JP2005049396A - Nonmagnetic toner and image forming method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a toner which exhibits stable electrostatic properties independently of the environment and can give high quality images nearly free of image degradation such as fog over a prolonged period of time. <P>SOLUTION: The nonmagnetic toner comprises at least a binder resin, a colorant, a charge control agent and a polymer having sulfur atoms, wherein the charge control agent is a metal compound of an aromatic oxycarboxylic acid, in which the metal comprises a metal selected from the group consisting of aluminum, zinc, chromium, cobalt, nickel, zirconium, titanium, copper and iron. A mass A (mg/g) of the oxycarboxylic acid extracted from 1g of the toner by an aqueous solution of 0.1 mol/l sodium hydroxide is A=0.10-3.00 mg/g (based on the mass of the toner), the ratio (S/C) of number% of atoms of elementary sulfur (S) to number% of atoms of elementary carbon (C) present in a toner surface measured by X-ray photoelectron spectroscopic analysis is 0.0003-0.0050, an average circularity of the toner is 0.955-0.995 and a standard deviation of circularity is <0.035. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

【００５５】
特定中心金属を有するオキシカルボン酸は、重合性単量体１００質量部当り０．１〜２質量部含有することが好ましい。より好ましくは０．２〜１．５質量部、更に好ましくは０．３〜１．２質量部含有することが最適である。
【００５６】
上記錯体化合物の添加量が０．１質量部未満であると、トナー表面における錯体存在量が少なく、初期時から帯電能力が劣る。一方、２質量部より多いと、トナー表面存在量が過多な為、特に高温高湿環境における耐久後のカブリ特性が悪い。
【００５７】
本発明を懸濁重合法により合成してトナーを得る場合、硫黄原子を有する樹脂の添加量は、結着樹脂１００質量部に対して０．１〜２質量部含有することが好ましい。より好ましい範囲は０．２〜１．５質量部である。
【００５８】
硫黄原子を有する樹脂添加量が０．１質量部未満の場合、帯電サイトであるスルホン酸基のトナー表面存在量が乏しく、帯電分布を安定化させる効果が得られない。
【００５９】
一方、２質量部を超えると、造粒工程における液滴安定性が悪化し、平均円径度や粒度分布が乱れる。
【００６０】
また、本発明のトナーは、硫黄原子を有する重合体（ａ）と、該芳香族オキシカルボン酸の金属化合物（ｂ）の含有比率がａ：ｂ＝９０：１０〜１０：９０、より好ましくは８０：２０〜２０：８０の範囲であり、該トナーの個数分布における変動係数が４０以下、より好ましくは３５以下であることにより、ロングライフでカブリの発生が抑えられ、多数枚のプリントを経た後でも良好なハーフトーン再現性が達成させる。
【００６１】
上記含有比率が９０：１０〜１０：９０を満たさない場合、各々の荷電制御機能のバランスが崩れ、長期耐久における帯電制御能力に劣る。
【００６２】
変動係数が４０より大きくなると、長期耐久時に現像機内の粒度分布が変動することによってトナー個々の帯電量にばらつきが発生し、カブリラチチュードが狭くなり耐久性能に劣る。
【００６３】
尚、トナー中の硫黄原子を有する樹脂の含有量は、キャピラリー電気泳動法などを用いて測定することができる。
【００６４】
また、個数分布における変動係数は、下記式により求めることができ、後に示す方法で、コールターカウンターＴＡ−ＩＩ型あるいはコールターマルチサイザー（コールター社製）等で測定できる。
【００６５】
【数１】

【００６６】
本発明における硫黄原子を有する樹脂とは、後述するゲルパーミエーションクロマトグラフィーのポリスチレン換算分子量において１０００以上の範囲にピークトップを有し、かつ前記の範囲に溶出される成分中に硫黄元素が含有されているものを示す。硫黄元素の価数や結合状態は、Ｘ線光電子分光分析により測定されるトナー表面に存在する結合エネルギー１６６〜１７２ｅＶにピークトップを有していることが好ましい。その中でも、４価または６価が好ましく、６価がより好ましい。また、結合状態は、スルホン、スルホン酸、スルホン酸塩、硫酸エステル、硫酸エステル塩などが好ましく、スルホン酸、スルホン酸塩、硫酸エステル、硫酸エステル塩がより好ましい。
【００６７】
本発明の硫黄原子を有する樹脂は、本発明に用いられる硫黄原子を有する樹脂を製造するための含硫黄単量体としては、スチレンスルホン酸、２−アクリルアミド−２−メチルプロパンスルホン酸、２−メタクリルアミド−２−メチルプロパンスルホン酸、ビニルスルホン酸、メタクリルスルホン酸等或いは、下記構造を有するマレイン酸アミド誘導体、マレイミド誘導体、スチレン誘導体がある。
【００６８】
【化２】

（結合部位は、オルト位或いはパラ位である。）
【００６９】
本発明に係る硫黄原子を有する樹脂は、上記単量体の単重合体であっても構わないが、上記単量体と他の単量体との共重合体であっても構わない。上記単量体と共重合体をなす単量体としては、ビニル系重合性単量体があり、単官能性重合性単量体或いは多官能性重合性単量体を使用することが出来る。
【００７０】
本発明のトナーの円形度、所望の平均粒径を得る上では、上記単量体のうちスルホン酸を有する共重合体が好ましく、スルホン酸基含有（メタ）アクリルアミドがより好ましい。
【００７１】
単官能性重合性単量体としては、スチレン；α−メチルスチレン、β−メチルスチレン、ｏ−メチルスチレン、ｍ−メチルスチレン、ｐ−メチルスチレン、２，４−ジメチルスチレン、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、ｐ−メトキシスチレン、ｐ−フェニルスチレンの如きスチレン誘導体；メチルアクリレート、エチルアクリレート、ｎ−プロピルアクリレート、ｉｓｏ−プロピルアクリレート、ｎ−ブチルアクリレート、ｉｓｏ−ブチルアクリレート、ｔｅｒｔ−ブチルアクリレート、ｎ−アミルアクリレート、ｎ−ヘキシルアクリレート、２−エチルヘキシルアクリレート、ｎ−オクチルアクリレート、ｎ−ノニルアクリレート、シクロヘキシルアクリレート、ベンジルアクリレート、ジメチルフォスフェートエチルアクリレート、ジエチルフォスフェートエチルアクリレート、ジブチルフォスフェートエチルアクリレート、２−ベンゾイルオキシエチルアクリレートの如きアクリル系重合性単量体；メチルメタクリレート、エチルメタクリレート、ｎ−プロピルメタクリレート、ｉｓｏ−プロピルメタクリレート、ｎ−ブチルメタクリレート、ｉｓｏ−ブチルメタクリレート、ｔｅｒｔ−ブチルメタクリレート、ｎ−アミルメタクリレート、ｎ−ヘキシルメタクリレート、２−エチルヘキシルメタクリレート、ｎ−オクチルメタクリレート、ｎ−ノニルメタクリレート、ジエチルフォスフェートエチルメタクリレート、ジブチルフォスフェートエチルメタクリレートの如きメタクリル系重合性単量体；メチレン脂肪族モノカルボン酸エステル；酢酸ビニル、プロピオン酸ビニル、酪酸ビニル、安息香酸ビニル、ギ酸ビニルの如きビニルエステル；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の如きビニルエーテル；ビニルメチルケトン、ビニルヘキシルケトン、ビニルイソプロピルケトンの如きビニルケトンが挙げられる。
【００７２】
多官能性重合性単量体としては、ジエチレングリコールジアクリレート、トリエチレングリコールジアクリレート、テトラエチレングリコールジアクリレート、ポリエチレングリコールジアクリレート、１，６−ヘキサンジオールジアクリレート、ネオペンチルグリコールジアクリレート、トリプロピレングリコールジアクリレート、ポリプロピレングリコールジアクリレート、２，２’−ビス（４−（アクリロキシ・ジエトキシ）フェニル）プロパン、トリメチロールプロパントリアクリレート、テトラメチロールメタンテトラアクリレート、エチレングリコールジメタクリレート、ジエチレングリコールジメタクリレート、トリエチレングリコールジメタクリレート、テトラ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、１，３−ブチレングリコールジメタクリレート、１，６−ヘキサンジオールジメタクリレート、ネオペンチルグリコールジメタクリレート、ポリプロピレングリコールジメタクリレート、２，２’−ビス（４−（メタクリロキシ・ジエトキシ）フェニル）プロパン、２，２’−ビス（４−メタクリロキシ・ポリエトキシ）フェニル）プロパン、トリメチロールプロパントリメタクリレート、テトラメチロールメタンテトラメタクリレート、ジビニルベンゼン、ジビニルナフタリン、ジビニルエーテル等が挙げられる。
【００７３】
硫黄原子を有する樹脂としては、上述の如き単量体を用いることができるが、スチレン誘導体を単量体として含有していることが、より好ましい。
【００７４】
硫黄原子を有する樹脂の製造方法は、塊状重合、溶液重合、乳化重合、懸濁重合、イオン重合等があるが、操作性などの面から溶液重合が好ましい。
【００７５】
硫黄原子を有する樹脂のうち該スルホン酸基を有する重合体を構成する単量体としては、
Ｘ（ＳＯ_３ ⁻）ｎ・ｍＹ^ｋ＋
（Ｘ：前記重合性単量体に由来する重合体部位を表し、Ｙ^＋：カウンターイオンを表し、ｋはカウンターイオンの価数であり、ｍ及びｎは整数であり、ｎ＝ｋ×ｍである。）
の如き構造を有する。カウンターイオンとしては、水素イオン、ナトリウムイオン、カリウムイオン、カルシウムイオン、アンモニウムイオンなどであることが好ましい。
【００７６】
硫黄原子を有する樹脂において、スルホン酸基を有する重合体の酸価（ｍｇＫＯＨ／ｇ）は３乃至５０が好ましい。より好ましくは５乃至４０が良い。
【００７７】
酸価が３未満の場合には、本発明で言及するような十分な荷電制御作用が得られず、かつ環境特性が悪い。酸価が５０を超える場合には、この様な重合体を含有する組成物を用いて、懸濁重合で粒子を造る場合、トナー粒子がいびつな形状を有する様になり、円形度が小さくなってしまい、含有する離型剤がトナー表面に現れ、現像性の低下をひきおこす。
【００７８】
硫黄原子を有する樹脂の分子量は重量平均分子量（Ｍｗ）が２０００乃至１０００００が好ましい。重量平均分子量（Ｍｗ）が２０００未満の場合には、トナーの流動性が悪くなり、転写性が悪化する。１０００００を超える場合には、単量体への溶解に時間がかかることに加え、顔料の分散性も悪くなり、トナーの着色力が低下してしまう。
【００７９】
硫黄原子を有する樹脂のガラス転移点（Ｔｇ）は５０℃乃至１００℃が好ましい。ガラス転移点が５０℃未満の場合には、トナーの流動性、保存性に劣り、さらに転写性も劣るようになる。ガラス転移点が１００℃を超える場合には、トナー印字率の多い画像の時の定着性に劣る。
【００８０】
硫黄原子を有する樹脂の揮発分は０．０１％乃至２．０％が好ましい。揮発分を０．０１％未満とするためには、揮発分除去工程が複雑になり、揮発分が２．０％を超える場合には、高温高湿下での帯電、特に放置後の帯電に関して劣る様になる。該重合体揮発分は、高温（１３５℃）で１時間加熱したときに減少する重量の割合である。
【００８１】
なお、硫黄原子を有する樹脂のトナーからの抽出は特に制限されるものではなく、任意の方法が扱える。
【００８２】
以下、本発明のトナーの必須条件である、平均円形度及び円形度標準偏差について説明する。
【００８３】
本発明のトナーは、平均円形度が、０．９５５以上０．９９５以下であることが必須である。平均円形度が０．９５５以上のトナーは、表面のエッジ部が少ないため、一つの粒子内での電荷の局在化が起こりにくく、帯電量分布もシャープになる傾向にあり、潜像に対して忠実に現像される。
【００８４】
一方、平均円形度が０．９９５を超えるトナーは、円形度が非常に高く、クリーニング不良が懸念される為に好ましくない。
【００８５】
更に、本発明のトナーは、トナー粒子の円形度頻度分布の円形度標準偏差を０．０３５未満、好ましくは０．０３０未満とすることにより、トナー担持体上にトナーの薄層を形成する際に、トナー帯電量を適切なものとすることが可能となり、均一な薄層コート性が達成される。
【００８６】
円形度標準偏差が０．０３５以上の場合、帯電分布が広がる傾向があり、カブリ等のラティチュードが狭くなる。
【００８７】
本発明における平均円形度は、粒子の形状を定量的に表現する簡便な方法として用いたものであり、本発明では東亜医用電子製フロー式粒子像分析装置「ＦＰＩＡ−１０００」を用いて測定を行い、３μｍ以上の円相当径の粒子群について測定された各粒子の円径度（ａｉ）を下式（１）によりそれぞれもとめ、さらに下式（２）で示すように測定された全粒子の円形度の総和を、全粒子数（ｍ）で除した値を平均円形度（ａ）と定義する。
【００８８】
【数２】

