、ｐ−ｎ−ブチルスチレン、ｐ−ｔｅｒｔ−ブチルスチレン、ｐ−ｎ−ヘキシルスチレン、ｐ−ｎ−オクチルスチレン、ｐ−ｎ−ノニルスチレン、ｐ−ｎ−デシルスチレン、ｐ−ｎ−ドデシルスチレン、２，４−ジメチルスチレン、３，４−ジクロロスチレン等のスチレン系単量体およびその誘導体が挙げられる。
【０１６３】
アクリル系単量体としては、アクリル酸、メタクリル酸、アクリル酸メチル、アクリル酸エチル、アクリル酸ブチル、アクリル酸−２−エチルヘキシル、アクリル酸シクロヘキシル、アクリル酸フェニル、メタクリル酸メチル、メタクリル酸エチル、メタクリル酸ブチル、メタクリル酸ヘキシル、メタクリル酸−２−エチルヘキシル、β−ヒドロキシアクリル酸エチル、γ−アミノアクリル酸プロピル、メタクリル酸ステアリル、メタクリル酸ジメチルアミノエチル、メタクリル酸ジエチルアミノエチル等が挙げられる。
【０１６４】
ビニルエステル系単量体としては、酢酸ビニル、プロピオン酸ビニル、ベンゾエ酸ビニル等が挙げられる。
【０１６５】
ビニルエーテル系単量体としては、ビニルメチルエーテル、ビニルエチルエーテル、ビニルイソブチルエーテル、ビニルフェニルエーテル等が挙げられる。
【０１６６】
モノオレフィン系単量体としては、エチレン、プロピレン、イソブチレン、１−ブテン、１−ペンテン、４−メチル−１−ペンテン等が挙げられる。
【０１６７】
ジオレフィン系単量体としては、ブタジエン、イソプレン、クロロプレン等が挙げられる。
【０１６８】
（２）架橋性単量体
樹脂粒子の特性を改良するために架橋性単量体を添加しても良い。架橋性単量体としては、例えば、ジビニルベンゼン、ジビニルナフタレン、ジビニルエーテル、ジエチレングリコールメタクリレート、エチレングリコールジメタクリレート、ポリエチレングリコールジメタクリレート、フタル酸ジアリル等の不飽和結合を２個以上有するものが挙げられる。
【０１６９】
（３）酸性極性基を有する単量体
酸性極性基を有する単量体としては、（ａ）カルボキシル基（−ＣＯＯＨ）を有するα，β−エチレン性不飽和化合物及び（ｂ）スルホン基（−ＳＯ₃Ｈ）を有するα，β−エチレン性不飽和化合物を挙げることができる。
【０１７０】
（ａ）の−ＣＯＯ基を有するα，β−エチレン性不飽和化合物の例としては、アクリル酸、メタアクリル酸、フマール酸、マレイン酸、イタコン酸、ケイ皮酸、マレイン酸モノブチルエステル、マレイン酸モノオクチルエステル、およびこれらのＮａ、Ｚｎ等の金属塩類等を挙げることができる。
【０１７１】
（ｂ）の−ＳＯ₃Ｈ基を有するα，β−エチレン性不飽和化合物の例としてはスルホン化スチレン、そのＮａ塩、アリルスルホコハク酸、アリルスルホコハク酸オクチル、そのＮａ塩等を挙げることができる。
【０１７２】
（４）塩基性極性基を有するモノマー
塩基性極性基を有するモノマーとしては、（ｉ）アミン基或いは４級アンモニウム基を有する炭素原子数１〜１２、好ましくは２〜８、特に好ましくは２の脂肪族アルコールの（メタ）アクリル酸エステル、（ii）（メタ）アクリル酸アミド或いは随意Ｎ上で炭素原子数１〜１８のアルキル基でモノ又はジ置換された（メタ）アクリル酸アミド、（iii）Ｎを環員として有する複素環基で置換されたビニール化合物及び（iv）Ｎ，Ｎ−ジアリル−アルキルアミン或いはその四級アンモニウム塩を例示することができる。中でも、（ｉ）のアミン基或いは四級アンモニウム基を有する脂肪族アルコールの（メタ）アクリル酸エステルが塩基性極性基を有するモノマーとして好ましい。
【０１７３】
（ｉ）のアミン基或いは四級アンモニウム基を有する脂肪族アルコールの（メタ）アクリル酸エステルの例としては、ジメチルアミノエチルアクリレート、ジメチルアミノエチルメタクリレート、ジエチルアミノエチルアクリレート、ジエチルアミノエチルメタクリレート、上記４化合物の四級アンモニウム塩、３−ジメチルアミノフェニルアクリレート、２−ヒドロキシ−３−メタクリルオキシプロピルトリメチルアンモニウム塩等を挙げることができる。
【０１７４】
（ii）の（メタ）アクリル酸アミド或いはＮ上で随意モノ又はジアルキル置換された（メタ）アクリル酸アミドとしては、アクリルアミド、Ｎ−ブチルアクリルアミド、Ｎ，Ｎ−ジブチルアクリルアミド、ピペリジルアクリルアミド、メタクリルアミド、Ｎ−ブチルメタクリルアミド、Ｎ，Ｎ−ジメチルアクリルアミド、Ｎ−オクタデシルアクリルアミド等を挙げることができる。
【０１７５】
（iii）のＮを環員として有する複素環基で置換されたビニル化合物としては、ビニルピリジン、ビニルピロリドン、ビニル−Ｎ−メチルピリジニウムクロリド、ビニル−Ｎ−エチルピリジニウムクロリド等を挙げることができる。
【０１７６】
（iv）のＮ，Ｎ−ジアリル−アルキルアミンの例としては、Ｎ，Ｎ−ジアリルメチルアンモニウムクロリド、Ｎ，Ｎ−ジアリルエチルアンモニウムクロリド等を挙げることができる。
【０１７７】
（重合開始剤）
本発明に用いられるラジカル重合開始剤は、水溶性であれば適宜使用が可能である。例えば、過硫酸塩（例えば、過硫酸カリウム、過硫酸アンモニウム等）、アゾ系化合物（例えば、４，４′−アゾビス４−シアノ吉草酸及びその塩、２，２′−アゾビス（２−アミジノプロパン）塩等）、パーオキシド化合物等が挙げられる。更に、上記ラジカル性重合開始剤は、必要に応じて還元剤と組み合わせレドックス系開始剤とする事が可能である。レドックス系開始剤を用いることにより、重合活性が上昇し、重合温度の低下が図れ、更に重合時間の短縮が達成でき好ましい。
【０１７８】
重合温度は、重合開始剤の最低ラジカル生成温度以上であればどの温度を選択しても良いが例えば５０℃から９０℃の範囲が用いられる。但し、常温開始の重合開始剤、例えば過酸化水素−還元剤（アスコルビン酸等）の組み合わせを用いる事で、室温またはそれ以上の温度で重合する事も可能である。
【０１７９】
（連鎖移動剤）
分子量を調整することを目的として、公知の連鎖移動剤を用いることができる。連鎖移動剤としては、特に限定されるものではないが、例えば、オクチルメルカプタン、ドデシルメルカプタン、ｔｅｒｔ−ドデシルメルカプタン等のメルカプト基を有する化合物が用いられる。特に、メルカプト基を有する化合物は、加熱定着時の臭気を抑制し、分子量分布がシャープであるトナーが得られ、保存性、定着強度、耐オフセット性に優れるため好ましく用いられ、好ましいものとしては、例えば、チオグリコール酸エチル、チオグリコール酸プロピル、チオグリコール酸プロピル、チオグリコール酸ブチル、チオグリコール酸ｔ−ブチル、チオグリコール酸２−エチルヘキシル、チオグリコール酸オクチル、チオグリコール酸デシル、チオグリコール酸ドデシル、エチレングリコールのメルカプト基を有する化合物、ネオペンチルグリコールのメルカプト基を有する化合物、ペンタエリストールのメルカプト基を有する化合物を挙げることができる。このうち、トナー加熱定着時の臭気を抑制する観点で、ｎ−オクチル−３−メルカプトプロピオン酸エステルが、特に好ましい。
【０１８０】
（界面活性剤）
前述の重合性単量体を使用して、特にミニエマルジョン重合を行うためには、界面活性剤を使用して水系媒体中に油滴分散を行うことが好ましい。この際に使用することのできる界面活性剤としては、特に限定されるものでは無いが、下記のイオン性界面活性剤を好適な化合物の例として挙げることができる。
【０１８１】
イオン性界面活性剤としては、例えば、スルホン酸塩（ドデシルベンゼンスルホン酸ナトリウム、アリールアルキルポリエーテルスルホン酸ナトリウム、３，３−ジスルホンジフェニル尿素−４，４−ジアゾ−ビス−アミノ−８−ナフトール−６−スルホン酸ナトリウム、オルト−カルボキシベンゼン−アゾ−ジメチルアニリン、２，２，５，５−テトラメチル−トリフェニルメタン−４，４−ジアゾ−ビス−β−ナフトール−６−スルホン酸ナトリウム等）、硫酸エステル塩（ドデシル硫酸ナトリウム、テトラデシル硫酸ナトリウム、ペンタデシル硫酸ナトリウム、オクチル硫酸ナトリウム等）、脂肪酸塩（オレイン酸ナトリウム、ラウリン酸ナトリウム、カプリン酸ナトリウム、カプリル酸ナトリウム、カプロン酸ナトリウム、ステアリン酸カリウム、オレイン酸リチウム等）が挙げられる。
【０１８２】
また、ノニオン性界面活性剤も使用することができる。具体的には、例えば、ポリエチレンオキサイド、ポリプロピレンオキサイド、ポリプロピレンオキサイドとポリエチレンオキサイドの組み合わせ、ポリエチレングリコールと高級脂肪酸とのエステル、アルキルフェノールポリエチレンオキサイド、高級脂肪酸とポリエチレングリコールのエステル、高級脂肪酸とポリプロピレンオキサイドのエステル、ソルビタンエステル等をあげることができる。
【０１８３】
本発明において、これら界面活性剤は、主に乳化重合時の乳化剤として使用されるが、他の工程または他の目的で使用してもよい。
【０１８４】
本発明のトナーに用いられる樹脂粒子、更にそれを構成成分として有する本発明のトナーの分子量分布について説明する。
【０１８５】
本発明のトナーは、ピークまたは肩が１００，０００〜１，０００，０００、および１，０００〜５０，０００に存在することが好ましく、さらにピークまたは肩が１００，０００〜１，０００，０００、２５，０００〜１５０，０００及び１，０００〜５０，０００に存在することがさらに好ましい。
【０１８６】
樹脂粒子の分子量は、１００，０００〜１，０００，０００の領域にピークもしくは肩を有する高分子量成分と、１，０００から５０，０００未満の領域にピークもしくは肩を有する低分子量成分の両成分を少なくとも含有する樹脂が好ましい。さらに好ましくは、ピーク分子量で１５，０００〜１００，０００の部分にピーク又は肩を有する中間分子量体の樹脂を使用することが好ましい。
【０１８７】
トナーあるいは樹脂の分子量測定方法は、ＴＨＦ（テトラヒドロフラン）を溶媒としたＧＰＣ（ゲルパーミエーションクロマトグラフィー）による測定がよい。すなわち、測定試料０．５〜５ｍｇ、より具体的には１ｍｇに対してＴＨＦを１．０ｍｌ加え、室温にてマグネチックスターラーなどを用いて撹拌を行い、充分に溶解させる。ついで、ポアサイズ０．４５〜０．５０μｍのメンブランフィルターで処理した後に、ＧＰＣへ注入する。ＧＰＣの測定条件は、４０℃にてカラムを安定化させ、ＴＨＦを毎分１．０ｍｌの流速で流し、１ｍｇ／ｍｌの濃度の試料を約１００μｌ注入して測定する。カラムは、市販のポリスチレンジェルカラムを組み合わせて使用することが好ましい。例えば、昭和電工社製のＳｈｏｄｅｘ ＧＰＣ ＫＦ−８０１、８０２、８０３、８０４、８０５、８０６、８０７の組合せや、東ソー社製のＴＳＫｇｅｌＧ１０００Ｈ、Ｇ２０００Ｈ、Ｇ３０００Ｈ、Ｇ４０００Ｈ、Ｇ５０００Ｈ、Ｇ６０００Ｈ、Ｇ７０００Ｈ、ＴＳＫｇｕａｒｄ ｃｏｌｕｍｎの組合せなどを挙げることができる。又、検出器としては、屈折率検出器（ＩＲ検出器）、あるいはＵＶ検出器を用いるとよい。試料の分子量測定では、試料の有する分子量分布を単分散のポリスチレン標準粒子を用いて作成した検量線を用いて算出する。検量線作成用のポリスチレンとしては１０点程度用いるとよい。
【０１８８】
本発明のトナー粒子の作製時に用いられる凝集剤について説明する。
本発明で用いられる凝集剤は、金属塩の中から選択されるものが好ましい。
【０１８９】
金属塩としては、一価の金属、例えばナトリウム、カリウム、リチウム等のアルカリ金属の塩、二価の金属、例えばリチウム、マグネシウム等のアルカリ土類金属の塩、マンガン、銅等の二価の金属塩、鉄、アルミニウム等の三価の金属塩等が挙げられる。
【０１９０】
これら金属塩の具体的な例を以下に示す。一価の金属の金属塩の具体例として、塩化ナトリウム、塩化カリウム、塩化リチウム、二価の金属の金属塩として塩化リチウム、塩化亜鉛、硫酸銅、硫酸マグネシウム、硫酸マンガン等が挙げられる。三価の金属塩としては、塩化アルミニウム、塩化鉄等が挙げられる。これらは、目的に応じて適宜選択される。一般的には一価の金属塩より二価の金属塩のほうが臨界凝集濃度（凝析値或いは凝析点）が小さく、更に三価の金属塩の臨界凝集濃度は小さい。
【０１９１】
本発明で言う臨界凝集濃度とは、水性分散液中の分散物の安定性に関する指標であり、凝集剤を添加し、凝集が起こる点の濃度を示している。この臨界凝集濃度は、ラテックス自身及び分散剤により大きく変化する。例えば、岡村誠三他著高分子化学１７，６０１（１９６０）等に記述されており、これらの記載に従えば、その値を知ることが出来る。又、別の方法として、目的とする粒子分散液に所望の塩を濃度を変えて添加し、その分散液のζ電位を測定し、ζ電位が変化し出す点の塩濃度を臨界凝集濃度とすることも可能である。
【０１９２】
本発明では、金属塩を用いて臨界凝集濃度以上の濃度になるように重合体微粒子分散液を処理する。この時、当然の事ながら、金属塩を直接加えるか、水溶液として加えるかは、その目的に応じて任意に選択される。水溶液として加える場合には、重合体粒子分散液の容量と金属塩水溶液の総容量に対し、添加した金属塩が重合体粒子の臨界凝集濃度以上になる必要がある。
【０１９３】
本発明における凝集剤たる金属塩の濃度は、臨界凝集濃度以上であれば良いが、好ましくは臨界凝集濃度の１．２倍以上、更に好ましくは１．５倍以上添加される。
【０１９４】
本発明においては、トナー粒子への過剰帯電を抑え、均一な帯電性を付与するという観点から、特に環境に対して帯電性を安定化し、維持する為に、本発明の静電荷像現像用トナーは、上記に記載の金属元素（形態として、金属、金属イオン等が挙げられる）をトナー中に２５０〜２００００ｐｐｍ含有することが好ましく、更に好ましくは８００〜５０００ｐｐｍである。
【０１９５】
また、本発明においては、凝集剤に用いる２価（３価）の金属元素と後述する凝集停止剤として加える１価の金属元素の合計値が３５０〜３５０００ｐｐｍであることが好ましい。
【０１９６】
トナー中の金属イオン残存量の測定は、蛍光Ｘ線分析装置「システム３２７０型」〔理学電気工業（株）製〕を用いて、凝集剤として用いられる金属塩の金属種（例えば、塩化カルシウムに由来するカルシウム等）から発する蛍光Ｘ線強度を測定することによって求めることができる。具体的な測定法としては、凝集剤金属塩の含有割合が既知のトナーを複数用意し、各トナー５ｇをペレット化し、凝集剤金属塩の含有割合（質量ｐｐｍ）と、当該金属塩の金属種からの蛍光Ｘ線強度（ピーク強度）との関係（検量線）を測定する。次いで、凝集剤金属塩の含有割合を測定すべきトナー（試料）を同様にペレット化し、凝集剤金属塩の金属種からの蛍光Ｘ線強度を測定し、含有割合すなわち「トナー中の金属イオン残存量」を求めることが出来る。
【０１９７】
本発明に用いられる現像剤について説明する。
本発明のトナーは、一成分現像剤でも二成分現像剤として用いてもよい。
【０１９８】
一成分現像剤として用いる場合は、非磁性一成分現像剤、あるいはトナー中に０．１〜０．５μｍ程度の磁性粒子を含有させ磁性一成分現像剤としたものがあげられ、いずれも使用することができる。
【０１９９】
また、キャリアと混合して二成分現像剤として用いることができる。この場合は、キャリアの磁性粒子として、鉄、フェライト、マグネタイト等の金属、それらの金属とアルミニウム、鉛等の金属との合金等の従来から公知の材料を用いることが出来る。特にフェライト粒子が好ましい。上記磁性粒子は、その体積平均粒径としては１５〜１００μｍ、より好ましくは２５〜８０μｍのものがよい。
【０２００】
キャリアの体積平均粒径の測定は、代表的には湿式分散機を備えたレーザ回折式粒度分布測定装置「ヘロス（ＨＥＬＯＳ）」（シンパティック（ＳＹＭＰＡＴＥＣ）社製）により測定することができる。
【０２０１】
キャリアは、磁性粒子が更に樹脂により被覆されているもの、あるいは樹脂中に磁性粒子を分散させたいわゆる樹脂分散型キャリアが好ましい。コーティング用の樹脂組成としては、特に限定は無いが、例えば、オレフィン系樹脂、スチレン系樹脂、スチレン−アクリル系樹脂、シリコーン系樹脂、エステル系樹脂或いはフッ素含有重合体系樹脂等が用いられる。また、樹脂分散型キャリアを構成するための樹脂としては、特に限定されず公知のものを使用することができ、例えば、スチレン−アクリル系樹脂、ポリエステル樹脂、フッ素系樹脂、フェノール樹脂等を使用することができる。
【０２０２】
本発明に用いられる画像形成装置について説明する。
本発明のトナーは、トナー像が形成された画像形成支持体を、定着装置を構成する加熱ローラーと加圧ローラーとの間に通過させて定着する工程を含む画像形成装置に好適に使用される。
【０２０３】
図１は、本発明のトナーを用いる定着装置の一例を示す断面図であり、図１に示す定着装置は、加熱ローラー１０と、これに当接する加圧ローラー２０とを備えている。なお、図１において、Ｔは転写紙（画像形成支持体）上に形成されたトナー像である。
【０２０４】
加熱ローラー１０は、フッ素樹脂または弾性体からなる被覆層１２が芯金１１の表面に形成されてなり、線状ヒーターよりなる加熱部材１３を内包している。
【０２０５】
芯金１１は、金属から構成され、その内径は１０〜７０ｍｍとされる。芯金１１を構成する金属としては特に限定されるものではないが、例えば鉄、アルミニウム、銅等の金属あるいはこれらの合金を挙げることができる。
【０２０６】
芯金１１の肉厚は０．１〜１５ｍｍとされ、省エネルギーの要請（薄肉化）と、強度（構成材料に依存）とのバランスを考慮して決定される。例えば、０．５７ｍｍの鉄よりなる芯金と同等の強度を、アルミニウムよりなる芯金で保持するためには、その肉厚を０．８ｍｍとする必要がある。
【０２０７】
被覆層１２を構成するフッ素樹脂としては、ＰＴＦＥ（ポリテトラフルオロエチレン）およびＰＦＡ（テトラフルオロエチレン−パーフルオロアルキルビニルエーテル共重合体）などを例示することができる。
【０２０８】
フッ素樹脂からなる被覆層１２の厚みは１０〜５００μｍとされ、好ましくは２０〜４００μｍとされる。
【０２０９】
フッ素樹脂からなる被覆層１２の厚みが１０μｍ未満であると、被覆層としての機能を十分に発揮することができず、定着装置としての耐久性を確保することができない。一方、５００μｍを超える被覆層の表面には紙粉によるキズがつきやすく、当該キズ部にトナーなどが付着し、これに起因する画像汚れを発生する問題がある。また、被覆層１２を構成する弾性体としては、ＬＴＶ、ＲＴＶ、ＨＴＶなどの耐熱性の良好なシリコーンゴムおよびシリコーンスポンジゴムなどを用いることが好ましい。
【０２１０】
被覆層１２を構成する弾性体のアスカーＣ硬度は、８０°未満とされ、好ましくは６０°未満とされる。また、弾性体からなる被覆層１２の厚みは０．１〜３０ｍｍとされ、好ましくは０．１〜２０ｍｍとされる。
【０２１１】
被覆層１２を構成する弾性体のアスカーＣ硬度が８０°を超える場合、および当該被覆層１２の厚みが０．１ｍｍ未満である場合には、定着のニップを大きくすることができず、ソフト定着の効果（例えば、平滑化された界面のトナー層による色再現性の向上効果）を発揮することができない。
【０２１２】
加熱部材１３としては、ハロゲンヒーターを好適に使用することができる。
加圧ローラー２０は、弾性体からなる被覆層２２が芯金２１の表面に形成されてなる。被覆層２２を構成する弾性体としては特に限定されるものではなく、ウレタンゴム、シリコーンゴムなどの各種軟質ゴムおよびスポンジゴムを挙げることができ、被覆層１２を構成するものとして例示したシリコーンゴムおよびシリコーンスポンジゴムを用いることが好ましい。
【０２１３】
被覆層２２を構成する弾性体のアスカーＣ硬度は、８０°未満とされ、好ましくは７０°未満、更に好ましくは６０°未満とされる。
【０２１４】
また、被覆層２２の厚みは０．１〜３０ｍｍとされ、好ましくは０．１〜２０ｍｍとされる。
【０２１５】
被覆層２２を構成する弾性体のアスカーＣ硬度が８０°を超える場合、および被覆層２２の厚みが０．１ｍｍ未満である場合には、定着のニップを大きくすることができず、ソフト定着の効果を発揮することができない。
【０２１６】
芯金２１を構成する材料としては特に限定されるものではないが、アルミニウム、鉄、銅などの金属またはそれらの合金を挙げることができる。
【０２１７】
加熱ローラー１０と加圧ローラー２０との当接荷重（総荷重）としては、通常４０〜３５０Ｎとされ、好ましくは５０〜３００Ｎ、さらに好ましくは５０〜２５０Ｎとされる。この当接荷重は、加熱ローラー１０の強度（芯金１１の肉厚）を考慮して規定され、例えば０．３ｍｍの鉄よりなる芯金を有する加熱ローラーにあっては、２５０Ｎ以下とすることが好ましい。
【０２１８】
また、耐オフセット性および定着性の観点から、ニップ幅としては４〜１０ｍｍであることが好ましく、当該ニップの面圧は０．６×１０⁵Ｐａ〜１．５×１０⁵Ｐａであることが好ましい。
【０２１９】
図１に示した定着装置による定着条件の一例を示せば、定着温度（加熱ローラー１０の表面温度）が１５０〜２１０℃とされ、定着線速が８０〜６４０ｍｍ／ｓｅｃとされる。
【０２２０】
本発明において使用する定着装置には、必要に応じてクリーニング機構を付与してもよい。この場合には、シリコーンオイルを定着部の上ローラー（加熱ローラー）に供給する方式として、シリコーンオイルを含浸したパッド、ローラー、ウェッブ等で供給し、クリーニングする方法が使用できる。
【０２２１】
シリコーンオイルとしては耐熱性の高いものが使用され、ポリジメチルシリコーン、ポリフェニルメチルシリコーン、ポリジフェニルシリコーン等が使用される。粘度の低いものは使用時に流出量が大きくなることから、２０℃における粘度が１〜１００Ｐａ・ｓのものが好適に使用される。
【０２２２】
但し、本発明による効果は、シリコーンオイルを供給しない、または、シリコーンオイルの供給量がきわめて低い定着装置により、画像を形成する工程を含む場合に特に顕著に発揮される。従って、シリコーンオイルを供給する場合であっても、その供給量はＡ４用紙１枚当たり２ｍｇ以下とすることが好ましい。
【０２２３】
シリコーンオイルの供給量をＡ４用紙１枚当たり２ｍｇ以下とすることにより、定着後の転写紙（画像支持体）に対するシリコーンオイルの付着量が少なくなり、転写紙へ付着したシリコーンオイルによるボールペン等の油性ペンの記入しずらさがなく、加筆性が損なわれることはない。
【０２２４】
また、シリコーンオイルの変質による耐オフセット性の経時的な低下、シリコーンオイルによる光学系や帯電極の汚染などの問題を回避することができる。
【０２２５】
ここに、シリコーンオイルの供給量は、所定温度に加熱した定着装置（ローラー間）に転写紙（Ａ４サイズの白紙）を連続して１００枚通過させ、通紙前後における定着装置の質量変化（Δｗ）を測定して算出される（Δｗ／１００）。
【０２２６】
本発明に画像形成装置に用いられるクリーニングブレードについて説明する。本発明に用いられるクリーニングブレードは弾性体ゴムブレードが好ましく、その物性はゴム硬度と反発弾性を同時にコントロールすることにより、本発明のトルク変動を小さく制御でき、より有効にブレードの反転を抑制できる。２５±５℃に於けるブレードのＪＩＳ Ａ硬度が６５よりも小さくなるとブレードの反転が起こり易くなり、８０より大きくなるとクリーニング性能が低下する。また、反発弾性が８０を超えるとブレードの反転がおこり易くなり、２０以下だとクリーニング性能が低下する。より好ましい反発弾性は２０以上８０以下である。ヤング率は、２９４〜５８８Ｎ／ｃｍ²の範囲のものが好ましい。（ＪＩＳＡ硬度及び反発弾性ともＪＩＳ Ｋ ６３０１の加硫ゴム物理試験方法に基づき測定する。反発弾性の数値は％を示す。）