【００８９】
【数３】

【００９０】
なお、本発明で用いている測定装置である「ＦＰＩＡ−１０００」は、各粒子の円形度を算出後、平均円形度の算出に当たって、粒子を得られた円形度によって、円形度０．４０〜１．００を６１分割したクラスに分け、分割点の中心値と頻度を用いて平均円形度の算出を行う算出法を用いている。しかしながら、この算出式で算出される平均円形度の各値との誤差は、非常に少なく、実質的に無視出来る程度のものであり、本発明においては、算出時間の短縮化や算出演算式の簡略化の如きデータの取り扱い上の理由で、上述した各粒子の円形度を直接用いる算出式の概念を利用し、一部変更したこのような算出式を用いても良い。
【００９１】
測定手段としては以下の通りである。界面活性剤を約０．１ｍｇ溶解している水１０ｍｌに現像剤５ｍｇを分散させて分散液を調製し、超音波（２０ＫＨｚ、５０Ｗ）を分散液に５分間照射し、分散液濃度を５０００〜２万個／μｌとして前記装置により測定を行い、３μｍ以上の円相当径の粒子群の平均円形度を求める。
【００９２】
本発明における平均円形度とは、現像剤の凹凸の度合いの指標であり、現像剤が完全な球形の場合１．０００を示し、表面形状が複雑になるほど円形度は小さな値となる。
【００９３】
なお、本測定において３μｍ以上の円相当径の粒子群についてのみ円形度を測定する理由は、３μｍ未満の円相当径の粒子群にはトナー粒子とは独立して存在する外部添加剤の粒子群も多数含まれるため、その影響によりトナー粒子群についての円形度が正確に見積もれないからである。
【００９４】
次に、トナーの粒径について説明する。
【００９５】
本発明のトナーは、更に高画質化のため、より微小な潜像ドットを忠実に現像するためには、本発明のトナーの重量平均径は３μｍ〜１０μｍであることが好ましい。このトナーの重量平均径は、４μｍ〜８μｍであることが更に好ましい。重量平均径が３μｍ未満のトナーにおいては、粉体としての流動性及び攪拌性が低下し、個々のトナー粒子を均一に帯電させることが困難となることからカブリや転写性が悪化傾向となり、画像の不均一ムラの原因となりやすいため、本発明で使用するトナーには好ましくない。また、トナーの重量平均径が１０μｍを越える場合には、文字やライン画像に飛び散りが生じやすく、高解像度が得られにくい。さらに装置が高解像度になっていくと８μｍ以上のトナーは１ドットの再現が悪化する傾向にある。
【００９６】
本発明のトナーの重量平均粒径及び数平均粒径はコールターカウンターＴＡ−ＩＩ型あるいはコールターマルチサイザー（コールター社製）等種々の方法で測定可能である。具体的には、下記のように測定できる。コールターマルチサイザー（コールター社製）を用い、個数分布、体積分布を出力するインターフェイス（日科機製）及びＰＣ９８０１パーソナルコンピューター（ＮＥＣ製）を接続し、電解液は１級塩化ナトリウムを用いて１％ＮａＣｌ水溶液を調整する。たとえば、ＩＳＯＴＯＮ Ｒ−ＩＩ（コールターサイエンティフィックジャパン社製）が使用できる。測定手順は以下の通りである。前記電解水溶液を１００〜１５０ｍｌ加え、更に測定試料を２〜２０ｍｇ加える。試料を懸濁した電解液は超音波分散器で約１〜３分間分散処理を行い前記コールターマルチサイザーによりアパーチャーを用いて、２μｍ以上のトナー粒子の体積、個数を測定して体積分布と個数分布とを算出する。それから、本発明に係わる所の体積分布から求めた体積基準の重量平均粒径（Ｄ４）及び個数分布から求めた個数基準の平均粒径、すなわち個数平均粒径（Ｄ１）を求める。
【００９７】
本発明のトナー粒子は重合法によって得られる粒子であるのが好ましい。本発明に係わるトナーは、粉砕法によって製造することも可能であるが、この粉砕法で得られるトナー粒子は一般に不定形のものであり、本発明の好ましい要件である平均円形度が０．９５５〜０．９９５という物性を得るためには機械的・熱的あるいは何らかの特殊な処理を行うことが必要となる。
【００９８】
そこで、上述の諸問題を解決するため、本発明においては、トナー粒子を重合法により製造することが好ましい。トナーの重合法としては、直接重合法、懸濁重合法、乳化重合法、乳化会合重合法、シード重合法等が挙げられるが、これらの中では、粒径と粒子形状のバランスのとりやすさという点で、特に懸濁重合法により製造することが好ましい。この懸濁重合法においては重合性単量体および着色剤（更に必要に応じて重合開始剤、架橋剤、荷電制御剤、その他の添加剤）を均一に溶解または分散せしめて単量体組成物とした後、この単量体組成物を分散安定剤を含有する連続層（例えば水相）中に適当な撹拌器を用いて分散し同時に重合反応を行わせ、所望の粒径を有するトナーを得るものである。この懸濁重合法で得られるトナー（以後重合トナー）は、個々のトナー粒子形状がほぼ球形に揃っているため、平均円形度が０．９５５〜０．９９５以上という物性要件を満たすトナーが得られやすく、さらにこういったトナーは帯電量の分布も比較的均一となるため高い転写性を有している。
【００９９】
さらに、懸濁重合して得られた微粒子に再度、重合性単量体と重合開始剤を添加して表面層を設けるコア・シェル構造も必要に応じて設計することが可能である。
【０１００】
本発明のトナーは、結着樹脂１００質量部に対して０．５〜５０重量部の離型剤を含有することも好ましい。結着樹脂としては、後述するように例えば、各種のワックス等が例示できる。
【０１０１】
転写材上に転写されたトナー像はその後、熱・圧力等のエネルギーにより転写材上に定着され、半永久的画像が得られる。この際、熱ロール式定着やフィルム式定着が一般に良く用いられる。
【０１０２】
前述のように、重量平均粒径が１０μｍ以下のトナー粒子を用いれば非常に高精細な画像を得ることができるが、粒径の細かいトナー粒子は紙等の転写材を使用した場合に紙の繊維の隙間に入り込み、熱定着用ローラーからの熱の受け取りが不十分となり、低温オフセットが発生しやすい。しかしながら、本発明に係わるトナーにおいて、適正量の離型剤を含有させることにより、高解像性と耐オフセット性を両立させつつることが可能となる。
【０１０３】
本発明に係わるトナーに使用可能な離型剤としては、パラフィンワックス、マイクロクリスタリンワックス、ペトロラクタム等の石油系ワックス及びその誘導体、モンタンワックスびその誘導体、フィッシャートロプシュ法による炭化水素ワックス及びその誘導体、ポリエチレンに代表されるポリオレフィンワックス及びその誘導体、カルナバワックス、キャンデリラワックス等天然ワックス及びその誘導体などである。これらの誘導体には酸化物や、ビニル系モノマーとのブロック共重合物、グラフト変性物を含む。さらには、高級脂肪族アルコール、ステアリン酸、パルミチン酸等の脂肪酸、あるいはその化合物、酸アミドワックス、エステルワックス、ケトン、硬化ヒマシ油及びその誘導体、植物系ワックス、動物性ワックス等が挙げられる。これらのワックスの中では、示差熱分析における吸熱ピークが４０℃〜１１０℃であるものが好ましく、更には４５℃〜９０℃であるものが好ましい。
【０１０４】
離型剤を使用する際の含有量としては、結着樹脂１００質量部に対して０．５〜５０質量部の範囲が好ましい。含有量が０．５質量部未満では低温オフセット抑制効果に乏しく、５０質量部を超えてしまうと長期間の保存性が悪化すると共に、他のトナー材料の分散性が悪くなり、トナーの流動性の悪化や画像特性の低下につながる。
【０１０５】
ワックス成分の最大吸熱ピーク温度の測定は、「ＡＳＴＭ Ｄ ３４１８−８」に準じて行う。測定には、例えばパーキンエルマー社製ＤＳＣ−７を用いる。装置検出部の温度補正はインジウムと亜鉛の融点を用い、熱量の補正についてはインジウムの融解熱を用いる。測定サンプルにはアルミニウム製のパンを用い、対照用に空パンをセットし、昇温速度１０℃／ｍｉｎで測定を行う。
【０１０６】
また、硫黄原子を有する樹脂のガラス転移温度（Ｔｇ）は、２度目の昇温時のＤＳＣカーブより、吸熱ピーク前の基線と吸熱ピーク後の基線の中線と、立ち上がり曲線での交点をもってしてＴｇとした。
【０１０７】
本発明のトナーには、着色力を付与するために着色剤を必須成分として含有する。本発明に好ましく使用される有機顔料または染料として以下のものが挙げられる。
【０１０８】
シアン系着色剤としての有機顔料又は有機染料としては、銅フタロシアニン化合物及びその誘導体，アントラキノン化合物，塩基染料レーキ化合物等が利用できる。具体的には、Ｃ．Ｉ．ピグメントブルー１，Ｃ．Ｉ．ピグメントブルー７，Ｃ．Ｉ．ピグメントブルー１５，Ｃ．Ｉ．ピグメントブルー１５：１，Ｃ．Ｉ．ピグメントブルー１５：２，Ｃ．Ｉ．ピグメントブルー１５：３，Ｃ．Ｉ．ピグメントブルー１５：４，Ｃ．Ｉ．ピグメントブルー６０，Ｃ．Ｉ．ピグメントブルー６２，Ｃ．Ｉ．ピグメントブルー６６等が挙げられる。
【０１０９】
マゼンタ系着色剤としての有機顔料又は有機染料としては、縮合アゾ化合物，ジケトピロロピロール化合物，アントラキノン，キナクリドン化合物，塩基染料レーキ化合物，ナフトール化合物，ベンズイミダゾロン化合物，チオインジゴ化合物，ペリレン化合物が用いられる。具体的には、Ｃ．Ｉ．ピグメントレッド２，Ｃ．Ｉ．ピグメントレッド３，Ｃ．Ｉ．ピグメントレッド５，Ｃ．Ｉ．ピグメントレッド６，Ｃ．Ｉ．ピグメントレッド７，Ｃ．Ｉ．ピグメントバイオレット１９，Ｃ．Ｉ．ピグメントレッド２３，Ｃ．Ｉ．ピグメントレッド４８：２，Ｃ．Ｉ．ピグメントレッド４８：３，Ｃ．Ｉ．ピグメントレッド４８：４，Ｃ．Ｉ．ピグメントレッド５７：１，Ｃ．Ｉ．ピグメントレッド８１：１，Ｃ．Ｉ．ピグメントレッド１２２，Ｃ．Ｉ．ピグメントレッド１４４，Ｃ．Ｉ．ピグメントレッド１４６，Ｃ．Ｉ．ピグメントレッド１５０，Ｃ．Ｉ．ピグメントレッド１６６，Ｃ．Ｉ．ピグメントレッド１６９，Ｃ．Ｉ．ピグメントレッド１７７，Ｃ．Ｉ．ピグメントレッド１８４，Ｃ．Ｉ．ピグメントレッド１８５，Ｃ．Ｉ．ピグメントレッド２０２，Ｃ．Ｉ．ピグメントレッド２０６，Ｃ．Ｉ．ピグメントレッド２２０，Ｃ．Ｉ．ピグメントレッド２２１，Ｃ．Ｉ．ピグメントレッド２５４等が挙げられる。
【０１１０】
イエロー系着色剤としての有機顔料又は有機染料としては、縮合アゾ化合物，イソインドリノン化合物，アントラキノン化合物，アゾ金属錯体，メチン化合物，アリルアミド化合物に代表される化合物が用いられる。具体的には、Ｃ．Ｉ．ピグメントイエロー１２，Ｃ．Ｉ．ピグメントイエロー１３，Ｃ．Ｉ．ピグメントイエロー１４，Ｃ．Ｉ．ピグメントイエロー１５，Ｃ．Ｉ．ピグメントイエロー１７，Ｃ．Ｉ．ピグメントイエロー６２，Ｃ．Ｉ．ピグメントイエロー７４，Ｃ．Ｉ．ピグメントイエロー８３，Ｃ．Ｉ．ピグメントイエロー９３，Ｃ．Ｉ．ピグメントイエロー９４，Ｃ．Ｉ．ピグメントイエロー９５，Ｃ．Ｉ．ピグメントイエロー９７，Ｃ．Ｉ．ピグメントイエロー１０９，Ｃ．Ｉ．ピグメントイエロー１１０，Ｃ．Ｉ．ピグメントイエロー１１１，Ｃ．Ｉ．ピグメントイエロー１２０，Ｃ．Ｉ．ピグメントイエロー１２７，Ｃ．Ｉ．ピグメントイエロー１２８，Ｃ．Ｉ．ピグメントイエロー１２９，Ｃ．Ｉ．ピグメントイエロー１４７，Ｃ．Ｉ．ピグメントイエロー１５１，Ｃ．Ｉ．ピグメントイエロー１５４，Ｃ．Ｉ．ピグメントイエロー１６８，Ｃ．Ｉ．ピグメントイエロー１７４，Ｃ．Ｉ．ピグメントイエロー１７５，Ｃ．Ｉ．ピグメントイエロー１７６，Ｃ．Ｉ．ピグメントイエロー１８０，Ｃ．Ｉ．ピグメントイエロー１８１，Ｃ．Ｉ．ピグメントイエロー１９１，Ｃ．Ｉ．ピグメントイエロー１９４等が挙げられる。
【０１１１】
これらの着色剤は、単独又は混合しさらには固溶体の状態で用いることができる。本発明のトナーに用いられる着色剤は、色相角，彩度，明度，耐光性，ＯＨＰ透明性，トナーへの分散性の点から選択される。
【０１１２】
該着色剤の添加量は、結着樹脂１００質量部に対し１〜２０質量部添加して用いられる。
【０１１３】
黒色着色剤としては、カーボンブラック、磁性体、上記イエロー／マゼンタ／シアン着色剤を用い黒色に調色されたものが利用される。
【０１１４】
本発明においては重合法を用いてトナーを得る場合には、着色剤の持つ重合阻害性や水相移行性に注意を払う必要があり、好ましくは、表面改質、例えば、重合阻害のない物質による疎水化処理を施しておいたほうが良い。特に、染料系やカーボンブラックは、重合阻害性を有しているものが多いので使用の際に注意を要する。染料系を表面処理する好ましい方法としては、あらかじめこれら染料の存在下に重合性単量体を重合せしめる方法が挙げられ、得られた着色重合体を単量体系に添加する。
【０１１５】
また、カーボンブラックについては、上記染料と同様の処理の他、カーボンブラックの表面官能基と反応する物質、例えば、ポリオルガノシロキサン等で処理を行っても良い。
【０１１６】
本発明のトナーには、荷電特性を安定化するために、第三成分となる荷電制御剤を配合しても良い。荷電制御剤としては、公知のものが利用でき、特に帯電スピードが速く、かつ、一定の帯電量を安定して維持できる荷電制御剤が好ましい。さらに、トナーを直接重合法を用いて製造する場合には、重合阻害性が低く、水系分散媒体への可溶化物が実質的にない荷電制御剤が特に好ましい。しかしながら、本発明のトナーには、更なる荷電制御剤の添加は必須ではなく、トナーの層厚規制部材やトナー担持体との摩擦帯電を積極的に利用することでトナー中に必ずしも第三荷電制御剤を含む必要はない。
【０１１７】
次に本発明のトナーの懸濁重合法による製造方法を説明する。
【０１１８】
本発明のトナーを懸濁重合法で製造する場合、使用される重合性単量体系を構成する重合性単量体としては以下のものが挙げられる。
【０１１９】
重合性単量体としては、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−エチルスチレン等のスチレン系単量体、アクリル酸メチル・アクリル酸エチル・アクリル酸ｎ−ブチル・アクリル酸イソブチル・アクリル酸ｎ−プロピル・アクリル酸ｎ−オクチル・アクリル酸ドデシル・アクリル酸２−エチルヘキシル・アクリル酸ステアリル・アクリル酸２−クロルエチル・アクリル酸フェニル等のアクリル酸エステル類、メタクリル酸メチル・メタクリル酸エチル・メタクリル酸ｎ−プロピル・メタクリル酸ｎ−ブチル・メタクリル酸イソブチル・メタクリル酸ｎ−オクチル・メタクリル酸ドデシル・メタクリル酸２−エチルヘキシル・メタクリル酸ステアリル・メタクリル酸フェニル・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のメタクリル酸エステル類その他のアクリロニトリル・メタクリロニトリル・アクリルアミド等の単量体が挙げられる。
【０１２０】
これらの単量体は単独、または混合して使用し得る。上述の単量体の中でも、スチレンまたはスチレン誘導体を単独で、あるいはほかの単量体と混合して使用することがトナーの現像特性及び耐久性の点から好ましい。
【０１２１】
本発明に係わる重合トナーの製造においては、単量体系に樹脂を添加して重合しても良い。
【０１２２】
例えば、単量体では水溶性のため水性懸濁液中では溶解して乳化重合を起こすため使用できないアミノ基、カルボン酸基、水酸基、グリシジル基、ニトリル基等、親水性官能基含有の単量体成分をトナー中に導入したい時には、これらとスチレンあるいはエチレン等ビニル化合物とのランダム共重合体、ブロック共重合体あるいはグラフト共重合体等、共重合体の形にして、あるいはポリエステル、ポリアミド等の重縮合体、ポリエーテル、ポリイミン等重付加重合体の形で使用が可能となる。こうした極性官能基を含む高分子重合体をトナー中に共存させると、前述のワックス成分を相分離させ、より内包化が強力となり、耐オフセット性、耐ブロッキング性、低温定着性の良好なトナーを得ることができる。
【０１２３】
また、材料の分散性や定着性、あるいは画像特性の改良等を目的として上記以外の樹脂を単量体系中に添加しても良く、用いられる樹脂としては、例えば、ポリスチレン、ポリビニルトルエンなどのスチレン及びその置換体の単重合体；スチレン−プロピレン共重合体、スチレン−ビニルトルエン共重合体、スチレン−ビニルナフタリン共重合体、スチレン−アクリル酸メチル共重合体、スチレン−アクリル酸エチル共重合体、スチレン−アクリル酸ブチル共重合体、スチレン−アクリル酸オクチル共重合体、スチレン−アクリル酸ジメチルアミノエチル共重合体、スチレン−メタクリル酸メチル共重合体、スチレン−メタクリル酸エチル共重合体、スチレン−メタクリル酸ブチル共重合体、スチレン−メタクリル酸ジメチルアミノエチル共重合体、スチレン−ビニルメチルエーテル共重合体、スチレン−ビニルエチルエーテル共重合体、スチレン−ビニルメチルケトン共重合体、スチレン−ブタジエン共重合体、スチレン−イソプレン共重合体、スチレン−マレイン酸共重合体、スチレン−マレイン酸エステル共重合体などのスチレン系共重合体；ポリメチルメタクリレート、ポリブチルメタクリレート、ポリ酢酸ビニル、ポリエチレン、ポリプロピレン、ポリビニルブチラール、シリコーン樹脂、ポリエステル樹脂、ポリアミド樹脂、エポキシ樹脂、ポリアクリル酸樹脂、ロジン、変性ロジン、テルペン樹脂、フェノール樹脂、脂肪族または脂環族炭化水素樹脂、芳香族系石油樹脂などが単独或いは混合して使用できる。
【０１２４】
これら樹脂の添加量としては、単量体１００質量部に対し１〜２０質量部が好ましい。１質量部未満では添加効果が小さく、一方２０質量部を超えると重合トナーの種々の物性設計が難しくなる。
【０１２５】
さらに、単量体を重合して得られるトナーの分子量範囲とは異なる分子量の重合体を単量体中に溶解して重合すれば、分子量分布の広い、耐オフセット性の高いトナーを得ることができる。
【０１２６】
本発明に係わる重合トナーの製造において使用される重合開始剤としては、重合反応時に半減期０．５〜３０時間であるものを、重合性単量体１００質量部に対し０．５〜２０質量部の添加量で重合反応を行うと、分子量１万〜１０万の間に極大を有する重合体を得、トナーに望ましい強度と適当な溶融特性を与えることができる。重合開始剤例としては、２，２’−アゾビス−（２，４−ジメチルバレロニトリル）、２，２’−アゾビスイソブチロニトリル、１，１’−アゾビス（シクロヘキサン−１−カルボニトリル）、２，２’−アゾビス−４−メトキシ−２，４−ジメチルバレロニトリル、アゾビスイソブチロニトリル等のアゾ系またはジアゾ系重合開始剤；ベンゾイルパーオキサイド、ｔ−ブチルパーオキシ２−エチルヘキサノエート、ｔ−ブチルパーオキシピバレート、ｔ−ブチルパーオキシイソブチレート、ｔ−ブチルパーオキシネオデカノエート、メチルエチルケトンパーオキサイド、ジイソプロピルパーオキシカーボネート、クメンヒドロパーオキサイド、２，４−ジクロロベンゾイルパーオキサイド、ラウロイルパーオキサイド等の過酸化物系重合開始剤が挙げられる。
【０１２７】
本発明に係わる重合トナーを製造する際は、架橋剤を添加しても良く、好ましい添加量としては、０．００１〜１５質量％である。
【０１２８】
本発明に関わる重合トナーを製造する際は、分子量調整剤を使用することができる。分子量調整剤としては、例えば、ｔ−ドデシルメルカプタン、ｎ−ドデシルメルカプタン、ｎ−オクチルメルカプタンなどのメルカプタン類；四塩化炭素、四臭化炭素などのハロゲン化炭化水素類；α−メチルスチレンダイマーなどを挙げることができる。これらの分子量調整剤は、重合開始前あるいは重合途中に添加することができる。分子量調整剤は、重合性単量体１００質量部に対して、通常、０．０１〜１０質量部、好ましくは０．１〜５質量部の割合で用いられる。
【０１２９】
本発明に関わる重合トナーの製造方法では、一般に上述のトナー組成物、すなわち重合性単量体中に、スルホン酸基を有する重合体、離型剤、可塑剤、荷電制御剤、架橋剤、場合によって着色剤等トナーとして必要な成分及びその他の添加剤、例えば重合反応で生成する重合体の粘度を低下させるために入れる有機溶媒、高分子重合体、分散剤等を適宜加えて、ホモジナイザー、ボールミル、コロイドミル、超音波分散機等の分散機によって均一に溶解または分散せしめた単量体系を、分散安定剤を含有する水系媒体中に懸濁する。この時、高速撹拌機もしくは超音波分散機のような高速分散機を使用して一気に所望のトナー粒子のサイズとするほうが、得られるトナー粒子の粒径がシャープになる。重合開始剤添加の時期としては、重合性単量体中に他の添加剤を添加する時同時に加えても良いし、水系媒体中に懸濁する直前に混合しても良い。また、造粒直後、重合反応を開始する前に重合性単量体あるいは溶媒に溶解した重合開始剤を加えることもできる。
【０１３０】
造粒後は、通常の撹拌機を用いて、粒子状態が維持され且つ粒子の浮遊・沈降が防止される程度の撹拌を行えば良い。
【０１３１】
本発明に係わる重合トナーを製造する場合には、分散安定剤として公知の界面活性剤や有機あるいは無機分散剤が使用でき、中でも無機分散剤が有害な超微粉を生じ難く、その立体障害性により分散安定性を得ているので反応温度を変化させても安定性が崩れ難く、洗浄も容易でトナーに悪影響を与え難いので、好ましく使用できる。こうした無機分散剤の例としては、燐酸カルシウム、燐酸マグネシウム、燐酸アルミニウム、燐酸亜鉛等の燐酸多価金属塩、炭酸カルシウム、炭酸マグネシウム等の炭酸塩、メタ硅酸カルシウム、硫酸カルシウム、硫酸バリウム等の無機塩、水酸化カルシウム、水酸化マグネシウム、水酸化アルミニウム、シリカ、ベントナイト、アルミナ等の無機酸化物が挙げられる。
【０１３２】
これらの無機分散剤は、重合性単量体１００質量部に対して０．２〜２０質量部を単独で使用しても良く、粒度分布を調整する目的で０．００１〜０．１質量部の界面活性剤を併用しても良い。界面活性剤としては、例えばドデシルベンゼン硫酸ナトリウム、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、オレイン酸ナトリウム、ラウリル酸ナトリウム、ステアリン酸ナトリウム、ステアリン酸カリウム等が挙げられる。
【０１３３】
これら無機分散剤を用いる場合には、そのまま使用しても良いが、より細かい粒子を得るため、水系媒体中にて該無機分散剤粒子を生成させることができる。例えば、燐酸カルシウムの場合、高速撹拌下、燐酸ナトリウム水溶液と塩化カルシウム水溶液とを混合して、水不溶性の燐酸カルシウムを生成させることができ、より均一で細かな分散が可能となる。この時、同時に水溶性の塩化ナトリウム塩が副生するが、水系媒体中に水溶性塩が存在すると、重合性単量体の水への溶解が抑制されて、乳化重合による超微粒トナーが発生し難くなるので、より好都合である。重合反応終期に残存重合性単量体を除去する時には障害となることから、水系媒体を交換するか、イオン交換樹脂で脱塩したほうが良い。無機分散剤は、重合終了後酸あるいはアルカリで溶解して、ほぼ完全に取り除くことができる。
【０１３４】
前記重合工程においては、重合温度は４０℃以上、一般には５０〜９０℃の温度に設定して重合を行う。この温度範囲で重合を行うと、内部に封じられるべき離型剤やワックスの類が、相分離により析出して内包化がより完全となる。残存する重合性単量体を消費するために、重合反応終期ならば、反応温度を９０〜１５０℃にまで上げることは可能である。重合トナー粒子は重合終了後、公知の方法によって濾過、洗浄、乾燥を行い、無機微粉体を混合し表面に付着させることで、トナーを得ることができる。また、製造工程に分級工程を入れ、粗粉や微粉をカットすることも、望ましい形態の一つである。
【０１３５】
本発明のトナーを粉砕法により製造する場合は、公知の方法が用いられるが、例えば、結着樹脂、スルホン酸基を有する重合体、離型剤、荷電制御剤、場合によって着色剤等トナーとして必要な成分及びその他の添加剤等をヘンシェルミキサー、ボールミル等の混合器により十分混合してから加熱ロール、ニーダー、エクストルーダーの如き熱混練機を用いて溶融混練して樹脂類をお互いに相溶せしめた中に磁性粉体等の他のトナー材料を分散又は溶解せしめ、冷却固化、粉砕後、分級、必要に応じて表面処理を行ってトナー粒子を得、必要に応じて微粉体等を添加混合することによって本発明のトナーを得ることができる。分級及び表面処理の順序はどちらが先でもよい。分級工程においては生産効率上、多分割分級機を用いることが好ましい。粉砕工程は、機械衝撃式、ジェット式等の公知の粉砕装置を用いた方法により行うことができる。本発明に係わる特定の円形度を有するトナーを得るためには、さらに熱をかけて粉砕したり、あるいは補助的に機械的衝撃を加える処理をすることが好ましい。また、微粉砕（必要に応じて分級）されたトナー粒子を熱水中に分散させる湯浴法や熱気流中を通過させる方法などを用いても良い。
【０１３６】
機械的衝撃力を加える手段としては、例えば川崎重工社製のクリプトロンシステムやターボ工業社製のターボミル等の機械衝撃式粉砕機を用いる方法、また、ホソカワミクロン社製のメカノフュージョンシステムや奈良機械製作所製のハイブリダイゼーションシステム等の装置のように、高速回転する羽根によりトナーをケーシングの内側に遠心力により押しつけ、圧縮力・摩擦力等の力によりトナーに機械的衝撃力を加える方法が挙げられる。
【０１３７】
機械的衝撃法を用いる場合においては、処理温度をトナーのガラス転移点Ｔｇ付近の温度（Ｔｇ±１０℃）を加える熱機械的衝撃が、凝集防止や生産性の観点から好ましい。さらに好ましくは、トナーのガラス転移点Ｔｇ±５℃の範囲の温度で行うことが、転写効率を向上させるのに特に有効である。
【０１３８】
さらにまた、本発明のトナーは、特公昭５６−１３９４５号公報等に記載のディスク又は多流体ノズルを用い溶融混合物を空気中に霧化し球状トナーを得る方法や、単量体には可溶で得られる重合体が不溶な水系有機溶剤を用い直接トナーを生成する分散重合方法又は水溶性極性重合開始剤存在下で直接重合しトナーを生成するソープフリー重合方法に代表される乳化重合方法等を用いトナーを製造する方法でも製造が可能である。
【０１３９】
本発明のトナーを粉砕法により製造する場合の結着樹脂としては、ポリスチレン、ポリビニルトルエンなどのスチレン及びその置換体の単重合体；スチレン−プロピレン共重合体、スチレン−ビニルトルエン共重合体、スチレン−ビニルナフタリン共重合体、スチレン−アクリル酸メチル共重合体、スチレン−アクリル酸エチル共重合体、スチレン−アクリル酸ブチル共重合体、スチレン−アクリル酸オクチル共重合体、スチレン−アクリル酸ジメチルアミノエチル共重合体、スチレン−メタクリル酸メチル共重合体、スチレン−メタクリル酸エチル共重合体、スチレン−メタクリル酸ブチル共重合体、スチレン−メタクリル酸ジメチルアミノエチル共重合体、スチレン−ビニルメチルエーテル共重合体、スチレン−ビニルエチルエーテル共重合体、スチレン−ビニルメチルケトン共重合体、スチレン−ブタジエン共重合体、スチレン−イソプレン共重合体、スチレン−マレイン酸共重合体、スチレン−マレイン酸エステル共重合体などのスチレン系共重合体；ポリメチルメタクリレート、ポリブチルメタクリレート、ポリ酢酸ビニル、ポリエチレン、ポリプロピレン、ポリビニルブチラール、シリコーン樹脂、ポリエステル樹脂、ポリアミド樹脂、エポキシ樹脂、ポリアクリル酸樹脂、ロジン、変性ロジン、テルペン樹脂、フェノール樹脂、脂肪族または脂環族炭化水素樹脂、芳香族系石油樹脂、パラフィンワックス、カルナバワックスなどが単独或いは混合して使用できる。特に、スチレン系共重合体及びポリエステル樹脂が現像特性や定着性等の点で好ましい。
【０１４０】
本発明のトナーは、流動化剤として平均一次粒子径４〜８０ｎｍの無機微粉末が、トナー全体に対し０．１〜４質量％添加されていることも非常に好ましい使用形態である。無機微粉末は、トナーの流動性改良及びトナー母粒子の帯電均一化のために添加されるが、無機微粉末を疎水化処理するなどの処理によってトナーの帯電量の調整、環境安定性の向上等の機能を付与することも好ましい。
【０１４１】
無機微粉末の平均一次粒子径が８０ｎｍよりも大きい場合、良好なトナーの流動性が得られず、トナー粒子への帯電付与が不均一になり易く、低湿下での摩擦帯電性の不均一化につながるため、カブリの増大、画像濃度の低下あるいは耐久性の低下等の問題を避けられない。無機微粉末の平均一次粒径が４ｎｍよりも小さい場合には、無機微粒子どうしの凝集性が強まり、一次粒子ではなく解砕処理によっても解れ難い強固な凝集性を持つ粒度分布の広い凝集体として挙動し易く、この凝集体の現像、像担持体或いはトナー担持体等を傷つけること、などによる画像欠陥を生じ易くなる。トナー粒子の帯電分布をより均一とするためには、無機微粉末の平均一次粒径は６〜３５ｎｍであることがより良い。
【０１４２】
無機微粉末の平均一次粒子径は、走査型電子顕微鏡により拡大撮影したトナーの写真で、更に走査型電子顕微鏡に付属させたＸＭＡ等の元素分析手段によって無機微粉末の含有する元素でマッピングされたトナーの写真を対照しつつ、トナー表面に付着或いは遊離して存在している無機微粉末の一次粒子を１００個以上測定し、個数平均径を求めることで測定法できる。
【０１４３】
また、無機微粉末の含有量は、蛍光Ｘ線分析を用い、標準試料から作成した検量線を用いて定量できる。
【０１４４】
本発明のトナーに添加する無機微粉末としては、シリカ，アルミナ，チタニアなどが使用できる。
【０１４５】
例えば、シリカとしては、ケイ素ハロゲン化物の蒸気相酸化により生成されたいわゆる乾式法又はヒュームドシリカと称される乾式シリカ、及び水ガラス等から製造されるいわゆる湿式シリカの両者が使用可能であるが、表面及びシリカ微粉体の内部にあるシラノール基が少なく、またＮａ_２Ｏ，ＳＯ_３ ^２−等の製造残滓の少ない乾式シリカの方が好ましい。また乾式シリカにおいては、製造工程において例えば、塩化アルミニウム，塩化チタン等他の金属ハロゲン化合物をケイ素ハロゲン化合物と共に用いることによって、シリカと他の金属酸化物の複合微粉体を得ることも可能でありそれらも包含する。
【０１４６】
こういった平均一次粒径が４〜８０ｎｍの無機微粉末の添加量は、トナー母粒子１００質量部に対して０．１〜４．０質量部であることが好ましく、添加量が０．１質量部未満ではその効果が十分ではなく、４．０質量部を超えると定着性が悪くなる。
【０１４７】
無機微粉末は、疎水化処理されたものであることが高湿環境下での特性を向上させる点から好ましい。トナーに添加された無機微粉末が吸湿すると、トナーとしての帯電量が著しく低下し、現像性や転写性の低下が生じ易くなる。
【０１４８】
疎水化処理の処理剤としては、シリコーンワニス、各種変性シリコーンワニス、シリコーンオイル、各種変性シリコーンオイル、シラン化合物、シランカップリング剤、その他有機硅素化合物、有機チタン化合物の如き処理剤を単独で或いは併用して処理しても良い。
【０１４９】
その中でも、シリコーンオイルにより処理したものが好ましく、より好ましくは、無機微粉末を疎水化処理すると同時或いは処理した後に、シリコーンオイルにより処理したものが高湿環境下でもトナー粒子の帯電量を高く維持し、選択現像性を低減する上でよい。
【０１５０】
無機微粉末の処理条件としては、例えば第一段反応としてシリル化反応を行い表面の活性水素基を化学結合により消失させた後、第二段反応としてシリコーンオイルにより表面に疎水性の薄膜を形成することができる。シリル化剤の使用量としては、無機微粉末１００質量部に対し５〜５０質量部が好ましい。５質量部未満では無機微粒子表面の活性水素基を消失させるのに十分でなく、５０質量部を超えると余分なシリル化剤どうしの反応で生成するシロキサン化合物が糊の役割となって無機微粒子どうしの凝集が起こり、画像欠陥を生じ易くなる。
【０１５１】
上記シリコーンオイルは、２５℃における粘度が１０〜２００，０００ｍｍ^２／ｓのものが、さらには３，０００〜８０，０００ｍｍ^２／ｓのものが好ましい。１０ｍｍ^２／ｓ未満では、無機微粉末に安定性が無く、熱および機械的な応力により、画質が劣化する傾向がある。２００，０００ｍｍ^２／ｓを超える場合は、均一な処理が困難になる傾向がある。
【０１５２】
シリコーンオイルの処理方法としては、例えばシラン化合物で処理された無機微粉末とシリコーンオイルとをヘンシェルミキサー等の混合機を用いて直接混合してもよいし、無機微粉末にシリコーンオイルを噴霧する方法を用いてもよい。あるいは適当な溶剤にシリコーンオイルを溶解あるいは分散せしめた後、無機微粉末を加え混合し溶剤を除去する方法でもよい。無機微粉末の凝集体の生成が比較的少ない点で噴霧機を用いる方法がより好ましい。
【０１５３】
シリコーンオイルの処理量は無機微粉末１００質量部に対し１〜２３質量部、好ましくは５〜２０質量部が良い。シリコーンオイルの量が少なすぎると良好な疎水性が得られず、多すぎるとやはり無機微粒子の凝集が起こりやすい。
【０１５４】
本発明のトナーには、クリーニング性向上等の目的で、一次粒径３０ｎｍを超える（好ましくは比表面積が５０ｍ^２／ｇ未満）、より好ましくは一次粒径５０ｎｍ以上（好ましくは比表面積が３０ｍ^２／ｇ未満）の無機又は有機の球状に近い微粒子をさらに添加することも好ましい形態のひとつである。例えば球状シリカ粒子、球状ポリメチルシルセスキオキサン粒子、球状樹脂粒子等が好ましく用いられる。
【０１５５】
本発明に用いられる現像剤には、実質的な悪影響を与えない範囲内で更に他の添加剤、例えばポリフッ化エチレン粉末、ステアリン酸亜鉛粉末、ポリフッ化ビニリデン粉末の如き滑剤粉末；あるいは酸化セリウム粉末、炭化硅素粉末、チタン酸ストロンチウム粉末などの研磨剤；あるいは例えば酸化チタン粉末、酸化アルミニウム粉末などの流動性付与剤；ケーキング防止剤；また、逆極性の有機微粒子及び無機微粒子を現像性向上剤として少量用いることもできる。これらの添加剤も表面を疎水化処理して用いることも可能である。
【０１５６】
次に、本発明に用いる画像形成方法および装置ユニットに関して図面を用いて説明する。
【０１５７】
本発明の画像形成方法における現像工程の条件としては、トナー担持体と静電潜像担持体である感光体表面とが接触しているいわゆる接触一成分現像法でも、非接触でトナーをトナー担持体から感光体へ飛翔させる非接触一成分現像法でもどちらにも適用することができ、特に限定されることはない。
【０１５８】
本発明を、接触一成分現像方式でおこなう場合、トナー担持体としては弾性ローラーを用い、弾性ローラー表面等にトナーをコーティングしこれを感光体表面と接触させる方法を用いることができる。この場合、トナーを介して感光体と感光体表面に対向する弾性ローラー間に働く電界によって現像が行われる。従って弾性ローラー表面あるいは、表面近傍が電位をもち、感光体表面とトナー担持表面の狭い間隙で電界を有する必要性がある。このため、弾性ローラーの弾性ゴムが中抵抗領域に抵抗制御されて感光体表面との導通を防ぎつつ電界を保つか、または導電性ローラーの表面層に薄層の絶縁層を設ける方法も利用できる。さらには、導電性ローラー上に感光体表面に対向する側を絶縁性物質により被覆した導電性樹脂スリーブあるいは、絶縁性スリーブで感光体に対向しない側に導電層を設けた構成も可能である。また、トナー担持体として剛体ローラーを用い、感光体をベルトのごときフレキシブルな物とした構成も可能である。トナー担持体としての現像ローラーの抵抗としては１０^２〜１０^９Ω・ｃｍの範囲が好ましい。
【０１５９】
トナー担持体の表面形状としては、その表面粗度Ｒａ（μｍ）を０．２〜３．０となるように設定すると、高画質及び高耐久性を両立できる。該表面粗度Ｒａはトナー搬送能力及びトナー帯電能力と相関する。該トナー担持体の表面粗度Ｒａが３．０を超えると、該トナー担持体上のトナー層の薄層化が困難となるばかりか、トナーの帯電性が改善されないので画質の向上は望めない。３．０以下にすることでトナー担持体表面のトナーの搬送能力を抑制し、該トナー担持体上のトナー層を薄層化すると共に、該トナー担持体とトナーの接触回数が多くなるため、該トナーの帯電性も改善されるので相乗的に画質が向上する。一方、表面粗度Ｒａが０．２よりも小さくなると、トナーコート量の制御が難しくなる。
【０１６０】
本発明において、トナー担持体の表面粗度Ｒａは、ＪＩＳ表面粗さ「ＪＩＳＢ０６０１」に基づき、表面粗さ測定器（サーフコーダＳＥ−３０Ｈ、株式会社小坂研究所社製）を用いて測定される中心線平均粗さに相当する。具体的には、粗さ曲線からその中心線の方向に測定長さａとして２．５ｍｍの部分を抜き取り、この抜き取り部分の中心線をＸ軸、縦倍率の方向をＹ軸、粗さ曲線をｙ＝ｆ（ｘ）で表したとき、次式によって求められる値をマイクロメートル（μｍ）で表したものを言う。
【０１６１】
【数４】