前記クリーニングブレードに用いられる弾性体ゴムブレードの材質としてはウレタンゴム、シリコンゴム、フッソゴム、クロロピレンゴム、ブタジエンゴム等が知られているが、これらの内、ウレタンゴムは他のゴムに比して摩耗特性が優れている点で特に好ましい。例えば、特開昭５９−３０５７４号に記載のポリカプロラクトンエステルとポリイソシアネートとを反応硬化せしめて得られるウレタンゴム等が好ましい。
【０２２７】
本発明において、この弾性ゴムブレードの支持部材への固定方法は、感光体当接面側で支持部材に実質的に保持されていることが好ましい。このような保持方法を採ることにより、クリーニングブレードのトルク変動を安定化させることができる。
【０２２８】
本発明の画像形成装置に用いられるクリーニングブレードの適正圧接条件について説明する。
【０２２９】
感光体表面への弾性ゴムブレードの適正圧接条件は、諸特性の微妙なバランスにより決められており、かなり狭いものである。弾性ゴムブレードの厚み等の特性によっても変わり、設定には精度を要する。しかし、弾性ゴムブレードは作製時にどうしてもその厚みに多少のバラツキができるため、適正な条件で常に設定されるとはいえず、例え当初は適正に設定されても、適正領域が狭いため使用の過程で適正領域からはずれてしまうこともある。特に高分子量のバインダー樹脂を用いた有機感光層と組み合わせた場合、適正領域からはずれると、フィルミング、黒ポチ等の画像欠陥が生じやすくなる。
【０２３０】
従って、弾性ゴムブレードの特性のバラツキ等をキャンセルするための方策もとる必要があり、弾性ゴムブレードの厚みのバラツキが例えあっても、感光体面への圧接力等に影響がでない、上記設定方法が有効なのであろう。
【０２３１】
本発明において、弾性ゴムブレードの自由端は、感光体の回転方向と反対方向（カウンター方向）にして圧接することが好ましい。
【０２３２】
クリーニングブレードは、必要に応じ、クリーニングブレードのエッジ部にフッ素系潤滑剤をスプレー塗布するか、もしくは、その上にさらに、幅方向全域にわたった先端部に、下記フッ素系ポリマーおよびフッ素系樹脂粉体をフッ素系溶剤に分散させた分散体を塗布することが好ましい。
【０２３３】
次に、本発明に画像形成装置に用いられる有機感光体について記載する。
本発明において、有機電子写真感光体（有機感光体）とは電子写真感光体の構成に必要不可欠な電荷発生機能及び電荷輸送機能の少なくとも一方の機能を有機化合物に持たせて構成された電子写真感光体を意味し、公知の有機電荷発生物質又は有機電荷輸送物質から構成された感光体、電荷発生機能と電荷輸送機能を高分子錯体で構成した感光体等公知の有機電子写真感光体を全て含有する。
【０２３４】
以下に本発明に用いられる有機感光体の構成について記載する。
導電性支持体
本発明の感光体に用いられる導電性支持体としてはシート状、円筒状のどちらを用いても良いが、画像形成装置をコンパクトに設計するためには円筒状導電性支持体の方が好ましい。
【０２３５】
本発明の円筒状導電性支持体とは回転することによりエンドレスに画像を形成できるに必要な円筒状の支持体を意味し、真直度で０．１ｍｍ以下、振れ０．１ｍｍ以下の範囲にある導電性の支持体が好ましい。この真円度及び振れの範囲を超えると、良好な画像形成が困難になる。
【０２３６】
導電性の材料としてはアルミニウム、ニッケルなどの金属ドラム、又はアルミニウム、酸化錫、酸化インジュウムなどを蒸着したプラスチックドラム、又は導電性物質を塗布した紙・プラスチックドラムを使用することができる。導電性支持体としては常温で比抵抗１０³Ωｃｍ以下が好ましい。
【０２３７】
本発明で用いられる導電性支持体は、その表面に封孔処理されたアルマイト膜が形成されたものを用いても良い。アルマイト処理は、通常例えばクロム酸、硫酸、シュウ酸、リン酸、硼酸、スルファミン酸等の酸性浴中で行われるが、硫酸中での陽極酸化処理が最も好ましい結果を与える。硫酸中での陽極酸化処理の場合、硫酸濃度は１００〜２００ｇ／ｌ、アルミニウムイオン濃度は１〜１０ｇ／ｌ、液温は２０℃前後、印加電圧は約２０Ｖで行うのが好ましいが、これに限定されるものではない。又、陽極酸化被膜の平均膜厚は、通常２０μｍ以下、特に１０μｍ以下が好ましい。
【０２３８】
中間層
本発明においては導電性支持体と感光層の間に、バリヤー機能を備えた中間層を設けることもできる。
【０２３９】
本発明においては導電性支持体と前記感光層のとの接着性改良、或いは該支持体からの電荷注入を防止するために、該支持体と前記感光層の間に中間層（下引層も含む）を設けることもできる。該中間層の材料としては、ポリアミド樹脂、塩化ビニル樹脂、酢酸ビニル樹脂並びに、これらの樹脂の繰り返し単位のうちの２つ以上を含む共重合体樹脂が挙げられる。これら下引き樹脂の中で繰り返し使用に伴う残留電位増加を小さくできる樹脂としてはポリアミド樹脂が好ましい。又、これら樹脂を用いた中間層の膜厚は０．０１〜０．５μｍが好ましい。
【０２４０】
又本発明に最も好ましく用いられる中間層はシランカップリング剤、チタンカップリング剤等の有機金属化合物を熱硬化させた硬化性金属樹脂を用いた中間層が挙げられる。硬化性金属樹脂を用いた中間層の膜厚は、０．１〜２μｍが好ましい。
【０２４１】
感光層
本発明の感光体の感光層構成は前記中間層上に電荷発生機能と電荷輸送機能を１つの層に持たせた単層構造の感光層構成でも良いが、より好ましくは感光層の機能を電荷発生層（ＣＧＬ）と電荷輸送層（ＣＴＬ）に分離した構成をとるのがよい。機能を分離した構成を取ることにより繰り返し使用に伴う残留電位増加を小さく制御でき、その他の電子写真特性を目的に合わせて制御しやすい。負帯電用の感光体では中間層の上に電荷発生層（ＣＧＬ）、その上に電荷輸送層（ＣＴＬ）の構成を取ることが好ましい。正帯電用の感光体では前記層構成の順が負帯電用感光体の場合の逆となる。本発明の最も好ましい感光層構成は前記機能分離構造を有する負帯電感光体構成である。
【０２４２】
以下に機能分離負帯電感光体の感光層構成について説明する。
電荷発生層
電荷発生層：電荷発生層には電荷発生物質（ＣＧＭ）を含有する。その他の物質としては必要によりバインダー樹脂、その他添加剤を含有しても良い。
【０２４３】
電荷発生物質（ＣＧＭ）としては公知の電荷発生物質（ＣＧＭ）を用いることができる。例えばフタロシアニン顔料、アゾ顔料、ペリレン顔料、アズレニウム顔料などを用いることができる。これらの中で繰り返し使用に伴う残留電位増加を最も小さくできるＣＧＭは複数の分子間で安定な凝集構造をとりうる立体、電位構造を有するものであり、具体的には特定の結晶構造を有するフタロシアニン顔料、ペリレン顔料のＣＧＭが挙げられる。例えばＣｕ−Ｋα線に対するブラッグ角２θが２７．２°に最大ピークを有するチタニルフタロシアニン、同２θが１２．４に最大ピークを有するベンズイミダゾールペリレン等のＣＧＭは繰り返し使用に伴う劣化がほとんどなく、残留電位増加小さくすることができる。
【０２４４】
電荷発生層にＣＧＭの分散媒としてバインダーを用いる場合、バインダーとしては公知の樹脂を用いることができるが、最も好ましい樹脂としてはホルマール樹脂、ブチラール樹脂、シリコーン樹脂、シリコーン変性ブチラール樹脂、フェノキシ樹脂等が挙げられる。バインダー樹脂と電荷発生物質との割合は、バインダー樹脂１００質量部に対し２０〜６００質量部が好ましい。これらの樹脂を用いることにより、繰り返し使用に伴う残留電位増加を最も小さくできる。電荷発生層の膜厚は０．０１μｍ〜２μｍが好ましい。
【０２４５】
電荷輸送層
電荷輸送層：電荷輸送層には電荷輸送物質（ＣＴＭ）及びＣＴＭを分散し製膜するバインダー樹脂を含有する。その他の物質としては必要により酸化防止剤等の添加剤を含有しても良い。
【０２４６】
電荷輸送物質（ＣＴＭ）としては公知の電荷輸送物質（ＣＴＭ）を用いることができる。例えばトリフェニルアミン誘導体、ヒドラゾン化合物、スチリル化合物、ベンジジン化合物、ブタジエン化合物などを用いることができる。これら電荷輸送物質は通常、適当なバインダー樹脂中に溶解して層形成が行われる。これらの中で繰り返し使用に伴う残留電位増加を最も小さくできるＣＴＭは高移動度で、且つ組み合わされるＣＧＭとのイオン化ポテンシャル差が０．５（ｅＶ）以下の特性を有するものであり、好ましくは０．２５（ｅＶ）以下である。
【０２４７】
ＣＧＭ、ＣＴＭのイオン化ポテンシャルは表面分析装置ＡＣ−１（理研計器社製）で測定される。
【０２４８】
電荷輸送層（ＣＴＬ）に用いられる樹脂としては、例えばポリスチレン、アクリル樹脂、メタクリル樹脂、塩化ビニル樹脂、酢酸ビニル樹脂、ポリビニルブチラール樹脂、エポキシ樹脂、ポリウレタン樹脂、フェノール樹脂、ポリエステル樹脂、アルキッド樹脂、ポリカーボネート樹脂、シリコーン樹脂、メラミン樹脂並びに、これらの樹脂の繰り返し単位のうちの２つ以上を含む共重合体樹脂。又これらの絶縁性樹脂の他、ポリ−Ｎ−ビニルカルバゾール等の高分子有機半導体が挙げられる。
【０２４９】
これらＣＴＬのバインダーとして最も好ましいものはポリカーボネート樹脂である。本発明に係わるポリカーボネートとしては、粘度平均分子量４０，０００以上のものが好ましく、更に好ましくは５０，０００以上である。また、本発明に係わるポリカーボネートの具体例としては、特開平８−２７２１２５号、９頁〜１４頁に記載の化合物Ｐ₁−１〜Ｐ₁−１２、Ｐ₂−１〜Ｐ₂−１０及びＰ₃−１〜Ｐ₃−１０等が挙げられる。ポリカーボネート樹脂はＣＴＭの分散性、電子写真特性を良好にすることにおいて、最も好ましい。バインダー樹脂と電荷輸送物質との割合は、バインダー樹脂１００質量部に対し１０〜２００質量部が好ましい。又、電荷輸送層の膜厚は１０〜４０μｍが好ましい。
【０２５０】
保護層
感光体の保護層として、各種樹脂層を設けることができる。特に架橋系の樹脂層を設けることにより、本発明の機械的強度の強い有機感光体を得ることができる。
【０２５１】
本発明の中間層、感光層、保護層等の層形成に用いられる溶媒又は分散媒としては、ｎ−ブチルアミン、ジエチルアミン、エチレンジアミン、イソプロパノールアミン、トリエタノールアミン、トリエチレンジアミン、Ｎ，Ｎ−ジメチルホルムアミド、アセトン、メチルエチルケトン、メチルイソプロピルケトン、シクロヘキサノン、ベンゼン、トルエン、キシレン、クロロホルム、ジクロロメタン、１，２−ジクロロエタン、１，２−ジクロロプロパン、１，１，２−トリクロロエタン、１，１，１−トリクロロエタン、トリクロロエチレン、テトラクロロエタン、テトラヒドロフラン、ジオキソラン、ジオキサン、メタノール、エタノール、ブタノール、イソプロパノール、酢酸エチル、酢酸ブチル、ジメチルスルホキシド、メチルセロソルブ等が挙げられる。本発明はこれらに限定されるものではないが、ジクロロメタン、１，２−ジクロロエタン、メチルエチルケトン等が好ましく用いられる。また、これらの溶媒は単独或いは２種以上の混合溶媒として用いることもできる。
【０２５２】
次に本発明の有機電子写真感光体を製造するための塗布加工方法としては、浸漬塗布、スプレー塗布、円形量規制型塗布等の塗布加工法が用いられるが、感光層の上層側の塗布加工は下層の膜を極力溶解させないため、又、均一塗布加工を達成するためスプレー塗布又は円形量規制型（円形スライドホッパ型がその代表例）塗布等の塗布加工方法を用いるのが好ましい。なお本発明の保護層は前記円形量規制型塗布加工方法を用いるのが最も好ましい。前記円形量規制型塗布については例えば特開昭５８−１８９０６１号公報に詳細に記載されている。
【０２５３】
【実施例】
以下、本発明を実施例により説明するが、本発明はこれらに限定されない。
【０２５４】
実施例１
《脂肪酸リチウムの製造》
（脂肪酸リチウム１の製造）
反応装置として、図２に示す構造を有し、反応容器１００の容積が２０Ｌで、上方の攪拌羽根６００の長さが２７５ｍｍで、下方の攪拌羽根７００の長さが３１０ｍｍのものを用意した。
【０２５５】
反応装置の反応容器内に、Ａ．Ｖ（２０４）の７０％ステアリン酸含有フレーク状物（融点６３℃）２７５０ｇ、平均粒径が１７μｍの炭酸リチウム粉末（日本化学工業株式会社製で、商品名が炭酸リチウムＳ）３７７．６ｇおよび水１３００ｍｌ（前記フレーク状物量の４７％）からなる原料を一括投入し、前記容器を密閉した。なお、この時点での原料の温度は３０℃であった。回転軸４００を回転させてこの回転軸に軸着された２枚の攪拌羽根６００，７００によって前記原料を１６ｍ／ｓｅｃの速度（長い方の攪拌羽根の回転速度）で攪拌混合しながらジャケットへ６０℃の温水を通し、混合物を加熱した。前記反応容器１００内の温度が約４０℃に達すると、炭酸ガスが発生し始めて反応が開始され、前記容器内の圧力が上昇し、前記反応容器１００に設置した圧力計が０．０１９６ＭＰａ（０．２ｋｇ／ｃｍ²）を示した。また、反応によって水が生成した。引き続き、炭酸ガスを反応容器１００外に逃がさないように前記加熱および攪拌を続行すると、前記反応容器１００内の温度が上昇すると共に圧力が上昇した。このような高圧雰囲気において、反応容器１００内の水は霧状に存在した。反応中の最高圧力は、０．０４９ＭＰａ（０．５ｋｇ／ｃｍ²）（この時の前記反応容器１００内の温度は６０℃）であった。
【０２５６】
前記反応容器１００内の温度が７５℃に達した際に炭酸ガスの発生がなくなり、圧力が低下すると同時に内容物が固化し、反応が終結した。原料投入から反応終結までに３０分間を要した。また、反応生成物の水分含有量を測定したところ、１５．０％であった。
【０２５７】
その後、前記反応容器１００の空洞部２００の温水を抜いてスチームに切り替え、前記容器１００内の温度を１００℃以上に設定した。前述した２枚の攪拌羽根による攪拌を続行しながら減圧乾燥を３０分間行うことにより２００メッシュパスが９９％以上（粒径が７４μｍ以下）の脂肪酸リチウム１の微粉末を製造した。
【０２５８】
得られた脂肪酸リチウム１について、ＪＩＳ規格に定められた方法で遊離脂肪酸量を測定したところ、０．４３％、融点は２１７℃であった。また、粉末Ｘ線回折を行い、その結果を図３に示す。
【０２５９】
（脂肪酸リチウム２〜５の製造）
上記の脂肪酸リチウム１の製造において、反応時間と減圧乾燥時間を変えて、表１に記載のように脂肪酸成分、水分量（質量％）、遊離脂肪酸量（質量％）を調製した以外は同様にして、脂肪酸リチウム２〜５を各々、製造した。
【０２６０】
（脂肪酸リチウム６の製造）
脂肪酸リチウムの１の製造において、表１に記載のように、ステアリン酸の代わりにステアリン酸とパルミチン酸を質量比３９９：１７１とした以外は同様にして脂肪酸リチウム６を得た。
【０２６１】
得られた脂肪酸リチウム塩の各々の特性を表１に示す。
【０２６２】
【表１】

【０２６３】
《本発明に用いる無機・有機複合微粒子の製造》
平均粒子径１．０μｍのスチレン／アクリル有機微粒子（電気抵抗６．６×１０¹³Ω・ｃｍ）１００ｇに対して、一次粒子径が３０ｎｍの表面を酸化スズ処理した酸化チタン粒子商品名ＥＴ−３００Ｗ（石原産業社製）を４０ｇ添加しタービュラミキサにて混合した。ついで、粉砕機を改造したハイブリダイザ（奈良機械製作所社製）にて周速１００ｍ／ｓｅｃの条件で３分間処理して有機微粒子表面に酸化チタンが固着された無機／有機複合微粒子を作製した。これを「無機／有機複合微粒子１」とする。無機／有機複合微粒子１の電気抵抗は４．８×１０⁸Ω・ｃｍであった。
【０２６４】
《トナー用樹脂粒子の製造例》
（ラテックス：１ＨＭＬの調製）
（１）核粒子の調製（第１段重合）：
攪拌装置、温度センサー、冷却管、窒素導入装置を取り付けた５０００ｍｌのセパラブルフラスコに、アニオン系界面活性剤（ドデシルスルフォン酸ナトリウム：ＳＤＳ）７．０８ｇをイオン交換水３０１０ｇに溶解させた界面活性剤溶液（水系媒体）を仕込み、窒素気流下２３０ｒｐｍの攪拌速度で攪拌しながら、内温を８０℃に昇温させた。
【０２６５】
この界面活性剤溶液に、重合開始剤（過硫酸カリウム：ＫＰＳ）９．２ｇをイオン交換水２００ｇに溶解させた開始剤溶液を添加し、温度を７５℃とした後、スチレン７０．１ｇ、ｎ−ブチルアクリレート１９．９ｇ、メタクリル酸１０．９ｇからなる単量体混合液を１時間かけて滴下し、この系を７５℃にて２時間にわたり加熱、攪拌することにより重合（第１段重合）を行い、ラテックス（高分子量樹脂からなる樹脂粒子の分散液）を調製した。これを「ラテックス（１Ｈ）」とする。
【０２６６】
（２）中間層の形成（第２段重合）：
攪拌装置を取り付けたフラスコ内において、スチレン１０５．６ｇ、ｎ−ブチルアクリレート３０．０ｇ、メタクリル酸６．４ｇ、ｎ−オクチル−３−メルカプトプロピオン酸エステル５．６ｇからなる単量体混合液に、上記１９）で表される化合物（以下、「例示化合物（１９）」という。）７２．０ｇを添加し、８０℃に加温し溶解させて単量体溶液を調製した。
【０２６７】
一方、アニオン系界面活性剤（ＳＤＳ）１．６ｇをイオン交換水２７００ｍｌに溶解させた界面活性剤溶液を８０℃に加熱し、この界面活性剤溶液に、核粒子の分散液である前記ラテックス（１Ｈ）を固形分換算で２８ｇ添加した後、循環経路を有する機械式分散機「クレアミックス（ＣＬＥＡＲＭＩＸ）」（エム・テクニック（株）製）により、前記例示化合物（１９）の単量体溶液を混合分散させ、均一な分散粒子径（２８４ｎｍ）を有する乳化粒子（油滴）を含む分散液（乳化液）を調製した。
【０２６８】
次いで、この分散液（乳化液）に、重合開始剤（ＫＰＳ）５．１ｇをイオン交換水２４０ｍｌに溶解させた開始剤溶液と、イオン交換水７５０ｍｌとを添加し、この系を８０℃にて３時間にわたり加熱攪拌することにより重合（第２段重合）を行い、ラテックス（高分子量樹脂からなる樹脂粒子の表面が中間分子量樹脂により被覆された構造の複合樹脂粒子の分散液）を得た。これを「ラテックス（１ＨＭ）」とする。
【０２６９】
（３）外層の形成（第３段重合）：
上記のようにして得られたラテックス（１ＨＭ）に、重合開始剤（ＫＰＳ）７．４ｇをイオン交換水２００ｍｌに溶解させた開始剤溶液を添加し、８０℃の温度条件下に、スチレン３００ｇ、ｎ−ブチルアクリレート９５ｇ、メタクリル酸１５．３ｇ、ｎ−オクチル−３−メルカプトプロピオン酸エステル１０．４ｇからなる単量体混合液を１時間かけて滴下した。滴下終了後、２時間にわたり加熱攪拌することにより重合（第３段重合）を行った後、２８℃まで冷却しラテックス（高分子量樹脂からなる中心部と、中間分子量樹脂からなる中間層と、低分子量樹脂からなる外層とを有し、前記中間層に例示化合物（１９）が含有されている複合樹脂粒子の分散液）を得た。このラテックスを「ラテックス（１ＨＭＬ）」とする。
【０２７０】
このラテックス（１ＨＭＬ）を構成する複合樹脂粒子は、１３８，０００、８０，０００および１３，０００にピーク分子量を有するものであり、また、この複合樹脂粒子の個数平均粒径は１０２ｎｍであった。
【０２７１】
（ラテックス２ＨＬの調製）
（１）核粒子の調製（第１段重合）：
攪拌装置を取り付けたフラスコ内において、スチレン１０５．６ｇ、ｎ−ブチルアクリレート３０．０ｇ、メタクリル酸６．４ｇからなる単量体混合液に、例示化合物（１６）７２．０ｇを添加し、８０℃に加温し溶解させて単量体溶液を調製した。
【０２７２】
一方、アニオン系界面活性剤（ＳＤＳ）１．６ｇをイオン交換水２７００ｍｌに溶解させた界面活性剤溶液を８０℃に加熱し、この界面活性剤溶液に、循環経路を有する機械式分散機「クレアミックス（ＣＬＥＡＲＭＩＸ）」（エム・テクニック（株）製）により、前記例示化合物（１６）の単量体溶液を混合分散させ、均一な分散粒子径（２６８ｎｍ）を有する乳化粒子（油滴）を含む分散液（乳化液）を調製した。
【０２７３】
次いで、この分散液（乳化液）に、重合開始剤（ＫＰＳ）５．１ｇをイオン交換水２４０ｍｌに溶解させた開始剤溶液と、イオン交換水７５０ｍｌとを添加し、この系を８０℃にて３時間にわたり加熱攪拌することにより重合（第１段重合）を行い、ラテックス（高分子量樹脂からなる樹脂粒子の分散液）を調製した。これを「ラテックス（２Ｈ）」とする。
【０２７４】
（２）外層の形成（第２段重合）：
上記のようにして得られたラテックス（２Ｈ）に、重合開始剤（ＫＰＳ）１４．８ｇをイオン交換水４００ｍｌに溶解させた開始剤溶液を添加し、８０℃の温度条件下に、スチレン６００ｇ、ｎ−ブチルアクリレート１９０ｇ、メタクリル酸３０．０ｇ、ｎ−オクチル−３−メルカプトプロピオン酸エステル２０．８ｇからなる単量体混合液を１時間かけて滴下した。滴下終了後、２時間にわたり加熱攪拌することにより重合（第２段重合）を行った後、２８℃まで冷却しラテックス（高分子量樹脂からなる中心部と、低分子量樹脂からなる外層とを有し、前記中心部に例示化合物（１６）が含有されている複合樹脂粒子の分散液）を得た。このラテックスを「ラテックス（２ＨＬ）」とする。
【０２７５】
このラテックス（２ＨＬ）を構成する複合樹脂粒子は、１６８，０００および１１，０００にピーク分子量を有するものであり、また、この複合樹脂粒子の重量平均粒径は１２６ｎｍであった。
【０２７６】
《着色粒子の製造例》
（着色粒子１の製造）
ｎ−ドデシル硫酸ナトリウム５９．０ｇをイオン交換水１６００ｍｌに攪拌溶解した。この溶液を攪拌しながら、カーボンブラック「リーガル３３０」（キャボット社製）４２０．０ｇを徐々に添加し、次いで、「クレアミックス」（エム・テクニック（株）製）を用いて分散処理することにより、着色剤粒子の分散液（以下、「着色剤分散液」という。）を調製した。この着色剤分散液における着色剤粒子の粒子径を、電気泳動光散乱光度計「ＥＬＳ−８００」（大塚電子社製）を用いて測定したところ、重量平均粒子径で９８ｎｍであった。
【０２７７】
ラテックス（１ＨＭＬ）４２０．７ｇ（固形分換算）と、イオン交換水９００ｇと、着色剤分散液１６６ｇとを、温度センサー、冷却管、窒素導入装置、攪拌装置、粒径および形状のモニタリング装置を取り付けた反応容器（図４に示した構成の反応装置、交差角αは２５°）（図４に示した構成の反応装置、交差角αは２５°）に入れ攪拌した。内温を３０℃に調整した後、この溶液に５モル／リットルの水酸化ナトリウム水溶液を加えてｐＨを１１．０に調整した。
【０２７８】
次いで、塩化マグネシウム６水和物１２．１ｇをイオン交換水１０００ｍｌに溶解した水溶液を、攪拌下、３０℃にて１０分間かけて添加した。３分間放置した後に昇温を開始し、この系を６〜１０分間かけて９０±３℃まで昇温した（昇温速度＝１０℃／分）。その状態で、「コールターカウンターＴＡ−II」にて会合粒子の粒径を測定し、体積平均粒径が５．５μｍになった時点で、塩化ナトリウム８０．４ｇをイオン交換水１０００ｍｌに溶解した水溶液を添加して粒子成長を停止させ、さらに、熟成処理として液温度８５±２℃にて０．５〜１５時間にわたり加熱攪拌することにより融着を継続させた。
【０２７９】
その後、８℃／分の条件で３０℃まで冷却し、塩酸を添加してｐＨを２．０に調整し、攪拌を停止した。生成した会合粒子をヌッチェを用いて濾過し、イオン交換水で繰り返し洗浄し、その後、フラッシュジェットドライヤーを用いて吸気温度６０℃にて乾燥させ、ついで流動層乾燥機を用いて６０℃の温度で乾燥させ、離型剤〔例示化合物（１９）〕を含有し、表２に記載の物理的特性を有する着色粒子１を得た。
【０２８０】
（着色粒子２〜４の製造）
上記記載の着色粒子１の製造において、塩析／融着段階および形状制御工程のモニタリングにおいて、攪拌回転数、および加熱時間を制御することにより、形状および形状係数の変動係数を制御し、粒径および粒度分布の変動係数を任意に調整する以外は、同様にして、表２に示す形状特性および粒度分布特性からなる着色粒子２〜４を得た。
【０２８１】
（着色粒子５〜８の製造）
ラテックス（１ＨＭＬ）に代えて、ラテックス（２ＨＬ）４２０．７ｇ（固形分換算）を使用し、熟成処理時間を変更したこと以外は着色粒子製造例１〜４と同様にして、表２に示す形状特性および粒度分布特性からなる着色粒子５〜８を各々、得た。得られた着色粒子の物理的特性を表２に示す。
【０２８２】
【表２】

【０２８３】
《トナー粒子の製造》
以上のようにして得られた着色粒子１〜８の各々に、疎水性シリカ（数平均一次粒子径＝１０ｎｍ、疎水化度＝６３）を１．０質量％となる割合で添加するとともに、疎水性酸化チタン（数平均一次粒子径＝２５ｎｍ、疎水化度＝６０）を０．８質量％となる割合でそれぞれ添加し、ヘンシェルミキサーにより混合した。さらに、表３にしめす脂肪酸リチウム塩０．１質量％、無機／有機複合微粒子あるいは、チタン酸ストロンチウムをそれぞれ１質量％添加し、ヘンシェルミキサーにより混合し、表３に記載の静電荷像現像用トナー試料１〜１５を各々、製造した。
【０２８４】
尚、トナー試料１の作製に当たり、脂肪酸リチウム塩を添加しないトナーを比較用トナー１として作製した。トナー試料１の作製において、脂肪酸リチウム塩を用いず、ステアリン酸亜鉛（日本油脂社製ジンクステアレートＤ）を添加したものを比較用トナー２とする。
【０２８５】
【表３】

【０２８６】
ここで、本発明に係る静電荷像現像用トナー粒子と着色粒子との物理的特性の関係について説明する。
【０２８７】
本発明に係る着色粒子の製造においては、樹脂粒子と着色剤とを塩析／融着段階および形状制御工程時にモニタリングを行い、攪拌回転数、および加熱時間等の反応制御により、形状および形状係数の変動係数を制御し、粒径および粒度分布の変動係数の調製を行う。このようにして得られた着色粒子に外部添加剤を添加してトナー粒子を製造するが、外添剤は単にトナー粒子の表面に固着するのみで着色粒子に物理的変化がないので、得られたトナー粒子の物理的特性（形状および粒径等）は着色粒子の物理的特性と同一である。
【０２８８】
《キャリアの製造》
（フェライト芯材の製造）
ＭｎＯを２２ｍｏｌ％、Ｆｅ₂Ｏ₃を７８ｍｏｌ％を、湿式ボールミルで２時間粉砕、混合し乾燥させた後に、９００℃で２時間保持することにより仮焼成し、これをボールミルで３時間粉砕しスラリー化した。分散剤及びバインダーを添加し、スプレードライヤーにより造粒、乾燥し、その後１２００℃、３時間本焼成を行い、平均グレイン径５．２μｍ、抵抗４．３×１０⁸Ωのフェライト芯材粒子を得た。
【０２８９】
（樹脂被覆キャリアの製造）
まず、界面活性剤として炭素数１２のアルキル基を有するベンゼンスルホン酸ナトリウムを用いた水溶液媒体中の濃度を０．３質量％とした乳化重合法により、シクロヘキシルメタクリレート／メチルメタクリレート（共重合比５／５）の共重合体を合成し、体積平均一次粒径０．１μｍ、重量平均分子量（Ｍｗ）２００，０００、数平均分子量（Ｍｎ）９１，０００、Ｍｗ／Ｍｎ＝２．２、軟化点温度（Ｔｓｐ）２３０℃及びガラス転移温度（Ｔｇ）１１０℃樹脂微粒子を得た。なお、前記樹脂微粒子は、乳化状態において、水と共沸し、残存モノマー量を５１０ＰＰＭとした。
【０２９０】
次に、フェライト芯材粒子１００質量部と、前記樹脂微粒子２質量部とを、撹拌羽根付き高速撹拌混合機に投入し、１２０℃で３０分間撹拌混合して、機械的衝撃力の作用を使用して体積平均粒径６１μｍの樹脂被覆キャリアを得た。
【０２９１】
《現像剤の製造》
表３に記載のトナー試料１〜１５、比較用トナー試料１及び２と、上記記載のキャリアとを混合し、トナー濃度が６質量％の現像剤を調製した。得られた現像剤を各々、現像剤試料１〜１５、比較用現像剤１、２とする。
【０２９２】
《感光体の製造》
ポリアミド樹脂アミランＣＭ−８０００（東レ社製）３０ｇをメタノール９００ｍｌ、１−ブタノール１００ｍｌの混合溶媒中に投入し５０℃で加熱溶解した。この液を外径６０ｍｍ、長さ３６０ｍｍの円筒状アルミニウム導電性支持体上に塗布し、０．５μｍ厚の中間層を形成した。
【０２９３】
次に、シリコーン樹脂ＫＲ−５２４０（信越化学社製）１０ｇを酢酸ｔ−ブチル１０００ｍｌに溶解し、これにＹ−ＴｉＯＰｃ（特開昭６４−１７０６６号記載、図１）１０ｇを混入しサンドミルを用いて２０時間分散し、電荷発生層塗工液を得た。この液を用いて、前記中間層上に塗布し、０．３μｍ厚の電荷発生層を形成した。
【０２９４】
次に、ＣＴＭ（Ｔ−１：Ｎ−（４−メチルフェニル）−Ｎ−｛４−（β−フェニルスチリル）フェニル｝−ｐ−トルイジン）１５０ｇと粘度平均分子量２万のポリカーボネート樹脂ユーピロンＺ−２００（三菱ガス化学社製）２００ｇを１、２−ジクロロエタン１０００ｍｌに溶解し、電荷輸送層塗工液を得た。この液を用いて、前記電荷発生層上に円形スライドホッパーにて塗布を行った後、１００℃で１時間乾燥し、２２μｍ厚の電荷輸送層を形成した。このようにして中間層、電荷発生層、電荷輸送層からなる感光体（Ｐ１）を得た。ついで、感光体試料（Ｐ１）の表面に、ＣＴＭ（Ｔ−１）３０ｇと粘度平均分子量８万のポリカーボネート樹脂ユーピロンＺ−８００（三菱ガス化学社製）ポリカーボネート樹脂５０ｇを１，２−ジクロロエタン１０００ｍｌに溶解した塗工液を用いて、前記電荷輸送層上に円形スライドホッパーにて塗布を行った後、１００℃で１時間乾燥し、５μｍ厚のオーバーコート層を形成し、感光体（Ｐ２）を得た。
【０２９５】
得られた感光体（Ｐ２）を市販のデジタル複写機コニカ Ｓｉｔｉｏｓ ７０３０に搭載した改造機を用いて、高温高湿環境下（温度３３℃、相対湿度８０％）において、画素率が１５％の画像を連続して３０万枚形成する実写テストを行ない、ブレード摩耗量、トナー粒子のすり抜け、画像ぼけ、画像濃度の環境依存性についての評価を行った。
【０２９６】
《ブレード摩耗量》
１０万枚印字後、クリーニングブレードをクリーニング装置より取り外し、レーザー顕微鏡で摩耗により消失した部分を測長した。減耗量２０μｍ以内であれば、問題ないレベルである（実用可）。
【０２９７】
《トナー粒子のすり抜け》
画像白地部にクリーニング装置から感光体上にトナーがすり抜け、画像汚れとして検知（目視評価）された枚数で評価した。
【０２９８】
《画像ぼけ》
画像全面に文字サイズ５ポイントの文字画像を形成し、局所的に画像がぼける、または、トナーが画像周辺に滲む部分が検知されるまでの枚数を目視により評価した。２０万枚以上が実用可である。
【０２９９】
《画像濃度の環境依存性》
マクベス反射濃度計にてソリッド画像部の最高画像濃度を測定した。高温高湿環境（３３℃、８０％ＲＨ）と低温低湿環境（１０℃、２０％ＲＨ）の画像濃度の差が０．０５未満を「◎」、０．０５〜０．１を「○」、０．１を超えるものを「×」とランク評価した。
【０３００】
得られた結果を表４に示す。
【０３０１】
【表４】

【０３０２】
表４から、比較と比べて本発明の試料は、クリーニングブレードの摩耗、トナー粒子のすり抜けが少なく、画像ぼけ、画像濃度の環境依存性も良好であることが明らかである。
【０３０３】
【発明の効果】
本発明により、画像形成時のクリーニング装置からのトナー粒子のすり抜けがなく、前記クリーニング装置のクリーニングブレードの摩耗量が低減され、画像ぼけがなく、且つ、形成された画像の画像濃度の環境依存性が小さい、静電荷像現像用トナー、その製造方法及び画像形成装置を提供することが出来た。
【図面の簡単な説明】
【図１】本発明に使用される定着装置（定着器）の一例を示す概略断面図である。
【図２】本発明に係る脂肪酸リチウム塩の製造に用いられる装置の一例を示す断面図である。
【図３】本発明の実施例１で作製されたステアリン酸リチウムの微粉末の粉末Ｘ線回折パターンを示す特性図である。
【図４】撹拌翼を備えた撹拌槽の一例の斜視図。
【図５】角のないトナー粒子を説明する概略図。
【符号の説明】
１ ジャケット
２ 攪拌槽
３ 回転軸
４、５ 攪拌翼
９ 邪魔板
α 攪拌翼間の交差角
８ 画像保持体
１０ 加熱ロール
１１ 加熱ロールの芯金
１２ 加熱ロールの被覆層
１３ 加熱部材
２０ 加圧ロール
２１ 加圧ロールの芯金
２２ 加圧ロールの被覆層
Ｔ トナー画像
１００ 容器
２００ 空洞部
３００ 穴
４００ 回転軸
５００ 軸受け
６００、７００ 攪拌羽
８００ 蓋[0001]
BACKGROUND OF THE INVENTION
The present invention relates to an electrostatic charge image developing toner, a method for producing the same, and an image forming apparatus.
[0002]
[Prior art]
Today, electrostatic latent image developing methods represented by electrophotography are widely used in image forming apparatuses such as printers, copying machines, and facsimiles.
[0003]
This is because it is a highly complete method for stably obtaining high-speed and high-quality images, but there are still some problems.
[0004]
For example, conventionally, in a toner prepared by a pulverization method, the material dispersed in the toner is unevenly present on the fracture surface, the surface property between the toners is not easily constant, and variations in the transfer process are likely to occur. There is a problem that the color reproducibility as a color image tends to deteriorate.
[0005]
On the other hand, the electrostatic latent image developing toner is desired to have a small particle size from the viewpoint of high image quality. In recent years, polymerization toner has been actively developed as a method for producing a small particle size toner. In this polymerization method, resin particles and, if necessary, colorant particles are associated or salted out, agglomerated, and fused to prepare an amorphous toner, or radically polymerizable monomer and colorant are dispersed. Then, there is a method in which droplets are dispersed in an aqueous medium or the like so as to have a desired toner particle size, and suspension polymerization is performed.
[0006]
However, since the toner particles produced by applying the suspension polymerization method are composed of a spherical surface or a curved surface, it is possible to form a toner having a uniform surface property, and the uniformity of charging between the toners is increased. The spherical shape of the particles increases the adhesion to the latent image carrier, and there is a problem that the cleaning tends to be lowered.
[0007]
In particular, in order to achieve high image quality, it is desirable to adjust the toner particles to have a small particle diameter and to make the shape of the toner particles uniform. There are problems such as slipping of toner particles from the cleaning device, large wear of the cleaning blade of the cleaning device, image blurring, and large environmental dependency of the image density of the formed image. The solution of the point was requested.
[0008]
[Problems to be solved by the invention]
It is an object of the present invention to prevent toner particles from slipping through a cleaning device during image formation, to reduce the amount of wear of the cleaning blade of the cleaning device, to prevent image blur, and to provide an image density environment for the formed image. It is an object to provide a toner for developing an electrostatic charge image, a method for producing the same, and an image forming apparatus with low dependency.
[0009]
[Means for Solving the Problems]
  The above objects of the present invention are the following items 1 to 1.16Achieved by.
[0010]
  1. In an electrostatic charge image developing toner having toner particles obtained by polymerizing a polymerizable monomer in an aqueous medium,TheThe toner has fatty acid lithium salt as at least one external additive.The fatty acid lithium salt has a water content of 0.1% by mass to 1.4% by mass, the fatty acid lithium salt has a free fatty acid content of 0.01% by mass to 0.7% by mass, and the toner particles However, it was manufactured through a process of agglomerating and fusing resin particles in an aqueous medium.An electrostatic charge image developing toner.
[0012]
  2.The fatty acid lithium salt is lithium stearate,1The toner for developing an electrostatic image according to the description.
[0014]
  3.Toner particles,As an external additive, it has inorganic / organic composite fine particles in which inorganic fine particles having a primary average particle size of 5 nm to 100 nm are fixed on the surface of organic fine particles having an average particle size of 0.1 μm to 5.0 μm. 1 aboveOr 2The toner for developing an electrostatic image according to the description.
[0015]
  4).The number average particle diameter of the toner particles is 2 μm to 8 μm, the variation coefficient of the shape factor is 16% or less, and the number variation coefficient in the number particle size distribution is 27% or less.~ 3The toner for developing an electrostatic image according to any one of the above.
[0016]
  5.The number average particle diameter of the toner particles is 2 μm to 8 μm, and the shape factor is in the range of 1.0 to 1.6.TheThe ratio of the toner particles to the total toner particles is 65% by number or more.~ 3The toner for developing an electrostatic image according to any one of the above.
[0017]
  6).The number average particle diameter of the toner particles is 2 μm to 8 μm, and the shape factor is in the range of 1.2 to 1.6.TheThe ratio of the toner particles to the total toner particles is 65% by number or more.~ 3The toner for developing an electrostatic image according to any one of the above.
[0018]
  7).The number average particle diameter of the toner particles is 2 μm to 8 μm, and there are no cornersTheThe ratio of the toner particles to the total toner particles is 50% by number or more.~ 6The toner for developing an electrostatic image according to any one of the above.
[0019]
  8).When the particle diameter of the toner particles is D (μm), the natural logarithm lnD is taken on the horizontal axis,TheIncluded in the most frequent class in the histogram showing the number-based particle size distribution with the horizontal axis divided into multiple classes at intervals of 0.23TheThe relative frequency (m1) of the toner particles;TheThe sum (M) with the relative frequency (m2) of the toner particles included in the next most frequent class after the most frequent class is 70% or more.~ 7The toner for developing an electrostatic image according to any one of the above.
[0020]
  9.The ratio of the toner particles having no corners to the total toner particles is 50% by number or more, and the number variation coefficient in the number particle size distribution is 27% or less.~ 8The toner for developing an electrostatic image according to any one of the above.