【０１６２】
本発明の画像形成方法においては、トナー担持体は感光体の周速同方向に回転していてもよいし、逆方向に回転していてもよい。その回転が同方向である場合、トナー担持体の周速を感光体の周速に対し１．０５〜３．０倍となるように設定することが好ましい。
【０１６３】
トナー担持体の周速が、感光体の周速に対し１．０５倍未満であると、感光体上のトナーの受ける撹拌効果が不十分となり、良好な画像品質が望めない。また、周速比が３．０を超える場合には、機械的ストレスによるトナーの劣化やトナー担持体へのトナー固着が発生・促進され、好ましくない。
【０１６４】
感光体としては、ａ−Ｓｅ、Ｃｄｓ、ＺｎＯ_２、ＯＰＣ、ａ−Ｓｉの様な光導電絶縁物質層を持つ感光ドラムもしくは感光ベルトが好適に使用される。ＯＰＣ感光体における有機系感光層の結着樹脂は、特に限定するものではない。
【０１６５】
中でもポリカーボネート樹脂、ポリエステル樹脂、アクリル系樹脂が特に、転写性に優れ、感光体へのトナーの融着、外添剤のフィルミングが起こりにくいため好ましい。
【０１６６】
次に本発明の画像形成方法を添付図面を参照しながら以下に説明する。
【０１６７】
図１において、１００は現像装置、１０９は感光体、１０５は紙などの被転写体、１０６は転写部材、１０７は定着用加圧ローラー、１０８は定着用加熱ローラー、１１０は感光体１０９に接触して直接帯電を行う一次帯電部材を示す。
【０１６８】
一次帯電部材１１０には、感光体１０９表面を一様に帯電するようにバイアス電源１１５が接続されている。
【０１６９】
現像装置１００はトナー１０４を収容しており、感光体１０９と接触して矢印方向に回転するトナー担持体１０２を具備する。さらに、トナー量規制及び帯電付与のための現像ブレード１０１と、トナー１０４をトナー担持体１０２に付着させかつトナー担持体１０２との摩擦でトナーへの帯電付与を行うため矢印方向に回転する塗布ローラー１０３も備えている。トナー担持体１０２には現像バイアス電源１１７が接続されている。塗布ローラー１０３にも図示しないバイアス電源が接続されており、負帯電性トナーを使用する場合は現像バイアスよりも負側に、正帯電性トナーを使用する場合は現像バイアスよりも正側に電圧が設定される。
【０１７０】
転写部材１０６には感光体１０９と反対極性の転写バイアス電源１１６が接続されている。
【０１７１】
ここで、感光体１０９とトナー担持体１０２の接触部分における回転方向の長さ、いわゆる現像ニップ幅は０．２ｍｍ以上８．０ｍｍ以下が好ましい。０．２ｍｍ未満では現像量が不足して満足な画像濃度が得られず、転写残トナーの回収も不十分となる。８．０ｍｍを超えてしまうと、トナーの供給量が過剰となり、カブリ抑制が悪化しやすく、また、感光体の摩耗にも悪影響を及ぼす。
【０１７２】
トナー担持体としては、表面に弾性層を有する、いわゆる弾性ローラーが好ましく用いられる。
【０１７３】
使用される弾性層の材料の硬度としては、３０〜６０度（ａｓｋｅｒ−Ｃ／荷重１ｋｇ）のものが好適に使用される。
【０１７４】
また、トナー担持体の抵抗としては、体積抵抗値で１０^２〜１０^９Ωｃｍ程度の範囲が好ましい。１０^２Ωｃｍよりも低い場合、例えば感光体１０９の表面にピンホール等がある場合、過電流が流れる恐れがある。反対に１０^９Ωｃｍよりも高い場合は、摩擦帯電によるトナーのチャージアップが起こりやすく、画像濃度の低下を招きやすい。
【０１７５】
トナー担持体上のトナーコート量は、０．１〜１．５ｍｇ／ｃｍ^２が好ましい。０．１ｍｇ／ｃｍ^２よりも少ないと十分な画像濃度が得にくく、１．５ｍｇ／ｃｍ^２よりも多くなると個々のトナー粒子全てを均一に摩擦帯電することが難しくなり、カブリ抑制の悪化の要因となる。さらに、０．２〜０．９ｍｇ／ｃｍ^２がより好ましい。
【０１７６】
トナーコート量は現像ブレード１０１により制御されるが、この現像ブレード１０１はトナー層を介してトナー担持体１０２に接触している。この時の接触圧は、４．９〜４９Ｎ／ｍ（５〜５０ｇｆ／ｃｍ）が好ましい範囲である。４．９Ｎ／ｍよりも小さいとトナーコート量の制御に加え均一な摩擦帯電も難しくなり、カブリ抑制の悪化等の原因となる。一方、４９Ｎ／ｍよりも大きくなるとトナー粒子が過剰な負荷を受けるため、粒子の変形や現像ブレードあるいはトナー担持体へのトナーの融着等が発生しやすくなり、好ましくない。
【０１７７】
規制部材の自由端部は、好ましいＮＥ長を与える範囲であればどのような形状でもよく、例えば断面形状が直線状のもの以外にも、先端近傍で屈曲したＬ字形状のものや、先端近傍が球状に膨らんだ形状のもの等が好適に用いられる。
【０１７８】
トナーコート量の規制部材としては、トナーを圧接塗布するための弾性ブレード以外にも、剛性のある金属ブレード等を用いても良い。
【０１７９】
弾性の規制部材には、所望の極性にトナーを帯電させるのに適した摩擦帯電系列の材質を選択することが好ましく、シリコーンゴム、ウレタンゴム、ＮＢＲの如きゴム弾性体、ポリエチレンテレフタレートの如き合成樹脂弾性体、ステンレス、鋼、リン青銅の如き金属弾性体が使用できる。また、それらの複合体であっても良い。
【０１８０】
また、弾性の規制部材とトナー担持体に耐久性が要求される場合には、金属弾性体に樹脂やゴムをスリーブ当接部に当たるように貼り合わせたり、コーティング塗布したものが好ましい。
【０１８１】
更に、弾性の規制部材中に有機物や無機物を添加してもよく、溶融混合させても良いし、分散させても良い。例えば、金属酸化物、金属粉、セラミックス、炭素同素体、ウィスカー、無機繊維、染料、顔料、界面活性剤などを添加することにより、トナーの帯電性をコントロールできる。特に、弾性体がゴムや樹脂等の成型体の場合には、シリカ、アルミナ、チタニア、酸化錫、酸化ジルコニア、酸化亜鉛等の金属酸化物微粉末、カーボンブラック、一般にトナーに用いられる荷電制御剤等を含有させることも好ましい。
【０１８２】
またさらに、規制部材に直流電場及び／または交流電場を印加することによっても、トナーへのほぐし作用のため、均一薄層塗布性、均一帯電性がより向上し、充分な画像濃度の達成及び良質の画像を得ることができる。
【０１８３】
図１において、一次帯電部材１１０は、矢印方向に回転する感光体１０９を一様に帯電する。
【０１８４】
ここで用いている一次帯電部材は、中心の芯金１１０ｂとその外周を形成した導電性弾性層１１０ａとを基本構成とする帯電ローラーである。帯電ローラー１１０は、静電潜像担持体一面に押圧力を持って当接され、静電潜像担持体１０９の回転に伴い従動回転する。
【０１８５】
帯電ローラーを用いたときの好ましいプロセス条件としては、ローラーの当接圧が４．９〜４９０Ｎ／ｍ（５〜５００ｇｆ／ｃｍ）であり、印加電圧としては直流電圧あるいは直流電圧に交流電圧を重畳したもの等が用いられ、特に限定されないが、本発明においては直流電圧のみの印加電圧が好適に用いられ、この場合の電圧値としては±０．２〜±５ｋＶの範囲で使用される。
【０１８６】
この他の帯電手段としては、帯電ブレードを用いる方法や、導電性ブラシを用いる方法がある。これらの接触帯電手段は、非接触のコロナ帯電に比べて、高電圧が不必要になったり、オゾンの発生が低減するといった効果がある。接触帯電手段としての帯電ローラーおよび帯電ブレードの材質としては、導電性ゴムが好ましく、その表面に離型性被膜を設けても良い。離型性被膜としては、ナイロン系樹脂、ＰＶＤＦ（ポリフッ化ビニリデン）、ＰＶＤＣ（ポリ塩化ビニリデン）などが適用可能である。
【０１８７】
一次帯電工程に次いで、発光素子からの露光１２３によって感光体１０９上に情報信号に応じた静電潜像を形成し、トナー担持体１０２と当接する位置においてトナーにより静電潜像を現像し可視像化する。さらに、本発明の画像形成方法において、特に感光体上にデジタル潜像を形成した現像システムと組み合わせることで、潜像を乱さないためにドット潜像に対して忠実に現像することが可能となる。該可視像は転写部材１０６により被転写体１０５に転写され、加熱ローラー１０８と加圧ローラー１０７の間を通過して定着され、永久画像を得る。なお、加熱加圧定着手段としては、ここに示したハロゲンヒーター等の発熱体を内蔵した加熱ローラーとこれと押圧力をもって圧接された弾性体の加圧ローラーを基本構成とする熱ローラー方式以外に、フィルムを介してヒーターにより加熱定着する方式も用いられる。
【０１８８】
一方、転写されずに感光体１０９上に残った転写残トナーは、感光体１０９の表面に当接されるクリーニングブレードを有するクリーナー１３８で回収され、感光体１０９はクリーニングされる。
【０１８９】
次に、本発明の特徴である、カブリの発生や、濃度安定化を達成するためには必須であるトナー担持体上における、トナーコート層の表面電位について説明する。
【０１９０】
本発明の画像形成方法において、トナー担持体上における、トナーコート層の表面電位は、トナー担持体の回転開始１０秒時の表面電位が−５〜−５０Ｖの範囲内にあることを特徴とする。
【０１９１】
より好ましい範囲は、−７〜−４５Ｖ、更に好ましくは−１０〜−４０Ｖの範囲である。
【０１９２】
回転開始１０秒時における表面電位が−５Ｖに満たない場合、現像し得るトナー層がトナー担持体上に十分に形成されておらず、濃度が安定化するまでにどうしてもウェイトタイムを要するため電子写真システムに不適である。また、仮に−５Ｖ以下の値で安定したとしても、トナーの帯電電位不足によりカブリが悪い。
【０１９３】
一方、−５０Ｖを超える場合は帯電電位過多であり、トナー担持体上で過帯電トナー同士の静電反発によりコート面における帯電分布の均一性や、ひどい場合はコートそのものが乱れるため、ハーフトーン画像の均一性が悪くなる。
【０１９４】
尚、本発明の画像形成方法は、１０秒時の表面電位が−５Ｖ以上で十分な最大濃度は見込まれるが、回転開始１分時における飽和帯電電位が−１０Ｖ〜−５０Ｖより好ましくは−１２Ｖ〜−４０Ｖを満たすことで、安定したハーフトーン均一性や、カブリの少ない高品質画像を約束できる。
【０１９５】
尚、表面電位の測定は、市販のレーザービームプリンタＬＢＰ−２５１０（キヤノン製）のカートリッジＥＰ−８５（キヤノン製）の現像器を空回転機にセットして、周速１８０ｍｍ／ｓｅｃ．で回転したときの１０秒時の値を用いた。具体的には、トナーを２００ｇ装填し、常温常湿条件下（温度２３℃，湿度５０％ＲＨ）で一晩放置し、トナー担持体に１ｍｍのギャップでプローブを対向させ、表面電位計ｍｏｄｅｌ３４４（Ｔｒｅｋ社製）を用いて帯電電位の立ち上がりを計測した。
【０１９６】
メモリハイコーダ（日置電機株式会社製）に読み込ませた電位の立ち上がりの一例を図２に示す（周速１８０ｍｍ／ｓｅｃ．で９０秒間空回転を行った時のプロファイル。）。
【０１９７】
次に、本発明のトナーを用いた画像形成方法及び装置ユニットに関して図面を用いて説明する。
【０１９８】
図３および図４には、本発明の画像形成方法を中間転写体を用いて多重トナー像を記録材に一括転写する画像形成装置の概略図を示す。
【０１９９】
図３には、本発明の画像形成方法を中間転写ドラムを用いて、多重トナー像を記録材に一括転写する画像形成装置の概略図を示す。
【０２００】
潜像担持体としての感光体ドラム１の表面に、帯電部材としての帯電バイアス電圧が印加された回転可能な帯電ローラー２を回転させながら接触させて、感光体ドラム表面を均一に一次帯電し、露光手段としての光源装置Ｌより発せられたレーザー光Ｅにより、感光体ドラム１上に第１の静電潜像を形成する。形成された第１の静電潜像は、回転可能なロータリーユニット１０に設けられている第１の現像器としてブラック現像器４Ｂｋ中のブラックトナーにより現像され、ブラックトナー像を形成する。感光体ドラム１上に形成されたブラックトナー像は、中間転写ドラムの導電性支持体に印加される転写バイアス電圧の作用により、中間転写ドラム５上に静電的に一次転写される。次に、上記と同様にして感光体ドラム１の表面に第２の静電潜像を形成し、ロータリーユニット１０を回転して、第２の現像器としてのイエロー現像器４Ｙ中のイエロートナーにより現像してイエロートナー像を形成し、ブラックトナー像が一次転写されている中間転写ドラム５上にイエロートナー像を静電的に一次転写する。同様にして、第３の静電潜像及び第４の静電潜像をロータリーユニット１０を回転して、第３の現像器としてのマゼンタ現像器４Ｍ中のマゼンタトナー及び第４の現像器としてシアン現像器４Ｃ中のシアントナーにより、順次現像及び一次転写を行って、中間転写ドラム５上に各色のトナー像をそれぞれ一次転写する。中間転写ドラム５上に一次転写された多重トナー像は、記録材Ｐを介して反対側に位置する第２の転写装置８からの転写バイアス電圧の作用により、記録材Ｐの上に静電的に一括に二次転写される。記録材Ｐ上に二次転写された多重トナー像は加熱ローラー及び加圧ローラーを有する定着装置９により記録材Ｐに加熱定着される。転写後に感光体ドラム１の表面上に残存する転写残トナーは、感光体ドラム１の表面に当接するクリーニングブレードを有するクリーナーで回収され、感光体ドラム１はクリーニングされる。
【０２０１】
感光体ドラム１から中間転写ドラム５への一次転写は、第１の転写装置としての中間転写ドラム５の導電性支持体に、図示しない電源よりバイアスを付与することで転写電流が得られ、トナー画像の転写が行われる。
【０２０２】
中間転写ドラム５は、剛体である導電性支持体５ａと、表面を覆う弾性層５ｂよりなる。
【０２０３】
導電性支持体５ａとしては、アルミニウム、鉄、銅及びステンレス等の金属や合金、及びカーボンや金属粒子等を分散した導電性樹脂等を用いることができ、その形状としては円筒状や、円筒の中心に軸を貫通したもの、円筒の内部に補強を施したもの等が挙げられる。
【０２０４】
弾性層５ｂとしては、特に制約されるものではないが、スチレン−ブタジエンゴム、ハイスチレンゴム、ブタジエンゴム、イソプレンゴム、エチレン−プロピレン共重合体、ニトリルブタジエンゴム（ＮＢＲ）、クロロプレンゴム、ブチルゴム、シリコーンゴム、フッ素ゴム、ニトリルゴム、ウレタンゴム、アクリルゴム、エピクロロヒドリンゴム及びノルボルネンゴム等のエラストマーゴムが好適に用いられる。ポリオレフィン系樹脂、シリコーン樹脂、フッ素系樹脂、ポリカーボネート等の樹脂およびこれらの共重合体や混合物を用いても良い。
【０２０５】
また、弾性層のさらに表面に、潤滑性、はっ水性の高い滑剤粉体を任意のバインダー中に分散した表面層を設けても良い。
【０２０６】
滑剤は特に制限はないが、各種フッ素ゴム、フッ素エラストマー、黒鉛やグラファイトにフッ素を結合したフッ化炭素及びポリテトラフルオロエチレン（ＰＴＦＥ）、ポリフッ化ビニルデン（ＰＶＤＦ）、エチレン−テトラフルオロエチレン共重合体（ＥＴＦＥ）及び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（ＰＦＡ）等のフッ素化合物、シリコーン樹脂粒子、シリコーンゴム、シリコーンエラストマー等のシリコーン系化合物、ポリエチレン（ＰＥ）、ポリプロピレン（ＰＰ）、ポリスチレン（ＰＳ）、アクリル樹脂、ポリアミド樹脂、フェノール樹脂及びエポキシ樹脂等が好ましく用いられる。
【０２０７】
また、表面層のバインダー中に、抵抗を制御するために導電剤を適時添加しても良い。導電剤としては、各種の導電性無機粒子及びカーボンブラック、イオン系導電剤、導電性樹脂及び導電性粒子分散樹脂等が挙げられる。
【０２０８】
中間転写ドラム５上の多重トナー像は、第２の転写装置８により記録材Ｐ上に一括に二次転写されるが、転写手段８としてはコロナ帯電器による非接触静電転写手段或いは転写ローラー及び転写ベルトを用いた接触静電転写手段が使用可能である。
【０２０９】
定着装置９としては、加熱ローラー９ａと加圧ローラー９ｂを有する熱ローラー定着装置に替えて、記録材Ｐ上のトナー像に接するフィルムを加熱することにより、記録材Ｐ上のトナー像を加熱し、記録材Ｐに多重トナー像を加熱定着するフィルム加熱定着装置を用いることもできる。
【０２１０】
図３に示した画像形成装置が用いている中間転写体としての中間転写ドラムに代えて、中間転写ベルトを用いて多重トナー像を記録材に一括転写することも可能である。中間転写ベルトの構成について、図４に示す。
【０２１１】
感光ドラム１上に形成担持されたトナー画像は、感光ドラム１と中間転写ベルト４０とのニップ部を通過する過程で、一次転写ローラー４２から中間転写ベルト４０に印加される一次転写バイアスにより形成される電界により、中間転写ベルト４０の外周面に順次一次転写される。
【０２１２】
感光ドラム１から中間転写ベルト４０への第１〜第４色のトナー画像の順次重畳転写のための一次転写バイアスは、トナーとは逆極性で、バイアス電源４４から印加される。
【０２１３】
感光ドラム１から中間転写ベルト４０への第１〜第３色のトナー画像の一次転写工程において、二次転写ローラー４３ｂ及び中間転写ベルトクリーナー４９は中間転写ベルト４０から離間することも可能である。
【０２１４】
４３ｂは二次転写ローラーで、二次転写対向ローラー４３ａに対応し平行に軸受させて中間転写ベルト４０の下面部に離間可能な状態に配設してある。
【０２１５】
中間転写ベルト４０上に転写された合成カラートナー画像の転写材Ｐへの転写は、二次転写ローラー４３ｂが中間転写ベルト４０に当接されると共に、中間転写ベルト４０と二次転写ローラー４３ｂとの当接ニップに所定のタイミングで転写材Ｐが給送され、二次転写バイアスがバイアス電源４６から二次転写ローラー４３ｂに印加される。この二次転写バイアスにより中間転写ベルト４０から転写材Ｐへ合成カラートナー画像が二次転写される。
【０２１６】
転写材Ｐへの画像転写終了後、中間転写ベルト４０にはクリーニング用帯電部材４９が当接され、感光ドラム１とは逆極性のバイアスをバイアス電源４５から印加することにより、転写材Ｐに転写されずに中間転写ベルト４０上に残留しているトナー（転写残トナー）に感光ドラム１と逆極性の電荷が付与される。
【０２１７】
前記転写残トナーは、感光ドラム１とのニップ部およびその近傍において感光ドラム１に静電的に転写されることにより、中間転写体がクリーニングされる。
【０２１８】
中間転写ベルトは、ベルト形状の基層と基層の上に設けられる表面処理層よりなる。なお、表面処理層は複数の層により構成されていても良い。
【０２１９】
基層及び表面処理層には、ゴム、エラストマー、樹脂を使用することができる。例えばゴム、エラストマーとしては、天然ゴム、イソプレンゴム、スチレン−ブタジエンゴム、ブタジエンゴム、ブチルゴム、エチレン−プロピレンゴム、エチレン−プロピレンターポリマー、クロロプレンゴム、クロロスルホン化ポリエチレン、塩素化ポリエチレン、アクリロニトリルブタジエンゴム、ウレタンゴム、シンジオタクチック１，２−ポリブタジエン、エピクロロヒドリンゴム、アクリルゴム、シリコーンゴム、フッ素ゴム、多硫化ゴム、ポリノルボルネンゴム、水素化ニトリルゴム及び熱可塑性エラストマー（例えばポリスチレン系、ポリオレフィン系、ポリ塩化ビニル系、ポリウレタン系、ポリアミド系、ポリエステル系及びフッ素樹脂系等）等からなる群より選ばれる１種類あるいは２種類以上を使用することができる。ただし、上記材料に限定されるものではない。また、樹脂としては、ポリオレフィン系樹脂、シリコーン樹脂、フッ素系樹脂、ポリカーボネート等の樹脂を使用することができる。これら樹脂の共重合体や混合物を用いても良い。
【０２２０】
基層としては上述のゴム、エラストマー、樹脂をフィルム状にして使用することができる。また、これらの物質を、織布形状、不織布形状、糸状、フィルム形状をした芯体層の片面あるいは両面に上述のゴム、エラストマー、樹脂を被覆、浸漬、噴霧したものを使用しても良い。
【０２２１】
芯体層を構成する材料は、例えば綿、絹、麻及び羊毛等の天然繊維；キチン繊維、アルギン酸繊維及び再生セルロース繊維等の再生繊維；アセテート繊維等の半合成繊維；ポリエステル繊維、ナイロン繊維、アクリル繊維、ポリオレフィン繊維、ポリビニルアルコール繊維、ポリ塩化ビニル繊維、ポリ塩化ビニリデン繊維、ポリウレタン繊維、ポリアルキルパラオキシベンゾエート繊維、ポリアセタール繊維、アラミド繊維、ポリフロロエチレン繊維及びフェノール繊維等の合成繊維；炭素繊維、硝子繊維及びボロン繊維等の無機繊維；鉄繊維及び銅繊維等の金属繊維からなる群より選ばれる１種あるいは２種以上を用いることができる。もちろん、上記材料に限定されるものではない。
【０２２２】
さらに、中間転写体の抵抗値を調節するために基層および表面処理層中に導電剤を添加しても良い。導電剤としては特に限定されるものではないが、例えば、カーボン、アルミニウムやニッケル等の金属粉末、酸化チタン等の金属酸化物、及び４級アンモニウム塩含有ポリメタクリル酸メチル、ポリビニルアニリン、ポリビニルピロール、ポリジアセチレン、ポリエチレンイミン、含硼素高分子化合物及びポリピロール等の導電性高分子化合物等からなる群より選ばれる１種あるいは２種以上を用いることができる。ただし、上記導電剤に限定されるものではない。
【０２２３】
また、中間転写体表面の滑り性を上げ、転写性を向上するために必要に応じて滑剤を添加しても良い。
【０２２４】
滑剤は特に制限はないが、各種フッ素ゴム、フッ素エラストマー、黒鉛やグラファイトにフッ素を結合したフッ化炭素及びポリテトラフルオロエチレン（ＰＴＦＥ）、ポリフッ化ビニルデン（ＰＶＤＦ）、エチレン−テトラフルオロエチレン共重合体（ＥＴＦＥ）及び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（ＰＦＡ）等のフッ素化合物、シリコーン樹脂、シリコーンゴム、シリコーンエラストマー等のシリコーン系化合物、ポリエチレン（ＰＥ）、ポリプロピレン（ＰＰ）、ポリスチレン（ＰＳ）、アクリル樹脂、ポリアミド樹脂、フェノール樹脂及びエポキシ樹脂等が好ましく用いられる。
【０２２５】
次に、複数画像形成部にて各色のトナー画像をそれぞれ形成し、これを同一転写材に順次重ねて転写するようにした画像形成方法を図５をもとに説明する。
【０２２６】
ここでは、第１，第２，第３および第４の画像形成部２９ａ，２９ｂ，２９ｃ，２９ｄが並設されており、各画像形成部はそれぞれ専用の静電潜像保持体、いわゆる感光ドラム１９ａ，１９ｂ，１９ｃおよび１９ｄを具備している。
【０２２７】
感光ドラム１９ａ乃至１９ｄはその外周側に潜像形成手段２３ａ，２３ｂ，２３ｃおよび２３ｄ、現像部１７ａ，１７ｂ，１７ｃおよび１７ｄ、転写用放電部２４ａ，２４ｂ，２４ｃおよび２４ｄ、ならびにクリーニング部１８ａ，１８ｂ，１８ｃおよび１８ｄが配置されている。
【０２２８】
このような構成にて、先ず、第１画像形成部２９ａの感光ドラム１９ａ上に潜像形成手段２３ａによって原稿画像における、例えばイエロー成分色の潜像が形成される。該潜像は現像手段１７ａのイエロートナーを有する現像剤で可視画像とされ、転写部２４ａにて、転写材としての記録材Ｓに転写される。
【０２２９】
上記のようにイエロー画像が転写材Ｓに転写されている間に、第２画像形成部２９ｂではマゼンタ成分色の潜像が感光ドラム１９ｂ上に形成され、続いて現像手段１７ｂのマゼンタトナーを有する現像剤で可視画像とされる。この可視画像（マゼンタトナー像）は、上記の第１画像形成部２９ａでの転写が終了した転写材Ｓが転写部２４ｂに搬入されたときに、該転写材Ｓの所定位置に重ねて転写される。
【０２３０】
以下、上記と同様な方法により第３，第４の画像形成部２９ｃ，２９ｄによってシアン色，ブラック色の画像形成が行なわれ、上記同一の転写材Ｓに、シアン色，ブラック色を重ねて転写するのである。このような画像形成プロセスが終了したならば、転写材Ｓは定着部２２に搬送され、転写材Ｓ上の画像を定着する。これによって転写材Ｓ上には多色画像が得られるのである。転写が終了した各感光ドラム１９ａ，１９ｂ，１９ｃおよび１９ｄはクリーニング部１８ａ，１８ｂ，１８ｃおよび１８ｄにより残留トナーを除去され、引き続き行なわれる次の潜像形成のために供せられる。
【０２３１】
なお、上記画像形成装置では、転写材としての記録材Ｓの搬送のために、搬送ベルト２５が用いられており、図５において、転写材Ｓは右側から左側へ搬送され、その搬送過程で、各画像形成部２９ａ，２９ｂ，２９ｃおよび２９ｄにおける各転写部２４ａ，２４ｂ，２４ｃおよび２４ｄを通過し、転写をうける。
【０２３２】
この画像形成方法において、転写材を搬送する搬送手段として加工の容易性及び耐久性の観点からテトロン（登録商標）繊維のメッシュを用いた搬送ベルトおよびポリエチレンテレフタレート系樹脂、ポリイミド系樹脂、ウレタン系樹脂の如き薄い誘電体シートを用いた搬送ベルトが利用される。
【０２３３】
転写材Ｓが第４画像形成部２９ｄを通過すると、ＡＣ電圧が除電器２０に加えられ、転写材Ｓは除電され、ベルト２５から分離され、その後、定着器２２に入り、画像定着され、排出口２６から排出される。
【０２３４】
なお、この画像形成方法では、その画像形成部にそれぞれ独立した静電潜像保持体を具備しており、転写材はベルト式の搬送手段で、順次、各静電潜像保持体の転写部へ送られるように構成してもよい。
【０２３５】
また、この画像形成方法では、その画像形成部に共通する静電潜像保持体を具備してなり、転写材は、ドラム式の搬送手段で、静電潜像保持体の転写部へ繰返し送られて、各色の転写をうけるように構成してもよい。
【０２３６】
しかしながら、この搬送ベルトでは、体積抵抗が高いため、カラー画像形成装置におけるように、数回の転写を繰り返す過程で、搬送ベルトが帯電量を増加させて行く。このため、各転写の都度、転写電流を順次増加させないと、均一な転写を維持できない。
【０２３７】
本発明トナーは転写性が優れているので、転写を繰返す毎に搬送手段の帯電が増しても、同じ転写電流で各転写におけるトナーの転写性を均一化でき、良質な高品位画像が得られることになる。
【０２３８】
図６は、中間転写ドラムを用い中間転写ドラム上に一次転写された４色のカラートナー画像を記録材に一括して二次転写する際の二次転写手段として、転写ベルトを用いた画像形成装置の説明図である。
【０２３９】
図６に示す装置システムにおいて、現像器２４４−１、２４４−２、２４４−３、２４４−４に、それぞれシアントナーを有する現像剤、マゼンタトナーを有する現像剤、イエロートナーを有する現像剤及びブラックトナーを有する現像剤が導入され、感光体２４１に形成された静電荷像を現像し、各色トナー像が感光体２４１上に形成される。感光体２４１はａ−Ｓｅ、Ｃｄｓ、ＺｎＯ_２、ＯＰＣ、ａ−Ｓｉの様な光導電絶縁物質層を持つ感光ドラムもしくは感光ベルトである。感光体２４１は図示しない駆動装置によって矢印方向に回転される。
【０２４０】
感光体２４１としては、アモルファスシリコン感光層、又は有機系感光層を有する感光体が好ましく用いられる。
【０２４１】
有機感光層としては、感光層が電荷発生物質及び電荷輸送性能を有する物質を同一層に含有する、単一層型でもよく、又は、電荷輸送層を電荷発生層を成分とする機能分離型感光層であっても良い。導電性基体上に電荷発生層、次いで電荷輸送層の順で積層されている構造の積層型感光層は好ましい例の一つである。
【０２４２】
有機感光層の結着樹脂はポリカーボネート樹脂、ポリエステル樹脂、アクリル系樹脂が特に、転写性、クリーニング性が良く、クリーニング不良、感光体へのトナーの融着、外添剤のフィルミングが起こりにくい。
【０２４３】
帯電工程では、コロナ帯電器を用いる感光体２４１とは非接触である方式と、ローラー等を用いる接触型の方式がありいずれのものも用いられる。効率的な均一帯電、シンプル化、低オゾン発生化のために図６に示す如く接触方式のものが好ましく用いられる。
【０２４４】
帯電ローラー２４２は、中心の芯金２４２ｂとその外周を形成した導電性弾性層２４２ａとを基本構成とするものである。帯電ローラー２４２は、感光体２４１面に押圧力をもって圧接され、感光体２４１の回転に伴い従動回転する。
【０２４５】
帯電ローラーを用いた時の好ましいプロセス条件としては、ローラーの当接圧が４．９〜４９０Ｎ／ｍ（５〜５００ｇｆ／ｃｍ）で、直流電圧に交流電圧を重畳したものを用いた時には、交流電圧＝０．５〜５ｋＶｐｐ、交流周波数＝５０Ｈｚ〜５ｋＨｚ、直流電圧＝±０．２〜±１．５ｋＶであり、直流電圧を用いた時には、直流電圧＝±０．２〜±５ｋＶである。
【０２４６】
この他の帯電手段としては、帯電ブレードを用いる方法や、導電性ブラシを用いる方法がある。これらの接触帯電手段は、高電圧が不必要になったり、オゾンの発生が低減するといった効果がある。
【０２４７】
接触帯電手段としての帯電ローラー及び帯電ブレードの材質としては、導電性ゴムが好ましく、その表面に離型性被膜をもうけても良い。離型性被膜としては、ナイロン系樹脂、ＰＶＤＦ（ポリフッ化ビニリデン）、ＰＶＤＣ（ポリ塩化ビニリデン）などが適用可能である。
【０２４８】
感光体上のトナー像は、電圧（例えば、±０．１〜±５ｋＶ）が印加されている中間転写ドラム２４５に転写される。転写後の感光体表面は、クリーニングブレード２４８を有するクリーニング手段２４９でクリーニングされる。
【０２４９】
中間転写ドラム２４５は、パイプ状の導電性芯金２４５ｂと、その外周面に形成した中抵抗の弾性体層２４５ａからなる。芯金２４５ｂは、プラスチックのパイプに導電性メッキをほどこしたものでも良い。
【０２５０】
中抵抗の弾性体層２４５ａは、シリコーンゴム、テフロン（登録商標）ゴム、クロロプレンゴム、ウレタンゴム、ＥＰＤＭ（エチレンプロピレンジエンの３元共重合体）などの弾性材料に、カーボンブラック、酸化亜鉛、酸化スズ、炭化ケイ素の如き導電性付与材を配合分散して電気抵抗値（体積抵抗率）を１０^５〜１０^１１Ω・ｃｍの中抵抗に調整した、ソリッドあるいは発泡肉質の層である。
【０２５１】
中間転写ドラム２４５は感光体２４１に対して並行に軸受けさせて感光体２４１の下面部に接触させて配設してあり、感光体２４１と同じ周速度で矢印の反時計方向に回転する。
【０２５２】
感光体２４１の面に形成担持された第１色のトナー像が、感光体２４１と中間転写ドラム２４５とが接する転写ニップ部を通過する過程で中間転写ドラム２４５に対する印加転写バイアスで転写ニップ域に形成された電界によって、中間転写ドラム２４５の外面に対して順次に中間転写されていく。
【０２５３】
必要により、着脱自在なクリーニング手段２８０により、転写材へのトナー像の転写後に、中間転写ドラム２４５の表面がクリーニングされる。中間転写ドラム上にトナー像がある場合、トナー像を乱さないようにクリーニング手段２８０は、中間転写体表面から離される。
【０２５４】
中間転写ドラム２４５に対して並行に軸受けさせて中間転写ドラム２４５の下面部に接触させて転写手段が配設され、転写手段２４７は例えば転写ローラー又は転写ベルトであり、中間転写ドラムと同じ周速度で矢印の時計方向に回転する。転写手段は直接中間転写ドラムと接触するように配設されていても良く、またベルト等が中間転写ドラムと転写手段との間に接触するように配置されても良い。
【０２５５】
転写ローラーの場合、中心の芯金とその外周を形成した導電性弾性層とを基本構成とするものである。
【０２５６】
中間転写ドラム及び転写ローラーとしては、一般的な材料を用いることが可能である。中間転写ドラムの弾性層の体積固有抵抗値よりも転写ローラーの弾性層の体積固有抵抗値をより小さく設定することで転写ローラーへの印加電圧が軽減でき、転写材上に良好なトナー像を形成できると共に転写材の中間転写体への巻き付きを防止することができる。特に中間転写体の弾性層の体積固有抵抗値が転写ローラーの弾性層の体積固有抵抗値より１０倍以上であることが特に好ましい。
【０２５７】
中間転写ドラム及び転写ローラーの硬度は、ＪＩＳ Ｋ−６３０１に準拠し測定される。本発明に用いられる中間転写ドラムは、１０〜４０度の範囲に属する弾性層から構成されることが好ましく、一方、転写ローラーの弾性層の硬度は、中間転写ドラムの弾性層の硬度より硬く４１〜８０度の値を有するものが中間転写ドラムへの転写材の巻き付きを防止する上で好ましい。中間転写ドラムと転写ローラーの硬度が逆になると、転写ローラー側に凹部が形成され、中間転写ドラムへの転写材の巻き付きが発生しやすい。
【０２５８】
図６では中間転写ドラム２４５の下方には、転写ベルト２４７が配置されている。転写ベルト２４７は、中間転写ドラム２４５の軸に対して並行に配置された２本のローラー、すなわちバイアスローラー２４７ａとテンションローラー２４７ｃに掛け渡されており、駆動手段（不図示）によって駆動される。転写ベルト２４７は、テンションローラー２４７ｃ側を中心にしてバイアスローラー２４７ａ側が矢印方向に移動可能に構成されていることにより、中間転写ドラム２４５に対して下方から矢印方向に接離することができる。バイアスローラー２４７ａには、二次転写バイアス源２４７ｄによって所望の二次転写バイアスが印加されており、一方、テンションローラー２４７ｃは接地されている。
【０２５９】
次に、転写ベルト２４７であるが、本実施の形態では、熱硬化性ウレタンエラストマーにカーボンを分散させ厚さ約３００μｍ、体積抵抗率１０^８〜１０^１２Ω・ｃｍ（１ｋＶ印加時）に制御した上に、フッ素ゴム２０μｍ、体積抵抗率１０^１５Ω・ｃｍ（１ｋＶ印加時）に制御したゴムベルトを用いた。その外径寸法は周長８０×幅３００ｍｍのチューブ形状である。
【０２６０】
上述の転写ベルト２４７は、前述のバイアスローラー２４７ａとテンションローラー２４７ｃによって約５％延ばす張力印加がなされている。
【０２６１】
転写手段２４７は中間転写ドラム２４５と等速度或は周速度に差をつけて回転させる。転写材２４６は中間転写ドラム２４５と転写手段２４７との間に搬送されると同時に、転写手段２４７にトナーが有する摩擦電荷と逆極性のバイアスを二次転写バイアス源２４７ｄから印加することによって、中間転写ドラム２４５上のトナー像が転写材２４６の表面側に転写される。
【０２６２】
転写用回転体の材質としては、帯電ローラーと同様のものも用いることができ、好ましい転写のプロセス条件としては、ローラーの当接圧が４．９〜４９０Ｎ／ｍ（５〜５００ｇｆ／ｃｍ）で、直流電圧が±０．２〜±１０ｋＶである。
【０２６３】
例えば、バイアスローラー２４７ａの導電性弾性層２４７ａ１はカーボン等の導電材を分散させたポリウレタン、エチレン−プロピレン−ジエン系三元共重合体（ＥＰＤＭ）等の体積抵抗１０^６〜１０^１０Ωｃｍ程度の弾性体でつくられている。芯金２４７ａ２には定電圧電源によりバイアスが印加されている。バイアス条件としては、±０．２〜±１０ｋＶが好ましい。
【０２６４】
次いで転写材２４６は、ハロゲンヒータ等の発熱体を内蔵させた加熱ローラーとこれと押圧力をもって圧接された弾性体の加圧ローラーとを基本構成とする定着器２８１へ搬送され、加熱ローラーと加圧ローラー間を通過することによってトナー像が転写材に加熱加圧定着される。フィルムを介してヒータにより定着する方法を用いても良い。
【０２６５】
【実施例】
以下、本発明を製造例及び実施例により具体的に説明するが、これは本発明をなんら限定するものではない。なお、以下の配合における部数は全て質量部である。
【０２６６】
（極性重合体１の製造例）
還流管，撹拌機，温度計，窒素導入管，滴下装置及び減圧装置を備えた加圧可能な反応容器に、溶媒としてメタノール２５０部、２−ブタノン１５０部及び２−プロパノール１００部、モノマーとしてスチレン８２部、アクリル酸２−エチルヘキシル１０部、２−アクリルアミド−２−メチルプロパンスルホン酸８部を添加して撹拌しながら還流温度まで加熱した。重合開始剤であるｔ−ブチルペルオキシ−２−エチルヘキサノエート１部を２−ブタノン２０部で希釈した溶液を３０分かけて滴下して５時間撹拌を継続し、更にｔ−ブチルペルオキシ−２−エチルヘキサノエート１部を２−ブタノン２０部で希釈した溶液を３０分かけて滴下して、更に５時間撹拌して重合を終了した。さらに、温度を維持したまま脱イオン水を５００部添加し、有機層と水層の界面が乱れないように毎分８０〜１００回転で２時間撹拌した後に、３０分静置し分層した後に、水層を廃棄し有機層に無水硫酸ナトリウムを添加し、脱水した。
【０２６７】
次に、重合溶媒を減圧留去した後に得られた重合体を１５０メッシュのスクリーンを装着したカッターミルを用いて１００μｍ以下に粗粉砕した。得られた極性重合体はＴｇ約７５℃であった。得られた極性重合体を極性重合体１とする。
【０２６８】
（極性重合体２〜５の製造例）
極性重合体の製造例１において、使用するモノマーの種類・量を表１に示す内容に変更する以外は同様の手法により、極性重合体２〜５を製造した。
【０２６９】
【表１】