[0021]
  10.The ratio of the toner particles having a shape factor in the range of 1.2 to 1.6 to all toner particles is 65% by number or more,TheThe variation coefficient of the shape factor is 16% or less.~ 9The toner for developing an electrostatic image according to any one of the above.
[0022]
  11.The toner particles are produced through a step of salting out, aggregating and fusing the composite resin particles obtained by the multistage polymerization method and the colorant particles.-10The toner for developing an electrostatic charge image according to any one of the above.
[0023]
  12In the above GPC (gel permeation chromatography) measurement of toner, the peak or shoulder is present in at least 100,000 to 1,000,000 and 1,000 to 50,000.~ 11The toner for developing an electrostatic image according to any one of the above.
[0024]
  13.In the GPC (gel permeation chromatography) measurement of the toner, the peak or shoulder is present in at least 100,000 to 1,000,000, 25,000 to 100,000, and 1,000 to 25,000. Said 1~ 11The toner for developing an electrostatic charge image according to any one of the above.
[0025]
  14The electrostatic charge image formed on the organophotoreceptor is referred to as 1 above.~ 13And developing with a developer having the electrostatic charge image developing toner according to any one of the above,TheToner image visualized by developmentTheAfter being transferred from the organic photoreceptor to the transfer material, it remained on the organic photoreceptor.TheAn image forming apparatus comprising a cleaning device for removing toner.
[0026]
  15.Organic photoreceptor is photosensitive layer on conductive supportHaveAndTheThe surface layer of the photosensitive layer contains a polycarbonate having an average molecular weight of 40,000 or more.14The image forming apparatus described in 1.
[0027]
  16.1 above~ 13In producing the toner for developing an electrostatic charge image according to any one of the above, particles are formed in an aqueous medium,TheA method for producing a toner for developing an electrostatic charge image, wherein after the particles are dried, a fatty acid lithium salt is externally added in a range of 0.005% by mass to 0.3% by mass to produce toner particles.
[0028]
Hereinafter, the present invention will be described in detail.
In the present invention, in an electrostatic image developing toner having toner particles obtained by polymerizing a polymerizable monomer in an aqueous medium, the toner forms an image by using a fatty acid lithium salt as an external additive. An electrostatic charge image in which toner particles do not pass through the cleaning device at the time, the amount of wear of the cleaning blade of the cleaning device is reduced, there is no image blur, and the image density of the formed image is less dependent on the environment A developing toner, a manufacturing method thereof, and an image forming apparatus can be provided.
[0029]
The fatty acid lithium salt according to the present invention will be described.
Specifically, the fatty acid lithium salt according to the present invention used as an external additive includes lithium undecylate, lithium laurate, lithium tridecylate, lithium dodecylate, lithium myristate, lithium palmitate, lithium pentadecylate, stearin Long chain fatty acid lithium, such as lithium acid lithium, lithium behenate, lithium heptadecylate, lithium arachidate, lithium montanate, lithium oleate, lithium linoleate, lithium arachidate, lithium behenate, and the like.
[0030]
Among these, lithium stearate is particularly preferably used in the present invention.
[0031]
The fatty acid portion of the fatty acid lithium salt according to the present invention may have a single fatty acid configuration or a mixed fatty acid configuration.
[0032]
As the method for producing a fatty acid lithium salt according to the present invention, any of the following methods may be used.
[0033]
Production method (1): A solid lithium salt and a solid higher fatty acid wetted with water are used as raw materials, and the solid phase reaction between the lithium salt and the higher fatty acids can be maintained in a sealed space. The raw material is reacted so that the generated carbon dioxide gas does not escape to the outside during the heating and stirring to obtain a fatty acid lithium salt.
[0034]
Production method (2): After adding water corresponding to 2.5 times the amount of fatty acid to lithium carbonate, keeping the liquid temperature at 80 ° C., and adding the fatty acid melted in advance while stirring this liquid To obtain a fatty acid lithium salt.
[0035]
The particle diameter of the fatty acid lithium salt according to the present invention is preferably 99% with a mesh passage of 75 μm openings from the viewpoint of obtaining good cleaning properties. From the viewpoint of improving humidity stability during charging and preventing image blurring, the water content of the fatty acid lithium salt according to the present invention is preferably 0.1% by mass to 1.4% by mass, particularly preferably. 0.3 mass% to 1.2 mass%.
[0036]
Here, the moisture content is measured by the Karl Fischer method.
Further, from the viewpoint of preventing contamination of charging members such as carriers and developing rolls, and appropriately preventing abrasion of the cleaning blade, the amount of free fatty acid in the toner of the present invention is preferably 0.01% by mass to 0.9% by mass, Especially preferably, it is 0.05 mass%-0.6 mass%.
[0037]
The free fatty acid in the toner of the present invention is present in the toner without the fatty acid contained in the fatty acid lithium salt added and mixed as the additive in the toner particle production process adhering to the toner particle surface. It is what.
[0038]
Further, in order to disperse in the toner and improve the charging stability, a fatty acid lithium salt having an average particle diameter of 4 μm or less and particles larger than 10 μm is 4% by mass or less in the fatty acid lithium salt is used. preferable.
[0039]
The addition amount of the fatty acid lithium salt according to the present invention to the toner is preferably about 0.1 to 5% by mass with respect to the toner.
[0040]
The inorganic / organic composite fine particles used in the present invention will be described.
In the present invention, inorganic / organic composite fine particles are preferably used as the abrasive particles. The inorganic / organic composite fine particles have a spherical shape, the surface is a hard inorganic fine powder, and the core uses organic elastic particles that are relatively elastic. Stable cleaning performance is exhibited without causing scratches on the photoreceptor or the cleaning blade.
[0041]
The primary average particle diameter of the inorganic fine particles constituting the inorganic / organic composite fine particles is preferably 5 nm to 100 nm, and more preferably 10 nm to 65 nm, from the viewpoint of improving cleaning properties, polishing properties, and filming resistance. The primary average particle diameter of the inorganic fine particles refers to a number-based average particle diameter measured by an image analyzer when observed with a scanning electron microscope.
[0042]
Constituent materials of inorganic fine particles include silicon oxide, titanium oxide, aluminum oxide, zinc oxide, zirconium oxide, cerium oxide, tungsten oxide, antimony oxide, copper oxide, tellurium oxide, manganese oxide, barium titanate, strontium titanate, titanium Magnesium acid, silicon nitride, carbon nitride and the like are used.
[0043]
The organic fine particles constituting the inorganic / organic composite fine particles are preferably resin particles made of an acrylic polymer, a styrene polymer, a styrene-acrylic polymer, or the like.
[0044]
The acrylic polymer constituting the organic fine particles is a homopolymer or copolymer obtained by polymerizing a monomer selected from acrylic acid or acrylic ester, methacrylic acid or methacrylic ester. Examples of acrylic monomers used to obtain such acrylic polymers include acrylic acid, methyl acrylate, ethyl acrylate, n-butyl acrylate, isobutyl acrylate, propyl acrylate, n-octyl acrylate, Dodecyl acrylate, lauryl acrylate, 2-ethylhexyl acrylate, stearyl acrylate, 2-chloroethyl acrylate, phenyl acrylate, methyl α-chloroacrylate, methacrylic acid, methyl methacrylate, ethyl methacrylate, propyl methacrylate, N-butyl methacrylate, isobutyl methacrylate, n-octyl methacrylate, dodecyl methacrylate, lauryl methacrylate, 2-ethylhexyl methacrylate, stearyl methacrylate, phenyl methacrylate, dimethyl methacrylate Minoechiru, and diethylaminoethyl methacrylate, and the like
Styrene monomers include styrene, o-methylstyrene, m-methylstyrene, p-methylstyrene, α-methylstyrene, p-ethylstyrene, 2,4-dimethylstyrene, pn-butylstyrene, p -Tert-butyl styrene, pn-hexyl styrene, pn-octyl styrene, pn-nonyl styrene, pn-decyl styrene, pn-dodecyl styrene, p-methoxy styrene, p-phenyl styrene , P-chlorostyrene, 3,4-dichlorostyrene and the like. A styrene polymer can be obtained from one or more of the above styrene monomers. In the present invention, one or more other monomers are copolymerized as required. There may be. In this case, it is preferable to use a styrene monomer in the monomer composition in a proportion of 50% by mass or more.
[0045]
The styrene-acrylic copolymer constituting the organic fine particles can be obtained from one or more of the acrylic monomers and one or more of the styrenic monomers. In addition, one or two or more types of other monomers may be copolymerized. In this case, in the monomer composition, the total of the acrylic monomer and the styrene monomer is preferably used at a ratio of 50% by mass or more. Examples of the other monomers include acrylic acid or methacrylic acid derivatives such as acrylonitrile, methacrylonitrile and acrylamide, vinyl esters such as vinyl acetate, vinyl butyrate and vinyl benzoate, and vinyl ethers such as vinyl methyl ether and vinyl ethyl ether. , Vinyl ketones such as vinyl methyl ketone, dienes such as butadiene and isoprene, unsaturated carboxylic acids such as maleic acid and fumaric acid, and the like.
[0046]
The average particle diameter of the organic fine particles constituting the inorganic / organic composite fine particles is preferably 0.1 μm to 5.0 μm, particularly preferably 0.2 μm to 3.0 μm, from the viewpoints of improvement in cleaning properties and stability of tribocharging properties. . The average particle size of the organic fine particles is a volume-based average particle size measured by a laser diffraction particle size distribution measuring apparatus “HELOS” (manufactured by SYMPATEC) equipped with a wet disperser. . However, before the measurement, 10 mg of organic fine particles were dispersed in 50 ml of water together with a surfactant, and then pretreatment was performed with an ultrasonic homogenizer (output 150 W) for 1 to 10 minutes while paying attention to re-aggregation due to heat generation.
[0047]
The inorganic / organic composite fine particles are constituted by fixing inorganic fine particles treated with the specific treatment compound on the surface of the organic fine particles. Here, the term “fixation” refers to a state in which the inorganic fine particles are not simply attached to the organic fine particles by electrostatic force but the length of the portion embedded in the organic fine particles is 5 to 95%. Such a state can be confirmed by observing the surface of the inorganic / organic composite fine particles with a transmission electron microscope or a normal electron microscope. When fixing the inorganic fine particles to the surface of the organic fine particles, it is preferable to first spheroidize the organic fine particles and then fix the inorganic fine particles to the surface of the organic fine particles. This is because when the organic fine particles are spherical, the inorganic fine particles are fixed uniformly and the release of the inorganic fine particles is effectively prevented. As a means for spheroidizing organic fine particles, a method in which organic fine particles are once melted by heat and then spray granulation is performed, a method in which heat-melted organic fine particles are discharged into water by jetting, a suspension polymerization method or And a method of synthesizing spherical organic fine particles by an emulsion polymerization method.
[0048]
As means for fixing inorganic fine particles to the surface of organic fine particles, there are a method of mixing organic fine particles and inorganic fine particles and then applying heat, a so-called mechanochemical method of mechanically fixing inorganic fine particles to the surface of organic fine particles, etc. Used. Specifically, organic fine particles and inorganic fine particles are mixed and mixed by stirring with a Henschel mixer, a V-type mixer, a turbuler mixer, etc., and the inorganic fine particles are adhered to the surface of the organic fine particles by electrostatic force, and then the surface is inorganic. A method in which organic fine particles with fine particles attached are introduced into a heat treatment device such as a nilo atomizer or a spray dryer, and the surface of the organic fine particles is softened by applying heat to fix the inorganic fine particles to the surface. After attaching the inorganic fine particles, the inorganic fine particles are fixed to the surface of the organic fine particles using a device capable of applying mechanical energy by modifying the impact pulverizer, such as an ang mill, a free mill, or a hybridizer. Or the like.
[0049]
In obtaining the inorganic / organic composite fine particles, the amount of the inorganic fine particles mixed with the organic fine particles may be an amount that can uniformly cover the surface of the organic fine particles. Specifically, although depending on the specific gravity of the inorganic fine particles, the inorganic fine particles are generally used in a proportion of 5 to 100% by mass, preferably 5 to 80% by mass with respect to the organic fine particles. If the proportion of the inorganic fine particles is too small, the cleaning property tends to be lowered. Conversely, if the proportion of the inorganic fine particles is too large, the inorganic fine particles are likely to be liberated.
[0050]
The above inorganic / organic composite fine particles are added to and mixed with the colored particles to constitute a toner. The blending ratio of the inorganic / organic composite fine particles is different from that of the colored particles from the viewpoint of improving the cleaning property and the stability of the triboelectric charging property. On the other hand, 0.01-5.0 mass% is preferable, and 0.01-2.0 mass% is particularly preferable.
[0051]
The abrasive other than the inorganic / organic composite fine particles used in the present invention will be described.
Examples of externally added abrasives include lithium titanate powder, barium titanate powder, magnesium titanate powder, strontium titanate powder, cerium oxide powder, zirconium oxide powder, titanium oxide powder, aluminum oxide powder, boron carbide powder, There are silicon carbide powder, silicon oxide powder, diamond powder and the like, which are used alone or in combination. Of these, strontium titanate powder and cerium oxide powder are particularly preferably used.
[0052]
In the present invention, the amount of the abrasive is preferably 0.1 to 10.0 parts by mass, more preferably 0.2 to 5.0 parts by mass with respect to 100 parts by mass of the toner particles.
[0053]
The binder resin constituting the electrostatic image developing toner of the present invention will be described.
The binder resin that is a constituent component of the toner particles according to the present invention is produced using resin particles obtained by polymerizing a polymerizable monomer in an aqueous medium.
[0054]
Here, as a polymerizable monomer used for preparation of the resin particles, styrene, o-methylstyrene, m-methylstyrene, p-methylstyrene, α-methylstyrene, p-chlorostyrene, 3,4-dichloro Styrene, p-phenylstyrene, p-ethylstyrene, 2,4-dimethylstyrene, p-tert-butylstyrene, pn-hexylstyrene, pn-octylstyrene, pn-nonylstyrene, pn -Styrene or styrene derivatives such as decylstyrene, pn-dodecylstyrene, methyl methacrylate, ethyl methacrylate, n-butyl methacrylate, isopropyl methacrylate, isobutyl methacrylate, t-butyl methacrylate, n-methacrylate Octyl, 2-ethylhexyl methacrylate, stear methacrylate Methacrylic acid ester derivatives such as lauryl methacrylate, phenyl methacrylate, diethylaminoethyl methacrylate, dimethylaminoethyl methacrylate, methyl acrylate, ethyl acrylate, isopropyl acrylate, n-butyl acrylate, t-butyl acrylate , Isobutyl acrylate, n-octyl acrylate, 2-ethylhexyl acrylate, stearyl acrylate, lauryl acrylate, phenyl acrylate, etc., acrylate derivatives, ethylene, propylene, isobutylene olefins, vinyl chloride, chloride Halogenated vinyls such as vinylidene, vinyl bromide, vinyl fluoride, vinylidene fluoride, vinyl esters such as vinyl propionate, vinyl acetate, vinyl benzoate, vinyl methyl ether, vinyl ethyl Vinyl ethers such as ether, vinyl ketones such as vinyl methyl ketone, vinyl ethyl ketone, vinyl hexyl ketone, N-vinyl compounds such as N-vinyl carbazole, N-vinyl indole, N-vinyl pyrrolidone, vinyl naphthalene, vinyl pyridine, etc. There are acrylic acid or methacrylic acid derivatives such as vinyl compounds, acrylonitrile, methacrylonitrile, acrylamide and the like. These vinyl monomers can be used alone or in combination.
[0055]
Further, it is more preferable to use a combination of monomers having an ionic dissociation group as the polymerizable monomer constituting the resin. For example, it has a substituent such as a carboxyl group, a sulfonic acid group, a phosphoric acid group as a constituent group of the monomer, specifically, acrylic acid, methacrylic acid, maleic acid, itaconic acid, cinnamic acid, fumar Acid, maleic acid monoalkyl ester, itaconic acid monoalkyl ester, styrene sulfonic acid, allyl sulfosuccinic acid, 2-acrylamido-2-methylpropane sulfonic acid, acid phosphooxyethyl methacrylate, 3-chloro-2-acid phosphooxy And propyl methacrylate. Furthermore, polyfunctionality such as divinylbenzene, ethylene glycol dimethacrylate, ethylene glycol diacrylate, diethylene glycol dimethacrylate, diethylene glycol diacrylate, triethylene glycol dimethacrylate, triethylene glycol diacrylate, neopentyl glycol dimethacrylate, neopentyl glycol diacrylate, etc. It is also possible to use a crosslinkable resin by using a functional vinyl.
[0056]
These polymerizable monomers can be polymerized using a radical polymerization initiator. In this case, an oil-soluble polymerization initiator can be used in the suspension polymerization method. Examples of the oil-soluble polymerization initiator include 2,2′-azobis- (2,4-dimethylvaleronitrile), 2,2′-azobisisobutyronitrile, 1,1′-azobis (cyclohexane-1-carboxyl). Nitriles), 2,2'-azobis-4-methoxy-2,4-dimethylvaleronitrile, azo- or diazo-based polymerization initiators such as azobisisobutyronitrile, benzoyl peroxide, methyl ethyl ketone peroxide, diisopropyl peroxycarbonate , Cumene hydroperoxide, t-butyl hydroperoxide, di-t-butyl peroxide, dicumyl peroxide, 2,4-dichlorobenzoyl peroxide, lauroyl peroxide, 2,2-bis- (4,4- t-butylperoxycyclohexyl) propane, tris The (t-butylperoxy) triazine peroxide polymerization initiator or a peroxide, such as and the like polymeric initiator having a side chain. Moreover, when using an emulsion polymerization method, a water-soluble radical polymerization initiator can be used. Examples of the water-soluble polymerization initiator include persulfates such as potassium persulfate and ammonium persulfate, azobisaminodipropane acetate, azobiscyanovaleric acid and its salts, hydrogen peroxide and the like.
[0057]
Dispersion stabilizers include trilithium phosphate, magnesium phosphate, zinc phosphate, aluminum phosphate, lithium carbonate, magnesium carbonate, lithium hydroxide, magnesium hydroxide, aluminum hydroxide, lithium metasilicate, lithium sulfate, barium sulfate , Bentonite, silica, alumina and the like. Furthermore, those generally used as surfactants such as polyvinyl alcohol, gelatin, methylcellulose, sodium dodecylbenzenesulfonate, ethylene oxide adduct, and higher alcohol sodium sulfate can be used as the dispersion stabilizer.
[0058]
As the resin excellent in the present invention, those having a glass transition point of 20 to 90 ° C. are preferred, and those having a softening point of 80 to 220 ° C. are preferred. The glass transition point is measured by a differential calorimetric analysis method, and the softening point can be measured by a Koka flow tester.
[0059]
Further, as these resins, it is preferable that peaks or shoulders exist in at least 100,000 to 1,000,000 and 1,000 to 50,000, more preferably, in GPC (gel permeation chromatography) measurement. In GPC (gel permeation chromatography) measurement, peaks or shoulders are present at least at 100,000 to 1,000,000, 25,000 to 100,000, and 1,000 to 25,000.
[0060]
In the measurement by GPC measurement of the above-mentioned resin, a chromatogram can be obtained by measuring the solution after dissolving the toner in a solvent such as THF and filtering the dust.
[0061]
The colorant according to the present invention will be described.
The toner of the present invention is obtained by salting out / fusion-bonding the composite resin particles and the colorant particles. Examples of the colorant constituting the toner of the present invention (colorant particles used for salting out / fusion with composite resin particles) include various inorganic pigments, organic pigments, and dyes. A conventionally well-known thing can be used as an inorganic pigment. Specific inorganic pigments are exemplified below.
[0062]
Examples of the black pigment include carbon black such as furnace black, channel black, acetylene black, thermal black, and lamp black, and magnetic powder such as magnetite and ferrite.
[0063]
These inorganic pigments can be used alone or in combination as required. Moreover, the addition amount of a pigment is 2-20 mass% with respect to a polymer, Preferably 3-15 mass% is selected.
[0064]
When used as a magnetic toner, the above-mentioned magnetite can be added. In this case, it is preferable to add 20 to 120% by mass in the toner from the viewpoint of imparting predetermined magnetic properties.
[0065]
Conventionally known organic pigments and dyes can also be used. Specific organic pigments and dyes are exemplified below.
[0066]
Examples of the magenta or red pigment include C.I. I. Pigment red 2, C.I. I. Pigment red 3, C.I. I. Pigment red 5, C.I. I. Pigment red 6, C.I. I. Pigment red 7, C.I. I. Pigment red 15, C.I. I. Pigment red 16, C.I. I. Pigment red 48: 1, C.I. I. Pigment red 53: 1, C.I. I. Pigment red 57: 1, C.I. I. Pigment red 122, C.I. I. Pigment red 123, C.I. I. Pigment red 139, C.I. I. Pigment red 144, C.I. I. Pigment red 149, C.I. I. Pigment red 166, C.I. I. Pigment red 177, C.I. I. Pigment red 178, C.I. I. And CI Pigment Red 222.
[0067]
Examples of the pigment for orange or yellow include C.I. I. Pigment orange 31, C.I. I. Pigment orange 43, C.I. I. Pigment yellow 12, C.I. I. Pigment yellow 13, C.I. I. Pigment yellow 14, C.I. I. Pigment yellow 15, C.I. I. Pigment yellow 17, C.I. I. Pigment yellow 93, C.I. I. Pigment yellow 94, C.I. I. Pigment yellow 138, C.I. I. Pigment yellow 180, C.I. I. Pigment yellow 185, C.I. I. Pigment yellow 155, C.I. I. And CI Pigment Yellow 156.
[0068]
Examples of the pigment for green or cyan include C.I. I. Pigment blue 15, C.I. I. Pigment blue 15: 2, C.I. I. Pigment blue 15: 3, C.I. I. Pigment blue 16, C.I. I. Pigment blue 60, C.I. I. And CI Pigment Green 7.
[0069]
Examples of the dye include C.I. I. Solvent Red 1, 49, 52, 58, 63, 111, 122, C.I. I. Solvent Yellow 19, 44, 77, 79, 81, 82, 93, 98, 103, 104, 112, 162, C.I. I. Solvent Blue 25, 36, 60, 70, 93, 95, etc. can be used, and mixtures thereof can also be used.
[0070]
These organic pigments and dyes can be used alone or in combination as required. Moreover, the addition amount of a pigment is 2-20 mass% with respect to a polymer, Preferably 3-15 mass% is selected.