【０２７０】
＜実施例１＞
イオン交換水４００部に、０．１Ｍ−Ｎａ_３ＰＯ_４水溶液４５０部を投入し、５０℃に加温した後、ＴＫ式ホモミキサー（特殊機化工業製）を用いて、１０，０００ｒｐｍにて撹拌した。これに１．０Ｍ−ＣａＣｌ_２水溶液６８部を添加し、リン酸カルシウム塩を含む水系媒体を得た。
【０２７１】
一方、
スチレン ８１部
ｎ−ブチルアクリレート １９部
Ｃ．Ｉ．ピグメントブルー１５：３ ５部
極性重合体１ １部
３，５−ジ−ｔ−ブチルサリチル酸のアルミニウム錯体 ０．５部
飽和ポリエステル １０部
（酸価１０ｍｇＫＯＨ／ｇ，ピーク分子量１１，０００）
エステルワックス（吸熱ピーク＝７０℃） １２部
ジビニルベンゼン ０．２部
上記処方を６０℃に加温し、ＴＫ式ホモミキサー（特殊機化工業製）を用いて、６０００ｒｐｍにて均一に溶解・分散した。これに、重合開始剤２，２’−アゾビス（２，４−ジメチルバレロニトリル）３．５部を溶解し、重合性単量体組成物を調製した。
【０２７２】
前記水系媒体中に上記重合性単量体組成物を投入し、６０℃，Ｎ_２雰囲気下において、ＴＫ式ホモミキサーにて１２，０００ｒｐｍで撹拌し、重合性単量体組成物を造粒した。
【０２７３】
その後、パドル撹拌翼で撹拌しつつ、５時間経過時に昇温速度４０℃／Ｈｒで８０℃に昇温し５時間反応させた。重合反応終了後、減圧下で残存モノマーを留去し、冷却後、塩酸を加え、６時間撹拌することで燐酸カルシウム塩を溶解した。
【０２７４】
この後、ろ過、イオン交換水による水洗、乾燥をして、トナー粒子（１）を得た。
【０２７５】
このトナー粒子１００部に対し、流動向上剤として、ヘキサメチルジシラザンで処理した後にシリコーンオイルで処理した疎水性シリカ微粉体（ＢＥＴ：１８０ｍ^２／ｇ）１．５部をヘンシェルミキサー（三井鉱山社製）で５分間乾式混合して、本発明のトナー（１）とした。
【０２７６】
トナー（１）を東亜医用電子株式会社製のフロー式粒子像測定装置を用いて重量平均粒径および平均円形度を算出したところ、それぞれ６．６μｍおよび０．９８５であった。
【０２７７】
表２にトナーの物性値を示す。
【０２７８】
トナー（１）を非磁性一成分系現像剤（１）とし、当該現像剤を図７に示すような画像形成装置を用い、高温高湿度条件下（温度３０℃，湿度８０％ＲＨ）、常温常湿条件下（温度２３℃，湿度５０％ＲＨ）および低温低湿条件下（温度１５℃，湿度１０％ＲＨ）において画像評価を行った。画像形成装置について、以下に説明する。
【０２７９】
図７は、非磁性一成分接触現像方式の電子写真プロセスを利用した、１２００ｄｐｉレーザービームプリンタ（キヤノン製：ＬＢＰ−８４０）改造機の概略図である。本実施例では以下の（ａ）〜（ｇ）の部分を改造した装置を使用した。
【０２８０】
（ａ）装置の帯電方式をゴムローラーを当接して行う直接帯電とし、印加電圧を直流成分（−１２００Ｖ）とした。
【０２８１】
（ｂ）トナー担持体をカーボンブラックを分散したシリコーンゴムからなる中抵抗ゴムローラー（直径１６ｍｍ、硬度ＡＳＫＥＲ−Ｃ４５度、抵抗１０^５Ω・ｃｍ）に変更し、感光体に当接した。
【０２８２】
（ｃ）該トナー担持体の回転周速は、感光体との接触部分において同方向であり、該感光体回転周速に対し１５０％となるように駆動した。
【０２８３】
（ｄ）感光体を以下のものに変更した。
【０２８４】
ここで用いる感光体としてはＡｌシリンダーを基体としたもので、これに以下に示すような構成の層を順次浸漬塗布により積層して、感光体を作製した。
・導電性被覆層：酸化錫及び酸化チタンの粉末をフェノール樹脂に分散したものを主体とする。膜厚１５μｍ。
・下引き層：変性ナイロン及び共重合ナイロンを主体とする。膜厚０．６μｍ。・電荷発生層：長波長域に吸収を持つチタニルフタロシアニン顔料をブチラール樹脂に分散したものを主体とする。膜厚０．６μｍ。
・電荷輸送層：ホール搬送性トリフェニルアミン化合物をポリカーボネート樹脂（オストワルド粘度法による分子量２万）に８：１０の質量比で溶解したものを主体とする。膜厚２０μｍ。
【０２８５】
（ｅ）トナー担持体にトナーを塗布する手段として、現像器内に発泡ウレタンゴムからなる塗布ローラーを設け、該トナー担持体に当接させた。塗布ローラーには、約−５５０Ｖの電圧を印加する。
【０２８６】
（ｆ）該トナー担持体上トナーのコート層制御のために、膜厚３０μｍのポリアミド樹脂をコートした、０．１ｍｍのリン青銅製ブレードを用いた。
【０２８７】
（ｇ）現像時の印加電圧をＤＣ成分（−４５０Ｖ）のみとした。
【０２８８】
該画像形成装置に用いられるトナー担持体と同径、同硬度、同抵抗を有するゴムローラー表面に市販の塗料をごく薄く塗布し、画像形成装置を仮組みしたあと該ゴムローラーを取り外し、光学顕微鏡によりリン青銅ブレード表面を観察し、ＮＥ長を測定した。
【０２８９】
ＮＥ長は１．０５ｍｍであった。
【０２９０】
これらのプロセスカートリッジの改造に適合するよう電子写真装置に以下のように改造及びプロセス条件設定を行った。
【０２９１】
改造された装置はローラー帯電器（直流のみを印加）を用い像担持体を一様に帯電する。帯電に次いで、レーザー光で画像部分を露光することにより静電潜像を形成し、トナーにより可視画像とした後に、電圧を＋７００Ｖ印加したローラーによりトナー像を転写材に転写するプロセスを持つ。
【０２９２】
感光体帯電電位は、暗部電位を−６００Ｖとし、明部電位を−１５０Ｖとした。
【０２９３】
以上の条件で、高温高湿環境（３０℃，８０％ＲＨ）常温常湿環境（２３℃，５０％ＲＨ）および低温低湿環境（１５℃，１０％ＲＨ）の環境下にて２％の印字比率の画像を１００００枚までプリントアウトを行い、１日各環境下に放置した後の一枚目の画像品質を以下に示す方法で評価した。
【０２９４】
（１）画像カブリ
「ＲＥＦＬＥＣＴＭＥＴＥＲ ＭＯＤＥＬ ＴＣ−６ＤＳ」（東京電色社製）により測定したプリントアウト画像の白地部分の白色度と転写紙の白色度の差から、カブリ濃度（％）を算出し、耐久評価終了時の画像カブリを評価した。フィルターは、シアンの場合はアンバーライト、イエローの場合はブルー、マゼンタ及びブラックではグリーンフィルターを用いた。
Ａ：非常に良好 ０．５％未満
Ｂ：良好 ０．５％以上乃至１．０％未満
Ｃ：実用上問題なし １．０％以上乃至１．５％未満
Ｄ：やや難あり １．５％以上
尚、本発明では、Ｃランク以上が許容範囲内である。
【０２９５】
（２）ハーフトーン均一性
画像濃度が０．７のハーフトーン画像を、ディザの有無、それぞれ１枚ずつ出力し、その滑らかさを以下の基準で評価した。
Ａ：非常に良好 ディザ無し画像においても非常に均一
Ｂ：良好 ディザ無し画像において僅かに斑が感じられる
Ｃ：実用上問題なし ディザ有り画像において若干緻密さが異なる所がある
Ｄ：やや難あり ディザ有り画像において明らかに濃度が荒れている
【０２９６】
（３）初期濃度変化
通常の複写機用普通紙（７５ｇ／ｍ^２）の転写材を用いて、画出し試験において初期と１０枚目にベタ画像を出力し、その濃度の変化度合いを評価した。
【０２９７】
尚、画像濃度は「マクベス反射濃度計 ＲＤ９１８」（マクベス社製）を用いて、原稿濃度が０．００の白地部分の画像に対する相対濃度を測定した。
Ａ：非常に良好 ０．１未満
Ｂ：良好 ０．１以上、０．１５未満
Ｃ：実用上問題なし ０．１５以上、０．２未満
Ｄ：やや難あり ０．２以上
【０２９８】
＜実施例２＞
添加する極性重合体を極性重合体１から極性重合体２に変え、３，５−ジ−ｔ−ブチルサリチル酸のアルミニウム錯体の添加量を０．７部に変える以外は、実施例１と同様にした。
【０２９９】
＜実施例３＞
添加する極性重合体の種類を極性重合体１から極性重合体３に変え、３，５−ジ−ｔ−ブチルサリチル酸のアルミニウム錯体をジルコニウム錯体に変更し、添加部数を１．０部に変える以外は、実施例１と同様にした。
【０３００】
＜実施例４＞
添加する極性重合体の種類を極性重合体１から極性重合体４に変え、添加部数を０．５質量部に変え、３，５−ジ−ｔ−ブチルサリチル酸のアルミニウム錯体を亜鉛錯体に変更し、添加部数を１．５部に変える以外は、実施例１と同様にした。
【０３０１】
＜実施例５〜６＞
添加する極性重合体の種類と添加量および３，５−ジ−ｔ−ブチルサリチル酸のアルミニウム錯体の添加量を表２に示すように変える以外は、実施例１と同様にした。
【０３０２】
＜実施例７＞
添加する極性重合体の種類と添加量および３，５−ジ−ｔ−ブチルサリチル酸のアルミニウム錯体を鉄錯体に変更し、添加量を表２に示すように変える以外は、実施例１と同様にした。
【０３０３】
＜実施例８＞
実施例１において、添加する着色剤の種類をＣ．Ｉ．ピグメントイエロー９３に変える以外は、実施例１と同様にした。
【０３０４】
＜実施例９＞
実施例１において、添加する着色剤の種類および添加量を、Ｃ．Ｉ．ピグメントレッド１２２を８質量部に変更する以外は実施例１と同様にした。
【０３０５】
＜実施例１０＞
実施例１において、添加する着色剤の種類および添加量を、カーボンブラック（ＤＢＰ吸油量４２ｃｍ^３／１００ｇ、比表面積６０ｍ^２／ｇ）を８部に変更する以外は実施例１と同様にした。
【０３０６】
＜比較例１〜４＞
添加する極性重合体の種類と添加量および３，５−ジ−ｔ−ブチルサリチル酸のアルミニウム錯体の添加量を表２に示すように変える以外は、実施例１と同様にした。
【０３０７】
＜比較例５＞
実施例１において、添加する荷電制御剤を中心金属を有さないベンジルナフトエ酸に変える以外は、実施例１と同様にした。
【０３０８】
＜比較例６＞
実施例１において、添加する着色剤の種類および添加量を、カーボンブラック（ＤＢＰ吸油量４２ｃｍ^３／１００ｇ、比表面積６０ｍ^２／ｇ）を８部に変更し、荷電制御剤をモノアゾ系金属錯体に変える以外は、実施例１と同様にした。
【０３０９】
製造したトナーの物性値を合わせて表２に示す。
【０３１０】
＜実施例１１＞
次に、フルカラーカラープリンターＬＢＰ２５１０（キヤノン製）に［トナーの製造例１で製造したシアントナー］、［トナーの製造例８で製造したイエロートナー］、［トナーの製造例９で製造したマゼンタトナー］、［トナーの製造例１０で製造したブラックトナー］をそれぞれ対応するカートリッジに２００ｇずつ充填し、１００００枚のフルカラー画像評価を実施した。その結果を実施例１に準じて評価した。その結果を表３に示す。
【０３１１】
【表２】

【０３１２】
【表３】

【０３１３】
【発明の効果】
本発明者のトナーは、耐久劣化に非常に優位である硫黄原子を有する高分子化合物タイプの荷電制御樹脂と、帯電立ち上がり性に優れた特定の錯体構造をとる荷電制御剤を併用し、かつ、製造技術を駆使してそれらの存在状態を高度に制御することで、初期時の濃度変化が少なく、環境に左右されることなく長期に亘ってカブリの少ない、高品質な画像を提供することができる。
【図面の簡単な説明】
【図１】本発明の画像形成方法を実施する装置の一例の概略構成図である。
【図２】本発明のトナー担持体上の表面電位プロファイルの一例を示す。
【図３】本発明の画像形成方法を実施する装置の他の例の概略構成図である。
【図４】本発明の画像形成方法を実施する装置の他の例の概略構成図である。
【図５】本発明の画像形成方法を実施する装置の他の例の概略構成図である。
【図６】本発明の画像形成方法を実施する装置の他の例の概略構成図である。
【図７】本発明の実施例で用いた改造機の概略構成図である。
【符号の説明】
１ 感光体
２ 帯電ローラー
４Ｙ 各色現像器
４Ｍ 各色現像器
４Ｂｋ 各色現像器
４Ｃ 各色現像器
５ 中間転写ドラム
５ａ 導電性支持体
５ｂ 弾性層
６ クリーニングブレードを有するクリーナー
７ 転写材トレイ
８ 転写装置
９ 定着装置
９ａ 定着用加熱ローラー
９ｂ 定着用加圧ローラー
１０ ロータリーユニット
１６ａ〜１６ｄ 帯電手段
１７ａ〜１７ｄ 現像手段
１８ａ〜１８ｄ クリーニング手段
１９ａ〜１９ｄ 感光ドラム
２０ 除電器
２２ 定着手段
２３ａ 潜像形成手段
２３ｂ〜２３ｄ 潜像形成手段
２４ａ〜２４ｄ 転写用放電手段
２５ 搬送ベルト
２６ 排出口
２７ 吸着帯電手段
２８ａ〜２８ｄ 分離除電放電手段
２９ａ〜２９ｄ 画像形成部
４０ 中間転写ベルト
４１ ローラー
４２ 一次転写ローラー
４３ａ 二次転写対向ローラー
４３ｂ 二次転写ローラー
４４ 一次転写バイアス電源
４５ バイアス電源
４６ 二次転写バイアス電源
４９ ベルトクリーナー
１００ 現像装置
１０１ 現像ブレード
１０２ トナー担持体
１０３ 塗布ローラー
１０４ トナー
１０５ 被転写体
１０６ 転写部材
１０７ 定着用加圧ローラー
１０８ 定着用加熱ローラー
１０９ 感光体
１１０ 一次帯電部材（帯電ローラー）
１１０ａ 導電性弾性層
１１０ｂ 芯金
１１５ 帯電バイアス電源
１１６ 転写バイアス電源
１１７ 現像バイアス電源
１２３ 露光
１３８ クリーニングブレードを有するクリーナー
２４１ 感光体
２４１ａ 光導電絶縁物質層
２４１ｂ 感光層
２４２ 帯電ローラー
２４２ａ 導電性弾性層
２４２ｂ 芯金
２４３ 露光
２４４ 現像ユニット
２４４−１〜２４４−４ 現像器
２４５ 中間転写ドラム
２４５ａ 中抵抗の弾性体層
２４５ｂ パイプ状の導電性芯金
２４６ 転写材
２４７ 転写手段
２４７ａ バイアスローラー
２４７ａ１ 導電性弾性層
２４７ａ２ 芯金
２４７ｃ テンションローラー
２４７ｄ 二次転写バイアス電源
２４８ クリーニングブレード
２４９ クリーニング手段
２８０ 着脱自在なクリーニング手段
２８１ 定着手段
Ｐ，Ｓ 記録材
Ｌ 光源装置
Ｅ レーザー光[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a toner and an image forming method used in a recording method using an electrophotographic method, an electrostatic recording method, an electrostatic printing method, or the like.
[0002]
[Prior art]
Conventionally, a number of methods are known as electrophotographic methods. In general, an electric latent image is formed on an electrostatic image carrier (hereinafter also referred to as a photoreceptor) by various means using a photoconductive substance. Then, the latent image is developed with toner to make a visible image, and if necessary, the toner image is transferred to a transfer material such as paper, and then the toner image is fixed on the transfer material by heat, pressure, etc. To obtain a copy.
[0003]
As a method of visualizing an electric latent image with toner, a cascade development method, a magnetic brush development method, a pressure development method, a magnetic brush development method using a two-component developer composed of a carrier and a toner, a toner carrier is a photoreceptor. Non-contact one-component development method that causes toner to fly from the toner carrier to the photoreceptor without contact with the toner, contact one-component development method in which the toner carrier is pressed against the photoreceptor and the toner is transferred by an electric field, and a jumping method using magnetic toner Are also used.
[0004]
In recent years, an electrophotographic apparatus such as a printer apparatus has a higher resolution as a technical direction, that is, a conventional one that has been 300 or 600 dpi has become 1200 or 2400 dpi. Accordingly, the development method is also required to have higher definition. In addition, copiers are also becoming more sophisticated, and therefore are moving toward digitalization. Since this method is mainly a method of forming an electrostatic charge image with a laser, it is also proceeding in the direction of high resolution, and here again, a high-resolution and high-definition developing method is required as in the case of a printer. .
[0005]
In order to satisfy the demand for higher image quality and higher resolution, it is essential to reduce the particle size and increase the function of the toner, and a method for producing a toner by a polymerization method, which is advantageous for them, has attracted attention.
[0006]
A toner production method using a polymerization method includes associative aggregation in which an aqueous medium containing emulsion-polymerized resin particles serving as a binder resin component associates and aggregates resin particles, a colorant, a release agent, and the like to a desired particle size. A polymerizable monomer composition in which a colorant, a release agent, a polymerization initiator, and the like are dispersed and dissolved in a toner and a polymerizable monomer serving as a binder resin component is dispersed in an aqueous medium to form desired particles. There are two methods for producing a suspension polymerization toner that undergoes suspension polymerization after being formed into droplets having a diameter.
[0007]
Since the suspension polymerization toner is polymerized in the liquid droplets, its shape is close to a true sphere compared to other production methods, and there are few irregularities, so a toner with a high degree of circularity can be obtained without requiring a post-treatment step. (For example, refer to Patent Document 1). Since toner with a high degree of circularity has good transfer efficiency, it is preferably used to achieve a high-resolution and high-definition electrophotographic system.
[0008]
Furthermore, in the electrophotographic field in the last few years, colorization has been rapidly progressing in machines of all specifications, from home use to business use. Since a color image is formed by appropriately overlapping and developing four color toners of yellow, magenta, cyan, and black, each color toner is required to have higher development characteristics than those of a single color.
[0009]
In order to satisfy high-quality development characteristics, it is necessary to control the toner to an appropriate charge amount that can visualize the latent electrostatic latent image more accurately.
[0010]
In order to control the chargeability of the toner, a charge control agent is generally used. The main charge control agents that are usually used are a compound having a complex structure in which a ligand component is coordinated to a central metal, and a charge site. These are roughly classified into two types of polymer compounds containing polar functional groups.
[0011]
Today, as charge control agents having a complex structure in which a ligand component is coordinated to a central metal known in the art, as a negatively chargeable one, a metal complex salt of a monoazo dye, a metal complex salt of salicylic acid, a naphthoic acid Examples thereof include metal complex salts, metal complex salts of dicarboxylic acids, copper phthalocyanine pigments, and the like (see, for example, Patent Document 2).
[0012]
On the other hand, as a charge control agent for a polymer compound containing a polar functional group serving as a charging site, a monomer containing an acid group such as sulfonic acid or carboxylic acid is used as a negatively chargeable one. ) A polymer compound copolymerized with an acrylate ester or the like is mentioned (for example, see Patent Document 3).
[0013]
Compared with a compound having a complex structure, the polymer compound type charge control agent is superior in terms of durability deterioration and component contamination because of its good compatibility with the binder resin. However, since the dispersibility is too good, the density of charging sites (functional groups) on the toner surface that contributes to the frictional charging of the toner becomes thin, and it is necessary to add a large amount in order to express the desired charge amount. It was.
[0014]
In addition, when a polymer compound type charge control agent is used for toner manufactured by suspension polymerization, the particle size distribution tends to increase with the amount of charge control resin added in the manufacturing process. I found out that there was a limit to it.
[0015]
Above all, the most critical problem of this type of polymer compound type charge control resin is the slow rise of charge. Increasing the amount of charge control resin added only increases the saturated charge amount of the toner and does not improve the arrival time. The layer thickness of the toner coat layer on the toner carrier depends on the rotation time of the toner carrier. As a result, there was a problem in concentration stability.
[0016]
On the other hand, when a charge control agent having a complex structure in which a ligand component is coordinated to the central metal is used, there are some inferior to the polymer compound type charge control resin in terms of dispersibility, but the rise of charge is very Are better. However, considering the stable charging characteristics of the toner, it also contributes greatly to the presence of the charge control agent in the toner, and if the dispersibility is non-uniform or exists on the surface as a lump, the tribo distribution broadens. Development characteristics are significantly deteriorated due to contamination and charging member contamination.
[0017]
Salicylic acid and its derivatives have good dispersibility, and when used in the production of toner by suspension polymerization, it is possible to control the presence of the salicylic acid and its derivatives uniformly on the toner surface due to the effect of polar groups. However, salicylic acid has a tendency that the charge control ability greatly fluctuates with respect to temperature and humidity, and further, the toner is left for a long time. In addition, the salicylic acid metal complex causes significant reversal fog when the complex structure is broken as the toner deteriorates. Therefore, even if salicylic acid or a derivative thereof can be controlled to an optimum state on the toner surface by an advanced production method, the background fogging deteriorates when the amount of the amount is reduced. Since the reverse fog is dramatically worsened during durability or when left unattended, there is a limit to the number of durable sheets in the practical range.
[0018]
On the other hand, there has been proposed a method of stabilizing charging characteristics by complementing each other's drawbacks by using a polymer compound type charge control resin in combination with a charge control agent having a specific structure (for example, (See Patent Documents 4 and 5).
[0019]
However, when the present inventors conducted a follow-up evaluation of these toners in a harsh environment, a slight improvement in the charging characteristics was observed, but in order to effectively exert the control agent effect, the presence in the toner The condition was vital, and there was room for improvement in fog in a high-temperature and high-humidity environment in the latter half of the durability.
[0020]
The toner shown above is intended to improve the chargeability of the pulverized toner, and in the case of using two kinds of charge control agents in a toner that is polymerized in an aqueous system such as suspension polymerization, in terms of production such as granulation property. There was also a problem that had to be technically solved.
[0021]
[Patent Document 1]
JP 2001-343788 A
[Patent Document 2]
JP-A-2-230163
[Patent Document 3]
JP 2000-56548 A
[Patent Document 4]
Japanese Patent Laid-Open No. 2-167565
[Patent Document 5]
JP-A-8-123096
[0022]
[Problems to be solved by the invention]
An object of the present invention is to provide a toner and an image forming method that solve the above-mentioned problems of the prior art.
[0023]
That is, an object of the present invention is to provide a toner and an image forming method capable of providing a high-quality image over a long period of time, exhibiting stable charging characteristics regardless of the environment, and having little image deterioration such as fogging. is there.
[0024]
Another object of the present invention is to provide a toner that has both a quick charge rising property and a quick uniform coating property on the toner carrier, and these functions can be stably exhibited even for a long period of time and after printing a large number of sheets. And providing an image forming method.
[0025]
[Means for Solving the Problems]
As a result of intensive studies on a toner that can achieve a high-definition image with a long life even under harsh environments, the present inventors have found that the polymer compound-type charge control agent is extremely superior in durability deterioration, and has excellent charge rise characteristics. In addition, the present inventors have found a toner that gives a high-quality image over a long period of time without being influenced by the environment by using a compound having a complex structure in combination and highly controlling the existence state of the compound using manufacturing technology.
[0026]
The present invention is a non-magnetic toner comprising at least a binder resin, a colorant, a charge control agent, and a polymer having a sulfur atom,
The charge control agent is a metal compound of an aromatic oxycarboxylic acid, and the contained metal is a metal selected from the group consisting of aluminum, zinc, chromium, cobalt, nickel, zirconium, titanium, copper, and iron. The mass A (mg / g) of oxycarboxylic acid extracted from 1 g of the toner with a 0.1 mol / L sodium hydroxide aqueous solution is A = 0.10 to 3.00 mg / g (toner mass basis) In addition, the ratio (S / C) of the atomic number% (S) of the sulfur element to the atomic number% (C) of the carbon element present on the toner surface measured by X-ray photoelectron spectroscopy is 0.0003 to 0.0050. And
The present invention relates to a non-magnetic toner having an average circularity of 0.955 to 0.995 and a circularity standard deviation of less than 0.035.
[0027]
The present invention also provides an image forming method including a developing step of visualizing the electrostatic latent image by transferring toner to the electrostatic latent image carried on the image carrier by developing means.
The developing means includes a rotatable toner carrier that carries toner and is disposed opposite to the image carrier, and a toner regulating member that regulates the amount of toner on the toner carrier. The surface potential at the start of body rotation 10 seconds is -5 to -50V,
The toner is a non-magnetic toner comprising at least a binder resin, a colorant, a charge control agent, and a polymer having a sulfur atom, and the charge control agent is a metal compound of an aromatic oxycarboxylic acid and is contained. Is a metal selected from the group consisting of aluminum, zinc, chromium, cobalt, nickel, zirconium, titanium, copper and iron, and is extracted from 1 g of the toner with a 0.1 mol / L sodium hydroxide aqueous solution. The mass A (mg / g) of oxycarboxylic acid is A = 0.10 to 3.00 mg / g (toner mass standard), and the atoms of carbon elements present on the toner surface measured by X-ray photoelectron spectroscopy analysis The ratio (S / C) of the atomic number% (S) of the elemental sulfur to the number% (C) is 0.0003 to 0.0050, and the average circularity of the toner is 0.9. In 5 to 0.995, an image forming method, wherein a circularity standard deviation is less than 0.035.
[0028]
DETAILED DESCRIPTION OF THE INVENTION
The toner of the present invention is a nonmagnetic toner comprising at least a binder resin, a colorant, a charge control agent, and a polymer having a sulfur atom, and the charge control agent is a metal compound of an aromatic oxycarboxylic acid, The contained metal is a metal selected from the group consisting of aluminum, zinc, chromium, cobalt, nickel, zirconium, titanium, copper, and iron, and from 1 g of the toner, a 0.1 mol / L sodium hydroxide aqueous solution is used. Extracted oxycarboxylic acid has a mass A (mg / g) of A = 0.10 to 3.00 mg / g (toner mass basis) and carbon present on the toner surface measured by X-ray photoelectron spectroscopy. The ratio (S / C) of the atomic number% (S) of the sulfur element to the atomic number% (C) of the element is 0.0003 to 0.0050, and the average circular diameter of the toner By satisfying the relationship of 0.955 to 0.995 and the circularity standard deviation of less than 0.035, it is possible to satisfactorily control the saturation charge amount and the saturation charge amount arrival time, and to provide charging characteristics suitable for an electrophotographic system. It becomes possible to give.
[0029]
As a result of intensive studies, the present inventors have made the above-described polymer having a sulfonic acid group coexist with a specific metal compound of an aromatic oxycarboxylic acid and highly control the presence state on the toner surface. By using the toner, high-resolution and high-definition images can be formed, and not only at the time of printing out a large number of sheets, but also under severe use conditions such as starting use again after leaving the toner for a long period of time. It has been found that the occurrence of image degradation such as fog and halftone uniformity can be reduced.
[0030]
According to the knowledge of the present inventors, as a characteristic characteristic of the charge control resin having acrylamide methyl propane sulfonic acid as a constituent monomer, which is preferably compatible with the styrene acrylic binder resin, such as after printing a large number of sheets and after standing for a long time Even under adverse conditions, the rise of charge is slow and it is difficult to control the concentration, but there is no non-uniform charge distribution or polarization as seen with charge control agents. We focused on the fact that there is sufficient advantage.
[0031]
Further, the present inventors have found that the salicylic acid complex having a specific central metal has no problem with respect to the arrival time of the saturated charge amount, although the fog characteristic at the time of durability deterioration is very poor.
[0032]
The above two components have fatal problems when used alone, but have succeeded in extracting the merits of the two components more effectively by precisely controlling the amount and state of presence in the toner. . This is achieved by utilizing the interaction of both components by using a suspension polymerization process without using a new dispersing aid or the like.
[0033]
Although it is not necessarily clear about these reasons, the two functions of the charge rising characteristics of the aromatic oxycarboxylic acid having a specific central metal and the deterioration resistance characteristics of the charged site of the polymer having a sulfonic acid group are expressed to the maximum. This is thought to be because the existence state of the charge control agent that could be achieved was achieved. In other words, the existence of a charge control agent that can complement both the weak charge deterioration property of the aromatic oxycarboxylic acid having a specific central metal and the charge rise delay property of the polymer having a sulfonic acid group can be achieved. It is thought that it was made.
[0034]
Even when a polymer charge control resin is used, the reason why the dispersion stability of oil droplets in aqueous systems has increased during suspension polymerization is that aromatic oxycarboxylic acids having specific metals are It tends to segregate in the vicinity of the droplet surface and, depending on the pH, it elutes into an aqueous medium. Therefore, it is considered that it acts suitably as a surfactant on the surface of the toner droplet, and in particular, sulfone compatible with the binder resin. It is believed that the interaction with the acid group promotes suitable droplet stability.
[0035]
In the toner of the present invention, the presence state of these two types of charge control agents that determine charging characteristics on the toner surface, the amount of aromatic oxycarboxylic acid complex having a specific central metal by alkali extraction, and X-ray photoelectron spectroscopy analysis. The amount of surface sulfur element was quantified to define the existence state that can maintain the optimum charging ability in all environments over a long period of time. The stabilization of the toner's charging ability over a long period of time makes it possible to form a stable thin layer that is the same as the initial stage, especially in the non-magnetic one-component development method, and to form a high-resolution, high-definition image without fogging or density fluctuations. It can be carried out.
[0036]
When the mass A of the oxycarboxylic acid having a specific central metal is less than 0.1 mg / g, the charging characteristics of the toner are governed only by the charge control resin, the charge rising property is remarkably inferior, and the thin layer is stable. It takes time to do so, and it takes a wait time to reach an appropriate density, so it cannot be put into practical use as an electrophotographic system. Further, when such toner particles are synthesized by the suspension polymerization method, the droplet stability is poor, the particle size distribution becomes broad, and it is unrealistic considering the classification yield.
[0037]
When A exceeds 3 mg / g, the hygroscopic effect of the metal complex of oxycarboxylic acid present on the toner surface under high temperature and high humidity remarkably inhibits the charging performance, so that the fog immediately after standing for a long time is deteriorated.
[0038]
On the other hand, when the ratio (S / C) of the atomic number% (S) of the sulfur element to the atomic number% (C) of the carbon element existing on the toner surface is less than 0.0003, the charging characteristics of the toner are oxycarboxylic acid It is governed only by the metal complex, and the deterioration of the charging performance accompanying durability cannot be denied.
[0039]
When S / C exceeds 0.0050, a thin layer coat spot called blotch is noticeably generated due to excessive saturation charge amount in a low temperature and low humidity environment, and the halftone reproducibility and the maximum density are reduced. Come on.
[0040]
Furthermore, in order to suitably achieve long-term charging stability and environmental characteristics, which are the objects of the present invention, the charge function of the toner is synergistically controlled by highly controlling the abundance ratio of the two control agents on the toner surface. Improve.
[0041]
That is, the relationship between A and S / C is 3 × 10.^-5<A × S / C <1.5 × 10^-2More preferably 3 × 10^-4<A × S / C <1.4 × 10^-2When satisfying the above range, the charging characteristics are most effectively exhibited.
[0042]
The above relationship is 3 × 10^-5If it is below, the saturation charge amount is small, fogging in a high-temperature and high-humidity environment is poor, and it is difficult to control the concentration when the environment changes.
[0043]
The above relationship is 1.5 × 10^-2If it is as described above, a charge-up tendency is exhibited in a low-temperature and low-humidity environment, and the toner coating property on the toner carrying member becomes non-uniform so that the maximum density cannot be obtained or the half-tone uniformity is deteriorated.
[0044]
In the present invention, the amount A of oxycarboxylic acid extracted from 1 g of toner by a 0.1 mol / liter sodium hydroxide aqueous solution is measured by the following method.
[0045]
That is, 50 ml of a 0.1 mol / liter aqueous sodium hydroxide solution containing 0.04 g of contamination is added as a dispersing agent, 1 g of toner is weighed and added, and stirred at 50 rpm using a stirrer to uniformly disperse. After the dispersion treatment for 3 hours, the mixture is filtered using a membrane filter (pore size: 0.45 μm), and the absorbance of the obtained filtrate is measured. By using a predetermined calibration curve from the obtained results, the mass A (mg) of oxycarboxylic acid extracted from 1 g of toner with a 0.1 mol / liter sodium hydroxide aqueous solution can be obtained.
[0046]
The ratio (S / C) of the sulfur element content (S) to the carbon element content (C) present on the toner particle surface is analyzed by ESCA (X-ray photoelectron spectroscopy) as follows. It can be measured by doing.
[0047]
In the present invention, the ESCA apparatus and measurement conditions are as follows.
Equipment used: 1600S type X-ray photoelectron spectrometer manufactured by PHI
Measurement conditions: X-ray source MgKα (400W)
Spectral region 800μmφ
[0048]
In the present invention, the surface atomic concentration was calculated from the measured peak intensity of each element using a relative sensitivity factor provided by PHI. Specifically, the ratio (S) of the sulfur element content (S) having a peak top at a binding energy of 166 to 172 eV to the carbon element content (C) present on the toner surface as measured by X-ray photoelectron spectroscopy analysis (S / C).
[0049]
In this measurement, it is preferable to measure the toner after ultrasonically washing the toner, removing the external additive adhering to the toner particle surface, separating the toner by means such as filtration, and drying.
[0050]
As the oxycarboxylic acid as a ligand according to the present invention, a known oxycarboxylic acid can be used, but from the viewpoint of charge imparting ability, salicylic acid and alkyl salicylic acid having an alkyl group having 5 or less carbon atoms are preferable. 5-Dialkyl salicylic acid is preferred, and those in which the alkyl group is a t-butyl group are particularly preferred because they have particularly good dispersibility in the resin and charge controllability.
[0051]
Further, as another compound, 2-hydroxy-3-naphthoic acid, alkyl-2-hydroxy-3-naphthoic acid having 5 or less carbon atoms, 5,6,7,8-tetrahalogen-2-hydroxy-3- Naphthoic acid or the like is preferably used.
[0052]
As the central metal of the complex structure, aluminum, zinc, chromium, cobalt, nickel, zirconium, titanium, copper and iron are preferable, and aluminum, zinc, chromium and zirconia are superior in environmental characteristics during durability from the stability of the complex structure. It is more preferable.
[0053]
Specific examples of the metal compound include the following compounds.
[0054]
[Chemical 1]

[0055]
The oxycarboxylic acid having a specific central metal is preferably contained in an amount of 0.1 to 2 parts by mass per 100 parts by mass of the polymerizable monomer. More preferably, it is optimal to contain 0.2 to 1.5 parts by mass, and still more preferably 0.3 to 1.2 parts by mass.
[0056]
When the amount of the complex compound added is less than 0.1 parts by mass, the amount of the complex present on the toner surface is small, and the charging ability is inferior from the initial stage. On the other hand, when the amount is more than 2 parts by mass, the toner surface is excessively present, so that the fog characteristics after durability particularly in a high temperature and high humidity environment are poor.
[0057]
When the toner is obtained by synthesizing the present invention by the suspension polymerization method, the amount of the sulfur atom-containing resin is preferably 0.1 to 2 parts by mass with respect to 100 parts by mass of the binder resin. A more preferable range is 0.2 to 1.5 parts by mass.
[0058]
When the amount of the resin having a sulfur atom added is less than 0.1 parts by mass, the toner surface existing amount of the sulfonic acid group as a charging site is insufficient, and the effect of stabilizing the charge distribution cannot be obtained.
[0059]
On the other hand, if the amount exceeds 2 parts by mass, the droplet stability in the granulation step is deteriorated, and the average circularity and particle size distribution are disturbed.
[0060]
In the toner of the present invention, the content ratio of the polymer (a) having a sulfur atom and the metal compound (b) of the aromatic oxycarboxylic acid is a: b = 90: 10 to 10:90, more preferably The range of 80:20 to 20:80 and the coefficient of variation in the number distribution of the toner is 40 or less, more preferably 35 or less. Later, good halftone reproducibility is achieved.
[0061]
When the said content ratio does not satisfy 90: 10-10: 90, the balance of each charge control function will collapse, and it will be inferior to the charge control capability in long-term durability.
[0062]
When the coefficient of variation exceeds 40, the particle size distribution in the developing machine fluctuates during long-term durability, causing variation in the charge amount of each toner, resulting in narrow fogging and poor durability performance.
[0063]
The content of the resin having a sulfur atom in the toner can be measured using a capillary electrophoresis method or the like.
[0064]
In addition, the coefficient of variation in the number distribution can be obtained by the following equation, and can be measured by a method shown later using a Coulter Counter TA-II type or Coulter Multisizer (manufactured by Coulter Co.).
[0065]
[Expression 1]

[0066]
The resin having a sulfur atom in the present invention has a peak top in a range of 1000 or more in a polystyrene-equivalent molecular weight of gel permeation chromatography described later, and a sulfur element is contained in a component eluted in the above range. It shows what is. The sulfur element valence and bonding state preferably have a peak top at a binding energy of 166 to 172 eV present on the toner surface measured by X-ray photoelectron spectroscopy. Among them, tetravalent or hexavalent is preferable, and hexavalent is more preferable. The bonding state is preferably sulfone, sulfonic acid, sulfonate, sulfate, sulfate ester, etc., and more preferably sulfonate, sulfonate, sulfate, sulfate ester.
[0067]
As the sulfur-containing monomer for producing the resin having a sulfur atom used in the present invention, the resin having a sulfur atom of the present invention includes styrene sulfonic acid, 2-acrylamido-2-methylpropane sulfonic acid, 2- There are methacrylamide-2-methylpropane sulfonic acid, vinyl sulfonic acid, methacryl sulfonic acid and the like, or maleic amide derivatives, maleimide derivatives, and styrene derivatives having the following structures.
[0068]
[Chemical formula 2]

(The binding site is ortho or para.)
[0069]
The resin having a sulfur atom according to the present invention may be a homopolymer of the above monomer, or may be a copolymer of the above monomer and another monomer. As a monomer that forms a copolymer with the above monomer, there is a vinyl polymerizable monomer, and a monofunctional polymerizable monomer or a polyfunctional polymerizable monomer can be used.
[0070]
Among the above monomers, a copolymer having a sulfonic acid is preferable, and a sulfonic acid group-containing (meth) acrylamide is more preferable for obtaining the circularity and a desired average particle diameter of the toner of the present invention.
[0071]
Monofunctional polymerizable monomers include styrene; α-methylstyrene, β-methylstyrene, o-methylstyrene, m-methylstyrene, p-methylstyrene, 2,4-dimethylstyrene, pn-butyl. Styrene, p-tert-butyl styrene, pn-hexyl styrene, pn-octyl styrene, pn-nonyl styrene, pn-decyl styrene, pn-dodecyl styrene, p-methoxy styrene, p -Styrene derivatives such as phenylstyrene; methyl acrylate, ethyl acrylate, n-propyl acrylate, iso-propyl acrylate, n-butyl acrylate, iso-butyl acrylate, tert-butyl acrylate, n-amyl acrylate, n-hexyl acrylate, 2 -Ethylhexyl acrylate , Acrylic polymerizable monomers such as n-octyl acrylate, n-nonyl acrylate, cyclohexyl acrylate, benzyl acrylate, dimethyl phosphate ethyl acrylate, diethyl phosphate ethyl acrylate, dibutyl phosphate ethyl acrylate, 2-benzoyloxyethyl acrylate Methyl methacrylate, ethyl methacrylate, n-propyl methacrylate, iso-propyl methacrylate, n-butyl methacrylate, iso-butyl methacrylate, tert-butyl methacrylate, n-amyl methacrylate, n-hexyl methacrylate, 2-ethylhexyl methacrylate, n-octyl Methacrylate, n-nonyl methacrylate, diethyl phosphate ethyl methacrylate Methacrylic polymerizable monomers such as dibutyl phosphate ethyl methacrylate; methylene aliphatic monocarboxylic acid esters; vinyl esters such as vinyl acetate, vinyl propionate, vinyl butyrate, vinyl benzoate, vinyl formate; vinyl methyl ether Vinyl ether such as vinyl ethyl ether and vinyl isobutyl ether; vinyl ketone such as vinyl methyl ketone, vinyl hexyl ketone and vinyl isopropyl ketone.
[0072]
As polyfunctional polymerizable monomers, diethylene glycol diacrylate, triethylene glycol diacrylate, tetraethylene glycol diacrylate, polyethylene glycol diacrylate, 1,6-hexanediol diacrylate, neopentyl glycol diacrylate, tripropylene glycol Diacrylate, polypropylene glycol diacrylate, 2,2′-bis (4- (acryloxydiethoxy) phenyl) propane, trimethylolpropane triacrylate, tetramethylolmethane tetraacrylate, ethylene glycol dimethacrylate, diethylene glycol dimethacrylate, triethylene glycol Dimethacrylate, tetraethylene glycol dimethacrylate, polyethylene glycol Dimethacrylate, 1,3-butylene glycol dimethacrylate, 1,6-hexanediol dimethacrylate, neopentyl glycol dimethacrylate, polypropylene glycol dimethacrylate, 2,2'-bis (4- (methacryloxy-diethoxy) phenyl) propane, 2,2′-bis (4-methacryloxy / polyethoxy) phenyl) propane, trimethylolpropane trimethacrylate, tetramethylolmethane tetramethacrylate, divinylbenzene, divinylnaphthalene, divinyl ether, and the like.
[0073]
As the resin having a sulfur atom, a monomer as described above can be used, but it is more preferable that the resin contains a styrene derivative.
[0074]
There are bulk polymerization, solution polymerization, emulsion polymerization, suspension polymerization, ionic polymerization and the like as a method for producing a resin having a sulfur atom, but solution polymerization is preferable from the viewpoint of operability.
[0075]
As a monomer constituting the polymer having a sulfonic acid group among resins having a sulfur atom,
X (SO₃ ⁻) N ・ mY^{k +}
(X: represents a polymer site derived from the polymerizable monomer, Y⁺: Represents a counter ion, k is the valence of the counter ion, m and n are integers, and n = k × m. )
It has the following structure. The counter ions are preferably hydrogen ions, sodium ions, potassium ions, calcium ions, ammonium ions and the like.
[0076]
In the resin having a sulfur atom, the acid value (mgKOH / g) of the polymer having a sulfonic acid group is preferably 3 to 50. More preferably, it is 5 to 40.
[0077]
When the acid value is less than 3, sufficient charge control action as mentioned in the present invention cannot be obtained, and environmental characteristics are poor. When the acid value exceeds 50, when particles are produced by suspension polymerization using a composition containing such a polymer, the toner particles have an irregular shape and the circularity decreases. As a result, the contained release agent appears on the surface of the toner, causing a decrease in developability.
[0078]
As for the molecular weight of the resin having a sulfur atom, the weight average molecular weight (Mw) is preferably 2000 to 100,000. When the weight average molecular weight (Mw) is less than 2000, the fluidity of the toner deteriorates and the transferability deteriorates. When it exceeds 100,000, in addition to taking time to dissolve in the monomer, the dispersibility of the pigment also deteriorates and the coloring power of the toner decreases.
[0079]
The glass transition point (Tg) of the resin having a sulfur atom is preferably 50 ° C to 100 ° C. When the glass transition point is less than 50 ° C., the fluidity and storage stability of the toner are inferior, and the transferability is also inferior. When the glass transition point exceeds 100 ° C., the fixability at the time of an image having a high toner printing rate is poor.
[0080]
The volatile content of the resin having sulfur atoms is preferably 0.01% to 2.0%. In order to reduce the volatile content to less than 0.01%, the volatile content removal process becomes complicated, and when the volatile content exceeds 2.0%, charging under high temperature and high humidity, especially charging after standing. It becomes inferior. The polymer volatile content is the ratio of the weight that decreases when heated at high temperature (135 ° C.) for 1 hour.
[0081]
The extraction of the resin having a sulfur atom from the toner is not particularly limited, and any method can be used.
[0082]
The average circularity and circularity standard deviation, which are essential conditions for the toner of the present invention, will be described below.
[0083]
The toner of the present invention must have an average circularity of 0.955 or more and 0.995 or less. Since the toner having an average circularity of 0.955 or more has few edge portions on the surface, it is difficult for the charge to localize within one particle, and the charge amount distribution tends to be sharp. Developed faithfully.
[0084]
On the other hand, toner having an average circularity exceeding 0.995 is not preferable because the circularity is very high and there is a concern about poor cleaning.
[0085]
Furthermore, the toner of the present invention has a circularity standard deviation of the circularity frequency distribution of the toner particles of less than 0.035, preferably less than 0.030, so that a thin layer of toner is formed on the toner carrier. In addition, the toner charge amount can be made appropriate, and uniform thin layer coatability is achieved.
[0086]
When the circularity standard deviation is 0.035 or more, the charge distribution tends to widen, and the latitude such as fog becomes narrow.
[0087]
The average circularity in the present invention is used as a simple method for quantitatively expressing the shape of the particles. In the present invention, the average circularity is measured using a flow type particle image analyzer “FPIA-1000” manufactured by Toa Medical Electronics. The circularity degree (ai) of each particle measured for a particle group having a circle-equivalent diameter of 3 μm or more was determined by the following equation (1), and the total particle size measured by the following equation (2) A value obtained by dividing the sum of the circularity by the total number of particles (m) is defined as the average circularity (a).
[0088]
[Expression 2]

[0089]
[Equation 3]