[0071]
The colorant (colorant particles) constituting the toner of the present invention may be surface-modified. A conventionally well-known thing can be used as a surface modifier, Specifically, a silane coupling agent, a titanium coupling agent, an aluminum coupling agent etc. can be used preferably. Examples of the silane coupling agent include alkoxysilanes such as methyltrimethoxysilane, phenyltrimethoxysilane, methylphenyldimethoxysilane, and diphenyldimethoxysilane, siloxanes such as hexamethyldisiloxane, γ-chloropropyltrimethoxysilane, vinyltrimethyl. Chlorosilane, vinyltrimethoxysilane, vinyltriethoxysilane, γ-methacryloxypropyltrimethoxysilane, γ-glycidoxypropyltrimethoxysilane, γ-mercaptopropyltrimethoxysilane, γ-aminopropyltriethoxysilane, γ-ureido Examples thereof include propyltriethoxysilane. Examples of titanium coupling agents include TTS, 9S, 38S, 41B, 46B, 55, 138S, and 238S, which are commercially available under the trade name “Plenact” manufactured by Ajinomoto Co., Inc. -1, B-1, TOT, TST, TAA, TAT, TLA, TOG, TBSTA, A-10, TBT, B-2, B-4, B-7, B-10, TBSTA-400, TTS, TOA -30, TSDMA, TTAB, TTOP and the like. Examples of the aluminum coupling agent include “Plenact AL-M” manufactured by Ajinomoto Co., Inc.
[0072]
The addition amount of these surface modifiers is preferably 0.01 to 20% by mass, and more preferably 0.1 to 5% by mass with respect to the colorant.
[0073]
Examples of the method for modifying the surface of the colorant particles include a method in which a surface modifier is added to the dispersion of the colorant particles and this system is heated to react.
[0074]
The surface-modified colorant particles are collected by filtration, washed with the same solvent and filtered, and then dried.
[0075]
The release agent used for the toner of the present invention will be described.
The toner used in the present invention is preferably a toner obtained by fusing resin particles encapsulating a release agent in an aqueous medium. In this way, the resin particles in which the release agent is encapsulated in the resin particles are salted out / fused in the aqueous medium with the colorant particles, whereby a toner in which the release agent is finely dispersed can be obtained.
[0076]
In the toner of the present invention, low molecular weight polypropylene (number average molecular weight = 1500 to 9000), low molecular weight polyethylene, and the like are preferable as the release agent, and ester compounds represented by the following formula are particularly preferable.
[0077]
R¹-(OCO-R²)_n
In the formula, n is an integer of 1 to 4, preferably 2 to 4, more preferably 3 to 4, particularly preferably 4. R¹, R²Each represents a hydrocarbon group which may have a substituent. R¹Has 1 to 40 carbon atoms, preferably 1 to 20 carbon atoms, more preferably 2 to 5 carbon atoms. R²Has 1 to 40 carbon atoms, preferably 16 to 30 carbon atoms, and more preferably 18 to 26 carbon atoms.
[0078]
Next, examples of typical compounds are shown below.
[0079]
[Chemical 1]

[0080]
[Chemical formula 2]

[0081]
The amount of the compound added is 1 to 30% by mass, preferably 2 to 20% by mass, and more preferably 3 to 15% by mass with respect to the whole toner.
[0082]
The toner of the present invention is preferably prepared by encapsulating the release agent in resin particles by a mini-emulsion polymerization method, and salting out and fusing together with colored particles.
[0083]
The physical characteristics, number average particle size, variation coefficient of shape factor, number variation coefficient in the number particle size distribution, shape factor, and the like of the toner particles according to the present invention will be described.
[0084]
The particle size of the toner of the present invention is preferably 2 μm to 10 μm, more preferably 2 μm to 8 μm, in terms of number average particle size. This particle size can be controlled by the concentration of the flocculant (salting-out agent), the amount of organic solvent added, the fusing time, and the polymer composition in the toner production method.
[0085]
By adjusting the number average particle size to 3 to 10 μm, in the fixing process, toner particles with high adhesion force that fly and adhere to the heating member and generate offset are reduced, and transfer efficiency is increased and half The image quality of the tone is improved, and the image quality of fine lines and dots can be improved.
[0086]
The number average particle diameter of the toner can be measured using a Coulter Counter TA-II, Coulter Multisizer, SLAD 1100 (Laser Diffraction Particle Size Measuring Device manufactured by Shimadzu Corporation) or the like.
[0087]
In the present invention, a Coulter Multisizer is used, and an interface (manufactured by Nikka Machine Co., Ltd.) that outputs a particle size distribution and a personal computer are connected. The aperture in the Coulter Multisizer was 100 μm, and the volume distribution of toner of 2 μm or more (for example, 2 to 40 μm) was measured to calculate the particle size distribution and average particle size.
[0088]
The shape factor of the toner particles of the present invention will be described.
The shape factor of the toner of the present invention is represented by the following formula and indicates the degree of roundness of the toner particles.
[0089]
Shape factor = ((maximum diameter / 2)²× π) / projection area
Here, the maximum diameter refers to the width of a particle that maximizes the interval between the parallel lines when the projected image of the toner particles on the plane is sandwiched between two parallel lines. The projected area refers to the area of the projected image of the toner particles on the plane.
[0090]
In the present invention, this shape factor is obtained by taking a photograph in which the toner particles are magnified 2000 times with a scanning electron microscope, and then using “SCANNING IMAGE ANALYZER” (manufactured by JEOL Ltd.) based on this photograph. It was measured by performing analysis. At this time, the shape factor of the present invention was measured by the above formula using 100 toner particles.
[0091]
The variation coefficient of the shape factor of the toner according to the present invention will be described.
The “shape coefficient variation coefficient” of the toner is calculated from the following equation.
[0092]
Variation coefficient of toner shape factor = (S1 / K) × 100 (%)
In the formula, S1 represents the standard deviation of the shape factor of 100 toner particles, and K represents the average value of the shape factor.
[0093]
The number particle size distribution and the number variation coefficient of the toner according to the present invention will be described.
The number particle size distribution and the number variation coefficient of the toner are measured with a Coulter Counter TA-II or Coulter Multisizer (manufactured by Coulter Inc.). In the present invention, a Coulter Multisizer is used, and an interface (manufactured by Nikkaki Co., Ltd.) that outputs a particle size distribution and a personal computer are connected.
[0094]
The number particle size distribution represents the relative frequency of the toner particles with respect to the particle size, and the number average particle size represents the median diameter in the number particle size distribution. The “number variation coefficient in the number particle size distribution” of the toner (hereinafter referred to as the toner number variation coefficient) is calculated from the following equation.
[0095]
Toner number variation coefficient = (S2 / Dn) × 100 (%)
In the formula, S2 represents the standard deviation in the number particle size distribution, and Dn represents the number average particle size (μm).
[0096]
The number average particle diameter of the toner particles is 2 μm to 8 μm, the variation coefficient of the shape coefficient is 16% or less, and the number variation coefficient in the number particle size distribution is adjusted to 27% or less. Thus, the toner of the present invention can more preferably exhibit the effects described in the present invention.
[0097]
By using a toner having a variation factor of 16% or less in shape factor, the effect described by the effect of the shape factor is more remarkably exhibited, but a more preferable variation factor of the shape factor is 14% or less.
[0098]
The number variation coefficient of the toner according to claim 6 is 27% or less, preferably 25% or less. When the number variation coefficient is 27% or less, the charge amount distribution becomes sharp, the transfer efficiency is increased, and the image quality is improved. When such a toner is used in the image forming apparatus of the present invention, the charging property of the toner is stabilized, cleaning failure is unlikely to occur, and the surface of the photoreceptor having the above-described siloxane-based resin layer can always be kept clean. .
[0099]
The method for controlling the number variation coefficient in the toner is not particularly limited. For example, a method of classifying toner particles by wind force can be used, but classification in liquid is effective in order to reduce the number variation coefficient. As a method of classifying in this liquid, there is a method of separating and collecting toner particles according to a difference in sedimentation speed caused by a difference in toner particle diameter by using a centrifuge and controlling the rotation speed.
[0100]
In particular, when a toner is produced by a suspension polymerization method, a classification operation is indispensable in order to make the number variation coefficient in the number particle size distribution 27% or less. In the suspension polymerization method, it is necessary to disperse a polymerizable monomer in an oil droplet having a desired size as a toner in an aqueous medium before polymerization. That is, mechanical shearing with a homomixer or homogenizer is repeated for large oil droplets of a polymerizable monomer to reduce the oil droplets to the size of toner particles. In the method using shearing, the number particle size distribution of the obtained oil droplets is wide, and therefore the particle size distribution of the toner obtained by polymerizing the oil droplets is also wide. For this reason, classification operation is essential.
[0101]
Further, in order to uniformly control the shape factor of the toner and the coefficient of variation of the shape factor without variation in lots, the resin particles (polymer particles) constituting the toner of the present invention are prepared (polymerized), and the resin particles are In the process of fusing and shape control, an appropriate process end time may be determined while monitoring the characteristics of the toner particles (colored particles) being formed.
[0102]
Monitoring means that a measuring device is incorporated in-line, and process conditions are controlled based on the measurement result. That is, in the case of polymerization toner formed by incorporating shape measurement in-line, for example, by associating or fusing resin particles in an aqueous medium, the shape and particle size are sequentially sampled during the fusing process. The reaction is stopped when the desired shape is obtained.
[0103]
Although it does not specifically limit as a monitoring method, The flow type particle image analyzer FPIA-2000 (made by Toa Medical Electronics Co., Ltd.) can be used. This apparatus is suitable because the shape can be monitored by performing image processing in real time while passing the sample liquid. That is, a pump or the like is used from the reaction field, and the shape is measured continuously, and the reaction is stopped when the desired shape is obtained.
[0104]
The number average particle diameter of the toner particles may be 2 μm to 8 μm, and the toner particles having a shape factor in the range of 1.0 to 1.6 may be 65% by number or more. More preferably, it is 70% by number or more.
[0105]
More preferably, as described in claim 8, the number average particle diameter of the toner particles is 2 μm to 8 μm and the toner particles having a shape factor in the range of 1.2 to 1.6 are 65% by number or more. More preferably, it is 70% by number or more.
[0106]
Further, as described in claim 12, the number of toner particles having a shape factor in the range of 1.2 to 1.6 is 65% by number or more, and the variation coefficient of the shape factor is adjusted to 16% or less. It has also been found that stable developability and fine line reproducibility can be formed over a long period of time.
[0107]
As for the shape factor, when the number of toner particles having a numerical value in the range of 1.0 to 1.6 is 65% by number or more, the triboelectric chargeability on the developer conveying member becomes more uniform and excessively charged. Since there is no accumulated toner and the toner is more easily exchanged from the surface of the developer conveying member, problems such as development ghost are less likely to occur. Further, the toner particles are less likely to be crushed, the contamination of the charging member is reduced, and effects such as stabilization of the toner charging property can be obtained.
[0108]
The method for controlling the shape factor is not particularly limited. For example, a method in which toner particles are sprayed into a hot air stream, a method in which toner particles are repeatedly applied with mechanical energy due to impact force in a gas phase, or a method in which a toner is not dissolved in a solvent and a swirl flow is applied. To adjust the toner having a shape factor of 1.0 to 1.6 or 1.2 to 1.6, and add the toner into a normal toner so as to be within the range of the present invention. There is. In addition, the overall shape is controlled at the stage of preparing a so-called polymerization method toner, and a toner whose shape factor is adjusted to 1.0 to 1.6 or 1.2 to 1.6 is similarly added to a normal toner. There is a way to adjust.
[0109]
In the toner of the present invention, when the particle diameter of the toner particles is D (μm), the natural logarithm lnD is taken on the horizontal axis, and the horizontal axis is divided into a plurality of classes at intervals of 0.23. In the histogram showing the distribution, the sum (M) of the relative frequency (m1) of the toner particles contained in the most frequent class and the relative frequency (m2) of the toner particles contained in the next most frequent class after the most frequent class. The toner is preferably 70% or more.
[0110]
When the sum (M) of the relative frequency (m1) and the relative frequency (m2) is 70% or more, the dispersion of the particle size distribution of the toner particles becomes narrow. Therefore, selective development can be performed by using the toner in the image forming process. Can be reliably suppressed.
[0111]
In the present invention, the histogram showing the particle size distribution based on the number is a natural logarithm lnD (D: particle size of individual toner particles) having a plurality of classes (0 to 0.23: 0.23) at intervals of 0.23. 0.46: 0.46-0.69: 0.69-0.92: 0.92-1.15: 1.15-1.38: 1.38-1.61: 1.61-1. 84: 1.84 to 2.07: 2.07 to 2.30: 2.30 to 2.53: 2.53 to 2.76, and so on). This histogram was created by transferring the particle size data of the sample measured by the Coulter Multisizer to the computer via the I / O unit according to the following conditions and using the particle size distribution analysis program in the computer. is there.
[0112]
〔Measurement condition〕
1: Aperture: 100 μm
2: Sample preparation method: electrolytic solution [ISOTON R-11 (manufactured by Coulter Scientific Japan)] 50-100 ml, an appropriate amount of a surfactant (neutral detergent) was added and stirred, and 10-20 mg of a measurement sample was added thereto. Add. This system is prepared by dispersing for 1 minute with an ultrasonic disperser.
[0113]
Furthermore, as a result of investigations by paying attention to the minute shape of each toner particle, the present inventors have changed the shape of the corner portion of the toner particle to become round inside the developing device, and this portion has a blade wear. It was found that it was generated. The reason for this is not clear, but it is estimated that stress is easily applied to the corner portion and promotes blade wear in this portion. In addition, when charge is applied to the toner particles by frictional charging, it is presumed that the charge tends to concentrate particularly at the corners, and the toner particles are likely to be non-uniformly charged.
[0114]
That is, by using toner composed of toner particles in which the number of toner particles having no corners is 50% by number or more and the number variation coefficient in the number particle size distribution is controlled to 27% or less, developability and fine line reproduction are also achieved. It has been found that an image with excellent properties and high image quality can be formed over a long period of time.
[0115]
The “toner particles without corners” according to the present invention will be described with reference to FIG.
In the toner according to the present invention, the proportion of toner particles having no corners in the toner particles constituting the toner is preferably 50% by number or more, and more preferably 70% by number or more.
[0116]
When the ratio of the toner particles having no corners is 50% by number or more, voids in the transferred toner layer (powder layer) are reduced, fixing property is improved, and offset is hardly generated. In addition, toner particles that easily wear and break and toner particles having a portion where charges are concentrated are reduced, the charge amount distribution becomes sharp, the chargeability is stable, and good image quality can be formed over a long period of time.
[0117]
Here, the “toner particles having no corners” means toner particles having substantially no protrusions that concentrate electric charges or protrusions that easily wear due to stress. Specifically, the following toner particles are used. Is called toner particles having no corners. That is, as shown in FIG. 5A, when the major axis of the toner particles T is L, a circle C having a radius (L / 10) is in contact with the peripheral line of the toner particles T at one point. A case where the circle C does not substantially protrude outside the toner T when the inner side is rolled is referred to as “toner particles having no corners”. “A case where the protrusion does not substantially protrude” refers to a case where the protrusion having the protruding circle is one or less. The “major diameter of toner particles” refers to the width of a particle that maximizes the interval between the parallel lines when the projected image of the toner particles on a plane is sandwiched between two parallel lines. 5B and 5C show projection images of toner particles having corners, respectively.
[0118]
The ratio of toner particles having no corners was measured as follows. First, an enlarged photograph of the toner particles is taken with a scanning electron microscope, and further enlarged to obtain a 15,000 times photographic image. The photographic image is then measured for the presence or absence of the corners. This measurement was performed on 100 toner particles.
[0119]
A method for obtaining toner having no corners is not particularly limited. For example, as described above as a method for controlling the shape factor, a method in which toner particles are sprayed into a hot air stream, a method in which toner particles are repeatedly applied with mechanical energy by impact force in a gas phase, or a toner is dissolved. It can be obtained by adding in a solvent that does not, and applying a swirling flow.
[0120]
A method for producing the toner of the present invention will be described.
In the toner of the present invention, fine resin particles are prepared by suspension polymerization or emulsion polymerization of a monomer or mini-emulsion polymerization in a liquid (in an aqueous medium) to which an emulsion of necessary additives is added. Then, the charge controllable resin particles of the present invention can be added, and then the resin particles can be aggregated and fused by adding an aggregating agent such as an organic solvent or salts.
[0121]
An example of a method for producing the toner of the present invention is to dissolve a charge control resin in a polymerizable monomer, and add various constituent materials such as a colorant, a release agent as required, and a polymerization initiator. Then, various constituent materials are dissolved or dispersed in the polymerizable monomer using a homogenizer, a sand mill, a sand grinder, an ultrasonic disperser, or the like. The polymerizable monomer in which these various constituent materials are dissolved or dispersed is dispersed in oil droplets having a desired size as a toner in an aqueous medium containing a dispersion stabilizer using a homomixer or a homogenizer. Thereafter, the stirring mechanism is transferred to a reaction device (stirring device) which is a stirring blade described later, and the polymerization reaction is advanced by heating. After completion of the reaction, the dispersion stabilizer is removed, filtered, washed, and dried to prepare the toner of the present invention. In the present invention, the “aqueous medium” refers to a medium containing at least 50% by mass of water.
[0122]
Further, as a method for producing the toner of the present invention, a method in which resin particles are prepared by salting out, aggregating and fusing in an aqueous medium can also be mentioned. The method is not particularly limited, and examples thereof include methods disclosed in JP-A-5-265252, JP-A-6-329947, and JP-A-9-15904. That is, a method of salting out, agglomerating, and fusing a plurality of fine particles composed of resin particles and colorants, or a constituent material such as resin particles and a colorant, and in particular using an emulsifier in water Then, a coagulant with a critical coagulation concentration or higher is added for salting out, and at the same time, the formed polymer is heated and fused at a temperature higher than the glass transition temperature of the polymer itself to gradually grow the particle size while forming fused particles. When the desired particle size is reached, a large amount of water is added to stop particle size growth, and the shape is controlled by smoothing the particle surface while heating and stirring, and the particles are heated in a fluidized state while containing water. By drying, the toner of the present invention can be formed. Here, a solvent that is infinitely soluble in water, such as alcohol, may be added simultaneously with the flocculant.
[0123]
The toner manufacturing process mainly includes the following processes.
1: Multistage polymerization step (I) for obtaining composite resin particles in which a release agent is contained in a region other than the outermost layer (central portion or intermediate layer)
2: Salting out / fusion process for obtaining toner particles by salting out / fusion of composite resin particles and colorant particles (II)
3: Filtration / washing step of separating the toner particles from the toner particle dispersion and removing the surfactant from the toner particles.
4: a drying process for drying the washed toner particles;
5: Step of adding an external additive to the dried toner particles
Consists of
[0124]
Hereinafter, each step will be described in detail.
[Multistage polymerization step (I)]
The multistage polymerization step (I) is a step of producing composite resin particles by a multistage polymerization method in which a coating layer made of a monomer polymer is formed on the surface of the resin particles.
[0125]
In the present invention, it is preferable to employ a multi-stage polymerization method of three-stage polymerization or more from the viewpoint of production stability and crushing strength of the resulting toner.
[0126]
Hereinafter, the two-stage polymerization method and the three-stage polymerization method, which are representative examples of the multistage polymerization method, will be described.
[0127]
<Two-stage polymerization method>
The two-stage polymerization method is a method for producing composite resin particles composed of a central portion (core) formed from a high molecular weight resin containing a release agent and an outer layer (shell) formed from a low molecular weight resin. is there.
[0128]
This method will be described in detail. First, a release agent is dissolved in the monomer L to prepare a monomer solution, and this monomer solution is oiled in an aqueous medium (for example, a surfactant aqueous solution). After the dispersion, the system is polymerized (first stage polymerization) to prepare a dispersion of high molecular weight resin particles containing a release agent.
[0129]
Next, a polymerization initiator and a monomer L for obtaining a low molecular weight resin are added to the dispersion of the resin particles, and the monomer L is polymerized in the presence of the resin particles (second stage polymerization). This is a method of forming a coating layer made of a low molecular weight resin (polymer of monomer L) on the surface of the resin particles.
[0130]
<Three-stage polymerization method>
The three-stage polymerization method produces composite resin particles composed of a central part (core) formed from a high molecular weight resin, an intermediate layer containing a release agent, and an outer layer (shell) formed from a low molecular weight resin. Is the method.
[0131]
This method will be specifically described. First, a dispersion of resin particles obtained by a polymerization process (first-stage polymerization) according to a conventional method is added to an aqueous medium (for example, an aqueous solution of a surfactant). In the aqueous medium, a monomer solution obtained by dissolving a release agent in the monomer M is dispersed in oil droplets, and then this system is polymerized (second stage polymerization) to obtain resin particles ( Dispersion of composite resin particles (high molecular weight resin-intermediate molecular weight resin) by forming a coating layer (intermediate layer) made of a resin (monomer M polymer) containing a release agent on the surface of the core particles) Prepare the solution.
[0132]
Next, a polymerization initiator and a monomer L for obtaining a low molecular weight resin are added to the obtained dispersion of composite resin particles, and the monomer L is polymerized in the presence of the composite resin particles (third By step polymerization), a coating layer made of a low molecular weight resin (polymer of monomer L) is formed on the surface of the composite resin particles. In the above method, the incorporation of the second stage polymerization is preferable because the release agent can be finely and uniformly dispersed.
[0133]
The toner production method according to the present invention is characterized by polymerizing a polymerizable monomer in an aqueous medium. That is, when forming resin particles (core particles) or coating layer (intermediate layer) containing a release agent, the release agent is dissolved in the monomer, and the resulting monomer solution is oiled in an aqueous medium. In this method, latex particles are obtained by dispersing in drops and adding a polymerization initiator to this system to carry out polymerization treatment.
[0134]
The aqueous medium as used in the field of this invention means the medium which consists of 50-100 mass% of water and 0-50 mass% of water-soluble organic solvents. Examples of the water-soluble organic solvent include methanol, ethanol, isopropanol, butanol, acetone, methyl ethyl ketone, tetrahydrofuran, and the like, and an alcohol-based organic solvent that does not dissolve the obtained resin is preferable.