[0090]
In addition, “FPIA-1000”, which is a measuring apparatus used in the present invention, calculates the circularity of each particle, and then calculates the average circularity. A calculation method is used in which 1.00 is divided into 61 classes and the average circularity is calculated using the center value and frequency of the dividing points. However, the error from each value of the average circularity calculated by this calculation formula is very small and is substantially negligible. In the present invention, the calculation time can be shortened and the calculation formula For reasons of handling data such as simplification, such a calculation formula partially modified by using the concept of the calculation formula that directly uses the circularity of each particle described above may be used.
[0091]
Measuring means are as follows. A dispersion is prepared by dispersing 5 mg of the developer in 10 ml of water in which about 0.1 mg of the surfactant is dissolved, and the dispersion is irradiated with ultrasonic waves (20 KHz, 50 W) for 5 minutes. Measurement is performed with the above apparatus at 20,000 particles / μl, and the average circularity of a particle group having a circle equivalent diameter of 3 μm or more is obtained.
[0092]
The average circularity in the present invention is an index of the degree of unevenness of the developer, and is 1.000 when the developer is a perfect sphere, and the circularity becomes smaller as the surface shape becomes more complicated.
[0093]
In this measurement, the reason why the circularity is measured only for the particle group having an equivalent circle diameter of 3 μm or more is that the particle group of the external additive existing independently of the toner particles in the particle group having an equivalent circle diameter of less than 3 μm. This is because the circularity of the toner particle group cannot be accurately estimated due to the influence of such a large amount.
[0094]
Next, the particle size of the toner will be described.
[0095]
The toner of the present invention preferably has a weight average diameter of 3 μm to 10 μm in order to develop a finer latent image dot faithfully for higher image quality. The weight average diameter of the toner is more preferably 4 μm to 8 μm. In a toner having a weight average diameter of less than 3 μm, fluidity and agitation as a powder are lowered, and it becomes difficult to uniformly charge individual toner particles. This is not preferable for the toner used in the present invention. When the weight average diameter of the toner exceeds 10 μm, the characters and the line image are likely to be scattered, and high resolution is difficult to obtain. Furthermore, as the apparatus becomes higher in resolution, toner of 8 μm or more tends to deteriorate the reproduction of one dot.
[0096]
The weight average particle diameter and number average particle diameter of the toner of the present invention can be measured by various methods such as Coulter Counter TA-II type or Coulter Multisizer (manufactured by Coulter Inc.). Specifically, it can be measured as follows. Using Coulter Multisizer (manufactured by Coulter), an interface (manufactured by Nikka) and a PC9801 personal computer (manufactured by NEC) that output number distribution and volume distribution are connected, and the electrolyte is 1% NaCl using first grade sodium chloride. Adjust the aqueous solution. For example, ISOTON R-II (manufactured by Coulter Scientific Japan) can be used. The measurement procedure is as follows. 100 to 150 ml of the electrolytic aqueous solution is added, and 2 to 20 mg of a measurement sample is further added. The electrolyte in which the sample is suspended is dispersed for about 1 to 3 minutes with an ultrasonic disperser, and the volume and number distribution of toner particles of 2 μm or more are measured by using the aperture with the Coulter Multisizer. And calculate. Then, the volume-based weight average particle diameter (D4) obtained from the volume distribution according to the present invention and the number-based average particle diameter obtained from the number distribution, that is, the number average particle diameter (D1) are obtained.
[0097]
The toner particles of the present invention are preferably particles obtained by a polymerization method. The toner according to the present invention can also be produced by a pulverization method. However, toner particles obtained by this pulverization method are generally amorphous, and the average circularity which is a preferable requirement of the present invention is 0.955. In order to obtain a physical property of ˜0.995, it is necessary to perform mechanical / thermal or some special treatment.
[0098]
Therefore, in order to solve the above-described problems, in the present invention, it is preferable to produce toner particles by a polymerization method. Examples of the toner polymerization method include a direct polymerization method, a suspension polymerization method, an emulsion polymerization method, an emulsion association polymerization method, and a seed polymerization method. Among these, the balance between the particle size and the particle shape is easy to balance. In this respect, it is particularly preferable to produce the suspension by a suspension polymerization method. In this suspension polymerization method, a monomer composition is prepared by uniformly dissolving or dispersing a polymerizable monomer and a colorant (and, if necessary, a polymerization initiator, a crosslinking agent, a charge control agent, and other additives). After that, the monomer composition is dispersed in a continuous layer containing a dispersion stabilizer (for example, an aqueous phase) using a suitable stirrer and simultaneously subjected to a polymerization reaction to obtain a toner having a desired particle size. To get. The toner obtained by this suspension polymerization method (hereinafter, polymerized toner) has toner particles satisfying the physical property requirement that the average circularity is 0.955 to 0.995 or more because individual toner particle shapes are almost spherical. Further, such toner has a high transferability because the distribution of charge amount is relatively uniform.
[0099]
Furthermore, a core / shell structure in which a surface layer is provided by adding a polymerizable monomer and a polymerization initiator again to the fine particles obtained by suspension polymerization can be designed as necessary.
[0100]
The toner of the present invention preferably contains 0.5 to 50 parts by weight of a release agent with respect to 100 parts by weight of the binder resin. Examples of the binder resin include various waxes as will be described later.
[0101]
The toner image transferred onto the transfer material is then fixed on the transfer material with energy such as heat and pressure to obtain a semi-permanent image. At this time, heat roll type fixing and film type fixing are generally used.
[0102]
As described above, if toner particles having a weight average particle size of 10 μm or less can be used, a very high-definition image can be obtained. However, toner particles having a small particle size can be obtained when a transfer material such as paper is used. It enters into the gaps between the fibers, and heat reception from the heat fixing roller becomes insufficient, so that low temperature offset is likely to occur. However, in the toner according to the present invention, by including an appropriate amount of the release agent, it is possible to achieve both high resolution and offset resistance.
[0103]
Release agents usable for the toner according to the present invention include petroleum waxes such as paraffin wax, microcrystalline wax, petrolactam and derivatives thereof, montan wax and derivatives thereof, hydrocarbon waxes and derivatives thereof according to the Fischer-Tropsch method, polyethylene And natural waxes such as carnauba wax and candelilla wax and derivatives thereof. These derivatives include oxides, block copolymers with vinyl monomers, and graft modified products. Furthermore, higher fatty alcohols, fatty acids such as stearic acid and palmitic acid, or compounds thereof, acid amide waxes, ester waxes, ketones, hydrogenated castor oil and derivatives thereof, plant waxes, animal waxes and the like can be mentioned. Among these waxes, those having an endothermic peak in a differential thermal analysis of 40 ° C. to 110 ° C. are preferred, and those having a temperature of 45 ° C. to 90 ° C. are more preferred.
[0104]
As content when using a mold release agent, the range of 0.5-50 mass parts is preferable with respect to 100 mass parts of binder resin. If the content is less than 0.5 parts by mass, the effect of suppressing the low temperature offset is poor, and if it exceeds 50 parts by mass, the long-term storage stability is deteriorated and the dispersibility of other toner materials is deteriorated, and the fluidity of the toner Leading to deterioration and deterioration of image characteristics.
[0105]
The maximum endothermic peak temperature of the wax component is measured according to “ASTM D 3418-8”. For the measurement, for example, DSC-7 manufactured by PerkinElmer is used. The temperature correction of the device detection unit uses the melting points of indium and zinc, and the correction of heat uses the heat of fusion of indium. An aluminum pan is used as a measurement sample, an empty pan is set as a control, and measurement is performed at a heating rate of 10 ° C./min.
[0106]
The glass transition temperature (Tg) of the resin having sulfur atoms is the intersection of the baseline before the endothermic peak and the baseline between the endothermic peak and the rising curve from the DSC curve at the second temperature rise. Tg.
[0107]
The toner of the present invention contains a colorant as an essential component in order to impart coloring power. Examples of the organic pigment or dye preferably used in the present invention include the following.
[0108]
As the organic pigment or organic dye as the cyan colorant, a copper phthalocyanine compound and a derivative thereof, an anthraquinone compound, a basic dye lake compound, or the like can be used. Specifically, C.I. I. Pigment blue 1, C.I. I. Pigment blue 7, C.I. I. Pigment blue 15, C.I. I. Pigment blue 15: 1, C.I. I. Pigment blue 15: 2, C.I. I. Pigment blue 15: 3, C.I. I. Pigment blue 15: 4, C.I. I. Pigment blue 60, C.I. I. Pigment blue 62, C.I. I. And CI Pigment Blue 66.
[0109]
As organic pigments or dyes as magenta colorants, condensed azo compounds, diketopyrrolopyrrole compounds, anthraquinones, quinacridone compounds, basic dye lake compounds, naphthol compounds, benzimidazolone compounds, thioindigo compounds, perylene compounds are used. . Specifically, 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 violet 19, C.I. I. Pigment red 23, C.I. I. Pigment red 48: 2, C.I. I. Pigment red 48: 3, C.I. I. Pigment red 48: 4, C.I. I. Pigment red 57: 1, C.I. I. Pigment red 81: 1, C.I. I. Pigment red 122, C.I. I. Pigment red 144, C.I. I. Pigment red 146, C.I. I. Pigment red 150, C.I. I. Pigment red 166, C.I. I. Pigment red 169, C.I. I. Pigment red 177, C.I. I. Pigment red 184, C.I. I. Pigment red 185, C.I. I. Pigment red 202, C.I. I. Pigment red 206, C.I. I. Pigment red 220, C.I. I. Pigment red 221, C.I. I. And CI Pigment Red 254.
[0110]
As the organic pigment or organic dye as the yellow colorant, compounds represented by condensed azo compounds, isoindolinone compounds, anthraquinone compounds, azo metal complexes, methine compounds, and allylamide compounds are used. Specifically, 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 62, C.I. I. Pigment yellow 74, C.I. I. Pigment yellow 83, C.I. I. Pigment yellow 93, C.I. I. Pigment yellow 94, C.I. I. Pigment yellow 95, C.I. I. Pigment yellow 97, C.I. I. Pigment yellow 109, C.I. I. Pigment yellow 110, C.I. I. Pigment yellow 111, C.I. I. Pigment yellow 120, C.I. I. Pigment yellow 127, C.I. I. Pigment yellow 128, C.I. I. Pigment yellow 129, C.I. I. Pigment yellow 147, C.I. I. Pigment yellow 151, C.I. I. Pigment yellow 154, C.I. I. Pigment yellow 168, C.I. I. Pigment yellow 174, C.I. I. Pigment yellow 175, C.I. I. Pigment yellow 176, C.I. I. Pigment yellow 180, C.I. I. Pigment yellow 181, C.I. I. Pigment yellow 191, C.I. I. And CI Pigment Yellow 194.
[0111]
These colorants can be used alone or mixed and further used in the form of a solid solution. The colorant used in the toner of the present invention is selected from the viewpoints of hue angle, saturation, brightness, light resistance, OHP transparency, and dispersibility in the toner.
[0112]
The colorant is added in an amount of 1 to 20 parts by mass with respect to 100 parts by mass of the binder resin.
[0113]
As the black colorant, carbon black, a magnetic material, and a color toned to black using the yellow / magenta / cyan colorant are used.
[0114]
In the present invention, when a toner is obtained using a polymerization method, it is necessary to pay attention to the polymerization inhibitory property and water phase transfer property of the colorant, and preferably a material that does not inhibit surface modification, for example, polymerization inhibition. It is better to apply a hydrophobizing treatment. In particular, dyes and carbon blacks have many polymerization inhibiting properties, so care must be taken when using them. A preferable method for surface-treating the dye system includes a method in which a polymerizable monomer is polymerized in the presence of these dyes in advance, and the obtained colored polymer is added to the monomer system.
[0115]
Carbon black may be treated with a substance that reacts with the surface functional groups of carbon black, such as polyorganosiloxane, in addition to the same treatment as the above dye.
[0116]
The toner of the present invention may contain a charge control agent as a third component in order to stabilize the charge characteristics. As the charge control agent, a known one can be used, and a charge control agent that has a high charging speed and can stably maintain a constant charge amount is particularly preferable. Further, when the toner is produced using a direct polymerization method, a charge control agent having a low polymerization inhibitory property and substantially free from a solubilized product in an aqueous dispersion medium is particularly preferable. However, addition of a charge control agent is not essential for the toner of the present invention, and the third charge is not necessarily contained in the toner by actively utilizing frictional charging with the toner layer thickness regulating member or the toner carrier. It is not necessary to include a control agent.
[0117]
Next, a method for producing the toner of the present invention by suspension polymerization will be described.
[0118]
When the toner of the present invention is produced by the suspension polymerization method, examples of the polymerizable monomer constituting the polymerizable monomer system to be used include the following.
[0119]
Examples of the polymerizable monomer include styrene monomers such as styrene, o-methylstyrene, m-methylstyrene, p-methylstyrene, p-methoxystyrene, p-ethylstyrene, methyl acrylate, ethyl acrylate, Acrylic esters such as n-butyl acrylate, isobutyl acrylate, n-propyl acrylate, n-octyl acrylate, dodecyl acrylate, 2-ethylhexyl acrylate, stearyl acrylate, 2-chloroethyl acrylate, phenyl acrylate, etc. , Methyl methacrylate, ethyl methacrylate, n-propyl methacrylate, n-butyl methacrylate, isobutyl methacrylate, n-octyl methacrylate, dodecyl methacrylate, 2-ethylhexyl methacrylate, stearyl methacrylate, phenyl methacrylate, Methacrylic acid dimethyl aminoethyl methacrylate esters such as diethylaminoethyl methacrylate and other acrylonitrile-methacrylonitrile-monomer acrylamide.
[0120]
These monomers can be used alone or in combination. Among the above-mentioned monomers, styrene or a styrene derivative is preferably used alone or mixed with other monomers from the viewpoint of the developing characteristics and durability of the toner.
[0121]
In the production of the polymerized toner according to the present invention, a resin may be added to the monomer system for polymerization.
[0122]
For example, a monomer containing a hydrophilic functional group such as an amino group, a carboxylic acid group, a hydroxyl group, a glycidyl group, or a nitrile group that cannot be used because it is soluble in an aqueous suspension and causes emulsion polymerization by dissolving in an aqueous suspension. When it is desired to introduce a body component into the toner, a random copolymer of these with a vinyl compound such as styrene or ethylene, a block copolymer, a graft copolymer, or the like, or in the form of a copolymer, or polyester, polyamide, etc. It can be used in the form of a polyaddition polymer such as a polycondensate, a polyether or a polyimine. When such a polymer containing a polar functional group is allowed to coexist in the toner, the above-mentioned wax component is phase-separated and the encapsulation becomes stronger, and a toner having good offset resistance, blocking resistance, and low-temperature fixability can be obtained. Obtainable.
[0123]
In addition, resins other than those described above may be added to the monomer system for the purpose of improving the dispersibility and fixing properties of the material or image characteristics. Examples of the resin used include styrene such as polystyrene and polyvinyltoluene. And styrene-propylene copolymer, styrene-vinyltoluene copolymer, styrene-vinylnaphthalene copolymer, styrene-methyl acrylate copolymer, styrene-ethyl acrylate copolymer, Styrene-butyl acrylate copolymer, styrene-octyl acrylate copolymer, styrene-dimethylaminoethyl acrylate copolymer, styrene-methyl methacrylate copolymer, styrene-ethyl methacrylate copolymer, styrene-methacrylic acid Acid butyl copolymer, styrene-dimethylaminoethyl methacrylate copolymer Polymer, Styrene-vinyl methyl ether copolymer, Styrene-vinyl ethyl ether copolymer, Styrene-vinyl methyl ketone copolymer, Styrene-butadiene copolymer, Styrene-isoprene copolymer, Styrene-maleic acid copolymer Styrene copolymers such as styrene-maleic acid ester copolymer; polymethyl methacrylate, polybutyl methacrylate, polyvinyl acetate, polyethylene, polypropylene, polyvinyl butyral, silicone resin, polyester resin, polyamide resin, epoxy resin, polyacryl Acid resins, rosins, modified rosins, terpene resins, phenol resins, aliphatic or alicyclic hydrocarbon resins, aromatic petroleum resins and the like can be used alone or in combination.
[0124]
As addition amount of these resin, 1-20 mass parts is preferable with respect to 100 mass parts of monomers. If the amount is less than 1 part by mass, the effect of addition is small, while if it exceeds 20 parts by mass, it becomes difficult to design various physical properties of the polymerized toner.
[0125]
Furthermore, if a polymer having a molecular weight different from the molecular weight range of the toner obtained by polymerizing the monomer is dissolved in the monomer and polymerized, a toner having a wide molecular weight distribution and high offset resistance can be obtained. it can.
[0126]
The polymerization initiator used in the production of the polymerized toner according to the present invention has a half-life of 0.5 to 30 hours at the time of the polymerization reaction, and 0.5 to 20 mass per 100 mass parts of the polymerizable monomer. When the polymerization reaction is carried out with a part addition amount, a polymer having a maximum between 10,000 and 100,000 in molecular weight can be obtained, and the toner can be provided with desirable strength and suitable melting characteristics. Examples of polymerization initiators include 2,2′-azobis- (2,4-dimethylvaleronitrile), 2,2′-azobisisobutyronitrile, 1,1′-azobis (cyclohexane-1-carbonitrile) Azo or diazo polymerization initiators such as 2,2′-azobis-4-methoxy-2,4-dimethylvaleronitrile, azobisisobutyronitrile; benzoyl peroxide, t-butylperoxy 2-ethylhexa Noate, t-butyl peroxypivalate, t-butyl peroxyisobutyrate, t-butyl peroxyneodecanoate, methyl ethyl ketone peroxide, diisopropyl peroxycarbonate, cumene hydroperoxide, 2,4-dichlorobenzoyl Peroxide polymerization such as peroxide and lauroyl peroxide Agents.
[0127]
When the polymerized toner according to the present invention is produced, a crosslinking agent may be added, and a preferable addition amount is 0.001 to 15% by mass.
[0128]
In producing the polymerized toner according to the present invention, a molecular weight modifier can be used. Examples of the molecular weight modifier include mercaptans such as t-dodecyl mercaptan, n-dodecyl mercaptan, n-octyl mercaptan; halogenated hydrocarbons such as carbon tetrachloride and carbon tetrabromide; α-methylstyrene dimer, and the like. Can be mentioned. These molecular weight regulators can be added before the polymerization starts or during the polymerization. The molecular weight modifier is usually used in a proportion of 0.01 to 10 parts by mass, preferably 0.1 to 5 parts by mass with respect to 100 parts by mass of the polymerizable monomer.
[0129]
In the method for producing a polymerized toner according to the present invention, generally, the above-described toner composition, that is, a polymer having a sulfonic acid group in a polymerizable monomer, a release agent, a plasticizer, a charge control agent, a crosslinking agent, The components necessary for the toner, such as colorants, and other additives such as an organic solvent, a high molecular weight polymer, and a dispersant added to reduce the viscosity of the polymer produced by the polymerization reaction are appropriately added, and the homogenizer, ball mill The monomer system uniformly dissolved or dispersed by a dispersing machine such as a colloid mill or an ultrasonic dispersing machine is suspended in an aqueous medium containing a dispersion stabilizer. At this time, the particle size of the obtained toner particles becomes sharper by using a high-speed disperser such as a high-speed stirrer or an ultrasonic disperser to obtain a desired toner particle size at a stretch. The polymerization initiator may be added at the same time when other additives are added to the polymerizable monomer, or may be mixed immediately before being suspended in the aqueous medium. Also, a polymerization initiator dissolved in a polymerizable monomer or solvent can be added immediately after granulation and before starting the polymerization reaction.
[0130]
After granulation, stirring may be performed using a normal stirrer to such an extent that the particle state is maintained and the particles are prevented from floating and settling.
[0131]
In the production of the polymerized toner according to the present invention, known surfactants and organic or inorganic dispersants can be used as dispersion stabilizers. Among them, inorganic dispersants are unlikely to produce harmful ultra fine powders, and due to their steric hindrance. Since the dispersion stability is obtained, the stability is not easily lost even if the reaction temperature is changed, and the toner can be preferably used because it is easily washed and does not adversely affect the toner. Examples of such inorganic dispersants include polyvalent metal phosphates such as calcium phosphate, magnesium phosphate, aluminum phosphate and zinc phosphate, carbonates such as calcium carbonate and magnesium carbonate, calcium metasuccinate, calcium sulfate and barium sulfate. Inorganic oxides such as inorganic salts, calcium hydroxide, magnesium hydroxide, aluminum hydroxide, silica, bentonite and alumina can be mentioned.
[0132]
These inorganic dispersants may be used alone in an amount of 0.2 to 20 parts by mass with respect to 100 parts by mass of the polymerizable monomer, and 0.001 to 0.1 parts by mass for the purpose of adjusting the particle size distribution. These surfactants may be used in combination. Examples of the surfactant include sodium dodecylbenzene sulfate, sodium tetradecyl sulfate, sodium pentadecyl sulfate, sodium octyl sulfate, sodium oleate, sodium laurate, sodium stearate, potassium stearate and the like.
[0133]
When these inorganic dispersants are used, they may be used as they are, but in order to obtain finer particles, the inorganic dispersant particles can be generated in an aqueous medium. For example, in the case of calcium phosphate, a sodium phosphate aqueous solution and a calcium chloride aqueous solution can be mixed with high-speed stirring to produce water-insoluble calcium phosphate, which enables more uniform and fine dispersion. At the same time, water-soluble sodium chloride salt is produced as a by-product. However, if water-soluble salt is present in the aqueous medium, dissolution of the polymerizable monomer in water is suppressed, and ultrafine toner is generated by emulsion polymerization. This is more convenient. Since it becomes an obstacle when removing the remaining polymerizable monomer at the end of the polymerization reaction, it is better to replace the aqueous medium or desalinate with an ion exchange resin. The inorganic dispersant can be almost completely removed by dissolving with an acid or alkali after completion of the polymerization.
[0134]
In the polymerization step, the polymerization is performed at a polymerization temperature of 40 ° C. or higher, generally 50 to 90 ° C. When the polymerization is carried out in this temperature range, the release agent or wax to be sealed inside is precipitated by phase separation, and the encapsulation becomes more complete. In order to consume the remaining polymerizable monomer, the reaction temperature can be increased to 90 to 150 ° C. at the end of the polymerization reaction. The polymerized toner particles are filtered, washed, and dried by a known method after the polymerization is completed, and the toner can be obtained by mixing and adhering the inorganic fine powder to the surface. Moreover, it is also one of desirable forms that a classification process is included in the manufacturing process to cut coarse powder and fine powder.
[0135]
When the toner of the present invention is produced by a pulverization method, a known method is used. For example, as a toner such as a binder resin, a polymer having a sulfonic acid group, a release agent, a charge control agent, and optionally a colorant. The necessary ingredients and other additives are mixed thoroughly using a mixer such as a Henschel mixer or ball mill, and then melt-kneaded using a heat kneader such as a heating roll, kneader or extruder to make the resins compatible with each other. Disperse or dissolve other toner materials such as magnetic powder in the caulking, cool and solidify, pulverize, classify, surface treatment as necessary to obtain toner particles, add fine powder etc. if necessary By mixing, the toner of the present invention can be obtained. Either the classification or the surface treatment may be performed first. In the classification step, it is preferable to use a multi-division classifier in terms of production efficiency. The pulverization step can be performed by a method using a known pulverizer such as a mechanical impact type or a jet type. In order to obtain a toner having a specific degree of circularity according to the present invention, it is preferable to further heat and pulverize or to add a mechanical impact as an auxiliary. Further, a hot water bath method in which finely pulverized (classified as necessary) toner particles are dispersed in hot water, a method of passing in a hot air stream, or the like may be used.
[0136]
As a means for applying mechanical impact force, for example, a method using a mechanical impact type pulverizer such as a kryptron system manufactured by Kawasaki Heavy Industries, Ltd. or a turbo mill manufactured by Turbo Industry Co., a mechano-fusion system manufactured by Hosokawa Micron Co., Ltd. There is a method of applying a mechanical impact force to the toner by a force such as a compressive force or a frictional force by pressing the toner to the inside of the casing by a centrifugal force with a blade rotating at high speed, as in a device such as a hybridization system manufactured by the manufacturer.
[0137]
In the case of using the mechanical impact method, a thermomechanical impact in which the processing temperature is a temperature in the vicinity of the glass transition point Tg (Tg ± 10 ° C.) of the toner is preferable from the viewpoint of preventing aggregation and productivity. More preferably, it is particularly effective to improve the transfer efficiency to carry out at a temperature in the range of the glass transition point Tg ± 5 ° C. of the toner.
[0138]
Furthermore, the toner of the present invention is a method for obtaining a spherical toner by atomizing a molten mixture into air using a disk or a multi-fluid nozzle described in JP-B-56-13945, etc. An emulsion polymerization method typified by a dispersion polymerization method for directly producing a toner using an aqueous organic solvent in which the resulting polymer is insoluble or a soap-free polymerization method for producing a toner by directly polymerizing in the presence of a water-soluble polar polymerization initiator, etc. The toner can also be manufactured by a method of manufacturing the toner used.
[0139]
As the binder resin when the toner of the present invention is produced by a pulverization method, styrene such as polystyrene and polyvinyltoluene, and a homopolymer of a substituted product thereof; styrene-propylene copolymer, styrene-vinyltoluene copolymer, styrene -Vinylnaphthalene copolymer, styrene-methyl acrylate copolymer, styrene-ethyl acrylate copolymer, styrene-butyl acrylate copolymer, styrene-octyl acrylate copolymer, styrene-dimethylaminoethyl acrylate Copolymer, styrene-methyl methacrylate copolymer, styrene-ethyl methacrylate copolymer, styrene-butyl methacrylate copolymer, styrene-dimethylaminoethyl methacrylate copolymer, styrene-vinyl methyl ether copolymer Styrene-vinyl ethyl ether Polystyrene, styrene-vinyl methyl ketone copolymer, styrene-butadiene copolymer, styrene-isoprene copolymer, styrene-maleic acid copolymer, styrene-maleic acid ester copolymer, etc .; poly Methyl methacrylate, polybutyl methacrylate, polyvinyl acetate, polyethylene, polypropylene, polyvinyl butyral, silicone resin, polyester resin, polyamide resin, epoxy resin, polyacrylic resin, rosin, modified rosin, terpene resin, phenol resin, aliphatic or fat Cyclic hydrocarbon resins, aromatic petroleum resins, paraffin wax, carnauba wax and the like can be used alone or in combination. In particular, a styrene copolymer and a polyester resin are preferable in terms of development characteristics, fixing properties, and the like.
[0140]
In the toner of the present invention, it is also a very preferable usage form that an inorganic fine powder having an average primary particle diameter of 4 to 80 nm is added as a fluidizing agent in an amount of 0.1 to 4% by mass relative to the whole toner. Inorganic fine powder is added to improve the fluidity of the toner and to make the toner base particles evenly charged. However, the inorganic chargeable powder is treated to make it hydrophobic and adjust the toner charge amount and improve the environmental stability. It is also preferable to provide such functions.
[0141]
When the average primary particle size of the inorganic fine powder is larger than 80 nm, good toner fluidity cannot be obtained, and the toner particles are likely to be non-uniformly charged, and the triboelectric chargeability under low humidity is not uniform. Therefore, problems such as an increase in fog, a decrease in image density, and a decrease in durability cannot be avoided. When the average primary particle size of the inorganic fine powder is smaller than 4 nm, the cohesiveness between the inorganic fine particles is increased, and the aggregate is not a primary particle but an aggregate having a wide particle size distribution having a strong cohesive property that is difficult to break even by crushing treatment. It is easy to behave, and image defects due to development of the aggregate, damage to the image carrier or toner carrier, and the like are likely to occur. In order to make the charge distribution of the toner particles more uniform, the average primary particle size of the inorganic fine powder is preferably 6 to 35 nm.
[0142]
The average primary particle diameter of the inorganic fine powder is a photograph of the toner magnified by a scanning electron microscope, and is further mapped with the elements contained in the inorganic fine powder by an elemental analysis means such as XMA attached to the scanning electron microscope. The method can be measured by measuring 100 or more primary particles of inorganic fine powder present on the toner surface while adhering to or separating from the toner image, and determining the number average diameter.
[0143]
The content of the inorganic fine powder can be quantified using a calibration curve prepared from a standard sample using fluorescent X-ray analysis.
[0144]
As the inorganic fine powder added to the toner of the present invention, silica, alumina, titania and the like can be used.
[0145]
For example, as the silica, both a so-called dry method produced by vapor phase oxidation of silicon halide or dry silica called fumed silica, and so-called wet silica produced from water glass or the like can be used. There are few silanol groups on the surface and inside the silica fine powder, and Na₂O, SO₃ ^2-For example, dry silica with less production residue is preferred. In dry silica, it is also possible to obtain composite fine powders of silica and other metal oxides by using other metal halogen compounds such as aluminum chloride and titanium chloride together with silicon halogen compounds in the production process. Is also included.
[0146]
The addition amount of such inorganic fine powder having an average primary particle size of 4 to 80 nm is preferably 0.1 to 4.0 parts by mass with respect to 100 parts by mass of the toner base particles, and the addition amount is 0.1. If the amount is less than part by mass, the effect is not sufficient, and if it exceeds 4.0 parts by mass, the fixability is deteriorated.
[0147]
The inorganic fine powder is preferably hydrophobized from the viewpoint of improving characteristics in a high humidity environment. When the inorganic fine powder added to the toner absorbs moisture, the charge amount as the toner is remarkably lowered, and the developability and transferability are easily lowered.
[0148]
As treatment agents for hydrophobic treatment, treatment agents such as silicone varnish, various modified silicone varnishes, silicone oil, various modified silicone oils, silane compounds, silane coupling agents, other organic silicon compounds, and organic titanium compounds may be used alone or in combination. And may be processed.
[0149]
Among them, those treated with silicone oil are preferable, and more preferably, the inorganic fine powder treated with silicone oil at the same time as or after hydrophobizing treatment maintains a high charge amount of toner particles even in a high humidity environment. In addition, the selective developability may be reduced.
[0150]
The processing conditions for the inorganic fine powder include, for example, a silylation reaction as the first stage reaction to eliminate active hydrogen groups on the surface by chemical bonding, and then a hydrophobic thin film is formed on the surface with silicone oil as the second stage reaction. can do. As a usage-amount of a silylating agent, 5-50 mass parts is preferable with respect to 100 mass parts of inorganic fine powder. If it is less than 5 parts by mass, it is not sufficient to eliminate the active hydrogen groups on the surface of the inorganic fine particles, and if it exceeds 50 parts by mass, the siloxane compound produced by the reaction of the excess silylating agent serves as a paste to serve as the inorganic fine particles. Aggregation occurs and image defects are likely to occur.
[0151]
The silicone oil has a viscosity at 25 ° C. of 10 to 200,000 mm.²/ S, even 3,000-80,000mm²/ S is preferred. 10mm²If it is less than / s, the inorganic fine powder is not stable and the image quality tends to deteriorate due to heat and mechanical stress. 200,000mm²If it exceeds / s, uniform processing tends to be difficult.
[0152]
As a method for treating silicone oil, for example, inorganic fine powder treated with a silane compound and silicone oil may be directly mixed using a mixer such as a Henschel mixer, or a method of spraying silicone oil on inorganic fine powder. May be used. Alternatively, after dissolving or dispersing silicone oil in an appropriate solvent, inorganic fine powder may be added and mixed to remove the solvent. A method using a sprayer is more preferable in that the formation of aggregates of inorganic fine powder is relatively small.
[0153]
The treatment amount of silicone oil is 1 to 23 parts by mass, preferably 5 to 20 parts by mass with respect to 100 parts by mass of the inorganic fine powder. If the amount of the silicone oil is too small, good hydrophobicity cannot be obtained, and if it is too large, aggregation of inorganic fine particles tends to occur.
[0154]
The toner of the present invention has a primary particle size of more than 30 nm (preferably a specific surface area of 50 m) for the purpose of improving cleaning properties.²/ G), more preferably the primary particle size is 50 nm or more (preferably the specific surface area is 30 m).²It is also one of preferable modes to add inorganic or organic fine particles close to spherical shape (less than / g). For example, spherical silica particles, spherical polymethylsilsesquioxane particles, spherical resin particles and the like are preferably used.
[0155]
The developer used in the present invention may further contain other additives, for example, a lubricant powder such as a polyethylene fluoride powder, a zinc stearate powder, a polyvinylidene fluoride powder, or a cerium oxide powder within a range that does not substantially adversely affect the developer. Abrasives such as silicon carbide powder and strontium titanate powder; or fluidity-imparting agents such as titanium oxide powder and aluminum oxide powder; anti-caking agents; A small amount can also be used. These additives can also be used after hydrophobizing the surface.
[0156]
Next, an image forming method and an apparatus unit used in the present invention will be described with reference to the drawings.
[0157]
In the image forming method of the present invention, the condition of the developing process is that the toner is carried in a non-contact manner even in the so-called contact one-component development method in which the toner carrying member and the surface of the photosensitive member that is the electrostatic latent image carrying member are in contact. The non-contact one-component development method in which the toner is allowed to fly from the photosensitive member to the photosensitive member can be applied to both, and is not particularly limited.
[0158]
When the present invention is carried out by the contact one-component development method, an elastic roller is used as the toner carrier, and a method of coating the toner on the surface of the elastic roller and bringing it into contact with the surface of the photoreceptor can be used. In this case, development is performed by an electric field acting between the photosensitive member and the elastic roller facing the surface of the photosensitive member via the toner. Therefore, the surface of the elastic roller or the vicinity of the surface has a potential, and it is necessary to have an electric field in a narrow gap between the surface of the photoreceptor and the toner carrying surface. Therefore, it is possible to use a method in which the elastic rubber of the elastic roller is resistance-controlled in the middle resistance region to keep the electric field while preventing conduction with the surface of the photoreceptor, or a method of providing a thin insulating layer on the surface layer of the conductive roller. . Furthermore, a conductive resin sleeve in which the side facing the surface of the photoreceptor is covered with an insulating material on the conductive roller, or a conductive layer is provided on the side not facing the photoreceptor with the insulating sleeve is also possible. Further, it is possible to employ a configuration in which a rigid roller is used as the toner carrying member and the photosensitive member is a flexible material such as a belt. The resistance of the developing roller as the toner carrier is 10²-10⁹A range of Ω · cm is preferred.
[0159]
When the surface roughness Ra (μm) of the toner carrier is set to 0.2 to 3.0, both high image quality and high durability can be achieved. The surface roughness Ra correlates with the toner conveying ability and the toner charging ability. If the surface roughness Ra of the toner carrier exceeds 3.0, it is difficult not only to make the toner layer on the toner carrier thin, but also the chargeability of the toner is not improved, so that improvement in image quality cannot be expected. . Since the toner carrying ability on the surface of the toner carrier is suppressed by setting it to 3.0 or less, the toner layer on the toner carrier is thinned, and the number of contact between the toner carrier and the toner increases. Since the chargeability of the toner is also improved, the image quality is synergistically improved. On the other hand, when the surface roughness Ra is less than 0.2, it becomes difficult to control the toner coat amount.
[0160]
In the present invention, the surface roughness Ra of the toner carrier is measured using a surface roughness measuring device (Surfcoder SE-30H, manufactured by Kosaka Laboratory Co., Ltd.) based on JIS surface roughness “JISB0601”. Corresponds to the centerline average roughness. Specifically, a 2.5 mm portion as the measurement length a is extracted from the roughness curve in the direction of the center line, the center line of this extraction portion is the X axis, the direction of the vertical magnification is the Y axis, and the roughness curve is When expressed by y = f (x), it means a value obtained by the following formula expressed in micrometers (μm).
[0161]
[Expression 4]

[0162]
In the image forming method of the present invention, the toner carrier may be rotated in the same direction as the circumferential speed of the photosensitive member, or may be rotated in the opposite direction. When the rotation is in the same direction, it is preferable to set the peripheral speed of the toner carrier to be 1.05 to 3.0 times the peripheral speed of the photosensitive member.
[0163]
When the peripheral speed of the toner carrier is less than 1.05 times the peripheral speed of the photoreceptor, the stirring effect received by the toner on the photoreceptor is insufficient, and good image quality cannot be expected. On the other hand, when the peripheral speed ratio exceeds 3.0, toner deterioration due to mechanical stress and toner adhesion to the toner carrier are generated and promoted, which is not preferable.
[0164]
As the photoreceptor, a-Se, Cds, ZnO₂A photosensitive drum or photosensitive belt having a photoconductive insulating material layer such as OPC and a-Si is preferably used. The binder resin of the organic photosensitive layer in the OPC photoreceptor is not particularly limited.
[0165]
Of these, polycarbonate resins, polyester resins, and acrylic resins are particularly preferable because they are excellent in transferability and hardly cause toner fusion to the photoreceptor and filming of external additives.
[0166]
Next, the image forming method of the present invention will be described below with reference to the accompanying drawings.
[0167]
In FIG. 1, 100 is a developing device, 109 is a photosensitive member, 105 is a transfer target such as paper, 106 is a transfer member, 107 is a fixing pressure roller, 108 is a fixing heating roller, and 110 is in contact with the photosensitive member 109. A primary charging member that performs direct charging is shown.
[0168]
A bias power source 115 is connected to the primary charging member 110 so as to uniformly charge the surface of the photoconductor 109.
[0169]
The developing device 100 contains toner 104 and includes a toner carrier 102 that contacts the photoconductor 109 and rotates in the direction of the arrow. Further, a developing blade 101 for regulating the amount of toner and applying a charge, and a coating roller that rotates in the direction of the arrow in order to attach the toner 104 to the toner carrier 102 and to apply a charge to the toner by friction with the toner carrier 102 103 is also provided. A developing bias power source 117 is connected to the toner carrier 102. A bias power source (not shown) is also connected to the application roller 103, and when negatively charged toner is used, the voltage is more negative than the developing bias, and when positively charged toner is used, the voltage is more positive than the developing bias. Is set.
[0170]
A transfer bias power supply 116 having a polarity opposite to that of the photoconductor 109 is connected to the transfer member 106.
[0171]
Here, the length in the rotational direction at the contact portion between the photosensitive member 109 and the toner carrier 102, that is, the so-called development nip width is preferably 0.2 mm or more and 8.0 mm or less. If the thickness is less than 0.2 mm, the development amount is insufficient and a satisfactory image density cannot be obtained, and the transfer residual toner is not sufficiently collected. If it exceeds 8.0 mm, the amount of toner supplied becomes excessive, fog suppression is likely to deteriorate, and the wear of the photoreceptor is also adversely affected.
[0172]
As the toner carrier, a so-called elastic roller having an elastic layer on the surface is preferably used.
[0173]
The hardness of the material of the elastic layer used is preferably 30 to 60 degrees (asker-C / load 1 kg).
[0174]
The resistance of the toner carrier is 10 in terms of volume resistance.²-10⁹A range of about Ωcm is preferable. 10²If it is lower than Ωcm, for example, if there is a pinhole on the surface of the photoconductor 109, an overcurrent may flow. Conversely, 10⁹If it is higher than Ωcm, the toner is likely to be charged up due to frictional charging, and the image density is likely to decrease.
[0175]
The toner coat amount on the toner carrier is 0.1 to 1.5 mg / cm.²Is preferred. 0.1 mg / cm²If it is less than 1, it is difficult to obtain a sufficient image density, and 1.5 mg / cm²If it exceeds the upper limit, it becomes difficult to uniformly triboelectrically charge all the individual toner particles, which causes deterioration of fog suppression. Furthermore, 0.2 to 0.9 mg / cm²Is more preferable.
[0176]
The toner coating amount is controlled by the developing blade 101, and the developing blade 101 is in contact with the toner carrier 102 through the toner layer. The contact pressure at this time is preferably in the range of 4.9 to 49 N / m (5 to 50 gf / cm). If it is less than 4.9 N / m, it is difficult to control the toner coating amount and uniform triboelectric charging, leading to deterioration of fog suppression. On the other hand, if it exceeds 49 N / m, the toner particles are subjected to an excessive load, so that the deformation of the particles and the fusion of the toner to the developing blade or the toner carrier are likely to occur.
[0177]
The free end portion of the restricting member may have any shape as long as a preferable NE length is provided. For example, in addition to a linear cross-sectional shape, an L-shape bent near the tip, or near the tip A shape having a spherical shape is preferably used.
[0178]
As the toner coat amount regulating member, a rigid metal blade or the like may be used in addition to the elastic blade for press-fitting toner.
[0179]
For the elastic regulating member, it is preferable to select a frictional charging material suitable for charging the toner to a desired polarity. A rubber elastic body such as silicone rubber, urethane rubber or NBR, or a synthetic resin such as polyethylene terephthalate. A metal elastic body such as an elastic body, stainless steel, steel, or phosphor bronze can be used. Moreover, those composites may be sufficient.
[0180]
Further, when durability is required for the elastic regulating member and the toner carrying member, it is preferable that the metal elastic member is bonded or coated with a resin or rubber so as to contact the sleeve contact portion.
[0181]
Furthermore, an organic substance or an inorganic substance may be added to the elastic regulating member, and it may be melt-mixed or dispersed. For example, the chargeability of the toner can be controlled by adding a metal oxide, metal powder, ceramics, carbon allotrope, whisker, inorganic fiber, dye, pigment, surfactant or the like. In particular, when the elastic body is a molded body such as rubber or resin, fine metal oxide powders such as silica, alumina, titania, tin oxide, zirconia, and zinc oxide, carbon black, and a charge control agent generally used for toners Etc. are also preferably contained.
[0182]
Furthermore, application of a DC electric field and / or an AC electric field to the regulating member also improves the uniform thin-layer coating property and uniform charging property due to the loosening action on the toner, achieving a sufficient image density and high quality. Images can be obtained.
[0183]
In FIG. 1, a primary charging member 110 uniformly charges a photoconductor 109 that rotates in the direction of an arrow.
[0184]
The primary charging member used here is a charging roller having a basic configuration of a central core metal 110b and a conductive elastic layer 110a formed on the outer periphery thereof. The charging roller 110 is brought into contact with the entire surface of the electrostatic latent image carrier with a pressing force, and is rotated following the rotation of the electrostatic latent image carrier 109.
[0185]
As a preferable process condition when using a charging roller, the contact pressure of the roller is 4.9 to 490 N / m (5 to 500 gf / cm), and an applied voltage is a DC voltage or an AC voltage superimposed on a DC voltage. In the present invention, an applied voltage of only a DC voltage is preferably used, and a voltage value in this case is used in a range of ± 0.2 to ± 5 kV.
[0186]
Other charging means include a method using a charging blade and a method using a conductive brush. These contact charging means have an effect that a high voltage is unnecessary and generation of ozone is reduced as compared with non-contact corona charging. The material of the charging roller and charging blade as the contact charging means is preferably conductive rubber, and a release coating may be provided on the surface thereof. As the releasable coating, nylon resin, PVDF (polyvinylidene fluoride), PVDC (polyvinylidene chloride), and the like are applicable.
[0187]
Following the primary charging step, an electrostatic latent image corresponding to the information signal is formed on the photoconductor 109 by exposure 123 from the light emitting element, and the electrostatic latent image can be developed with toner at a position where it abuts the toner carrier 102. Visualize. Furthermore, in the image forming method of the present invention, particularly in combination with a developing system in which a digital latent image is formed on a photoreceptor, it becomes possible to develop the dot latent image faithfully without disturbing the latent image. . The visible image is transferred to the transfer target 105 by the transfer member 106 and passes between the heating roller 108 and the pressure roller 107 to be fixed to obtain a permanent image. In addition to the heat roller system, the heating and pressure fixing means includes a heating roller having a built-in heating element such as a halogen heater and an elastic pressure roller pressed against the heating roller with a pressing force. A system in which heat is fixed by a heater through a film is also used.
[0188]
On the other hand, the untransferred toner remaining on the photoconductor 109 without being transferred is collected by a cleaner 138 having a cleaning blade in contact with the surface of the photoconductor 109, and the photoconductor 109 is cleaned.
[0189]
Next, the surface potential of the toner coat layer on the toner carrier, which is a feature of the present invention and is essential for achieving the occurrence of fogging and density stabilization, will be described.
[0190]
In the image forming method of the present invention, the surface potential of the toner coat layer on the toner carrier is such that the surface potential at the start of rotation of the toner carrier is 10 seconds to -5V. .
[0191]
A more preferable range is −7 to −45V, and still more preferably −10 to −40V.
[0192]
If the surface potential at 10 seconds after the start of rotation is less than −5V, a developable toner layer is not sufficiently formed on the toner carrying member, and a wait time is inevitably required until the density is stabilized. Inappropriate for the system. Even if the toner is stabilized at a value of -5 V or less, the fog is poor due to insufficient charging potential of the toner.
[0193]
On the other hand, if the voltage exceeds -50V, the charged potential is excessive, and the electrostatic repulsion between the overcharged toners on the toner carrier causes the uniformity of the charge distribution on the coat surface. The uniformity becomes worse.
[0194]
In the image forming method of the present invention, a sufficient maximum density is expected when the surface potential at 10 seconds is -5 V or more, but the saturated charging potential at 1 minute at the start of rotation is preferably -10 V to -50 V, more preferably -12 V. By satisfying -40V, stable halftone uniformity and high-quality images with less fog can be promised.
[0195]
The surface potential was measured by setting a developing device of a cartridge EP-85 (manufactured by Canon) of a commercially available laser beam printer LBP-2510 (manufactured by Canon) to an idle rotating machine and a peripheral speed of 180 mm / sec. The value at the time of 10 seconds when rotating at -10 was used. Specifically, 200 g of toner is charged, left overnight under normal temperature and humidity conditions (temperature 23 ° C., humidity 50% RH), the probe is opposed to the toner carrier with a 1 mm gap, and a surface potential meter model 344 ( The rise of the charging potential was measured using a Trek company).
[0196]
An example of the rise of the potential read by Memory HiCorder (manufactured by Hioki Electric Co., Ltd.) is shown in FIG. 2 (profile when idling for 90 seconds at a peripheral speed of 180 mm / sec.).
[0197]
Next, an image forming method and an apparatus unit using the toner of the present invention will be described with reference to the drawings.
[0198]
3 and 4 are schematic views of an image forming apparatus that collectively transfers multiple toner images onto a recording material using an intermediate transfer member in the image forming method of the present invention.
[0199]
FIG. 3 is a schematic view of an image forming apparatus that batch-transfers multiple toner images onto a recording material using an intermediate transfer drum in the image forming method of the present invention.
[0200]
The surface of the photosensitive drum 1 as a latent image carrier is brought into contact with a rotatable charging roller 2 to which a charging bias voltage as a charging member is applied while rotating to uniformly primary-charge the surface of the photosensitive drum, A first electrostatic latent image is formed on the photosensitive drum 1 by a laser beam E emitted from a light source device L as an exposure unit. The formed first electrostatic latent image is developed with the black toner in the black developing device 4Bk as a first developing device provided in the rotatable rotary unit 10 to form a black toner image. The black toner image formed on the photosensitive drum 1 is electrostatically primary transferred onto the intermediate transfer drum 5 by the action of the transfer bias voltage applied to the conductive support of the intermediate transfer drum. Next, a second electrostatic latent image is formed on the surface of the photosensitive drum 1 in the same manner as described above, and the rotary unit 10 is rotated so that the yellow toner in the yellow developing device 4Y as the second developing device is used. Development is performed to form a yellow toner image, and the yellow toner image is electrostatically primary transferred onto the intermediate transfer drum 5 on which the black toner image is primarily transferred. Similarly, the third electrostatic latent image and the fourth electrostatic latent image are rotated as the magenta toner and the fourth developing unit in the magenta developing unit 4M as the third developing unit by rotating the rotary unit 10. Development and primary transfer are sequentially performed with the cyan toner in the cyan developing device 4C, and the toner images of the respective colors are primarily transferred onto the intermediate transfer drum 5. The multiple toner image primarily transferred onto the intermediate transfer drum 5 is electrostatically applied onto the recording material P by the action of the transfer bias voltage from the second transfer device 8 positioned on the opposite side via the recording material P. Secondary transfer is performed at once. The multiple toner image secondarily transferred onto the recording material P is heat-fixed on the recording material P by a fixing device 9 having a heating roller and a pressure roller. The transfer residual toner remaining on the surface of the photosensitive drum 1 after the transfer is collected by a cleaner having a cleaning blade in contact with the surface of the photosensitive drum 1, and the photosensitive drum 1 is cleaned.
[0201]
In the primary transfer from the photosensitive drum 1 to the intermediate transfer drum 5, a transfer current is obtained by applying a bias from a power source (not shown) to the conductive support of the intermediate transfer drum 5 as the first transfer device. The image is transferred.
[0202]
The intermediate transfer drum 5 includes a conductive support 5a that is a rigid body and an elastic layer 5b that covers the surface.
[0203]
As the conductive support 5a, a metal or an alloy such as aluminum, iron, copper, and stainless steel, and a conductive resin in which carbon or metal particles are dispersed can be used. The thing which penetrated the axis | shaft in the center, the thing which gave the inside of a cylinder reinforcement, etc. are mentioned.
[0204]
The elastic layer 5b is not particularly limited, but styrene-butadiene rubber, high styrene rubber, butadiene rubber, isoprene rubber, ethylene-propylene copolymer, nitrile butadiene rubber (NBR), chloroprene rubber, butyl rubber, silicone. Elastomer rubbers such as rubber, fluorine rubber, nitrile rubber, urethane rubber, acrylic rubber, epichlorohydrin rubber and norbornene rubber are preferably used. A resin such as a polyolefin resin, a silicone resin, a fluorine resin, or a polycarbonate, and a copolymer or a mixture thereof may be used.
[0205]
Further, a surface layer in which lubricant powder having high lubricity and water repellency is dispersed in an arbitrary binder may be provided on the surface of the elastic layer.
[0206]
The lubricant is not particularly limited, but various fluororubbers, fluoroelastomers, fluorocarbons and polytetrafluoroethylene (PTFE), polyvinylidene fluoride (PVDF), ethylene-tetrafluoroethylene copolymers in which fluorine is bonded to graphite or graphite. (ETFE) and fluorine compounds such as tetrafluoroethylene-perfluoroalkyl vinyl ether copolymer (PFA), silicone compounds such as silicone resin particles, silicone rubber and silicone elastomer, polyethylene (PE), polypropylene (PP), polystyrene ( PS), acrylic resin, polyamide resin, phenol resin, epoxy resin and the like are preferably used.
[0207]
In addition, a conductive agent may be added to the surface layer binder in order to control resistance. Examples of the conductive agent include various conductive inorganic particles and carbon black, an ionic conductive agent, a conductive resin, and a conductive particle-dispersed resin.
[0208]
The multiple toner images on the intermediate transfer drum 5 are secondarily transferred onto the recording material P all at once by the second transfer device 8, and the transfer means 8 is a non-contact electrostatic transfer means or a transfer roller using a corona charger. In addition, contact electrostatic transfer means using a transfer belt can be used.
[0209]
The fixing device 9 is replaced with a heat roller fixing device having a heating roller 9a and a pressure roller 9b, and the toner image on the recording material P is heated by heating a film in contact with the toner image on the recording material P. Also, a film heat fixing device that heat-fixes a multiple toner image on the recording material P can be used.
[0210]
Instead of the intermediate transfer drum as the intermediate transfer member used in the image forming apparatus shown in FIG. 3, it is also possible to batch transfer the multiple toner images onto the recording material using an intermediate transfer belt. The configuration of the intermediate transfer belt is shown in FIG.
[0211]
The toner image formed and carried on the photosensitive drum 1 is formed by the primary transfer bias applied from the primary transfer roller 42 to the intermediate transfer belt 40 in the process of passing through the nip portion between the photosensitive drum 1 and the intermediate transfer belt 40. Due to the applied electric field, primary transfer is sequentially performed on the outer peripheral surface of the intermediate transfer belt 40.
[0212]
A primary transfer bias for sequentially superimposing and transferring the first to fourth color toner images from the photosensitive drum 1 to the intermediate transfer belt 40 is applied from a bias power supply 44 with a polarity opposite to that of the toner.
[0213]
In the primary transfer process of the first to third color toner images from the photosensitive drum 1 to the intermediate transfer belt 40, the secondary transfer roller 43 b and the intermediate transfer belt cleaner 49 can be separated from the intermediate transfer belt 40.
[0214]
Reference numeral 43b denotes a secondary transfer roller, which is supported in parallel with the secondary transfer counter roller 43a so as to be separated from the lower surface portion of the intermediate transfer belt 40.
[0215]
When the composite color toner image transferred onto the intermediate transfer belt 40 is transferred to the transfer material P, the secondary transfer roller 43b is brought into contact with the intermediate transfer belt 40, and the intermediate transfer belt 40 and the secondary transfer roller 43b. The transfer material P is fed to the contact nip at a predetermined timing, and a secondary transfer bias is applied from the bias power source 46 to the secondary transfer roller 43b. The composite color toner image is secondarily transferred from the intermediate transfer belt 40 to the transfer material P by the secondary transfer bias.
[0216]
After the image transfer to the transfer material P is completed, a cleaning charging member 49 is brought into contact with the intermediate transfer belt 40, and a bias having a polarity opposite to that of the photosensitive drum 1 is applied from the bias power supply 45 to transfer the image to the transfer material P. Instead, a charge having a polarity opposite to that of the photosensitive drum 1 is applied to the toner (transfer residual toner) remaining on the intermediate transfer belt 40.
[0217]
The transfer residual toner is electrostatically transferred to the photosensitive drum 1 at and near the nip portion with the photosensitive drum 1 to clean the intermediate transfer member.
[0218]
The intermediate transfer belt includes a belt-shaped base layer and a surface treatment layer provided on the base layer. The surface treatment layer may be composed of a plurality of layers.
[0219]
Rubber, elastomer, or resin can be used for the base layer and the surface treatment layer. For example, as rubber and elastomer, natural rubber, isoprene rubber, styrene-butadiene rubber, butadiene rubber, butyl rubber, ethylene-propylene rubber, ethylene-propylene terpolymer, chloroprene rubber, chlorosulfonated polyethylene, chlorinated polyethylene, acrylonitrile butadiene rubber, Urethane rubber, syndiotactic 1,2-polybutadiene, epichlorohydrin rubber, acrylic rubber, silicone rubber, fluorine rubber, polysulfurized rubber, polynorbornene rubber, hydrogenated nitrile rubber and thermoplastic elastomer (for example, polystyrene, polyolefin, 1 type or 2 types or more selected from the group consisting of polyvinyl chloride, polyurethane, polyamide, polyester, fluororesin, etc. can be used.However, it is not limited to the said material. As the resin, a resin such as a polyolefin resin, a silicone resin, a fluorine resin, or a polycarbonate can be used. A copolymer or a mixture of these resins may be used.
[0220]
As the base layer, the rubber, elastomer and resin described above can be used in the form of a film. In addition, a material obtained by coating, dipping, or spraying the above-described rubber, elastomer, or resin on one side or both sides of a core layer in the form of a woven fabric, a nonwoven fabric, a thread, or a film may be used.
[0221]
The material constituting the core layer is, for example, natural fibers such as cotton, silk, hemp and wool; regenerated fibers such as chitin fiber, alginic acid fiber and regenerated cellulose fiber; semisynthetic fibers such as acetate fiber; polyester fiber, nylon fiber, Synthetic fibers such as acrylic fiber, polyolefin fiber, polyvinyl alcohol fiber, polyvinyl chloride fiber, polyvinylidene chloride fiber, polyurethane fiber, polyalkyl paraoxybenzoate fiber, polyacetal fiber, aramid fiber, polyfluoroethylene fiber and phenol fiber; carbon fiber, One or more selected from the group consisting of inorganic fibers such as glass fibers and boron fibers; metal fibers such as iron fibers and copper fibers can be used. Of course, the material is not limited to the above.
[0222]
Further, a conductive agent may be added to the base layer and the surface treatment layer in order to adjust the resistance value of the intermediate transfer member. Although it does not specifically limit as a electrically conductive agent, For example, metal powder, such as carbon, aluminum, and nickel, metal oxides, such as a titanium oxide, and quaternary ammonium salt containing polymethyl methacrylate, polyvinyl aniline, polyvinyl pyrrole, One kind or two or more kinds selected from the group consisting of polydiacetylene, polyethyleneimine, boron-containing polymer compounds, conductive polymer compounds such as polypyrrole, and the like can be used. However, it is not limited to the said electrically conductive agent.
[0223]
Further, a lubricant may be added as necessary in order to increase the slipperiness of the surface of the intermediate transfer member and improve the transferability.
[0224]
The lubricant is not particularly limited, but various fluororubbers, fluoroelastomers, fluorocarbons and polytetrafluoroethylene (PTFE), polyvinylidene fluoride (PVDF), ethylene-tetrafluoroethylene copolymers in which fluorine is bonded to graphite or graphite. (ETFE) and fluorine compounds such as tetrafluoroethylene-perfluoroalkyl vinyl ether copolymer (PFA), silicone compounds such as silicone resin, silicone rubber and silicone elastomer, polyethylene (PE), polypropylene (PP), polystyrene (PS ), Acrylic resin, polyamide resin, phenol resin, epoxy resin and the like are preferably used.
[0225]
Next, an image forming method will be described with reference to FIG. 5 in which toner images of respective colors are formed in a plurality of image forming units and transferred onto the same transfer material in sequence.
[0226]
Here, first, second, third and fourth image forming units 29a, 29b, 29c and 29d are arranged in parallel, and each image forming unit is a dedicated electrostatic latent image holding member, a so-called photosensitive drum. 19a, 19b, 19c and 19d.
[0227]
The photosensitive drums 19a to 19d have latent image forming means 23a, 23b, 23c and 23d, developing units 17a, 17b, 17c and 17d, transfer discharge units 24a, 24b, 24c and 24d, and cleaning units 18a and 18b on the outer peripheral side thereof. , 18c and 18d are arranged.
[0228]
With such a configuration, first, a latent image of, for example, a yellow component color in the original image is formed on the photosensitive drum 19a of the first image forming unit 29a by the latent image forming unit 23a. The latent image is converted into a visible image by the developer having yellow toner of the developing unit 17a, and transferred to the recording material S as a transfer material by the transfer unit 24a.
[0229]
As described above, while the yellow image is transferred to the transfer material S, the second image forming unit 29b forms a magenta component color latent image on the photosensitive drum 19b, and subsequently has the magenta toner of the developing unit 17b. A visible image is formed with the developer. This visible image (magenta toner image) is transferred to a predetermined position of the transfer material S when the transfer material S, which has been transferred by the first image forming unit 29a, is transferred to the transfer unit 24b. The
[0230]
Thereafter, cyan and black images are formed by the third and fourth image forming portions 29c and 29d in the same manner as described above, and the cyan and black colors are transferred onto the same transfer material S. To do. When such an image forming process is completed, the transfer material S is conveyed to the fixing unit 22 and the image on the transfer material S is fixed. As a result, a multicolor image is obtained on the transfer material S. The photosensitive drums 19a, 19b, 19c, and 19d after the transfer are removed from the residual toner by the cleaning units 18a, 18b, 18c, and 18d, and are used for subsequent latent image formation.
[0231]
In the image forming apparatus, a conveyance belt 25 is used to convey the recording material S as a transfer material. In FIG. 5, the transfer material S is conveyed from the right side to the left side. Each image forming section 29a, 29b, 29c and 29d passes through each transfer section 24a, 24b, 24c and 24d and undergoes transfer.
[0232]
In this image forming method, a transport belt using a mesh of Tetoron (registered trademark) fiber as a transport means for transporting a transfer material and a polyethylene terephthalate resin, a polyimide resin, and a urethane resin from the viewpoint of durability. A conveyor belt using such a thin dielectric sheet is used.
[0233]
When the transfer material S passes through the fourth image forming portion 29d, an AC voltage is applied to the static eliminator 20, the transfer material S is neutralized and separated from the belt 25, and then enters the fixing device 22 where the image is fixed and discharged. It is discharged from the outlet 26.
[0234]
In this image forming method, each of the image forming portions is provided with an independent electrostatic latent image holding member, and the transfer material is a belt-type conveying unit, and the transfer portion of each electrostatic latent image holding member is sequentially transferred. You may comprise so that it may be sent to.
[0235]
In this image forming method, an electrostatic latent image holding member common to the image forming unit is provided, and the transfer material is repeatedly sent to the transfer unit of the electrostatic latent image holding member by a drum-type conveying unit. In other words, each color may be transferred.
[0236]
However, since the conveyance belt has a high volume resistance, the conveyance belt increases the charge amount in the process of repeating the transfer several times as in the color image forming apparatus. For this reason, uniform transfer cannot be maintained unless the transfer current is sequentially increased for each transfer.
[0237]
Since the toner of the present invention has excellent transferability, even if the charge of the conveying means increases every time the transfer is repeated, the transferability of the toner in each transfer can be made uniform with the same transfer current, and a high-quality high-quality image can be obtained. It will be.
[0238]
FIG. 6 shows an image formation using a transfer belt as a secondary transfer means when a color toner image of four colors transferred onto the intermediate transfer drum using the intermediate transfer drum is secondarily transferred collectively to a recording material. It is explanatory drawing of an apparatus.
[0239]
In the apparatus system shown in FIG. 6, the developers 244-1, 244-2, 244-3, and 244-4 are respectively provided with a developer having cyan toner, a developer having magenta toner, a developer having yellow toner, and a black toner. A developer having toner is introduced to develop the electrostatic image formed on the photoreceptor 241, and each color toner image is formed on the photoreceptor 241. The photoreceptor 241 is a-Se, Cds, ZnO.₂, OPC, a photosensitive drum or photosensitive belt having a photoconductive insulating material layer such as a-Si. The photoreceptor 241 is rotated in the direction of the arrow by a driving device (not shown).
[0240]
As the photoreceptor 241, an amorphous silicon photosensitive layer or a photoreceptor having an organic photosensitive layer is preferably used.
[0241]
The organic photosensitive layer may be a single layer type in which the photosensitive layer contains a charge generation material and a substance having charge transport performance in the same layer, or a function-separated type photosensitive layer having the charge generation layer as a component. It may be. A laminated photosensitive layer having a structure in which a charge generation layer and then a charge transport layer are laminated in this order on a conductive substrate is one preferred example.
[0242]
The binder resin for the organic photosensitive layer is particularly a polycarbonate resin, a polyester resin, or an acrylic resin, and has good transferability and cleaning properties, and poor cleaning, toner fusion to the photoreceptor, and filming of external additives are unlikely to occur.
[0243]
In the charging process, there are a non-contact method using a corona charger 241 and a contact type method using a roller or the like. For efficient uniform charging, simplification, and low ozone generation, a contact type as shown in FIG. 6 is preferably used.
[0244]
The charging roller 242 has a basic configuration of a central cored bar 242b and a conductive elastic layer 242a that forms the outer periphery thereof. The charging roller 242 is pressed against the surface of the photoconductor 241 with a pressing force, and is driven to rotate as the photoconductor 241 rotates.
[0245]
As a preferable process condition when using a charging roller, the contact pressure of the roller is 4.9 to 490 N / m (5 to 500 gf / cm), and when a DC voltage is superimposed on an AC voltage, an AC current is used. Voltage = 0.5-5 kVpp, AC frequency = 50 Hz-5 kHz, DC voltage = ± 0.2- ± 1.5 kV, and DC voltage = ± 0.2- ± 5 kV when DC voltage is used.
[0246]
Other charging means include a method using a charging blade and a method using a conductive brush. These contact charging means are effective in that a high voltage is unnecessary and generation of ozone is reduced.
[0247]
The material of the charging roller and charging blade as the contact charging means is preferably conductive rubber, and a release coating may be provided on the surface thereof. As the releasable coating, nylon resin, PVDF (polyvinylidene fluoride), PVDC (polyvinylidene chloride), and the like are applicable.
[0248]
The toner image on the photoreceptor is transferred to an intermediate transfer drum 245 to which a voltage (for example, ± 0.1 to ± 5 kV) is applied. The surface of the photoreceptor after the transfer is cleaned by a cleaning unit 249 having a cleaning blade 248.
[0249]
The intermediate transfer drum 245 includes a pipe-shaped conductive metal core 245b and a medium-resistance elastic layer 245a formed on the outer peripheral surface thereof. The cored bar 245b may be a plastic pipe with conductive plating.
[0250]
The medium resistance elastic layer 245a is made of elastic material such as silicone rubber, Teflon (registered trademark) rubber, chloroprene rubber, urethane rubber, EPDM (ethylene propylene diene terpolymer), carbon black, zinc oxide, oxidized Mixing and dispersing a conductivity-imparting material such as tin or silicon carbide to give an electric resistance value (volume resistivity) of 10⁵-10¹¹Solid or foamed layer adjusted to medium resistance of Ω · cm.
[0251]
The intermediate transfer drum 245 is disposed in parallel with the photoconductor 241 and is in contact with the lower surface of the photoconductor 241, and rotates in the counterclockwise direction indicated by an arrow at the same peripheral speed as the photoconductor 241.
[0252]
The first color toner image formed and supported on the surface of the photosensitive member 241 passes through the transfer nip where the photosensitive member 241 and the intermediate transfer drum 245 are in contact with each other, and is applied to the transfer nip region by the transfer bias applied to the intermediate transfer drum 245. The intermediate transfer is sequentially performed on the outer surface of the intermediate transfer drum 245 by the formed electric field.
[0253]
If necessary, the surface of the intermediate transfer drum 245 is cleaned by a removable cleaning unit 280 after the toner image is transferred onto the transfer material. When there is a toner image on the intermediate transfer drum, the cleaning means 280 is separated from the surface of the intermediate transfer member so as not to disturb the toner image.
[0254]
A transfer unit is disposed in parallel with the intermediate transfer drum 245 and brought into contact with the lower surface of the intermediate transfer drum 245. The transfer unit 247 is, for example, a transfer roller or a transfer belt, and has the same peripheral speed as the intermediate transfer drum. To rotate clockwise. The transfer unit may be disposed so as to directly contact the intermediate transfer drum, or a belt or the like may be disposed between the intermediate transfer drum and the transfer unit.
[0255]
In the case of the transfer roller, the basic configuration is a central core metal and a conductive elastic layer formed on the outer periphery thereof.
[0256]
Common materials can be used as the intermediate transfer drum and the transfer roller. By setting the volume resistivity of the elastic layer of the transfer roller smaller than the volume resistivity of the elastic layer of the intermediate transfer drum, the applied voltage to the transfer roller can be reduced and a good toner image is formed on the transfer material In addition, it is possible to prevent the transfer material from being wound around the intermediate transfer member. In particular, the volume specific resistance value of the elastic layer of the intermediate transfer member is particularly preferably 10 times or more than the volume specific resistance value of the elastic layer of the transfer roller.
[0257]
The hardness of the intermediate transfer drum and the transfer roller is measured according to JIS K-6301. The intermediate transfer drum used in the present invention is preferably composed of an elastic layer belonging to a range of 10 to 40 degrees, while the hardness of the elastic layer of the transfer roller is harder than the hardness of the elastic layer of the intermediate transfer drum. Those having a value of ˜80 degrees are preferable for preventing the transfer material from being wound around the intermediate transfer drum. When the hardness of the intermediate transfer drum and that of the transfer roller are reversed, a recess is formed on the transfer roller side, and the transfer material is easily wound around the intermediate transfer drum.
[0258]
In FIG. 6, a transfer belt 247 is disposed below the intermediate transfer drum 245. The transfer belt 247 is stretched between two rollers arranged in parallel to the axis of the intermediate transfer drum 245, that is, a bias roller 247a and a tension roller 247c, and is driven by a driving unit (not shown). Since the transfer belt 247 is configured such that the bias roller 247a side can move in the arrow direction around the tension roller 247c side, the transfer belt 247 can contact and separate from the intermediate transfer drum 245 in the arrow direction from below. A desired secondary transfer bias is applied to the bias roller 247a by a secondary transfer bias source 247d, while the tension roller 247c is grounded.
[0259]
Next, regarding the transfer belt 247, in this embodiment, carbon is dispersed in a thermosetting urethane elastomer to have a thickness of about 300 μm and a volume resistivity of 10⁸-10¹²In addition to being controlled to Ω · cm (when 1 kV is applied), fluororubber 20 μm, volume resistivity 10¹⁵A rubber belt controlled to Ω · cm (when 1 kV was applied) was used. The outer diameter is a tube shape with a circumference of 80 × width of 300 mm.
[0260]
The transfer belt 247 is applied with a tension that extends about 5% by the bias roller 247a and the tension roller 247c.
[0261]
The transfer means 247 is rotated with a difference in speed or peripheral speed from the intermediate transfer drum 245. The transfer material 246 is conveyed between the intermediate transfer drum 245 and the transfer unit 247, and at the same time, a bias having a polarity opposite to the frictional charge of the toner is applied to the transfer unit 247 from the secondary transfer bias source 247d. The toner image on the transfer drum 245 is transferred to the surface side of the transfer material 246.
[0262]
As the material of the transfer rotator, the same material as that of the charging roller can be used. As a preferable transfer process condition, the roller contact pressure is 4.9 to 490 N / m (5 to 500 gf / cm). The DC voltage is ± 0.2 to ± 10 kV.
[0263]
For example, the conductive elastic layer 247a1 of the bias roller 247a has a volume resistance 10 such as polyurethane, ethylene-propylene-diene terpolymer (EPDM) in which a conductive material such as carbon is dispersed.⁶-10¹⁰It is made of an elastic body of about Ωcm. A bias is applied to the cored bar 247a2 by a constant voltage power source. The bias condition is preferably ± 0.2 to ± 10 kV.
[0264]
Next, the transfer material 246 is conveyed to a fixing device 281 having a heating roller incorporating a heating element such as a halogen heater and an elastic pressure roller pressed against it with a pressing force. By passing between the pressure rollers, the toner image is fixed to the transfer material by heating and pressing. A method of fixing with a heater through a film may be used.
[0265]
【Example】
Hereinafter, the present invention will be specifically described with reference to production examples and examples, but this does not limit the present invention in any way. In addition, all the parts in the following mixing | blending are mass parts.
[0266]
(Production example of polar polymer 1)
In a pressurizable reaction vessel equipped with a reflux tube, a stirrer, a thermometer, a nitrogen introduction tube, a dropping device and a decompression device, 250 parts of methanol as a solvent, 150 parts of 2-butanone and 100 parts of 2-propanol, styrene as a monomer 82 parts, 10 parts of 2-ethylhexyl acrylate, and 8 parts of 2-acrylamido-2-methylpropanesulfonic acid were added and heated to reflux temperature with stirring. A solution obtained by diluting 1 part of t-butylperoxy-2-ethylhexanoate as a polymerization initiator with 20 parts of 2-butanone was added dropwise over 30 minutes, and stirring was continued for 5 hours. Further, t-butylperoxy-2 was further added. -A solution obtained by diluting 1 part of ethylhexanoate with 20 parts of 2-butanone was added dropwise over 30 minutes, and the mixture was further stirred for 5 hours to complete the polymerization. Further, 500 parts of deionized water was added while maintaining the temperature, and after stirring for 2 hours at 80 to 100 revolutions per minute so as not to disturb the interface between the organic layer and the aqueous layer, the mixture was allowed to stand for 30 minutes and separated. The aqueous layer was discarded, and anhydrous sodium sulfate was added to the organic layer for dehydration.
[0267]
Next, the polymer obtained after the polymerization solvent was distilled off under reduced pressure was coarsely pulverized to 100 μm or less using a cutter mill equipped with a 150 mesh screen. The obtained polar polymer had a Tg of about 75 ° C. The obtained polar polymer is designated as polar polymer 1.
[0268]
(Production example of polar polymers 2 to 5)
In Polar Polymer Production Example 1, polar polymers 2 to 5 were produced in the same manner except that the types and amounts of monomers used were changed to those shown in Table 1.
[0269]
[Table 1]