[0135]
As a suitable polymerization method for forming resin particles or a coating layer containing a release agent, a release agent is used as a monomer in an aqueous medium in which a surfactant having a concentration equal to or lower than the critical micelle concentration is dissolved. The monomer solution dissolved in is dispersed in oil droplets using mechanical energy to prepare a dispersion, and a water-soluble polymerization initiator is added to the resulting dispersion to cause radical polymerization in the oil droplets. A method (hereinafter referred to as “mini-emulsion method” in the present invention), and the effects of the present invention can be exhibited more preferably. In the above method, an oil-soluble polymerization initiator may be used instead of or together with the water-soluble polymerization initiator.
[0136]
According to the mini-emulsion method that mechanically forms oil droplets, unlike the usual emulsion polymerization method, the release agent dissolved in the oil phase is not detached, and the resin particles or the coating layer is formed. A sufficient amount of the release agent can be introduced.
[0137]
Here, the disperser for dispersing oil droplets by mechanical energy is not particularly limited. For example, the stirring device “CLEARMIX” (M technique (M Co., Ltd.), ultrasonic disperser, mechanical homogenizer, manton gorin, pressure homogenizer, and the like. The dispersed particle diameter is 10 to 1000 nm, preferably 50 to 1000 nm, and more preferably 30 to 300 nm.
[0138]
In addition, as another polymerization method for forming the resin particles or the coating layer containing the release agent, a known method such as an emulsion polymerization method, a suspension polymerization method, or a seed polymerization method may be employed. These polymerization methods can also be employed to obtain resin particles (core particles) or coating layers constituting the composite resin particles that do not contain a release agent.
[0139]
The particle diameter of the composite resin particles obtained in the polymerization step (I) is in the range of 10 to 1000 nm as a weight average particle diameter measured using an electrophoretic light scattering photometer “ELS-800” (manufactured by Otsuka Electronics Co., Ltd.). It is preferable that it exists in.
[0140]
Moreover, it is preferable that the glass transition temperature (Tg) of a composite resin particle exists in the range of 48-74 degreeC, More preferably, it is 52-64 degreeC.
[0141]
The softening point of the composite resin particles is preferably in the range of 95 to 140 ° C.
[Salting out / fusion process (II)]
In the salting out / fusion step (II), the composite resin particles and the colorant particles obtained in the multistage polymerization step (I) are salted out / fused (salting out and fusion occur simultaneously). This is a step of obtaining irregular (non-spherical) toner particles.
[0142]
In the present invention, salting out / fusion means that salting out (aggregation of particles) and fusion (disappearance of the interface between particles) occur simultaneously, or act of causing salting out and fusion at the same time. . In order to perform salting-out and fusion at the same time, it is necessary to agglomerate particles (composite resin particles, colorant particles) under a temperature condition higher than the glass transition temperature (Tg) of the resin constituting the composite resin particles. .
[0143]
In the salting-out / fusion step (II), internal additive particles such as charge control agents (fine particles having a number average primary particle size of about 10 to 1000 nm) are salted out / fused together with the composite resin particles and the colorant particles. You may let them. The colorant particles may be surface-modified, and conventionally known ones can be used as the surface modifier.
[0144]
The colorant particles are subjected to a salting out / fusion process in a state of being dispersed in an aqueous medium. The aqueous medium in which the colorant particles are dispersed is preferably an aqueous solution in which the surfactant is dissolved at a concentration equal to or higher than the critical micelle concentration (CMC).
[0145]
The disperser used for the dispersion treatment of the colorant particles is not particularly limited, but preferably a stirring device “CLEARMIX” (manufactured by M Technique Co., Ltd.) equipped with a rotor rotating at high speed, ultrasonic dispersion And pressure dispersers such as a mechanical homogenizer, manton gourin, and pressure homogenizer, and medium dispersers such as a Getzman mill and a diamond fine mill.
[0146]
In order to salt out / fuse the composite resin particles and the colorant particles, a salting-out agent (flocculating agent) having a critical aggregation concentration or more is added to the dispersion in which the composite resin particles and the colorant particles are dispersed. In addition, it is necessary to heat the dispersion to a temperature higher than the glass transition temperature (Tg) of the composite resin particles.
[0147]
The temperature range suitable for salting out / fusion is (Tg + 10) to (Tg + 50 ° C.), and particularly preferably (Tg + 15) to (Tg + 40 ° C.). In addition, an organic solvent that is infinitely soluble in water may be added in order to effectively perform fusion.
[0148]
[Filtering and washing process]
In this filtration / washing step, a filtration treatment for filtering the toner particles from the toner particle dispersion obtained in the above step, and a surfactant or salt from the filtered toner particles (cake-like aggregate). A cleaning process for removing deposits such as a depositing agent is performed.
[0149]
Here, the filtration method is not particularly limited, such as a centrifugal separation method, a vacuum filtration method using Nutsche or the like, a filtration method using a filter press or the like.
[0150]
[Drying process]
This step is a step of drying the washed toner particles.
[0151]
Examples of dryers used in this process include spray dryers, vacuum freeze dryers, vacuum dryers, etc., stationary shelf dryers, mobile shelf dryers, fluidized bed dryers, rotary dryers It is preferable to use a stirring dryer or the like.
[0152]
The water content of the dried toner particles is preferably 5% by mass or less, more preferably 2% by mass or less.
[0153]
Further, in producing the electrostatic image developing toner according to the present invention, particles are formed in an aqueous medium as described above, and after drying the particles, the fatty acid lithium salt according to the present invention is added in an amount of 0.005% by mass. Toner particles are produced by external addition in the range of ˜0.3% by mass.
[0154]
In addition, when the toner particles that have been dried are aggregated due to weak interparticle attraction, the aggregate may be crushed. Here, as the crushing treatment apparatus, a mechanical crushing apparatus such as a jet mill, a Henschel mixer, a coffee mill, or a food processor can be used.
[0155]
The toner of the present invention forms composite resin particles in the absence of a colorant, adds a dispersion of the colorant particles to the dispersion of the composite resin particles, and saltes out the composite resin particles and the colorant particles. It is preferably prepared by fusing.
[0156]
Thus, the polymerization reaction for obtaining the composite resin particles is not inhibited by preparing the composite resin particles in a system in which no colorant is present. Therefore, according to the toner of the present invention, the excellent offset resistance is not impaired, and the fixing device is not contaminated or the image is not stained due to the accumulation of toner.
[0157]
Further, as a result of the polymerization reaction for obtaining the composite resin particles being reliably performed, no monomer or oligomer remains in the obtained toner particles, and the heat fixing step of the image forming apparatus using the toner In this case, no off-flavor is generated.
[0158]
Furthermore, since the surface characteristics of the obtained toner particles are uniform and the charge amount distribution is sharp, an image with excellent sharpness can be formed over a long period of time. According to such a toner having a uniform composition, molecular weight, and surface characteristics between toner particles, an image forming apparatus including a fixing process using a contact heating method maintains good adhesion (high fixing strength) to an image support. However, it is possible to improve the anti-offset property and the anti-winding property, and an image having an appropriate gloss can be obtained.
[0159]
Next, each component used in the toner manufacturing process will be described in detail.
(Polymerizable monomer)
As a polymerizable monomer for producing the resin (binder) used in the present invention, a hydrophobic monomer is an essential constituent, and a crosslinkable monomer is used as necessary. Moreover, it is desirable to contain at least one monomer having an acidic polar group or a monomer having a basic polar group as described below.
[0160]
(1) Hydrophobic monomer
The hydrophobic monomer constituting the monomer component is not particularly limited, and conventionally known monomers can be used. Moreover, it can be used combining 1 type (s) or 2 or more types so that the required characteristic may be satisfy | filled.
[0161]
Specifically, monovinyl aromatic monomers, (meth) acrylic acid ester monomers, vinyl ester monomers, vinyl ether monomers, monoolefin monomers, diolefin monomers , Halogenated olefin monomers and the like can be used.
[0162]
Examples of vinyl aromatic monomers include styrene, o-methyl styrene, m-methyl styrene, p-methyl styrene, p-methoxy styrene, p-phenyl styrene, p-chloro styrene, p-ethyl styrene, p. -N-butyl styrene, p-tert-butyl styrene, pn-hexyl styrene, pn-octyl styrene, pn-nonyl styrene, pn-decyl styrene, pn-dodecyl styrene, 2, Examples thereof include styrene monomers such as 4-dimethylstyrene and 3,4-dichlorostyrene and derivatives thereof.
[0163]
Examples of acrylic monomers include acrylic acid, methacrylic acid, methyl acrylate, ethyl acrylate, butyl acrylate, 2-ethylhexyl acrylate, cyclohexyl acrylate, phenyl acrylate, methyl methacrylate, methyl methacrylate, methacrylic acid. Examples include butyl acid, hexyl methacrylate, 2-ethylhexyl methacrylate, ethyl β-hydroxyacrylate, propyl γ-aminoacrylate, stearyl methacrylate, dimethylaminoethyl methacrylate, diethylaminoethyl methacrylate, and the like.
[0164]
Examples of vinyl ester monomers include vinyl acetate, vinyl propionate, and vinyl benzoate.
[0165]
Examples of the vinyl ether monomer include vinyl methyl ether, vinyl ethyl ether, vinyl isobutyl ether, vinyl phenyl ether and the like.
[0166]
Examples of the monoolefin monomer include ethylene, propylene, isobutylene, 1-butene, 1-pentene, 4-methyl-1-pentene and the like.
[0167]
Examples of the diolefin monomer include butadiene, isoprene, chloroprene and the like.
[0168]
(2) Crosslinkable monomer
In order to improve the characteristics of the resin particles, a crosslinkable monomer may be added. Examples of the crosslinkable monomer include those having two or more unsaturated bonds such as divinylbenzene, divinylnaphthalene, divinyl ether, diethylene glycol methacrylate, ethylene glycol dimethacrylate, polyethylene glycol dimethacrylate, and diallyl phthalate.
[0169]
(3) Monomers having acidic polar groups
Examples of the monomer having an acidic polar group include (a) an α, β-ethylenically unsaturated compound having a carboxyl group (—COOH) and (b) a sulfone group (—SOOH)._ThreeMention may be made of α, β-ethylenically unsaturated compounds having H).
[0170]
Examples of the α, β-ethylenically unsaturated compound (a) having a —COO group include acrylic acid, methacrylic acid, fumaric acid, maleic acid, itaconic acid, cinnamic acid, maleic acid monobutyl ester, maleic acid. Examples thereof include acid monooctyl esters, and metal salts thereof such as Na and Zn.
[0171]
-SO of (b)_ThreeExamples of the α, β-ethylenically unsaturated compound having an H group include sulfonated styrene, its Na salt, allylsulfosuccinic acid, octyl allylsulfosuccinate, and its Na salt.
[0172]
(4) Monomers having basic polar groups
As the monomer having a basic polar group, (i) a (meth) acrylic acid ester of an aliphatic alcohol having 1 to 12, preferably 2 to 8, particularly preferably 2, an amine group or a quaternary ammonium group. , (Ii) (meth) acrylic acid amide or (meth) acrylic acid amide mono- or disubstituted optionally with an alkyl group having 1 to 18 carbon atoms on N, (iii) a heterocyclic group having N as a ring member And (iv) N, N-diallyl-alkylamine or a quaternary ammonium salt thereof. Among them, (i) aliphatic alcohol (meth) acrylic acid ester having an amine group or quaternary ammonium group is preferable as a monomer having a basic polar group.
[0173]
Examples of (meth) acrylic acid esters of aliphatic alcohols having an amine group or quaternary ammonium group (i) include dimethylaminoethyl acrylate, dimethylaminoethyl methacrylate, diethylaminoethyl acrylate, diethylaminoethyl methacrylate, and the above four compounds. A quaternary ammonium salt, 3-dimethylaminophenyl acrylate, 2-hydroxy-3-methacryloxypropyltrimethylammonium salt, etc. can be mentioned.
[0174]
(Ii) (Meth) acrylic acid amide or optionally mono- or dialkyl-substituted (meth) acrylic acid amide on N includes acrylamide, N-butylacrylamide, N, N-dibutylacrylamide, piperidylacrylamide, methacrylamide, N-butylmethacrylamide, N, N-dimethylacrylamide, N-octadecylacrylamide and the like can be mentioned.
[0175]
Examples of the vinyl compound substituted with a heterocyclic group having N as a ring member in (iii) include vinylpyridine, vinylpyrrolidone, vinyl-N-methylpyridinium chloride, vinyl-N-ethylpyridinium chloride and the like.
[0176]
Examples of (iv) N, N-diallyl-alkylamine include N, N-diallylmethylammonium chloride and N, N-diallylethylammonium chloride.
[0177]
(Polymerization initiator)
The radical polymerization initiator used in the present invention can be appropriately used as long as it is water-soluble. For example, persulfates (for example, potassium persulfate, ammonium persulfate, etc.), azo compounds (for example, 4,4′-azobis-4-cyanovaleric acid and its salts, 2,2′-azobis (2-amidinopropane) Salt), peroxide compounds and the like. Furthermore, the radical polymerization initiator can be combined with a reducing agent as required to form a redox initiator. Use of a redox initiator is preferable because the polymerization activity increases, the polymerization temperature can be lowered, and the polymerization time can be shortened.
[0178]
The polymerization temperature may be any temperature as long as it is equal to or higher than the minimum radical generation temperature of the polymerization initiator, but for example, a range of 50 ° C. to 90 ° C. is used. However, it is possible to perform polymerization at room temperature or higher by using a polymerization initiator that starts at room temperature, for example, a combination of hydrogen peroxide and a reducing agent (ascorbic acid or the like).
[0179]
(Chain transfer agent)
A known chain transfer agent can be used for the purpose of adjusting the molecular weight. Although it does not specifically limit as a chain transfer agent, For example, the compound which has mercapto groups, such as an octyl mercaptan, a dodecyl mercaptan, a tert- dodecyl mercaptan, is used. In particular, a compound having a mercapto group is preferably used because it suppresses odor during heat-fixing, and a toner having a sharp molecular weight distribution is obtained, and is excellent in storage stability, fixing strength, and offset resistance. For example, ethyl thioglycolate, propyl thioglycolate, propyl thioglycolate, butyl thioglycolate, t-butyl thioglycolate, 2-ethylhexyl thioglycolate, octyl thioglycolate, decyl thioglycolate, dodecyl thioglycolate , A compound having a mercapto group of ethylene glycol, a compound having a mercapto group of neopentyl glycol, and a compound having a mercapto group of pentaerythritol. Among these, n-octyl-3-mercaptopropionic acid ester is particularly preferable from the viewpoint of suppressing odor during toner heat fixing.
[0180]
(Surfactant)
In particular, in order to perform miniemulsion polymerization using the above-described polymerizable monomer, it is preferable to disperse oil droplets in an aqueous medium using a surfactant. The surfactant that can be used in this case is not particularly limited, and the following ionic surfactants can be given as examples of suitable compounds.
[0181]
Examples of the ionic surfactant include sulfonates (sodium dodecylbenzenesulfonate, sodium arylalkylpolyethersulfonate, 3,3-disulfonediphenylurea-4,4-diazo-bis-amino-8-naphthol- 6-sulfonate sodium, ortho-carboxybenzene-azo-dimethylaniline, 2,2,5,5-tetramethyl-triphenylmethane-4,4-diazo-bis-β-naphthol-6-sulfonate sodium, etc.) , Sulfate esters (sodium dodecyl sulfate, sodium tetradecyl sulfate, sodium pentadecyl sulfate, sodium octyl sulfate, etc.), fatty acid salts (sodium oleate, sodium laurate, sodium caprate, sodium caprylate, sodium caproate, steari Potassium, lithium oleate, and the like).
[0182]
Nonionic surfactants can also be used. Specifically, for example, polyethylene oxide, polypropylene oxide, a combination of polypropylene oxide and polyethylene oxide, ester of polyethylene glycol and higher fatty acid, alkylphenol polyethylene oxide, ester of higher fatty acid and polyethylene glycol, ester of higher fatty acid and polypropylene oxide, Examples include sorbitan esters.
[0183]
In the present invention, these surfactants are mainly used as an emulsifier during emulsion polymerization, but may be used for other steps or for other purposes.
[0184]
The resin particles used in the toner of the present invention and the molecular weight distribution of the toner of the present invention having the same as a constituent component will be described.
[0185]
The toner of the present invention preferably has a peak or shoulder at 100,000 to 1,000,000 and 1,000 to 50,000, and further has a peak or shoulder of 100,000 to 1,000,000, More preferably, it is present at 25,000 to 150,000 and 1,000 to 50,000.
[0186]
The molecular weight of the resin particles is both a high molecular weight component having a peak or shoulder in the region of 100,000 to 1,000,000 and a low molecular weight component having a peak or shoulder in the region of 1,000 to less than 50,000. A resin containing at least is preferable. More preferably, an intermediate molecular weight resin having a peak or shoulder at a peak molecular weight of 15,000 to 100,000 is preferably used.
[0187]
The molecular weight measurement method of the toner or resin is preferably measured by GPC (gel permeation chromatography) using THF (tetrahydrofuran) as a solvent. That is, 1.0 ml of THF is added to 0.5 to 5 mg of a measurement sample, more specifically 1 mg, and the mixture is sufficiently dissolved by stirring at room temperature using a magnetic stirrer or the like. Subsequently, after processing with a membrane filter having a pore size of 0.45 to 0.50 μm, the solution is injected into GPC. The measurement conditions of GPC are measured by stabilizing the column at 40 ° C., flowing THF at a flow rate of 1.0 ml / min, and injecting about 100 μl of a sample having a concentration of 1 mg / ml. The column is preferably used in combination with a commercially available polystyrene gel column. For example, combinations of Shodex GPC KF-801, 802, 803, 804, 805, 806, and 807 manufactured by Showa Denko KK and TSKgel G1000H, G2000H, G3000H, G4000H, G5000H, G6000H, G7000H, and TSKguard column manufactured by Tosoh Corporation And so on. As a detector, a refractive index detector (IR detector) or a UV detector may be used. In the measurement of the molecular weight of a sample, the molecular weight distribution of the sample is calculated using a calibration curve created using monodisperse polystyrene standard particles. About 10 points may be used as polystyrene for preparing a calibration curve.
[0188]
The aggregating agent used when producing the toner particles of the present invention will be described.
The flocculant used in the present invention is preferably selected from metal salts.
[0189]
Examples of the metal salt include monovalent metals such as alkali metal salts such as sodium, potassium and lithium, divalent metals such as alkaline earth metal salts such as lithium and magnesium, and divalent metals such as manganese and copper. Examples thereof include trivalent metal salts such as salts, iron and aluminum.
[0190]
Specific examples of these metal salts are shown below. Specific examples of monovalent metal salts include sodium chloride, potassium chloride, lithium chloride, and divalent metal salts such as lithium chloride, zinc chloride, copper sulfate, magnesium sulfate, and manganese sulfate. Examples of the trivalent metal salt include aluminum chloride and iron chloride. These are appropriately selected according to the purpose. In general, the divalent metal salt has a smaller critical aggregation concentration (coagulation value or coagulation point) than the monovalent metal salt, and the trivalent metal salt has a smaller critical aggregation concentration.
[0191]
The critical flocculation concentration referred to in the present invention is an index related to the stability of the dispersion in the aqueous dispersion, and indicates the concentration at which flocculation occurs when a flocculant is added. This critical coagulation concentration varies greatly depending on the latex itself and the dispersant. For example, it is described in Seizo Okamura et al., Polymer Chemistry 17,601 (1960), etc., and according to these descriptions, the value can be known. As another method, a desired salt is added to the target particle dispersion at a different concentration, the ζ potential of the dispersion is measured, and the salt concentration at the point where the ζ potential begins to change is defined as the critical aggregation concentration. It is also possible to do.
[0192]
In the present invention, the polymer fine particle dispersion is treated with a metal salt so as to have a concentration equal to or higher than the critical aggregation concentration. At this time, as a matter of course, whether the metal salt is added directly or as an aqueous solution is arbitrarily selected according to the purpose. When added as an aqueous solution, the added metal salt must be equal to or higher than the critical aggregation concentration of the polymer particles with respect to the volume of the polymer particle dispersion and the total volume of the metal salt aqueous solution.
[0193]
The concentration of the metal salt as a flocculant in the present invention may be not less than the critical aggregation concentration, but is preferably 1.2 times or more, more preferably 1.5 times or more the critical aggregation concentration.
[0194]
In the present invention, from the viewpoint of suppressing excessive charging of the toner particles and imparting uniform chargeability, the electrostatic charge image developing toner of the present invention is used to stabilize and maintain the chargeability, particularly to the environment. Preferably contains 250 to 20000 ppm, more preferably 800 to 5000 ppm, of the above-described metal elements (forms include metals, metal ions, etc.) in the toner.
[0195]
Moreover, in this invention, it is preferable that the total value of the bivalent (trivalent) metal element used for a coagulant | flocculant and the monovalent | monohydric metal element added as an aggregation terminator mentioned later is 350-35000 ppm.
[0196]
The residual amount of metal ions in the toner is measured using a fluorescent X-ray analyzer “System 3270 type” (manufactured by Rigaku Denki Kogyo Co., Ltd.), and the metal species of the metal salt used as the flocculant (for example, calcium chloride) It can be determined by measuring the intensity of the fluorescent X-ray emitted from the derived calcium or the like. As a specific measurement method, a plurality of toners having a known content ratio of the flocculant metal salt are prepared, each toner 5g is pelletized, the content ratio (mass ppm) of the flocculant metal salt, and the metal species of the metal salt The relationship (calibration curve) with the fluorescent X-ray intensity (peak intensity) is measured. Next, the toner (sample) whose content of the flocculant metal salt is to be measured is similarly pelletized, and the fluorescent X-ray intensity from the metal species of the flocculant metal salt is measured. Amount "can be obtained.
[0197]
The developer used in the present invention will be described.
The toner of the present invention may be used as a one-component developer or a two-component developer.
[0198]
When used as a one-component developer, a non-magnetic one-component developer or a magnetic one-component developer containing about 0.1 to 0.5 μm of magnetic particles in the toner can be used. be able to.
[0199]
Further, it can be mixed with a carrier and used as a two-component developer. In this case, conventionally known materials such as metals such as iron, ferrite and magnetite, and alloys of these metals with metals such as aluminum and lead can be used as the magnetic particles of the carrier. Ferrite particles are particularly preferable. The magnetic particles preferably have a volume average particle size of 15 to 100 μm, more preferably 25 to 80 μm.
[0200]
The volume average particle diameter of the carrier can be typically measured by a laser diffraction particle size distribution measuring apparatus “HELOS” (manufactured by SYMPATEC) equipped with a wet disperser.