[0270]
<Example 1>
To 400 parts of ion exchange water, 0.1M Na₃PO₄After 450 parts of the aqueous solution was added and heated to 50 ° C., the mixture was stirred at 10,000 rpm using a TK homomixer (manufactured by Tokushu Kika Kogyo). To this, 1.0M-CaCl₂68 parts of an aqueous solution was added to obtain an aqueous medium containing a calcium phosphate salt.
[0271]
on the other hand,
81 parts of styrene
19 parts of n-butyl acrylate
C. I. Pigment Blue 15: 3 5 parts
1 part of polar polymer 1
0.5 part of an aluminum complex of 3,5-di-t-butylsalicylic acid
10 parts of saturated polyester
(Acid value 10 mgKOH / g, peak molecular weight 11,000)
Ester wax (endothermic peak = 70 ° C) 12 parts
0.2 parts of divinylbenzene
The above formulation was heated to 60 ° C., and uniformly dissolved and dispersed at 6000 rpm using a TK homomixer (manufactured by Tokushu Kika Kogyo). In this, 3.5 parts of polymerization initiators 2,2'-azobis (2,4-dimethylvaleronitrile) were dissolved to prepare a polymerizable monomer composition.
[0272]
The polymerizable monomer composition is charged into the aqueous medium, 60 ° C., N₂Under an atmosphere, the polymerizable monomer composition was granulated by stirring at 12,000 rpm with a TK homomixer.
[0273]
Thereafter, while stirring with a paddle stirring blade, the temperature was raised to 80 ° C. at a rate of temperature increase of 40 ° C./Hr after 5 hours and reacted for 5 hours. After completion of the polymerization reaction, the residual monomer was distilled off under reduced pressure. After cooling, hydrochloric acid was added, and the mixture was stirred for 6 hours to dissolve the calcium phosphate salt.
[0274]
Thereafter, filtration, washing with ion exchange water, and drying were performed to obtain toner particles (1).
[0275]
Hydrophobic silica fine powder (BET: 180 m) treated with hexamethyldisilazane and then with silicone oil as a flow improver for 100 parts of the toner particles.²/ G) Toner (1) of the present invention was obtained by dry-mixing 1.5 parts with a Henschel mixer (Mitsui Mining Co., Ltd.) for 5 minutes.
[0276]
When the weight average particle diameter and average circularity of toner (1) were calculated using a flow type particle image measuring apparatus manufactured by Toa Medical Electronics Co., Ltd., they were 6.6 μm and 0.985, respectively.
[0277]
Table 2 shows the physical property values of the toner.
[0278]
The toner (1) is a non-magnetic one-component developer (1), and the developer is used in an image forming apparatus as shown in FIG. 7, under high temperature and high humidity conditions (temperature 30 ° C., humidity 80% RH), normal temperature. Image evaluation was performed under normal humidity conditions (temperature 23 ° C., humidity 50% RH) and low temperature low humidity conditions (temperature 15 ° C., humidity 10% RH). The image forming apparatus will be described below.
[0279]
FIG. 7 is a schematic view of a modified 1200 dpi laser beam printer (manufactured by Canon: LBP-840) using a non-magnetic one-component contact development type electrophotographic process. In this example, an apparatus in which the following parts (a) to (g) were modified was used.
[0280]
(A) The charging method of the apparatus was direct charging performed by contacting a rubber roller, and the applied voltage was a direct current component (-1200 V).
[0281]
(B) A medium resistance rubber roller (diameter 16 mm, hardness ASKER-C 45 degrees, resistance 10) made of silicone rubber in which carbon black is dispersed as a toner carrier.⁵Ω · cm) and contacted with the photoreceptor.
[0282]
(C) The toner carrying member was driven so that the rotational peripheral speed of the toner carrying member was in the same direction at the contact portion with the photosensitive member, and was 150% of the photosensitive member rotational peripheral speed.
[0283]
(D) The photoconductor was changed to the following.
[0284]
The photoreceptor used here was an Al cylinder as a substrate, and layers having the following constitution were sequentially laminated by dip coating to produce a photoreceptor.
Conductive coating layer: Mainly composed of a powder of tin oxide and titanium oxide dispersed in a phenol resin. Film thickness 15 μm.
-Undercoat layer: Mainly composed of modified nylon and copolymer nylon. Film thickness 0.6 μm. Charge generation layer: Mainly composed of a titanyl phthalocyanine pigment having absorption in a long wavelength region dispersed in a butyral resin. Film thickness 0.6 μm.
Charge transport layer: Mainly composed of a hole-transporting triphenylamine compound dissolved in a polycarbonate resin (molecular weight 20,000 by Ostwald viscosity method) at a mass ratio of 8:10. Film thickness 20 μm.
[0285]
(E) As a means for applying the toner to the toner carrier, an application roller made of foamed urethane rubber was provided in the developing unit and brought into contact with the toner carrier. A voltage of about −550 V is applied to the application roller.
[0286]
(F) In order to control the coat layer of the toner on the toner carrier, a 0.1 mm phosphor bronze blade coated with a 30 μm thick polyamide resin was used.
[0287]
(G) Only the DC component (-450 V) was applied during development.
[0288]
A commercially available paint is applied very thinly on the surface of a rubber roller having the same diameter, the same hardness, and the same resistance as the toner carrier used in the image forming apparatus, and after temporarily assembling the image forming apparatus, the rubber roller is removed, and an optical microscope By observing the surface of the phosphor bronze blade, the NE length was measured.
[0289]
The NE length was 1.05 mm.
[0290]
The electrophotographic apparatus was remodeled and process conditions were set as follows in order to conform to the remodeling of these process cartridges.
[0291]
The modified device uses a roller charger (applying only direct current) to uniformly charge the image carrier. Subsequent to charging, an image portion is exposed with a laser beam to form an electrostatic latent image, and a visible image is formed with toner, and then the toner image is transferred to a transfer material by a roller to which a voltage of +700 V is applied.
[0292]
As for the photosensitive member charging potential, the dark portion potential was set to -600V, and the bright portion potential was set to -150V.
[0293]
Under the above conditions, 2% printing is performed in a high temperature and high humidity environment (30 ° C., 80% RH), a normal temperature and normal humidity environment (23 ° C., 50% RH), and a low temperature low humidity environment (15 ° C., 10% RH). The image of the ratio was printed up to 10,000 sheets, and the image quality of the first sheet after being left in each environment for one day was evaluated by the following method.
[0294]
(1) Image fog
The fog density (%) is calculated from the difference between the whiteness of the white background portion of the printout image and the whiteness of the transfer paper measured by “REFECTRECTER MODEL TC-6DS” (manufactured by Tokyo Denshoku Co., Ltd.). Image fog was evaluated. The filter used was amber light for cyan, blue for yellow, and green for magenta and black.
A: Very good Less than 0.5%
B: Good 0.5% or more to less than 1.0%
C: No problem in practical use 1.0% or more to less than 1.5%
D: Somewhat difficult 1.5% or more
In the present invention, the rank C or higher is within the allowable range.
[0295]
(2) Halftone uniformity
One halftone image with an image density of 0.7 was output, each with and without dither, and the smoothness was evaluated according to the following criteria.
A: Very good Even in a dithered image, very uniform
B: Good Spots are slightly felt in an image without dither
C: No problem in practical use Dithered image
D: Slightly difficult Dithered image is clearly darker
[0296]
(3) Initial density change
Ordinary paper for ordinary copying machines (75 g / m²) Was used to output a solid image on the first and tenth sheets in an image forming test, and the degree of change in density was evaluated.
[0297]
The image density was measured by using a “Macbeth reflection densitometer RD918” (manufactured by Macbeth Co., Ltd.) to measure the relative density with respect to an image of a white background portion having a document density of 0.00.
A: Very good, less than 0.1
B: Good 0.1 or more and less than 0.15
C: No problem in practical use 0.15 or more and less than 0.2
D: Somewhat difficult 0.2 or more
[0298]
<Example 2>
The polar polymer to be added was changed from the polar polymer 1 to the polar polymer 2, and the addition amount of the aluminum complex of 3,5-di-t-butylsalicylic acid was changed to 0.7 part, as in Example 1. did.
[0299]
<Example 3>
The polar polymer to be added is changed from the polar polymer 1 to the polar polymer 3, the aluminum complex of 3,5-di-t-butylsalicylic acid is changed to a zirconium complex, and the number of added parts is changed to 1.0 part. Was the same as in Example 1.
[0300]
<Example 4>
The type of polar polymer to be added is changed from polar polymer 1 to polar polymer 4, the number of added parts is changed to 0.5 parts by mass, and the aluminum complex of 3,5-di-t-butylsalicylic acid is changed to a zinc complex. The procedure was the same as in Example 1 except that the number of added parts was changed to 1.5 parts.
[0301]
<Examples 5-6>
The same procedure as in Example 1 was conducted except that the kind and amount of polar polymer to be added and the amount of aluminum complex of 3,5-di-t-butylsalicylic acid were changed as shown in Table 2.
[0302]
<Example 7>
The kind and addition amount of the polar polymer to be added and the aluminum complex of 3,5-di-t-butylsalicylic acid were changed to an iron complex, and the addition amount was changed as shown in Table 2, and was the same as in Example 1. did.
[0303]
<Example 8>
In Example 1, the type of colorant to be added is C.I. I. Except for changing to Pigment Yellow 93, the procedure was the same as Example 1.
[0304]
<Example 9>
In Example 1, the type and amount of the colorant to be added were changed to C.I. I. The same procedure as in Example 1 was performed except that the pigment red 122 was changed to 8 parts by mass.
[0305]
<Example 10>
In Example 1, the type and amount of colorant to be added were set to carbon black (DBP oil absorption 42 cm).³/ 100g, specific surface area 60m²/ G) was the same as Example 1 except that it was changed to 8 parts.
[0306]
<Comparative Examples 1-4>
The same procedure as in Example 1 was conducted except that the kind and amount of polar polymer to be added and the amount of aluminum complex of 3,5-di-t-butylsalicylic acid were changed as shown in Table 2.
[0307]
<Comparative Example 5>
In Example 1, the same procedure as in Example 1 was performed except that the charge control agent to be added was changed to benzylnaphthoic acid having no central metal.
[0308]
<Comparative Example 6>
In Example 1, the type and amount of colorant to be added were set to carbon black (DBP oil absorption 42 cm).³/ 100g, specific surface area 60m²/ G) was changed to 8 parts, and the same procedure as in Example 1 was conducted except that the charge control agent was changed to a monoazo metal complex.
[0309]
The physical properties of the produced toner are shown together in Table 2.
[0310]
<Example 11>
Next, in a full-color printer LBP2510 (manufactured by Canon), [cyan toner produced in toner production example 1], [yellow toner produced in toner production example 8], [magenta toner produced in toner production example 9] , [Black toner produced in Toner Production Example 10] was filled in 200 g of the corresponding cartridge, and 10000 full-color images were evaluated. The results were evaluated according to Example 1. The results are shown in Table 3.
[0311]
[Table 2]

[0312]
[Table 3]

[0313]
【The invention's effect】
The toner of the present inventor uses a charge control resin of a polymer compound type having a sulfur atom that is extremely superior in durability deterioration, and a charge control agent having a specific complex structure excellent in charge rising property, and By using manufacturing technology to control the state of their existence at a high level, it is possible to provide high-quality images with little change in density at the initial stage and less fogging over the long term, regardless of the environment. it can.
[Brief description of the drawings]
FIG. 1 is a schematic configuration diagram of an example of an apparatus for performing an image forming method of the present invention.
FIG. 2 shows an example of a surface potential profile on the toner carrier of the present invention.
FIG. 3 is a schematic configuration diagram of another example of an apparatus for carrying out the image forming method of the present invention.
FIG. 4 is a schematic configuration diagram of another example of an apparatus for carrying out the image forming method of the present invention.
FIG. 5 is a schematic configuration diagram of another example of an apparatus for carrying out the image forming method of the present invention.
FIG. 6 is a schematic configuration diagram of another example of an apparatus for performing the image forming method of the present invention.
FIG. 7 is a schematic configuration diagram of a modified machine used in an embodiment of the present invention.
[Explanation of symbols]
1 Photoconductor
2 Charging roller
4Y color developer
4M each color developer
4Bk each color developer
4C each color developing device
5 Intermediate transfer drum
5a Conductive support
5b Elastic layer
6 Cleaner with cleaning blade
7 Transfer material tray
8 Transfer device
9 Fixing device
9a Heating roller for fixing
9b Pressure roller for fixing
10 Rotary unit
16a to 16d charging means
17a-17d developing means
18a-18d Cleaning means
19a to 19d Photosensitive drum
20 Static eliminator
22 Fixing means
23a Latent image forming means
23b-23d Latent image forming means
24a-24d Discharge means for transfer
25 Conveyor belt
26 Discharge port
27 Adsorption charging means
28a to 28d Separating static eliminating discharge means
29a to 29d Image forming unit
40 Intermediate transfer belt
41 Roller
42 Primary transfer roller
43a Secondary transfer counter roller
43b Secondary transfer roller
44 Primary transfer bias power supply
45 Bias power supply
46 Secondary transfer bias power supply
49 Belt cleaner
100 Developer
101 Development blade
102 Toner carrier
103 Application roller
104 Toner
105 Transfer object
106 Transfer member
107 Pressure roller for fixing
108 Heating roller for fixing
109 photoconductor
110 Primary charging member (charging roller)
110a Conductive elastic layer
110b cored bar
115 Charging bias power supply
116 Transfer bias power supply
117 Development bias power supply
123 exposure
138 Cleaner with cleaning blade
241 photoconductor
241a Photoconductive insulating material layer
241b Photosensitive layer
242 Charging roller
242a Conductive elastic layer
242b Core
243 exposure
244 Development unit
244-1 to 244-4 Developer
245 Intermediate transfer drum
245a Medium resistance elastic layer
245b Pipe-shaped conductive core
246 Transfer material
247 Transfer means
247a Bias roller
247a1 conductive elastic layer
247a2 cored bar
247c Tension roller
247d Secondary transfer bias power supply
248 Cleaning blade
249 Cleaning means
280 Removable cleaning means
281 Fixing means
P, S recording material
L Light source device
E Laser light

Claims (21)

In a non-magnetic toner comprising at least a binder resin, a colorant, a charge control agent, and a polymer having a sulfur atom,
The charge control agent is a metal compound of an aromatic oxycarboxylic acid, and the contained metal is a metal selected from the group consisting of aluminum, zinc, chromium, cobalt, nickel, zirconium, titanium, copper, and iron. The mass A (mg / g) of oxycarboxylic acid extracted from 1 g of the toner with a 0.1 mol / L sodium hydroxide aqueous solution is A = 0.10 to 3.00 mg / g (toner mass basis) In addition, the ratio (S / C) of the atomic number% (S) of the sulfur element to the atomic number% (C) of the carbon element present on the toner surface measured by X-ray photoelectron spectroscopy is 0.0003 to 0.0050. And
A nonmagnetic toner, wherein the toner has an average circularity of 0.955 to 0.995 and a circularity standard deviation of less than 0.035. The nonmagnetic toner according to claim 1, wherein the metal contained in the aromatic oxycarboxylic acid is a metal selected from the group consisting of aluminum, zinc, chromium, and zirconia. 3. The nonmagnetic toner according to claim 1, wherein the aromatic oxycarboxylic acid is salicylic acid or an alkyl salicylic acid having an alkyl group having 5 or less carbon atoms. The nonmagnetic toner according to claim 1, wherein the aromatic oxycarboxylic acid is 3,5-di-t-butylsalicylic acid. The relationship between A and S / C is the following formula (1)
3 × 10 ⁻⁵ <A × S / C <1.5 × 10 ⁻² (1)
The nonmagnetic toner according to claim 1, wherein the relationship is satisfied. The relationship between A and S / C is the following formula (2)
3 × 10 ⁻⁴ <A × S / C <1.4 × 10 ⁻² (2)
The nonmagnetic toner according to claim 1, wherein the relationship is satisfied. The toner is a toner synthesized by a suspension polymerization method. The polymer having sulfur atoms is contained in an amount of 0.1 to 2 parts by mass per 100 parts by mass of the toner, and the metal compound of the aromatic oxycarboxylic acid is contained in the toner. 7. The non-magnetic material according to claim 1, wherein the toner contains 0.1 to 2 parts by mass per 100 parts by mass of the toner, and the coefficient of variation in the number distribution of the toner is 40 or less. toner. The content ratio of the polymer (a) having the sulfur atom and the metal compound (b) of the aromatic oxycarboxylic acid is in the range of a: b = 90: 10 to 10:90, and the number distribution of the toner is The nonmagnetic toner according to claim 1, wherein the coefficient of variation is 35 or less. The content ratio of the polymer (a) having the sulfur atom and the metal compound (b) of the aromatic oxycarboxylic acid is in the range of a: b = 80: 20 to 20:80, and the number distribution of the toner is The nonmagnetic toner according to claim 1, wherein the coefficient of variation is 35 or less. The nonmagnetic toner according to claim 1, wherein the toner contains at least a release agent. In an image forming method having a developing step of visualizing the electrostatic latent image by transferring toner to the electrostatic latent image carried on the image carrier by developing means,
The developing means includes a rotatable toner carrier that carries toner and is disposed opposite to the image carrier, and a toner regulating member that regulates the amount of toner on the toner carrier. The surface potential at the start of body rotation 10 seconds is -5 to -50V,
The toner is a non-magnetic toner comprising at least a binder resin, a colorant, a charge control agent, and a polymer having a sulfur atom, and the charge control agent is a metal compound of an aromatic oxycarboxylic acid and is contained. Is a metal selected from the group consisting of aluminum, zinc, chromium, cobalt, nickel, zirconium, titanium, copper and iron, and is extracted from 1 g of the toner with a 0.1 mol / L sodium hydroxide aqueous solution. The mass A (mg / g) of oxycarboxylic acid is A = 0.10 to 3.00 mg / g (toner mass standard), and the atoms of carbon elements present on the toner surface measured by X-ray photoelectron spectroscopy analysis The ratio (S / C) of the atomic number% (S) of the elemental sulfur to the number% (C) is 0.0003 to 0.0050, and the average circularity of the toner is 0.9. In 5 to 0.995, an image forming method, wherein a circularity standard deviation is less than 0.035. The image forming method according to claim 11, wherein the surface potential is −10 to −40V. The image forming method according to claim 11 or 12, wherein the metal contained in the aromatic oxycarboxylic acid is a metal selected from the group consisting of aluminum, zinc, chromium and zirconia. 14. The image forming method according to claim 11, wherein the aromatic oxycarboxylic acid is salicylic acid or an alkyl salicylic acid having an alkyl group having 5 or less carbon atoms. 14. The image forming method according to claim 11, wherein the aromatic oxycarboxylic acid is 3,5-di-t-butylsalicylic acid. The relationship between A and S / C is the following formula (1)
3 × 10 ⁻⁵ <A × S / C <1.5 × 10 ⁻² (1)
The image forming method according to claim 11, wherein the relationship is satisfied. The relationship between A and S / C is the following formula (2)
3 × 10 ⁻⁴ <A × S / C <1.4 × 10 ⁻² (2)
The image forming method according to claim 11, wherein the relationship is satisfied. The toner is a toner synthesized by a suspension polymerization method. The polymer having sulfur atoms is contained in an amount of 0.1 to 2 parts by mass per 100 parts by mass of the toner, and the metal compound of the aromatic oxycarboxylic acid is contained in the toner. 18. The image formation according to claim 11, wherein the toner content is 0.1 to 2 parts by mass per 100 parts by mass of the toner, and the coefficient of variation in the number distribution of the toner is 40 or less. Method. The content ratio of the polymer (a) having the sulfur atom and the metal compound (b) of the aromatic oxycarboxylic acid is in the range of a: b = 90: 10 to 10:90, and the number distribution of the toner is 19. The image forming method according to claim 11, wherein the coefficient of variation is 35 or less. The content ratio of the polymer (a) having the sulfur atom and the metal compound (b) of the aromatic oxycarboxylic acid is in the range of a: b = 80: 20 to 20:80, and the number distribution of the toner is 19. The image forming method according to claim 11, wherein the coefficient of variation is 35 or less. The image forming method according to claim 11, wherein the toner contains at least a release agent.

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