[0201]
The carrier is preferably a carrier in which magnetic particles are further coated with a resin, or a so-called resin dispersion type carrier in which magnetic particles are dispersed in a resin. The resin composition for coating is not particularly limited, and for example, olefin resin, styrene resin, styrene-acrylic resin, silicone resin, ester resin, or fluorine-containing polymer resin is used. In addition, the resin for constituting the resin-dispersed carrier is not particularly limited, and a known resin can be used. For example, a styrene-acrylic resin, a polyester resin, a fluorine resin, a phenol resin, or the like is used. be able to.
[0202]
The image forming apparatus used in the present invention will be described.
The toner of the present invention is suitably used for an image forming apparatus including a step of fixing an image forming support on which a toner image is formed between a heating roller and a pressure roller constituting the fixing device. .
[0203]
FIG. 1 is a cross-sectional view showing an example of a fixing device using the toner of the present invention. The fixing device shown in FIG. 1 includes a heating roller 10 and a pressure roller 20 in contact with the heating roller 10. In FIG. 1, T is a toner image formed on a transfer paper (image forming support).
[0204]
The heating roller 10 has a coating layer 12 made of a fluororesin or an elastic body formed on the surface of the cored bar 11 and includes a heating member 13 made of a linear heater.
[0205]
The core metal 11 is made of metal and has an inner diameter of 10 to 70 mm. Although it does not specifically limit as a metal which comprises the metal core 11, For example, metals, such as iron, aluminum, copper, or these alloys can be mentioned.
[0206]
The thickness of the metal core 11 is set to 0.1 to 15 mm, and is determined in consideration of the balance between the request for energy saving (thinning) and the strength (depending on the constituent materials). For example, in order to maintain the same strength as that of a cored bar made of iron of 0.57 mm with a cored bar made of aluminum, the wall thickness needs to be 0.8 mm.
[0207]
Examples of the fluororesin constituting the coating layer 12 include PTFE (polytetrafluoroethylene) and PFA (tetrafluoroethylene-perfluoroalkyl vinyl ether copolymer).
[0208]
The thickness of the coating layer 12 made of a fluororesin is 10 to 500 μm, preferably 20 to 400 μm.
[0209]
When the thickness of the coating layer 12 made of a fluororesin is less than 10 μm, the function as the coating layer cannot be sufficiently exhibited, and the durability as the fixing device cannot be ensured. On the other hand, there is a problem that the surface of the coating layer exceeding 500 μm is easily scratched by paper dust, and toner or the like adheres to the scratched part, thereby causing image smearing. Further, as the elastic body constituting the coating layer 12, it is preferable to use silicone rubber, silicone sponge rubber, etc. having good heat resistance such as LTV, RTV, HTV.
[0210]
The Asker C hardness of the elastic body constituting the coating layer 12 is less than 80 °, preferably less than 60 °. Moreover, the thickness of the coating layer 12 made of an elastic body is 0.1 to 30 mm, preferably 0.1 to 20 mm.
[0211]
When the Asker C hardness of the elastic body constituting the coating layer 12 exceeds 80 ° and when the thickness of the coating layer 12 is less than 0.1 mm, the fixing nip cannot be increased, and soft fixing is performed. (For example, the effect of improving the color reproducibility by the toner layer at the smoothed interface) cannot be exhibited.
[0212]
As the heating member 13, a halogen heater can be suitably used.
The pressure roller 20 is formed by forming a coating layer 22 made of an elastic body on the surface of the core metal 21. The elastic body constituting the coating layer 22 is not particularly limited, and examples thereof include various soft rubbers such as urethane rubber and silicone rubber, and sponge rubber. The silicone rubber exemplified as the one constituting the coating layer 12 and It is preferable to use silicone sponge rubber.
[0213]
The Asker C hardness of the elastic body constituting the coating layer 22 is less than 80 °, preferably less than 70 °, and more preferably less than 60 °.
[0214]
The thickness of the coating layer 22 is 0.1 to 30 mm, preferably 0.1 to 20 mm.
[0215]
When the Asker C hardness of the elastic body constituting the coating layer 22 exceeds 80 ° and the thickness of the coating layer 22 is less than 0.1 mm, the fixing nip cannot be increased, and soft fixing is not possible. The effect cannot be demonstrated.
[0216]
Although it does not specifically limit as a material which comprises the core metal 21, Metals, such as aluminum, iron, copper, or those alloys can be mentioned.
[0217]
The contact load (total load) between the heating roller 10 and the pressure roller 20 is usually 40 to 350 N, preferably 50 to 300 N, and more preferably 50 to 250 N. This contact load is defined in consideration of the strength of the heating roller 10 (the thickness of the core metal 11). For example, in a heating roller having a core metal made of iron of 0.3 mm, the contact load should be 250 N or less. Is preferred.
[0218]
From the viewpoint of offset resistance and fixing property, the nip width is preferably 4 to 10 mm, and the surface pressure of the nip is 0.6 × 10 6.^FivePa ~ 1.5 × 10^FivePa is preferred.
[0219]
An example of fixing conditions by the fixing device shown in FIG. 1 is that the fixing temperature (surface temperature of the heating roller 10) is 150 to 210 ° C., and the fixing linear velocity is 80 to 640 mm / sec.
[0220]
The fixing device used in the present invention may be provided with a cleaning mechanism as necessary. In this case, as a method of supplying silicone oil to the upper roller (heating roller) of the fixing unit, a method of supplying and cleaning with a pad, roller, web or the like impregnated with silicone oil can be used.
[0221]
As the silicone oil, one having high heat resistance is used, and polydimethyl silicone, polyphenylmethyl silicone, polydiphenyl silicone and the like are used. Since a low-viscosity product has a large outflow during use, one having a viscosity at 20 ° C. of 1 to 100 Pa · s is preferably used.
[0222]
However, the effect of the present invention is particularly remarkable when the image forming process is included by a fixing device that does not supply silicone oil or that has a very low supply amount of silicone oil. Accordingly, even when silicone oil is supplied, the supply amount is preferably 2 mg or less per A4 sheet.
[0223]
By setting the amount of silicone oil to be 2 mg or less per A4 sheet, the amount of silicone oil attached to the transfer paper (image support) after fixing is reduced, and the oiliness of ballpoint pens and the like by the silicone oil attached to the transfer paper is reduced. There is no difficulty in writing the pen, and the writing property is not impaired.
[0224]
Further, it is possible to avoid problems such as a decrease in offset resistance over time due to silicone oil alteration and contamination of the optical system and band electrode due to silicone oil.
[0225]
Here, the amount of silicone oil supplied is such that 100 sheets of transfer paper (A4 size white paper) are continuously passed through the fixing device (between rollers) heated to a predetermined temperature, and the mass change (Δw ) Is calculated (Δw / 100).
[0226]
The cleaning blade used in the image forming apparatus according to the present invention will be described. The cleaning blade used in the present invention is preferably an elastic rubber blade, and its physical properties can control the torque fluctuation of the present invention by controlling the rubber hardness and the rebound resilience at the same time, and the reversal of the blade can be more effectively suppressed. When the JIS A hardness of the blade at 25 ± 5 ° C. is smaller than 65, the blade is easily reversed, and when it is larger than 80, the cleaning performance is deteriorated. Further, when the resilience exceeds 80, the blade is easily reversed, and when it is 20 or less, the cleaning performance is deteriorated. More preferable impact resilience is 20 or more and 80 or less. Young's modulus is 294-588 N / cm²The thing of the range of is preferable. (Both JISA hardness and impact resilience are measured based on the physical test method of vulcanized rubber of JIS K 6301. The value of impact resilience indicates%.)
As the material of the elastic rubber blade used for the cleaning blade, urethane rubber, silicon rubber, fluorine rubber, chloropyrene rubber, butadiene rubber, and the like are known, but among these, urethane rubber is compared with other rubbers. This is particularly preferable in terms of excellent wear characteristics. For example, urethane rubber obtained by reacting and curing polycaprolactone ester and polyisocyanate described in JP-A-59-30574 is preferable.
[0227]
In the present invention, it is preferable that the elastic rubber blade is fixed to the support member substantially by the support member on the photoreceptor contact surface side. By adopting such a holding method, the torque fluctuation of the cleaning blade can be stabilized.
[0228]
The proper pressure contact condition of the cleaning blade used in the image forming apparatus of the present invention will be described.
[0229]
The proper pressure contact condition of the elastic rubber blade to the surface of the photoreceptor is determined by a delicate balance of various characteristics and is quite narrow. The setting varies depending on characteristics such as the thickness of the elastic rubber blade, and requires precision. However, since elastic rubber blades can vary slightly in their thickness at the time of production, they cannot always be set under the proper conditions. May be out of the proper area. In particular, when combined with an organic photosensitive layer using a high molecular weight binder resin, image defects such as filming and black spots are likely to occur when the film deviates from an appropriate region.
[0230]
Therefore, it is necessary to take measures to cancel the variation in the characteristics of the elastic rubber blade. Even if the thickness of the elastic rubber blade is different, the pressure contact force on the surface of the photoreceptor is not affected. Would be effective.
[0231]
In the present invention, it is preferable that the free end of the elastic rubber blade is pressed in a direction opposite to the rotation direction of the photoreceptor (counter direction).
[0232]
If necessary, the cleaning blade can be sprayed with a fluorine-based lubricant on the edge of the cleaning blade, or further, the following fluorine-based polymer and fluorine-based resin powder can be applied to the tip of the cleaning blade over the entire width. It is preferable to apply a dispersion in which the body is dispersed in a fluorinated solvent.
[0233]
Next, the organic photoreceptor used in the image forming apparatus according to the present invention will be described.
In the present invention, an organic electrophotographic photoreceptor (organic photoreceptor) is an electrophotographic structure in which an organic compound has at least one of a charge generation function and a charge transport function essential to the construction of an electrophotographic photoreceptor. It means a photoreceptor, and all known organic electrophotographic photoreceptors such as a photoreceptor composed of a known organic charge generating material or an organic charge transport material, a photoreceptor composed of a polymer complex with a charge generating function and a charge transport function, etc. contains.
[0234]
The constitution of the organic photoreceptor used in the present invention is described below.
Conductive support
The conductive support used in the photoreceptor of the present invention may be either a sheet or a cylinder, but a cylindrical conductive support is more preferable for designing an image forming apparatus in a compact manner.
[0235]
The cylindrical conductive support of the present invention means a cylindrical support necessary for forming an endless image by rotating, and the straightness is in the range of 0.1 mm or less and the deflection is 0.1 mm or less. A conductive support is preferred. Exceeding the roundness and shake range makes it difficult to form a good image.
[0236]
As the conductive material, a metal drum such as aluminum or nickel, a plastic drum deposited with aluminum, tin oxide, indium oxide or the like, or a paper / plastic drum coated with a conductive substance can be used. As a conductive support, the specific resistance is 10 at room temperature.^ThreeΩcm or less is preferable.
[0237]
As the conductive support used in the present invention, one having an alumite film that has been sealed on the surface thereof may be used. The alumite treatment is usually performed in an acidic bath such as chromic acid, sulfuric acid, oxalic acid, phosphoric acid, boric acid, sulfamic acid, etc., but anodizing treatment in sulfuric acid gives the most preferable result. In the case of anodizing in sulfuric acid, the sulfuric acid concentration is preferably 100 to 200 g / l, the aluminum ion concentration is 1 to 10 g / l, the liquid temperature is about 20 ° C., and the applied voltage is preferably about 20 V. It is not limited. The average film thickness of the anodized film is usually 20 μm or less, particularly preferably 10 μm or less.
[0238]
Middle class
In the present invention, an intermediate layer having a barrier function may be provided between the conductive support and the photosensitive layer.
[0239]
In the present invention, in order to improve the adhesion between the conductive support and the photosensitive layer, or to prevent charge injection from the support, an intermediate layer (including an undercoat layer) is provided between the support and the photosensitive layer. Including) can also be provided. Examples of the material for the intermediate layer include polyamide resins, vinyl chloride resins, vinyl acetate resins, and copolymer resins containing two or more of these resin repeating units. Of these subbing resins, a polyamide resin is preferable as a resin capable of reducing the increase in residual potential due to repeated use. The film thickness of the intermediate layer using these resins is preferably 0.01 to 0.5 μm.
[0240]
The intermediate layer most preferably used in the present invention includes an intermediate layer using a curable metal resin obtained by thermally curing an organometallic compound such as a silane coupling agent or a titanium coupling agent. As for the film thickness of the intermediate | middle layer using curable metal resin, 0.1-2 micrometers is preferable.
[0241]
Photosensitive layer
The photosensitive layer configuration of the photoreceptor of the present invention may be a single layer photosensitive layer configuration in which a charge generation function and a charge transport function are provided on one layer on the intermediate layer. It is preferable that the generation layer (CGL) and the charge transport layer (CTL) be separated. By adopting a configuration in which the functions are separated, an increase in the residual potential due to repeated use can be controlled to be small, and other electrophotographic characteristics can be easily controlled according to the purpose. In the negatively charged photoconductor, it is preferable that a charge generation layer (CGL) is formed on the intermediate layer, and a charge transport layer (CTL) is formed thereon. In the positively charged photoconductor, the order of the layer configuration is the reverse of that in the negatively charged photoconductor. The most preferred photosensitive layer structure of the present invention is a negatively charged photoreceptor structure having the function separation structure.
[0242]
The structure of the photosensitive layer of the function-separated negatively charged photoreceptor will be described below.
Charge generation layer
Charge generation layer: The charge generation layer contains a charge generation material (CGM). Other substances may contain a binder resin and other additives as necessary.
[0243]
A known charge generation material (CGM) can be used as the charge generation material (CGM). For example, a phthalocyanine pigment, an azo pigment, a perylene pigment, an azulenium pigment, or the like can be used. Among these, the CGM that can minimize the increase in residual potential due to repeated use has a three-dimensional and potential structure that can form a stable aggregate structure among a plurality of molecules. Specifically, a phthalocyanine having a specific crystal structure. CGM of pigments and perylene pigments. For example, CGMs such as titanyl phthalocyanine having a maximum peak at a Bragg angle 2θ of 27.2 ° with respect to Cu—Kα rays and benzimidazole perylene having a maximum peak at 2θ of 12.4 have little deterioration due to repeated use. Potential increase can be reduced.
[0244]
When a binder is used as the CGM dispersion medium in the charge generation layer, a known resin can be used as the binder, but the most preferred resins include formal resin, butyral resin, silicone resin, silicone-modified butyral resin, phenoxy resin, and the like. Can be mentioned. The ratio of the binder resin to the charge generating material is preferably 20 to 600 parts by mass with respect to 100 parts by mass of the binder resin. By using these resins, the increase in residual potential associated with repeated use can be minimized. The thickness of the charge generation layer is preferably 0.01 μm to 2 μm.
[0245]
Charge transport layer
Charge transport layer: The charge transport layer contains a charge transport material (CTM) and a binder resin in which CTM is dispersed to form a film. Other substances may contain additives such as antioxidants as necessary.
[0246]
A known charge transport material (CTM) can be used as the charge transport material (CTM). For example, a triphenylamine derivative, a hydrazone compound, a styryl compound, a benzidine compound, a butadiene compound, or the like can be used. These charge transport materials are usually dissolved in a suitable binder resin to form a layer. Among these, the CTM capable of minimizing the increase in residual potential due to repeated use has a high mobility and an ionization potential difference from the combined CGM of 0.5 (eV) or less, preferably 0 .25 (eV) or less.
[0247]
The ionization potential of CGM and CTM is measured with a surface analyzer AC-1 (manufactured by Riken Keiki Co., Ltd.).
[0248]
Examples of the resin used for the charge transport layer (CTL) include polystyrene, acrylic resin, methacrylic resin, vinyl chloride resin, vinyl acetate resin, polyvinyl butyral resin, epoxy resin, polyurethane resin, phenol resin, polyester resin, alkyd resin, and polycarbonate. Resin, silicone resin, melamine resin, and copolymer resin containing two or more of repeating units of these resins. In addition to these insulating resins, high molecular organic semiconductors such as poly-N-vinylcarbazole can be used.
[0249]
Most preferred as a binder for these CTLs is a polycarbonate resin. The polycarbonate according to the present invention preferably has a viscosity average molecular weight of 40,000 or more, more preferably 50,000 or more. Specific examples of the polycarbonate according to the present invention include compound P described in JP-A-8-272125, pages 9 to 14.₁-1 to P₁-12, P₂-1 to P₂-10 and P_Three-1 to P_Three-10 etc. are mentioned. The polycarbonate resin is most preferable in improving the dispersibility and electrophotographic characteristics of CTM. The ratio of the binder resin to the charge transport material is preferably 10 to 200 parts by mass with respect to 100 parts by mass of the binder resin. The thickness of the charge transport layer is preferably 10 to 40 μm.
[0250]
Protective layer
Various resin layers can be provided as a protective layer of the photoreceptor. In particular, by providing a cross-linked resin layer, the organic photoreceptor of the present invention having high mechanical strength can be obtained.
[0251]
Examples of the solvent or dispersion medium used for forming the intermediate layer, photosensitive layer, protective layer and the like of the present invention include n-butylamine, diethylamine, ethylenediamine, isopropanolamine, triethanolamine, triethylenediamine, N, N-dimethylformamide, Acetone, methyl ethyl ketone, methyl isopropyl ketone, cyclohexanone, benzene, toluene, xylene, chloroform, dichloromethane, 1,2-dichloroethane, 1,2-dichloropropane, 1,1,2-trichloroethane, 1,1,1-trichloroethane, trichloroethylene , Tetrachloroethane, tetrahydrofuran, dioxolane, dioxane, methanol, ethanol, butanol, isopropanol, ethyl acetate, butyl acetate, dimethyl sulfoxide, methyl cello Lube, and the like. Although this invention is not limited to these, Dichloromethane, 1, 2- dichloroethane, methyl ethyl ketone, etc. are used preferably. These solvents may be used alone or as a mixed solvent of two or more.
[0252]
Next, as a coating processing method for producing the organic electrophotographic photoreceptor of the present invention, a coating processing method such as dip coating, spray coating, circular amount regulation type coating or the like is used. In order to prevent the lower layer film from being dissolved as much as possible, it is preferable to use a coating method such as spray coating or circular amount regulation type (circular slide hopper type is a typical example) coating in order to achieve uniform coating processing. It is most preferable that the protective layer of the present invention uses the circular amount regulation type coating method. The circular amount regulation type coating is described in detail in, for example, Japanese Patent Application Laid-Open No. 58-189061.
[0253]
【Example】
EXAMPLES Hereinafter, although an Example demonstrates this invention, this invention is not limited to these.
[0254]
Example 1
<Production of fatty acid lithium>
(Production of fatty acid lithium 1)
A reactor having the structure shown in FIG. 2, a reactor vessel 100 having a volume of 20 L, an upper stirring blade 600 having a length of 275 mm, and a lower stirring blade 700 having a length of 310 mm was prepared.
[0255]
In the reaction vessel of the reactor, A. V (204) 70% stearic acid-containing flakes (melting point 63 ° C.) 2750 g, lithium carbonate powder having an average particle size of 17 μm (manufactured by Nippon Chemical Industry Co., Ltd., trade name: lithium carbonate S) 377.6 g and water A raw material consisting of 1300 ml (47% of the amount of the flakes) was charged all at once, and the container was sealed. In addition, the temperature of the raw material at this time was 30 degreeC. The raw material is stirred and mixed at a speed of 16 m / sec (rotational speed of the longer stirring blade) by two agitating blades 600 and 700 which are rotatably attached to the rotating shaft by rotating the rotating shaft 400. The mixture was heated by passing warm water at 0 ° C. When the temperature in the reaction vessel 100 reaches about 40 ° C., carbon dioxide gas starts to be generated and the reaction starts, the pressure in the vessel rises, and the pressure gauge installed in the reaction vessel 100 becomes 0.0196 MPa (0 .2kg / cm²)showed that. In addition, water was generated by the reaction. Subsequently, when the heating and stirring were continued so as not to let carbon dioxide escape outside the reaction vessel 100, the temperature in the reaction vessel 100 increased and the pressure increased. In such a high-pressure atmosphere, the water in the reaction vessel 100 existed in a mist form. The maximum pressure during the reaction was 0.049 MPa (0.5 kg / cm²(The temperature in the reaction vessel 100 at this time was 60 ° C.).
[0256]
When the temperature in the reaction vessel 100 reached 75 ° C., the generation of carbon dioxide gas disappeared, the pressure decreased, and at the same time the contents solidified, and the reaction was terminated. It took 30 minutes from the start of the feed to the end of the reaction. Moreover, when the water content of the reaction product was measured, it was 15.0%.
[0257]
Thereafter, the warm water in the cavity 200 of the reaction vessel 100 was removed and switched to steam, and the temperature in the vessel 100 was set to 100 ° C. or higher. The fine powder of fatty acid lithium 1 having a 200 mesh pass of 99% or more (particle size of 74 μm or less) was produced by drying under reduced pressure for 30 minutes while continuing stirring with the two stirring blades described above.
[0258]
With respect to the obtained fatty acid lithium 1, when the amount of free fatty acid was measured by the method defined in JIS standards, it was 0.43% and the melting point was 217 ° C. Further, powder X-ray diffraction was performed, and the results are shown in FIG.
[0259]
(Production of fatty acid lithium 2-5)
In the production of the above-mentioned fatty acid lithium 1, the reaction time and the drying time under reduced pressure were changed, and the same procedure was carried out except that the fatty acid component, the amount of water (mass%) and the amount of free fatty acid (mass%) were prepared as shown in Table 1. Then, fatty acid lithium 2 to 5 were respectively produced.
[0260]
(Production of fatty acid lithium 6)
In the production of fatty acid lithium 1, as shown in Table 1, fatty acid lithium 6 was obtained in the same manner except that stearic acid and palmitic acid were used in a mass ratio of 399: 171 instead of stearic acid.
[0261]
Table 1 shows the properties of the obtained fatty acid lithium salt.
[0262]
[Table 1]

[0263]
<< Production of inorganic / organic composite fine particles used in the present invention >>
Styrene / acrylic organic fine particles with an average particle size of 1.0 μm (electric resistance 6.6 × 10¹³40 g of titanium oxide particle trade name ET-300W (manufactured by Ishihara Sangyo Co., Ltd.) whose surface has a primary particle diameter of 30 nm was treated with tin oxide was added to 100 g of Ω · cm), and mixed with a turbula mixer. Next, the hybridizer (manufactured by Nara Machinery Co., Ltd.) with a modified pulverizer was treated for 3 minutes at a peripheral speed of 100 m / sec to produce inorganic / organic composite fine particles in which titanium oxide was fixed on the surface of the organic fine particles. This is designated as “inorganic / organic composite fine particle 1”. The electric resistance of the inorganic / organic composite fine particle 1 is 4.8 × 10⁸It was Ω · cm.
[0264]
<Production example of resin particles for toner>
(Latex: Preparation of 1HML)
(1) Preparation of core particles (first stage polymerization):
Surfactant prepared by dissolving 7.08 g of an anionic surfactant (sodium dodecyl sulfonate: SDS) in 3010 g of ion-exchanged water in a 5000 ml separable flask equipped with a stirrer, temperature sensor, condenser, and nitrogen introducing device The solution (aqueous medium) was charged, and the internal temperature was raised to 80 ° C. while stirring at a stirring speed of 230 rpm under a nitrogen stream.
[0265]
To this surfactant solution, an initiator solution prepared by dissolving 9.2 g of a polymerization initiator (potassium persulfate: KPS) in 200 g of ion-exchanged water was added, the temperature was adjusted to 75 ° C., and then 70.1 g of styrene, n -A monomer mixture consisting of 19.9 g of butyl acrylate and 10.9 g of methacrylic acid was added dropwise over 1 hour, and this system was polymerized by heating and stirring at 75 ° C for 2 hours (first stage polymerization). And a latex (a dispersion of resin particles made of a high molecular weight resin) was prepared. This is referred to as “latex (1H)”.
[0266]
(2) Formation of intermediate layer (second stage polymerization):
In a flask equipped with a stirrer, 105.6 g of styrene, 30.0 g of n-butyl acrylate, 6.4 g of methacrylic acid, 5.6 g of n-octyl-3-mercaptopropionic acid ester, 72.0 g of the compound represented by the above 19) (hereinafter referred to as “Exemplary Compound (19)”) was added, heated to 80 ° C. and dissolved to prepare a monomer solution.
[0267]
On the other hand, a surfactant solution in which 1.6 g of an anionic surfactant (SDS) was dissolved in 2700 ml of ion-exchanged water was heated to 80 ° C., and the latex (dispersed core particle) was added to the surfactant solution. 1H) was added in an amount of 28 g in terms of solid content, and then the monomer solution of the exemplified compound (19) was prepared using a mechanical disperser “CLEARMIX” (manufactured by M Technique Co., Ltd.) having a circulation path. A dispersion (emulsion) containing emulsified particles (oil droplets) having a uniform dispersed particle diameter (284 nm) was prepared by mixing and dispersing.
[0268]
Next, an initiator solution prepared by dissolving 5.1 g of a polymerization initiator (KPS) in 240 ml of ion-exchanged water and 750 ml of ion-exchanged water were added to this dispersion (emulsion), and the system was heated at 80 ° C. Polymerization (second stage polymerization) was carried out by heating and stirring for 3 hours to obtain latex (a dispersion of composite resin particles having a structure in which the surface of resin particles made of high molecular weight resin was covered with intermediate molecular weight resin). This is referred to as “latex (1HM)”.
[0269]
(3) Formation of outer layer (third stage polymerization):
An initiator solution prepared by dissolving 7.4 g of a polymerization initiator (KPS) in 200 ml of ion-exchanged water is added to the latex (1HM) obtained as described above. A monomer mixed solution consisting of 95 g of n-butyl acrylate, 15.3 g of methacrylic acid, and 10.4 g of n-octyl-3-mercaptopropionic acid ester was added dropwise over 1 hour. After completion of the dropwise addition, polymerization (third stage polymerization) was performed by heating and stirring for 2 hours, followed by cooling to 28 ° C. and latex (a center portion made of a high molecular weight resin, an intermediate layer made of an intermediate molecular weight resin, A dispersion of composite resin particles) having an outer layer made of a molecular weight resin and containing the exemplified compound (19) in the intermediate layer was obtained. This latex is referred to as “latex (1HML)”.
[0270]
The composite resin particles constituting the latex (1HML) had peak molecular weights of 138,000, 80,000 and 13,000, and the number average particle diameter of the composite resin particles was 102 nm.
[0271]
(Preparation of latex 2HL)
(1) Preparation of core particles (first stage polymerization):
In a flask equipped with a stirrer, 72.0 g of Exemplified Compound (16) was added to a monomer mixture consisting of 105.6 g of styrene, 30.0 g of n-butyl acrylate, and 6.4 g of methacrylic acid, and 80 ° C. The monomer solution was prepared by heating and dissolving.
[0272]
On the other hand, a surfactant solution in which 1.6 g of an anionic surfactant (SDS) was dissolved in 2700 ml of ion-exchanged water was heated to 80 ° C., and a mechanical disperser “Claire having a circulation path was added to the surfactant solution. Mixing and dispersing the monomer solution of the exemplified compound (16) by “CLEARMIX” (manufactured by M Technique Co., Ltd.), including emulsified particles (oil droplets) having a uniform dispersed particle size (268 nm) A dispersion (emulsion) was prepared.
[0273]
Next, an initiator solution prepared by dissolving 5.1 g of a polymerization initiator (KPS) in 240 ml of ion-exchanged water and 750 ml of ion-exchanged water were added to this dispersion (emulsion), and the system was heated at 80 ° C. Polymerization (first stage polymerization) was performed by heating and stirring for 3 hours to prepare latex (a dispersion of resin particles made of a high molecular weight resin). This is referred to as “latex (2H)”.
[0274]
(2) Formation of outer layer (second stage polymerization):
An initiator solution obtained by dissolving 14.8 g of a polymerization initiator (KPS) in 400 ml of ion-exchanged water is added to the latex (2H) obtained as described above, and 600 g of styrene under a temperature condition of 80 ° C. A monomer mixed solution consisting of 190 g of n-butyl acrylate, 30.0 g of methacrylic acid, and 20.8 g of n-octyl-3-mercaptopropionic acid ester was added dropwise over 1 hour. After completion of the dropwise addition, polymerization (second stage polymerization) is performed by heating and stirring for 2 hours, followed by cooling to 28 ° C. and having a latex (a central portion made of a high molecular weight resin and an outer layer made of a low molecular weight resin). A dispersion of composite resin particles containing the exemplified compound (16) in the center was obtained. This latex is referred to as “latex (2HL)”.
[0275]
The composite resin particles constituting the latex (2HL) had peak molecular weights of 168,000 and 11,000, and the weight average particle size of the composite resin particles was 126 nm.
[0276]
<Production example of colored particles>
(Production of colored particles 1)
59.0 g of sodium n-dodecyl sulfate was dissolved in 1600 ml of ion-exchanged water with stirring. While stirring this solution, 420.0 g of carbon black “Regal 330” (manufactured by Cabot) was gradually added, and then dispersed using “Claremix” (manufactured by M Technique Co., Ltd.). A dispersion of colorant particles (hereinafter referred to as “colorant dispersion”) was prepared. When the particle diameter of the colorant particles in this colorant dispersion was measured using an electrophoretic light scattering photometer “ELS-800” (manufactured by Otsuka Electronics Co., Ltd.), the weight average particle diameter was 98 nm.
[0277]
Attach 420.7 g of latex (1HML) (converted to solid content), 900 g of ion-exchanged water, and 166 g of colorant dispersion, and attach a temperature sensor, cooling tube, nitrogen introducing device, stirring device, particle size and shape monitoring device The reaction vessel (reaction apparatus having the configuration shown in FIG. 4, crossing angle α is 25 °) (reaction apparatus having the configuration shown in FIG. 4, crossing angle α is 25 °) was stirred. After adjusting the internal temperature to 30 ° C., 5 mol / liter sodium hydroxide aqueous solution was added to this solution to adjust the pH to 11.0.
[0278]
Next, an aqueous solution in which 12.1 g of magnesium chloride hexahydrate was dissolved in 1000 ml of ion-exchanged water was added over 10 minutes at 30 ° C. with stirring. After standing for 3 minutes, the temperature increase was started, and the system was heated to 90 ± 3 ° C. over 6 to 10 minutes (temperature increase rate = 10 ° C./min). In this state, the particle size of the associated particles was measured with “Coulter Counter TA-II”, and when the volume average particle size became 5.5 μm, an aqueous solution in which 80.4 g of sodium chloride was dissolved in 1000 ml of ion-exchanged water. Was added to stop the particle growth, and the fusion was continued by heating and stirring at a liquid temperature of 85 ± 2 ° C. for 0.5 to 15 hours as an aging treatment.
[0279]
Then, it cooled to 30 degreeC on the conditions of 8 degreeC / min, hydrochloric acid was added, pH was adjusted to 2.0, and stirring was stopped. The produced associated particles are filtered using a Nutsche, washed repeatedly with ion-exchanged water, then dried at a suction air temperature of 60 ° C. using a flash jet dryer, and then at a temperature of 60 ° C. using a fluidized bed dryer. It was dried to obtain colored particles 1 containing a release agent [Exemplary Compound (19)] and having physical properties described in Table 2.
[0280]
(Production of colored particles 2 to 4)
In the production of the colored particles 1 described above, the coefficient of variation of the shape and shape factor is controlled by controlling the number of revolutions of stirring and the heating time in the monitoring of the salting-out / fusion step and the shape control step, and the particle size Similarly, colored particles 2 to 4 having the shape characteristics and the particle size distribution characteristics shown in Table 2 were obtained except that the coefficient of variation of the particle size distribution was arbitrarily adjusted.
[0281]
(Production of colored particles 5 to 8)
The shape shown in Table 2 in the same manner as in Colored Particle Production Examples 1 to 4, except that 420.7 g of latex (2HL) (solid content conversion) was used instead of latex (1HML) and the aging treatment time was changed. Colored particles 5 to 8 each having a characteristic and a particle size distribution characteristic were obtained. Table 2 shows the physical characteristics of the obtained colored particles.
[0282]
[Table 2]

[0283]
<Manufacture of toner particles>
Hydrophobic silica (number average primary particle size = 10 nm, hydrophobization degree = 63) is added to each of the colored particles 1 to 8 obtained as described above at a ratio of 1.0% by mass, and hydrophobic particles are added. Titanium oxide (number average primary particle size = 25 nm, hydrophobization degree = 60) was added at a ratio of 0.8% by mass and mixed with a Henschel mixer. Further, 0.1% by mass of the fatty acid lithium salt shown in Table 3 and 1% by mass of inorganic / organic composite fine particles or strontium titanate are added and mixed with a Henschel mixer, and the electrostatic image developing toner shown in Table 3 is added. Samples 1-15 were each produced.
[0284]
In preparation of the toner sample 1, a toner to which no fatty acid lithium salt was added was prepared as a comparative toner 1. In the preparation of the toner sample 1, a comparative toner 2 is obtained by using zinc stearate (Zinc stearate D manufactured by NOF Corporation) without using a fatty acid lithium salt.
[0285]
[Table 3]

[0286]
Here, the relationship between the physical characteristics of the electrostatic image developing toner particles and the colored particles according to the present invention will be described.
[0287]
In the production of the colored particles according to the present invention, the resin particles and the colorant are monitored during the salting-out / fusion step and the shape control step, and the shape and shape factor are controlled by reaction control such as the stirring speed and the heating time. The coefficient of variation of the particle size and the coefficient of variation of the particle size distribution are adjusted. An external additive is added to the colored particles thus obtained to produce toner particles. However, since the external additive is simply fixed to the surface of the toner particles, there is no physical change in the colored particles. The toner particles have the same physical characteristics (shape, particle size, etc.) as the colored particles.
[0288]
<Manufacture of carriers>
(Manufacture of ferrite core material)
22 mol% of MnO, Fe₂O_Three78 mol% was pulverized, mixed and dried in a wet ball mill for 2 hours, and then temporarily calcined by holding at 900 ° C. for 2 hours, and this was pulverized in a ball mill for 3 hours to form a slurry. A dispersant and a binder are added, granulated and dried by a spray dryer, then subjected to main firing at 1200 ° C. for 3 hours, an average grain diameter of 5.2 μm, and a resistance of 4.3 × 10.⁸Ω ferrite core material particles were obtained.
[0289]
(Manufacture of resin-coated carriers)
First, a cyclohexyl methacrylate / methyl methacrylate (copolymerization ratio 5 /) was prepared by emulsion polymerization using a sodium benzenesulfonate having an alkyl group having 12 carbon atoms as a surfactant in an aqueous medium at a concentration of 0.3% by mass. 5), a volume average primary particle size of 0.1 μm, a weight average molecular weight (Mw) of 200,000, a number average molecular weight (Mn) of 91,000, Mw / Mn = 2.2, and a softening point temperature. (Tsp) 230 ° C. and glass transition temperature (Tg) 110 ° C. Resin fine particles were obtained. The resin fine particles azeotroped with water in the emulsified state, and the residual monomer amount was 510 PPM.
[0290]
Next, 100 parts by mass of ferrite core material particles and 2 parts by mass of the resin fine particles are put into a high-speed agitator / mixer with agitating blades, and agitated and mixed at 120 ° C. for 30 minutes to use the action of mechanical impact force. Thus, a resin-coated carrier having a volume average particle size of 61 μm was obtained.
[0291]
<Manufacture of developer>
Toner samples 1 to 15 listed in Table 3 and comparative toner samples 1 and 2 were mixed with the carrier described above to prepare a developer having a toner concentration of 6 mass%. The obtained developers are referred to as developer samples 1 to 15 and comparative developers 1 and 2, respectively.
[0292]
<< Manufacture of photoconductor >>
30 g of polyamide resin Amilan CM-8000 (manufactured by Toray Industries, Inc.) was put into a mixed solvent of 900 ml of methanol and 100 ml of 1-butanol and dissolved by heating at 50 ° C. This liquid was applied onto a cylindrical aluminum conductive support having an outer diameter of 60 mm and a length of 360 mm to form an intermediate layer having a thickness of 0.5 μm.
[0293]
Next, 10 g of silicone resin KR-5240 (manufactured by Shin-Etsu Chemical Co., Ltd.) is dissolved in 1000 ml of t-butyl acetate, and 10 g of Y-TiOPc (described in JP-A No. 64-17066, FIG. 1) is mixed therein and a sand mill is used. For 20 hours to obtain a charge generation layer coating solution. Using this solution, the charge generation layer having a thickness of 0.3 μm was formed on the intermediate layer.
[0294]
Next, 150 g of CTM (T-1: N- (4-methylphenyl) -N- {4- (β-phenylstyryl) phenyl} -p-toluidine) and polycarbonate resin Iupilon Z-200 having a viscosity average molecular weight of 20,000. 200 g (Mitsubishi Gas Chemical Co., Ltd.) was dissolved in 1000 ml of 1,2-dichloroethane to obtain a charge transport layer coating solution. Using this solution, the charge generation layer was coated with a circular slide hopper, and then dried at 100 ° C. for 1 hour to form a 22 μm thick charge transport layer. Thus, a photoreceptor (P1) comprising an intermediate layer, a charge generation layer, and a charge transport layer was obtained. Next, on the surface of the photoreceptor sample (P1), 30 g of CTM (T-1) and 50 g of polycarbonate resin Iupilon Z-800 (Mitsubishi Gas Chemical Co., Ltd.) having a viscosity average molecular weight of 80,000 were added to 1000 ml of 1,2-dichloroethane. Using the dissolved coating solution, coating was performed on the charge transport layer with a circular slide hopper, followed by drying at 100 ° C. for 1 hour to form a 5 μm thick overcoat layer. Obtained.
[0295]
An image having a pixel rate of 15% in a high-temperature and high-humidity environment (temperature 33 ° C., relative humidity 80%) using a modified machine in which the obtained photoreceptor (P2) is mounted on a commercially available digital copying machine Konica Sitos 7030. A live-action test was carried out to form 300,000 sheets continuously, and the blade wear amount, toner particle slip-through, image blur, and the environmental dependency of image density were evaluated.
[0296]
《Blade wear amount》
After printing 100,000 sheets, the cleaning blade was removed from the cleaning device, and the portion that disappeared due to wear was measured with a laser microscope. If the amount of wear is within 20 μm, the level is satisfactory (practical).
[0297]
<Slip through toner particles>
Evaluation was made based on the number of toners detected (visually evaluated) as image smudges from the cleaning device on the photoreceptor on the white background of the image.
[0298]
Image blur
A character image having a character size of 5 points was formed on the entire surface of the image, and the number of images until the image was locally blurred or a portion where toner oozes around the image was detected was visually evaluated. More than 200,000 sheets can be used.
[0299]
<Environmental dependence of image density>
The maximum image density of the solid image portion was measured with a Macbeth reflection densitometer. The difference in image density between the high temperature and high humidity environment (33 ° C., 80% RH) and the low temperature and low humidity environment (10 ° C., 20% RH) is less than 0.05, and “0.05” is 0.05 to 0.1. And those exceeding 0.1 were evaluated as “x”.
[0300]
Table 4 shows the obtained results.
[0301]
[Table 4]

[0302]
From Table 4, it is clear that the sample of the present invention has less abrasion of the cleaning blade and slipping out of the toner particles as compared with the comparison, and the image blur and the image dependency of the environment are good.
[0303]
【The invention's effect】
According to the present invention, there is no slip of toner particles from the cleaning device during image formation, the amount of wear of the cleaning blade of the cleaning device is reduced, there is no image blur, and the image density of the formed image is dependent on the environment. The toner for developing an electrostatic charge image, a method for producing the same, and an image forming apparatus can be provided.
[Brief description of the drawings]
FIG. 1 is a schematic cross-sectional view showing an example of a fixing device (fixing device) used in the present invention.
FIG. 2 is a cross-sectional view showing an example of an apparatus used for producing a fatty acid lithium salt according to the present invention.
FIG. 3 is a characteristic diagram showing a powder X-ray diffraction pattern of a fine powder of lithium stearate prepared in Example 1 of the present invention.
FIG. 4 is a perspective view of an example of a stirring tank provided with stirring blades.
FIG. 5 is a schematic diagram illustrating toner particles having no corners.
[Explanation of symbols]
1 jacket
2 Mixing tank
3 Rotating shaft
4, 5 stirring blade
9 Baffle plate
α Crossing angle between stirring blades
8 Image carrier
10 Heating roll
11 Core of heating roll
12 Heating roll coating layer
13 Heating member
20 Pressure roll
21 Core of pressure roll
22 Covering layer of pressure roll
T Toner image
100 containers
200 cavity
300 holes
400 rotation axis
500 bearings
600, 700 stirring blade
800 lids

Claims (16)

In the toner for developing electrostatic images having toner particles obtained by polymerizing a polymerizable monomer in an aqueous medium, the toner may have a fatty acid lithium salt as the at least one external additive, the fatty acid lithium The amount of water in the salt is 0.1% by weight to 1.4% by weight, the amount of free fatty acid in the fatty acid lithium salt is 0.01% by weight to 0.7% by weight, and the toner particles are resin particles. A toner for developing an electrostatic charge image, which is produced through a process of aggregation and fusion in an aqueous medium . The electrostatic image developing toner according to claim 1, wherein the fatty acid lithium salt is lithium stearate. The toner particles have, as external additives, inorganic / organic composite fine particles in which inorganic fine particles having a primary average particle size of 5 nm to 100 nm are fixed on the surface of organic fine particles having an average particle size of 0.1 μm to 5.0 μm. The toner for developing an electrostatic charge image according to claim 1, wherein: The number average particle diameter of the toner particles is 2 μm to 8 μm, the variation coefficient of the shape factor is 16% or less, and the number variation coefficient in the number particle size distribution is 27% or less. 2. The toner for developing an electrostatic charge image according to item 1. The number average particle diameter of the toner particles is 2 μm to 8 μm, and the ratio of the toner particles having a shape factor in the range of 1.0 to 1.6 is 65% by number or more. Item 4. The toner for developing an electrostatic charge image according to any one of Items 1 to 3. The number average particle diameter of the toner particles is 2 μm to 8 μm, and the ratio of the toner particles having a shape factor in the range of 1.2 to 1.6 is 65% by number or more. Item 4. The toner for developing an electrostatic charge image according to any one of Items 1 to 3. The number average particle diameter of the toner particles is 2 μm to 8 μm, and the ratio of the toner particles having no corners to all the toner particles is 50% by number or more. Toner for developing electrostatic images. When the particle size of toner particles is D (μm), the natural logarithm lnD is taken on the horizontal axis, and the horizontal axis is divided into a plurality of classes at intervals of 0.23 to the most frequent class in the histogram showing the number-based particle size distribution. The sum (M) of the relative frequency (m1) of the toner particles contained and the relative frequency (m2) of the toner particles contained in the next most frequent class is 70% or more. The toner for developing an electrostatic charge image according to any one of claims 1 to 7. The ratio of toner particles having no corners to all toner particles is 50% by number or more, and the number variation coefficient in the number particle size distribution is 27% or less. Toner for developing electrostatic images. 2. A ratio of toner particles having a shape factor in a range of 1.2 to 1.6 to all toner particles is 65% by number or more, and a variation coefficient of the shape factor is 16% or less. The toner for developing an electrostatic charge image according to any one of 1 to 9. 11. The toner particles according to claim 1, wherein the toner particles are produced through a step of salting out, aggregating, and fusing the composite resin particles obtained by a multistage polymerization method and the colorant particles. The toner for developing an electrostatic image according to the description. The GPC (gel permeation chromatography) measurement of the toner has peaks or shoulders present at least in the range of 100,000 to 1,000,000 and 1,000 to 50,000. 2. The toner for developing an electrostatic charge image according to item 1. In the GPC (gel permeation chromatography) measurement of the toner, the peak or shoulder is present in at least 100,000 to 1,000,000, 25,000 to 100,000, and 1,000 to 25,000. The toner for developing an electrostatic charge image according to any one of claims 1 to 11. An electrostatic image formed on an organic photoreceptor is developed with a developer having the electrostatic image developing toner according to any one of claims 1 to 13, and a toner image visualized by the development. Is transferred from the organophotoreceptor to a transfer material, and the toner remaining on the organophotoreceptor is transferred. An image forming apparatus having a cleaning device for removing the toner. 15. The image forming apparatus according to claim 14, wherein the organic photoreceptor has a photosensitive layer on a conductive support, and the surface layer of the photosensitive layer contains polycarbonate having an average molecular weight of 40,000 or more. In producing the toner for developing an electrostatic charge image according to any one of claims 1 to 13, particles are formed in an aqueous medium, and after the particles are dried, the fatty acid lithium salt is added in an amount of 0.005% by mass to 0%. A method for producing a toner for developing an electrostatic charge image, wherein toner particles are produced by external addition in the range of 3% by mass.

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